JP7589239B2 - Compressible non-fibrous support material - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Patent Application No. 62/900,708, filed September 16, 2019, entitled "Bioabsorbable Resin for Additive Manufacturing," U.S. Provisional Patent Application No. 62/913,227, filed October 10, 2019, entitled "Bioabsorbable Resin for Additive Manufacturing," and U.S. Provisional Patent Application No. 63/053,863, filed July 20, 2020, entitled "Compressible 3D Printed Scaffolds," the disclosures of which are incorporated herein by reference in their entireties.

FIELD OF THEINVENTION
A compressible non-fibrous support material and methods of making and using the same are provided.

Surgical staplers are used in surgical procedures to close openings in tissue, blood vessels, ducts, shunts, or other objects or body parts relevant to a particular procedure. The openings may be naturally occurring, such as passageways in blood vessels or internal organs such as the stomach, or may be created by a surgeon during a surgical procedure, such as by creating a bypass or anastomosis in tissue or blood vessel puncture, or by tissue incision during a stapling procedure.

Some surgical staplers require the surgeon to select the appropriate staple having the appropriate staple height for the tissue being stapled. For example, the surgeon may select a tall staple for use with thick tissue and a short staple for use with thin tissue. However, in some situations, the tissue being stapled does not have a consistent thickness, and therefore the staples may not achieve the desired firing configuration at each staple site. As a result, the desired seal may not be formed at or near all stapled sites, which may allow blood, air, gastrointestinal fluids, and other fluids to seep through the unsealed sites.

Furthermore, staples, such as recessed channels, like other objects and materials that may be implanted with procedures such as stapling, generally lack some of the properties of the tissue in which they are implanted. For example, staples and other objects and materials may lack the natural flexibility of the tissue in which they are implanted and therefore cannot withstand the fluctuations in intra-tissue pressure at the implantation site. This can lead to undesirable tissue tearing and subsequent leakage at or near the site of the staple.

Therefore, there remains a need for improved instruments and methods that address current problems with surgical staplers.

A surgical end effector for use with a surgical stapler is provided. In one exemplary embodiment, the surgical end effector includes a cartridge and an anvil movable relative to the cartridge between an open position and a closed position, the cartridge having a plurality of staples disposed therein and a non-planar deck surface facing the anvil, the plurality of staples configured to be deployed into tissue, and a non-fibrous support material formed of at least one fused bioabsorbable polymer and configured to be releasably retained on the deck surface so that it can be attached to tissue by the plurality of staples in the cartridge, the support material having a first end and a second end, a longitudinal axis extending between the first end and the second end. The auxiliary material includes a first lattice structure extending from a first upper surface to a first bottom surface opposite the first upper surface, the first bottom surface being complementary to the deck surface and defining at least a portion of the cartridge contact surface of the auxiliary material such that the first bottom surface is configured to mate with at least a portion of the deck surface, and a second lattice structure disposed on at least a portion of the first upper surface of the first lattice structure, the second lattice structure having an outer upper surface at least a portion of which is substantially planar, the second outer upper surface defining at least a portion of the tissue contact surface of the auxiliary material. The first lattice structure has an uncompressed thickness that is at least partially different transverse to the longitudinal axis of the auxiliary material, thereby creating a consistent tissue gap between the anvil and the auxiliary material when the auxiliary material is releasably held on the cartridge and the anvil is in a closed position without tissue between the auxiliary material and the anvil, and the auxiliary material applies a substantially uniform pressure to tissue stapled to the auxiliary material for a predetermined period of time when in a tissue deployment state.

The first and second lattice structures may have various configurations. For example, in some embodiments, at least a portion of the second bottom surface of the second lattice may be configured to be positioned directly against the deck surface. In other embodiments, the first lattice structure may include a plurality of voids aligned with the plurality of staples, such that the first lattice structure does not contribute to the applied stress of the support material on the tissue stapled to the support material when in a tissue deployment state. In some embodiments, the first lattice structure may be formed of a plurality of vertical struts that extend from the deck surface to the second bottom surface of the second lattice structure when the support material is releasably held on the deck surface. In certain embodiments, the second lattice structure may include a plurality of unit cells, each of which may be a triply periodic minimal surface structure or may be defined by a plurality of interconnected struts. In some embodiments, the triply periodic minimal surface structure may be a Schwartz P structure. In other embodiments, the plurality of staples may be generally uniform, and the second lattice may include a first longitudinal row of first repeating unit cells having a first compression ratio and a second longitudinal row of second repeating unit cells having a second compression ratio greater than the first compression ratio. In certain embodiments, the second lattice may include a third longitudinal row of third repeating unit cells each having a third compression ratio greater than the second compression ratio, and the second longitudinal row may be positioned between the first and third longitudinal rows.

The repeating cell units may have a variety of configurations. For example, in some embodiments, each first repeating unit cell may have a first wall thickness and each second repeating unit cell may have a second wall thickness that is less than the first wall thickness. In other embodiments, each first repeating unit cell may have a first wall thickness, each second repeating unit cell may have a second wall thickness that is less than the first wall thickness, and each third repeating unit cell may have a third wall thickness that is less than the second wall thickness. In certain embodiments, the second repeating unit cell and the third repeating unit cell may be configured to be positioned relative to the first lattice structure.

In another exemplary embodiment, a surgical end effector includes a cartridge and an anvil movable relative to the cartridge between an open position and a closed position, the cartridge having a deck surface facing the anvil, the deck surface being non-planar; a first staple row and a second staple row disposed within the cartridge and extending longitudinally along the cartridge, the first staple row having a plurality of first staples having a first undeformed height and the second staple row having a plurality of second staples having a second undeformed height greater than the first undeformed height, the first staple row and the second staple row being configured to be deployed into tissue, the first staple row and the second staple row being formed of at least one fused bioabsorbable polymer; and a non-fibrous auxiliary material configured to be releasably held on the deck surface so that it can be attached to tissue by a plurality of first staples and a plurality of second staples in the cartridge, the auxiliary material including a first longitudinal row of a plurality of first repeating unit cells having a first geometric shape and a second longitudinal row of a plurality of second repeating unit cells having a second geometric shape different from the first geometric shape, such that the geometric shape of the auxiliary material varies transversely to the longitudinal axis of the auxiliary material, thereby creating a consistent tissue gap between the anvil and the auxiliary material when the auxiliary material is releasably held on the cartridge and the anvil is in a closed position without tissue between the auxiliary material and the anvil, and the auxiliary material applies a substantially uniform pressure to the tissue stapled to the auxiliary material for a predetermined period of time when in a tissue-expanded state.

The first repeat unit cells may have a variety of configurations. For example, each of the first repeat unit cells may have a first height and each of the second repeat unit cells may have a second height that is greater than the first height. In other embodiments, each of the first repeat unit cells may have a first wall thickness and each of the second repeat unit cells may have a second wall thickness that is greater than the first wall thickness. In certain embodiments, each of the first repeat unit cells may have a first compression ratio and each of the second repeat unit cells may have a second compression ratio that is less than the first compression ratio.

The auxiliary material can have a variety of configurations. For example, in some embodiments, the auxiliary material can include a third longitudinal row of a plurality of third repeating unit cells having a third geometric shape that can be different from the first geometric shape and the second geometric shape. In other embodiments, the third repeating unit cells can each have a third height, and the third height can be greater than each of the first height of the first repeating unit cell and the second height of the second repeating unit cell. In some embodiments, the third repeating unit cells can each have a third wall thickness, and the third wall thickness can be greater than each of the first wall thickness of the first repeating unit cell and the second wall thickness of the second repeating unit cell.

The first and second repeat unit cells may have various configurations. For example, in some embodiments, the first repeat unit cells may each have a first compression ratio, the second repeat unit cells may each have a second compression ratio less than the first compression ratio, and the third repeat unit cells may each have a third compression ratio less than the second compression ratio. In other embodiments, at least one of the first repeat unit cell and the second repeat unit cell may include one or more triply periodic minimal surface structures. In certain embodiments, at least one of the first repeat unit cell and the second repeat unit cell may include a Schwartzian P structure. In other embodiments, at least one of the first repeat unit cell and the second repeat unit cell may include a modified Schwartzian P structure.

The invention will be more fully understood from the following detailed description when read in conjunction with the accompanying drawings, in which:
1 is a perspective view of one exemplary embodiment of a conventional surgical stapling and severing instrument; FIG. 2 is a top view of a staple cartridge for use with the surgical stapling and severing instrument of FIG. FIG. 2B is a side view of the staple cartridge of FIG. 2A . FIG. 2B is a perspective view of a portion of the tissue contacting surface of the staple cartridge of FIG. 2A . FIG. 5 is a side view of a staple in an unfired (pre-deployed) configuration that may be disposed within the staple cartridge of the surgical cartridge assembly of FIG. FIG. 2 is a perspective view of a knife and firing bar ("E-beam") of the surgical stapling and severing instrument of FIG. 2 is a perspective view of a wedge sled of a staple cartridge of the surgical stapling and severing instrument of FIG. 1; FIG. A longitudinal cross-sectional view of an exemplary embodiment of a surgical cartridge assembly having a compressible non-fibrous support material attached to the top or deck surface of the staple cartridge. FIG. 6B is a longitudinal cross-sectional view of a surgical end effector having an anvil pivotally connected to an elongated staple channel and the surgical cartridge assembly of FIG. 6A positioned within and connected to the elongated staple channel, showing the anvil in a closed position with no tissue between the anvil and the auxiliary material. 6A-6B in a tissue-deployed state. FIG. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. FIG. 8B is a side view of the support material of FIG. 8A. FIG. 8B is a top view of the support material of FIG. 8A. A cross-sectional view of the support material of Figure 8C taken along line 8D-8D. A cross-sectional view of the support material of Figure 8C taken along line 8E-8E. 8F is an enlarged view of a portion of the support material of FIG. 8C taken at 8F. 8B is a partial schematic view showing the support material of FIG. 8A in a tissue deployment state. FIG. 8B is a side view of a single unit cell of the support material of FIG. 8A. FIG. 9B is a perspective view of a single unit cell of FIG. FIG. 2 is a schematic diagram of an exemplary unit cell in a pre-compressed state. FIG. 10B is a schematic diagram of the unit cell of FIG. 10A in a first compressed state. FIG. 10B is a schematic diagram of the unit cell of FIG. 10A in a second compressed state. FIG. 10B is a schematic diagram of the unit cell of FIG. 10A in a densified state. FIG. 10 is a schematic diagram of the relationship between the state of the unit cells of FIGS. 10A-10D and the resulting stress-strain curves of the compressible non-fibrous auxiliary material. FIG. 1 is a top view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from repeating unit cells of an embodiment of a modified Schwartz P structure. FIG. 2 is a top view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from repeating unit cells of another embodiment of a modified Schwartz P structure. FIG. 2 is a top view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from repeating unit cells of another embodiment of a modified Schwartz P structure. FIG. 2 is a top view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from repeating unit cells of another embodiment of a modified Schwartz P structure. FIG. 2 is a perspective view of another exemplary embodiment of a single unit cell. FIG. 13B is a top-down view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from the repeating unit cells of FIG. 13A. FIG. 2 is a perspective view of another exemplary embodiment of a single unit cell. FIG. 14B is a top-down view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from the repeating unit cells of FIG. 14A. FIG. 2 is a perspective view of another exemplary embodiment of a single unit cell. FIG. 15B is a top-down view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from the repeating unit cell of FIG. 15A. FIG. 2 is a perspective view of another exemplary embodiment of a single unit cell. FIG. 16B is a top-down view of an exemplary embodiment of a compressible non-fibrous auxiliary material formed from the repeating unit cells of FIG. 16A. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. A cross-sectional view of the support material of Figure 17A taken along line 17B-17B. A cross-sectional view of the support material of Figure 17A taken along line 17C-17C. FIG. 13 is a perspective view of another exemplary embodiment of a compressible non-fibrous support material disposed in a staple cartridge. FIG. 13 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material having channel attachment. A cross-sectional view of the support material of Figure 19A taken along line 19B-19B. FIG. 13 is a partial perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material having channel attachment. FIG. 13 is a partial perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material having channel attachment. FIG. 13 is a partially exploded perspective view of an exemplary embodiment of a stapling assembly having compressible non-fibrous support material releasably held on the staple cartridges, each having a corresponding edge attachment feature; FIG. 22B is an enlarged cross-sectional view of a portion of the stapling assembly taken along line 22B-22B showing the two edge attachment mechanisms prior to engagement. FIG. 22C is a cross-sectional view of a portion of the stapling assembly of FIG. 22B showing two edge attachment mechanisms engaged; FIG. 13 is a perspective view of another exemplary embodiment of a staple fastening assembly having compressible non-fibrous support material releasably held on a staple cartridge, each having corresponding edge attachment features, and having engaged edge attachment features; FIG. 23C is an enlarged view of a portion of the stapling assembly of FIG. 23B; 11 is a perspective view of another exemplary embodiment of a staple cartridge having end mounting features; 11 is a perspective view of another exemplary embodiment of a staple cartridge having end mounting features; FIG. 13 is an exploded view of another exemplary embodiment of a stapling assembly having a staple cartridge and a compressible non-fibrous support material having attachment features releasably retained on the cartridge. 26B is a cross-sectional view of the stapling assembly of FIG. 26A taken along line 26B-26B. 26C is a cross-sectional view of the stapling assembly of FIG. 26A taken along line 26C-26C. 11 is a partial cross-sectional view of another exemplary embodiment of a staple fastening assembly having a compressible non-fibrous support material releasably held on the staple cartridge; 11 is a partial cross-sectional view of another exemplary embodiment of a staple fastening assembly having a compressible non-fibrous support material releasably held on the staple cartridge; 28B is a partial schematic view showing the support material of FIG. 28A in a tissue deployment state. 11 is a partial cross-sectional view of another exemplary embodiment of a staple fastening assembly having a compressible non-fibrous support material releasably held on the staple cartridge; FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. FIG. 30B is a front plan view of the support material of FIG. 30A. FIG. 2 is a perspective view of one embodiment of a compressible non-fibrous auxiliary material. FIG. 31B is a perspective view of a single unit cell of the support material of FIG. 31A. FIG. 31C is a side view of a single unit cell of FIG. FIG. 31C is an alternative side view of the unit cell of FIGS. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. FIG. 32B is a perspective view of a single unit cell of the support material of FIG. 32A. FIG. 32C is a side view of the unit cell of FIG. 32B. FIG. 32D is a cross-sectional top view of the unit cell of FIGS. 32B-32C taken along line 32D-32D in FIG. 32C. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. FIG. 33B is a perspective view of a single unit cell of the support material of FIG. 33A. FIG. 33C is a side view of the unit cell of FIG. 33B. FIG. 33D is a cross-sectional top view of the unit cell of FIGS. 33B-33C taken along line 33D-33D of FIG. 33C. FIG. 33C is an alternative side view of the unit cell of FIGS. 33B-33C. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. FIG. 34B is a perspective view of a single unit cell of the support material of FIG. 34A. FIG. 34C is a side view of the unit cell of FIG. 34B. FIG. 34B is a top view of the unit cell of FIGS. 34B-34C. FIG. 34C is an alternative side view of the unit cell of FIGS. 34B-34C. FIG. 2 is a perspective view of another exemplary embodiment of a unit cell. FIG. 2 is a perspective view of another exemplary embodiment of a unit cell. FIG. 13 is a partially exploded perspective view of another exemplary embodiment of a stapling assembly having a staple cartridge and a compressible non-fibrous support material. 37B is a cross-sectional view of a portion of the stapling assembly taken along line 37B-37B of FIG. 37A. FIG. 37C is a schematic diagram of a portion of the stapling assembly of FIG. 37B showing tissue disposed on a support material; 37B is a partial schematic view showing the support material of FIG. 37A in a tissue deployment state. 1 is an exploded view of an exemplary embodiment of a stapling assembly having a staple cartridge and support material, with only the second outer layer of the support material being shown; FIG. 39B is a front view of the stapling assembly of FIG. 39A; FIG. 13 is a perspective view of another exemplary embodiment of a stapling assembly having a compressible non-fibrous support material releasably held on the staple cartridge; FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. A cross-sectional view of a portion of the support material of Figure 41A releasably held on the staple cartridge taken along line 41B-41B. A cross-sectional view of a portion of the support material of Figure 41A releasably retained on the staple cartridge taken along line 41C-41C. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. 42B is a partial schematic view showing the support material of FIG. 42A in a tissue deployment state. FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. A cross-sectional view of the support material of Figure 43A taken along line 43B-43B. A cross-sectional view of another exemplary embodiment of a compressible non-fibrous support material, showing only a portion of the support material releasably held on the staple cartridge. A partial schematic diagram showing tissue clamped between an anvil and a portion of the auxiliary material of Figure 44A, with staples partially deployed through the auxiliary material from the staple cartridge. 44B is a partial schematic view showing the support material of FIG. 44A in a tissue deployment state. FIG. 13 is a partially exploded perspective view of another exemplary embodiment of a stapling assembly having a compressible non-fibrous support material releasably retained on the staple cartridge; FIG. 45B is a top down view of a portion of the stapling assembly of FIG. 45A; 45C is a cross-sectional view of the stapling assembly of FIG. 45B taken along line 45C-45C. FIG. 13 is a perspective view of another exemplary embodiment of a portion of a stapling assembly having a compressible non-fibrous support material releasably held on the staple cartridge; FIG. 46B is a top down view of a portion of the stapling assembly of FIG. 46A; FIG. 1 is a cross-sectional front view of an exemplary embodiment of a surgical end effector having an anvil and a staple fastening assembly having a compressible non-fibrous support material releasably held on a staple cartridge, the surgical end effector shown in a closed position where no tissue is positioned between the anvil and the staple fastening assembly. FIG. 47B is a cross-sectional front view of the surgical end effector of FIG. 47A illustrating tissue clamped between the anvil and stapling assembly and stapled to a compressible non-fibrous support material; FIG. 47B is a cross-sectional front view of only the staple fastening assembly of FIG. 47A; FIG. 11 is a cross-sectional front view of another exemplary embodiment of a surgical end effector having an anvil and a staple fastening assembly having a compressible non-fibrous support material releasably held on the staple cartridge, showing the surgical end effector in a closed position where no tissue is positioned between the anvil and the staple fastening assembly. FIG. 48B is a cross-sectional front view of the surgical end effector of FIG. 48A showing tissue clamped between the anvil and stapling assembly and stapled to a compressible non-fibrous support material; FIG. 48B is a cross-sectional front view of only the staple fastening assembly of FIG. 48A; FIG. 2 is a perspective view of another exemplary embodiment of a compressible non-fibrous auxiliary material. FIG. 1 is a side view of an exemplary embodiment of a surgical end effector having an anvil and a staple fastening assembly having a compressible non-fibrous support material releasably held on a staple cartridge, the surgical end effector shown in a closed position where no tissue is positioned between the anvil and the staple fastening assembly. FIG. 50B is a side view of the surgical end effector of FIG. 50A showing tissue clamped between the anvil and the stapling assembly; FIG. 50B is a side view of only the stapling assembly of FIG. 50A; FIG. 11 is a cross-sectional front view of another exemplary embodiment of a surgical end effector having an anvil and a staple fastening assembly having a compressible non-fibrous support material releasably held on the staple cartridge, showing the surgical end effector in a closed position where no tissue is positioned between the anvil and the staple fastening assembly. FIG. 51B is a cross-sectional front view of only the compressible non-fibrous auxiliary material of FIG. 51A. FIG. 11 is a cross-sectional front view of another exemplary embodiment of a surgical end effector having an anvil and a staple fastening assembly having a compressible non-fibrous support material releasably held on the staple cartridge, showing the surgical end effector in a closed position where no tissue is positioned between the anvil and the staple fastening assembly. FIG. 52B is a cross-sectional front enlarged view of only a portion of the stapling assembly of FIG. 52A; A cross-sectional view of a portion of another exemplary embodiment of a compressible non-fibrous support material releasably held on a staple cartridge. A cross-sectional view of a portion of another exemplary embodiment of a compressible non-fibrous support material releasably held on a staple cartridge, showing only three staples from three staple rows of the staple cartridge. 55 is a schematic diagram of the stress-strain curve of the support material of FIG. 54 at each of three staples. 1 is a graph showing the stress-strain curve of an exemplary compressible non-fibrous auxiliary material (Auxiliary Material 1) of Examples 9 and 10. 1 is a graph showing stress-strain curves for four exemplary compressible non-fibrous auxiliary materials (Auxiliary Materials 2-5) of Examples 9 and 10. 1 is a graph showing stress-strain curves for six exemplary embodiments of the compressible non-fibrous auxiliary material of Example 11.

Specific exemplary embodiments will now be described to provide a general understanding of the principles of the structure, function, manufacture, and use of the auxiliary materials, systems, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will appreciate that the auxiliary materials, systems, and methods described in detail herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and the scope of the present invention is defined solely by the claims. Features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be within the scope of the present invention.

A surgical stapling assembly and methods of making and using the same are provided. Generally, the surgical stapling assembly may include a staple cartridge having staples disposed therein and a compressible bioabsorbable non-fibrous supplementary material configured to be releasably retained on the staple cartridge. In some embodiments, the non-fibrous supplementary material may be formed from a matrix including at least one fused bioabsorbable polymer and thus may be three-dimensionally printed. In other embodiments, the non-fibrous supplementary material may be formed in part or in whole via any suitable additive manufacturing process, such as injection molding, foaming, and forming processes, as will be understood by those skilled in the art. As discussed herein, various supplementary materials may be configured to compensate for changes in tissue properties, such as changes in tissue thickness, and/or to promote tissue ingrowth when the supplementary material is stapled to the tissue. For example, the supplementary material may be configured to undergo a strain in the range of about 0.1 (10% deformation) to 0.9 (90 percent deformation) while under an applied stress in the range of about 30 kPa to 90 kPa. That is, the auxiliary materials described herein can be configured to deform by about 10% to 90% when the auxiliary material is under stress of between and/or including about 30 kPa to 90 kPa, e.g., when the auxiliary material is in a tissue-deployed state.

The exemplary staple fastening assembly, as described herein and shown in the drawings, may include various features to facilitate application of surgical staples. However, one of ordinary skill in the art will understand that the staple fastening assembly may include only some of these features and/or may include various other features known in the art. The staple fastening assemblies described herein are intended to be representative of certain exemplary embodiments only. Additionally, while the auxiliary material is described in connection with a surgical staple cartridge assembly, the auxiliary material may be used in connection with staple reloading that is not a cartridge base or any type of surgical instrument.

FIG. 1 illustrates an exemplary surgical stapling and cutting device 100 suitable for use with an implantable support. The illustrated surgical stapling and cutting device 100 includes a staple applying assembly 106 or end effector having an anvil 102 pivotally coupled to an elongated staple channel 104. As a result, the staple applying assembly 106 can be moved between an open position, as shown in FIG. 1, and a closed position in which the anvil 102 is positioned adjacent to the elongated staple channel 104 and engages tissue therebetween. The staple applying assembly 106 can be attached at its proximal end to an elongated shaft 108 that forms an implement portion 110. When the staple applying assembly 106 is closed or at least substantially closed (e.g., the anvil 102 moves from the open position of FIG. 1 toward the elongated staple channel), the implement portion 110 can present a sufficiently small cross-section suitable for inserting the staple applying assembly 106 through a trocar. Although device 100 is configured to staple and cut tissue, surgical devices configured to staple but not cut tissue are also contemplated herein.

In various circumstances, the staple applying assembly 106 may be operated by a handle 112 connected to the elongated shaft 108. The handle 112 may include user controls, such as a rotation knob 114 for rotating the elongated shaft 108 and the staple applying assembly 106 about the longitudinal axis of the elongated shaft 108, and a closure trigger 116 that may pivot relative to a pistol grip 118 to close the staple applying assembly 106. For example, when the closure trigger 116 is clamped, a closure release button 120 may be presented on the outside of the handle 112 such that the closure release button 120 may be depressed to unclamp the closure trigger 116 and open the staple applying assembly 106.

The firing trigger 122 may pivot relative to the closure trigger 116, thereby allowing the staple applying assembly 106 to simultaneously cut and staple the tissue clamped therein. In various instances, multiple firing strokes may be used using the firing trigger 122 to reduce the amount of force required to be applied by the surgeon's hand per stroke. In certain embodiments, the handle 112 may include one or more rotatable indicator wheels, such as rotatable indicator wheel 124, that may indicate firing progress. A manual firing release lever 126 allows the firing system to be retracted, if necessary, before the firing system has completed its firing movement, and also allows the surgeon or other clinician to retract the firing system if the firing system becomes stuck and/or fails.

Further details regarding the surgical stapling and severing device 100 and other surgical stapling and severing devices suitable for use with the present disclosure are described, for example, in U.S. Pat. No. 9,332,984 and U.S. Patent Application Publication No. 2009/0090763, the entire disclosures of which are incorporated herein by reference. Additionally, the surgical stapling and severing device need not include a handle, but instead may have a housing configured to couple to a surgical robot, for example, as described in U.S. Patent Application Publication No. 2019/0059889, the entire disclosure of which is incorporated herein by reference.

As further shown in FIG. 1, a staple cartridge 200 may be utilized with instrument 100. During use, staple cartridge 200 is positioned within and coupled to elongated staple channel 104. In this illustrated embodiment, staple cartridge 200 may have a variety of configurations, but is shown in more detail in FIGs. 2A-2B has a proximal end 202a and a distal end 202b with a longitudinal axis (L _C ) extending between proximal end 202a and distal end 202b. As a result, when staple cartridge 200 is inserted into elongated staple channel 104 (FIG. 1), the longitudinal axis (L _C ) is aligned with the longitudinal axis (L _S ) of elongated shaft 108. Additionally, staple cartridge 200 includes a longitudinal slot 210 defined by two opposing walls 210a, 210b and configured to receive at least a portion of a firing member of a firing assembly, such as firing assembly 400 of FIGURE 4, as will be discussed in more detail below. As shown, longitudinal slot 202 extends from proximal end 202a toward distal end 202b of staple cartridge 200. It is also contemplated herein that in other embodiments, longitudinal slot 202 may be omitted.

The illustrated staple cartridge 200 includes staple cavities 212, 214 defined therein, each configured to removably receive at least a portion of a staple (not shown). The number, shape, and location of the staple cavities may vary and may depend at least on the size and shape of the staples to be removably disposed therein. In this illustrated embodiment, the staple cavities are arranged in two sets of three longitudinal rows, with a first set of staple cavities 212 positioned on a first side of the longitudinal slot 210 and a second set of staple cavities 214 positioned on a second side of the longitudinal slot 210. On each side of the longitudinal slot 210, and thus for each set of rows, the first longitudinal row of staple cavities 212a, 214a extends along the longitudinal slot 210, the second row of staple cavities 212b, 214b extends along the first row of staple cavities 212a, 214b, and the third row of staple cavities 212c, 214c extends along the second row of staple cavities 212b, 214b. For each set of rows, the first row of staple cavities 212a, 214b, the second row of staple cavities 212b, 214b, and the third row of staple cavities 214c, 214c are parallel to each other and to the longitudinal slot 210. Additionally, as shown, for each row set, the staple cavities 212b, 214b of the second row are offset relative to the staple cavities 212a, 212c, 214a, 214c of the first and third rows. In other embodiments, the staple cavity rows in each set 212, 214 are not parallel to one another and/or to the longitudinal slot 210.

The staples releasably stored in the staple cavities 212, 214 can have a variety of configurations. An exemplary staple 300 that can be releasably stored in each of the staple cavities 212, 214 is shown in FIG. 3 in its unfired (pre-deployed, unformed) configuration. The illustrated staple 300 includes a crown (base) 302 and two legs 304 extending from each end of the crown 302. In this embodiment, the crown 302 extends in a straight direction and the staple legs 304 have the same unformed height, in other embodiments, the crown can be a step-up crown, such as, for example, crowns 2804c, 2806c, 2808c in FIG. 28A, and/or the staple legs can have different unformed heights (see FIG. 29). Additionally, prior to the staples 300 being deployed, the staple crowns 302 can be supported by staple drivers positioned within the staple cartridge 200 while the staple legs 304 are at least partially contained within the staple cavities 212, 214. Additionally, the staple legs 304 can extend beyond a top surface, such as top surface 206, of the staple cartridge 200 when the staples 300 are in their unfired position. In certain instances, as shown in FIG. 3, the tips 306 of the staple legs 304 can be sharp and sharp, which can incise and pierce tissue.

In use, the staples 300 can be deformed from an unfired position to a fired position, with the staple legs 304 moving through the staple cavities 212, 214, penetrating tissue positioned between the anvil 102 and the staple cartridge 200, and coming into contact with the anvil 102. As the staple legs 304 deform against the anvil 102, the legs 304 of each staple 300 can capture a portion of tissue within each staple 300 and apply a compressive force to the tissue. Additionally, the legs 304 of each staple 300 can deform downwardly toward the crown 302 of the staple 300 to form a staple entrapment area within which tissue can be captured. In various instances, the staple entrapment area can be defined between an inner surface of the deformed legs and an inner surface of the crown of the staple. The size of the staple capture area may depend on several factors, such as, for example, the length of the legs, the diameter of the legs, the width of the crown, and/or the degree of deformation of the legs.

In some embodiments, all of the staples disposed within the staple cartridge 200 may have the same unfired (pre-deployed, unformed) configuration. In other embodiments, the staples may include at least two groups of staples each having a different unfired (pre-deployed, unformed) configuration, e.g., differing in height and/or shape relative to one another. For example, the staple cartridge 200 may include a first group of staples having a first height disposed within the first row of staple cavities 212a, 214a, a second group of staples having a second height disposed within the second row of staple cavities 212b, 214b, and a third group of staples having a third height disposed within the third row of staple cavities 212c, 214c. In some embodiments, the first, second, and third heights may be different, with the third height being greater than the first height and the second height. In other embodiments, the first and second heights are the same, but the third height is different and greater than the first and second heights. One of ordinary skill in the art will appreciate that other combinations of staples are contemplated herein.

Additionally, the staples may include one or more exterior coatings, such as sodium stearate, a lubricant, and/or an antimicrobial agent. The antimicrobial agent may be applied to the staple as its own coating or may be incorporated into another coating, such as a lubricant. Non-limiting examples of suitable antimicrobial agents include 5-chloro-2-(2,4-dichlorophenoxy)phenol, chlorhexidine, silver formulations (e.g., nanocrystalline silver), lauric acid ethyl ester (LAE), octenidine, polyhexamethylene biguanide (PHMB), taurolidine, lactic acid, citric acid, acetic acid, and salts thereof.

2A-2B, the staple cartridge 200 extends from a top or deck surface 206 to a bottom surface 208, with the top surface 206 configured as a tissue-facing surface and the bottom surface 208 configured as a channel-facing surface. As a result, as shown in FIG. 1, when the staple cartridge 200 is inserted into the elongated staple channel 104, the top surface 206 faces the anvil 102 and the bottom surface 208 (blocking) faces the elongated staple channel 104.

In some embodiments, the upper surface 206 can include a surface feature defined therein. For example, the surface feature can be a recessed channel defined within the upper surface 206. As shown in more detail in FIG. 2C, a first recessed channel 216 surrounds each of the first staple cavities 212a, 214a. Each of the first recessed channels 216 is defined by a substantially triangular wall 216a having a proximally facing apex, a distally facing apex, and a laterally outward facing apex. Additionally, each of the first recessed channels 216 includes a first floor 206a at a first height from the upper surface 206. A second recessed channel 218 surrounds each of the second staple cavities 212b, 214b. Each second recessed channel 218 is defined by a wall 218a that is substantially diamond-shaped with a proximal facing apex, a distal facing apex, a laterally inward facing apex, and a laterally outward facing apex relative to the longitudinal axis. Additionally, each second recessed channel 218 includes a second floor 206b at a second height from the upper surface 206. A third recessed channel 220 surrounds each third staple cavity 212c, 214c. Each third recessed channel 220 is defined by a substantially triangular wall 220a with a proximal facing apex, a distal facing apex, and a laterally inward facing apex relative to the longitudinal axis. Additionally, each third recessed channel 220 includes a third floor 206c at a third height from the upper surface 206. In some embodiments, the first height of the first recessed channel 216, the second height of the second recessed channel 218, and the third height of the third recessed channel 220 can have the same height. In other cases, the first height, the second height, and/or the third height can be different. Additional details regarding the surface features and other exemplary surface features can be found in U.S. Patent Publication No. 2016/0106427, which is incorporated by reference in its entirety. Additionally, as discussed in more detail below, these recessed channels 216, 218, 220 can be used to interact with a support material, such as the support material 2600 of FIGS. 26A-C, which can be releasably retained on the top surface of the cartridge prior to staple deployment.

4 and 5, a firing assembly such as, for example, firing assembly 400 may be utilized with a surgical stapling and cutting device such as device 100 of FIG. 1. The firing assembly 400 may be configured to advance a wedge sled 500 having wedges 502 configured to deploy staples from the staple cartridge 200 into tissue captured between an anvil, such as anvil 102 of FIG. 1, and a staple cartridge, such as staple cartridge 200 of FIG. 1. Additionally, an E-beam 402 at a distal portion of the firing assembly 400 may fire the staples from the staple cartridge. During firing, the E-beam 402 may also pivot the anvil toward the staple cartridge, thus moving the staple applying assembly from an open position toward a closed position. The illustrated E-beam 402 includes a pair of top pins 404, a pair of middle pins 406 that may be along a portion 504 of the wedge sled 500, and a bottom pin or foot 408. The E-beam 402 may also include a sharp cutting edge 410 configured to cut captured tissue as the firing assembly 400 advances distally and thus toward the distal end of the staple cartridge. Additionally, integrally molded, proximally projecting upper and middle guides 412 and 414 bracketing each vertical end of the cutting edge 410 may further define a tissue staging area 416 that aids in guiding tissue to the sharp cutting edge 410 prior to severing the tissue. The middle guide 414 may also be used to engage and fire staples in the staple applying cartridge by abutting the stepped central member 506 of the wedge sled 500 that effects staple formation by the staple applying assembly 106.

In use, the anvil 102 of FIG. 1 can be moved to a closed position by depressing a closure trigger, such as the closure trigger of FIG. 1, to advance the E-beam 402 of FIG. 4. The anvil can position tissue against at least the top surface 206 of the staple cartridge 200 in FIGS. 2A-2C. Once the anvil is properly positioned, the staples 300 of FIG. 3 disposed within the staple cartridge can be deployed.

As described above, to deploy the staples from the staple cartridge, the sled 500 of FIG. 5 can move from the proximal end toward the distal end of the cartridge body and thus from the proximal end toward the distal end of the staple cartridge. As the firing assembly 400 of FIG. 4 is advanced, the sled can contact and lift upwardly the staple drivers in the staple cartridge within the staple cavities 212, 214. In at least one example, the sled and staple drivers can each include one or more ramps, i.e., angled surfaces, which can cooperate to move the staple drivers upwardly from an unfired position. As the staple drivers are lifted upwardly within their respective staple cavities, the staples advance upwardly, causing the staples to exit their staple cavities and penetrate into tissue. In various instances, the sled can simultaneously move several staples upwardly as part of a firing sequence.

As discussed above, the stapling device may be used in combination with a compressible auxiliary material. Although an auxiliary material is shown and described below, those skilled in the art will understand that the auxiliary material disclosed herein may be used with other surgical instruments and need not be coupled to a staple cartridge as described. Furthermore, those skilled in the art will also understand that the staple cartridge need not be replaceable.

As discussed above, some surgical staplers often require the surgeon to select the appropriate staple having the appropriate staple height for the tissue being stapled. For example, the surgeon may utilize tall staples for use with thick tissue and short staples for use with thin tissue. However, in some situations, the tissue being stapled does not have a consistent thickness, and therefore the staples may not achieve the desired firing configuration for all portions of the stapled tissue (e.g., portions of thick tissue and portions of thin tissue). Inconsistent tissue thickness can result in undesirable leakage and/or tearing of the tissue at the site of the staple when staples of the same or substantially greater height are used, particularly when the staple site is exposed to internal pressure at the site of the staple and/or along the row of staples.

Thus, to avoid the need to consider staple height when stapling tissue during surgery, various embodiments of non-fibrous support materials are provided that can be configured to compensate for different thicknesses of tissue captured within a fired (deployed) staple. That is, the support materials described herein can also provide appropriate tissue compression within and between fired staples in combination with the support materials while allowing a set of staples having the same or similar heights to be used in stapling tissues of different thicknesses (e.g., from thin to thick tissue). Thus, the support materials described herein can maintain suitable compression for stapled thin or thick tissues, thereby minimizing tissue leakage and/or tearing at the staple site.

Alternatively or additionally, the non-fibrous support material may be configured to promote tissue ingrowth. In various instances, it is desirable to accelerate tissue ingrowth into the implantable support material to promote healing of the treated tissue (e.g., stapled and/or incised tissue) and/or to accelerate patient recovery. More specifically, tissue ingrowth into the implantable support material may reduce the incidence, extent, and/or duration of inflammation at the surgical site. Tissue ingrowth into and/or around the implantable support material may, for example, manage the spread of infection at the surgical site. In-growth of blood vessels, particularly white blood cells, into and/or around the implantable support material may combat infection in and/or around the implantable support material and adjacent tissue. Tissue ingrowth may also aid in the acceptance of foreign bodies (e.g., implantable support material and staples) by the patient's body and may reduce the likelihood that the patient's body will reject the foreign bodies. Rejection of the foreign bodies may result in infection and/or inflammation at the surgical site.

Unlike conventional support materials (e.g., non-three-dimensionally printed support materials such as foam support materials and woven/nonwoven support materials), these non-fibrous support materials can be three-dimensionally (3D) printed and therefore formed with microstructures (units) that are consistently reproducible. That is, unlike other manufacturing methods, 3D printing significantly improves control over microstructural features, such as element positioning and connection. As a result, variability in both the microstructure and associated properties of the support material is reduced compared to conventional support materials. For example, the support material can be structured to compress a predetermined amount with a substantially uniform substance. Fine control over the microstructure can also allow the porosity of the support material to be tailored to enhance tissue ingrowth. The non-fibrous support material can also be adapted for use with a variety of staples and tissue types.

Generally, the auxiliary materials provided herein are designed and positioned on a staple cartridge, such as cartridge 200. When the staples are fired (deployed) from the cartridge, they penetrate through the auxiliary material into the tissue. When the legs of the staples are deformed against an anvil located on the opposite side of the staple cartridge, the deformed legs capture a portion of the auxiliary material and a portion of the tissue within each staple. That is, when the staples are fired into the tissue, at least a portion of the auxiliary material is disposed between the tissue and the fired staple. Although the auxiliary materials described herein may be configured to be attached to a staple cartridge, it is also contemplated herein that the auxiliary materials may be configured to mate with components of other instruments, such as the anvil of a surgical stapler. One skilled in the art will appreciate that the auxiliary materials provided herein may be used with replaceable cartridges or staple reloads that are not cartridge-based.

Method of Stapling Tissue FIGS. 6A-6B show an exemplary embodiment of a staple fastening assembly 600 including a staple cartridge 602 and an auxiliary material 604. For brevity, the auxiliary material 604 is generally shown in FIGS. 6A-6B, and various structural configurations of the auxiliary material are described in more detail below. Other than the differences described in detail below, the staple cartridge 602 can be similar to the staple cartridge 200 (FIGS. 1-3), and thus the common features will not be described in detail herein. As shown, the auxiliary material 604 is disposed relative to the staple cartridge 602. Although partially obstructed in FIG. 6, the staple cartridge 602 includes staples 606, which can be similar to the staples 300 of FIG. 3 that are configured to be deployed within tissue. The staples 606 can have any suitable unformed (pre-deployed) height. For example, the staples 606 can have an unformed height of about 2 mm to 4.8 mm. Prior to deployment, the crown of the staple may be supported by a staple driver (not shown).

In the illustrated embodiment, the support material 604 can be fitted to at least a portion of the top surface or deck surface 608 of the staple cartridge 602. In some embodiments, the top surface 608 of the staple cartridge 602 can include one or more surface features, such as recessed channels 216, 218, 220, as shown in FIGS. 2A and 2C. The one or more surface features can be configured to engage the support material 604 to prevent undesired movement of the support material 604 relative to the staple cartridge 602 and/or premature release of the support material 604 from the staple cartridge 602. Exemplary attachment mechanisms are described in U.S. Patent Application Publication No. 2016/0106427, which is incorporated herein by reference in its entirety.

FIG 6B illustrates a staple fastening assembly 600 disposed within and coupled to an elongated staple channel 610 of a surgical end effector 601, which is similar to the surgical end effector 106 of FIG 1. An anvil 612 is pivotally coupled to the elongated staple channel 610 and thus movable between an open position and a closed position relative to the elongated staple channel 610 and thus the staple cartridge 602. The anvil 612 is shown in the closed position in FIG 6B illustrating a tissue gap T _G created between the staple cartridge 602 and the anvil 612. More specifically, the tissue gap T _G is defined by the distance between a tissue compressing surface 612a of the anvil 612 (e.g., a tissue engaging surface between the staple forming pockets in the anvil) and a tissue contacting surface 604a of the support material 604. In this illustrated embodiment, both the tissue compression surface 612a of the anvil 612 and the tissue contact surface 604a of the support member 604 are planar or substantially planar (e.g., planar within manufacturing tolerances). As a result, as shown in FIG. 6B, when the anvil 612 is in the closed position, the tissue gap T _G is generally uniform (e.g., nominally the same within manufacturing tolerances) when no tissue is disposed therein. In other words, the tissue gap T _G is generally constant (e.g., constant within manufacturing tolerances) across the end effector 601 (e.g., in the y direction). In other embodiments, the tissue compression surface of the anvil may include a stepped surface having a longitudinal step between adjacent longitudinal portions, thus creating a stepped profile (e.g., in the y direction). In such embodiments, the tissue gap T _G may vary.

The auxiliary material 604 is compressible, such that the auxiliary material can be compressed to various heights to compensate for the different tissue thicknesses captured within the deployed staple. The auxiliary material 604 has an uncompressed (non-deformed) or pre-deployed height and is configured to be deformed to one of a plurality of compressed (deformed) or deployed heights. For example, the auxiliary material 604 can have an uncompressed height that is greater than the fired height of the staple 606 disposed within the staple cartridge 602 (e.g., the height (H) of the fired staple 606a in FIG. 7). That is, the auxiliary material 604 can have an undeformed state in which the maximum height of the auxiliary material 604 is greater than the maximum height of the fired staple (e.g., the staple in a formed configuration). In one embodiment, the uncompressed height of the support material 604 may be about 10% higher, about 20% higher, about 30% higher, about 40% higher, about 50% higher, about 60% higher, about 70% higher, about 80% higher, about 90% higher, or about 100% higher than the fired height of the staples 606. In certain embodiments, the uncompressed height of the support material 604 may be, for example, more than 100% higher than the fired height of the staples 606.

In use, when a surgical stapling and cutting device, such as device 100 of FIG. 1, is directed to a surgical site, tissue is positioned between the anvil 612 and the stapler assembly 600 (e.g., the tissue may be positioned against the tissue contact surface 604a of the support material 604) such that the anvil 612 is positioned adjacent a first side of the tissue and the stapler assembly 600 is positioned adjacent a second side of the tissue. When the tissue is positioned between the anvil 612 and the stapler assembly 600, the surgical stapler may be actuated, for example, as described above, to clamp the tissue between the anvil 612 and the stapler assembly 600 (e.g., between the tissue compression surface 612a of the anvil 612 and the tissue contact surface 604a of the support material 604) and deploy staples from the cartridge through the support material and into the tissue to attach the support material to the tissue.

As shown in FIG. 7, when the staples 606 are fired, the tissue (T) and a portion of the auxiliary material 604 are captured by the fired (formed) staples 606a. The fired staples 606a each define a capture area therein, as described above, to accommodate the captured auxiliary material 604 and tissue (T). The capture area defined by the fired staples 606a is limited, at least in part, by the height (H) of the fired staples 606a. For example, the height of the fired staples 606a can be about 0.160 inches or less. In some embodiments, the height of the first stapled staples 606a can be about 0.130 inches or less. In one embodiment, the height of the fired staples 606a can be about 0.020 inches to 0.130 inches. In another embodiment, the height of the fired staples 606a can be about 0.060 inches to 0.160 inches.

As noted above, the auxiliary material 604 may be compressed within a plurality of fired staples, regardless of whether the thickness of the tissue captured within the staple is the same or different within each fired staple. In at least one exemplary embodiment, the staples within the row of staples may be deformed to a fired height of, for example, about 2.75 mm, and the tissue (T) and auxiliary material 604 may be compressed within this height. In certain cases, the tissue (T) may have a compressed height of about 1.0 mm and the auxiliary material 604 may have a compressed height of about 1.75 mm. In certain cases, the tissue (T) may have a compressed height of about 1.50 mm and the auxiliary material 604 may have a compressed height of about 1.25 mm. In certain cases, the tissue (T) may have a compressed height of about 1.75 mm and the auxiliary material 604 may have a compressed height of about 1.00 mm. In certain cases, the tissue (T) may have a compressed height of about 2.00 mm and the auxiliary material 604 may have a compressed height of about 0.75 mm. In certain cases, the tissue (T) may have a compressed height of about 2.25 mm and the auxiliary material 604 may have a compressed height of about 0.50 mm. Thus, the sum of the compressed heights of the captured tissue (T) and the auxiliary material 604 may be equal to, or at least substantially equal to, the height (H) of the fired staple 606a.

Furthermore, most structures typically behave in a manner that increases the strain (deformation) of the material as the stress applied to the material increases. However, for surgical stapling, the strain of the support material increases over a relatively narrow stress range, and therefore, as discussed in more detail below, it is desirable that the support materials described herein can be structured so that they can exhibit a flat or gently sloping "stress plateau". Generally, the stress plateau is a regime in the stress-strain curve of the cellular material during compression that corresponds to progressive cell collapse by elastic buckling, and depends on the nature of the solid from which the material is made. That is, as a given structure deforms under compression, the strain may increase without a substantial increase in stress, thus resulting in a stress plateau, thereby advantageously delaying the densification (e.g., solid height) of the structure. As a result, the support materials described herein can be designed to undergo compression for extended periods of time over the entire stress range typically applied to the support material while in a tissue-deployed state (e.g., when the support material is stapled to tissue in vivo).

Thus, the structure of the support material may be designed to be capable of undergoing strains in the range of about 0.1 to 0.9 while under an applied stress in the range of about 30 kPa to 90 kPa when the support material and tissue are captured within the fired staples. When the support material is in a tissue-deployed state, the applied stress is the stress that the stapled tissue exerts on the support material. Those skilled in the art will appreciate that the stress exerted by the tissue depends on various stapling conditions (e.g., tissue thickness, height of the formed staple, intra-tissue pressure). For example, hypertension is typically considered to be 210 mmHg, and therefore, it would be desirable for the support material to withstand an applied stress of 210 mmHg or more for a predetermined period of time without reaching densification. In other embodiments, the strain may range from about 0.1 to 0.8, about 0.1 to 0.7, about 0.1 to 0.6, about 0.2 to 0.8, about 0.2 to 0.7, about 0.3 to 0.7, about 0.3 to 0.8, about 0.3 to 0.9, about 0.4 to 0.9, about 0.4 to 0.8, about 0.4 to 0.7, about 0.5 to 0.8, or about 0.5 to 0.9. Thus, the support material described herein may be configured to deform to not reach its solid height while under a predetermined amount of applied stress.

The principles of Hooke's Law (F=kD) can be used to design the support material that is configured to undergo a strain in the range of about 0.1 to 0.9 while under an applied stress of about 30 kPa to 90 kPa. For example, if the force (stress) applied to the support material deployed in tissue is known, the support material can be designed to have a predetermined stiffness (k). The stiffness can be set by adjusting the geometry of the support material (e.g., the shape, wall thickness, height, and/or interconnectivity of the unit cells, e.g., the angle and space between the unit cells, and/or the diameter of the struts of the unit cells, and/or the interconnectivity of the struts of the unit cells, e.g., the angle and space between the struts). Furthermore, the support material can be designed to have a maximum amount of compression displacement for a minimum tissue thickness of tissue, e.g., 1 mm, and therefore, when stapled to tissue for a given maximum staple height, e.g., 2.75 mm, the length of the displacement D can be a combination of the minimum thickness of tissue, e.g., 1 mm, and the thickness of the support material. By way of example, in one embodiment, the auxiliary material may be structured to have a maximum stapled height greater than 2.75 mm formed and compress to a height of 1.75 mm when stapled to tissue with a minimum thickness of 1 mm. The auxiliary material may therefore vary in compressibility to maintain a constant length displacement D such that the combined stiffness (k) and thickness (D) of the captured tissue and the auxiliary material can apply a stress of 3 gf/ ^mm2 to the captured tissue. It should be noted that those skilled in the art will appreciate that the above equations may be modified to account for changes in temperature, for example, when the auxiliary material goes from room temperature to body temperature after implantation. Furthermore, the above discussion of Hooke's law represents an approximation. Thus, those skilled in the art will appreciate that a more accurate prediction of the relationship between stress and strain can be obtained through the use of constitutive equations adjusted to the material of interest using the principles of large deformation mechanics (also known as finite elasticity).

Thus, the compressibility profile of the auxiliary material can be controlled by at least the structural configuration of the unit cells and the interconnections therebetween. As a result, the structural configuration of the unit cells can be tailored to affect the auxiliary material with desired mechanical properties for stapling tissue. Since there is a finite range of intra-tissue pressures, tissue thicknesses, and formed staple heights, an appropriate geometric configuration, and therefore unit cells, can be determined for the auxiliary material that can be effective to allow the auxiliary material to undergo a desired amount of strain at a substantially constant rate while a desired amount of stress is applied. In other words, the structural configuration of the unit cells can be designed to produce an auxiliary material that can be effective to apply a substantially continuous desired (e.g., at least 3 gf/mm ² ) stress to the stapled tissue for a given time over a range of staple conditions. That is, as described in more detail below, the present auxiliary material is formed of a compressible material and is geometrically configured to allow the auxiliary material to compress to various heights in a predetermined plane when stapled to tissue. Furthermore, this different response by the support material may also enable the support material to maintain a continuous desired stress on tissue when exposed to fluctuations in intratissue pressure (e.g., sudden increases in blood pressure) that may occur when the support material is stapled to tissue.

Supplementary Material The supplementary material can have a variety of configurations. The supplementary material generally includes a tissue contacting surface and a cartridge contacting surface with an elongate body (e.g., an internal structure) positioned therebetween. The tissue contacting surface and/or the cartridge contacting surface can have a different structure than the elongate body to form a tissue contacting layer and a cartridge contacting layer, respectively, in certain embodiments. As described in more detail below, the supplementary material can have a strut-based configuration, a non-strut-based configuration, or a combination thereof.

Additionally, each exemplary support material is shown in partial form (e.g., not the entire length), and thus, one of ordinary skill in the art will understand that the support material may be longer in length, for example, along its longitudinal axis ( _LA ), as specified in each embodiment. The length may vary based on the length of the staple cartridge or anvil. The width may also vary as needed. Additionally, each exemplary support material is configured to be positioned on the cartridge or anvil such that the longitudinal axis L of each support material is aligned with and extends along the longitudinal axis ( _LA ) of the cartridge or anvil. These support materials are structured to compress when exposed to a compressive force (e.g., stress or load).

The auxiliary materials described herein may have a variety of average lengths, widths, and thicknesses. For example, in some embodiments, the auxiliary materials may have an average length in the range of about 20 mm to 100 mm or about 40 mm to 100 mm. In other embodiments, the auxiliary materials may have an average width in the range of about 5 mm to 10 mm. In still other embodiments, the auxiliary materials may have an average thickness in the range of about 1 mm to 6 mm, about 1 mm to 8 mm, about 2 mm to 6 mm, or about 2 mm to 8 mm. In one embodiment, an exemplary auxiliary material may have an average length in the range of about 20 mm to 100 mm, an average width of 5 mm to 10 mm, and an average thickness of about 1 mm to 8 mm.

The elongated body may be formed of one or more lattice structures, each formed by interconnected unit cells. The unit cells may have various configurations, but in some embodiments, the unit cells may be pillar-based unit cells, while in other embodiments, the unit cells may be pillar-based unit cells. The pillars may be solid rods or bars formed entirely or substantially of a solid material. In certain embodiments, the one or more lattice structures may be formed by interconnected repeating unit cells. Furthermore, in certain embodiments, the elongated body may include at least one lattice structure formed of pillar-based unit cells and at least one lattice structure formed of pillar-based unit cells (see FIG. 54).

Each lattice structure extends from a first surface (e.g., a top surface) to a second surface (e.g., a bottom surface). Depending on the overall structural configuration of the support material, at least a portion of the first surface of at least one lattice structure may function as a tissue contact surface of the support material, and at least a portion of the second surface of at least one lattice structure may function as a cartridge contact surface of the support material. Those skilled in the art will appreciate that each lattice structure may have additional tissue contact surfaces (e.g., one or more lateral sides relative to the top surface).

In certain embodiments, the support material may include a tissue contact layer disposed on at least a portion of a first surface of at least one lattice structure of the internal structure. The tissue contact layer has a thickness extending between the first surface (e.g., a top surface) and the second surface (e.g., a bottom surface). As a result, the first surface of the tissue contact layer may function alone or in combination with at least a portion of the first surface of the at least one lattice structure as the tissue contact surface of the resulting support material. The tissue contact layer may have a variety of configurations. For example, in some embodiments, the tissue contact layer is in the form of a lattice structure formed of interconnecting repeating cells that may differ from the lattice structure of the elongate body, while in other embodiments, the tissue contact layer is in the form of a film.

Alternatively or additionally, the support may include a cartridge contact layer disposed on at least a portion of the second surface of the at least one lattice structure. The cartridge contact layer may have a thickness extending from the first surface (e.g., top surface) to the second surface (e.g., bottom surface). As a result, the second surface of the cartridge contact layer may function alone or in combination with at least a portion of the second surface of the at least one lattice structure as the cartridge contact surface of the resulting support. The cartridge contact layer may have a variety of configurations. For example, in some embodiments, the cartridge contact layer is in the form of a lattice structure formed of interconnecting repeating cells that may differ from the lattice structure of the elongated body, while in other embodiments, the cartridge contact layer is in the form of a film. In some embodiments, the film may be a pressure sensitive adhesive, while in other embodiments, the film may include one or more attachment features extending therethrough.

As described above, the support material may include a lattice structure formed of a strut-free based unit cell (e.g., a repeating strut-free based unit cell). In other words, in contrast to a strut-based unit cell, which is characterized by the presence of sharp corners or angles, a strut-free based unit cell may be characterized by a curved surface. For example, the unit cell may be based on a triply periodic minimal surface (TPMS). A TPMS is a minimal surface that repeats itself in three dimensions. As used herein, the term "minimal surface" refers to a mathematically known minimal surface. Thus, in some embodiments, the unit cell may be a Schwarz structure (e.g., Schwarz P, Schwarz Diamond), a modified Schwarz structure, a gyroid (e.g., Schoen Gyroid) structure, a cosine structure, and a coke can structure.

As discussed in more detail below, the pillar-free unit cells can have a variety of structural configurations (e.g., height, width, wall thickness, shape). In some embodiments, the pillar-free based unit cells of the support material can be substantially uniform (e.g., nominally identical within manufacturing tolerances), while in other embodiments, at least a portion of the pillar-free based unit cells of the support material can differ in shape and/or size relative to the remainder of the pillar-based unit cells.

For example, in some embodiments, each of the post-free based unit cells may have a wall thickness of about 0.05 mm to 0.6 mm. In certain embodiments, the wall thickness may be about 0.1 mm to 0.3 mm. In one embodiment, the wall thickness may be about 0.2 mm. In certain embodiments, the wall thickness of all post-free based unit cells of the auxiliary material may be substantially uniform (e.g., nominally the same within manufacturing tolerances). In other embodiments, for example, when the auxiliary material is formed of two or more sets of unit cells, the unit cells of each set may have different wall thicknesses. For example, in one embodiment, the auxiliary material may include first repeating unit cells each having a first wall thickness, second repeating unit cells each having a second wall thickness greater than the first wall thickness, and third repeating unit cells each having a third wall thickness greater than the second wall thickness. Alternatively or additionally, the first repeating unit cell can have a first height (e.g., a maximum height), a second height (e.g., a maximum height) that is greater than the first height, and a third height (e.g., a maximum height) that is greater than the second height.

In some embodiments, each unit cell may have a surface area to volume ratio of about 5 to 30. In certain embodiments, each unit cell may have a surface area to volume ratio of about 7 to 20.

Schwartz P Structure Figures 8A-8F are an exemplary embodiment of a support material 800 having a tissue contacting surface 802 and a cartridge contacting surface 804. The support material 800 includes interconnected repeating strutless unit cells 810, one of which is shown in more detail in Figures 9A-9B. Although the support material 800 is shown as having four longitudinal rows ( _L1 , _L2 , _L3 , _L4 ), each having 20 repeating unit cells 810, one of ordinary skill in the art will appreciate that the number of rows and unit cells of the support material can depend at least on the size and shape of the staple cartridge and/or anvil to which the support material is applied, and thus the support material is not limited to the number of longitudinal rows and unit cells shown in the figures. Additionally, while only one type of repeating strutless unit cell is shown, in other embodiments the support material can be formed of a combination of a first repeating strutless unit cell and a second strutless unit cell different from the first, etc.

Given that the support material 800 is formed of repeating unit cells 810 having substantially the same (e.g., nominally identical within manufacturing tolerances) structural configuration, the following discussion will be directed to one repeating unit cell 810. As shown in Figures 9A-9B, the repeating unit cell 810 has a top portion 812, a bottom portion 814, and a middle portion 816 extending therebetween.

In this illustrated embodiment, the repeating unit cell 810 is configured as a Schwartzian P structure, and thus the surface contour of the unit cell 810 is defined by a minimal surface. That is, the outer surface 820 and the inner surface 822 of the unit cell 810 are each defined by a minimal surface. Thus, in this illustrated embodiment, the outer surface 820 and the inner surface 822 are generally concave in shape, thereby forming an arcuate side 821 of the unit cell 810. Furthermore, the inner surface 822 defines an interior volume 824 of the unit cell 810. As a result, the unit cell 810 may be characterized as hollow. The Schwartzian P minimal surface may be functionally represented as cos(x)+cos(y)+cos(z)=0.

The unit cell 810 also includes connection interfaces 826 that can be used to interconnect the unit cell 810 to other unit cells 810, thereby forming the support 800 shown in Figures 8A-8E. In this illustrated embodiment, the unit cell includes six connection interfaces 826 that form the six outermost surfaces of the unit cell 810, such as a top outermost surface 827a and a bottom outermost surface 827b, a left outermost surface 829a and a right outermost surface 829b, and a front outermost surface 831a and a rear outermost surface 831b. Top and bottom outermost surfaces 827a, 827b are generally planar (e.g., planar within manufacturing tolerances) relative to one another and offset in the x-direction, left and right outermost surfaces 829a, 829b are generally planar (e.g., planar within manufacturing tolerances) relative to one another and offset in the y-direction, and front and rear outermost surfaces 831a, 831b are generally planar (e.g., planar within manufacturing tolerances) relative to one another and offset in the z-direction. Thus, the overall exterior surface of unit cell 810 includes planar surfaces, e.g., outermost surfaces 827a, 827b, 829a, 829b, 831a, 831b, and non-planar surfaces, e.g., exterior surface 820 extending between connection interface 826. Furthermore, because the auxiliary material 800 is formed only of the repeating unit cells 810, the top portion 812, including the top outermost surface 812a, forms the tissue contacting surface 802 of the auxiliary material 800, and the bottom outermost surface 814a (e.g., in the x-direction) of the bottom portion 814 of the unit cell forms the cartridge contacting surface 804 of the auxiliary material 800. As a result, the tissue contacting surface 802 is formed of planar and non-planar surfaces.

Further, based on the overall geometry of the repeating unit cells 810 and their interconnectivity to one another at the corresponding connection interfaces 826, the overall outer surface of the resulting auxiliary material 800 is formed with generally planar surfaces (e.g., planar within manufacturing tolerances) separated by non-planar surfaces. As shown, the outermost surfaces 850a, 850b of the top and bottom of the auxiliary material 800 are furthest from a bisector extending in the YZ plane, the outermost surfaces 852a, 852b of the left and right parts of the auxiliary material 800 are furthest from a bisector extending in the XZ plane, and the outermost surfaces 854a, 854b of the front and rear parts of the auxiliary material are furthest from a bisector extending in the XY plane. Additionally, as shown, the top and bottom outermost surfaces 850a, 850b are generally planar (e.g., planar within manufacturing tolerances) relative to one another and offset in the x-direction, the left and right outermost surfaces 852a, 852b are generally planar (e.g., planar within manufacturing tolerances) relative to one another and offset in the y-direction, and the front and rear outermost surfaces 854a, 854b are generally planar (e.g., planar within manufacturing tolerances) relative to one another and offset in the z-direction. Thus, these outermost surfaces 850a, 850b, 852a, 852b, 854a, 854b form planar segments of the exterior surface of the support material 800. It can be seen that the portion of the auxiliary material 800 extending between these outermost surfaces 850a, 850b, 852a, 852b, 854a, 854b is defined by the outer surfaces 820 of the adjacent unit cells 810, thereby forming a non-planar surface of the outer surface of the auxiliary material 800.

As further shown, the six connection interfaces 826 define respective circular openings in fluid communication with the interior volume 824 of the unit cell 810. As a result, the unit cell 810 has openings on all six Cartesian sides (represented as arrows 1, 2, 3, 4, 5, 6 in FIG. 9B). These openings can serve multiple functions, for example: facilitating connections to adjacent cells; creating openings that can allow for immediate tissue ingrowth when the support material is stapled to tissue; allowing drainage of the resulting support material, e.g., the manufacturing material used to generate the material used during the 3D manufacturing process; allowing movement of bodily fluids throughout the support material; contributing to the mechanical properties of the support material, e.g., creating a compression profile that delays densification of the support material; and/or minimizing the solid height of the fully compressed support material.

Furthermore, when the unit cells 810 are interconnected with each other at the corresponding connection interfaces, for example, at least two connection interfaces, hollow tubular interconnections 828 (e.g., lumens), are formed between the unit cells, as shown in Figures 8D-8E, which allow the internal volumes 824 of the interconnected unit cells 810 to be in fluid communication with each other. Thus, a continuous network of channels or pathways exists within the support material. As a result, when the support material 800 is stapled to the tissue (T) and is in a tissue deployment state as shown in Figure 8G, for example, one or more fluids containing cells that enter the support material 800 through the opening of the connection interface 826a of the upper portion 812 of at least one unit cell 810 can migrate throughout the support material 800, for example, through the interconnected unit cells, when in a tissue deployment state as shown in Figure 8G, and ultimately accelerate the in-growth of tissue within the support material 800. That is, while the support material 800 is in a tissue-deployed state, at least a portion of the hollow tubular interconnects 828 at least partially maintain fluid communication between at least a portion of the unit cells 810 or throughout the entire internal volume, and thus may facilitate cell mobility throughout the support material 800.

The hollow tubular interconnects 828 define openings that may have a variety of sizes (e.g., diameters), but in some embodiments, the openings may have a diameter of about 100 micrometers to 3500 micrometers. For example, the openings may have a diameter of about 100 micrometers to 2500 micrometers, or about 500 micrometers to 2500 micrometers. In certain embodiments, the openings may have a diameter of about 945 micrometers to 1385 micrometers. In one embodiment, the openings may have a diameter of greater than 2000 micrometers. In certain embodiments, the diameters of all openings are substantially the same (e.g., nominally the same within manufacturing tolerances). As used herein, the "diameter" of an opening is the maximum distance between the vertices of any pair of openings.

The repeating unit cells 810 are interconnected with each other at corresponding connection interfaces 826, so that the auxiliary material 800 is in the form of a lattice structure having predefined compressed regions 830 and predefined uncompressed regions 840, as shown more clearly in FIG. 8C. Although the predefined compressed regions 830 and the predefined uncompressed regions 840 may have various configurations, in this illustrated embodiment, the predefined compressed regions 830 are defined by the unit cells 810, and the predefined uncompressed regions 840 are in the form of voids 845 defined between the unit cells 810. In this embodiment, each void 845 is formed between four adjacent interconnected unit cells 810. For example, as shown in FIG. 8F, void 845a is defined between four adjacent unit cells 810a, 810b, 810c, 810d. Thus, the spaces existing between adjacent unit cells define predefined uncompressed regions. In other words, the uncompressed region 840 of the auxiliary material is not defined by the internal volume of the unit cell.

As described in more detail below, the structural configuration of the repeating unit cell may allow the unit cell to deform or buckle along its height H (see FIG. 9A) at different locations over a period of time while under an applied stress (e.g., until opposing sides of the inner surface of the cell contact each other). As a result, during such time, the unit cell may deform or buckle at a constant or substantially constant rate while under an applied stress (e.g., 30 kPa to 90 kPa). In other words, in certain embodiments, the structure of the repeating unit cell may lead to a stress plateau while the support material is under an applied stress, as shown, for example, diagrammatically in FIG. 11.

10A-10D show schematic diagrams of the compressive behavior of one repeating unit cell of FIGS. 8A-9B, e.g., unit cell 810, when under a range of applied stresses. In particular, the repeating unit cell 1010 is shown in a pre-compressed (undeformed) state in FIG. 10A, a first compressed state in FIG. 10B where each of the top and bottom portions 1012, 1014 of the unit cell 1010 begin to compress toward the middle portion 1016 of the unit cell 1010, causing the middle portion 1016 to begin to deflect, a second compressed state in FIG. 10C where the middle portion 1016 continues to deflect outward, and a densified state in FIG. 10D where the opposing sides 1018a, 1018b of the inner surface 1018 of the middle portion 1016 contact each other and the unit cell 810 reaches its solid height.

The relationship between the undeformed state U (Figure 10A), compressed states C1, C2 (Figures 10B-10C), and densified state D (Figure 10D) of the repeating unit cell 1010, and the stress-strain curve of the resulting auxiliary material are shown diagrammatically in Figure 11.

The stress-strain response of the auxiliary material begins with an elastic deformation (bending) characterized by a Young's modulus, for example, as the repeating unit begins to deform from its uncompressed state toward its first compressed state. This elastic deformation continues until a yield stress is reached. Once the yield stress is reached, a stress plateau may occur, for example, corresponding to progressive unit cell collapse due to elastic buckling, as the repeating unit cell continues to deform through its first and second compressed states. One skilled in the art will appreciate that the stress plateau depends at least on the nature of the material from which the unit cell is made. The stress plateau continues until densification, which indicates, for example, the collapse of the unit cells throughout the auxiliary material as the repeating unit cells reach their densified state, and thus the auxiliary material has reached its solid height.

Those skilled in the art will appreciate that the stress-strain curves for the auxiliary material will depend on a variety of factors, such as the uncompressed height, compositional configuration (including material properties), and/or structural configuration. By way of example, Table 1 below shows the stress-strain response for an exemplary auxiliary material compressed to a first compressed height (CH1) of 1.75 mm at an applied stress of 30 kPa, compressed to a second compressed height (CH2) of 0.75 mm at an applied stress of 90 kPa, and compressed to a third compressed height (CH3) of 0.45 mm at an applied stress of 90 kPa, varying only in uncompressed height (UH).

In another embodiment, the unit cell without repeating struts can be a modified Schwartz P structure. For example, the Schwartz P structure can be stretched in one or more directions to form a stretched Schwartz P structure, for example, as shown in FIG. 12A. Alternatively or additionally, in certain embodiments, the wall thickness of the Schwartz P structure can be thinned. For example, the Schwartz P structure can be stretched and thinned, as shown in FIG. 12B. In yet another embodiment, the Schwartz P structure can be cropped, for example, the height of the top portion H _T (see FIG. 9A) and/or the bottom portion H _B (see FIG. 9A) of the Schwartz P structure is reduced, as shown in FIG. 12C. Alternatively, or in addition to the above exemplary modifications, additional openings can be added through the walls of the Schwartz P structure, for example, as shown in FIG. 12D, which can help densify the resulting support material.

The repeating pillarless unit cell can take the form of other TPMS structures. For example, as shown in FIG. 13A, a pillarless unit cell 1300 can be formed from a sheet diamond structure having a diamond minimal surface with a Schwartzian D-plane lattice structure. This particular minimal surface is called "diamond" because it has two intertwined congruent labyrinths, each with the shape of a tubular version of the diamond bonded structure. Schwartzian D is
It may be functionally expressed as sin (x) sin (y) sin (z) + sin (x) cos (y) cos (z) + cos (x) sin (y) cos (z) + cos (x) cos (y) sin (z) = 0.
An exemplary support 1310 formed with a repeating unit cell 1300 and therefore a sheet diamond structure is shown in FIG. 13B.

In another embodiment, the pillarless based unit cell 1400 can be a gyroid structure, as shown in FIG.
It may be expressed functionally as sin(x)cos(y)+sin(y)cos(z)+sin(z)cos(x)=0.
An exemplary support material 1410 formed with a repeating unit cell 1500 and therefore a gyroscopic structure is shown in FIG. 14B. In other embodiments, the pillar-free based unit cell may be in the form of a cosine structure 1500 (FIG. 15A), or a coke can structure 1600 (FIG. 16A), each of which is defined by a curved minimal surface. Exemplary support materials 1510, 1610 formed with respective repeating unit cells 1500 (cosine structure), 1600 (coke can structure) are shown in FIG. 15B and FIG. 16B.

Edge Conditions In some embodiments, certain strutless-based unit cells, when interconnected to form the support material, may create undesirable edge conditions for tissue stapling. For example, as tissue slides across the support material during use, edge conditions may interact with the tissue to cause at least a portion of the support material to prematurely separate from the staple cartridge. These edge conditions may be the result of the geometry (e.g., substantially planar (e.g., planar within manufacturing tolerances) vs. non-planar outer surfaces) and the interconnectivity of the strutless-based unit cells that make up the support material. Thus, to ameliorate these edge conditions and thus inhibit premature separation of the support material, an outer layer having a different geometry may be positioned on one or more tissue-contacting surfaces of the support material.

9A-9B, as described above, the Schwartz P structures 810 have non-planar outer surfaces that form arcuate sides 821 that extend between the connection interfaces 826 of the unit cells 810. As a result, when the Schwartz P structures 810 are interconnected to form a support, such as the support 800 of FIGS. 8A-8F, the tissue contacting surface can have planar and non-planar surfaces, such as the tissue contacting surface 802 of FIGS. 8A-8B. This is a result of the structural configuration of at least the top portion 812 of each unit cell 810 (e.g., the exposed top outer surface 827a and the arcuate sides 821 of the top portion 812) and the spaced apart relationship therebetween. Thus, the edge conditions of the support material may be minimized by applying an outer layer having a generally planar (e.g., planar within manufacturing tolerances) geometry positioned over at least one otherwise tissue-contacting surface of the support material, such as tissue-contacting surface 802 of support material 800 in FIGS. 8A-8F. This may in turn reduce tissue loads (applied stresses) on the support material during deployment of the stapling device. Additionally, this may ease the attachment requirements between the support material and the cartridge.

The outer layer can have a variety of configurations, in some embodiments the outer layer can be formed of one or more planar arrays of struts (Figures 17A-17C), while in other embodiments the outer layer can be in the form of a film (Figure 18).

17A-17C show an exemplary support material 1700 having a first lattice structure 1702 formed of interconnected repeating unit cells 1704 and at least one planar array 1706, 1708. Each unit cell 1704 is similar to the unit cell 810 of FIGS. 9A-9B, and therefore common features will not be described in detail herein. In this illustrated embodiment, there are two planar arrays 1706, 1708, with the first planar array 1706 (e.g., in the YZ plane) extending across the top tissue-facing surface 1712 of the first lattice structure 1702 and the second planar array 1706 (e.g., in the XZ plane) extending across at least one side tissue-facing surface 1714 of the first lattice structure 1702. In other embodiments, the first or second planar arrays 1706, 1708 may be omitted. In further embodiments, the support material 1700 may include additional planar arrays.

The planar arrays 1706, 1708 can have a variety of configurations, but in this illustrated embodiment, the first and second planar arrays 1706, 1708 each include longitudinal struts 1716 that are parallel to and extend along the longitudinal axis ( _LA ) of the support material 1700. Although not shown, it is contemplated that additional struts may be added to the first and second planar arrays 1706, 1708. For example, in one embodiment, the first and/or second planar arrays 1706, 1708 may include intersecting struts that extend at an angle to the longitudinal axis and intersect the first and/or second longitudinal struts, thereby creating a repeating X-pattern.

In use, when the support material 1700 is releasably held on a cartridge, such as cartridge 200 of FIGS. 1-2C, the support material 1700 overlaps the rows of staples disposed within the cartridge. As a result, the first planar array 1706 can add to the final solid height of the support material 1700, thus accelerating its densification. However, to minimize impact, the first planar array 1706 may have a densification, and the first planar array 1706 may be designed such that it does not overlap the rows of staples. For example, as shown in FIGS. 17A-17C, the first planar array 1706 is divided into four spaced apart portions 1706a, 1706b, 1706c, 1706d such that three gaps 1718, 1720, 1722 are formed therebetween and along the longitudinal axis ( _LA ) of the support material 1700. As shown in FIG. 17C, these three gaps 1718, 1720, 1722 can align with three staple rows 1724, 1726, 1728 of a cartridge (not shown) such that the first planar array 1706 will not be captured, or will be minimally captured, by staples during deployment.

As noted above, in some embodiments, the absorbent film may be positioned on at least a portion of at least one of the non-planar tissue-facing surfaces of the lattice structure, thereby substantially preventing the tissue from prematurely separating the support from the cartridge as the tissue slides across the support. That is, the absorbent film may minimize edge conditions, and therefore reduce friction, that would otherwise be present on the tissue-contacting surface of the support.

18 illustrates an exemplary embodiment of an auxiliary material 1800 disposed on a cartridge 1801. The auxiliary material 1800 includes a lattice structure 1802 having an absorbent film 1804 disposed over at least a portion thereof. The lattice structure 1802, similar to the lattice structure of the auxiliary material 800 of FIG. 8A, is formed of interconnected repeating unit cells 1806, each of which is similar to the unit cells 810 of FIGS. 9A-9B, and therefore common features will not be described in detail herein. As shown, the absorbent film 1804 is disposed on all tissue-facing surfaces of the lattice structure 1802, which in this illustrated embodiment includes an upper tissue-facing surface 1808 (e.g., extending in the x-direction), a first longitudinal side 1810a (e.g., extending in the z-direction), a second opposing longitudinal side 1810b, a first lateral side 1812a (e.g., extending in the y-direction), and a second opposing lateral side (obstructed). In other embodiments, the absorbent film is not disposed on all tissue-facing surfaces of the lattice structure, e.g., the first lateral side and/or the second lateral side.

The absorbent film may have a variety of configurations. For example, in some embodiments, the absorbent film is designed to have a thickness that nominally affects densification of the support material when the support material is under applied stress and/or is formed of one or more materials that help reduce friction of the tissue contact layer for tissue manipulation. In some embodiments, the absorbent film may have a thickness of about 15 micrometers or less, e.g., about 5 micrometers to 15 micrometers, or about 8 micrometers to 11 micrometers. In one embodiment, the absorbent film may be formed of polydioxanone.

Attachment Features In some embodiments, the postless-based support material includes one or more attachment features extending at least partially along the length of the support material and configured to engage the staple cartridge, thereby retaining the support material on the cartridge prior to staple deployment. The one or more attachment features can have a variety of configurations. For example, the one or more attachment mechanisms can be channel attachments (FIGS. 19A-21), (FIGS. 22A-22B), configured to engage (e.g., press-fit or snap-fit) with an elongated cutting slot formed between opposing longitudinal edges of the elongated cutting slot in the staple cartridge, and/or end attachments (FIGS. 24-25) configured to engage with recessed end channels defined within the staple cartridge. Other than the differences discussed in detail below, the support material 1900, 2000, 2100, 2200 is substantially similar to the support material 800 of FIGS. 8A-8F, and thus the common features will not be described in detail herein.

In some embodiments, the channel attachment portion can include one or more compressible members structurally configured to be inserted into a longitudinal slot of the staple cartridge to engage opposing walls of the longitudinal slot. In certain embodiments, the one or more compressible members can include, for example, compressible openings extending longitudinally through the interior along the length of the cartridge contact surface of the support material.

19A-19B show an exemplary embodiment of a support material 1900 including a channel attachment 1910 having two compressible members 1912, 1914 interconnected by at least one common elongated joint 1916. The two compressible members 1912, 1914 can have a variety of configurations, but in this illustrated embodiment, each compressible member 1912, 1914 is in the form of an elongated rod having a triangular cross-sectional shape across its width (e.g., in the y-direction), but has a hollow triangular channel 1912a, 1914a extending through its interior along its length (e.g., in the z-direction). As shown, the two elongated rods 1912, 1914 are interconnected at corresponding vertices, thereby forming an elongated joint 1916 that defines a central connection region having a narrow thickness (e.g., in the x-direction). As shown in FIG. 19B, when the auxiliary material 1900 is disposed in a cartridge 1901 similar to the cartridge 200 of FIGS. 1-2C, at least one elongated joint 1916, and thus the central connection region, is positioned equidistant from the opposing walls 1903a, 1903b of the longitudinal slot 1903, as shown in FIG. 19. As a result, the central connection region is aligned with the advancement line of the cutting member, and thus may minimize or prevent the risk of the cutting member being jammed as it advances through the auxiliary material 1900 due to the narrow width of the central connection region. That is, the central connection region minimizes the additional auxiliary material that would otherwise need to be cut as the cutting member advances through the longitudinal slot 1903. Furthermore, the hollow triangular channels 1912a, 1914a reduce the amount of material on each side of the advancement line, which may minimize binding of the cutting edge of the auxiliary material to the cutting member as it advances further through the longitudinal slot 1903.

Although the overall width W _C of the channel attachment 1910 can vary, in this illustrated embodiment, the overall width W _C is greater than the width W _L of the longitudinal slot 1903 (e.g., the distance between the two opposing slot walls 1903 a, 1903 b). As a result, when the channel attachment 1910 is inserted into the longitudinal slot 1903, the compressible members deform and engage (e.g., are compressed against) the respective slot walls 1903 a, 1903 b due to the outward lateral forces created by the hollow triangular channels 1912 a, 1914 a. Thus, a press or friction fit is created between the compressible members 1912, 1914 and the respective slot walls 1903 a, 1903 b of the cartridge 1901.

The channel attachment portion may have other configurations (e.g., shapes and/or dimensions). For example, as shown in FIG. 20, the auxiliary material 2000 is similar to the auxiliary material 800 shown in FIGS. 8A-8X, except that the auxiliary material 2000 also includes a channel attachment portion 2010 in the form of an elongated protrusion extending outwardly from the cartridge contact surface 2004 of the auxiliary material 2000 and positioned between two inner rows of repeating unit cells 2010a, 2012a. The elongated protrusion 2010 is configured to be inserted into a longitudinal slot of a cartridge, such as the longitudinal slot 210 of the cartridge 200 of FIGS. 2A and 2C.

While the elongated projection 2010 can have a variety of configurations, in this illustrated embodiment, the elongated projection 2010 is formed from two compressible longitudinal rods 2010a, 2010b with a cross rod 2010c extending therebetween. In some embodiments, the width (e.g., in the y direction) of the elongated projection 2010 is greater than the width (e.g., the distance between two opposing slot walls) of the staple cartridge. As a result, when the elongated projection 2010 is inserted into a longitudinal slot, such as the longitudinal slot 210 of the cartridge 200 of FIGS. 2A-2C, the two longitudinal rods are configured to engage (e.g., compressed against) the opposing slot walls due to the outward lateral force created by the cross rod 2010c. Thus, a press or friction fit is formed between the elongated projection 2010 and the slot walls of the cartridge.

FIG. 21 illustrates another embodiment of the support material 2100 having a channel attachment. The support material 2100 is similar to the support material 2000 illustrated in FIG. 20, except that the channel attachment is in the form of separate protrusions 2110 (only two are shown in FIG. 21) spaced apart from one another along the longitudinal axis L _A of the support material 2100. The protrusions 2110 can have a variety of configurations, but in the illustrated embodiment, each protrusion 2110 is in the form of an annular boss having an elliptical shape. In other embodiments, the protrusions 2110 can be any other suitable shape and/or can differ in size/shape relative to one another. Each annular boss 2110 can be configured to be compressible, but in some embodiments can be dimensioned such that the width of each boss can be greater than the width of a longitudinal slot of a staple cartridge, such as the longitudinal slot 210 of the cartridge 200 of FIGS. 2A-2C (e.g., the distance between two opposing slot walls). As a result, when the separate annular bosses 2110 are inserted into the longitudinal slots of the cartridge, their outer surfaces 2110a are configured to engage (e.g., be compressed against) the opposing slot walls due to the outward radial force of the annular bosses 2110. Thus, a press or friction fit is formed between the annular bosses 2110a and the slot walls of the longitudinal slots.

Alternatively or additionally, in some embodiments, the support material may include edge attachment features configured to engage with corresponding edge attachment features of the support material. For example, as shown in FIGS. 22A-22C, the support material 2200 may include three sets of opposing clips 2202a, 2202b, 2204a, 2204b, 2206a, 2206b, each of which extends laterally outwardly and away from opposing outer surfaces 2200a, 2200b of the support material 2200. The three sets of clips 2202a, 2202b, 2204a, 2204b, 2206a, 2206b can have a variety of configurations, but in this illustrated embodiment, the three sets of clips 2202a, 2202b, 2204a, 2204b, 2206a, 2206b each have a hook-shaped configuration that engages with a respective edge attachment feature 2208a, 2208b, 2210a, 2210b, 2212a, 2212b of the cartridge 2201. In this illustrated embodiment, each edge attachment feature 2208a, 2208b, 2210a, 2210b, 2212a, 2212b has an inverted L-shaped configuration, thereby creating a flange that extends laterally outward from the staple cartridge 2201 (only one flange is shown in detail in FIGS. 22B-22C).

22C illustrates the engagement of one clip 2204a of the support material 2200 with one flange 2210a of the cartridge 2201. For simplicity, the repeating unit cells of the support material 2200 have been omitted. As shown, the inner surface 2214a of the end portion 2214 of the clip 2204a engages the outer bottom surface 2216 of the flange 2210a, thereby causing a portion of the outer surface 2218 of the flange 2210a to nest against a corresponding portion of the inner surface 2220 of the clip 2204a (e.g., male/female engagement). Additionally, as shown in FIG. 22C, the flange 2210a is biased outward, such that a portion of the outer surface 2218 of the flange 2210a is pressed against a corresponding portion of the inner surface 2220a of the clip 2204a when engaged.

Figures 23A-23B show another embodiment of a support having three sets of opposing clips 2302a, 2302b (partially occluded), 2304a, 2304b (partially occluded), 2306a, 2306b (partially occluded) configured to engage a corresponding set of opposing receiving members 2308, 2310 (partially occluded), 2312, 2314 (partially occluded), 2316, 2318 (partially occluded) of the staple cartridge 2301.

In this illustrated embodiment, each clip is structurally identical and has an inverted T-shaped configuration. Additionally, as shown, each set of receiving members is structurally identical and includes two inverted L-shaped members spaced apart and facing each other to form a T-shaped gap therebetween. By way of example, the engagement of one clip 2302a with its corresponding set of receiving members 2308a, 2308b is shown in more detail in FIG. 23B. As shown, the lateral segments 2316a, 2316b (e.g., extending in the z-direction) of clip 2302a are configured to engage with respective inner surfaces of each L-shaped member 2308a, 2308b (only one inner surface 3118 is shown), and the vertical segment 2320 (e.g., extending in the x-direction) of clip 2302a is configured to be positioned between two opposing surfaces of L-shaped members 2308a, 2308b (only one opposing surface 2322 is shown). Thus, the vertical segment 2320 can help maintain longitudinal alignment of the support material 2300 with respect to the staple cartridge 2301 and thus the staples (not shown) disposed therein. During use, the vertical segment 2320 can also help prevent premature disengagement of the clip 2302a from the corresponding set of receiving members 2308a, 2308b, and thus premature disengagement of the support material 2300 from the cartridge 2301.

Alternatively or additionally, in some embodiments, the support material may include end attachment features, such as opposing proximal and distal sets of bosses configured to engage (e.g., press-fit) corresponding proximal and distal sets of recesses defined in the staple cartridge. For example, in one embodiment, the support material may have rectangular bosses configured to engage the proximal and distal sets of rectangular recesses 2402a, 2402b, 2404a, 2404b of the staple cartridge 2400 of FIG. 24. In another embodiment, the support material may have circular bosses configured to engage the proximal and distal sets of circular recesses 2502a, 2502b, 2504a, 2504b of the staple cartridge 2500 of FIG. 25.

As noted above, in certain embodiments, the staple cartridge may include surface features in the form of recessed channels, such as recessed channels 216, 218, 220, as shown in FIGS. 2A and 2C. In such embodiments, the support material may be designed to engage the recessed channels to provide a releasable attachment mechanism between the support material and the staple cartridge, even when the frequency of staples in a longitudinal staple row (e.g., number of staples per length of the staple row) is different (e.g., greater) than the frequency of repeating unit cells in a corresponding longitudinal unit cell row (e.g., number of repeating unit cells per length of the cell row).

26A-26C show a support material 2600 disposed on a staple cartridge 2602 that is similar to the staple cartridge 200 of FIGS. 2A-2C, and therefore the common features will not be described in detail herein. The staple cartridge 2602 includes staple cavities 2604a, 2604b, 2604c, 2606a, 2606b, 2606c arranged in longitudinal rows and recessed channels surrounding each staple cavity 2604a, 2604b, 2604c, 2606a, 2606b, 2606c. As shown, a first recessed channel 2608 surrounds each of the first staple cavities 2604a, 2606a, a second recessed channel 2610 surrounds each of the second staple cavities 2604b, 2606b, and a third recessed channel 2612 surrounds each of the third staple cavities 2604c, 2606c. The first, second, and third recessed channels each include a respective floor 2614, 2616, 2618 at a respective height (e.g., extending in the x-direction) from the top surface 2602a of the staple cartridge 2602. In this illustrated embodiment, the respective heights are the same, although in other embodiments, the respective heights may differ.

While the support material 2600 can have a variety of configurations, in this illustrated embodiment, the support material 2600 is formed with repeating unit cells 2620 and attachment features 2622 extending from at least a portion of the plurality of unit cells 2620. The attachment features 2622 are each configured to insert into and engage at least a portion of the recessed channels 2608, 2610, 2612 of the staple cartridge 2602, thereby retaining the support material 2600 to the cartridge 2602 prior to staple deployment.

The attachment features 2622 can have a variety of configurations, with each attachment feature having a different geometry such that each attachment feature can engage with a respective recessed channel. This difference in geometry is due to the difference in frequency of the unit cells compared to the frequency of the staples 2605 in the staple cavities 2604a, 2604b, 2604c, 2606a, 2606b, 2606c of the staple cartridge 2602. Thus, the attachment features 2622 are positioned on each unit cell 2620 at predefined locations that correspond to the recessed channels 2608, 2610, 2612. As shown in FIG 26A and in more detail in FIGS. 26B-26C, which show only one half (e.g., the left half) of the support material 2600, the geometry of each of the attachment features 2622 is configured to engage with apexes 2608a, 2610a, 2610b, 2612a of respective recessed channels 2608, 2610, 2612 that point laterally outward relative to the longitudinal axis L _A of the staple cartridge 2602. In other embodiments, the geometry of the attachment features can be configured to engage other portions of the recessed channels.

The geometry of the attachment features 2622 can vary laterally and/or longitudinally relative to the longitudinal axis of the cartridge. The geometric variation depends at least on the frequency of the unit cells 2620 relative to the frequency of the staples 2605 and the shape of the staple cavities 2604a, 2604b, 2604c, 2606a, 2606b, 2606c. For example, the attachment features 2622 can vary in at least one of height (e.g., x-direction), width (e.g., y-direction), length (e.g., z-direction), and shape relative to one another. For example, as shown in FIG. 26B, the height _H1 of the first attachment feature 2622a extending from the first repeat unit cell 2620a is greater than the height _{H2 of the second attachment feature 2622b extending from the second repeat unit cell 2620b, and thus the heights of the first and second attachment features 2622a, 2622b differ laterally relative to the longitudinal axis L1 of the cartridge 2602. In this illustrated embodiment, as further shown in FIGS .} 26A and 26B, the shape of each of the first and second attachment features 2622a, 2622b also differs laterally relative to the longitudinal axis _L1 of the cartridge 2602. The first attachment feature 2622a has a cylindrical configuration and the second attachment feature 2622b has an arcuate configuration. Alternatively or additionally, the lengths of two or more of the attachment features may differ along the longitudinal axis _L1 of the cartridge 2602. 26A, third and fourth repeat unit cells 2620c, 2620d include third and fourth attachment features 2622c, 2622d, respectively, that differ in length and shape along the longitudinal axis L _A of the cartridge 2602 (e.g., extending in the z-direction). In this illustrated embodiment, the third attachment feature 2622c has a cylindrical configuration, while the fourth attachment feature 2622d has a triangular configuration.

In certain embodiments, the lateral variation in shape and/or height of the mounting features may correspond to the lateral variation in the recessed channel. For example, although not shown, in some embodiments, the walls of at least a portion of the recessed channel may extend at an angle to the longitudinal axis of the cartridge, and one or more of the resulting mounting features may vary in shape and/or height to correspond to the walls. In other embodiments, the length of the recessed channel may vary laterally, and one or more of the mounting features may vary in shape and/or height to correspond to the channels.

Unit Cell Frequency A non-strut-based support material may vary in thickness longitudinally (e.g., its length, e.g., z-direction) and/or laterally (e.g., its width, e.g., y-direction) such that the frequency of the staples in a longitudinal staple row (e.g., the number of staples per length of the staple row) is different (e.g., greater) than the frequency of the repeating unit cells in a corresponding longitudinal unit cell row (e.g., the number of unit cells per cell row), such that the staple legs of each staple may advance through different portions of the support material with each portion having a relative thickness difference, as shown in FIG.

27 illustrates an exemplary embodiment of a stapling assembly 2700 having a staple cartridge 2702, such as staple cartridge 200 of FIGS. 1-2C , with staples arranged in a longitudinal row (only four staples 2704, 2706, 2708, 2710 of a portion of a first longitudinal staple row 2712 are shown). Support material 2714 is disposed on a top surface 2702a of the staple cartridge 2702. The support material 2714 includes interconnected repeating strutless unit cells, such as repeating unit cell 810 of FIGS. 8A-9C (only five repeating unit cells 2716a, 2716b, 2716c, 2716d, 2716e are shown), which are arranged in a longitudinal row (only a portion of the illustrated first longitudinal row of unit cells 2717 is shown). As shown, the first longitudinal row of units 2717 overlaps with the first longitudinal row of staples 2712 such that the frequency of the staples 2704, 2706, 2708, 2710 is different (e.g., non-multiple) from the frequency of the unit cells 2716a, 2716b, 2716c, 2716d, 2716e such that each staple leg 2704b, 2706a, 2706b, 2708a, 2708b, 2710a of each staple 2704, 2706, 2708, 2710 aligns with and penetrates a different respective portion 2718, 2720, 2722, 2724, 2726 of the first longitudinal row of unit cells 2712 and thus the support material 2714 when the support material 2714 is stapled to tissue, for example. Further, as shown in FIG. 27, due to the structural configuration of the repeating unit cells 2716a, 2716b, 2716c, 2716d, 2716e (e.g., not generally square), at least two or more of these different portions 2718, 2720, 2722, 2724, 2726, 2728 have different relative thicknesses _T1 , _T2 , _T3 , _T4 , _T5 (e.g., thick vs. thin), and thus the thickness of the auxiliary material 2714 captured within the fired staples will vary between adjacent staples stapled to consistent tissue.

In some embodiments, the difference in relative thickness of the auxiliary material may be paired with a corresponding difference in staple leg length. For example, the legs of any staple configured to advance through a thicker portion of the auxiliary material may be longer in length than the legs of any staple configured to advance through a thinner portion of the auxiliary material when the staple and unit cell frequencies are the same. Alternatively or additionally, the difference in relative thickness may be paired with a corresponding difference in anvil pocket depth, or with a difference in tissue gap between a first staple leg and a second staple when the staple drivers are at the same height.

Figure 28A illustrates an exemplary embodiment of a stapling assembly 2800 that is similar to the stapling assembly 2700 of Figure 27, except that the structural configuration of the support material 2801 has been modified such that the staple and unit cell frequencies are the same, such that the first staple legs 2804a, 2806a, 2808a of each staple 2804, 2806, 2808 are configured to pass through a respective portion of the support material 2801 having the same first thickness _T1 , and the second staple legs 2804b, 2806b, 2808b of each staple 2804, 2806, 2808 are configured to pass through a respective portion of the support material 2801 having the same second thickness _T2 . As shown, the first thickness _T1 is greater than the second thickness _T2 and therefore the first leg length _L1 may be greater than the second leg length _L2 for each staple 2804, 2806, 2808 to offset the thickness difference. In this illustrated embodiment, the crowns 2804c, 2806c, 2808c of each staple 2804, 2806, 2808 have a non-planar configuration (e.g., a step-up configuration) to provide the staple leg length difference. Furthermore, when the staples 2804, 2806, 2808 are deployed and the support material 2801 is stapled to the tissue T, as shown in FIG. 28B, each staple has two distinct formed staple heights _H1 , _H2 . FIG. 29 shows another exemplary embodiment of a staple fastening assembly 2900 that is similar to staple fastening assembly 2800, except that the crowns 2904c, 2906c, 2908c of each staple 2904, 2906, 2908 are generally planar (e.g., generally straight or linear within manufacturing tolerances) such that the formed height of the first staple is generally uniform (e.g., nominally the same within manufacturing tolerances).

As described above, the support material may include a lattice structure (e.g., defined by planar interconnected struts) formed of strut-based unit cells. Generally, such a support material may include a tissue contacting layer, a cartridge contacting layer, and an internal structure (e.g., a buckling structure). The internal structure generally includes struts (e.g., spacer struts) that connect the tissue contacting layer and the cartridge contacting layer together in a spaced apart relationship. These struts may be configured to collapse without contacting each other while the support material compresses under stress. As a result, densification of the support material may be delayed and therefore may occur at higher strains.

The tissue contact layer and the cartridge contact layer may have various configurations. In some embodiments, at least one of the tissue contact layer and the cartridge contact layer may include a plurality of struts that define the openings. In some embodiments, both the tissue contact layer and the cartridge contact layer are generally planar (e.g., planar within manufacturing tolerances). The tissue contact layer and the cartridge contact layer may be oriented parallel to one another along a longitudinal axis that extends from the first end to the second end of the support material and may further define a vertical axis extending therebetween.

The struts can have a variety of configurations. For example, in some embodiments, the struts can have a generally uniform cross-section (e.g., uniform within manufacturing tolerances), while in other embodiments, the struts can have different cross-sections. In some embodiments, the support material can have an average strut thickness in the range of about 0.1 mm to 0.5 mm, about 0.1 mm to 0.4 mm, or about 0.1 mm to 0.3 mm.

30A-30B show an exemplary strut-based support material 3000. The support material 3000 includes a tissue contact layer 3002, a cartridge contact layer 3004, and an internal structure 3006 extending therebetween. The internal structure 3006 is configured to collapse (compress) while the support material 3000 is under an applied stress, thus causing the support material 3000 to compress when stapled to tissue.

The tissue contacting layer 3002 and the cartridge contacting layer 3004 may have various configurations, but in the illustrated embodiment, both are generally planar (e.g., planar within manufacturing tolerances). Furthermore, the tissue contacting layer 3002 and the cartridge contacting layer 3004 are parallel to each other along a longitudinal axis ( _LA ) that extends from the first end 3000a to the second end 3000b of the support material 3000. As shown, the tissue contacting layer 3002 and the cartridge contacting layer 3004 are inverted images of each other, and the thickness ( _TC ) of the cartridge contacting layer 3004 is greater than the thickness ( _TT ) of the tissue contacting layer 3002. Thus, for simplicity, the following description is for the tissue contacting layer 3002. However, one skilled in the art will understand that the following discussion is also applicable to the cartridge contacting layer 3004.

The tissue contact layer 3002 has first, second, and third longitudinal struts 3008a, 3010a, 3012a parallel to the longitudinal axis (L) of the support material 3000, with the second longitudinal strut 3010a positioned between and spaced apart from the first and third longitudinal struts 3008a, 3012a. The tissue contact layer 3002 also includes a first cross strut 3014a and a second cross strut 3016a. Each of the first cross struts 3014a is connected to the first and second longitudinal struts 3008a, 3010a. The first cross strut 3014a may be oriented in a variety of different positions, but in this illustrated embodiment, the first cross strut 3014a is oriented orthogonally to the first and second longitudinal struts 3008a, 3010a. Similarly, each of the second cross struts 3016a is connected to the second and third longitudinal struts 3010a, 3012a. The second cross strut 3016a may be oriented in a variety of different positions, but in the illustrated embodiment, the second cross strut 3016a is oriented orthogonally to the second and third longitudinal struts 3010a, 3012a. Additionally, as shown, the first cross strut 3014a is aligned with the second cross strut 3016a in the y-direction.

Additionally, the first cross struts 3014a are spaced longitudinally from one another by a first distance _D1 , and the second cross struts 3014a are spaced longitudinally from one another by a second distance _D2 . As a result, an opening 3018a is created in the tissue contacting layer 3002. The opening 3018a can have a variety of sizes and shapes, however, in this illustrated embodiment, _D1 and _D2 are equal or substantially equal and thus, in combination with the orientation of the first and second cross struts 3014a, 3016a, the resulting opening 3018a is in the form of a rectangle having generally uniform (e.g., nominally the same within manufacturing tolerances) dimensions.

While the internal structure 3006 can have a variety of configurations, in this illustrated embodiment, the internal structure 3006 includes spacer posts 3020 that extend between the tissue contacting layer 3002 and the cartridge contacting layer 3004. The spacer posts 3020 include a first set of angled posts 3022a, 3022b and a second set of angled posts 3024a, 3024b, each of which extends at an angle (e.g., 45 degrees) relative to the tissue contacting layer 3002 and the cartridge contacting layer 3004. The first set of angled struts includes a first angled strut 3022a that extends from a first longitudinal strut 3008a of the tissue contacting surface 3002 to a second longitudinal strut 3010b of the cartridge contacting layer 3004, and a second angled strut 3022b that extends from the first longitudinal strut 3008b of the cartridge contacting layer 3004 to the second longitudinal strut 3010a of the tissue contacting layer 3002. As a result, the first and second angled struts 3022a, 3022b alternate along the length (L) of the support material. The second set of alternating angled struts includes a third angled strut 3024a and a fourth angled strut 3024b. The third angled strut 3024a is similar to the first angled strut 3022a except that the third angled strut 3024a extends from the second longitudinal strut 3010a of the tissue contacting layer 3002 to the third longitudinal strut 3012b of the cartridge contacting layer 3004. The fourth angled strut 3024b is similar to the second angled strut 3022b except that the fourth angled strut 3024b extends from the second longitudinal strut 3010b of the cartridge contacting layer 3004 to the third longitudinal strut 3012a of the tissue contacting layer 3002. As a result, in this illustrated embodiment, the first and third angled struts 3022a, 3024a extend in the same direction relative to each other, and the second and fourth angled struts 3022b, 3024b extend in the same direction relative to each other.

As further shown in FIG. 30A , an opening 3018b is created in the cartridge contact layer 3004 between the first cross strut 3014b and the second cross strut 3016b. Additionally, the angled struts 3022a, 3022b, 3024a, 3024b substantially overlap at least the corresponding opening 3018b in the cartridge contact layer 3004, which, as described above, has a thickness T _C that is greater than the thickness T _T of the tissue contact layer 3002. Thus, the opening 3018b defined in the cartridge contact layer 3004 can be configured to receive at least a portion of the corresponding angled strut as it flexes while the support material 3000 is compressed under an applied stress. This creates additional space within the internal structure 3006 for buckling, thus reducing the solid height of the support material 3000. As a result, during use, densification of the auxiliary material 3000 can be delayed so that the auxiliary material 3000 can undergo a wider range of deformation without reaching its solid height.

Furthermore, by alternating the angled struts 3022a, 3022b, 3024a, 3024b, a concentration zone 3030 is created in the internal structure 3006. As shown, this concentration zone 3030 extends longitudinally along the support material between the first and second sets of angled struts 3022a, 3022b, 3024a, 3024b. As a result, as shown in more detail in FIG. 30B, none of the struts 3020 in the internal structure 3006 overlap with this concentration zone 3030. In other words, this concentration zone 3030 is designed to be a space that does not include any struts that do not cross before or during compression of the support material. Thus, the presence of this concentration zone 3030 may increase the high density points of the support material 3000 while the support material is stapled to the tissue (e.g., reducing the solid height of the support material). Additionally, the concentration zone may overlap the cut line of the auxiliary material, thus reducing the amount of material along the cut line. This helps to facilitate the advancement of the cutting element of the stapling device, thus facilitating the cutting of the auxiliary material.

31A, 32A, 33A, and 34A show various other exemplary strut-based support materials 3100, 3200, 3300, and 3400. Each exemplary support material has a lattice structure formed from repeating interconnected strut-based unit cells, which are shown in more detail in FIGS. 31B-31D, 32B-32D, 33B-33E, and 34B-34E. These support materials are structured to compress when exposed to compressive forces (e.g., stresses applied when stapled to tissue).

31A shows another exemplary support material 3100 in the form of a lattice structure including a top portion 3102, a bottom portion 3104, and an internal structure 3106 extending therebetween. The top portion 3102 is configured to contact tissue and thus forms the tissue contact layer of the support material 3100, while the bottom portion 3104 is configured to attach to a cartridge and thus forms the cartridge contact layer of the support material 3100. The internal structure 3106 may be configured to be compressed to a deformed state under a load, for example, when stapled to tissue. The lattice is formed of an array of repeating unit cells 3110, one of which is shown in more detail in FIGS. 31B-31D. Thus, for brevity, the following description is for the top portion 3102, bottom portion 3104, and internal structure 3106 of one unit cell.

The top portion 3102 and the bottom portion 3104 can have a variety of configurations, but in the illustrated embodiment, the top portion 3102 and the bottom portion 3104 are inverted images of one another, and therefore, for brevity, the following description is directed to the top portion 3102 of one unit cell 3110. However, one of ordinary skill in the art will appreciate that the following discussion is also applicable to the bottom portion 3104.

As shown in Figures 31A-31D, the upper portion 3102 includes first and second cross struts 3112, 3114 and first and second angled struts 3116, 3118 extending therebetween. In this illustrated embodiment, the first angled strut 3116 extends from a first end of the first cross strut 3112 at a first angle and terminates at a central portion of the second cross strut 3114, and the second angled strut 3118 extends from a second opposite end of the first cross strut 3112 at a second angle and terminates at a central portion of the second cross strut 3114. As a result, the first and second angled struts 3116, 3118 converge and connect at a central segment 3114a of the second cross strut 3114. In other embodiments, the first and second angled struts 3116, 3118 may extend at any other suitable angle.

Although the internal structure 3106 can have a variety of configurations, in this illustrated embodiment, the internal structure 3106 includes three spacer struts 3120a, 3120b, 3120c. As shown in Figures 31B-31D, the first and third spacer struts 3120a, 3120c each interconnect a first cross strut 3112 of the top portion 3102 to a first cross strut 3112 of the bottom portion 3104, and the second spacer strut 3120b interconnects a central segment 3114a of a second cross strut 3114 of the top portion 3102 to a central segment 3114a of a second cross strut 3114 of the bottom portion 3104.

32A shows another exemplary support material 3200 in the form of a lattice structure including a top portion 3202, a bottom portion 3204, and an internal structure 3206 extending therebetween. The top portion 3202 is configured to contact tissue and thus forms the tissue contact layer of the support material 3200, while the bottom portion 3204 is configured to attach to a cartridge and thus forms the cartridge contact layer of the support material 3200. The support material 3200 is similar to the support material 3100 shown in FIGS. 31A-31D, except for the differences described below. The lattice is formed of an array of repeating unit cells 3201, one of which is shown in more detail in FIGS. 32B-32D. Therefore, for the sake of brevity, the following description is for the top portion 3202, bottom portion 3204, and internal structure 3206 of one unit cell.

As shown in Figures 32B-32D, the top portion 3202 is offset from the bottom portion 3204 in the first and second dimensions (X, Z). The top portion 3202 includes two separate sets of interconnected pillars 3202a, 3202b connected to each other via connecting pillars 3203. The bottom portion 3204 includes eight interconnected pillars 3204a, six of which form the first hexagonal face of the unit cell 3201. The internal structure 3206 includes two sets of spacer pillars 3208a, 3208b, 3208c, 3210a, 3210b, 3210c extending from the top portion 3202 to the bottom portion, thereby forming two additional hexagonal faces of the unit cell 3201, as shown in Figure 32B.

33A shows another exemplary support material 3300 in the form of a lattice structure including a top portion 3302, a bottom portion 3304, and an internal structure 3306 extending therebetween. The top portion 3302 is configured to contact tissue and thus forms the tissue contact layer of the support material 3300, while the bottom portion 3304 is configured to attach to a cartridge of a surgical stapler and thus forms the cartridge contact layer of the support material 3300. The support material 3300 is similar to the support material 3100 shown in FIGS. 31A-31D, except for the differences described below. The lattice is formed of an array of repeating unit cells 3310, one of which is shown in more detail in FIGS. 33B-33E. Thus, for the sake of brevity, the following description is for the top portion 3302, bottom portion 3304, and internal structure 3306 of one unit cell 3310.

The top portion 3302 and the bottom portion 3304 can have a variety of configurations, but in the illustrated embodiment, the top portion 3302 and the bottom portion 3304 are substantially identical to one another, and therefore, for brevity, the following description is directed to the top portion 3302 of one unit cell 3310. However, one of ordinary skill in the art will understand that the following discussion is also applicable to the bottom portion 3304.

As shown in Figures 33A-33E, the upper portion 3302 includes a first pair of opposing outer struts 3312a, 3312b and a second pair of opposing outer struts 3312c, 3312d. The first and second pairs of outer struts 3312a, 3312b, 3312c, 3312d are connected such that the upper portion 3302 is in the form of a parallelogram having four corners 3316a, 3316b, 3316c, 3316d. In this illustrated embodiment, the parallelogram is a square. The upper portion 3302 also includes a first cross strut 3318 connecting the first pair of opposing outer struts 3312a, 3312b and a second cross strut 3320 connecting the second pair of opposing outer struts 3312c, 3312d. As shown, the first and second cross struts 3318, 3320 cross at 90 degrees to each other in the center of the upper portion 3302.

While the internal structure 3306 can have a variety of configurations, in this illustrated embodiment, the internal structure 3306 includes a first side 3322a, a second adjacent side 3322b, a third side 3322c opposite the first side 3322a, and a fourth side 3322d opposite the second side 3322b (see FIG. 33D). Although each side can have a variety of configurations, in the illustrated embodiment, the first and third sides 3322a, 3322c are substantially identical to one another, and the second and fourth sides 3322b, 3322d are substantially identical to one another.

33B-33E, the first side 3322a of the internal structure 3306 includes first and second angled spacer struts 3324a, 3324b that extend in opposite directions from the central segment 3313 of the outer strut 3312a of the bottom portion 3304 to the first and second corners 3316a, 3316b, respectively, of the top portion 3302. Similarly, the third side 3322c of the internal structure includes third and fourth angled spacer struts 3326a, 3326b that extend in opposite directions from the central segment (interrupted) of the outer strut 3312b (interrupted) of the bottom portion 3304 to the third and fourth corners 3316c, 3316d, respectively, of the top portion 3302.

Additionally, the second side 3322b of the internal structure 3306 includes fifth and sixth angled spacer struts 3328a, 3328b extending in opposite directions from the central segment 3315 of the outer strut 3312c of the top portion 3302 to the first and fourth corners 3316a, 3316d of the bottom portion 3304. Similarly, the fourth side 3322d of the internal structure 3306 includes seventh spacer struts 3330a and eighth angled spacer struts (interrupted) extending in opposite directions from the central segment 3317 of the outer strut 3312d of the top portion 3302 to the second and third corners 3316b of the bottom portion 3304 (the third corner of the bottom portion 3304 is interrupted).

The internal structure 3306 also includes a first pair of angled spacer struts 3332a, 3332b. The first angled spacer strut 3332a extends from the center of the top portion 3302 to a central segment 3334 of the outer strut 3312c of the bottom portion 3304. Similarly, the second spacer strut 3332b extends from the center of the top portion 3302 to a central segment (interrupted) of the outer strut 3312d of the bottom portion 3304. Thus, the first pair of angled spacer struts 3332a, 3332b extend in opposite directions from the center of the top portion 3302.

Additionally, the internal structure 3306 includes a second pair of angled spacer posts 3336a, 3336b. The first angled spacer post 3336a extends from the center of the bottom portion 3304 to the center segment 3338 of the outer post 3312b of the top portion 3302. Similarly, the second spacer post 3336b extends from the center of the bottom portion 3304 to the center segment (interrupted) of the outer post 3312a of the top portion 3302. Thus, the second pair of angled spacer posts 3336a, 3336b extend in opposite directions from the center of the bottom portion 3304.

34A shows another exemplary support material 3400 in the form of a lattice structure including a top portion 3402, a bottom portion 3404, and an interior structure 3406 extending therebetween. The top portion 3402 is configured to contact tissue and thus forms the tissue contact layer of the support material 3400, while the bottom portion 3404 is configured to attach a surgical stapler to a cartridge and thus forms the cartridge contact layer of the support material 3400. The support material 3400 is similar to the support material 3100 shown in FIGS. 31A-31D, except for the differences described below. The lattice is formed of an array of repeating unit cells 3410, one of which is shown in more detail in FIGS. 34B-34E. Thus, for the sake of brevity, the following description is for the top portion 3402, bottom portion 3404, and interior structure 3406 of one unit cell.

The top portion 3402 and the bottom portion 3404 can have a variety of configurations, but in the illustrated embodiment, the top portion 3402 and the bottom portion 3404 are substantially identical to one another, and therefore, for the sake of brevity, the following description is for the top portion 3402 of one unit cell 3410. However, one of ordinary skill in the art will understand that the following discussion is also applicable to the bottom portion 3404.

As shown in Figures 34B-34E, the top portion 3402 includes four cross struts 3408a, 3408b, 3408c, 3408d that connect together in the center of the top portion 3402. Although the four cross struts 3408a, 3408b, 3408c, 3408d can connect together at different angles relative to one another, in this illustrated embodiment the four cross struts 3408a, 3408b, 3408c, 3408d connect at 90 degrees to one another, thus forming a cross having four outer ends 3411a, 3411b, 3411c, 3411d. The upper portion 3402 also includes four struts 3412a, 3412b, 3412c, 3412d connected to form a square having four corners 3414a, 3414b, 3414c, 3414d. Each strut 3412a, 3412b, 3412c, 3412d of the square intersects with a central segment 3416a, 3416b, 3416c, 3416d (see FIG. 34D) of one of the intersecting four struts 3408a, 3408b, 3408c, 3408d.

While the internal structure 3406 can have a variety of configurations, in this illustrated embodiment, the internal structure 3406 includes four sets of angled outer struts, with each set of angled outer struts including two angled struts 3418a, 3418b, 3420a, 3420b, 3422a, 3422b, 3424a, 3424b. The four sets of angled outer struts can have a variety of configurations. As shown, in this illustrated embodiment, the first and second sets of outer struts are mirror images of each other, and the third and fourth sets are mirror images of each other.

As shown in FIG. 34B, the first and second angled struts 3418a, 3418b of the first set of angled outer struts each extend in opposite directions from the first corner 3414a of the square of the bottom portion 3404 to one of the first and second corners 3411a, 3411b, respectively, of the intersection of the top portion 3402. Similarly, the first and second angled struts 3420a, 3420b of the second set of angled outer struts each extend in opposite directions from the third corner 3414c (obstructed) of the square of the bottom portion 3404 to one of the remaining corners (e.g., the third and fourth corners 3411c, 3411d, respectively) of the intersection of the top portion 3402.

As further shown in FIG. 34B, the first and second angled struts 3422a, 3422b of the third set of angled outer struts each extend in opposite directions from the second square corner 3414b of the top portion 3404 to one of the second and third corners 3411b, 3411c, respectively, of the intersection of the bottom portion 3404. Similarly, the first and second angled struts 3424a, 3424b of the fourth set of angled outer struts each extend in opposite directions from the fourth square corner 3414d of the top portion 3404 to one of the first corner 3411a and fourth corner 3411d (interrupted) of the intersection of the bottom portion 3404.

The internal structure 3406 also includes two sets of inner angled struts, each set including two angled struts 3426a, 3426b, 3428a, 3428b. The two sets of angled inner struts may have a variety of configurations. As shown in FIG. 34B, the first and second angled struts 3426a, 3426b of the first set of angled inner struts each extend in opposite directions from the center of the intersection of the top portion 3402 to one of the second corner 3414b and the fourth corner 3414d (interrupted) of the square of the bottom portion 3404. In this illustrated embodiment, the first and second angled struts 3428a, 3428b of the second set of angled inner struts are the inverse of the first and second angled struts 3426a, 3426b. That is, as shown in FIG. 34B, the first and second angled struts 3428a, 3428b of the second set of angled inner struts each extend in opposite directions from the center of the intersection in the bottom portion 3404 to one of the first corner 3414a and the third corner 3414c (obstructed) of the square in the top portion 3402.

As shown in Figures 30A-34E, the strut-based configuration of the support material creates multiple openings throughout the support material, thereby creating fewer barriers for cell infiltration compared to non-strut-based support material configurations. That is, these multiple openings may allow for a more rapid inflow of cells into the support material when the support material is stapled to tissue. This increased rate may thereby enhance tissue ingrowth compared to other support materials.

Although the openings in the top and bottom portions of the support material shown in Figures 31A-34E are regularly and symmetrically defined by the struts, in other embodiments, the top and bottom portions may alternatively be planar sheets having regular or irregular openings formed therein (e.g., "Swiss cheese" style), or non-planar (e.g., rippled or corrugated) sheets having regular or irregular openings formed therein. These openings in planar and non-planar support material configurations may also promote cellular in-growth within the support material when the support material is stapled to tissue.

In other embodiments, the repeating units of the strut-based support material may have other structural configurations. For example, FIG. 35 shows an exemplary strut-based unit cell 3500 that may be used to form the support material described herein. The unit cell 3500 includes a top portion 3502, a bottom portion 3504, and an interior structure 3506 extending therebetween.

The top and bottom portions 3502, 3504 may have a variety of configurations, but in the illustrated embodiment, the top and bottom portions 3502, 3504 are substantially identical to one another, and therefore, for the sake of brevity, the following description is for the top portion 3502. However, one of ordinary skill in the art will appreciate that the following discussion is also applicable to the bottom portion 3504.

As shown in FIG. 35, the upper portion 3502 includes a first pair of opposing outer struts 3512a, 3512b and a second pair of opposing outer struts 3514a, 3514b. The first and second pairs of outer struts 3512a, 3512b, 3514a, 3514b are connected such that the upper portion 3502 is in the form of a parallelogram having four corners 3516a, 3516b, 3516c, 3516d. In this illustrated embodiment, the parallelogram is a square. The upper portion 3502 also includes a first cross strut 3518 connecting the first pair of opposing outer struts 3512a, 3512b and a second cross strut 3520 connecting the second pair of opposing outer struts 3514a, 3514b. As shown, the first and second cross struts 3518, 3520 cross at 90 degrees to each other in the center of the upper portion 3502.

The internal structure 3506 may have a variety of configurations, but in this illustrated embodiment, the internal structure 3506 includes a first side 3522a, a second adjacent side 3522b, a third side 3522c opposite the second side 3522b, and a fourth side 3522d opposite the first side 3522a. Each side may have a variety of configurations, but in this illustrated embodiment, the first, second, third, and fourth sides 3522a, 3522b, 3522c, 3522d are different. In this illustrated embodiment, the fourth side 3522d does not include any spacer posts.

As shown in FIG. 35, the first side 3522a of the internal structure 3506 includes first and second angled spacer struts 3524a, 3524b extending parallel to one another. The first angled spacer strut 3524a extends from a first corner 3516a of the bottom portion 3504 to a central segment 3513a of the first outer strut 3512a of the top portion 3502, and the second angled spacer strut extends from a central segment 3513b of the first outer strut 3512a of the bottom portion 3504 to a second corner 3516b of the top portion 3502.

The second side 3522b of the internal structure 3506 includes third and fourth angled spacer struts 3526a, 3526b extending parallel to one another. The third angled spacer strut 3526c extends from the second corner 3516b of the bottom portion 3504 to the central segment 3515 of the second outer strut 3514b of the top portion 3502, and the fourth angled spacer strut 3526b extends from the central segment (interrupted) of the second outer strut (interrupted) of the bottom portion 3504 to the third corner 3516c of the top portion 3502.

Additionally, the third side 3522c of the internal structure 3506 includes fifth and sixth angled spacer struts 3528a, 3528b extending parallel to one another. The fifth angled spacer strut 3528a extends from the fourth corner 3516d of the bottom portion 3504 to the central segment 3517 of the second outer strut 3514a of the top portion 3502, and the sixth angled spacer strut 3528b extends from the central segment 3517 of the first outer strut 3514a of the bottom portion 3504 to the first corner 3516a of the top portion 3502.

The internal structure 3506 also includes two sets of internal angled struts. The first set includes three internal angled struts 3530a, 3530b, 3530c, each extending from the center of the top portion 3502 to the central segments 3513, 3517, 3519 of the outer struts 3512a, 3514a, 3512b, respectively, of the bottom portion 3504. Thus, in the first set, the first internal angled strut 3530a and the third internal angled strut 3530c extend in opposite directions, and the second internal angled strut 3530b extends in a different direction relative to the first and third internal angled struts 3530a, 3530c. The second set includes three internal angled struts 3532a, 3532b, 3532c, each extending from the center of the bottom portion 3504 to the central segments 3513, 3515, 3519 of the outer struts 3512a, 3514b, 3512b, respectively, of the top portion 3502. Thus, in the second set, the first internal angled strut 3532a and the third internal angled strut 3532c extend in opposite directions, and the second internal angled strut 3532b extends in a different direction relative to the first and third internal angled struts 3532a, 3532b.

In other embodiments, the repeating units of the strut-based support material may have other structural configurations. For example, FIG. 36 shows an exemplary strut-based unit cell 3600 that may be used to form the support materials described herein. The unit cell 3600 includes a top portion 3602, a bottom portion 3604, and an interior structure 3606 extending therebetween.

The top and bottom portions 3602, 3604 may have a variety of configurations, but in the illustrated embodiment, the top and bottom portions 3602, 3604 are substantially identical to one another, and therefore, for the sake of brevity, the following description is for the top portion 3602. In one embodiment, the bottom portion 3604 is an inverted image of the top portion 3602. However, one of ordinary skill in the art will appreciate that the following discussion is also applicable to the bottom portion 3604.

As shown in FIG. 36, the top portion 3602 includes a first pair of cross struts 3612a, 3612b and a second pair of cross struts 3612c, 3612d. The first and second pairs of cross struts 3612a, 3612b, 3612c, 3612d are connected such that the top portion 3602 is in the form of a sparse tetrahedron having five corners 3616a, 3616b, 3616c, 3616d, 3616e. The first pair of cross struts 3612a, 3612b intersect at intersection 3617 on the top portion. Cross strut 3612a connects to cross strut 3612c at corner 3616d, and cross strut 3612b connects to cross strut 3612d at corner 3616c. As shown, cross struts 3612a, 3612b cross at 90 degrees to each other in the center of upper portion 3602 at intersection 3617.

36, the internal structure 3606 includes first and second angled spacer struts 3620a, 3620b extending parallel to one another. The first angled spacer strut 3620a extends from a first corner 3616a of the top portion 3602 to a corner 3616e of the bottom portion 3604, and the second angled spacer strut 3620b extends from a third corner 3616c of the top portion 3602 to an intersection 3617 of the bottom portion 3604. Additionally, the internal structure 3606 includes third and fourth angled spacer struts 3622a, 3622b extending parallel to one another. The third angled spacer strut 3622a extends from the second corner 3616b of the top portion 3602 to the corner 3616e of the bottom portion 3604, and the fourth angled spacer strut 3622b extends from the fourth corner 3616d of the top portion 3602 to the intersection 3617 of the bottom portion 3604. Thus, the first angled spacer strut 3620a and the third angled spacer strut 3622a extend in opposite directions, and the second angled spacer strut 3620b and the fourth angled spacer strut 3622b extend in opposite directions.

Outer Layer In some embodiments, the support material may include a lattice structure (e.g., a first lattice structure or an internal lattice structure) extending from the top surface to the bottom surface and at least one outer layer, each having a different compression ratio (e.g., pre-compression height to compressed height). As a result, the compression characteristics of the lattice structure and the at least one outer layer may be different and therefore tailored to perform different functions (e.g., tissue ingrowth, cartridge connection, etc.), but in combination provide an overall compression profile of the support material that is desirable for different staple conditions and/or staple heights. For example, based on the resulting overall compression profile of the support material, the support material may be configured to undergo a strain in the range of about 0.1 kPa to 0.9 kPa while under an applied stress in the range of about 30 kPa to 90 kPa. In other embodiments, the strain can be in the range of about 0.1-0.8, about 0.1-0.7, about 0.1-0.6, about 0.2-0.8, about 0.2-0.7, about 0.3-0.7, about 0.3-0.8, about 0.3-0.9, about 0.4-0.9, about 0.4-0.8, about 0.4-0.7, about 0.5-0.8, or about 0.5-0.9.

The lattice structure and at least one outer layer may have a variety of configurations, but in some embodiments, the first lattice structure has a compression ratio greater than the compression ratio of the at least one outer layer. For example, in one embodiment, the first lattice structure may be configured to compress in a range of about 3 mm to 1 mm while under an applied stress, and thus have a compression ratio of 3, while at least the outer layer may be configured to compress in a range of about 2 mm to 1 mm while under the same applied stress, and thus have a compression ratio of 2.

In certain embodiments, the auxiliary material may include an outer layer in the form of a second lattice structure or an absorbent film positioned on at least a portion of the top surface of the first lattice structure and configured to be positioned against tissue. This outer layer may be configured to promote tissue ingrowth within the auxiliary material and/or create a smooth or substantially smooth tissue contact surface that may easily slide against tissue, thus lowering tissue loads (applied stresses) on the auxiliary material during placement of the stapling device and/or facilitating attachment requirements between the auxiliary material and the cartridge. Alternatively or additionally, the auxiliary material may include an outer layer in the form of a film or a third lattice structure positioned on at least a portion of the bottom surface of the first lattice structure and configured to be positioned against the cartridge. This outer layer may thus be configured to attach the auxiliary material to the cartridge. For example, this outer layer may be in the form of an adhesive film and/or include one or more attachment features designed to releasably mate with the staple cartridge. In certain embodiments, the compression ratio of the lattice structure is greater than the compression ratio of at least one outer layer.

37A-37B show an exemplary embodiment of the support material 3700 disposed on the cartridge 3800. The cartridge 3800 is similar to the cartridge 200 of FIGS. 1-2C, and therefore common features will not be described in detail herein. The support material 3700 includes an internal lattice structure 3702 and two outer layers 3704, 3710, each having a different compression ratio relative to each other. The internal lattice structure 3702 is generally formed of interconnected repeating unit cells, which are omitted from this figure, but any of the repeating unit cells disclosed herein may be used, for example, a strut-less based repeating unit cell or a strut-based repeating unit cell. Further, the first outer layer 3704 is disposed on the top surface 3702a of the internal lattice structure 3702 and is configured to contact the tissue, and the second outer layer 3706 is disposed on the bottom surface 3702b of the internal lattice structure 3702 and is configured to contact the cartridge 3800.

While the first outer layer 3704 may have a variety of configurations, in the illustrated embodiment, the first outer layer 3704 is a lattice structure formed from interconnected struts 3710 that create hexagonal openings 3712 that extend through the first outer layer 3704. These openings 3712 may be configured to promote tissue ingrowth. Those skilled in the art will appreciate that the struts may be interconnected in a variety of other ways that result in openings of different sizes and shapes, and thus the lattice structure of the first outer layer is not limited to that shown in the figures. Additionally, the first outer layer 3704 may have a lower compression ratio, and therefore may be less compressible, at least as compared to the internal lattice structure 3702. As a result, this may allow tissue to further penetrate the openings 3712, and thus the auxiliary material 3700, when the auxiliary material 3700 is stapled to tissue, thereby further promoting tissue ingrowth (see FIGS. 38A and 38B).

While the second outer layer 3706 can have a variety of configurations, in this illustrated embodiment, the second outer layer 3706 is in the form of a film 3714 having protrusions 3716 extending outwardly therefrom. The protrusions 3716a, 3716b, 3716c are configured to mate with surface features 3802, 3804, 3806 of the cartridge 3800, such as surface features 216, 218, 220 of the cartridge 200 of FIGS. 1-2C. This mating interaction substantially prevents slidable movement of the support material 3700 relative to the cartridge 3800, as shown in FIGS. 37B and 38A. The shape and size of the protrusions 3716a, 3716b, 3716c, which may be triangular or diamond shaped, are complementary to the shape and size of the corresponding surface features 3802, 3804, 3806, which may be triangular or diamond shaped recessed channels. In other embodiments, the shapes and sizes of the protrusions and surface features may vary.

Alternatively or additionally, the second outer layer 3706 may include an elongated projection 3730 configured to be inserted into the longitudinal slot 3808 of the cartridge 3800. The elongated projection may have a variety of configurations, but in this illustrated embodiment, the elongated projection 3730 has a rectangular shape, and in some embodiments, the elongated projection 3730 may extend along the entire length of the support material (e.g., in the z-direction), while in other embodiments, the elongated projection 3730 may extend along only a portion of the length. In certain embodiments, the elongated projection 3730 may be broken down into smaller elongated separate portions.

In other embodiments, as shown in FIG. 39A, the second outer layer 3900 may include four sets of tabs 3902a, 3902b, 3904a, 3904b, 3906a, 3906b, 3908a, 3908b (3902b, 3904b, 3906b, and 3908b are partially obstructed in FIG. 39A), each extending outwardly and away from opposing outer surfaces 3900a, 3900b (FIG. 39B) of the second outer layer 3900. The four sets of tabs 3902, 3904, 3906, 3908 can have a variety of configurations, but in this illustrated embodiment, the four sets of tabs 3902, 3904, 3906, 3908 each have a hook shaped configuration that engages a respective portion of an opposing outer flange 3910a, 3910b, 3910a, 3910b, 3914a, 3914b, 3914a, 3914b of the cartridge 3901. Additionally, when the cartridge 3901 includes a longitudinal slot 3918, e.g., a knife slot, the second outer layer 3900 can include a pin feature 3912 configured to engage the longitudinal slot 3918. For example, the pin feature 3912 may include two opposing sets of pins (only one set of two opposing tabs 3912a, 3912b is shown in FIGS. 39A-39B) spaced apart from one another along the longitudinal slot 3918. As shown in more detail in FIG. 39B, the first pin 3912a engages with a first wall 3918a of the longitudinal slot 3918, and the second pin 3912b engages with a second opposing wall 3918b of the longitudinal slot 3918.

As noted above, in some embodiments, the second outer layer may be an adhesive film. In one exemplary embodiment, as shown in FIG. 40, the auxiliary material 4000 is disposed on the top surface 4001a of a cartridge 4001, such as the cartridge 200 of FIGS. 1-2C. The auxiliary material 4000 includes an internal structure 4002, a first outer layer 4004 disposed on the top surface 4002a of the internal structure 4002, and a second outer layer 4006 disposed on an opposing bottom surface 4000b opposite the top surface 4002a of the internal structure 4002. Other than the differences described in detail below, the auxiliary material 4000 may be similar to the auxiliary material 3700 of FIGS. 37A-38B, and thus the common features will not be described in detail herein. As shown, the internal structure 4002 is formed of interconnected repeating unit cells 4008, such as the unit cells 810 of FIGS. 8A-9B. Additionally, the second outer layer 4006 is in the form of an adhesive film attached to the top surface 4001a of the cartridge 4001. In this illustrated embodiment, the second layer 4006 is an adhesive film formed of a pressure sensitive adhesive. Additional details regarding adhesive films and other attachment methods may be found in U.S. Pat. No. 10,349,939, which is incorporated herein by reference in its entirety.

Staple Pocket Lattice In some embodiments, the support material may also include a lattice structure extending from the second outer layer and configured to be inserted into the staple pockets or recessed channels of the staple cartridge. For example, as shown in FIG. 41A, the support material 4100 includes an internal lattice structure 4102 extending between the two outer layers 4104, 4106. The internal lattice structure 4102 is generally formed of interconnected repeating unit cells, which are omitted from this figure, although any of the repeating unit cells disclosed herein may be used. Additionally, each of the two outer layers 4104, 4106 may be formed of either a lattice structure or a film, and thus the two outer layers are generally shown in each of FIGS. 41A-C. The first outer layer 4106 is configured to contact tissue, and the second outer layer 4104 is configured to generally contact the cartridge 4101, as shown in FIGS. 41B-C. Cartridge 4101 is similar to cartridge 200 of Figures 1-2C, and therefore common features will not be described in detail herein.

41A-41C, the auxiliary material 4100 includes staple pocket lattices 4110a, 4110b, 4110c extending outwardly from the second outer layer 4104. The staple pocket lattices may function as separate compression zones of the auxiliary material 4100, for example, the staple pocket lattices 4110a, 4110b, 4110c may have a different compression ratio than the bulk of the auxiliary material so as not to substantially add to the overall solid height of the auxiliary material. The staple pocket lattices may have various configurations, but in this illustrated embodiment, there are three longitudinal rows of two sets of staple pocket lattices 4110a, 4110b, 4110c on either side of the intended cutting line of the auxiliary material. The staple pocket lattices may have various configurations, but each staple pocket lattice is formed of five U-shaped struts. The shape and size of the perimeter surrounding each staple pocket lattice 4110a, 4110b, 4110c may be triangular or diamond shaped and may be complementary to the shape and size of the corresponding staple pocket 4112a, 4112b, 4112c, which may also be triangular or diamond shaped. In other embodiments, the lattice structure and the shape and size of the staple pockets may be different. As shown in Figures 41B-41C, when the auxiliary material 4100 is disposed on the cartridge 4101, at least a portion of the staples 4114a, 4114b, 4114c in the cartridge 4101 extend through the respective staple pocket lattices 4110a, 4110b, 4110c and are thus captured by the staple crowns when the auxiliary material is stapled to tissue. Thus, the staple pocket lattice may also aid in the attachment of the auxiliary material to the staple cartridge and/or the alignment of the auxiliary material relative to the staples.

The structural configurations of the unit cells disclosed herein can also be tailored to provide variable mechanical response within the same auxiliary material, e.g., in the lateral and/or longitudinal directions (e.g., y- and/or z-directions, respectively). For example, in certain embodiments, the auxiliary material can be formed with at least two or more different lattice structures positioned side-by-side to create at least two substantially different compressive properties within the same auxiliary material.

As generally shown in FIG. 42A, the auxiliary material 4200 may have one internal lattice structure 4202 and two external lattice structures 4204, 4206, each of which defines a respective compression zone C ₁ , C ₂ , C ₃ of the auxiliary material 4200. In this embodiment, the first and second external lattice structures are structurally identical, and therefore C ₂ and C ₃ are the same. As shown, the lattice structures 4202, 4204, 4206 are laterally offset from one another relative to the longitudinal axis of the auxiliary material 4200. That is, the first external lattice structure 4204 is positioned directly adjacent to a first longitudinal side (blocked) of the internal lattice structure 4202, and the second external lattice structure 4206 is positioned directly adjacent to a second opposing longitudinal side (blocked) of the internal lattice structure 4202. Each lattice structure may be formed with any of the repeating unit cells disclosed herein, and three lattice structures 4202, 4204, 4206 are shown without any unit cells. One skilled in the art will appreciate that each lattice structure may be formed with pillar-based repeating unit cells or pillar-less based repeating unit cells.

As further shown, the intended cut line C _L of the support material 4200 is defined across the internal lattice structure 4202 and along the longitudinal axis L _A of the support material 4200. Thus, in this illustrated embodiment, the internal lattice structure 4202 may be configured to be more rigid and therefore exhibit a higher resistance to compression as compared to the outer lattice structures 4204, 4206. Thus, the resulting support material 4200 may have a variable compressive strength in a direction transverse to the cut line C _L of the support material 24200 (e.g., in the y direction). This variable compressive strength may thus facilitate the transition of tissue compression at the outermost staple row 4210 as the support material is stapled to tissue, as shown in FIG. 42B.

43A-43B show another embodiment of a support material 4300 having variable compressive strength along a transverse direction (e.g., y-direction) relative to its longitudinal axis L _A. In this illustrated embodiment, the support material 4300 is formed of three different lattice structures 4310, 4320, 4330, each formed of different repeating units. More specifically, a first lattice structure 4310 is formed of interconnected first repeating unit cells 4310a, one of which is shown in FIG. 43A, a second lattice structure 4320 is formed of interconnected second repeating unit cells 4320a, one of which is shown in FIG. 43A, and a third lattice structure 4330 is formed of interconnected third repeating unit cells 4330a, one of which is shown in FIG. 43A. As described in more detail below, by designing each lattice structure differently, the resulting support material can have a variety of lateral compression responses.

The repeating unit cells 4310a, 4320a, 4330a can have a variety of configurations, but in this illustrated embodiment, the repeating unit cells 4310a, 4320a, 4330a are all pillar-based unit cells. Furthermore, depending on the location of the corresponding lattice structure, the repeating unit cells can be structurally configured to be more or less rigid compared to the repeating unit cells of other lattice structures, as described in more detail below.

Although the three lattice structures 4310, 4320, 4330 may be positioned relative to one another in a variety of different configurations, the first lattice structure 4310 is the central-most lattice structure of the auxiliary material 4300 through which the intended cutting line C _L of the auxiliary material 4300 extends along the longitudinal axis L _A. Thus, the first repeat unit cell 4310a may have a structural configuration that is less dense and therefore more flexible compared to the second and third repeat unit cells, as shown, for example, in FIG. 43A. Furthermore, the first lattice structure 4310 extends along the entire length L of the auxiliary material 4300. The second lattice structure 4320 is divided into two longitudinal portions 4325a, 4325b. A first longitudinal portion 4325a of the second lattice structure 4320 is positioned against a first longitudinal sidewall _L1 of the first lattice structure 4310, and a second longitudinal portion 4325b of the second lattice structure 4320 is positioned against a second opposing longitudinal sidewall _L2 of the first lattice structure 4310 (see FIG. 43B). Based on their position relative to the cut line C, the second repeat unit cell 4320a can be configured to be the densest and therefore the stiffest as compared to the first and third repeat unit cells 4310a, 4330a, as shown, for example, in FIG.

As further shown in FIG. 43A, the third lattice structure is divided into two U-shaped portions 4335a, 4335b, each of which is positioned against the outer walls of the first and second longitudinal portions 4325a, 4325b of the second lattice structure 4320 (only the outer longitudinal walls _L3 and _L4 of each portion 4325a, 4325b are shown in FIG. 43B). As a result, the third lattice structure 4320 defines at least a portion of the periphery of the support material 4300. Based on the position of the third lattice structure 4330, the third repeating unit cell may be configured to impart an intermediate density, and therefore an intermediate stiffness, compared to the first and second repeating cells 4310a, 4320a, as shown in FIG. 43A, which may help to facilitate the transition of tissue compression. Furthermore, the structural configuration of the third repeating unit 4330a may be configured to promote tissue ingrowth. In certain embodiments, a third lattice structure may also be disposed on at least a portion of the upper surface of the second lattice structure, which may further enhance tissue ingrowth into the support material.

In some embodiments, the dimensions (e.g., wall thickness and/or height) of the repeating unit cells may vary among other repeating unit cells. For example, FIGS. 44A-44C show another embodiment of a support material 4400 having variable compressive strength along a transverse direction (e.g., y-direction) relative to its longitudinal axis (e.g., z-direction) as a result of different dimensions of the repeating unit cells of the postless base. As shown in FIGS. 44A-44B, only half (e.g., the left half) of the support material 4400 is shown on a staple cartridge 4401 having three rows of staples 4405a, 4405b, 4405c. The three rows of staples 4405a, 4405b, 4405c can be generally uniform (e.g., nominally the same within manufacturing tolerances), however, in this illustrated embodiment, the staple height of the third row of staples 4405c (e.g., the outermost staple row) is greater than the staple height of the first and second rows of staples 4405a, 4405b. This difference in staple height can contribute to the overall compressive behavior of the support material. In this illustrated embodiment, the third row of staples 4405c applies a lower compressive force to the captured tissue and support material, e.g., within a staple entrapment area, than the compressive force applied by the first and second rows of staples 4405a, 4405b to the respective captured tissue and support material, e.g., within the respective staple entrapment areas. The support material 4400 includes two sets of three longitudinal arrays of repeating unit cells. Because both sets are identical, only the three arrays 4410, 4412, 4414 of one set and one repeating unit cell 4410a, 4412a, 4414a of each of the three arrays are shown in Figures 44A-44C.

The repeat unit cells 4410a, 4412a, 4414a may have a variety of configurations. In the illustrated embodiment, the repeat unit cells 4410a, 4412a, 4414a are similar in overall shape to the repeat unit cell 810 of FIGS. 9A-9B. However, the wall thickness and height between at least two repeat cells may vary. As shown, the wall thickness W _T of the innermost repeat unit cell 4410a (e.g., the first repeat unit cell) to the outermost repeat unit cell 4414a (e.g., the third repeat unit cell) decreases. That is, the wall thickness W _T1 of the innermost repeat unit cell 4410a is greater than the wall thickness W _T2 of the middle repeat cell 4412a, which is greater than the _{wall thickness W T3 of} the outermost repeat unit cell 4414. Additionally, the heights _H1 , _H2 of each of the innermost and intermediate repeat unit cells 4410a, 4412a are the same, and the heights _H1 , _H2 are greater than the height H3 of the outermost repeat unit cell 4414a. In other embodiments, only the wall thickness or heights vary between the arrays, the wall thicknesses vary between only two of the three arrays, or the heights vary among all three arrays.

Alternatively or additionally, in cases where the repeating unit cells are shaped similarly to a Schwartzian P structure, such as Schwartzian P structure 810 of Figures 8A-9B, the lengths of the hollow tubular interconnects between the repeating unit cells of different arrays may be different. For example, as further shown in Figure 44A, the hollow tubular interconnect 4416 between the innermost repeating unit cell 4410a and the middle repeating unit cell 4412a extends a first length _L1 , and the hollow tubular interconnect 4418 between the middle repeating unit cell 4412a and the outermost repeating unit cell 4414a extends a second length _L2 that is greater than the first length _L1 .

The compressive behavior of the repeating unit cells 4410, 4410a of the auxiliary material 4400 when the auxiliary material 4400 is stapled to tissue is shown diagrammatically in Figures 44B-44C. Thus, the different dimensions of the repeating unit cells in the lateral direction cause three different compression zones with different compressive strengths, the first zone being defined by a first longitudinal array 4410 of first repeating units 4410a having a first compressive strength (e.g., structural ability to withstand compressive forces in the x-direction), the second zone being defined by a second longitudinal array 4412 of second repeating unit cells 4412a having a second compressive strength, and the third zone being defined by a third longitudinal array 4414 of third repeating units 4414a having a third compressive strength. The compressive strength between each array may vary, but in this illustrated embodiment, the first compressive strength is greater than the second compressive strength, which is greater than the third compressive strength. Thus, the first repeat unit 4410a is stiffer than the second repeat antille unit 4412a, and the second repeat unit cell 4412a is stiffer than the third repeat unit cell 4414a.

Cartridge Surface Features In some embodiments, the staple cartridge can include surface features (e.g., staple pocket protrusions) that can be configured to interact with the auxiliary material to help retain the auxiliary material on the staple cartridge prior to staple deployment. For example, in certain embodiments, the surface features can include protrusions that extend outwardly from the top surface of the staple cartridge. Alternatively or additionally, the surface features can include recessed channels defined within the top surface of the staple cartridge. Thus, the auxiliary materials described herein, if present, can be designed with a variety of different configurations suitable for interacting with the surface features of the staple cartridge, thus providing a releasable attachment mechanism between the auxiliary material and the staple cartridge. Alternatively or additionally, the auxiliary materials described herein can be designed with a variety of configurations suitable for interacting with the staple legs that extend partially outwardly from their respective cavities within the staple cartridge.

45A-45C show an exemplary embodiment of a postless support material 4500 that may be configured to interact with surface features 4504 of the staple cartridge 4502. Alternatively or additionally, the support material 4500 may be configured to interact with legs of staples 4506, 4507, 4508 at least partially disposed within the staple cartridge 4502 (see FIGS. 45B-45C). The staple cartridge 4502 may have a variety of configurations, but in this illustrated embodiment, the staple cartridge 4502 is similar to the staple cartridge 200 of FIGS. 1-2C, except that the surface features 4504 are U-shaped projections extending outwardly from the top surface 4502a of the staple cartridge and positioned around respective end portions of the staple cavities defined within the cartridge 4502. As shown, the staple cavities are arranged in first and second sets of three longitudinal rows 4510a, 4510b, 4510c, 4512a, 4512b, 4512c, which are positioned over the longitudinal slots 4514 on the first and second sides, respectively. Furthermore, for each set, the first and third longitudinal rows 4510a, 4510c, 4512a, 4512c are parallel to one another, and the second longitudinal rows 4510b, 4512b are staggered relative thereto.

45A-45C, the support material 4500 is formed of interconnected repeating unit cells 4516, each unit cell being structurally similar to the repeating unit cell 810 of FIG. 9A-9B. Thus, the support material 4500 is similar to the support material 800 of FIG. 8A-8F, except that the repeating unit cells 4515 are rotated 45 degrees about the X-axis with respect to FIG. 8A. In other words, the support material 800 is shown in a 0-90 configuration, whereas the support material 4500 is shown in a ±45 degree orientation. As a result, the repeating unit cells 4516 are oriented (e.g., in a repeating pattern) to coincide with the positions of the surface features 4504 and/or staple cavities 4510a, 4510b, 4510c, 4512a, 4512b, 4512c.

As shown in FIG. 45A, the repeating unit cells 4516 are interconnected with one another and arranged in seven longitudinal rows 4516a, 4516b, 4516c, 4516d, 4516e, 4516f, 4516g, each row defining voids between adjacent unit cells (voids 4518a, 4518b, 4518c, 4520a, 4520b, 4520c are shown in FIG. 45 and voids 4518a, 4518b, 4518c, 4522a, 4522b, 4524a, 4524b, 4524c are shown in FIGS. 45B-C). The first three longitudinal rows 4516a, 4516b, 4516c are configured to overlap with the respective staple cavity rows 4510a, 4510b, 4510c, the central most row 4516d is configured to overlap with the longitudinal slot 4514, and the last three longitudinal rows 4516e, 4516f, 4516g are configured to overlap with the respective staple cavity rows 4512a, 4512b, 4512c. As a result, as partially shown in FIGS. 45B-45C, based on the location of the surface features 4504 relative to the staple cavities, each surface feature 4504 overlaps with and at least partially extends through a corresponding void. Thus, each void is configured to receive and engage at least one surface feature, thereby retaining the support material 4500 in the cartridge 4502 prior to staple deployment. In other embodiments, all or some of the voids can be replaced with thin regions of material that can at least be penetrated by the surface features.

45B-45C, for each staple cavity row and corresponding row of repeating unit cells, each staple disposed within the staple cavity (only staples 4506, 4507, 4508 and corresponding staple cavity rows 4510a, 4510b, 4510c are shown in FIG. 45B) extends across the respective repeating unit cell such that each staple leg overlaps a corresponding void positioned on one side of the repeating unit cell. For example, as shown in FIG. 45B, for repeating unit cell 4515a and corresponding staple 4508 in first unit cell row 4516a, first leg 4508a and second leg 4508b of staple 4508 overlap first void 4518a and second void 4518b, respectively, on either side of repeating unit cell 4515b in second unit cell row 4516b. As further shown in FIG. 45C, the staple legs 4507a, 4507b extend at least partially through the gaps 4522a, 4522b, respectively, when the support material 4500 is positioned on the top surface 4502a of the staple cartridge 4502. This can further retain the support material 4500 in the cartridge 4502 prior to staple deployment. Thus, the repeating unit cells of the support material can be configured to be positioned between and engage the first and second staple legs of the corresponding staples.

46A-46B show another exemplary embodiment of a post-based support 4600 that can be configured to interact with surface features of a staple cartridge 4602. The staple cartridge 4602 is similar to the staple cartridge 3901 of FIG. 39A, and therefore common features will not be described in detail herein. Each surface feature has a U-shaped configuration and is positioned around a respective end of a respective staple cavity, and thus extends along a respective longitudinal row of staple cavities (only three longitudinal rows of staple cavities 4603a, 4603b, 4603c, and therefore only three longitudinal rows of surface features are shown in FIGS. 46A-46B).

As shown in more detail in FIG. 46B, the first surface features of the longitudinal row (only four first surface features 4604a, 4604b, 4604c, 4604d are shown) and the third surface features of the longitudinal row (only four third surface features 4608a, 4608b, 4608c, 4608d are shown) are aligned laterally with one another in the y direction, thus forming a set of first transverse rows 4605a, 4605b, 4605c, 4605d, each having a first and third surface feature. The second surface features of the longitudinal rows (only four second surface features 4606a, 4606b, 4606c, 4606d are shown) are laterally offset in the z-direction relative to the first and second surface features, thus forming a set of second transverse rows 4607a, 4607b, 4607c, 4607d, each having a respective second surface feature.

Furthermore, except for the differences described in detail below, the auxiliary material 4600 is similar to the auxiliary material 3000 of Figures 30A-30B. The auxiliary material 4600 includes a tissue contact layer 4616, a cartridge contact layer 4618, and an internal structure 4620 extending therebetween.

As shown in FIG. 46 and in more detail in FIG. 46B, each opening (only eight openings 4622a, 4622b, 4622c, 4622d, 4622e, 4622f, 4622g, 4622h are shown) in the cartridge contact layer 4618 is configured to receive at least one respective surface feature such that when the support material 4600 is positioned over the staple cartridge 4602, each respective surface feature extends into the cartridge contact layer 4618 and engages a respective opening. For example, as shown in FIG. 46, the first and third surface features 4604a, 4608a of the first lateral row 4605a extend into the first opening 4622a and engage at least the first cross strut 4624a, while the second surface feature 4606a of the second lateral row 4607a extends into the second opening 4622b and engages at least the first cross strut 4624a and the opposing cross strut 4624b.

The cross struts of the cartridge contact layer 4618 (only eight cross struts 4624a, 4624b, 4624c, 4624d, 4624e, 4624f, 4624g are shown in FIG. 46B) can have a variety of configurations. For example, in some embodiments, the width of the cross struts (e.g., in the z-direction) can be substantially uniform (e.g., uniform within manufacturing tolerances), while in other embodiments, the width of the cross struts can be non-uniform. In this illustrated embodiment, the widths of the cross struts 4624a, 4624c, 4624e, 4624g are uniform, while the widths of the remaining cross struts 4624b, 4624d, 4624f are non-uniform. One skilled in the art will appreciate that the structural configuration of the cross struts of the cartridge contact layer can depend at least on the structural configuration of the surface features. For example, in this illustrated embodiment, at least a portion of the cross struts include boeing segments to accommodate the U-shaped configuration of the surface features. Depending on the orientation of the U-shaped configuration, some of the bowing segments have a convex configuration, while other bowing segments have a concave configuration. Additionally, the structural configurations of the cross struts 4626a, 4626b, 4626c, 4626d, 4626e, 4626f, 4626g of the tissue contacting layer 4616 may have various configurations, but as shown in FIG. 46A, the cross struts 4626a, 4626b, 4626c, 4626d, 4626e, 4626f, 4626g are structurally similar to the corresponding cross struts 4624a, 4624b, 4624c, 4624d, 4624e, 4624f, 4624g of the cartridge contacting layer 4618.

Variable Tissue Gaps In some embodiments, it may be desirable to have a variable tissue gap between the support material and the anvil to enhance gripping and stabilization of the tissue while stapling and/or cutting the tissue. However, a variable tissue gap may adversely affect the ability of the support material to apply a generally uniform pressure to the stapled tissue. Thus, as described in more detail below, the support material disclosed herein may be configured to create a variable tissue gap for tissue manipulation and may be further configured to apply a generally uniform pressure (e.g., a pressure in the range of about 30 kPa to 90 kPa) to the tissue stapled to the support material for a predetermined period of time (e.g., at least three days) when the tissue is stapled. In certain embodiments, the support material may apply a pressure of at least about 30 kPa for at least three days. In such embodiments, after three days, the support material may be configured to apply an effective amount of pressure (e.g., about 30 kPa or less) to the tissue such that the tissue may remain sealed throughout the healing cycle of the tissue (e.g., about 28 days). For example, the support material can be configured to apply pressure to the stapled tissue that decreases (eg, a linear decrease) from about 30 kPa to 0 kPa over a predetermined period of time from about 3 days to about 28 days.

In general, the support material may include a tissue contact surface, a cartridge contact surface, and an interior structure extending therebetween, the interior structure including at least two lattice structures each having a different compressive strength. The at least two lattice structures may differ in structure, shape, or interconnections laterally along the width of the lattice structure and/or longitudinally along the length of the lattice structure to form a variable tissue gap. In some embodiments, the base geometry of the support material may be formed of strut-less based unit cells. In such embodiments, the outer geometry of the support material may be formed of a strut-based lattice structure. In other embodiments, the base geometry may be formed of strut-based unit cells.

47A-47B show an exemplary embodiment of a surgical end effector 4700 having an anvil 4702 and a staple fastening assembly 4704. The staple fastening assembly 4704 includes a support 4706 that is releasably held on a top or deck surface 4707a (e.g., the cartridge surface facing the anvil) of a staple cartridge 4707. The staple cartridge 4707 is similar to the cartridge 200 of FIGS. 1-2C, and therefore common features will not be described in detail herein. Although not shown, the anvil 4702 is pivotally coupled to an elongated staple channel, such as the elongated staple channel 104 of FIG. 1, and the staple fastening assembly 4704 is positioned within and coupled to the elongated staple channel. The anvil 4702 may have a variety of configurations, but as shown in FIGS. 47A-47B , the anvil includes a cartridge-facing surface having staple pockets 4708 defined therein with a generally planar (e.g., planar within manufacturing tolerances) tissue compression surface 4710 extending between the staple pockets 4708 (e.g., extending in the y-direction). FIG. 47A shows the surgical end effector 4700, and thus the anvil 4702, in a fully closed position, while FIG. 47B shows tissue T clamped between the anvil 4702 and the staple fastening assembly 4704 and stapled to the support material 4706 via staples (only two sets of three 4712a, 4712b, 4712c, 4714a, 4714b, 4714c are shown). Prior to deployment, in some embodiments, the staples may be fully disposed within the staple cartridge 4707, as shown in FIGS. 47A and 47C, while in other embodiments, some or all of the staples may be partially disposed within the staple cartridge 4707. The staples 4712a, 4712b, 4712c, 4714a, 4714b, 4714c may have a variety of configurations, but in this illustrated embodiment, the staples 4712a, 4712b, 4712c, 4714a, 4714b, 4714c have a pre-deployed (e.g., unformed) staple height that is at least substantially uniform (e.g., nominally the same within manufacturing tolerances). In some embodiments, the staples 4712a, 4712b, 4712c, 4714a, 4714b, 4714c may be substantially uniform (e.g., nominally the same within manufacturing tolerances).

As shown in FIG. 47A and in more detail in FIG. 47C, the support material 4706 has a tissue contacting surface 4716, a cartridge contacting surface 4718, and an internal structure 4720 extending therebetween. The internal structure 4720 can have a variety of configurations, but in this illustrated embodiment, the internal structure includes two lattice structures 4722, 4724, each having a different compressive strength, such that the support material 4706 is configured to apply a generally uniform pressure to the stapled tissue for a predetermined period of time when in a tissue deployment state. In this illustrated embodiment, the first lattice structure 4722 is configured to have a first compressive strength and the second lattice structure 4724 is configured to have a second compressive strength that is greater than the first compressive strength.

Each of the first and second lattice structures 4722, 4724 may generally be formed of unit cells, such as those disclosed herein, e.g., pillar-free and/or pillar-based unit cells. For example, in certain embodiments, one or more unit cells may include at least one triply periodic minimal surface structure, such as those disclosed herein. Alternatively or additionally, one or more unit cells may be defined by interconnected pillars (e.g., planar pillars), such as pillar-based unit cells disclosed herein. In certain embodiments, the first and second lattice structures 4722, 4724 may differ in density (e.g., number of unit cells) and/or shape. Thus, the specific structural configuration of each of the first and second lattice structures 4722, 4724 is not shown, except for the general shape and thickness.

The first and second lattice structures 4722, 4724 each extend from an upper surface 4722a, 4724a to a bottom surface 4722b, 4724b. Depending on the overall structural configuration of the support material, at least a portion of the upper surface of at least one lattice structure may function as a tissue contact surface of the support material, and at least a portion of the bottom surface of at least one lattice structure may function as a cartridge contact surface of the support material. In this illustrated embodiment, the first lattice structure 4722 is positioned on top of the second lattice structure 4724 such that the bottom surface 4722b of the first lattice structure 4722 and the upper surface 4724a of the second lattice structure 4724 are in contact. Thus, the upper surface 4722a of the first lattice structure 4722 thus forms the tissue contact surface 4716, and the bottom surface 4724b of the second lattice structure 4724 thus forms the cartridge contact surface 4718. As a result, the shape of the upper surface 4722a of the first lattice structure 4722 can create a tissue gap between the anvil 4702 and the staple fastening assembly 4704 that is independent of the shape of the upper surface or deck surface 4707a of the staple cartridge 4707.

The top and bottom surfaces 4722a, 4724a, 4724a, 4724b of each lattice structure 4722, 4724 can have a variety of different shapes. In this illustrated embodiment, the top and bottom surfaces 4722a, 4722b of the first lattice structure 4722 each have a convex configuration. Thus, the top surface 4724a of the second lattice structure 4724 has a concave configuration. Additionally, because the top or deck surface 4707a of the staple cartridge 4707 has a generally planar configuration (e.g., in the YZ plane), the bottom surface 4724b of the second lattice structure 4724 also has a generally planar configuration (e.g., in the YZ plane). Thus, the overall geometric shape of the resulting auxiliary material 4706 creates a curved tissue contact surface 4716 against the tissue compression surface 4710 of the anvil 4702, thus creating a variable tissue gap (e.g., two different gap amounts shown as T _G1 , T _G2 ) between the anvil 4702 and the stapling assembly 4704.

In this illustrated embodiment, due to the concave shape of the upper surface 4722a of the first lattice structure 4722, the total thickness T _C (e.g., in the x direction) at the center of the support material 4706 (e.g., as indicated by the dotted line 4726 equidistant from the two opposing terminal lateral edges 4728a, 4728b) is greater than the total thicknesses _P1 , T _P2 (e.g., in the x direction) at each of the terminal lateral edges 4728a, 4728b of the support material 4706 (e.g., the outer longitudinal perimeter of the support material 4706 extending in the z direction). As a result, the overall uncompressed thickness of the support material 4706 varies laterally outward (e.g., in the ±y direction) along its width relative to its center, and therefore varies laterally relative to the longitudinal axis (e.g., extending in the z direction) of the support material 4706. Thus, the uncompressed thickness of the support material decreases laterally while the tissue gap increases. Additionally, the two distal lateral edges 4728a, 4728b are shown to be the same thickness, such that the lateral change in thickness from the center of the support material 4706 to each edge is the same. In other embodiments, the two distal lateral edges can have different thicknesses, such that the lateral change in thickness from the center of the support material to each edge is different.

As further shown, due to the concave-convex surface relationship between the first and second lattice structures 4722, 4724, as well as their position and compressive strength relative to one another, the thickness (e.g., x-direction) of each lattice structure also varies laterally outward (e.g., ±y-direction) along their respective lengths (e.g., z-direction) relative to their respective centers, which in this embodiment are also the center of the support material 4706 (indicated by dotted line 4726). Thus, in this illustrated embodiment, the first lattice structure 4722 is thicker than the second lattice structure 4724 at the center of the support material, and the second lattice structure 4724 is thicker than the first lattice structure 4722 at each of the distal lateral edges 4728a, 4728b of the support material 4706. As a result, the auxiliary material 4706 is most compressible at its center and least compressible at its distal lateral edges 4728a, 4728b, and thus when in a tissue deployment state, the auxiliary material 4706 can be compressed to a substantially uniform thickness T _compression (see FIG. 47B). This allows the auxiliary material 4706 to apply pressure that is not proportional to its uncompressed variable thickness. Thus, when the auxiliary material is stapled to a substantially uniform tissue T (e.g., tissue having the same or substantially the same thickness across the width of the auxiliary material, in the y direction) with staples 4712a, 4712b, 4712c, 4714a, 4714b, 4714c, the auxiliary material 4706 can apply a substantially uniform pressure P to the stapled tissue T (see FIG. 47B).

48A-48B show another exemplary embodiment of a surgical end effector 4800 having an anvil 4802 and a staple fastening assembly 4804. The staple fastening assembly 4804 includes a support 4806 that is releasably held on a top or deck surface 4807a (e.g., the cartridge surface facing the anvil) of a staple cartridge 4807. Except for the differences described below, the anvil 4802 is similar to the anvil 4702 of FIGS. 47A-47B and the staple cartridge 4807 is similar to the cartridge 200 of FIGS. 1-2C except that the top or deck surface 4807a is curved, and therefore the common features will not be described in detail herein. FIGURE 48A shows the surgical end effector 4800, and thus the anvil 4802, in a fully closed position, while FIGURE 48B shows tissue T clamped between the anvil 4802 and the stapling assembly 4802 and stapled to the support material 4806 via staples (only two sets of three 4812a, 4812b, 4812c, 4814a, 4814b, 4814c are shown). Prior to deployment, in some embodiments, the staples may be fully disposed within the staple cartridge 4807, as shown in FIGUREs 48A and 48C, while in other embodiments, some or all of the staples may be partially disposed within the staple cartridge 4807. The two sets of staples 4812a, 4812b, 4812c, 4814a, 4814b, 4814c can have various configurations, but in this illustrated embodiment, the staples in the two sets are the same, such that for each set, the first staples 4812a, 4814a (e.g., the innermost row of staples) have a first height, the second staples 4812b, 4814b (e.g., the middle row of staples) have a second height that is greater than the first height, and the third staples 4812c, 4814c (e.g., the outermost row of staples) have a third height that is greater than the second height.

As shown in FIG. 48A and in more detail in FIG. 48C, the support material 4806 has a tissue contact surface 4816, a cartridge contact surface 4818, and an internal structure 4820 extending therebetween. While the internal structure 4820 can have a variety of configurations, in this illustrated embodiment, the internal structure 4820 includes two lattice structures 4822, 4824, each having a different compressive strength, such that the support material 4806 is configured to apply a generally uniform pressure to the stapled tissue for a predetermined period of time when in a tissue deployment state. In this illustrated embodiment, the first lattice structure 4822 is configured to have a first compressive strength and the second lattice structure 4824 is configured to have a second compressive strength that is greater than the first compressive strength.

Each of the first and second lattice structures 4822, 4824 may generally be formed of unit cells, such as those disclosed herein, e.g., pillar-free and/or pillar-based unit cells. For example, in certain embodiments, one or more unit cells may include at least one triply periodic minimal surface structure, such as those disclosed herein. Alternatively or additionally, one or more unit cells may be defined by interconnected pillars (e.g., planar pillars), such as the pillar-based unit cells disclosed herein. Thus, the specific structural configuration of each of the first and second lattice structures 4822, 4824 is not shown, except for the general shape and thickness.

The first and second lattice structures 4822, 4824 each extend from an upper surface 4822a, 4824a to a bottom surface 4822b, 4824b. Depending on the overall structural configuration of the support material, at least a portion of the upper surface of at least one lattice structure may function as a tissue contact surface of the support material, and at least a portion of the bottom surface of at least one lattice structure may function as a cartridge contact surface of the support material. In this illustrated embodiment, the first lattice structure 4822 is narrower in width (e.g., in the y direction) compared to the second lattice structure, and is therefore positioned only on top of the central region 4823 of the second lattice structure 4824. Thus, the entire bottom surface 4822b of the first lattice structure 4822 contacts only a portion of the upper surface 4824a of the second lattice structure 4824, e.g., the upper surface 4823a of only the central region 4823. As a result, the top surface 4822a of the first lattice structure 4822 and the two exposed portions 4825a, 4825b of the top surface 4824a of the second lattice structure 4824 form the tissue contact surface 4816, and the bottom surface 4824b of the second lattice structure 4824 forms the cartridge contact surface 4818.

The top and bottom surfaces 4822a, 4824a, 4824a, 4824b of each lattice structure 4822, 4824 may have a variety of different shapes. Those skilled in the art will appreciate that the shape of the top and bottom surfaces may depend at least on the top or deck surface of the staple cartridge on which the support material is releasably held. In this illustrated embodiment, the top and bottom surfaces 4822a, 4822b of the first lattice structure 4822 each have a convex configuration. Thus, the top surface 4823a of the central region 4823 of the second lattice structure 4824 has a convex configuration, while the two exposed portions 4825a, 4825b of the top surface 4824a of the second lattice structure 4824 each have a generally planar configuration (e.g., extending in the y direction). Furthermore, since the top surface or deck surface 4807a of the staple cartridge 4807 has a convex configuration, the bottom surface 4824b of the second lattice structure 4824 has a concave configuration.

In this illustrated embodiment, due to the structural connection relationship of the first and second lattice structures 4822, 4824 and the resulting tissue contact surface 4816, the total thickness T _C (e.g., in the x direction) at the center of the support material 4806 (e.g., as indicated by the dotted line 4826 equidistant from the outermost terminal lateral edges 4828a, 4828b) is less than the total thicknesses T P1 , T P2 (e.g., in the x direction) at each of the outermost terminal lateral edges _4828a , _4828b of the support material (e.g., the outer longitudinal perimeter of the support material 4806 extending in the z direction). As a result, the overall uncompressed thickness of the support material 4806 varies laterally outward (e.g., in the ±y direction) along its width relative to its center. Thus, the overall uncompressed thickness of the support material varies laterally relative to the longitudinal axis (e.g., extending in the z direction) of the support material 4806.

As further shown, due to at least the structural relationship of the first and second lattice structures 4822, 4824 and their compressive strength relative to one another in combination with the curved configuration of the top surface 4807a of the staple cartridge 4807, the thickness of each lattice (e.g., in the x-direction) also varies laterally outward (e.g., in the ±y-direction) along their respective lengths relative to their respective centers of the support material 4806 in this embodiment (indicated by the dotted lines 4826). Thus, in this illustrated embodiment, the first lattice structure 4822 is thicker than the second lattice structure 4824 at the center of the support material 4806. As a result, the support material 4806 is most compressible at its center and least compressible at its outermost terminal lateral edges 4828a, 4828b. This allows the support material 4806 to apply a generally uniform pressure despite the variation in its compressed thickness. Thus, when the support material is stapled to a substantially uniform tissue T (e.g., tissue T having the same or substantially the same thickness (e.g., in the x direction) across the width (e.g., in the y direction) of the support material using staples 4812a, 4812b, 4812c, 4814a, 4814b, 4814c), the support material 4806 is compressed to a non-uniform compressed thickness while applying a generally uniform pressure P to the stapled tissue T (see FIG. 48B). As further shown, in this illustrated embodiment, only the second lattice 4824 overlaps the outermost rows of staples 4812c, 4814c.

In other embodiments, the second lattice structure may be narrower than the first lattice structure. For example, as shown in FIG. 49, the support material 4900 includes first and second lattice structures 4906, 4908 having a semicircular concentric configuration, with the first lattice structure 4906 surrounding the second lattice structure 4908. As a result, the top surface 4906a of the first lattice structure 4906 forms the tissue contact surface 4902 of the support material 4900, and the bottom surfaces 4906b, 4908b of the first and second lattice structures 4906, 4908 form the cartridge contact surface 4904 of the support material 4900.

As noted above, the support material may have two lattice structures that differ in structure, shape, or interconnections longitudinally (e.g., in the z-direction) along the length of the support material. For example, as shown in Figures 50A-50B, the support material 5002 includes two lattice structures 5004, 5006, each of which differs in structure and shape relative to one another and along the length of the support material (e.g., extending along the longitudinal axis L _A , in the z-direction).

Figures 50A-50B illustrate an exemplary embodiment of a surgical end effector 5000 that is similar to surgical end effector 5000, except that the support material 5002 has a variable compressive strength along its length extending along longitudinal axis L _A (e.g., in the z-direction). As shown in Figure 50A and shown in more detail in Figure 50C, the support material 5002 is positioned on an upper surface or deck surface 5003a of a staple cartridge 5003. The staple cartridge 5003 is similar to staple cartridge 4707 of Figures 47A-47C with staples 4712a, 4712b, 4712c, 4714a, 4714b, 4714c disposed therein, and therefore common features will not be described herein.

The support material 5002 has a tissue contact surface 5008, a cartridge contact surface 5010, and an internal structure 5012 extending therebetween. The internal structure 5012 may have a variety of configurations, but the first and second lattice structures 5004, 5006 each have a different compressive strength such that the support material 5002 is configured to apply a substantially uniform pressure (e.g., a pressure in the range of 30 kPa to 90 kPa) to the tissue stapled to the support material for a predetermined period of time (e.g., at least 3 days) when in a tissue deployment state. In this illustrated embodiment, the first lattice structure 5004 is configured to have a first compressive strength, and the second lattice structure 5006 is configured to have a second compressive strength that is greater than the first compressive strength. Thus, the second lattice structure 5004 is more rigid compared to the first lattice structure 5006. In other embodiments, the first lattice structure may be more rigid than the second lattice structure.

Each of the first and second lattice structures 5004, 5006 may generally be formed of unit cells, such as those disclosed herein, e.g., pillar-free based unit cells and/or pillar-based unit cells. For example, in certain embodiments, one or more unit cells may include at least one triply periodic minimal surface structure, such as those disclosed herein. Alternatively or additionally, one or more unit cells may be defined by interconnected pillars (e.g., planar pillars), such as pillar-based unit cells disclosed herein. In certain embodiments, the first and second lattice structures 5004, 5006 may differ in density (e.g., number of unit cells) and/or shape. Thus, the specific structural configuration of each of the first and second lattice structures 5004, 5006 is not shown, except for the general shape and thickness.

The first and second lattice structures 5004, 5006 each extend from an upper surface 5004a, 5006a to a bottom surface 5004b, 5006b. Depending on the overall structural configuration of the support material, at least a portion of the upper surface of at least one lattice structure may function as a tissue contact surface of the support material, and at least a portion of the bottom surface of at least one lattice structure may function as a cartridge contact surface of the support material. In this illustrated embodiment, the first lattice structure 5004 is positioned on top of the second lattice structure 5006 such that the bottom surface 5004b of the first lattice structure 5004 and the upper surface 5006a of the second lattice structure 5006 are in contact. Thus, the upper surface 5004a of the first lattice structure 5004 forms the tissue contact surface 5008, and the bottom surface 5006b of the second lattice structure 5006 therefore forms the cartridge contact surface 5010.

The first and second lattice structures 5004, 5006 can have various configurations, with each lattice structure having a different uncompressed thickness (e.g., in the x-direction) along the length of the support material (e.g., extending in the z-direction). As shown, the top surface 5004a of the first lattice structure 5004 is sloped from the proximal end 5002a to the distal end 5002b of the support material 5002. Furthermore, because the top surface or deck surface 5003a of the staple cartridge 5003 has a generally planar configuration (e.g., in the XZ plane), the bottom surface 5006b of the second lattice structure 5006 also has a generally planar configuration (e.g., in the XZ plane). As a result, a variable tissue gap (e.g., two different gap amounts are shown in T _G1 , T _G2 ) is created between the anvil 5001 and the support material 5002 that is independent of the shape of the top surface or deck surface 5003a of the staple cartridge 5003.

When the support material is stapled to tissue, the uncompressed thickness of each lattice structure along the length of the support material, in combination with the first and second compressive strengths and the variable tissue gap, as shown in FIG. 50B, can allow the support material to apply a substantially uniform pressure P to the stapled T (see FIG. 50B).

Consistent Tissue Gap In some embodiments, it may be desirable to have a consistent tissue gap between the support material and the anvil to enhance gripping and stabilization of the tissue while stapling and/or cutting the tissue. However, a consistent tissue gap may adversely affect the ability of the support material to apply a substantially uniform pressure to the stapled tissue. Thus, as described in more detail below, the support material disclosed herein may be configured to create a consistent tissue gap for tissue manipulation and may be further configured to apply a substantially uniform pressure (e.g., a pressure in the range of about 30 kPa to 90 kPa) to the stapled tissue to the support material for a predetermined period of time (e.g., at least three days) when stapled to the tissue. In certain embodiments, the support material may apply a pressure of about 30 kPa for at least three days. In such embodiments, after three days, the support material may be configured to apply an effective amount of pressure (e.g., a linear decrease in pressure, e.g., about 30 kPa or less) to the tissue such that the tissue may remain sealed throughout the healing cycle of the tissue (e.g., about 28 days). For example, the support material can be configured to apply pressure to the stapled tissue that decreases (eg, a linear decrease) from about 30 kPa to 0 kPa over a predetermined period of time from about 3 days to about 28 days.

In some embodiments, the support may be designed with a tissue contacting surface that is at least a portion of substantially planar (e.g., in the y-direction) and an opposing cartridge contacting surface that is non-planar (e.g., along the width of the support, e.g., in the y-direction). The non-planar surface of the cartridge contacting surface may vary, for example, along and in proportion to a curved or stepped top or deck surface of the staple cartridge (e.g., the cartridge surface facing the anvil) or a stepped tissue compression surface of the anvil.

In general, the auxiliary material may include a tissue contact surface, a cartridge contact surface, and an internal structure extending therebetween. In some embodiments, the auxiliary material may be formed of at least two lattice structures, a first lattice structure having a non-planar bottom surface that defines at least a portion of the cartridge contact surface, and a second lattice structure (e.g., a primary lattice structure) having a top surface that is generally planar and has at least a portion that defines at least a portion of the tissue contact surface. In other embodiments, the internal structure may be formed of a single lattice structure formed of repeating unit cells that differ in shape and/or size transversely to the longitudinal axis of the auxiliary material. As a result, the auxiliary material may have an overall geometry that creates a tissue contact surface having planar and non-planar surfaces, and a non-planar cartridge contact surface configured to mate with a non-planar tao (e.g., a cartridge surface facing the anvil) that is configured to mate with a curved or stepped top or deck surface of the staple cartridge. Thus, a generally consistent tissue gap may be created independent of the shape of the top or deck surface of the staple cartridge.

In some embodiments, the dimensions (e.g., wall thickness and/or height) of the repeating unit cells can be varied so that when the support material is stapled to tissue, the support material can apply a substantially uniform pressure (e.g., pressure in the range of 30 kPa to 90 kPa) to the stapled tissue for a predetermined period of time (e.g., at least three days). For example, the repeating unit cells of one longitudinal row can be different compared to the repeating unit cells of an adjacent longitudinal row. Thus, the support material can be designed such that the support material can create a consistent tissue gap with the anvil prior to staple deployment and can apply a substantially uniform pressure (e.g., pressure in the range of 30 kPa to 90 kPa) to the stapled tissue for a predetermined period of time (e.g., at least three days) when in a tissue deployment state.

51A illustrates an exemplary embodiment of a surgical end effector 5100 having an anvil 5102 and a staple fastening assembly 5104. The staple fastening assembly 5104 includes a support 5106 that is releasably held on a top or deck surface 5108a (e.g., the cartridge surface facing the anvil) of a staple cartridge 5108. Other than the differences described in detail below, the staple cartridge 5108 is similar to the cartridge 4807 of FIGS. 48A-48C, and thus the common elements will not be described in detail herein. Although not shown, the anvil 5102 is pivotally coupled to an elongated staple channel, such as the elongated staple channel 104 of FIG. 1, and the staple fastening assembly 5104 is positioned within and coupled to the elongated staple channel. 51A , the anvil 5102 includes a cartridge-facing surface having staple pockets 5110 defined therein, with a generally planar tissue compression surface 5112 extending between the staple pockets 5110. FIG. 51A shows the surgical end effector 5100, and thus the anvil 5102, and the staples disposed within the staple cartridge 5108 (only two sets of three staples 5114a, 5114b, 5114c, 5116a, 5116b, 5116c are shown), in a fully closed position with no tissue positioned between the anvil 5102 and the support material 5106. Prior to deployment, in some embodiments, staples 5114a, 5114b, 5114c, 5116a, 5116b, 5116c can be partially disposed within staple cartridge 5108, as shown in FIG. 51A, while in other embodiments, some or all of the staples can be completely disposed within staple cartridge 5108. While staples 5114a, 5114a, 5114c, 5116a, 5116b, 5116c can have a variety of configurations, in this illustrated embodiment, staples 5114a, 5114a, 5114c, 5116a, 5116b, 5116c have a pre-deployed (e.g., unformed) staple height that is at least approximately uniform (e.g., nominally the same within manufacturing tolerances). In some embodiments, the staples 5114a, 5114a, 5114c, 5116a, 5116b, 5116c can be substantially uniform (e.g., nominally identical within manufacturing tolerances).

As shown in FIG. 51A and in more detail in FIG. 51B, the support material 5106 has a tissue contacting surface 5118, a cartridge contacting surface 5120, and an internal structure 5122 extending therebetween. While the internal structure 5122 can have a variety of configurations, in the illustrated embodiment, the internal structure 5122 includes two different lattice structures 5124, 5126. The first and second lattice structures 5124, 5126 extend from top surfaces 5124a, 5126a to bottom surfaces 5124b, 5126b, respectively.

The first lattice structure 5124 may generally be formed of posts such as posts 5228a, 5228b, 5228c, 5228d, 5230a, 5230b, 5230c, 5230d in FIGS. 52A-B, or unit cells such as those disclosed herein, e.g., post-free based unit cells and/or post-based unit cells. Thus, the specific structural configuration of the first lattice structure 5124 is not shown, except for the general overall shape and thickness.

The first lattice structure 5124 extends between the second lattice 5126 structure and the top or deck surface 5108a of the staple cartridge 5108. As shown, the uncompressed thickness of the first lattice structure 5124 varies laterally relative to the longitudinal axis _LA of the support material 5106 (e.g., _LA extends in the z-direction). These lateral differences can be proportioned along the curved top or deck surface 5108a of the staple cartridge 5108 such that the portion of the cartridge contact surface 5120 of the support material 5106 formed by the bottom surface 5124b of the first lattice structure 5124 is complementary to the curved top or deck surface 5108a of the staple cartridge 5108 (e.g., a concave configuration). As a result, the variations in thickness of the first lattice structure 5124 can accommodate the variations in the top or deck surface 5108a. This further results in a lateral change in the compression ratio of the first lattice structure 5124, which in this illustrated embodiment increases due to the lateral increase in uncompressed thickness such that the compressive behavior of the auxiliary material 5106 is primarily driven by the compressive properties of the second lattice structure 5126.

The second lattice structure 5126 is formed of interconnected repeating unit cells arranged in three longitudinal arrays in two sets, the first set positioned on one side of the intended cutting line of the auxiliary material and the second set positioned on the second side of the intended cutting line of the auxiliary material. For simplicity, only three unit cells 5132a, 5132b, 5132c, 5134a, 5134b, 5134c from each set are shown. The repeating unit cells may have a variety of configurations, but in this illustrated embodiment, all of the repeating unit cells have generally uniform dimensions (e.g., nominally identical within manufacturing tolerances) and are similar to the repeating unit cells 810 of Figures 9A-9B, and therefore the common features will not be described in detail herein. The second lattice structure is therefore similar to the auxiliary material 800 of Figures 8A-8F, and therefore the common features will not be described herein.

As shown, at least a portion of the upper surface 5126a is generally planar and thus includes a generally planar surface 5127 (e.g., in each of the y directions) with a non-planar surface 5129 extending therebetween. The upper surface 5126a defines the tissue contacting surface 5118 of the auxiliary material 5106, such that the tissue contacting surface 5118 is formed of the planar surface 5127 and the non-planar surface 5129. The generally planar surfaces 5127 and non-planar surfaces 5129 of the upper surface, and thus the tissue contacting surface 5118, alternate along the width of the second lattice structure 5126 (extending in the y direction) such that a consistent tissue gap (e.g., alternating between a generally uniform tissue gap and a variable tissue gap) is created between the anvil 5102 and the auxiliary material 5106. In this illustrated embodiment, each substantially uniform tissue gap T _G occurs between the tissue compression surface 5112 of the anvil 5102 and the substantially planar surface 5127 of the tissue contacting surface 5118. Variable tissue gaps (only two variable gaps T _G1 , T _G2 ) occur between the tissue compression surface 5112 of the anvil 5102 and the non-planar surface 5129 of the tissue contacting surface 5118 that extends between adjacent unit cells of the second lattice structure 5126. One skilled in the art will appreciate that the length (extending in the x-direction) of the substantially uniform and variable tissue gaps may depend on at least the structural configuration of the tissue contacting surface and, therefore, the structural configuration of the second lattice structure.

While the heights between the repeating unit cells 5132a, 5132b, 5132c, 5134a, 5134b, 5134c are generally uniform, the wall thicknesses may differ, thus resulting in different compression ratios. In this illustrated embodiment, the three longitudinal arrays of the two sets are the same, and thus, for each set, the wall thickness W _T from the first repeating unit cell 5132a, 5134a (e.g., the innermost repeating unit cell) to the third repeating unit cell 5132c, 5134c (e.g., the outermost repeating unit cell) decreases in a similar manner. Thus, only one set of three longitudinal arrays is shown in FIG. 51B. The wall thickness W _T1 of the first repeat unit cell 5132a (not shown) is greater than the wall thickness W _T2 of the second repeat unit cell 5132b (e.g., middle repeat unit cell), which in _turn is greater than the wall thickness W _T3 of the third repeat unit cell 5132c, 5134c. As a result, the compression ratio from the first repeat unit cell 5132a, 5134a to the third repeat unit cell 5132c, 5134c increases, such that the first repeat unit cell 5132a, 5134a is the least compressed (e.g., most stiff) and the third repeat unit cell 5132c, 5134c is the most compressed (e.g., least stiff). That is, the first compression ratio of the first repeating unit cells 5132a, 5134a is less than each of the second and third compression ratios of the second and third repeating unit cells 5132b, 5134b, 5132c, 5134c, respectively, which second compression ratio is less than the third compression ratio. These compression ratios, in combination with the laterally differing compression ratios of the first lattice structure 5124, thus produce different overall compression ratios of the support material 5106 such that when the support material is stapled to tissue with substantially uniform (e.g., nominally identical within manufacturing tolerances) staples 5114a, 5114b, 5114c, 5116a, 5116b, 5116c, the support material 5106 is configured to apply a substantially uniform pressure to the stapled tissue for a predetermined period of time.

In certain embodiments, the first lattice structure may be configured to not overlap the rows of staples when the auxiliary material is releasably held on the staple cartridge. Thus, the first lattice structure is not captured, or is minimally captured, by the staples during deployment. As a result, the first lattice structure does not contribute, or contributes minimally, to the solid height of the auxiliary material when in a tissue-expanded state. Thus, densification of the auxiliary material may be delayed.

52A illustrates another exemplary embodiment of a surgical end effector 5200 having an anvil 5202 and a staple fastening assembly 5204. The staple fastening assembly 5204 includes a support 5206 that is releasably held on a top or deck surface 5208a of a staple cartridge 5208 (e.g., the cartridge surface facing the anvil). Other than the differences described below, the anvil 5202 and staple cartridge 5208 are similar to the anvil 5102 and staple cartridge 5208 of FIGS. 52A-B, and thus the common features will not be described in detail herein.

The support material 5204 is similar to the support material 5104 of FIGS. 51A-51B except that the first lattice structure 5224 is formed of two sets of four longitudinal rows of vertical planar struts spaced apart (e.g., in the x-direction) that extend between the second lattice 5226 structure and the top or deck surface 5208a of the staple cartridge 5208. As shown, the first set is positioned on one side of the intended cut line C _L of the support material 5206 and the second set is positioned at a second size of the intended cut line C of the support material 5206. For simplicity, only four struts 5228a, 5228b, 5228c, 5228d, 5230a, 5230b, 5230c, 5230d from each set are shown. The two sets of struts may have various configurations, but in this illustrated embodiment, the two sets of struts are the same, such that for each set, the first struts 5228a, 5230a (e.g., the struts in the innermost row) have a first height, the second struts 5228b, 5228b (e.g., the struts in the innermost middle row) have a second height that is greater than the first height, the third struts 5228c, 5230c (e.g., the struts in the outermost middle row) have a third height that is greater than the second height, and the fourth struts 5228d, 5230d (e.g., the struts in the outermost row) have a fourth height that is greater than the second height. Thus, the uncompressed thickness (e.g., in the y-direction, along the width of the support material) of the first lattice structure 5224 varies laterally relative to the longitudinal axis _LA of the support material 5206 (e.g., _LA extends in the z-direction). These lateral differences can be proportioned along the curved top or deck surface 5208a of the staple cartridge 5208 such that the portion of the cartridge contact surface 5220 of the support material 5206 formed by the bottom surface 5224b of the first lattice structure 5224 is complementary to the curved top or deck surface 5208a of the staple cartridge 5208 (e.g., a concave configuration). Thus, the variations in thickness of the first lattice structure 5224 can accommodate the variations in the top or deck surface 5208a.

52A, to minimize impact, the first lattice structure 5224 can have a densification of the support material 5206, and the first lattice structure 5224 can be designed not to overlap the staples 5214a, 5214a, 5214c, 5216a, 5216b, 5216c. For example, in this illustrated embodiment, none of the struts 5228a, 5228b, 5228c, 5228d, 5230a, 5230b, 5230c, 5230d overlap any of the staples 5214a, 5214b, 5214c, 5216a, 5216b, 5216c, so that the first lattice structure 5224 is not captured by the staples during deployment. As a result, when the support material 5206 is stapled to tissue, the pressure applied to the stapled tissue by the support material 5206 may depend entirely or substantially entirely on the compressive properties of the second lattice structure 5226.

In some embodiments, the wall thickness and height of each repeating unit cell may vary among other repeating unit cells. For example, FIG. 53 illustrates another exemplary embodiment of a support material 5300 that is releasably held on the top or deck surface 5302a (e.g., the cartridge surface facing the anvil) of a staple cartridge 5302. Other than the differences described in detail below, the staple cartridge 5302 is similar to the staple cartridge 5108 of FIGS. 51A-51B, and thus the common elements are not described in detail herein. As shown in FIG. 53, only one half (e.g., the right half) of the support material 5300 is shown on the staple cartridge 5302 having three rows of staples 5304, 5306, 5308 partially disposed therein, with the innermost staple row 5304 having the smallest staple height and the outermost staple row 5308 having the largest staple height. As noted above, differences in staple height can contribute to the overall compressive behavior of the support material when it is stapled to tissue.

Although the auxiliary material 5300 may have a variety of configurations, the auxiliary material 5300 is formed of interconnected repeating unit cells arranged in two sets of three longitudinal arrays, a first set positioned on one side of the intended cutting line C _L of the auxiliary material 5300, and a second set (not shown) positioned on a second side of the intended cutting line C _L of the auxiliary material 5300. Because both sets are identical, only one repeating unit cell 5310, 5312, 5314 of one set of three longitudinal arrays is shown in FIG.

The repeating unit cells 5310, 5312, 5314 can have a variety of configurations. In this illustrated embodiment, the repeating unit cells 5310, 5312, 5314 are similar in terms of overall shape, except that the wall thickness and height vary among the three repeating unit cells 5310, 5312, 5314. As shown, each repeat cell has a different height (e.g., in the X direction) from their respective outermost top surfaces 5310a, 5312a, 5314a that are laterally offset and aligned with one another in the y direction to their respective outermost bottom surfaces 5310b, 5312b, 5314b, and thus, for simplicity, minimum and maximum heights H _1A , H _1B for repeat unit cell 5310, minimum and maximum heights H _2A , H _2B for repeat unit cell 5312, and minimum and maximum heights H _3A , H _3B for repeat unit cell 5314 are shown.

As shown, a portion of the upper surface 5300a of the auxiliary material 5300 is generally planar and thus includes a generally planar surface 5316 (e.g., in each y direction) with a non-planar surface 5318 extending therebetween. The upper surface 5300a defines a tissue contacting surface 5320 of the auxiliary material 5300, and thus the tissue contacting surface 5320 is formed of the planar surface 5316 and the non-planar surface 5318. The generally planar surfaces 5316 and non-planar surfaces 5318 of the upper surface 5300a, and thus the tissue contacting surface 5320, alternate along the width of the auxiliary material 5300 (extending in the y direction), such that a consistent tissue gap (e.g., alternating between a generally uniform tissue gap and a variable tissue gap) is created between the anvil, such as the anvil 5102 of FIG. 51, and the auxiliary material 5300. In this illustrated embodiment, each substantially uniform tissue gap occurs between a tissue compression surface, such as the tissue compression surface 5112 of the anvil 5102 in FIG. 51, and a substantially planar surface 5316 of the tissue contact surface 5320. A variable tissue gap occurs between a tissue compression surface, such as the tissue compression surface 5112 of the anvil 5102 in FIG. 51, and a non-planar surface 5318 of the tissue contact surface 5320 that extends between adjacent unit cells of the support material 5300. One skilled in the art will appreciate that the length (extending in the x-direction) of the substantially uniform and variable tissue gaps may depend at least on the structural configuration of the tissue contact surface and, therefore, the structural configuration of the support material.

Furthermore, the wall thickness and height between at least two repeating units cells may be different, thus resulting in different compression ratios. In this illustrated embodiment, the wall thickness W T and H increase from the first repeating unit cell 5310 (e.g., the innermost repeating unit cell) to the third repeating unit cell _{5314 (e.g., the outermost repeating unit cell). That is, the wall thickness W T1 and} height H ₁ of the first repeating unit cell 5310 are smaller than the wall thickness W _T2 and height H ₂ of the second repeating unit cell 5312 (e.g., the middle repeating unit cell), which are smaller than the wall thickness W _T3 and _{height H 3 of} the third repeating unit cell 5314. As a result, the compression ratio decreases from the first repeating unit cell 5310 to the third repeating unit cell 5314. That is, the first compression ratio of the first repeating unit cell 5310 is greater than each of the second and third compression ratios of the second and third repeating unit cells 5312, 5314, respectively, and the second compression ratio is greater than the third compression ratio. These compression ratios thus generate different overall compression ratios of the support material 5300 such that when the support material is stapled to tissue with staples 5304, 5306, 5308 having different staple lengths (e.g., the innermost staple 5304 has the smallest staple height and the outermost staple 5308 has the largest staple height), the support material 5300 is configured to apply a generally uniform pressure to the stapled tissue for a predetermined period of time.

As discussed above, the support material may include a combination of strut-less based unit cells and strut-based unit cells and/or spacer struts. For example, FIG. 54 illustrates an exemplary embodiment of a support material 5400 releasably held on the top or deck surface 5402a (e.g., the cartridge surface facing the anvil) of a staple cartridge 5402. Other than the differences described in detail below, the staple cartridge 5402 is similar to the staple cartridge 200 of FIGS. 1-2C, and therefore the common elements are not described in further detail herein. As shown in FIG. 54, only half (e.g., the left half) of the support material 5400 is shown on the staple cartridge 5402 with three longitudinal rows 5303a, 5303b, 5303c of substantially uniform staples 5404a, 5404b, 5404c disposed therein.

Although the auxiliary material 5400 may have a variety of configurations, as shown, the auxiliary material has an internal lattice structure 5406 formed of two sets of two longitudinal arrays of repeating strutless unit cells, the first set positioned on one side of the intended cutting line C _L of the auxiliary material 5400, and the second set (not shown) positioned on the second side of the intended cutting line C _L of the auxiliary material 5400. Only one repeating unit cell 5408, 5410 of one set of two longitudinal arrays is shown in FIG. 54 because both sets are identical. Additionally, the auxiliary material 5400 includes structurally similar first and second outer lattice structures, positioned on either side of the internal lattice structure (only the first outer lattice structure 5412 is shown). Although only the first outer lattice structure 5412 and the first and second repeating unit cells 5408, 5410 of the support material 5400 are shown, a person skilled in the art will understand that the following discussion is also applicable to the second lattice structure and the second set of longitudinal array repeating cells.

The first and second repeating unit cells 5408, 5410 may have a variety of configurations. In this illustrated embodiment, the repeating unit cells 5408, 5410 are generally uniform (e.g., nominally identical within manufacturing tolerances) and structurally similar to the repeating unit cell 810 of FIGS. 9A-9B, and therefore the common features are not described in detail herein. As shown, the first and second repeating unit cells 5408, 5410 are oriented similarly to the repeating unit cell 4516 of FIGS. 45A-45C, and therefore the internal lattice structure 5406 may have a structurally similar configuration to the support material 4500 of FIGS. 45A-45C. As a result, the repeating unit cells 5408, 5410 are oriented (e.g., in a repeating pattern) such that the internal lattice structure 5406 may coincide with the position of the staples in one or more staple rows that overlap. As further shown, the first outer lattice structure 5412 includes pillar-based unit cells (only two unit cells 5414a, 5414b are shown in full). Although the pillar-based unit cells can have a variety of configurations, the first pillar-based unit cell 5414a has a triangular configuration and the second pillar-based unit cell 5414b has an inverted triangular configuration. As further shown, a portion of the second pillar-based unit cell 5414b intersects with the first pillar-based unit cell 5414a.

As shown, the lattice structures 5406, 5412 are adjacent to and laterally offset from one another relative to a longitudinal axis _LA of the support material 5400 (e.g., _LA extends in the z-direction). That is, the first outer lattice structure 5412 is positioned directly adjacent to the first longitudinal side 5406a of the internal lattice structure 5406. Further, the internal lattice structure 5406 overlaps the first and second staple rows 5403a, 5403b (e.g., the innermost and middle staple rows), respectively, and thus the first and second staples 5404a, 5404b, while the first outer lattice structure 5412 overlaps the third staple row 5404c (e.g., the outermost staple row), and thus the third staple 5404c. In this illustrated embodiment, the first repeating unit cells 5408 of the first longitudinal array and the second repeating unit cells 5410 of the second longitudinal array are staggered with respect to one another and thus oriented (e.g., in a repeating pattern) to coincide with the positions of the first and second staples 5404a, 5404b, respectively.

This alignment of the lattice structures 5406, 5412 relative to the first, second, and third lattice structures 5404a, 5404b, 5404c, in combination with the different structural configurations of the lattice structures 5406, 5412, can result in at least two different stress-strain curves when the support material is stapled to tissue. Given the orientation of the first and second repeating unit cells relative to the first and second staples, the resulting stress-strain curves of the support material at the first and second staples can be the same, or substantially the same. The compression behavior of the auxiliary material 5300 at each of the first staple, the second staple, and the third staple 5404a, 5404b, 5404c is shown diagrammatically in FIG. 55, where S1 represents the stress-strain curve of the auxiliary material at the first staple 5404a, S2 represents the stress-strain curve of the auxiliary material at the second staple 5404b, and S3 represents the stress-strain curve of the third staple 5404c. In this schematic diagram, the stress-strain curves S1 and S2 at the first staple and the second staple are shown as the same curve. Those skilled in the art will understand that the stress-strain curves at each staple may be different.

Auxiliary Material Systems Generally, the auxiliary material systems described herein may include at least two different auxiliary materials, each configured to undergo a respective strain in a respective strain range while under a respective applied stress in the range of about 30 kPa to 90 kPa. In some embodiments, the at least two respective strain ranges may at least partially overlap, while in other embodiments, the at least two respective ranges do not overlap. Additionally or alternatively, the combination of the respective strain ranges may result in a total range of at least 0.1 to 0.9. In other embodiments, the total range is at least about 0.1 to 0.8, about 0.1 to 0.7, about 0.1 to 0.6, about 0.1 to 0.5, about 0.1 to 0.4, about 0.1 to 0.5, about 0.1 to 0.6, about 0.1 to 0.8, about 0.1 to 0.9 ... The auxiliary material system may be about 0.3, about 0.2-0.8, about 0.2-0.7, about 0.3-0.7, about 0.3-0.8, about 0.3-0.9, about 0.4-0.9, about 0.4-0.8, about 0.4-0.7, about 0.5-0.8, or about 0.5-0.9. Although the auxiliary material system may include at least two different auxiliary materials, for the sake of brevity, the following description is for an auxiliary material system having only a first auxiliary material and a second auxiliary material. However, one of ordinary skill in the art will appreciate that the following discussion is also applicable to additional auxiliary materials in the auxiliary material system.

In some embodiments, the auxiliary material system may include a first auxiliary material and a second auxiliary material, where the first auxiliary material experiences a first range of strain while under an applied stress in the range of about 30 kPa to 90 kPa, and the second auxiliary material experiences a second range of strain while under an applied stress in the range of about 30 kPa to 90 kPa. The stress-strain response of each auxiliary material depends at least on the structural and compositional configurations of each auxiliary material. Thus, the first auxiliary material and the second auxiliary material may be tailored to provide a desired strain response under an applied stress and/or range of applied stresses. For example, in some embodiments, the first auxiliary material may be configured such that the first auxiliary material experiences a first range of strain of about 0.2-0.5 while under an applied stress in the range of about 60 kPa-90 kPa, and the second auxiliary material may be configured such that the second auxiliary material experiences a second range of strain of about 0.3-0.7 while under an applied stress in the range of about 40 kPa-70 kPa. In another embodiment, the first auxiliary material may be configured such that the first auxiliary material experiences a first range of strain of about 0.1-0.7 while under an applied stress in the range of about 30 kPa-90 kPa, and the second auxiliary material may be configured such that the second auxiliary material experiences a second range of strain of about 0.3-0.9 while under an applied stress in the range of about 30 kPa-90 kPa. In another embodiment, the first auxiliary material may be configured to undergo a first range of strain of about 0.2-0.6 while under an applied stress in the range of about 30 kPa-90 kPa, and the second auxiliary material may be configured to undergo a second range of strain of about 0.4-0.8 while under an applied stress in the range of about 30 kPa-90 kPa. In another embodiment, the first auxiliary material may be configured to undergo a first range of strain of about 0.1-0.7 while under an applied stress in the range of about 40 kPa-80 kPa, and the second auxiliary material may be configured to undergo a second range of strain of about 0.2-0.8 while under an applied stress in the range of about 30 kPa-90 kPa.

The first and second support materials may have various structural configurations. For example, the first support material may have a configuration similar to any one of the exemplary support materials described herein, and the second support material may have a different configuration than the first support material and may be similar to another one of the exemplary support materials described herein. In some embodiments, the first support material may be a non-strut-based support material and the second support material may be another non-strut-based support material or a strut-based support material described herein. In other embodiments, the first support material may be a strut-based support material and the second support material may be another strut-based support material or a non-strut-based support material.

In some embodiments, the first auxiliary material has a first internal structure formed of a first plurality of interconnected repeating unit cells, and the second auxiliary material has a second internal structure formed of a second plurality of interconnected repeating unit cells. In certain embodiments, the first plurality of interconnected repeating unit cells can be formed of a first material, and the second plurality of interconnected repeating unit cells can be formed of a second material different from the first material. The first and second materials can be any of the materials described herein and in more detail below. Additionally or alternatively, each unit of the first plurality of interconnected repeating unit cells has a first geometric shape, and each unit of the second plurality of interconnected repeating unit cells has a second geometric shape different from the first geometric shape.

In some embodiments, each unit cell of at least one of the first plurality of interconnected repeating unit cells and the second plurality of interconnected repeating unit cells is a triply periodic minimal surface structure (e.g., a Schwartzian P structure). In one embodiment, each unit cell of the first plurality of interconnected repeating unit cells is a first triply periodic minimal surface structure and each unit cell of the second plurality of interconnected repeating unit cells is a second triply periodic minimal surface structure that is different from the first triply periodic minimal surface structure. For example, the first triply periodic minimal surface structure and the second triply periodic minimal surface structure may differ in geometry, e.g., shape, size (e.g., height, wall thickness, etc.), or a combination thereof.

In some embodiments, each unit cell of the first plurality of interconnected repeating unit cells may include a first top portion formed from a first plurality of struts defining a first plurality of openings therebetween, a first bottom portion formed from a second plurality of struts defining a second plurality of openings therebetween, and a first spacer post interconnecting the first top portion and the first bottom portion. In such embodiments, each unit cell of the second plurality of interconnected repeating unit cells may be a Schwarz P structure. In other embodiments, each unit cell of the second plurality of interconnected repeating unit cells may include a second top portion formed from a third plurality of struts defining a third plurality of openings therebetween, a second bottom portion formed from a fourth plurality of struts defining a fourth plurality of openings therebetween, and a second spacer post interconnecting the second top portion and the second bottom portion.

Materials The support materials described herein may be formed of one or more polymers, such as bioabsorbable polymers, non-bioabsorbable polymers, bioabsorbable polymers, or any combination thereof. For clarity only, the use of "polymer" herein may be understood to include one or more polymers including one or more macromers. Non-limiting examples of suitable polymers include polylactide (PLA), polycaprolactone (PCL), polyglycolide (PGA), polydioxanone (PDO), polytrimethylene carbonate (PTMC), polyethylene glycol (PEG), polyethylene diglycolate (PEDG), polypropylene fumarate (PPF), poly(ethoxyethylene diglycolate), poly(ether ester) (PEE), poly(amino acids), poly(epoxy carbonate), poly(2-oxypropylene carbonate), poly(diol citrate), polymethacrylate anhydride, poly(N-isopropylacrylamide), copolymers thereof, or any combination thereof. Non-limiting examples of suitable copolymers include random copolymers such as PLGA-PCL, block copolymers such as poly(lactide-co-glycolide) (PLGA), triblock copolymers such as PLGA-PCL-PLGA or PLGA-PEG-PLGA, or any combination thereof. Further non-limiting examples of suitable polymers are disclosed, for example, in U.S. Pat. Nos. 9,770,241, 9,873,790, 10,085,745, and 10,149,753, and U.S. Patent Application Publication No. 2017/0355815, each of which is incorporated herein by reference in its entirety.

In some embodiments, the polymer may be formed of a resin. Generally, the resins described herein are suitable for use in additive manufacturing techniques such as bottom-up and top-down stereolithography, (b) produce a support material that is bioabsorbable, and/or (c) produce a support material that is flexible or elastic (e.g., at temperatures of about 25° C., about 37° C., and/or any temperature therebetween).

In some embodiments, the polymer may be formed from a photopolymerizable resin that includes an oligomeric prepolymer. The oligomeric prepolymer may be linear or branched (e.g., a "star" oligomer, such as a tri-arm oligomer). Non-limiting examples of suitable end groups for such oligomeric prepolymers include acrylate, methacrylate, fumarate, vinyl carbonate, methyl ester, ethyl ester, and the like. Suitable components of exemplary resins that may be used to form the polymers, and thus the auxiliary materials provided herein, are listed in Table 2 below. The components in each column of Table 2 may be combined with the components in the other columns in any combination.

While various types of resins may be used to form the polymer, in some embodiments, the polymer is formed from a resin based on a bioabsorbable polyester oligomer (e.g., a methacrylate-terminated oligomer having a bioabsorbable polyester linkage). For example, the bioabsorbable polyester oligomer may be present in an amount of about 5%-90%, 5%-80%, about 10%-90%, or about 10%-80% by weight of the resin. Unlike conventional resins (e.g., polycaprolactone dimethacrylate-based resins and poly(D,L-lactide) dimethacrylate-based resins), the resin may form a support that has rubber-like elastic behavior at physiological temperatures, short-term retention of mechanical properties (e.g., one month or less), and/or long-term complete absorption (e.g., over a period of about 4-6 months).

In some embodiments, the oligomer may include a linear oligomer. Alternatively or additionally, the oligomer may include a branched oligomer (e.g., a star-shaped oligomer, such as a tri-arm oligomer).

In some embodiments, the bioabsorbable polyester oligomers described herein are bioabsorbable oligomers having methacrylate end groups. Such oligomers typically include biodegradable ester linkages between components such as caprolactone, lactide, glycolide trimethylene carbonate, dioxanone, and propylene fumarate monomers in ABA blocks, BAB blocks, CBC blocks, BCB blocks, AB random compositions, BC random compositions, homopolymers, or any combination thereof, where A=poly(lactide) (PLA), poly(glycolide) (PGA), poly(lactide-co-glycolide) (PLGA), or polypropylene fumarate (PPF); B=polycaprolactone (PCL), poly(lactide-co-caprolactone) (PLACL), poly(glycolide-co-caprolactone) (PGACL), poly(trimethylene carbonate) (PTMC), or poly(caprolactone-co-lactide) (PCLLA); C=polydioxanone (PDO). The copolymers may have a molecular weight (Mn) of about 2 kilodaltons to 6 kilodaltons, about 2 kilodaltons to 10 kilodaltons, about 2 kilodaltons to 15 kilodaltons, about 2 kilodaltons to 20 kilodaltons, about 2 kilodaltons to 50 kilodaltons, about 5 kilodaltons to 6 kilodaltons, about 5 kilodaltons to 10 kilodaltons, about 5 kilodaltons to 15 kilodaltons, about 5 kilodaltons to 20 kilodaltons, about 5 kilodaltons to 50 kilodaltons, about 10 kilodaltons to 15 kilodaltons, about 10 kilodaltons to 20 kilodaltons, or about 10 kilodaltons to 50 kilodaltons, in either linear or star structures. The monomers used to generate such oligomers may optionally incorporate branching, such as, for example, gamma-methyl-epsilon-carboxylate and gamma-ethyl-epsilon-caprolactone, to enhance elasticity.

In some embodiments, the lactide may include L-lactide, D-lactide, or a mixture thereof (e.g., D,L-lactide). For example, in some embodiments having PLA blocks, L-lactide may be used for better ordering and higher crystallinity.

In some embodiments, the oligomers may include ABA, BAB, CBC, or BCB blocks in linear and/or branched (e.g., star-shaped or tri-arm) morphology.

In some embodiments, A can be (i) poly(lactide), (ii) poly(glycolide), (iii) poly(lactide-co-glycolide) containing lactide and glycolide in a molar ratio of 90:10 to 55:45 lactide:glycolide (e.g., lactide-rich ratio), 45:55 to 10:90 lactide:glycolide (e.g., glycolide-rich ratio), or 50:50 lactide:glycolide, or any combination thereof. In such embodiments, the oligomers can be linear and/or branched (e.g., star or tri-arm) in form. In some embodiments, D,L-lactide mixtures can be used to make PLGA random copolymers.

In some embodiments, B can be (i) polycaprolactone, (ii) polytrimethylene carbonate, (iii) poly(caprolactone-co-lactide) containing caprolactone and lactide in a molar ratio of caprolactone:lactide of 95:5 to 5:95, or any combination thereof.

In some embodiments, A (PLA, PGA, PLGA, PPF, or any combination thereof) may have a molecular weight (Mn) of about 1 kilodaltons to 4 kilodaltons, about 1 kilodaltons to 6 kilodaltons, about 1 kilodaltons to 10 kilodaltons, about 2 kilodaltons to 4 kilodaltons, about 2 kilodaltons to 6 kilodaltons, or about 2 kilodaltons to 10 kilodaltons, and B (PCL, PLACL, PGACL, PTMC, PCLLA, or any combination thereof) may have a molecular weight (Mn) of about 1 kilodalton to 4 kilodaltons, about 1 kilodalton to 6 kilodaltons, about 1 kilodalton to 10 kilodaltons, about 1 kilodalton to 50 kilodaltons, about 1.6 kilodaltons to 4 kilodaltons, about 1.6 kilodaltons to 6 kilodaltons, or about 1.6 kilodaltons to 10 kilodaltons, or about 1.6 kilodaltons to 50 kilodaltons.

The resin may also include additional components such as additional crosslinkers, non-reactive diluents, photoinitiators, reactive diluents, fillers, or any combination thereof.

In some embodiments, the resin may include an additional crosslinker. For example, the additional crosslinker may be present in an amount of about 1% to 5%, about 1% to 10%, about 2% to 5%, or about 2% to 10% by weight of the resin. Any suitable additional crosslinker may be used, including bioabsorbable crosslinkers, nonabsorbable crosslinkers, or any combination thereof. Non-limiting examples of suitable bioabsorbable crosslinkers include divinyladipate (DVA), poly(caprolactone) trimethacrylate (PCLDMA, e.g., with a molecular weight MW of about 950-2400 Daltons), and the like. Non-limiting examples of suitable nonabsorbable crosslinkers include trimethylolpropane trimethacrylate (TMPTMA), poly(propylene glycol) dimethacrylate (PPGDMA), poly(ethylene glycol) dimethacrylate (PEGDMA), and the like.

In some embodiments, the resin may include a non-reactive diluent. For example, the non-reactive diluent may be present in an amount of about 1% to 70%, about 1% to 50%, about 5% to 70%, or about 5% to 50% by weight of the resin. Non-limiting examples of non-reactive diluents include dimethylformamide, dimethylacetamide, N-methylpyrrolidone (NMP), dimethylsulfoxide, cyclic carbonates (e.g., propylene carbonate), diethyl adipate, methyl ether ketone, ethyl alcohol, acetone, or any combination thereof.

In some embodiments, the system may include a photoinitiator. For example, the photoinitiator may be present in an amount of about 0.1% to 4%, about 0.1% to 2%, about 0.2% to 4%, or about 0.2% to 2% by weight of the resin. The photoinitiator included in the resin may be any suitable photoinitiator. Non-limiting examples of suitable photoinitiators include Type I and Type II photoinitiators, and UV photoinitiators (e.g., acetophenone (e.g., diethoxyacetophenone), phosphine oxides (e.g., diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl), phosphine oxide (PPO), Irgacure® 369), and the like. Exemplary photoinitiators may be found in U.S. Pat. No. 9,453,142, the entirety of which is incorporated herein by reference.

In one embodiment, the resin may include a bioabsorbable polyester oligomer that may be present in an amount of about 5% to 90%, 5% to 80%, about 10% to 90%, or about 10% to 80% by weight of the resin, a non-reactive diluent that may be present in an amount of about 1% to 70%, about 1% to 50%, about 5% to 70%, or about 5% to 50% by weight of the resin, and a photoinitiator that may be present in an amount of about 0.1% to 4%, about 0.1% to 2%, about 0.2% to 4%, or about 0.2% to 2% by weight of the resin.

In some embodiments, the resin may include reactive diluents (including difunctional and trifunctional reactive diluents). For example, the reactive diluent may be present in an amount of about 1% to 50%, about 1% to 40%, about 5% to 50%, or about 5% to 40% by weight of the resin. Non-limiting examples of reactive diluents include acrylates, methacrylates, styrenes, vinyl amides, vinyl ethers, vinyl esters, polymers containing one or more of the foregoing, or any combination thereof (e.g., acrylonitrile, styrene, divinylbenzene, vinyl toluene, methyl acrylate, ethyl acrylate, butyl acrylate, methyl (meth)acrylate, isobornyl acrylate (IBOA), isobornyl methacrylate (IBOMA), alkyl ethers of mono-, di-, or triethylene glycol acrylate or methacrylate, aliphatic alcohol acrylates, methacrylates such as lauryl (meth)acrylate, or mixtures thereof).

In one embodiment, the resin may include a bioabsorbable polyester oligomer that may be present in an amount of about 5% to 90%, about 5% to 80%, about 10% to 90%, or about 10% to 80% by weight of the resin; a non-reactive diluent that may be present in an amount of about 1% to 70%, about 1% to 50%, about 5% to 70%, or about 5% to 50% by weight of the resin; a photoinitiator that may be present in an amount of about 0.1% to 4%, about 0.1% to 2%, about 0.2% to 4%, or about 0.2% to 2% by weight of the resin; and a photoinitiator that may be present in an amount of about 1% to 50%, about 1% to 40%, about 5% to 50%, or about 5% to 40% by weight.

In some embodiments, the resin may include a filler. For example, the filler may be present in an amount of about 1% to 50%, about 1% to 40%, about 2% to 50%, or about 2% to 40% by weight of the resin. Any suitable filler may be used in connection with the present invention, including, but not limited to, bioabsorbable polyester particles, sodium chloride particles, calcium triphosphate particles, sugar particles, and the like.

In one embodiment, the resin comprises a bioabsorbable polyester oligomer, which may be present in an amount of about 5% to 90%, about 5% to 80%, about 10% to 90%, or about 10% to 80% by weight of the resin; a non-reactive diluent, which may be present in an amount of about 1% to 70%, about 1% to 50%, about 5% to 70%, or about 5% to 50% by weight of the resin; and a non-reactive diluent, which may be present in an amount of about 0.1% to 4%, about 0.1% to 2%, or about 0.2% to 2% by weight of the resin. %, about 0.2% to 4% by weight, or about 0.2% to 2% by weight; a reactive diluent that may be present in an amount of about 1% to 50% by weight, about 1% to 40% by weight, about 5% to 50% by weight, or about 5% to 40% by weight of the resin; and a filler that may be present in an amount of about 1% to 50% by weight, about 1% to 40% by weight, about 2% to 50% by weight, or about 2% to 40% by weight of the resin.

Further, depending on the particular use of the supplement, in some embodiments, the resin may have additional components. For example, in certain embodiments, the resin may include one or more additional components that may be present in an amount of about 0.1% to 10% by weight of the resin, about 0.1% to 10% by weight of the resin, about 1% to 20% by weight of the resin, or about 1% to 10% by weight of the resin. Non-limiting examples of suitable additional components include pigments, dyes, diluents, active or pharmaceutical compounds, detectable (e.g., fluorescent, phosphorescent, radioactive) compounds, proteins, peptides, nucleic acids (DNA, RNA) such as siRNA, sugars, and the like, including any combination thereof.

In some embodiments, the resin may include a non-reactive pigment or dye that absorbs light, particularly UV light. Non-limiting examples of suitable non-reactive pigments or dyes include (i) titanium dioxide (e.g., present in an amount of about 0.05% to 5%, about 0.05% to 1%, about 0.1% to 1%, or about 0.1% to 5% by weight of the resin), (ii) carbon black (e.g., present in an amount of about 0.05% to 5%, about 0.05% to 1%, about 0.1% to 1%, or about 0.1% to 5% by weight of the resin), and/or (iii) organic UV absorbers such as hydroxybenzophenones, hydroxyphenylbenzotriazoles, oxanilides, benzophenones, thioxanthones, hydroxyphenyltriazines, and/or benzotriazole UV absorbers (e.g., Mayzo BLS1326) (e.g., present in an amount of about 0.001% to 1%, 0.001% to 2%, about 0.001% to 4%, about 0.005% to 1%, about 0.005% to 2%, or about 0.005% to 4% by weight of the resin). Additional exemplary non-reactive pigments or dyes are disclosed in U.S. Pat. No. 3,213,058, U.S. Pat. No. 6,916,867, U.S. Pat. No. 7,157,586, and U.S. Pat. No. 7,695,643, each of which is incorporated herein by reference in its entirety.

In some embodiments, the resin comprises: (a) a (meth)acrylate-terminated bioresorbable polyester oligomer present in an amount of about 5% to 80%, about 5% to 90%, about 10% to 80%, or about 10% to 90% by weight of the resin; (b) a non-reactive diluent present in an amount of about 1% to 50%, about 1% to 70%, about 5% to 50%, or about 5% to 70% by weight of the resin; and (c) a photoinitiator present in an amount of about 0.1% to 2%, about 0.1% to 4%, about 0.2% to 2%, or about 0.2% to 4% by weight of the resin. In such embodiments, the resin also comprises: (d) a reactive diluent present in an amount of about 1% to 40%, about 1% to 50%, about 5% to 40%, or about 5% to 50% by weight of the resin; (e) a filler present in an amount of about 1% to 40%, about 1% to 50%, about 2% to 40%, or about 2% to 50% by weight of the resin; (f) a filler present in an amount of about 0.1% to 10%, about 0.1% to 20%, about 0.1% to 20% by weight of the resin; 20% by weight, about 1% to 10% by weight, or about 1% to 20% by weight of the resin (e.g., an activator, detectable group, pigment, or dye, etc.), and/or (g) an additional crosslinker (e.g., trimethylolpropane trimethacrylate (TMPTMA)) present in an amount of about 1% to 5% by weight, about 1% to 10% by weight, about 2% to 5% by weight, or about 2% to 10% by weight of the resin.

In some embodiments, the resin is
(a) a (meth)acrylate terminated, linear or branched, bioabsorbable polyester oligomer of monomers in an ABA block, a BAB block, a CBC block, or a BCB block, the oligomer being present in an amount of about 5% to 80%, about 5% to 90%, about 10% to 80%, or about 10% to 90% by weight of the resin; A is poly(lactide) (PLA), poly(glycolide) (PGA), poly(lactide-co-glycolide) (PLGA), or any combination thereof, where PLGA contains lactide and glycolide in a molar ratio of either 90:10 to 60:40 lactide:lactide, or 40:60 to 10:90 lactide; A is about 1 kilodaltons to 4 kilodaltons, about 1 kilodaltons to 10 kilodaltons, about 2 kilodaltons to 4 kilodaltons, about 3 kilodaltons to 5 kilodaltons, about 4 kilodaltons to 6 kilodaltons, about 5 kilodaltons to 8 kilodaltons, about 6 kilodaltons to 9 kilodaltons, about 7 kilodaltons to 10 kilodaltons, about 8 kilodaltons to 10 kilodaltons, about 9 kilodaltons to 10 kilodaltons, about 10 kilodaltons to 10 kilodaltons, about 2 kilodaltons to 4 kilodaltons, about 10 kilodaltons to 10 kilodaltons, about 2 kilodaltons to 10 kilodaltons, about 3 kilodaltons to 10 kilodaltons, about 4 kilodaltons to 10 kilodaltons, about 5 kilodaltons to 10 kilodaltons, about 6 kilodaltons to 10 kilodaltons, about 7 kilodaltons to 10 kilodaltons, about 8 kilodaltons to 10 kilo B is a polycaprolactone (PCL, PTMC, and PCLLA), poly(lactide-co-caprolactone) (PLACL), poly(glycolide-co-caprolactone) (PGACL), or poly(trimethylene carbonate) (PTMC) having a molecular weight (Mn) of about 1 kilodaltons to 4 kilodaltons, about 1 kilodaltons to 10 kilodaltons, about 1.6 kilodaltons to 4 kilodaltons, or about 1.6 kilodaltons to 10 kilodaltons; and C is a polydioxanone (PDO) having a molecular weight (Mn) of about 1 kilodaltons to 4 kilodaltons, about 1 kilodaltons to 10 kilodaltons, about 2 kilodaltons to 4 kilodaltons, or about 2 kilodaltons to 10 kilodaltons.
(b) propylene carbonate present in an amount of about 1% to 50%, about 1% to 70%, about 5% to 50%, or about 5% to 70% by weight of the resin; and
(c) a photoinitiator present in an amount of about 0.1% to 2%, about 0.1% to 4%, about 0.2% to 2%, or about 0.2% to 4% by weight of the resin; and
(d) optionally a reactive diluent present in an amount of about 1% to 40%, about 1% to 50%, about 5% to 40%, or about 5% to 50% by weight of the resin;
(e) optionally, a filler present in an amount of about 1% to 40%, about 1% to 50%, about 2% to 40%, or about 2% to 50% by weight of the resin.

Methods of Manufacture The non-fibrous support materials described herein may be formed from a matrix including at least one fused bioabsorbable polymer, and therefore may be formed using any additive manufacturing process. In some embodiments, the additive manufacturing process may be continuous liquid interface production (CLIP), which involves curing a liquid plastic resin using ultraviolet light. Details of the CLIP process can be found, for example, in U.S. Pat. Nos. 9,211,678, 9,205,601, and 9,216,546, U.S. Patent Application Publication Nos. 2017/0129169, 2016/0288376, 2015/0360419, 2015/0331402, 2017/0129167, 2018/0243976, 2018/0126630, and 2018/0290374, J. Med. Soc. Tumbleston et al., Continuous liquid interface production of 3D Objects, Science 347, 1349-1352 (2015), and R. Janusziewcz et al., Layerless fabrication with continuous liquid interface production, Proc. Natl. Acad. Sci. USA 113:11703-11708 (2016), each of which is incorporated herein by reference in its entirety. Non-limiting examples of other additive manufacturing devices and methods that may be used to form the non-fibrous supplementary materials described herein, and thus matrices comprising at least one fused bioabsorbable polymer, include bottom-up and top-down additive manufacturing methods such as those described in, for example, U.S. Pat. Nos. 5,236,637, 5,391,072, 5,529,473, 7,438,846, 7,892,474, and 8,110,135, which are incorporated by reference herein in their entireties, and U.S. Patent Application Publication Nos. 2013/0292862 and 2013/0295212, as well as fused deposition modeling (e.g., heating a thermoplastic filament and extruding the molten filament layer by layer), material jetting, two-photon polymerization, and holographic multi-focal polymerization, as would be understood by one of ordinary skill in the art.

In certain embodiments, one or more post-processing steps may be performed after the additive manufacturing process. For example, in some embodiments, the one or more post-processing steps may include washing the auxiliary material (e.g., in an organic solvent such as acetone, isopropanol, a glycol ether such as propylene glycol methyl ether, or DPM), wiping the auxiliary material (e.g., blowing with an absorbent material, such as with a compressed gas or air blade), centrifuging the residual resin, extracting the residual solvent, additional curing such as by flood exposure with ultraviolet light to further react unpolymerized components of the auxiliary material, drying the auxiliary material (e.g., under vacuum) to remove the extraction solvent, or any combination thereof, according to known techniques. One or more post-processing steps may cause the auxiliary material to shrink, and thus, in some embodiments, the auxiliary material may be manufactured in an enlarged form to offset such shrinkage.

In other embodiments, the non-fibrous auxiliary material may be partially or wholly formed using any suitable non-additive manufacturing process, such as injection molding, foaming, and forming processes, as will be appreciated by those skilled in the art.

The staple fastening assembly may be manufactured in a variety of ways. For example, in some embodiments, as described above, the non-fibrous auxiliary material may be releasably attached to the staple cartridge by positioning a cartridge contact surface of the auxiliary material against a surface of the cartridge (e.g., an anvil-facing surface, e.g., a top surface or deck surface) thereby inserting at least one attachment feature of the auxiliary material into at least one surface feature (e.g., a recessed channel) of the cartridge (see, e.g., FIGS. 19A-26C, 37A-39B, and 41A-41C). Alternatively or additionally, as described above, the non-fibrous auxiliary material may be configured to receive one or more cartridge projections (e.g., staple pocket projections) and/or staple legs (see, e.g., FIGS. 45A-46B). Additional details regarding surface features and other exemplary surface features may be found in U.S. Patent Publication No. 2016/0106427, which is incorporated herein by reference in its entirety. Alternatively or additionally, as discussed above, the non-fibrous support material may include an outer layer in the form of an adhesive film used to releasably hold the support material to the staple cartridge (see, e.g., FIG. 40). Additional details regarding adhesive films and other attachment methods may be found in U.S. Pat. No. 10,349,939, which is incorporated herein by reference in its entirety.

The materials and methods can be further understood from the following non-limiting examples.

Examples 1-3: Preparation of difunctional methacrylate (MA) terminated polyester oligomers Examples 1-3 describe the preparation of difunctional methacrylate terminated polyester oligomers. The midblock is PLGA-PCL-PLGA with a molecular weight of 6 kilodaltons and PCL included as 40% by weight of the total molecular weight (MW). PLGA is a random copolymer of lactide (L) and glycolide (G) with a 1:1 L:G weight ratio.

The molar ratios and masses of each reagent used for a 1 kg batch of HO-PLGA-b-PCL-b-PLGA-OH synthesis as discussed in Examples 1 and 2 are provided in Table 3 below.

Example 1: HO-PCL-OH Synthesis A round bottom flask was dried overnight in a drying oven and cooled to room temperature under _N2 flow. Caprolactone and stannous octoate were added to the round bottom flask via a glass syringe and syringe needle. The contents of the reaction flask were heated to 130°C. Meanwhile, diethylene glycol was heated to 130°C. Once preheated, diethylene glycol was added to the reaction flask as an initiator and allowed to react until complete monomer conversion. Monomer conversion was monitored using ^H1 NMR. Once complete monomer conversion was reached, the reaction was stopped and the reaction contents were allowed to cool to room temperature. HO-PCL-OH was precipitated from chloroform into cold MeOH to give a white solid. HO-PCL-OH was characterized using ^H1 NMR, DSC, FTIR, and THF GPC.

Example 2: HO-PLGA-b-PCL-b-PLGA-OH synthesis HO-PCL-OH prepared in Example 1 and different amounts of D,L-lactide and glycolide were added to a round bottom flask under _N2 and heated to 140°C to melt the reaction contents. After melting, the temperature was reduced to 120°C and stannous octoate was added. The reaction was continued with stirring while monitoring the monomer conversion by ^H1 NMR and THF GPC. Once the reaction reached the desired molecular weight, the reaction contents were cooled to room temperature, dissolved in chloroform, and precipitated into cold diethyl ether three times. The precipitate was dried under vacuum.

Example 3: MA-PLGA-b-PCL-b-PLGA-MA Synthesis The molar ratios and masses of each reagent used to synthesize a 1 kg batch of MA-PLGA-b-PCL-b-PLGA-MA are provided in Table 4 below.

HO-PLGA-b-PCL-b-PLGA-OH prepared in Example 2 was dissolved in anhydrous DCM in a round bottom flask under _N2 . Triethylamine and BHT were added to the reaction flask and the reaction flask was cooled to 0°C in an ice water bath. The reaction flask was equipped with a pressure equalizing addition funnel charged with methacryloyl chloride. Once the reaction flask reached 0°C, methacryloyl chloride was added dropwise over 2 hours. The reaction was allowed to proceed at 0°C for 12 hours and then at room temperature for 24 hours. Upon completion, the reaction contents were washed twice with distilled _water to remove triethylamine hydrochloride, washed with saturated _Na2CO3 , and then dried over magnesium sulfate. The collected and dried DCM layer was dried by rotary evaporation. The final product was characterized by THF GPC, ^H1 NMR, FTIR, and DSC.

Examples 4-6: Preparation of a Tri-Arm MA-Terminated Polyester Oligomer Examples 4-6 describe the preparation of a tri-arm, or star-shaped, bioabsorbable polyester oligomer. Each arm is terminated with a methacrylate. Each arm has a molecular weight of 2 kilodaltons and is a block copolymer of random poly(lactide-co-glycolide) (PLGA) segments and poly(caprolactone) (PCL) segments, with PCL being the core of the oligomer. PCL is included as 40% by weight of the total molecular weight (MW). PLGA is a random copolymer of lactide (L) and glycolide (G) with a 1:1 L:G weight ratio.

Example 4: PCL-3OH Synthesis The molar ratios and masses of each reagent used in a 1 kg batch of (PLGA-b-PCL)-3OH synthesis as discussed in Examples 4 and 5 are provided in Table 5 below.

The round bottom flask was dried overnight in a drying oven and cooled to room temperature under _N2 flow. Caprolactone and stannous octoate were added to the round bottom flask via a glass syringe and syringe needle. The contents of the reaction flask were heated to 130°C. Meanwhile, trimethylolpropane (TMP) was heated to 130°C. Once preheated, TMP was added to the reaction flask as an initiator and allowed to react until complete monomer conversion. Monomer conversion was monitored using ^H1 NMR. Once complete monomer conversion was reached, the reaction was stopped and the reaction contents were allowed to cool to room temperature. (PCL)-3OH was precipitated from chloroform into cold MeOH to give a white solid. (PCL)-3OH was characterized using H1 NMR, DSC, FTIR, and GPC.

Example 5: (PCL-b-PLGA)-3OH Synthesis (PCL)-3OH prepared in Example 4 and different amounts of D,L-lactide and glycolide were added to a round bottom flask under _N2 and heated to 140°C to melt the reaction contents. Once melted, the temperature was reduced to 120°C and stannous octoate was added. The reaction was continued with stirring while monitoring the monomer conversion by ^H1 NMR and THF GPC. Once the reaction reached the desired molecular weight, the reaction contents were cooled to room temperature, dissolved in chloroform, and precipitated into cold diethyl ether three times. The precipitate was dried under vacuum.

Example 6: (PCL-b-PLGA)-3MA Synthesis The molar ratios and masses of each reagent used to synthesize a 1 kg batch of (PLGA-b-PCL)-3MA are provided in Table 6 below.

(PCL-b-PLGA)-3OH prepared in Example 5 was dissolved in anhydrous DCM in a round bottom flask under _N2 . Triethylamine (TEA) and BHT were added to the reaction flask and the reaction flask was cooled to 0°C in an ice water bath. The reaction flask was equipped with a pressure equalizing addition funnel charged with methacryloyl chloride. Once the reaction flask reached 0°C, methacryloyl chloride was added dropwise over 2 hours. The reaction was allowed to proceed at 0°C for 12 hours and then at room temperature for 24 hours. Upon completion, the precipitate was removed by vacuum filtration. The filtrate was collected and the DCM was removed by rotary evaporation. The resulting viscous oil was dissolved in THF and precipitated into cold methanol. The precipitate was dissolved in DCM and washed with aqueous HCl (3%, twice), saturated aqueous sodium bicarbonate, and saturated aqueous sodium chloride, then dried over magnesium sulfate. The magnesium sulfate was filtered off by vacuum filtration and the filtrate was collected. The DCM was removed by rotary evaporation and the solid product was collected and characterized by GPC, H ¹ NMR, FTIR, and DSC.

Example 7: Difunctional oligomer resin formulation The following components were mixed together in the following weight percentages (% by weight of resin) to provide an exemplary resin for additive manufacturing.
(1) 66.2% of the bifunctional oligomer prepared in Examples 1 to 3 above
(2) Trimethylolpropane triacrylate (TMPTMA) reactive diluent 3.5%
(3) N-methylpyrrolidone (NMP) non-reactive diluent 28.4%
(4) Irgacure® 819 photoinitiator 1.89%

Example 8: Tri-Arm Oligomer Resin Formulation The following components were mixed together in the following weight percentages (% by weight of resin) to provide an exemplary resin for additive manufacturing.
(1) 68.6% of the tri-arm oligomer prepared in Examples 4 to 6 above
(2) N-methylpyrrolidone (NMP) non-reactive diluent 29.4%
(3) Irgacure® 819 photoinitiator 1.96%

Example 9: Additive Manufacturing and Post-Processing Five exemplary auxiliary materials were prepared. The first exemplary auxiliary material (auxiliary material 1) was structurally similar to auxiliary material 800 of Figures 8A-8F, except that the first auxiliary material was formed with two longitudinal rows of 20 unit cells. The four other exemplary auxiliary materials were structurally similar to auxiliary materials 3100, 3200, 3300, 3400, as shown in Figures 31A-31D (auxiliary material 2), 32A-32D (auxiliary material 3), 33A-33E (auxiliary material 4), and 34A-34E (auxiliary material 5), respectively. The five auxiliary materials were prepared according to standard techniques using carbon fiber composites available from Carbon Inc., 1089 Mills Way, Redwood City California, 94063. The resin formulations for each additive were prepared by additive manufacturing performed on an M1 or M2 machine.

When the resin contains non-reactive diluents, the object may experience overall shrinkage upon cleaning/extraction depending on the extent of the non-reactive diluent loading. Therefore, a dimensional scaling factor is applied to the part stereolithography (.stl) file or 3D manufacturing format (3MF) file to enlarge the printed support material and intentionally account for subsequent shrinkage during post-processing steps.

Post-treatment of each auxiliary was performed as follows: after removing the build platform from the apparatus, excess resin was wiped off the flat surface around the auxiliary and the platform was left on its side to drain for approximately 10 minutes. The auxiliary was carefully removed from the platform. The auxiliary was washed with acetone three times for 30 seconds each on an orbital shaker at 280 rpm, followed by drying for 5 minutes between washes. After the third wash, the auxiliary was allowed to dry for 30 minutes and then flood cured in a PrimeCure™ UV flood cure apparatus for 20 seconds per side.

Residual non-reactive diluents (e.g., N-methylpyrrolidone or propylene carbonate) were then extracted from the supplement by immersing the supplement in acetone and shaking on an orbital shaker at room temperature for approximately 18 hours with one solvent exchange after 12 hours. The supplement was then removed from the acetone and vacuum dried overnight at 60°C. The supplement was then checked for residual solvent using extraction vs. GCMS and FTIR. If no residue was detected, the parts were checked for tackiness. If the supplement remained tacky, it was flood cured under nitrogen in an LED-based flood lamp (such as a PCU LED N2 flood lamp available from Dreve Group, Unna, Germany).

Example 10: Stress-strain analysis of representative samples The stress-strain curve of auxiliary material 1 of Example 9 is shown in FIG. 56, and the stress-strain curves of auxiliary materials 2 to 5 of Example 9 are shown in FIG.

The stress-strain curves shown in Figures 56 and 57 were generated by positioning the supplemental material between a pair of 25 millimeter diameter circular stainless steel compression plates on an RSA-G2 solids analyzer (available from TA Instruments, 159 Lukens Drive, New Castle, Delaware 19720 USA), lowering the compression plate at 0.1 mm steps until an initial axial force of 0.03-0.05 N was encountered, equilibrating at a temperature of 37°C for 120 seconds, and running a compression test (lowering the compression plate at 10 mm/min for 14 seconds until a gap height of 0.7 mm or a load force of approximately 17 N was reached while recording real-time compression stress) to generate a stress-strain curve for each supplemental material. Thus, the stress-strain curves were generated by compressing each supplemental material from its respective uncompressed height of 3 mm to its respective compressed height. The compression height and strain of each auxiliary material while it is under the applied stress are provided below in Table 8. These measurements are based on the actual manufactured auxiliary material (including any measurement error of the measurement system, e.g., bias from 50 μm to the uncompressed height, and/or manufacturing tolerances, e.g., bias from 100 μm to the uncompressed height).

As shown in FIG. 56, a support material formed with a strut-free based unit cell, such as the support material 800 of FIGS. 8A-8F, has been demonstrated to: (i) be a unit structure that is sufficiently stable even with a wall thickness of about 0.2 millimeters, and the structure can be successfully printed and post-processed as described above; (ii) the support material undergoes a wide range of buckling deformations, achieving a stress plateau of about 0.1 strain (about 10% deformation) to about 0.73 strain (73% deformation); and (iii) the support material is bi-stable in nature, such that the unit structure can deform and achieve a new stable form that does not change until additional force is applied, providing the surgeon with tactile feedback of the deformation state of the support material.

As shown in FIG. 57, the support material formed with the support-based strut unit cells, e.g., the support material 3100 of FIGS. 31A-31D, the support material 3200 of FIGS. 32A-32D, the support material 3300 of FIGS. 33A-33E, and the support material of FIGS. 34A-34E, exhibited stress "plateaus" within 5 kPa to 20 kPa of stress over strains of 10 to 60 percent. This result is based, at least in part, on the structural configuration of the unit cells. In particular, each unit cell is designed such that the spacer struts (e.g., internal structural struts) fold inwardly without contacting each other during compression of the support material. As a result, densification (e.g., reaching a solid height) of the support material can be delayed (e.g., occurring at higher strains).

Example 11: Stress-Strain Analysis of Representative Samples Six exemplary auxiliary materials, referred to herein as Sample 1, Sample 2, Sample 3, Sample 4, Sample 5, and Sample 6, were each prepared in a manner similar to Example 9, except that the resin formulation for each of Samples 1-6 was a trifunctional oligomer (methacrylate end groups) with a PCL midblock and PLGA endblocks (85/15 L:G ratio) with a target molecular weight of 6,000 Daltons. Sample 1 was formed from repeating interconnected Schwartzian P structure unit cells, and Samples 2-5 were formed from respective repeating interconnected modified Schwartzian P structures where the top and/or bottom of the initial Schwartzian P structure was cropped. Thus, the geometric properties of the repeating unit cells of each sample were different. A list of the geometric unit cell properties for each auxiliary material is provided below in Table 9, which is based on theoretical/intended size.

The stress-strain curves for Samples 1-6 were generated in a manner similar to that described in Example 10 and are shown in FIG. 58. As shown, each unit cell was formed with the same resin, but each sample had a different stress-strain curve. These different stress-strain curves thus show the relationship between the geometric properties (e.g., height, width, length, and wall thickness) of the unit cells and the resulting stress-strain response of the auxiliary material from its respective uncompressed height (listed as the overall height in Table 9 above) to its respective compressed height. Thus, in addition to the compositional makeup of the unit cells, the various geometric properties thereof must be taken into account and therefore tailored to result in an auxiliary material having a desired stress-strain response, such as the stress-strain response described herein. The compression height and strain for each sample while the sample was under an applied stress of 90 kPa are provided in Table 10 below. These measurements are based on the actual manufactured support material (including any measurement errors of the measurement system, e.g., bias from 50 μm to the uncompressed height, and/or manufacturing tolerances, e.g., bias from 100 μm to the uncompressed height).

Examples 12-14: Preparation of a Tri-Arm MA-Terminated Polyester Oligomer Examples 12-14 describe the preparation of a tri-arm, or star-shaped, bioabsorbable polyester oligomer. Each arm is terminated with a methacrylate. Each arm has a molecular weight of 2 kilodaltons and is a block copolymer of poly(L-lactic acid) (PLLA) and poly(caprolactone-r-L-lactic acid) (PCLLA), with PCLLA being the core of the oligomer. PCLLA is included as 70% by weight of the total molecular weight (MW) and CL, with a CL:L ratio of 60:40.

The molar ratios and masses of each reagent used for a 1 kg batch of (PLLA-b-PCLLA)-3OH synthesis as discussed in Examples 12 and 13 are provided in Table 11 below.

Example 12: PCLLA-3OH Synthesis A round bottom flask was dried overnight in a drying oven and cooled to room temperature under _N2 flow. Caprolactone, L-lactide, and stannous octoate were added to the round bottom flask. The contents of the reaction flask were heated to 130°C. Meanwhile, trimethylolpropane (TMP) was heated to 130°C. Once preheated, TMP was added to the reaction flask as an initiator and allowed to react until complete monomer conversion. Monomer conversion was monitored using ^H1 NMR. Once complete monomer conversion was reached, the reaction was stopped and the reaction contents were allowed to cool to room temperature. (PCLLA)-3OH was precipitated from chloroform into cold MeOH to obtain a white solid. (PCLLA)-3OH was characterized using ^H1 NMR, DSC, FTIR, and THF GPC.

Example 13: (PLLA-b-PCLLA)-3OH Synthesis (PCLLA)-3OH prepared in Example 12 and L-lactide were added to a round bottom flask under _N2 and heated to 140°C to melt the reaction contents. Once melted, the temperature was reduced to 120°C and stannous octoate was added. The reaction was continued with stirring while monitoring the monomer conversion by ^H1 NMR and THF GPC. Once the reaction reached the desired molecular weight, the reaction contents were cooled to room temperature, dissolved in chloroform and precipitated into cold diethyl ether three times. The precipitate was dried under vacuum.

Example 14: (PLLA-b-PCLLA)-3MA synthesis The molar ratios and masses of each reagent used to synthesize a 1 kg batch of (PLLA-b-PCLLA)-3MA are provided in Table 12 below.

(PLLA-b-PCLLA)-3OH prepared in Example 13 was dissolved in anhydrous DCM in a round bottom flask under _N2 . Triethylamine (TEA) and 400 ppm of BHT were added to the reaction flask and the reaction flask was cooled to 0°C in an ice water bath. The reaction flask was equipped with a pressure equalizing addition funnel charged with methacryloyl chloride. Once the reaction flask reached 0°C, methacryloyl chloride was added dropwise over 2 hours. The reaction was allowed to proceed at 0°C for 12 hours and then at room temperature for 24 hours. Upon completion, the precipitate was removed by vacuum filtration. The filtrate was collected and the DCM was removed by rotary evaporation. The resulting viscous oil was dissolved in THF and precipitated into cold methanol. The precipitate was dissolved in DCM and washed with aqueous HCl (3%, twice), saturated aqueous sodium bicarbonate, and saturated aqueous sodium chloride, then dried over magnesium sulfate. The magnesium sulfate was filtered off by vacuum filtration and the filtrate was collected. The DCM was removed by rotary evaporation and the solid product was collected and characterized by THF GPC, H ¹ NMR, FTIR, and DSC.

Example 15: Difunctional Oligomer Resin Formulation The following components were mixed together in the following weight percentages (% by weight of resin) to provide an exemplary photopolymerizable resin for additive manufacturing.
(1) 58.82% difunctional oligomer prepared in Examples 12-13 above
(2) Propylene carbonate (PC) non-reactive diluent 39.22%
(3) Irgacure® 819 photoinitiator 1.96%

The instruments disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the instrument can be reconditioned after at least one use and reused. Reconditioning can include any combination of the steps of disassembly of the instrument, followed by cleaning or replacement of particular parts, and subsequent reassembly. In particular, the instrument can be disassembled and any number of particular parts or pieces of the instrument can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the instrument can be reassembled for later use at a reconditioning facility or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of an instrument may utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. The use of such techniques and the resulting reconditioned instrument are all within the scope of the present application.

Furthermore, in this disclosure, like-named components of the embodiments generally have similar characteristics, and therefore, in a particular embodiment, each feature of each like-named component will not necessarily be described in full detail. Additionally, to the extent that linear or circular dimensions are used in describing the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that may be used in conjunction with such systems, devices, and methods. Those skilled in the art will recognize that equivalent dimensions for such linear and circular dimensions can be readily determined for any geometric shape. The size and shape of the systems and devices, and their components, may depend, at least, on the anatomical structure of the subject within which the systems and devices are used, the size and shape of the components with which the systems and devices are used, and the method and procedure in which the systems and devices are used.

It will be appreciated that the terms "proximal" and "distal" are used herein with reference to a user, such as a clinician, holding the handle of the instrument. Other spatial terms, such as "forward" and "rearward," similarly correspond to distal and proximal, respectively. It will be further appreciated that for convenience and clarity of illustration, spatial terms, such as "vertical" and "horizontal," are used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these spatial terms are not intended to be limiting and absolute.

Values or ranges can be expressed herein as "about" and/or "approximately" from one particular value to another particular value. When values or ranges are expressed in this manner, other disclosed embodiments include the recited particular value and/or from the one particular value to the other particular value. Similarly, when values are expressed in an approximation format by use of the antecedent "about," it will be understood that a number of disclosed values are recited and that the particular values form another embodiment. It will be further understood that there are a number of disclosed values, and that each value is herein disclosed as being "about" in addition to the particular value itself. In some embodiments, "about" can be used to mean, for example, within 10% of the recited value, within 5% of the recited value, or within 2% of the recited value.

For purposes of describing and defining the present teachings, unless otherwise noted, it is noted that the term "substantially" is utilized herein to represent the degree of inherent uncertainty that may result from any quantitative comparison, value, measurement, or other representation. The term "substantially" is also utilized herein to represent the degree to which a quantitative representation may vary from the stated standard without resulting in a change in the basic functionality of the object in question.

A person skilled in the art will recognize further features and advantages of the present invention based on the embodiments described above. Thus, the present invention is not to be limited by what has been specifically shown and described, except as indicated by the appended claims. All publications and documents cited herein are expressly incorporated herein in their entirety. Any patents, publications or information that are incorporated herein by reference in whole or in part are only to the extent that the incorporated material does not conflict with existing definitions, descriptions, or other disclosed material set forth in this document. Thus, the disclosures expressly set forth herein shall take precedence over any conflicting documents incorporated herein.

[Embodiment]
(1) A surgical end effector for use with a surgical stapler, comprising:
a cartridge and an anvil movable relative to the cartridge between an open position and a closed position, the cartridge having a plurality of staples disposed therein and a non-planar deck surface facing the anvil, the plurality of staples configured to be deployed into tissue;
a non-fibrous support material formed of at least one fused bioabsorbable polymer and configured to be releasably held on the deck surface so that it can be attached to tissue by the plurality of staples in the cartridge, the support material having a first end and a second end, a longitudinal axis extending between the first end and the second end, the support material comprising:
a first lattice structure extending from a first top surface to a first bottom surface opposite the first top surface, the first bottom surface being complementary to the deck surface and defining at least a portion of a cartridge contact surface of the supplemental material such that the first bottom surface is configured to mate with at least a portion of the deck surface; and a second lattice structure disposed on at least a portion of the first top surface of the first lattice structure, the second lattice structure having an outer top surface at least a portion of which is substantially planar, the second outer top surface defining at least a portion of a tissue contact surface of the supplemental material;
A surgical end effector, wherein the first lattice structure has an uncompressed thickness that varies at least partially transversely to the longitudinal axis of the auxiliary material, thereby creating a consistent tissue gap between the anvil and the auxiliary material when the auxiliary material is releasably held on the cartridge and the anvil is in a closed position with no tissue between the auxiliary material and the anvil, and applying a substantially uniform pressure to the tissue stapled to the auxiliary material for a predetermined period of time when the auxiliary material is in a tissue deployment state.
(2) The surgical end effector of claim 1, wherein at least a portion of the second bottom surface of the second grid is configured to be positioned directly against the deck surface.
(3) The surgical end effector according to claim 1, wherein the first lattice structure includes a plurality of voids aligned with the plurality of staples, such that the first lattice structure does not contribute to the applied stress of the auxiliary material against the tissue stapled to the auxiliary material when in a tissue deployment state.
(4) The surgical end effector according to claim 1, wherein the first lattice structure is formed of a plurality of vertical struts, the plurality of vertical struts extending from the deck surface to the second bottom surface of the second lattice structure when the support material is releasably held on the deck surface.
5. The surgical end effector of claim 1, wherein the second lattice structure comprises a plurality of unit cells, each unit cell being a triplicate periodic minimal surface structure or defined by a plurality of interconnected struts.

(6) The surgical end effector according to claim 5, wherein the triply periodic minimal surface structure is a Schwarz P structure.
7. The surgical end effector of claim 1, wherein the plurality of staples are generally uniform and the second lattice includes a first longitudinal row of first repeating unit cells having a first compression ratio and a second longitudinal row of second repeating unit cells having a second compression ratio greater than the first compression ratio.
8. The surgical end effector of claim 7, wherein each first repeating unit cell has a first wall thickness and each second repeating unit cell has a second wall thickness that is less than the first wall thickness.
9. The surgical end effector of claim 7, wherein the second lattice includes a third longitudinal row of third repeating unit cells each having a third compression ratio greater than the second compression ratio, the second longitudinal row being positioned between the first longitudinal row and the third longitudinal row.
10. The surgical end effector of claim 9, wherein each first repeating unit cell has a first wall thickness, each second repeating unit cell has a second wall thickness less than the first wall thickness, and each third repeating unit cell has a third wall thickness less than the second wall thickness.

11. The surgical end effector of claim 9, wherein the second repeating unit cell and the third repeating unit cell are configured to be positioned relative to the first lattice structure.
(12) A surgical end effector for use with a surgical stapler, comprising:
a cartridge and an anvil movable relative to the cartridge between an open position and a closed position, the cartridge having a deck surface facing the anvil, the deck surface being non-planar;
a first staple row and a second staple row disposed within the cartridge and extending longitudinally along the cartridge, the first staple row having a plurality of first staples having a first undeformed height and the second staple row having a plurality of second staples having a second undeformed height that is greater than the first undeformed height, the first staples and the second staples configured to be deployed into tissue;
a non-fibrous auxiliary material formed of at least one fused bioabsorbable polymer and configured to be releasably held on the deck surface such that it can be attached to tissue by the first plurality of staples and the second plurality of staples in the cartridge, wherein the auxiliary material includes a first longitudinal row of a plurality of first repeating unit cells having a first geometric shape and a second longitudinal row of a plurality of second repeating unit cells having a second geometric shape different from the first geometric shape, such that the geometric shapes of the auxiliary material vary laterally relative to a longitudinal axis of the auxiliary material, thereby creating a consistent tissue gap between the anvil and the auxiliary material when the auxiliary material is releasably held on the cartridge and the anvil is in a closed position without tissue between the auxiliary material and the anvil, and applying a substantially uniform pressure to the tissue stapled to the auxiliary material for a predetermined period of time when the auxiliary material is in a tissue deployment state.
13. The surgical end effector of claim 12, wherein the first repeating unit cells each have a first height and the second repeating unit cells each have a second height greater than the first height.
14. The surgical end effector of claim 12, wherein the first repeating unit cells each have a first wall thickness and the second repeating unit cells each have a second wall thickness greater than the first wall thickness.
15. The surgical end effector of claim 12, wherein each of the first repeating unit cells has a first compression ratio and each of the second repeating unit cells has a second compression ratio less than the first compression ratio.

16. The surgical end effector of claim 12, wherein the support material includes a third longitudinal row of a plurality of third repeating unit cells having a third geometric shape different from the first geometric shape and the second geometric shape.
17. The surgical end effector of claim 16, wherein each of the third repeating unit cells has a third height, the third height being greater than each of a first height of the first repeating unit cell and a second height of the second repeating unit cell.
18. The surgical end effector of claim 16, wherein each of the third repeating unit cells has a third wall thickness, the third wall thickness being greater than each of the first wall thickness of the first repeating unit cell and the second wall thickness of the second repeating unit cell.
19. The surgical end effector of claim 16, wherein each of the first repeating unit cells has a first compression ratio, each of the second repeating unit cells has a second compression ratio less than the first compression ratio, and each of the third repeating unit cells has a third compression ratio less than the second compression ratio.
20. The surgical end effector of claim 12, wherein at least one of the first repeating unit cell and the second repeating unit cell comprises one or more triply periodic minimal surface structures.

21. The surgical end effector of claim 12, wherein at least one of the first repeating unit cell and the second repeating unit cell comprises a Schwarz P structure.
22. The surgical end effector of claim 12, wherein at least one of the first repeating unit cell and the second repeating unit cell comprises a modified Schwarz P structure.

Claims (14)

1. A surgical end effector for use with a surgical stapler, comprising:
a cartridge and an anvil movable relative to the cartridge between an open position and a closed position, the cartridge having a plurality of staples disposed therein and a non-planar deck surface facing the anvil, the plurality of staples configured to be deployed into tissue;
a non-fibrous support material formed of at least one fused bioabsorbable polymer and configured to be releasably held on the non-planar deck surface so that it can be attached to tissue by the plurality of staples in the cartridge, the non-fibrous support material having a first end and a second end, a longitudinal axis extending between the first end and the second end, the non-fibrous support material comprising:
a first lattice structure extending from a first top surface to a first bottom surface opposite the first top surface, the first lattice structure being defined by a plurality of interconnected first struts, or being formed of a plurality of vertical struts spaced apart from one another in a direction transverse to the longitudinal axis of the non-fibrous auxiliary material, or having a sheet diamond structure having diamond minimal surfaces having a triple periodic minimal surface structure, a Schwartzian P structure, a Schwartzian D-plane lattice structure, a gyroid structure, or a cosine structure, the first bottom surface being complementary to the non-planar deck surface and defining at least a portion of a cartridge contact surface of the non-fibrous auxiliary material, such that the first bottom surface is configured to mate with at least a portion of the non-planar deck surface; and a second lattice structure disposed on at least a portion of the first top surface of the first lattice structure, the second lattice structure comprising a plurality of unit cells, each of the plurality of unit cells being defined by a plurality of interconnected second struts, or a sheet diamond structure having diamond minimal surfaces with a triple periodic minimal surface structure, a Schwartzian P structure, a Schwartzian D-plane lattice structure, a gyroid structure, or a cosine structure, the second lattice structure extending from an at least partially planar second outer top surface to a second bottom surface opposite the second outer top surface , the second outer top surface defining at least a portion of the tissue contact surface of the non-fibrous support material;
When the non-fibrous auxiliary material is releasably held on the cartridge and the anvil is in the closed position without tissue between the non-fibrous auxiliary material and the anvil, the non-planar deck surface of the cartridge is gradually tapered in height from a center of the non-planar deck surface toward both ends in the lateral direction, the first bottom surface of the first lattice structure is gradually tapered in height from a center of the first bottom surface toward both ends in the lateral direction, the anvil has a planar tissue compression surface extending between staple pockets, and the second outer upper surface of the second lattice structure is formed of a plurality of planar surfaces and a plurality of concave surfaces alternately arranged in the lateral direction. a first unit cell, a second unit cell, and a third unit cell of the plurality of unit cells of the second lattice structure are sequentially arranged from a central portion toward one end in the lateral direction, the third unit cell having a compression ratio greater than that of the second unit cell, the second unit cell having a compression ratio greater than that of the first unit cell, and the first lattice structure having an uncompressed thickness at a central portion in the lateral direction that is smaller than the uncompressed thickness at both end portions in the lateral direction . The surgical end effector of claim 1 , wherein at least a portion of the second bottom surface of the second lattice structure is configured to be positioned directly against the non-planar deck surface. The surgical end effector of claim 1 , wherein the first lattice structure includes a plurality of voids aligned with the plurality of staples. 2. The surgical end effector of claim 1, wherein the first lattice structure is formed with a plurality of vertical struts, the plurality of vertical struts of the first lattice structure extending from the non- planar deck surface to the second bottom surface of the second lattice structure when the non-fibrous auxiliary material is releasably held on the non -planar deck surface. The surgical end effector of claim 1 , wherein a wall thickness of the third unit cell is less than a wall thickness of the second unit cell, and the wall thickness of the second unit cell is less than a wall thickness of the first unit cell . 1. A surgical end effector for use with a surgical stapler, comprising:
a cartridge and an anvil movable relative to the cartridge between an open position and a closed position, the cartridge having a deck surface facing the anvil, the deck surface being non-planar;
a first staple row and a second staple row disposed within the cartridge and extending longitudinally along the cartridge, the first staple row having a plurality of first staples having a first undeformed height and the second staple row having a plurality of second staples having a second undeformed height that is greater than the first undeformed height, the first staples and the second staples configured to be deployed into tissue;
a non-fibrous support material formed of at least one fused bioabsorbable polymer and configured to be releasably held on the deck surface such that it can be attached to tissue by the first plurality of staples and the second plurality of staples in the cartridge, the non- fibrous support material including a first longitudinal row of a plurality of first repeating unit cells having a first geometric shape and a second longitudinal row of a plurality of second repeating unit cells having a second geometric shape different from the first geometric shape, such that the geometric shape of the non-fibrous support material varies transversely to a longitudinal axis of the non-fibrous support material;
When the non-fibrous auxiliary material is releasably held on the cartridge and the anvil is in the closed position without tissue between the non-fibrous auxiliary material and the anvil, the deck surface of the cartridge gradually decreases in height from the center of the deck surface toward both ends in the lateral direction, the bottom surface of the non-fibrous auxiliary material gradually decreases in height from the center toward both ends in the lateral direction, the anvil has a planar tissue compression surface extending between the staple pockets, the upper surface of the non-fibrous auxiliary material is composed of a plurality of planes and a plurality of concave surfaces alternately arranged in the lateral direction, and the vertical distance between each of the plurality of planes on the upper surface and the tissue compression surface is the first longitudinal row of the plurality of first repeating unit cells are identical, the first longitudinal row of the plurality of second repeating unit cells is disposed closer to a center in the lateral direction than the second longitudinal row of the plurality of second repeating unit cells, the second longitudinal row of the plurality of second repeating unit cells is disposed closer to an end in the lateral direction than the first longitudinal row of the plurality of first repeating unit cells, a first compression ratio of each of the plurality of first repeating unit cells is greater than a second compression ratio of each of the plurality of second repeating unit cells, and a first length of each of the plurality of first repeating unit cells is smaller than a second length of each of the plurality of second repeating unit cells in the vertical direction. The surgical end effector of claim 6 , wherein the plurality of first repeating unit cells each have a first wall thickness and the plurality of second repeating unit cells each have a second wall thickness greater than the first wall thickness. 7. The surgical end effector of claim 6, wherein the non-fibrous auxiliary material includes a third longitudinal row of a plurality of third repeating unit cells having a third geometric shape different from the first geometric shape and the second geometric shape, and the third longitudinal row of the plurality of third repeating unit cells is disposed toward the end in the lateral direction relative to the second longitudinal row of the plurality of second repeating unit cells . 9. The surgical end effector of claim 8, wherein each of the third repeating unit cells has a third length in the vertical direction , the third length being greater than each of a first length of the first repeating unit cell and a second length of the second repeating unit cell. 9. The surgical end effector of claim 8, wherein each of the third repeating unit cells has a third wall thickness, the third wall thickness being greater than each of the first wall thickness of the first repeating unit cell and the second wall thickness of the second repeating unit cell. The surgical end effector of claim 8 , wherein the third repeating unit cells each have a third compression ratio less than the second compression ratio. The surgical end effector of claim 6 , wherein at least one of the first repeating unit cell and the second repeating unit cell comprises one or more triply periodic minimal surface structures. The surgical end effector of claim 6 , wherein at least one of the first repeating unit cell and the second repeating unit cell comprises a Schwarz P structure. The surgical end effector of claim 6 , wherein at least one of the first repeating unit cell and the second repeating unit cell comprises a modified Schwartz P structure.

Images