JP2004508888A - Bone formation fusion device - Google Patents

Abstract

An intervertebral bone formation fusion device 10 is provided comprising opposing end pieces 11, 12 having an integral central element 13. The end pieces are dimensioned to maintain the height of the disc space. The central element has a much smaller diameter, so that the osteogenic fusion device forms an annular cavity around the central element. An osteogenic material is located in the annular cavity 24 between the opposing end pieces. In one embodiment, the osteogenic material comprises a collagen sheet 30 immersed in a solution that retains the bone morphogenic protein. The osteogenic fusion device is configured such that the osteogenic material is in direct contact with adjacent vertebrae.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to implants that remain in the intervertebral space after removal of the damaged disc. In particular, the present invention relates to an osteogenic fusion device that promotes arthrodesis or fusion between adjacent vertebrae while maintaining a normal spinal anatomy at the location of the vertebrae where the implant is mounted.
[0002]
In many cases, back pain is caused by damage or loss of the disc between adjacent vertebrae. Discs can become herniated or be affected by a wide variety of degenerative conditions. In many cases, these diseases affecting the disc can impair the normal anatomical function of the disc. In some cases, this deficiency is significant enough to require surgical intervention.
[0003]
In one such surgical procedure, the affected disc is substantially removed and the adjacent vertebrae fused together. In this treatment, discectomy is performed to remove the disc nucleus while retaining the annulus. As the intervertebral disc material is removed, objects must be placed in the intervertebral space to prevent the intervertebral space from collapsing.
[0004]
In early spinal fusion techniques, bone material or osteogenic fusion devices were typically simply placed between adjacent vertebrae on the posterior aspect of the vertebrae. In the early history of these osteogenic fusion devices, the osteogenic fusion device was formed of cortical-cancellous bone that was not strong enough to support the weight of the spine at the location where the implant was mounted. Therefore, the spine was stabilized by a plate or rod across the affected vertebra. In the case of this technique, if fusion occurs across the osteogenic fusion device and involves the osteogenic fusion device, the object used to maintain spinal column stability will be in the way.
[0005]
Following the success of the early fusion techniques, emphasis was placed on modifying the devices to be placed in the disc space. Later, attention was focused on implants, ie, fusion devices between vertebral bodies, which could be interposed between adjacent vertebrae, preserving the stability of the disc space, while still allowing fusion or arthrodesis. These intervertebral body fusion devices take many forms. For example, one common form is a cylindrical hollow implant or “cage”. The outer wall of the cage forms an interior space within the cylindrical implant, which is filled with, for example, bone chips or other bone growth inducing material. This type of implant is disclosed in US Pat. No. 4,501,269 to Bagby, US Pat. No. 4,878,915 to Brantigan, US Pat. No. 4,961, to Ray. 740 and Michelson U.S. Pat. No. 5,015,247 are representative. In some cases, the cylindrical implant had a threaded exterior to allow for threaded insertion into a tapped hole formed in an adjacent vertebra. Alternatively, some fusion implants are designed to penetrate into the intervertebral space.
[0006]
The past several years of experience with these intervertebral fusion devices have demonstrated the effectiveness of these implants in achieving solid fusion. Changes in implant design were considered with respect to improvements in stabilizing the motion segment during fusion. However, some intervertebral fusion devices have still been difficult to achieve complete fusion, at least without the aid of some additional stabilizing devices such as rods or plates. . Furthermore, some of these devices are not structurally strong enough to support the heavy loads and bending moments applied at certain locations in the spine, ie, within the lumbar spine.
[0007]
Even without these difficulties, there are other undesirable features. Recent studies have shown that the intervertebral body fusion implant device, ie, the cage, as often referred to, produces a bone stress shielding effect within the cage. It is well known that the application of stress or load to bone material promotes bone growth. The stress shielding phenomenon will remove some or all of the load applied to the material to be fused, which significantly increases the time required for the bone to fully grow, or ultimately The quality and density of the formed fusion mass may be impaired. In some cases, the stress shielding effect may cause bone chips or fusion masses retained within the fusion cage to resorb or grow into fibrous tissue instead of within the bone fusion mass. is there.
[0008]
A further difficulty found with many fusion implants is that the implant material is not radiopaque. Most fusion cages are made of a metal, such as stainless steel, titanium or porous tantalum. Cage metal is clearly visible on all radiographs (X-rays) or CT scans. Since most fusion devices completely surround and retain the bone graft material contained within the cage, the fusion mass growing in the metal cage between adjacent vertebrae is not compatible with conventional radiographic imaging techniques. Cannot be visualized, and can be visually recognized only by using an image scanner by CT scan. Thus, the spine surgeon has no means to determine the progress of the fusion and, in some cases, cannot confirm whether the fusion is complete and successful.
[0009]
For the field of spinal fusion, it would be beneficial to have an intervertebral fusion device that could support bone growth material in the intervertebral space while maintaining the normal height of the disc space. The device eliminates the risk of stress shielding effects of the fusion mass and also allows the fusion mass to be visualized as the arthrodesis progresses.
[0010]
Summary of the Invention
In order to address the current challenges with intervertebral fusion devices, the present invention provides an osteogenic fusion configured to place as much bone growth inducing material as possible in direct contact with adjacent bone. Think of it as a device. In one embodiment, an osteogenic fusion device includes an elongate body having opposing first and second end pieces separated by an integral central element. The central element has a diameter that is significantly smaller than the two end pieces. In this way, the osteogenic fusion device forms an annular cavity between the end pieces and around the central element.
[0011]
According to one aspect of the invention, the bone growth inducing material is disposed in an annular cavity around a central element of the osteogenic fusion device. In one particular embodiment, the bone growth inducing material comprises a sheet of a carrier that is pharmaceutically suitable for bone growth factors, such as bone morphogenic proteins. In this embodiment, the sheet can be a collagen sheet in which the BMP is soaked and then wrapped in a helical fusion around the central element of the osteogenic fusion device.
[0012]
In one aspect of the invention, the osteogenic fusion device can be implanted in a bilateral approach. Specifically, after completing the discectomy, two such osteogenic fusion devices can be inserted into the prepared holes in the endplates of adjacent vertebrae. The spinal load is supported by two end plates in direct contact with adjacent vertebral bodies. Preferably, the osteogenic fusion device should have at least a portion of the end pieces at the epiphyses of adjacent vertebrae long enough to allow contact with harder bone. Thus, when the osteogenic fusion device is inserted, the bone growth inducing material comes into direct contact with the adjacent vertebral bodies. Further, the bone growth inducing material can be located in both lateral spaces separating the two osteogenic fusion devices. When fusion occurs, a substantial fusion mass is generated that is substantially unhindered by the material of the osteogenic fusion device itself.
[0013]
Several alternative embodiments of the osteogenic fusion device are provided, all of which maintain the ability to support the bone growth inducing material in direct contact with adjacent vertebrae. It is. In some embodiments, additional elements of the central element are provided, while in other embodiments, an intermediate piece is provided for further support across the disc space. In one embodiment, an osteogenic fusion device is provided wherein at least one of the opposing end pieces has a truncated surface. In yet another embodiment, the truncated surface preferably has an opposing surface, such as an opposing edge, defining an entrance to the notch area. The notch area is typically defined by a truncated surface, and the truncated surface is preferably concave. Such an implant is preferably configured to nest within another fusion device, such as the fusion device of the present invention.
[0014]
Another embodiment of the present invention comprises at least two load bearing members, as described above, adapted to be positioned bilaterally between adjacent vertebrae, wherein at least one of the load bearing members has the other load bearing member. An implant system having a truncated surface configured to nest within a bearing member is provided.
[0015]
Yet another embodiment of the present invention includes at least first and second load bearing members adapted to be bilaterally disposed between adjacent vertebrae, and wherein the load bearing members are lateral. An implant system for promoting fusion bone growth in adjacent intervertebral spaces connected to one another so as to resist directional separation. In particular, one preferred embodiment provides a first member of the load bearing member having a male member and a second member of the load bearing member having a female member. The male and female members cooperate to resist lateral separation of the device. In another preferred embodiment, the load bearing members can be connected by a connecting member such as a plate straddling the two load bearing members.
[0016]
In another embodiment of the present invention, a method is provided for promoting fused bone growth in an adjacent intervertebral space. These methods include providing a load bearing member or implant system as described above, and preparing adjacent vertebrae to receive the load bearing member or implant system within the intervertebral space between adjacent vertebrae. Placing the load bearing member or implant system in the intervertebral space after the preparing step.
[0017]
The present invention also contemplates using an insertion tool and making certain modifications to the osteogenic fusion device to accept the tool. In one preferred embodiment, the tool is essentially an elongate shaft extending the opposite branch. The bifurcation can engage the truncated sidewall of one end piece. Furthermore, notches can be formed in the end pieces to receive the tips of the two branches. This design allows the osteogenic fusion device to be a push-in or screw-type osteogenic fusion device.
[0018]
One object of the present invention is to provide an intervertebral body fusion device that allows as much as possible contact between adjacent vertebrae and the bone growth inducing material supported by the osteogenic fusion device. is there. A further object is to provide an osteogenic fusion device as described above that is capable of supporting the load generated throughout the spine without the growth of stress-shielding bone within the osteogenic fusion device. It is to provide.
[0019]
Another object of the present invention is achieved by an action that minimizes the radiation transmission of the device. As a result, there is an advantage that the surgeon can more easily determine the progress of the fusion of the spine.
[0020]
It is yet another object of the present invention to provide an intervertebral body fusion device in which two large devices are placed side-by-side to provide sufficient lateral exposure to distract the disc space and promote fusion. To provide.
[0021]
Yet another object of the present invention is to provide an intervertebral body fusion device that can be placed closer to another intervertebral body fusion device and that eliminates or minimizes the need to resect a facet joint. It is to be.
[0022]
It is yet another object of the present invention to provide an implant system that is placed in the intervertebral space with minimal retraction of the spinal cord to reduce the potential for neurological complications or damage.
[0023]
Other objects and advantages of the present invention can be understood from the following description and the accompanying drawings.
[0024]
[Description of preferred embodiments]
For the purposes of promoting an understanding of the principles of the invention, embodiments illustrated in the drawings will now be described, and specific terms will be used for the description. However, this is not intended to limit the scope of the invention in any way. Modifications and further modifications of the illustrated apparatus and further applications of the illustrated principles of the invention are not intended to It would normally be devised by one of ordinary skill in the relevant art.
[0025]
The present invention contemplates an osteogenic fusion device used as an intervertebral fusion device. The osteogenic fusion device has opposing end pieces configured to span the disc space and engage adjacent vertebral bodies. The osteogenic fusion device of the present invention has a central element that separates the two end pieces and substantially spans the anterior-posterior length of the disc space. The present invention contemplates placing the bone growth inducing material around the central element and between the opposing end pieces. Once the osteogenic fusion device of the present invention is implanted in a patient, the bone growth inducing material directly contacts adjacent vertebral bodies. The end pieces are made of a material sufficient to resist spinal loads generated at the vertebral location where the implant is mounted.
[0026]
According to one embodiment of the invention, the osteogenic fusion device 10 shown in FIGS. 1 and 1 has a first end piece 11 and a second end piece 12. The end pieces are separated by a central element 13. The first end piece 11 is substantially cylindrical or of any geometric shape and has an outer surface 15 that contacts the bone. End piece 11 also defines an inward facing holding surface 17. The central element 13 extends integrally from the holding surface 17 of the first end piece 11.
[0027]
The second end piece 12 also defines a bone contacting surface 20 that in this embodiment does not extend completely around the end piece. The bone contacting surface 20 can be of any geometric shape, preferably circular, and is defined with a radius equal to the radius of the outer surface 15 of the first end piece. Thus, as illustrated in FIG. 2, the bone contacting surface 20 of the second end piece 12 may have a first bone forming fusion device when viewed along the longitudinal end of the central element 13. It substantially coincides with the portion of the outer surface 15 of the end piece 11. The second end piece 12 also has opposing truncated surfaces 21 located between the circular bone contacting surfaces 20. Preferably, the truncated surface 21 is substantially flat and can be configured to engage a fusion tool. The insertion tool preferably has an arm in contact with the flat truncated surface 21 but still within the envelope defined by the outer surface 15 of the first end piece 11.
[0028]
The second end piece 12 also defines a second holding surface 22 facing the first holding surface 17 of the first end piece 11. Also in this case, it is preferable that the central element 13 is integral with the second holding surface 22 and protrudes outward from the second holding surface 22. Alternatively, the central element may be in the form of a central rod engaged in a co-linear hole formed in the two end pieces. In this variant, the engagement between the central rod and the end pieces can be threaded.
[0029]
The central element 13 has a central outer surface 23. Preferably, the central element 13 is substantially cylindrical along its length. In one aspect of the invention, the first end piece 11 has a diameter D ₁ While the central element 13 has a diameter D ₂ Is defined. Diameter D ₁ Is at least equal to the height of the disc within which the osteogenic fusion device 10 is interposed. Most preferably, the diameter D ₁ Is equal to the diameter of the cylindrical passage cut into the end of the adjacent vertebra. In this case, the diameter D ₁ Is slightly larger than the height of the disc space. Furthermore, the diameter D ₁ Is the diameter D of the central element 13 ₂ Significantly larger than This difference in diameter will form an annular cavity 24 surrounding the central element 13.
[0030]
The osteogenic fusion device 10 has a length L between the opposing ends of the osteogenic fusion device. ₁ have. This length L ₁ Is preferably slightly less than the anterior-posterior length of the disc space, but this length can be calibrated to the lateral dimensions of the disc space. Most preferably, the length L ₁ Is dimensioned such that the first end piece 11 and the second end piece 12 can contact the epiphysis or at least a portion of the harder cortical bone around the circumference of the vertebral endplate. The osteogenic fusion device 10 has a length L which is approximately the length of the central element 13. ₂ Is further defined. Length L ₂ Is calibrated such that the end pieces 11, 12 are wide enough to provide sufficient support between adjacent vertebrae. Conversely, the length L ₂ Is long enough to allow the annular cavity 24 to hold a significant amount of bone growth inducing material.
[0031]
In one variation of the osteogenic fusion device 10, the second end piece may be configured with a thread. For example, as shown in FIG. 3, the end piece 25 has an external thread engagement portion 26 extending from the outer surface 27. According to this embodiment, the second end piece 25 is cylindrical like the first end piece 11 or, like the truncated face 21 in the previous embodiment, between the truncated faces. Can be formed with a threaded portion. In any event, threaded end piece 25 is configured to threadably advance into a pierced and tapped passageway in the adjacent vertebral body. The first end piece 11 can also be threaded to facilitate insertion and reduce the possibility of extrusion.
[0032]
In a further aspect of the invention, a bone growth inducing material 30 is provided to be supported by the osteogenic fusion device 10. Preferably, the material 30 is in the form of a sheet. In certain embodiments, the carrier sheet 30 can be a collagen sheet impregnated with a solution retaining bone growth inducing material or bone morphogenetic protein (BMP). In accordance with the present invention, the carrier sheet 30 can be formed of a wide variety of materials other than collagen, provided that the material can hold a therapeutically effective amount of a bone growth inducing material or BMP. Further, the material 30, whether in sheet form or not, is most preferably handleable so that it can be placed within the annular cavity 24 of the fusion device 10.
[0033]
According to a particular embodiment, the carrier sheet 30 is wrapped around the outer surface 23 of the central element 13 (see FIG. 5). The carrier sheet 30 is held between the holding surface 17 of the first end piece 11 and the holding surface 22 of the second end piece 12. According to one particular embodiment, the retaining surface 22 is curved or convex. In this way, the carrier sheet 30 can be made to protrude so as to function as a kind of anchor that holds the carrier sheet 30 in the annular cavity 24 of the osteogenic fusion device 10. In addition, the convex surface 22 better matches the anterior portion of the vertebral body profile when the fusion device is implanted.
[0034]
In the illustrated embodiment, the carrier sheet 30 can be provided as a single sheet, as shown in FIG. The inner end 31 of the sheet is arranged against the central outer surface 23 of the central element 13. The sheet can be spirally wound around the central element 13 until its outer end 32 is positioned adjacent the outer surface 15 of the first end piece 11. The carrier sheet 30 has a length L between the first end piece and the second end piece. ₂ It has a width W, which is preferably slightly wider than it, so that a part of the carrier sheet 30 projects into the concave holding surface 22 of the second end piece 12. The total length of the sheet 30 between the ends 31, 32 is its thickness and diameter D ₁ , D ₂ It depends on the difference. For example, in one embodiment, the diameter D ₂ Is the diameter D ₁ Is about 1/4. Preferably, this length is sufficient to tightly wind the carrier sheet 30 around the central element 13 and fill the annular cavity 24. One important object of the present invention is to ensure that the carrier sheet 30 or bone growth inducing material is in direct contact with adjacent vertebrae. As a result, the sheet 30 preferably has its outer edge 32 at least slightly outside the envelope of the outer surface 15 of the first end piece 11.
[0035]
The carrier sheet 30 of FIGS. 4-6 illustrates one particular embodiment of a bone growth inducing material that can be used with the osteogenic fusion device of the present invention. It is also contemplated that the carrier can be in the form of a sponge, paste, gel, or a hardenable bone-forming material. The osteogenic material must be provided in some form that can be substantially retained around the central element 13 and within the annular cavity 24 of the osteogenic fusion device 10. In other words, the present invention contemplates an osteogenic material that does not need to be held in a conventional manner in a prior art hollow cylindrical cage. In these prior art devices, spongy bone chips were retained in hollow cages. In one preferred form, if the paste or gel has sufficient density to retain the bone growth inducing material on and within the osteogenic fusion device 10, the bone chips retained within the bone paste or gel are removed. It can be used with the osteogenic fusion device 10.
[0036]
According to one particular embodiment, the end pieces 11, 12 are solid and circular in shape. Alternative end piece configurations are illustrated in FIGS. For example, the end piece 11 'may have a plurality of substantially circular openings 34 circumferentially disposed around the end piece, as shown in FIG. The end piece 11 '' shown in FIG. 8 has a plurality of pie-shaped openings 35, so that the end piece shows the appearance of a wheel with spokes. The second end piece 12 of the osteogenic fusion device 10 can have a similar opening defined therethrough. Openings 34, 35 in end pieces 11 ', 11 "provide additional passages that promote fused bone growth. The openings themselves can be filled with an osteogenic material such as a gel or paste. Further, once the osteogenic fusion device 10 is implanted within the disc space, the osteogenic material can be consolidated around the osteogenic fusion device within the disc space. These additional openings in the end pieces 11, 12 provide additional passages for forming a bone bridge between adjacent vertebrae. In addition, these and other openings may allow the implant to be injected, for example, by injecting osteogenic material through the openings in an amount sufficient to fill a void formed between the implant and its surrounding environment. Once in place, it can be used as an inlet for inserting osteogenic material into the site of the implant.
[0037]
End pieces 11, 12 etc. can also be non-circular in shape. For example, the end pieces may be rectangular or other polyhedral shapes. If the osteogenic fusion device is in a passage prepared in the end plate, the shape of the passage can be modified to fit the bone engaging surfaces 15, 20 of the end pieces.
[0038]
9 to 11 show adjacent vertebral bodies V ₁ , V ₂ A pair of osteogenic fusion devices 10 are shown implanted in a bilateral configuration therebetween. As shown, the annular disc A is retained, but must define at least one portal in the annular disc A to allow insertion of the osteogenic fusion device 10. The present invention also contemplates inserting each of the osteogenic fusion devices 10 through its own portal formed in the annular disc A. Alternatively, in accordance with other known methods, a single portal may be provided through which each osteogenic fusion device 10 may be conveniently inserted. Further, in accordance with the present invention, the osteogenic fusion device 10 can be placed in the disc space according to known posterior or posterior lateral insertion techniques.
[0039]
According to the invention, the osteogenic fusion device 10 is inserted into the intervertebral disc space S so that the first end piece 11 is first advanced into the disc space. Preferably, the passage C is drilled into the vertebral endplate E to one preferred insertion depth of the osteogenic fusion device 10 according to known techniques. If the implanted osteogenic fusion device is of the type shown in FIG. 3 having a threaded second end piece 25, the passage C is suitably drilled to accept the bone engaging screw 26. And tapping is possible. In one variation of this configuration, the first end piece 11 can also hold an external thread.
[0040]
The preferred embodiment also contemplates a substantially cylindrical osteogenic fusion device positioned within a circular passage. Alternatively, the osteogenic fusion device may function as a separator that directly contacts the endplate without preparing a passageway. In this case, the bone engaging surface of the end piece can be modified to match the geometry of the vertebral endplate.
[0041]
As shown in FIGS. 9-11, the osteogenic material 30 is placed in direct contact with the adjacent vertebral endplate E. Further, positioning the osteogenic fusion device 10 can provide an intermediate space 37 between the two osteogenic fusion devices. The osteogenic material can then be placed in the intermediate space 37, also in direct contact with the osteogenic material 30 located around each central element 13 of the osteogenic fusion device 10. Once complete fusion has occurred, new bone growth is replaced by the carrier material 30 and the adjacent vertebra V ₁ , V ₂ To form a solid bone bridge over the bridge. As can be seen from FIGS. 9-11, the continuous area of bone growth is quite pronounced and is not interrupted by the structure of the fusion device itself.
[0042]
Of course, it will be appreciated that the end pieces 11, 12 provide sufficient support for vertebral loads passing between adjacent vertebrae. At the same time, this load bearing capacity is concentrated outside the intermediate region of the vertebral endplate E. The central region of the endplates is extremely heavily blood-flowed and has a large capacity for new bone growth. Thus, the elimination of the structural material of the osteogenic fusion device 10 from that area allows for faster and more complete arthrodesis to be achieved than is possible with prior art fusion cages.
[0043]
14 and 15, there is shown an insertion tool 50 for inserting the osteogenic fusion device 10 according to the present invention. The insertion tool 50 has a solid shaft 51 to which a knob or handle 52 is fixed. Knob 52 is configured to be grasped and manipulated by hand during insertion of the osteogenic fusion device. If the osteogenic fusion device is not threaded, the insertion tool 50 simply functions as a pushing device. On the other hand, if the osteogenic fusion device has threaded end pieces as shown in FIG. 3, the insertion tool 50 must be turned when screwing the end pieces into the passages provided between adjacent end plates. No.
[0044]
The insertion tool 50 has a pair of bifurcated portions 53 that are separated so as to define a recess 54 in the end piece. For insertion of the osteogenic fusion device 10 shown in FIG. 1, the recess 54 of the end piece is configured such that the branch portion 53 is in close contact with the truncated surface 21 of the second end piece 12. The outer surface of the bifurcation 53 can conform to a portion of the outer surface 15 of the first end piece 11.
[0045]
The insertion tool 50 illustrated in FIGS. 14 and 15 also has a tapered tip 55 at each end of the bifurcation 53. These tapered tips 55 are configured to be receivable within the drive notch 41 of the first modified end piece 40 shown in FIGS. The osteogenic fusion device shown in FIGS. 12 and 13 is substantially similar to the osteogenic fusion device 10 shown in FIG. 1 except that a drive notch has been added. The insertion tool 50 is configured such that the tip 55 protrudes into the notch 41, while the branch portion 53 directly contacts the truncated surface 21 of the second end piece 12. This particular embodiment of the insertion tool is particularly useful for screwing an osteogenic fusion device. Preferably, the branch portion 53 has a diameter D ₁ Has an effective outer diameter approximately equal to Further, the branch portion 53 may have the form of an arcuate segment that is complementary to the truncated surface 21. If the end piece 12 is threaded (see FIG. 3), the branch portion 53 can have complementary threads along its length.
[0046]
The present invention also contemplates an osteogenic fusion device that restores the normal lordotic angle of the intervertebral segment. Specifically, the lordosis fusion device 60 has a first end piece 61 and a second end piece 62 as shown in FIG. As in the previous embodiment, a central element 63 is provided for connecting the two end pieces. The outer surface 65 of the first end piece 61 is in the form of a frustoconical surface. Outer surface 65 tapers toward second end piece 62 at a preferred lordosis angle. Similarly, the outer surface 66 of the second end piece 62 is tapered with a similar lordosis angle. Alternatively, the second end piece 62 can have a thread formed on the outer surface 66. The threads 66 on the smaller second end piece 62 cannot contact the vertebral endplate at the larger insertion end, but the threads contact the endplate at the anterior end of the intervertebral disc space and lordosis. It functions as an anchor that resists extrusion of the osteogenic fusion device 60.
[0047]
The present invention contemplates making some modifications to the basic osteogenic fusion device 10. For example, the osteogenic fusion device 70 illustrated in FIG. 17 has a first end piece 71, a second end piece 72, and a central piece 73 disposed between the two end pieces. ing. First and second central elements 74, 75 connect each of the end pieces 71, 72 to the central piece 73. In this case, the central piece 73 contacts the inside of the disc end plate E. Until the bone growth inducing material is exposed on the outer surface of the osteogenic fusion device 70, an osteogenic material, such as the carrier sheet 30, can be placed and wound around each of the central elements 74,75.
[0048]
In a further variation, the osteogenic fusion device 80 illustrated in FIG. 18 has a first end piece 81 and a second end piece 82 connected by a plurality of central beams 83. In the illustrated embodiment shown in FIG. 19, four such beams 83 are provided. However, other arrangements and numbers of beams are conceivable. Supporting the osteogenic material by a number of beams 83 between the first end piece 81 and the second end piece 82 so that the bone growth inducing material is in direct contact with the adjacent vertebral body Thus, an important feature of the present invention is retained by the osteogenic fusion device 80.
[0049]
The two embodiments of FIGS. 20 and 21, 22 and 23 differ slightly from the general concept of the osteogenic fusion device 10. In these two embodiments, the small diameter central element 13 has been replaced by a wall. In the embodiment of FIGS. 20 and 21, the osteogenic fusion device 85 has a first end 86 and a second end 87 separated by a central element 88. First end 86 and second end 87 may be in the form of a short cylindrical portion, such as first end piece 11 of osteogenic fusion device 10 of FIG. Although the central element 88 may be in the form of an uncut wall, the osteogenic fusion device 85 preferably has a number of openings or slots 89 formed in the central element 88. According to a particular embodiment, the slots extend along substantially the entire length of the central element 88. Although the osteogenic fusion device 85 differs somewhat from the concept of the osteogenic fusion device 10, this latter osteogenic fusion device 85 retains the broad beneficial features of the present invention, namely, the osteogenic fusion device. There is direct contact between the osteogenic material supported by 85 and the disc. In that case, the osteogenic fusion material can be placed on both sides of the central element 88. Further, material can be passed through the slot 89.
[0050]
Preferably, the osteogenic fusion device 85 is oriented within the disc space such that the central element 88, ie, the wall, straddles between adjacent vertebrae. This central element 88, in turn, provides additional structure and load bearing capacity to support the spine load at the location where the implant is mounted.
[0051]
The osteogenic fusion device 90 of FIGS. 22 and 23 operates based on the same concept as the osteogenic fusion device 85. However, in this case, the first and second end pieces are in the form of arc segments rather than short cylinders. Specifically, the osteogenic fusion device 90 includes an upper and lower first arcuate segment 91. _U , 91 _L And upper and lower second arcuate segments 92 _U , 92 _L And The osteogenic fusion device 90 also has a central element 93, also in the form of a wall connecting the first end piece and the second end piece. As can best be seen from FIG. 23, the arcuate segments 91, 92 and the central element 93 define a pair of cavities for holding osteogenic material. In this embodiment, the osteogenic material can be completely contained from end to end of the osteogenic fusion device 90. In the previous embodiment, the osteogenic material is encapsulated in the holding surfaces of the opposing end pieces. According to certain embodiments, the osteogenic fusion device 90 includes upper and lower, first and second arcuate segments 91. _U , 91 _L , 92 _U , 92 _L Have a plurality of openings 94 defined therein. Similarly, a plurality of openings 95 can be defined in the central element 93. In this way, the aperture provides the greatest potential for bone ingrowth through the osteogenic fusion device, as well as around the osteogenic fusion device 90.
[0052]
The osteogenic fusion device 100 illustrated in FIGS. 24 and 25 similarly provides a slightly different idea. The osteogenic fusion device 100 includes a first end piece 101, a second end piece 102, and a central element 103 that are similar to similarly named components of the osteogenic fusion device 10. I have. However, the osteogenic fusion device 100 also has a side piece 104 that spans between the first end piece 101 and the second end piece 102. Furthermore, unlike the osteogenic fusion device 10, the first and second end pieces 101, 102 are not generally circular in shape, but are generally rectangular in shape. In one particular embodiment, the end pieces 101, 102 have notches 105 on both sides of the end pieces to provide additional passages for forming a bone bridge between adjacent vertebrae. be able to. As in the previous embodiment, the osteogenic fusion device 100 provides a means for fully confining the osteogenic material, such as in the form of a carrier sheet 30. In this embodiment, the carrier sheet 30 can be wrapped around the central element 103 in the manner described above. This particular embodiment of the invention, the osteogenic fusion device 100, is adapted for use in the lumbar spine as shown in FIG. 26 and in the cervical spine as shown in FIG. It is preferable that the size is set according to the size.
[0053]
In many situations, it is preferable to use two fusion devices in the posterior lumbar vertebral interbody fusion technique (PLIF), but sufficient lateral exposure is obtained to place the two devices side by side. Absent. This problem can be visually grasped by referring to FIG. 28, for example. Two osteogenic fusion devices, such as the osteogenic fusion device 10, can be placed side by side in the surgical window shown in dashed lines. As illustrated in FIG. 28, the two devices do not fit within the provided surgical window. In many such cases, the facet joints must be removed to make the surgical window larger, which can destabilize the spine.
[0054]
To address this problem, at least one end piece of the osteogenic fusion device may have a truncated surface, such as a circular notch, as shown in FIG. As shown in FIG. 29, the two fusion devices thus positioned with respect to each other are telescopically fitted or plugged into each other and are located within the surgical window, so that during insertion of the device from behind, The resection of the small facet joints is not required, or the resection is minimal.
[0055]
As shown more fully in FIGS. 30 and 32, the osteogenic fusion device 110 is similar in many respects to the osteogenic fusion device 10 shown in FIGS. It has opposing end pieces, including a piece 111 and a second end piece 112, and a central element 113. Each of the end pieces defines two opposing surfaces as described for osteogenic fusion device 10 as well. For example, the first end piece 111 defines a bone contacting surface 114 and the second end piece 112 defines a bone contacting surface 115. The bone contacting surface 115 does not extend completely around the end piece 112 in this embodiment. Furthermore, the bone contacting surface of the second end piece 112 generally corresponds substantially to the portion of the outer surface 114 of the first end piece 111 when viewing the device along its central element 13 longitudinal axis. The second end piece 112 also has two opposing truncated surfaces 117 located between the bone contacting surfaces 115. Further, the first end piece 111 has an outer surface 118 and an inner surface 119, while the second end piece 112 has an outer surface 120 and an inner surface 121. The osteogenic fusion device 110 is configured to nest with other osteogenic fusion devices, including other devices of the present invention. In the embodiment illustrated in FIGS. 30-32, the configuration of the osteogenic fusion device 110 has a first end with an opposing surface 123 having opposing edges 123 that define an entrance 124 to the notch region 122. Includes a piece 111. Notch region 122 is defined by truncated surface 116. The truncated surface 116 is concave in this embodiment. As best shown in FIG. 31, the first end piece 111 has a maximum vertical dimension D between two opposing surfaces 114. ₄ Minimum transverse dimension D perpendicular to ₃ have. In the illustrated device, the maximum vertical dimension D ₄ Is the minimum lateral dimension D as a whole ₃ Greater than. Vertical dimension D ₄ Have a height that approximates the desired degree of separation of adjacent vertebrae.
[0056]
FIG. 33 shows that the load bearing member 130 has a first end piece 131 whose truncated surface can be telescopically fitted, and a substantially cylindrical second end piece having no cutout area. 132 is shown.
[0057]
The osteogenic fusion device described above, which is configured to nest, may be modified in a manner similar to that shown in FIGS. 3-13 and 16-21 and its accompanying drawings in the above description. it can. For example, an osteogenic fusion device having a threaded end piece and an end piece having an opening, and a device having a central piece, a plurality of central elements, and a central element defining a wall are shown in FIGS. It can be incorporated into an osteogenic fusion device such as that described with respect to FIG. In devices having a central piece, the central piece may be substantially cylindrical with no notched areas, or as described above, may be shaped with a notched area. In addition, the device can include the bone growth inducing material described above, which can be wrapped around the central element of the device and, if desired, shaped to allow or facilitate a nested configuration. .
[0058]
It will be appreciated that the shape of the opposing end pieces of the load bearing member described above is preferably cylindrical and may include a concave truncated surface. However, opposing end pieces and truncated surfaces having any suitable geometry are considered to form part of the invention.
[0059]
The present invention also provides an implant system having at least two load bearing members as described above, wherein at least one of the load bearing members is configured to nest within the other load bearing member. Also think. FIGS. 34-36 illustrate one embodiment of an implant system having a load bearing member 110 having a generally cylindrical first end piece 11 and a load bearing member 10 (shown in FIGS. 1 and 2). Is illustrated. The first end piece 11 of the load bearing member 10 is telescopically fitted within the first end piece 111 of the load bearing member 110. 36, the width w1 of the second end piece 112 of the load bearing member 110 and the width w1 of the second end piece 12 of the load bearing member 10 are best illustrated in FIG. ₂ Does not prevent the first end piece 11 of the load bearing member 10 from telescopically fitting into the first end piece 111 of the first load bearing member 110 when mated together. No.
[0060]
In a further embodiment, the load bearing members of the telescoping implant system can be of the same shape. For example, FIG. 37 shows two load bearing members in which the first end piece 111 of one of the load bearing members is telescopically fitted within the same end piece 111 of the other load bearing member 110. A perspective view of 110 is shown.
[0061]
FIG. 38 illustrates an implant system 150 of the present invention having a load bearing member 160 and a load bearing member 170. The load bearing member 160 has a second end piece 162 of the load bearing member 160 that is substantially cylindrical and has a notch (ie, has the shape of the first end piece 131 of the load bearing member 130). Except for this point, it is the same as the load bearing member 130. The load bearing member 170 is similar to the load bearing member 130 except that the first end piece 171 of the load bearing member 170 is substantially cylindrical without a notched area. FIG. 38 shows a first end piece 171 of the load bearing member 170 nested within a first end piece 161 of the load bearing member 160 and a second end piece of the load bearing member 160. Also shown is the second end piece 172 of the load bearing member 170 telescoping within 162.
[0062]
The implant system has first and second load bearing members, and the end pieces can be arranged in a variety of ways to achieve a nested configuration. You should understand. For example, the first and second load bearing members can each have one truncated end piece and one non-truncated end piece as shown in FIG. In one such embodiment, the two devices can be used in an inverse relationship to each other so that a nested relationship can be achieved. For example, in the implant system 180 illustrated in FIG. 39, the first end piece 191 of the first load bearing member 190 and the second end piece 202 of the second load bearing member 200 are truncated. ing. The non-truncated first end piece 201 of the load bearing member 200 nests within the first end piece 191 of the load bearing member 190 and the non-truncated second end piece of the load bearing member 190. End piece 192 telescopically fits within second end piece 202 of second load bearing member 200.
[0063]
Referring now to FIGS. 40-42, there is illustrated an implant system of the present invention including a mating fusion device, wherein the devices are connectable to one another such that the devices can resist lateral separation. It is a form. In a preferred system, such a connection increases the resistance to extrusion due to the cooperation of the two devices. In particular, the system 210 has a first fusion device 211 and a second fusion device 212. The first fusion device 211 includes an end piece 215 having an opening 214 functioning as a female member. The second fusion device 212 includes an end piece 210 having a mating member 216 that is appropriately dimensioned to fit within the opening 214 of the device 212 and that functions as a male member. In this manner, when the devices 211, 212 are assembled as shown in FIG. 40, the two devices are connectably mated, separate laterally from each other and / or resist extrusion, and provide a It is desirable to function as a single device when implanted in the body. In this regard, devices 211, 212 can be mated and implanted as a single device prior to implantation, but, for example, first implanting a device such as device 211 and then, for example, first implanting a device such as device 211. And mating member 216 is received in opening 214, thereby connecting the two devices to each other, such as 212, by pushing or sliding along the longitudinal axis adjacent to the device embedded in the second device. It may be preferable to implant the device. As shown, the devices 211, 212 are also configured to nest so as to provide a reduced lateral profile, as described generally above for the particular device. Thus, the device 212 has a concave shoulder portion 217 with a mating member 216 disposed therebetween, with its outer end 218 extending radially outward to a distance that allows a telescoping relationship. In device 212, outer end 218 does not extend further radially outward beyond the dominant cylindrically shaped radius r of end piece 215. The devices 211, 212 can optionally include an outer surface configured to resist extrusion from an adjacent intervertebral space, such as, for example, a screw, ratchet, groove, or other similar working portion. In one form, one of the fusion devices can include threads to facilitate controlled insertion, and the device can be implanted first. Other fusion devices of the system can be push-type, without push-action elements or action elements commonly used in push-type devices such as, for example, a ratchet, similar protrusion, or groove. Further, at least one of the fusion devices can have a stop member that controllably stops insertion of the second device upon contact of the two devices. For example, FIG. 43 shows the mating member of device 212, for example, by first embedding device 220 with first end piece 222 in the distal direction, and then pushing and mating device 212 with device 220. A device 220 is shown, similar to device 211, except that 216 has a stop member 221 arranged to be accessible.
[0064]
44, there is illustrated another implant system of the present invention in which two adjacent fusion devices are connected to each other. In particular, the system 230 includes the first fusion device 10 and the second fusion device 110 as described above. Further, the system 230 has a relatively thin connecting plate 231 that straddles the end pieces of the devices 10,110. For example, connectors 232, such as screws, pins, etc., extend through plate 231 and extend into the end pieces of devices 10,110. In this case, such end pieces may have corresponding means for receiving the connector 232, such as a threaded hole if the connector 232 is a screw. In this manner, the implant system 230 having the devices 10, 110 connected at one or both ends desirably acts as a single device within the patient's body and adds torsional resistance. Is desirable. It is also conceivable to connect the devices 10, 110 before or after implantation. For example, in one form, the devices 10, 110 separate in a telescoping manner and as only a single plate 231 used to connect the proximal (more accessible) end pieces. Can be embedded in
[0065]
Using two large devices side-by-side, in accordance with the present invention, engages the devices within the endplates of the vertebral body, distracts the disc space and facilitates fusion. These larger diameter devices offer other advantages over using two smaller diameter devices. For example, the deeper the device is inserted into the endplate, the more bleeding bone is exposed, and the greater the opportunity for new bone formation. In addition, smaller diameter devices do not allow sufficient distraction or stabilization within the endplate bone, but allow movement, which will prevent new bone formation. Large diameter devices can be beneficially used in situations where two devices need to be implanted side-by-side (i.e., in both lateral directions), requiring a low degree of lateral exposure.
[0066]
The device design described above with a cylindrical end piece with a notched area can be used with current fusion cages that function as containers or baskets holding autograft chips, and with allograft bone pegs. Can be used. Such a design allows the device to be screwed much closer together, as described for the PLIF method. In addition, instruments that indicate the exact vertical orientation of the cage for full bone growth can also help orient the notches in the intermediate cage to align with the second cage.
[0067]
The present invention contemplates an osteogenic fusion device made of a material strong enough to support adjacent vertebrae and maintain the height of the intervertebral disc space where the implant is mounted. For example, an osteogenic fusion device, such as the osteogenic fusion device 10, can be formed of a biocompatible stabilized metal, such as stainless steel or titanium. Of course, if the material is sufficiently strong, it is conceivable to use certain ceramics, polymers, etc., and other medical grade materials, such as allografts and xenografts. The overall dimensions of each of the above-described osteogenic fusion devices will depend on the location where the implant is mounted. For example, an osteogenic fusion device used in the cervical spine must, of course, be smaller than an osteogenic fusion device used in the lumbar spine. Further, the relative dimensions of the components of the osteogenic fusion device can be varied depending on the location of the vertebra to which the implant is to be mounted. For example, an osteogenic fusion device, such as the osteogenic fusion device 10 used in the lumbar spine, has an outer diameter D of the outer surface 15 of the first end piece 11. ₁ Diameter D which is at least 1/4 of ₂ Central element 13 having In some cases, the lumbar spine generates a bending moment across the osteogenic fusion device, such as the osteogenic fusion device 10, which requires a stronger central element 13.
[0068]
According to the present invention, the illustrated osteogenic fusion device can be push-in or screw-in. Of course, end pieces such as end pieces 11, 12 of osteogenic fusion device 10 and end pieces 111, 112 of osteogenic fusion device 110 enhance the degree of fixation of the osteogenic fusion device between adjacent vertebrae. And various surface features known in the art. For example, the end pieces may include certain roughened surface features that enter the vertebral endplates and resist extrusion of the osteogenic fusion device. Similarly, surfaces such as the outer surfaces 15, 114 and the bone contacting surfaces 20, 115 are provided with a bone ingrowth coating such that a certain amount of bone ingrowth occurs even between the end pieces and the adjacent vertebral bodies. Can be
[0069]
Referring now to FIGS. 45 and 46, another spinal implant of the present invention is illustrated. The implant 240 has two substantially cylindrical end pieces 241, 242 and a central element 243 interconnecting the end pieces 241, 242. The implant 240 is adapted to be implantable with a central element 243 extending in a forward-backward direction. The end pieces 241, 242 have a working portion adapted to resist extrusion of the device 240 from the intervertebral space. These active portions include directional teeth 244 that resist greater movement in one direction than in the other. The illustrated device is easy to insert the end piece 241 first, and then insert the end piece 242. The teeth 244 then resist the transition in the opposite direction, ie, in the direction opposite to the insertion direction. In this way, a conventional push-in device is provided which can be forcibly implanted at the implantation site, either manually or with the aid of a penetrating device.
[0070]
The teeth 244 of the implant 240 are formed as edges of a plurality of generally frustoconical portions 245 of the end pieces 241, 242. The implant 240 also has threaded tool engagement holes 246 and tool engagement slots 247 to cooperate with corresponding components of the insertion tool.
[0071]
47 to 49 show another implant 250 according to the invention having end pieces 251, 252 and a central cylindrical element 253. The end pieces 251, 252 are generally rectangular in shape and have upper surfaces 254, 255 and lower surfaces 256, 257 that contact the respective upper and lower vertebral bodies. The upper surface 254 and the lower surface 255 of the end piece 251 each have a series of directional teeth 258 adapted to resist extrusion. The teeth 258 are formed at their upper surface 254 and lower surface 256 as edges of an elongated wedge-shaped portion 259 extending across the width of the end piece 251. Each of the elongated wedge-shaped portions 259 preferably has a first wall 259A and a second wall 259B that intersect each other at an acute angle of no more than 80 °, more preferably no more than about 60 °. Implant 250 may also have tool engagement holes and tool engagement slots on the outer surface of trailing end piece 252, as shown, for implant 240 of FIGS. 45 and 46.
[0072]
FIG. 50 illustrates a spinal implant similar to that shown in FIGS. 47-49, except that it has directional teeth on the back end piece. In this way, removal and adjustment of the implant after only a partial implantation is easy, due to the small number of directional teeth engaged between the vertebral bodies or no such teeth.
[0073]
FIG. 51 illustrates another implant 260 of the present invention. The implant 260 has the same working portions as the implant 250 described above, except that the implant 260 has directional teeth on the upper and lower surfaces of each of its end pieces 261, 262.
[0074]
FIGS. 52 and 53 illustrate another embodiment of the present invention that is similar in design to implants 250 and 260 except that implant 270 does not have directional teeth or other surface protrusions to resist extrusion from the intervertebral space. Of the implant 270 is shown. Thus, the upper and lower surfaces 271 to 274 of the end pieces 271 and 272 are substantially smooth surfaces that contact adjacent vertebral bodies.
[0075]
Referring to FIGS. 54 and 55, another implant 280 of the present invention is illustrated. The implant 280 has end pieces 281, 282 and central elements 283, 284 and, as shown, is pushed or penetrated with the central elements extending forward-backward. Although made possible, modifications to allow for lateral insertion are also considered to be within the scope of the present invention. The implant 280 is designed as a single spinal implant, unlike an implant that can be placed in both lateral directions like another similar implant. Thus, the generally rectangular end pieces 281, 282 of the implant 280 have a width that is greater than its height, which width substantially spans the lateral dimension of the vertebral body between which the implant is located. Enough to stretch out. End piece 281 provides an upper surface 285 and a corresponding lower surface that contacts the adjacent vertebral body, and end piece 282 also provides an upper surface 286 and a lower surface 287 that contacts the vertebral body. Implant 280 generally also has a centrally located tool engagement hole 288 and tool engagement slot 289, as with the other implants described herein. Implant 280 may also have directional teeth on the upper and / or lower surfaces of end pieces 281 and 282, as described herein for other implants.
[0076]
FIGS. 56-66 illustrate additional spinal implants that can be implanted as a unit within the spinal column. Such spinal implants can be implantable with the central element extending laterally or anterior-posteriorly within the patient's body. Thus, the central element is long enough to place the end pieces at the lateral ends of the vertebral endplates or at the anterior and posterior portions of the vertebral endplates to contact the hard cortical bone of the epiphysis. Let's go.
[0077]
56-58, a view of a spinal implant 290 is illustrated. Implant 290 has end pieces 291, 292 interconnected by a central element 293. End pieces 291 and 292 have upper surfaces 294 and 295 and lower surfaces 296 and 297 that contact the vertebral endplates. In the device shown in FIGS. 55 to 57, these surfaces are substantially smooth. An implant 300 similar to implant 290 is shown in FIGS. 59 and 60, except that it has surface protrusions in the form of directional teeth 309 that resist extrusion. If desired, implant 290, 300 may include a tool engaging hole (eg, a threaded hole) and / or a tool engaging slot on its respective end piece and / or its central element. it can.
[0078]
Each of the end pieces 291, 292 of the implant 290 and the end pieces 301, 302 of the implant 300 has a first generally straight portion to which the central element is attached, and each end of the straight portion is Ends in a curved portion forming an inwardly extending arm that extends inwardly of the point of attachment of the end piece of the central element. In this way, a cavity is formed between the end pieces that is configured to hold the bone forming material.
[0079]
Referring to FIGS. 62 and 63, an implant 310 similar to implants 290, 300 is shown, except that it has substantially arcuate end pieces 311, 312 connected by a central element 313. The arcuate end pieces 311 and 312 are sized and configured to substantially conform to the circumference of the vertebral endplate, extend inward of the end attachment points of the central element, and retain the osteogenic material. To form a space between the end pieces 311 and 312 so as to be able to do so.
[0080]
FIG. 64 illustrates a device 320 similar to device 310 except that it has two central elements. 65 and 66 also have a height approximately equal to the height of the end pieces 331, 332, and thus an arcuate central support for contacting and supporting adjacent vertebral bodies. An implant 330 similar to implant 310 is shown, except that it includes element 335.
[0081]
Referring to FIG. 67, there is illustrated another implant 340 of the present invention having generally cylindrical end pieces 341, 342 connected by a generally cylindrical central element 343. The implant 340 has a first set of threaded portions 344 on the end piece 341 and a second set of threaded portions 345 on the end piece 342 and is adapted to be threadably inserted. Preferably, the first thread 344 and the second thread 345 are discontinuous with each other. Thus, when implant 340 is threadedly inserted, the posterior piece (eg, end piece 342) follows a different thread path than the anterior piece, thereby facilitating anchoring of implant 340 in the disc space and Resists extrusion from the disc space.
[0082]
The invention also provides a method of promoting bone fusion growth in the space between adjacent vertebrae. The method includes providing a load bearing member or implant system as described above, preparing an adjacent vertebra to receive the load bearing member or implant system, and, after the providing step, a load bearing member or implant. Preferably, placing the system in the disc space. The load bearing member and the implant system may include an osteogenic material in the cavity of the device, when the vertebra is supported by the opposing end pieces of the device, as described in more detail above. Are positioned so that they can contact adjacent vertebrae.
[0083]
While the invention has been illustrated and described in detail in the drawings and foregoing description, it is to be understood that this is by way of explanation only and not to limit its features; it shows only the preferred embodiments and It is understood that the description is intended and is intended to protect all changes and modifications that fall within the spirit of the invention.
[Brief description of the drawings]
FIG.
1 is a top view of an osteogenic fusion device according to one embodiment of the present invention.
FIG. 2
FIG. 2 is an end view of one end of the osteogenic fusion device shown in FIG. 1.
FIG. 3
FIG. 9 is a top view of one alternative embodiment of an osteogenic fusion device having external threads.
FIG. 4
FIG. 2 is a top cross-sectional view of the osteogenic fusion device shown in FIG. 1 with the bone growth inducing material supported by the osteogenic fusion device.
FIG. 5
FIG. 5 is a cross-sectional view of the osteogenic fusion device and bone growth inducing material shown in FIG. 4 taken along line 5-5 when viewed in the direction of the arrow.
FIG. 6
FIG. 5 is a plan view of a sheet for a bone growth inducing material used with the osteogenic fusion device illustrated in FIG. 4.
FIG. 7
FIG. 3 is an end view of one end of an osteogenic fusion device, such as the osteogenic fusion device of FIG. 1, modified to include an opening.
FIG. 8
FIG. 3 is an end view of one end of an osteogenic fusion device, such as the osteogenic fusion device of FIG. 1, modified to include an opening.
FIG. 9
2 is a partial cross-sectional side view of an intervertebral disc space having an osteogenic fusion device according to FIG. 1 implanted between adjacent vertebrae.
FIG. 10
FIG. 10 is a top view of the upper surface of the vertebral position with the implant shown in FIG. 9 showing the osteogenic fusion device according to the present invention deployed in both lateral directions.
FIG. 11
FIG. 11 is a cross-sectional view of the vertebral segment with the implant shown in FIG. 10 taken along line 11-11 when viewed in the direction of the arrow.
FIG.
FIG. 2 is a top view of an osteogenic fusion device as illustrated in FIG. 1 with a working portion that allows insertion of the osteogenic fusion device.
FIG. 13
FIG. 13 is an end view of the osteogenic fusion device shown in FIG.
FIG. 14
1 is a side view of an insertion tool according to one embodiment of the present invention.
FIG.
FIG. 15 is a top view of the insertion tool shown in FIG. 14.
FIG.
FIG. 9 is a top view of an osteogenic fusion device for restoring the lordosis angle between adjacent vertebrae according to a further embodiment of the present invention.
FIG.
FIG. 9 is a top view of an osteogenic fusion device according to a further embodiment of the present invention.
FIG.
FIG. 9 is a top view of an osteogenic fusion device according to a further embodiment of the present invention.
FIG.
FIG. 19 is an end view of the osteogenic fusion device shown in FIG. 18.
FIG.
FIG. 6 is a top view of an osteogenic fusion device according to another embodiment of the present invention.
FIG. 21
FIG. 21 is an end view of the osteogenic fusion device shown in FIG. 20.
FIG.
FIG. 9 is a top view of an osteogenic fusion device according to a further embodiment of the present invention.
FIG. 23
FIG. 23 is an end view of the osteogenic fusion device shown in FIG. 22.
FIG. 24
FIG. 9 is a top view of an osteogenic fusion device according to a further embodiment of the present invention.
FIG. 25
FIG. 25 is an end view of the osteogenic fusion device shown in FIG. 24.
FIG. 26
26 is a top view of the pair of fusion devices according to FIGS. 24 and 25 arranged in a bilateral configuration within the lumbar spine. FIG.
FIG. 27
FIG. 26 is a top view of the fusion device according to FIGS. 24 and 25 placed in the cervical spine.
FIG. 28
FIG. 4 is an end view of the osteogenic fusion device of the present invention within a surgical window showing that the particular size fusion device cannot fit completely within the surgical window.
FIG. 29
FIG. 29 is an end view similar to FIG. 28, illustrating one embodiment of the implant system of the present invention.
FIG. 30
FIG. 4 is a side view of an osteogenic fusion device according to one alternative embodiment of the present invention.
FIG. 31
FIG. 31 is an end view of one end of the osteogenic fusion device shown in FIG. 30.
FIG. 32
FIG. 32 is an end view of the other end of the osteogenic fusion device shown in FIG. 31.
FIG. 33
FIG. 4 is a perspective view of one alternative embodiment of the osteogenic fusion device of the present invention.
FIG. 34
FIG. 5 is a top view of one alternative embodiment of the implant system of the present invention.
FIG. 35
FIG. 35 is an end view of one end of the implant system illustrated in FIG. 34.
FIG. 36
FIG. 36 is an end view of the other end of the implant system shown in FIG. 35.
FIG. 37
FIG. 5 is an end view of one alternative embodiment of the implant system of the present invention.
FIG. 38
FIG. 6 is a perspective view of one alternative embodiment of the implant system of the present invention.
FIG. 39
FIG. 9 is a perspective view of a further alternative embodiment of the implant system of the present invention.
FIG. 40
1 is an end view of a combined osteogenic fusion device of the present invention.
FIG. 41
FIG. 41 is a perspective view of one of the osteogenic fusion devices shown in FIG. 40.
FIG. 42
FIG. 41 is a perspective view of another of the osteogenic fusion devices illustrated in FIG. 40.
FIG. 43
FIG. 2 is a perspective view of the bone formation fusion device of the present invention having a stopper member.
FIG. 44
FIG. 3 is an end view of a mated osteogenic fusion device connected by a connecting plate according to the present invention.
FIG. 45
1 is a side view of a spinal implant of the present invention.
FIG. 46
FIG. 46 is an end view of the spinal implant of FIG. 45.
FIG. 47
1 is a side view of a spinal implant of the present invention.
FIG. 48
FIG. 48 is an end view of the spinal implant of FIG. 47.
FIG. 49
FIG. 48 is a top view of the spinal implant of FIG. 47.
FIG. 50
FIG. 4 is a side view of another spinal implant of the present invention.
FIG. 51
FIG. 4 is a side view of another spinal implant of the present invention.
FIG. 52
FIG. 4 is a side view of another spinal implant of the present invention.
FIG. 53
FIG. 53 is an end view of the spinal implant of FIG. 52.
FIG. 54
FIG. 3 is a top view of a spinal implant of the present invention having a dual central element.
FIG. 55
FIG. 55 is an end view of the spinal implant of FIG. 54.
FIG. 56
1 is a top view of a spinal implant of the present invention.
FIG. 57
FIG. 57 is an end view of the spinal implant of FIG. 56.
FIG. 58
FIG. 57 is a side view of the spinal implant of FIG. 56.
FIG. 59
FIG. 5 is a top view of another spinal implant of the present invention.
FIG. 60
FIG. 60 is an end view of the spinal implant of FIG. 59.
FIG. 61
FIG. 60 is a side view of the spinal implant of FIG. 59.
FIG. 62
FIG. 9 is a top view of a further spinal implant of the present invention.
FIG. 63
FIG. 63 is an end view of the implant of FIG. 62.
FIG. 64
FIG. 5 is a top view of another spinal implant of the present invention.
FIG. 65
FIG. 11 is a top view of a further spinal implant of the present invention having a central support member.
FIG. 66
FIG. 66 is an end view of the spinal implant of FIG. 65.
FIG. 67
FIG. 4 is a perspective view of another spinal implant of the present invention.

Claims (72)

An implant that promotes fused bone growth in the disc space between adjacent vertebrae,
A load bearing member having opposing end pieces and an elongated central element extending between the end pieces;
The opposing end pieces are dimensioned to maintain an adjacent intervertebral space and the end pieces are configured to contact and support the adjacent vertebrae. Having opposing surfaces,
The central element may be positioned relative to the opposing end piece such that when an adjacent vertebra is supported by the opposing end piece, a void may be defined between the central element and the adjacent vertebra. Dimensions are set,
An osteogenic material having a density that can be retained about the central element, retained around the central element and in the cavity, and wherein a vertebra is supported by the opposing end pieces; An implant for promoting fused bone growth in the disc space between adjacent vertebrae, said osteogenic material being positioned to adhere to adjacent vertebrae. 2. The implant of claim 1, wherein at least one of the opposing end pieces defines a first end piece having a truncated surface, the first end piece being between the two opposing faces. A first dimension, and a second dimension orthogonal to the first dimension, wherein the first dimension is greater than the second dimension, and wherein the first dimension is adjacent to the intervertebral space. An implant that is set to maintain 2. The implant of claim 1, wherein the opposing end pieces have a first end piece and a second end piece, and wherein the two opposing surfaces of at least one of the opposing end pieces are different. An implant having a surface acting portion that resists extrusion from the intervertebral disc space. 4. The implant of claim 3, wherein said surface-acting portion comprises a tooth. 5. The implant of claim 4, wherein said teeth are directional teeth. 6. The implant of claim 5, wherein said opposing end pieces are substantially cylindrical in shape. 7. The implant of claim 6, wherein the teeth are formed as edges of a plurality of generally frustoconical portions. The implant of claim 5, wherein said opposing end pieces are substantially rectangular in shape. 9. The implant of claim 8, wherein the teeth are formed as edges of an elongate wedge that extends across the width of at least one of the opposing end pieces. 2. The implant of claim 1, wherein the opposing end pieces have a width sufficient to extend substantially across a lateral dimension of the disc space. 2. The implant of claim 1, wherein each of said opposing end pieces has a first generally straight portion to which said central element is attached, each end of said generally straight portion having an inwardly extending arm. An implant that ends in a curved section that forms The implant of claim 1, wherein the opposing end pieces are substantially arcuate and configured to substantially conform to the circumferential profile of a vertebral endplate of an adjacent vertebra. 13. The implant of claim 12, comprising two central elements attached to said opposing end pieces. 13. The implant of claim 12, comprising a central support element having a height approximately equal to the height of the opposing end pieces, such that the central support element can contact and support an adjacent vertebra. An implant that is in the form. 2. The implant of claim 1, wherein each of said opposing end pieces has a thread, and wherein a thread on a first end piece of said opposing end piece is a second one of said opposing end pieces. An implant, wherein the implant is discontinuous to the threads on the end pieces, such that the end pieces follow different screw paths when screwed into the disc space. 3. The implant of claim 2, wherein the osteogenic material comprises a paste or a gel. 3. The implant of claim 2, wherein the carrier is a biocompatible sheet wrapped around the central element in the cavity. 18. The implant of claim 17, wherein the osteogenic substance comprises a bone morphogenic protein. The implant of claim 1, wherein at least one of the opposing end pieces has a plurality of openings defined to communicate with the cavity. 2. The implant of claim 1, wherein the two opposing surfaces of each of the opposing end pieces are tapered to accommodate anatomical angles between adjacent vertebrae. 2. The implant of claim 1, wherein said load bearing member comprises a central piece having two opposing surfaces configured to contact adjacent vertebrae, said central piece being located between said opposing end pieces. An implant connected to a central element and bisecting the cavity, wherein the central piece is dimensioned to maintain an adjacent intervertebral space. 22. The implant of claim 21, wherein said central piece is substantially cylindrical. An implant having a vertebral endplate and having an anterior-posterior length to promote fusion bone growth in an intervertebral disc space between adjacent vertebrae,
A load bearing member having opposing end pieces and an elongated central element extending between the end pieces so that the longitudinal axis of the elongated central element can be implanted in the intervertebral disc space with anterior-posterior extension. Comprising the load bearing member,
Two opposing surfaces, the opposing end pieces sized to maintain an adjacent intervertebral space and the end pieces configured to contact and support the adjacent vertebrae The load bearing member has a length that is slightly less than the anterior-posterior length of the disc space, and the opposing surfaces of the opposing end pieces have an elongate axis of the elongate central element. The load bearing member is arranged to be able to contact at least a portion of the anterior and posterior epiphysis of the vertebral endplate when implanted in the disc space in a posteriorly extended state,
The central element may be positioned relative to the opposing end piece such that when an adjacent vertebra is supported by the opposing end piece, an annular cavity may be defined between the central element and the adjacent vertebra. Sized such that the cavity is capable of retaining osteogenic material adapted to be in intimate contact with an adjacent vertebra when the vertebra is positioned around the central element and the vertebra is supported by the opposing end pieces. An implant configured to promote fusion bone growth in the disc space between adjacent vertebrae. 24. The implant of claim 23, wherein at least one of said opposing end pieces is substantially cylindrical. 24. The implant of claim 23, wherein at least one of said opposing end pieces has a substantially rectangular cross section. 24. The implant of claim 23, wherein at least one said opposing surface of said opposing end pieces has directional teeth. 27. The implant of claim 26,
Each of the opposing end pieces defines a first dimension between the two opposing faces;
The implant, wherein the elongate central element defines a central dimension orthogonal to the longitudinal axis and less than the first dimension. 28. The implant of claim 27, wherein the central dimension is no more than about 25% of the first dimension. 29. The implant of claim 28, further comprising an osteogenic material disposed about the central element and retained within the cavity. 30. The implant of claim 29, wherein the osteogenic material comprises an osteogenic substance disposed within a carrier. 30. The implant of claim 29, wherein at least one of the opposing end pieces has a plurality of apertures defined therethrough that communicate with the cavity. An implant that promotes fused bone growth in the disc space between adjacent vertebrae,
A load bearing member adapted to be penetrably implantable within the disc space, the load bearing member having opposed end pieces and an elongated central element extending between the end pieces;
The opposed end pieces are dimensioned to maintain adjacent intervertebral space, and the end pieces are generally planar, configured to contact and support adjacent vertebrae. Having two opposing surfaces,
The central element may be defined with respect to the opposing end piece such that when the adjacent vertebra is supported by the opposing end piece, a void may be defined between the central element and the adjacent vertebra. The implant is dimensioned. 33. The implant of claim 32, wherein the opposing surface comprises a surface feature that resists pushing of the load bearing member from the disc space. 34. The implant of claim 33, wherein the surface features include teeth. 35. The implant of claim 34, wherein the teeth are directional teeth. 33. The implant of claim 32, wherein said opposing end pieces have a substantially rectangular cross section. 37. The implant of claim 36, wherein the opposing surface of at least one of the opposing end pieces comprises directional teeth. 33. The implant of claim 32, wherein each of said opposing end pieces has a substantially straight portion to which said central element is attached, each end of said substantially straight portion forming an inwardly extending arm. An implant that ends in a curved section. 33. The implant of claim 32, wherein the opposing end pieces are configured to follow a circumferential profile of a vertebral body of the adjacent vertebra. An implant system comprising at least first and second load bearing members adapted for bilateral placement between adjacent vertebrae and promoting fusion bone growth in adjacent intervertebral spaces, wherein said load bearing members But,
Two opposing end pieces and an elongated central element extending between the end pieces, wherein the opposing end pieces are configured to contact and support an adjacent vertebra. Has a surface,
The central element may be defined with respect to the opposing end piece such that when the adjacent vertebra is supported by the opposing end piece, a void may be defined between the central element and the adjacent vertebra. Dimensioned,
Being disposed about the central element and being in the form of the cavity capable of holding osteogenic material in intimate contact with an adjacent vertebra when the vertebra is supported by the opposing end pieces;
An implant system, wherein at least the load bearing member has at least one opposing end piece having a truncated surface dimensioned to nest within the second load bearing member. 42. The implant system of claim 40, wherein the opposing end pieces include a first end piece and a second end piece, wherein the first end piece includes a truncated surface, A first dimension between two opposing surfaces and a second dimension orthogonal to the first dimension, wherein the first dimension is greater than the second dimension, and wherein the first dimension is An implant system configured to maintain adjacent intervertebral space. 42. The implant system of claim 41, wherein the second end piece of the load bearing member has a non-circular truncated surface between the two opposing surfaces. 43. The implant system of claim 42, wherein said non-circular truncated surface is substantially flat. 44. The implant system of claim 43, wherein the first end piece of the load bearing member has an arcuate surface. 46. The implant system of claim 44, wherein each of the two opposing surfaces of the second end piece has an arcuate surface. 46. The implant system of claim 45, wherein the first end piece of the second load bearing member is substantially cylindrical and nests within the first end piece of the first load bearing member. An implant system that fits into the formula. 47. The implant system of claim 46, wherein the first end piece of the second load bearing member has a truncated surface. 43. The implant system of claim 42, wherein said truncated surface is concave. 43. The implant system of claim 42, wherein each of the load bearing members is retained within each of the voids and is arranged to contact an adjacent vertebra when the vertebra is supported by the opposing end pieces. An implant system further comprising an osteogenic material. 50. The implant system of claim 49, wherein the osteogenic material comprises an osteogenic substance disposed within a carrier. 51. The implant system of claim 50, wherein the carrier is a collagen sheet wrapped around the central element at each of the cavities of the load bearing member. 51. The implant system of claim 50, wherein the bone forming substance is a bone morphogenic protein. 51. The implant system of claim 50, wherein at least one of the two opposing faces of the end piece has a thread. An implant system for promoting fusion bone growth in an adjacent intervertebral space,
At least two implants adapted to be placed bilaterally between adjacent vertebrae and sized to be introduceable into the space between adjacent vertebrae, the implants nesting with each other; Osteogenesis that is configured to form voids between adjacent vertebrae when the adjacent vertebrae are supported by the opposing end pieces, the voids promoting unshielded bone growth between adjacent vertebrae An implant system configured to hold a material. In a method of promoting fusion bone growth in an adjacent intervertebral space,
(A) providing a load bearing member having opposing end pieces and an elongated central element extending between the end pieces;
The opposing end pieces have two opposing surfaces configured to contact and support adjacent vertebrae;
The central element may be positioned relative to the opposing end piece such that when the adjacent vertebra is supported by the opposing end piece, a void may be defined between the central element and the adjacent vertebra. Dimensioned such that the cavity is capable of holding osteogenic material adapted to be in intimate contact with an adjacent vertebra when the vertebra is positioned around the central element and the vertebra is supported by the opposing end pieces. And that
(B) preparing said adjacent vertebra to receive a load bearing member in the intervertebral space between adjacent vertebrae;
(C) after said preparing step, placing a load bearing member in the intervertebral space. 56. The method of claim 55, wherein the load bearing member is retained within the cavity and comprises an osteogenic material positioned to contact an adjacent vertebra when the vertebra is supported by the opposing end pieces. The method further comprises: 56. The method of claim 55, wherein at least one of the opposing end pieces has a first dimension between the two opposing surfaces and a second dimension orthogonal to the first dimension. A method defining a piece, wherein said first dimension is greater than said second dimension, said first dimension being set to maintain an adjacent intervertebral space. 56. The method of claim 55, wherein the load bearing member is inserted into the disc space with the longitudinal axis of the elongate central element extending anterior-posterior, wherein the load bearing member is greater than the anterior-posterior length of the disc space. A method having a slightly shorter length such that the opposing surfaces of the opposing end pieces contact at least a portion of anterior and posterior epiphyses of a vertebral endplate. In a method of promoting fusion bone growth in an adjacent intervertebral space,
Implanting at least two implants sized to be introduceable into the intervertebral space into the space between adjacent vertebrae, the implants nesting into one another and the adjacent vertebrae into the opposite vertebrae A form that is capable of forming a void between adjacent vertebrae when supported by the end pieces that are capable of retaining an osteogenic material that promotes unobstructed bone growth between adjacent vertebrae. It is a method. 60. The method of claim 59, wherein the implants nest together. In a method of promoting fusion bone growth in an adjacent intervertebral space,
(A) providing an implant having an elongate central body sized to be introduceable into an adjacent intervertebral space, the body having opposing end pieces, at least one of the opposing end pieces being cut; A truncated surface having opposing surfaces defining an entrance to the notched region, wherein the notched region is defined by the truncated surface;
Causing the bone growth inducing material to be positioned around the central body and to be in intimate contact with an adjacent vertebra when the central body is in an adjacent intervertebral space;
(B) preparing the adjacent vertebra to receive the implant in the intervertebral space between adjacent vertebrae;
(C) after the preparing, placing the implant in the intervertebral space. An implant system for promoting fusion bone growth in an adjacent intervertebral space, comprising at least first and second load bearing members adapted to be laterally disposed between adjacent vertebrae, the load bearing member comprising: A first member includes a male member, a second member of the load bearing member includes a female member, and the male and female members cooperate to resist lateral separation of the device. So, the implant system. 63. The system of claim 62, wherein the load bearing member is substantially cylindrical in shape. 63. The system of claim 62, wherein at least one of the load bearing members has an outer surface configured to resist pushing of the load bearing members out of space. 63. The system of claim 62, wherein each of the load bearing members comprises:
Two opposing surfaces configured with opposing end pieces and an elongated central element extending between the end pieces, the opposing end pieces configured to contact and support adjacent vertebrae Has,
The central element may be positioned relative to the opposing end piece such that when an adjacent vertebra is supported by the opposing end piece, a void may be defined between the central element and the adjacent vertebra. Sized such that the cavity is capable of holding osteogenic material that is in intimate contact with an adjacent vertebra when the vertebra is positioned about the central element and the vertebra is supported by the opposing end pieces;
The first load bearing member comprises at least one opposing end piece having the male member;
The system wherein the second load bearing member comprises at least one opposing end piece having the female member. 66. The system of claim 65, wherein the end pieces are substantially cylindrical in shape. 63. The system of claim 62, wherein each of the end pieces of the first load bearing member has a male member and each of the end pieces of the second load bearing member has a female member. 63. The system of claim 62, wherein each of the first and second load bearing members comprises an end piece having a male member and an end piece having a female member. 63. The system of claim 62, wherein the first and second load bearing members are configured to nest together. 63. The system of claim 62, wherein the male and female members are engagable by axially moving the first and second devices relative to each other. In a method of promoting fusion bone growth in an adjacent intervertebral space,
(A) providing an implant having first and second load bearing members adapted for bilateral placement between adjacent vertebrae, the load bearing members comprising:
Two opposing end pieces and an elongated central element extending between the end pieces, the opposing end pieces configured to contact and support an adjacent vertebra. Has a surface,
The central element may be positioned relative to the opposing end piece such that when the adjacent vertebra is supported by the opposing end piece, a void may be defined between the central element and the adjacent vertebra. Sized and configured such that the cavity is capable of holding osteogenic material in close contact with an adjacent vertebra when the vertebra is positioned about the central element and the vertebra is supported by the opposing end pieces;
At least the first load bearing member includes at least one opposing end piece having a truncated surface configured to nest within the second load bearing member;
Providing a bone growth inducing material disposed about the central body and disposed in intimate contact with an adjacent vertebra when the central body is in an adjacent intervertebral space;
(B) preparing the adjacent vertebra to receive the implant within the intervertebral space between adjacent vertebrae;
(C) placing the implant in the intervertebral space after the preparing step, wherein the implant promotes fused bone growth in the adjacent intervertebral space. In implant systems,
An insertion tool,
An implant mounted to the insertion tool, the load bearing having opposed end pieces and an elongated central element extending between the end pieces to promote fused bone growth in the disc space between adjacent vertebrae. A member, wherein the opposing end pieces have two opposing surfaces configured to contact and support adjacent vertebrae, wherein the opposing end pieces are located between adjacent vertebrae. Sized to maintain space, the central element may define a void between the central element and an adjacent vertebra when the adjacent vertebra is supported by the opposing end pieces. And an implant sized with respect to the opposing end piece and wherein the cavity is configured to hold osteogenic material.