WO2014173664A2 - Appareil et procédés pour fixer ensemble des fragments osseux - Google Patents

Appareil et procédés pour fixer ensemble des fragments osseux Download PDF

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Publication number
WO2014173664A2
WO2014173664A2 PCT/EP2014/056835 EP2014056835W WO2014173664A2 WO 2014173664 A2 WO2014173664 A2 WO 2014173664A2 EP 2014056835 W EP2014056835 W EP 2014056835W WO 2014173664 A2 WO2014173664 A2 WO 2014173664A2
Authority
WO
WIPO (PCT)
Prior art keywords
elongate
flexible strap
strap
elongate flexible
face
Prior art date
Application number
PCT/EP2014/056835
Other languages
English (en)
Other versions
WO2014173664A3 (fr
Inventor
Lluis Chico Roca
Salvador Llas Vargas
Montserrat Charles-Harris Ferrer
Original Assignee
Neos Surgery, S.L.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/869,748 external-priority patent/US20140100573A1/en
Application filed by Neos Surgery, S.L. filed Critical Neos Surgery, S.L.
Publication of WO2014173664A2 publication Critical patent/WO2014173664A2/fr
Publication of WO2014173664A3 publication Critical patent/WO2014173664A3/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/82—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin for bone cerclage
    • A61B17/823—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin for bone cerclage for the sternum
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
    • A61B17/842—Flexible wires, bands or straps
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
    • A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
    • A61B17/8869—Tensioning devices

Definitions

  • the disclosure relates to apparatus and methods for securing together bone segments.
  • FIG. 1 illustrates an anterior view of a patient ' s sternum 20 and associated ribs 28 following a median sternotomy.
  • a cut 22 that runs the length of the sternum 20 typically divides the sternum into first and second halves 24 and 26, respectively. After the surgical procedure is performed, the sternum must be closed so that the two halves 24,26 of the sternum are brought into tight abutment with one another.
  • Past methods for joining the severed parts of the sternum have included the use of steel wires that are wound around the severed parts and then twisted to place the parts in tight abutment.
  • Other methods involve the use of flexible straps that are looped about the split portions of the sternum and then tightened to affix the split portions together.
  • U.S. Patent No. 5,462,542 is an example of such a method wherein tightening of the strap is achieved by the surgeon grasping an end of the strap and pulling the strap end in a tensioning direction until the sternum portions are joined together in an adjacent face-to-face contacting relation.
  • a problem with this prior approach is that the ability to tension the straps is limited due to the stiffness of the straps and the small surface area available for being grasped. As a result of the limited ability of the straps to be tensioned arise the problem of there not always being a good conformity of the strap with the bone segments being joined. This can result in the unwanted existence of gaps between the strap and the bone portions which may lead to sternal dehiscence, a condition with serious clinical consequences.
  • the Sternal ZipFix SystemTM currently sold by Synthes CMF utilizes a handheld stainless steel application instrument (Part No. 03.501.080) that is slid over the loose end of the flexible strap, and by use of a trigger mechanism operated by the surgeon applies tension to the strap to effectuate a tight joining of the split sternum parts.
  • the flexible strap of the Sternal ZipFix SystemTM like the flexible strap in the '542 patent above, has a working length (the length of the strap that is intended to be applied against the sternum bone segments) that is straight before being looped around the sternum parts and has a generally uniform flexibility along its length. These characteristics make it difficult for the strap to properly conform to the contour of the sternum.
  • the Synthes® Sternal ZipFix SystemTM attempts to address this problem with the use of the application instrument that is adapted to apply an ample amount of tension to force the strap into conformity with the parts of the sternum.
  • the application instrument must be sterilized after each use which involves time and money resources and a risk of infection to patients if not properly sterilized.
  • the sternum bone mass may be thin or osteoporotic. In such patients the large amount of force that is required to be applied to the strap in order to achieve conformity with the sternum and to reduce the existence of gaps between the strap and sternum can cause the strap to crush the underlying bone, and may in severe instances result in a cut through the bone.
  • a certain expansion of the bone tissue to be repaired should be provided to accommodate movement such as when the thoracic cage expands on coughing.
  • an apparatus for tightly securing together first and second bone segments having peripheral surfaces comprises one or more bends, the apparatus comprising: an elongate flexible strap having a proximal end and a distal end and capable of being formed and maintained in a loop configuration about the first and second bone segments; and the elongate flexible strap having a first elongate portion situated between the proximal end and the distal end, the first elongate portion of the elongate flexible strap being more flexible than one or more other portions of the elongate flexible strap, the first elongate portion configured to extend across at least one of the one or more bends of one or both of the first and second bone segments when the apparatus is tightly looped about the first and second bone segments.
  • an apparatus for tightly securing together first and second bone segments having peripheral surfaces comprising one or more bends
  • the apparatus comprising: an elongate flexible strap having a proximal end and a distal end, the elongate flexible strap having a plurality of ratchet teeth disposed along an elongate distal portion thereof; a locking head situated at the proximal end of the elongate flexible strap, the head defining a transverse channel with a ratchet member situated therein, the channel dimensioned to receive the elongate distal portion of the elongate flexible strap, the ratchet member having one or more teeth adapted to engage the ratchet teeth of the elongate flexible strap in a manner that permits movement of the elongate distal portion of the elongate flexible strap through the channel in only one direction, the elongate distal portion of the elongate flexible strap adapted to be advanced through the channel until the apparatus assumes a secured state
  • an apparatus for tightly securing together a first bone segment with a second bone segment comprising: an elongate flexible strap having a proximal end and a distal end, the elongate flexible strap having a plurality of ratchet teeth disposed along an elongate distal portion thereof; a locking head situated at the proximal end and unitarily formed as a single piece with the elongate flexible strap, the head defining a transverse channel
  • the elongate distal portion of the elongate flexible strap includes features that facilitate the formation of a loop therein suitable for receiving and being gripped by one or more fingers of a human hand.
  • FIG. 1 illustrates an anterior view of a typical patient ' s sternum and associated ribs.
  • FIG. 2 illustrates a cross-section view of a portion of the sternum along line A- A of FIG. 1.
  • FIG. 3 A illustrates a side view of a fixation device according to an implementation.
  • FIG. 3B illustrates a top view of the fixation device of FIG. 3 A.
  • FIG. 3C illustrates an isometric view of the fixation device of FIG. 3 A.
  • FIG. 3D illustrates a form of the fixation device of FIG. 1 when partially looped about a sternum bone mass.
  • FIG. 3E illustrates a fixation device having a locking head with a transverse channel that is arranged substantially parallel to the longitudinal axis of the device.
  • FIG. 4A illustrates a cross-sectional side view of a head region of a fixation device according to an implementation.
  • FIG. 4B illustrates a top view of the head region depicted in FIG. 4A.
  • FIG. 4C illustrates a cross-sectional side view of a locking head according to some implementations.
  • FIG. 4D illustrates a cross-sectional side view of the locking head depicted in FIG. 3E according to some implementations.
  • FIG. 5 illustrates a fixation device secured about the bone fragments of a sternum according to an implementation.
  • FIG. 6A illustrates a side view of a fixation device according to an implementation.
  • FIG. 6B illustrates a partial perspective view of the fixation devices of FIG. 6A.
  • FIGS. 7A-7E illustrate exemplary cross-sectional views of the enhanced flexibility region(s) a fixation device according to various implementations.
  • FIG. 8 illustrates a top view of a fixation device according to an implementation.
  • FIGS. 9A-B illustrate the dimensional characteristics of the fixation device of FIGS. 6A-B according to some implementations.
  • FIG. 10 illustrates a fixation device adapted to the formation of a loop at a distal end thereof than can be gripped by a hand of the surgeon according to an implementation.
  • FIGS. 11A-B illustrate exemplary distal end portions of a fixation device according to some implementations.
  • FIGS. 12A-B illustrate apparatus and method of applying tension to a strap of a fixation device according to some implementations.
  • FIG. 13 illustrates apparatus and method of applying tension to a strap of a fixation device according to another implementation.
  • FIG. 14 illustrates apparatus and method of applying tension to a strap of a fixation device according to another implementation.
  • FIGS. 15A-B illustrate apparatus and method of applying tension to a strap of a fixation device according to another implementation.
  • FIG. 16 illustrates an implementation of a bone fragments fixation device having an active region.
  • FIG. 17 illustrates another implementation of a bone fragments fixation device having an active region.
  • FIG. 18 illustrates another implementation of a bone fragments fixation device having an active region.
  • FIGS. 19-22 illustrate different exemplary means of joining an active region to a strap of bone fragments fixation device.
  • FIG. 23 illustrates a fixation device according to another implementation.
  • FIG. 24 illustrates a fixation device according to another implementation.
  • FIG. 2 illustrates a cross-section view along line A-A of FIG. 1 with the sternum having a cut 22 that divides it into the sternum halves 22 and 24.
  • the cross- sectional shape of the sternum generally comprises elongate top and bottom surfaces 30 and 31 that are joined at their ends by first and second bent surfaces 32 and 33.
  • the top and bottom surfaces 30,31 typically possess some curvature as shown in FIG. 2, but generally appear relatively flat in nature as compared to the bent ends 32,33 that possess a large degree of curvature along a short distance.
  • the top surface 30 may have a generally concave shape and the bottom surface 31 may have a generally convex shape.
  • the top and bottom surfaces 30,31 and first and second ends 32,33 are joined together at corners 32a, 32b, 33a and 33b.
  • the use of flexible straps to join the split halves of a sternum together are known.
  • the thickness of the strap must be large enough to endow the strap with a sufficient amount of strength to bring and maintain the sternum halves in tight abutment without the risk of the strap breaking.
  • the polymeric straps have a rigidity that inhibits conformability with the cross-sectional shape of the sternum without an ample amount of force being applied to the straps.
  • devices like the Sternal ZipFix SystemTM require the use of special heavy duty applicators to apply such force.
  • the rigidity of such devices makes it difficult to minimize the existence of gaps between the straps and the bone segments they join.
  • FIGS. 3A-D illustrate various views of a bone fragments fixation device 40 according to one implementation.
  • FIGS. 3A-C show the fixation device 40 in a rest/as- manufactured condition, while FIG. 3D shows the device partially looped about the sternum bone mass 20.
  • the fixation device 40 includes an elongate flexible strap 41 that extends between a locking head 42 at one end and a needle 50 at the opposite end.
  • the flexible strap 41 and locking head 42 comprise a unitary structure moulded from a polymeric material, such as PEEK.
  • the needle 50 is made of a material that is sufficiently rigid to pierce the tissue that surrounds the bone fragments to be joined (such as sternum halves 22 and 24) so that the fixation device 40 may be looped around the bone fragments.
  • the needle 50 is made of a biocompatible metallic material, such as stainless steel.
  • the needle may also be made of other materials such as, for example, polymers, ceramics and composites.
  • the needle 50 may be secured to the strap 41 using any of a variety of conventional means such as bonding, crimping, welding, molding, riveting, etc.
  • the needle 50 is capable of being removed from the strap 41 in order to create a free end of the strap 41.
  • a needle is not provided at the distal end of the flexible strap 41, the flexible strap in such an instance having a free end.
  • the strap 41 has a top surface 43 and a bottom surface 44 with a plurality of ratchet teeth 45 disposed along an elongate distal portion of the strap.
  • the locking head 42 located at the proximal end of the fixation device 40, defines a transverse channel 46 with a ratchet member 47 situated therein (see also FIGS. 4 A and 4B).
  • the ratchet member 47 has one or more teeth 47a adapted to engage the ratchet teeth 45 on the top surface 43 of the strap 41 in a manner that permits movement of the distal portion of the strap 41 through the channel 46 in the direction indicated by the arrow M in FIG. 4 A.
  • the distal portion of the strap 41 is adapted to be advanced through the channel 46 of the locking head 42 until the fixation device 40 assumes a looped configuration about the sternum halves 22,24 as shown in the example of FIG. 5.
  • the locking head 42 is arranged with the transvers channel 46 and ratchet member 47 being disposed non-orthogonal to the longitudinal axis 120 of the strap 41, and in some implementations disposed parallel or substantially parallel to the longitudinal axis 120 of the strap 41 as shown in FIGS. 3E and 4D.
  • An advantage of this arrangement is that it provides greater flexibility in the positioning of the locking head 42 when the fixation device 40 is securely tightened about the sternum halves 22,24.
  • the ratchet teeth 45 are disposed on the bottom surface 44 of the strap 41.
  • the ratchet member 47 is attached to the wall 53 within the locking head 42 and faces in a direction opposite to that shown in FIG. 4A.
  • the strap 41 has a proximal elongate portion A, an intermediate elongate portion B and a distal elongate portion C, wherein the intermediate elongate portion B is more flexible than the distal elongate portion C.
  • the intermediate elongate portion B is more flexible than each of the proximal and distal elongate portions A and C.
  • the location and length of the elongate portion B results in the elongate portion B being placed across the entirety of bend 33, including corners 33a and 33b upon the fixation device 40 assuming a looped configuration about the sternum 20.
  • Other configurations are also contemplated, as will be discussed in more detail below.
  • the intermediate elongate portion B of the strap 41 includes an elongate through opening 48 that extends through the top and bottom surfaces 43 and 44 of the strap 41, the existence of the through opening 48 endowing the intermediate elongate portion B with a greater degree of flexibility than at least the distal elongate portion C, and in some implementations with a greater degree of flexibility than both of the proximal and distal elongate portions A and C.
  • an elongate strip 49a and 49b On each side of opening 48 is disposed an elongate strip 49a and 49b, the elongate strips constructed to act together to provide the intermediate elongate portion B with an enhanced level of flexibility with respect to elongate portion C (or elongate portions A and C) while also providing the intermediate elongate portion B with a sufficient amount of strength to withstand the tensile and bending stresses imparted thereon when the fixation device 40 is tightly looped about the sternum 20 to bring the sternum halves 22,24 into tight abutment.
  • the proximal and intermediate elongate portions A and B have a width dimension Wl that is greater than the width dimension W2 of the distal elongate portion C.
  • the greater width dimension of Wl provides several advantages. First, it provides for flexibility in the design of the through opening 48 and strips 49 allowing them to be tailored to meet the requirements associated with fixating a variety of different types of bone fragments. Secondly, it assists in positioning and stabilizing the fixation device 40 during its placement about bone fragments to be joined. For example, as shown in FIG.
  • the proximal elongate portion A includes a bend 52 at its proximal end where it is joined with the locking head 42.
  • the bend 52 may be contoured to rest on the upper corner 32a of the sternum halve 22 (see FIG. 3D).
  • Providing a wider footprint at the bend 52 assists in ensuring a proper placement of the fixation device 40 as it is initially positioned on the sternum 20 and also assists in maintaining the fixation device 40 in a proper angular orientation about the sternum as it is being affixed thereto.
  • the locking head 42 has a curved inner side 51 that is also adapted to rest on a portion of the upper corner 32a of sternum halve 22.
  • the fixation device 40 comprises a flexible strap that is straight, or substantially straight, when the fixation device is in the rest/as-manufactured state (not shown in the figures).
  • the flexible strap 41 comprises a curved portion D that lies partially or fully within the enhanced flexibility region B of the strap 41. In the implementation of FIG.
  • the curved portion D begins at or near the proximal end of elongate portion B and extends distally to a location at or near the onset of the ratchet teeth 45.
  • the curved portion D includes a first segment Dl that has a curvature that is partially or completely complementary to the curvature of the bend 33 of the sternum halve 24.
  • the curved portion D also includes a second segment D2 distal to the first segment Dl that is adapted to extend toward the bottom surface 31 of the sternum 20 when the fixation device 40 is initially loosely looped about the sternum halves 22 and 24.
  • the configuration of the curved portion D results in the strap assuming a loop about the sternum halves 22 and 24 that when tightened has a perimeter that is smaller than is otherwise achievable without the existence of the curved portion D. That is, it has an optimized perimeter with respect to the perimeter of the bone cross- section.
  • the second segment D2 extends across all, or at least a significant portion of the bottom surface 31 of the sternum 30. In the implementation of FIG. 6 the second segment D2 extends across only a portion of the bottom surface 31 of the sternum 30.
  • first segment Dl assists in initially adapting the fixation device 40 to the sternum 20 and minimizes the existence of gaps between the strap 41 and the sternum 20 after the device assumes its tightly secured state about the sternum halves 22 and 24.
  • second segment D2 assists in minimizing the existence of gaps between the strap 41 and the bottom surface 31 of the sternum 20 by it extending toward the bottom surface 31 of the sternum 20 as partially shown in FIG. 3D.
  • the configuration of the second segment D2 is selected so that it readily assumes a straight or substantially straight profile when the strap 41 is securely tightened about the sternum halves 22 and 24. As shown in FIGS.
  • the bottom surface 31 of the sternum 20 can comprise a curved surface that approximates a convex curve.
  • the configuration of the second segment D2 causes the second segment D2 to at least partially approximate the curvature of the bottom surface 31 of the sternum 20 when the fixation device 40 assumes a secured state about the sternum, to minimize the existence of gaps between the strap 41 and the sternum 20.
  • a through opening 48 that extends between the top and bottom surfaces 43 and 44 of the strap 45 endow the intermediate elongate portion B of the strap 41 with greater flexibility than the distal elongate portion C or with a greater flexibility of both the proximal and distal elongate portions A and C.
  • openings that extend only partially through the strap 41 are used to achieve, along with other dimensional and material characteristics, a desired flexibility and strength of the intermediate elongate portion B.
  • FIGS. 7A-E illustrate cross-section views of the intermediate elongate portion B of the strap 41 according to some implementations.
  • FIG.7A illustrates a cross-section according to what is depicted in the implementations of FIGS. 3 and 6.
  • each of the strips 49a and 49b comprise a trapezoidal cross-section wherewith a larger surface area is provided along the bottom surface 44 of the strap 41 as compared to the top surface 43 of the strap.
  • Such a configuration provides a number of advantages. First, it enables the inclusion of a relatively large opening while still providing the bottom surface 44 of the strap 41 with an area for contacting the outer surface of the sternum 20 that is relatively large.
  • the smaller cross-section of the strips 49a and 49b at and near the top surface 43 advantageously contributes most in enhancing the flexibility of the intermediate elongate portion B. For a given opening size, it further maximizes the cross-sectional area of the strips 49a and 49b. By maximizing the cross-sectional area of the strips 49a and 49b, the strips are more easily designed to withstand the tensile and bending stresses imparted upon them when the fixation device 40 is tightly looped about the sternum 20 in the secured state. In the implementation of FIG.
  • the opening 48 is in the form of a recess or channel that extends only partially through the strap 41.
  • the large contact area provided at the bottom surface 44 of the strap 41 allows a greater amount of force to be applied to the strap 41 without a risk of having the strips 49a and 49b cutting through the bone mass.
  • the opening 48 and strips 49a and 49b may each comprise rectangular shapes as depicted in FIG. 7C.
  • Multiple through openings 48 or partial openings e.g. recesses/channels
  • a combination of through openings and non-through openings e.g., recesses/channels
  • the corners formed by the inclusion of the opening(s) in the intermediate elongate portion B may be rounded for the purpose of reducing stress concentrations in said regions.
  • an opening is provided only within the elongate region B.
  • an elongate opening or recess separate to or contiguous with opening (or recess) 48 may be provided in a region of the strap 41 distal to intermediate elongate portion B.
  • an elongate opening or recess may extend distally and terminate proximal to the location of the ratchet teeth 45.
  • the opening or recess may extend distally into the ratchet teeth 45. The same holds true for the implementation of FIG.
  • an elongate opening or recess separate to or contiguous with opening (or recess) 48 may be provided in a region of the strap 41 distal to intermediate elongate portion B.
  • an elongate opening or recess may extend distally into the ratchet teeth 45 as shown in FIG. 8.
  • the opening or recess 48 may extend across each of corners 33a, 33b and 32b of the sternum 20.
  • strap 41 may contain a series of spaced-apart openings or recesses in lieu of a single elongate opening.
  • the provision of multiple spaced-apart openings can assist in maintaining the structural integrity of the strap 41 without significantly affecting its flexibility.
  • the openings may be strategically placed to provide enhanced flexibility only in designated regions, such as those that are intended to coincide with portions of the bends 32 and 33 of the sternum 20. For example, according to some implementations a first opening is provided that extends across the corners 33a and 33b of bend 33, and a second opening is provided that extends across the corner 32b of bend 32. Other opening/recess configurations are also contemplated.
  • the fixation device may comprise the dimensional characteristics A- J as illustrated in FIGS. 9A-B.
  • Dimension A may be between about 180 to about 380 millimeters (about 7 to about 15 inches).
  • Dimension B may be greater than or equal to about 150 millimeters (greater than or equal to about 6 inches).
  • Dimension C may be between about 45 to about 55 millimeters (about 1.8 to about 2.2 inches).
  • Dimension D may be between about 20 to about 35 millimeters (about 0.8 to about 1.4 inches).
  • Dimension E may be between about 20 to about 25 millimeters (about 0.8 to about 1.0 inches).
  • Dimension F may be between about 3.5 to about 4.5 millimeters (about 0.138 to about 0.183 inches).
  • Dimension G may be between about 3.5 to about 5.0 millimeters (about 0.138 to about 0.196 inches).
  • Dimension H may be between about 0.7 to about 1.2 millimeters (about 0.03 to about 0.047 inches).
  • Dimension I may be between about 5.5 millimeters (about 0.22 inches).
  • Dimension J may be a radius of curvature of about 40 millimeters or less (about 1.6 inches or less).
  • the needle 50 (if present) is removed from the flexible strap 41 in order to create a free end of the strap 41.
  • the free end of the strap 41 is adapted for being inserted into the channel 46 of the locking head 42 in a direction indicated by arrow M in FIG. 4A.
  • the ratchet teeth 45 on the top surface 43 of the strap 41 come into engagement with the teeth 47a of the ratchet member 47 of the locking head 42.
  • an amount of force effective to secure the bone fragments together may be achieved by simply gripping and pulling on a distal portion of the strap 41 with a human hand or with the use of a standard surgical tool, such as surgical forceps.
  • a standard surgical tool such as surgical forceps.
  • the length of strap 41 protruding from the topside surface of the locking head 42 may be severed from the fixation device 40 by simply bending the strap 41 back and forth along the topside surface of the locking head until it breaks.
  • Other methods of severing the excess length of the strap 41 may also be used such as a cutting by use of scissors or other type of cutting tool.
  • a distal portion of the strap 41 is equipped with features that permit the formation of a loop 60 after the distal portion has been passed through the locking head 42.
  • the loop 60 is formed by passing the free end 61 of the strap 41 through an opening 62 in the strap as shown in FIG. 10.
  • the loop 60 advantageously provides the surgeon with means for securely gripping the distal end portion of the fixation device by inserting one or more fingers through the loop. This enables the surgeon to apply a greater amount of tension to tighten the strap 41 about the bone fragments 22 and 24 than is otherwise possible without the existence of the loop 62.
  • the distal end portion 63 of the strap 41 possesses one or more features that are adapted to engage with a tab in the opening 62 and/or the side walls of the opening 62 so that advancement of the distal end portion 63 through the opening 62 is permitted only in the direction indicated by the arrow M in FIG. 10.
  • the distal end portion 63 comprises a set of flat, flexible and angular wings 64 that are serially disposed along its length as shown in FIG. 11 A. In practice, upon the fixation device 40 being looped bout the bone fragments 22 and 24 with the distal end portion 63 having passed through the locking head 42, the loop 60 is formed by passing at least a one of the angular wings 64 through the opening 62.
  • FIG. 1 1B shows another implementation wherein ratchet teeth 65 provided on a surface of the distal end portion 63 are adapted to engage with a tab 66 within the opening 62 to prevent, or otherwise inhibit, a movement of the distal end portion 63 in a direction opposite to that indicated by the arrow M once the loop 60 is formed.
  • a locking head force applicator 70 is provided, as shown in FIG. 12 A, that has a bottom surface 71 adapted to rest against the topside surface 72 of the locking head 42.
  • the applicator 70 has first and second surfaces 73 and 74 that are adapted for being acted upon by the thumb and index finger of a surgeon engaged in the operation of securing together bone fragments 22 and 24.
  • the applicator 70 has a through opening (not shown) through which freely passes the distal end portion of the strap 41.
  • the applicator 70 is passed over the distal end portion of the strap 41 until the bottom surface 71 rests against the topside surface 72 of the locking head 42 as shown in FIG. 12 A. Thereafter, the surgeon may grip the distal end portion of the strap 41 with the use of a hand or with a gripping tool, such as forceps 77 (as shown in FIG 12B) while holding the applicator 70 against the topside surface 72 of the locking head 42. The surgeon then, while applying an upward force U by the use of only a hand or with the use of standard surgical forceps 77 as shown in FIG.
  • a force applicator 80 adapted for being coupled with the distal end portion of the strap 41 is provided as shown in FIG. 13.
  • the applicator 80 possesses a through opening 81 for receiving the distal end portion of the strap 41.
  • the applicator is T-shaped so as to provide surfaces that enable it to be firmly gripped by the hand of a surgeon.
  • the distal end portion of the strap 41 includes ratchet teeth 82 that are adapted to engage a ratchet member (not shown) disposed within the through opening 81.
  • the ratchet member and ratchet teeth 82 are configured to permit the distal end portion of the strap to be advanced only in an upward direction (as viewed in FIG. 13).
  • the applicator 80 may be gripped with the hand of the surgeon and pulled upward as indicated by the arrows U in FIG. 13 to effectuate a secure tightening of the bone fragments 22 and 24.
  • the applicator 70 may be used in conjunction with the applicator 80 to apply the tension for securing the bone fragments tightly together.
  • the applicators 70 and 80 are made of a polymeric material, such as, for example PEEK. It is appreciated, however, that the applicators may be made of any of a variety of materials. It is also important to note that the shape of the applicators 70 and 80 may vary and are not limited to the shapes depicted in the accompanying figures. Applicator 80 may, for example, take the form of an L-shape, spherical or semi-spherical shape or any other shape capable of being gripped by the human hand.
  • a kit that includes a requisite number of fixation devices 40 necessary for properly securing the target bone fragments together.
  • the kit includes one or more fixation devices 40 and an applicator 70.
  • the kit includes one or more fixation devices 40 and an applicator 80.
  • the kit includes one or more fixation devices 40 and both of applicators 70 and 80.
  • the applicators 70 and 80 are trash disposable after their use with there being no need to employ post-operative sterilization procedures.
  • FIG 14 illustrates a partial cross-section view of a tensioning apparatus 90 useful in inducing an incremental advancement of the distal portion of the strap 41 in the direction of the arrow T once the strap 41 has been initially looped about the bone fragments as depicted.
  • the tensioning apparatus 90 may take an outer form similar to that of the applicator 70 previously disclosed herein.
  • apparatus 90 has a bottom surface 91 adapted to abut against the topside surface 72 of the locking head 42 of fixation device 40.
  • the locking head 42 includes a ratchet member that interacts with ratchet teeth disposed on the upper surface of the strap 41 in a manner as previously disclosed.
  • the apparatus 90 is adapted to receive and act upon the distal portion of the strap 41 to induce a tensioning of the strap as the apparatus is rotated back and forth in the directions indicated by arrows Rl and R2.
  • a ratchet member 93 configured to engage with ratchet teeth 95 on the strap 41 as shown in FIG. 14.
  • the ratchet member 93 acts on one the top surface 43 of the strap 41 while a wall segment 94 of the apparatus 90 acts upon the bottom surface 44 of the strap.
  • a rotation of the apparatus 90 in the direction of Rl causes an incremental advancement of the strap through both the tensioning apparatus 90 and the locking head 42.
  • the lever arm provided by wall 94 enables, by virtue of the rotational movement of the tensioning apparatus 90, a larger tension force to be applied to the strap 41 than would otherwise be possible absent the presence of the apparatus acting on the distal portion of the strap.
  • the ratchet member 93 of apparatus 90 acts in the same way as the ratchet member 47 of the locking head 42 in that it functions to permit movement of the strap in a single direction, the direction of arrow T.
  • the apparatus 90 After having been rotated in the direction Rl to induce a distal advancement of the strap through the locking head 42 and apparatus 90, the apparatus 90 is rotated in the direction R2 to assume a rest position as depicted in FIG. 14.
  • the apparatus 90 may be repeatedly rotated in the afore-described manner until a desired tensioning of the strap 41 is achieved, the desired tensioning being that amount sufficient to bring the bone fragments 22 and 24 into tight abutment with one another.
  • FIG. 15 illustrates another tool and method of incrementally inducing a distal advancement of the strap 41 through the locking head 42 in order to achieve a desired tensioning of the strap.
  • the tool 100 (shown in partial cross-section) comprises a body 101 having a bottom surface 102 for resting against the topside surface 72 of the locking head 42.
  • the body 101 includes a first opening 103 that passes through a bottom portion of the body, the opening 103 communicating with a larger opening 104 located in a top portion of the body, there being a force bearing surface 105 situated at the junction of openings 103 and 104.
  • a gripping tool 110 is inserted into opening 104 so that an end surface 111 of the gripping tool 110 abuts the force bearing surface 105. While in this ready position the gripping tool 110 is made to firmly grip the distal portion of the strap as shown in FIG. 15 A. Thereafter, while the strap is being firmly gripped and the end surface 111 is in abutment with surface 105, the gripping tool 110 is rotated in the direction of arrow R, as shown in FIG. 15B. As a result of the rotation the strap 41 is caused to incrementally advance distally through the locking head 42 in the direction of arrow T. According to one implementation the gripping tool 110 is rotated about 90 degrees to effectuate the distal advancement.
  • angular rotations other than 90 degrees may also be employed.
  • the strap is released from gripping tool 110 to permit it to rotate back to its original angular orientation.
  • the gripping and rotating steps are repeated until the desired amount of tension is achieved.
  • the manner of maintaining the fixation device 40 in a looped configuration is accomplished with the use of teeth 45 disposed along a length of the strap 41 that interface with a ratchet member 47 located within the locking head 42.
  • teeth 45 disposed along a length of the strap 41 that interface with a ratchet member 47 located within the locking head 42.
  • means other than teeth on the strap cooperating with a ratchet member in the locking head are employed to facilitate the formation and maintaining of the fixation device in a looped configuration.
  • One example includes the use of rings disposed at a proximal end of the fixation device 40 wherewith a portion of the strap 41 is interwoven with the rings in a manner that permits the strap to be advanced in a forward direction through the rings while at the same time preventing, or otherwise inhibiting, a backward movement of the strap through the rings.
  • Other examples include the use of protuberances, or other features, disposed at the proximal end of the fixation device 40, either on the strap itself or within a locking head, that are adapted to engage with other features on the strap to effectuate the formation and maintenance of a loop.
  • FIGS. 16-24 depict fixation devices according to a variety of other implementations.
  • the devices consists of an oblong element, of biocompatible material and of a sufficient length to loop round aligned bone fragments, such as the bone fragments of the sternum bone, and are provided with an adapted passage to be able to insert one end of the oblong element through it to form a slip loop, the passage and oblong element being provided complementary means of retention that prevent the oblong element from slipping through the passage in the opposite direction to that of insertion.
  • oblong element consists of two portions or longitudinal parts of a different nature, one of them being an active strip of a material with a pseudoelastic alloy, preferably superelastic, the configuration of which prevents it passing through the means of insertion, so the loop formed is liable to display a first perimeter LI temporarily and during its implementation around the bone fragments when the active strip is deformed; and a second perimeter L2 when the active strip recovers its nominal shape either due to disappearance of an effort applied to it, or due to a thermal effort or both, fulfilling the condition that L1>L2. This preferably occurring without further slipping of the oblong element through the passage once the loop is formed.
  • Pseudo elasticity is known as the situation in which major deformations are obtained by increasing the load that may be recovered when discharged at a constant temperature.
  • Superelasticity, as well as what is known as the rubber effect, are particular cases of pseudoelasticity.
  • the active strip is a material with a memory thermal effect providing the possibility of that stretch to recover its nominal shape after effort is applied at low temperature, when that active stretch is heated up again.
  • the lack of tension that may be applied to the loop due to the tightening being applied manually may compensate the reduction of the perimeter of the loop formed when the active strip recovers its nominal shape.
  • the fixation devices combine materials of a different nature and not all the device is comprised of the active material, for example with shape memory.
  • a device formed fully with material with memory would cause a variation in the perimeter of the loop formed in an uncontrolled manner, as its perimeter during its formation varies considerably according to the parameters of the patient. In other words, the absolute variation in length of the perimeter would vary significantly according to the length of the loop formed.
  • Providing a device with one or several active strips with a preset length, that shall be the same regardless of the length of the loop formed it allows one to select optimum retraction values taking into account the statistical perimeter that may have the loop formed for a specific use. In other words, it allows one to select retraction values that make it possible for a same device to adequately fulfil its function for a wide spectrum of population for a specific use, such as repairing a sternum after a sternotomy.
  • the active strip has the property of retracting between 2 mm and 8 mm on going from L to /. More preferentially, to retract between 3.5 and 6.5 mm to repair the bone tissue of the sternum.
  • the active strip is connected by at least one of its ends to a longitudinal strip of the oblong element that is formed by a mouldable material.
  • the active strip includes means that permit it to be anchored in the mouldable material for safe connection to it.
  • the shape of the active strip or strips is selected so a loop formed and subject to manual tightening around a bone tissue generates a torque exceeding 200 N so that strip recovers its nominal shape.
  • an end of the oblong element is adapted to be bent and linked on top of itself to form a pulling grip.
  • the device includes a component that exerts a force on the active strip to keep it stretched, that component being adapted to be manipulated in order for it to cease to act on the active strip once the loop is formed.
  • FIGS. 16-18 illustrate fixation devices according to some implementations.
  • device 1 is formed by an oblong element 2 in strip form, in which two ends, 2a and 2b, are distinguished.
  • a protrusion is formed at end 2a of the oblong element 2, preferably with a flat supporting surface to which reference shall be made later on, equipped with an orifice 3, assigned to receive the insertion of opposing end 2a of the oblong element to form a the loop 4.
  • Figures 1 to 3 show device 1 with the loop 4 already formed.
  • the passage 3 and the oblong element 2 are equipped with complementary means of retention 5, that are not displayed in detail (as they are known) that prevent the oblong element 2 from slipping through passage 3 in the opposite direction to that of insertion, so the loop 4 formed cannot be undone.
  • the oblong element may be provided with retaining teeth on one of its faces, passage 3 having a similar section to the portion of the oblong element 2 that will go through it, equipped with a flexible tongue inside that shall act as a ratchet on the toothed part of the oblong element.
  • the protrusion of end 2b of the oblong element 2 has a surface, when loop 4 is formed, that faces the inside of the flat the loop 4, to favour its support against the bone tissue to be restored, that shall be bound or tied firmly by device 1.
  • the oblong element 2 of the devices in FIGS. 16-18 include portions or longitudinal strips of a diverse nature, attached or linked together, each one of which forms an active strip 6 that has the virtue of acting when there is a temperature change. Active strip 6 is of a material with thermal memory effect, with superelastic properties, and its configuration prevents it slipping through passage 3 to guarantee that it shall always be placed on the portion of the oblong element 2 looped so as to form the loop 4.
  • the active strip 6 is located in a zone adjoining end 2b of the oblong element, between two stretches 7 of a mouldable plastic material, that is flexible, not elastically deformable, of which one forms the widening in which passage 3 is located, and the other is extended to end 2a of the oblong element 2, which is foreseen to have a slightly curved shape.
  • thermal memory effect refers to the capacity of the material, when submitted to heating, to recover from the plastic deformation to which it may be submitted under low temperature conditions.
  • the active strip 6 is made of an alloy known commercially as nitinol, that is an equiatomic alloy of Nickel-Titanium, that has the effect bi-directionally, which means that at certain temperature, it has a first shape that may change upon a change in temperature, but if the first temperature is recovered, the first shape is also recovered. This is achieved by thermo-conforming the material for each shape at each temperature.
  • the active strip 6 is deformed at a temperature between 0°C and 5°C stretching it; device 1 is applied on the patient's body, forming the loop 4 around the bone tissue to be repaired, for example around the sternum after a sternotomy, and naturally, at body temperature, the active strip 6 retracts, that is, it goes back to its nominal shape, that is shorter, thus causing a reduction in the perimeter of the loop 4 formed.
  • the active strip 6 is configured in a spring shape. More specifically, it has the shape of a filiform element in a cylindrical helix. This spring shaped geometry allows major elastic stretching of the active strip 6 without suffering plastic deformation. The force exerted by the spring may be directly proportional to the deformation applied.
  • the active strip 6 has a ring shape.
  • the ring-shaped geometry allows a spring effect to be generated with an essentially flat profile.
  • the regularity of the geometry minimizes the concentrations of tensions and thus the weak points and allows a folded and stretched position to be maintained externally, that may be released and folded to the nominal shape by activation of a simple mechanism if necessary.
  • the active strip 6 is configured in sheet form. More specifically, it is formed by a sheet of nitinol equipped with a series of perforations distributed regularly over its surface. In the example, the perforations are aligned, forming various rows that run in an essentially transversal direction to the longitudinal axis of the oblong element 2. In each row, the distance that separates two consecutive perforations remains constant.
  • the plate shaped geometry allows a greater effort to be generated with an essentially flat shape.
  • the mechanism to allow the geometry to superelastically recover its nominal shape, if necessary, may be very simple.
  • the levels of deformation that are obtained at an equal length of the active strip 6 are lower than the preceding two variations, although the force exerted is greater.
  • the dimensions of the possible geometric forms are selected so the active strip 6 retracts a distance between 2 mm and 8 mm, which would mean a reduction in the perimeter with a the loop 4 that forms the binding of a sternum between 2.5% and 10%, according to the size of the sternum.
  • FIGS. 19A-B show schematic views of the longitudinal section and plan view, respectively, so as to link or join the active strip 6 of a device 1 with an adjoining strip of the same oblong element 2 that forms the device 1.
  • the end of the active strip 8 is configured in a plate shape and is equipped with anchorage means 8, formed in the example by passing orifices, that are embedded in the plastic material of which that stretch 7 is constituted, adjoining the oblong element 2. This is achieved by overmolding the plastic around the end of the active strip 6 equipped with anchorage means 8.
  • FIGS. 20-22 show alternatives for a firm, non-separable union of the active strip 6 of a device 1 to a longitudinal strip 7 of the oblong element 2 that runs next to it.
  • FIG. 23 represents a device 1 in which the oblong element 2, specifically its end 2a, is adapted to bend and loop on itself to form a pulling grip 9 that shall facilitate the tightening operation of the loop 4 around the bone tissue.
  • the oblong element 2 may be placed in a position near to the tip of end 2a of the oblong element 2 of a similar passage to that which allows the loop 4 to be formed.
  • this passage and the strip of the oblong element 2 may be equipped with complementary means of retention to prevent the pulling grip 9 becoming undone when pulling on it.
  • FIG. 24 shows an example of device 1 that is especially fit to take advantage of the pseudoelastic properties of the active strip 6.
  • the active strip 6 is subject to effort that causes recoverable stretching of the material forming the active strip 6.
  • Device 1 is applied to the bone tissue with a component 10 that exerts a force on the active strip 6 to keep it stretched, that component being adapted for handling in order for it to cease to act on the active strip 6 once the loop 4 is formed, which would cause the active strip 6 to recover its nominal shape, shortening the perimeter of the loop 4.
  • the active strip 6 may be formed by titanium or nitinol.

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  • Health & Medical Sciences (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Neurology (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Prostheses (AREA)
  • Surgical Instruments (AREA)

Abstract

L'invention porte sur un appareil qui permet de fixer ensemble un premier et un second segment d'os dont les surfaces périphériques comportent une ou plusieurs courbes. Dans certains modes de réalisation, le dispositif de fixation comprend une sangle souple et allongée ayant une extrémité proximale et une extrémité distale, la sangle souple et allongée ayant une pluralité de dents de cliquet, disposées le long d'une partie distale et allongée de la sangle souple et allongée, qui fonctionnent avec un élément à cliquet à l'intérieur d'une tête de verrouillage située au niveau de l'extrémité proximale afin de permettre la formation d'une boucle fermée autour des fragments d'os. Dans certains modes de réalisation, la sangle souple et allongée présente une première partie allongée, située entre la tête de verrouillage et la partie distale allongée, la première partie allongée de la sangle souple et allongée étant plus souple que la partie distale allongée de la sangle souple et allongée, la première partie allongée étant conçue pour s'étendre sur la courbe ou sur au moins une des courbes lorsque l'appareil est dans un état fixé.
PCT/EP2014/056835 2013-04-24 2014-04-04 Appareil et procédés pour fixer ensemble des fragments osseux WO2014173664A2 (fr)

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Application Number Priority Date Filing Date Title
US13/869,748 US20140100573A1 (en) 2012-10-08 2013-04-24 Apparatus and methods for securing together bone fragments
US13/869,748 2013-04-24

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WO2014173664A3 WO2014173664A3 (fr) 2014-12-24

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT201800005439A1 (it) * 2018-05-16 2019-11-16 Dispositivo di riduzione di fratture

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4570618A (en) * 1983-11-23 1986-02-18 Henry Ford Hospital Intervertebral body wire stabilization
DE4024334A1 (de) * 1990-07-31 1992-02-06 Gundolf Ferdinand Vorrichtung zur osteosynthese von knochenfragmenten, insbesondere zur fixation von knochenfrakturen
FR2704745A1 (fr) * 1993-05-07 1994-11-10 Erpios Dispositif de liaison des extrémités d'un ligament d'ostéosynthèse, notamment d'ostéosynthèse vertébrale.
US20090204118A1 (en) * 2008-02-13 2009-08-13 William Ralph Pratt Surgical cable with malleable leader segment

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4570618A (en) * 1983-11-23 1986-02-18 Henry Ford Hospital Intervertebral body wire stabilization
DE4024334A1 (de) * 1990-07-31 1992-02-06 Gundolf Ferdinand Vorrichtung zur osteosynthese von knochenfragmenten, insbesondere zur fixation von knochenfrakturen
FR2704745A1 (fr) * 1993-05-07 1994-11-10 Erpios Dispositif de liaison des extrémités d'un ligament d'ostéosynthèse, notamment d'ostéosynthèse vertébrale.
US20090204118A1 (en) * 2008-02-13 2009-08-13 William Ralph Pratt Surgical cable with malleable leader segment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT201800005439A1 (it) * 2018-05-16 2019-11-16 Dispositivo di riduzione di fratture
WO2019220284A1 (fr) * 2018-05-16 2019-11-21 Ferrari, Francesco Dispositif de réduction de fracture

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