Implant in particular for replacing a vertebral body in surgery of the spine

• US 6,375,683 B1
• Filed: 01/24/2000
• Issued: 04/23/2002
• Est. Priority Date: 05/02/1997
• Status: Expired due to Term

• Current Assignee: Stryker European Operations Holdings, LLC (Stryker Corporation)
• Original Assignee: Stryker France S.A.
• Inventors: Crozet, Yves, Mangione, Paolo
• Primary Examiner(s): Milano, Micheal
• Application Number:
  US09/423,173
• Time in Patent Office: 820 Days
• Field of Search: 623/17.11, 623/17.15, 623/17.16
• US Class Current: 623/17.15
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/30138 Convex polygonal shapes
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2002/30355 Cylinder of elliptical or oval basis
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30372 with additional means for limiting said translation
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30599 stackable
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/3082 Grooves
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/4638 Tools for performing screwing, e.g. nut or screwdrivers, or particular adaptations therefor
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: B65D 5/006 : Separate corner posts and like elements B65D5/0065 takes precedence
• CPC Class Codes: B65D 5/48022 : formed by two parallel panels located in the base of a tray being folded up towards each other

Abstract

An implant device designed for replacing a vertebral body of the spine. The implant device contains at least one moving member so as to vary the distance between a first and second member. Most preferably this movement is achieved by rotating at least one cam about an axis. The cam or cams are shaped so as to comprise an irregular polygon thus allowing the height of the implant device to be varied at discrete positions. A slidable telescopic engagement device within the implant device affords the added advantage of simple adjustment and maneuverability.

Claims

1. An implant specifically for replacing a vertebral body in surgery of the spine, the implant comprising first and second bearing elements for bearing against under-and overlying vertebral plates, retaining means for retaining the two bearing elements one above the other, and at least one moving member suitable for varying the distance between said bearing elements, the retaining means comprising at least one slideway means provided between the two bearing elements, and in that the or each moving member is constituted by a cam having discrete positions suitable for being rotated about an axis that is essentially horizontal and essentially parallel to the sagittal plane wherein the or each discrete-position cam has, in cross-section, an outline in the form of an irregular polygon.

2. An implant according to claim 1, wherein the or each cam possesses a plurality of pairs of faces, the faces in each pair being mutually parallel, and each pair of faces being spaced apart at a distance (d1, d2, d3) different from the spacing between the other pairs of faces.

3. An implant according to claim 2, wherein the cam has three pairs of faces.

4. An implant according to claim 2 or 4, wherein each bearing element possesses a bearing plate having a groove formed in one face thereof, and in that at least some of the pairs of faces are dimensioned in such a manner as to be of a length in the circumferential direction of the cam that is very slightly shorter than the width of each groove.

5. An implant according to claim 4, wherein the faces of at least one pair of faces of the cam are of a length, in the circumferential direction of the cam, which is matched to the width of the grooves in the bearing plates by means of respective setbacks provided in transitions between said faces and adjacent faces.

6. An implant according to claim 1, wherein the or each cam is mounted to move in rotation and in translation on the or each slideway means.

7. An implant according to claim 6, wherein the or each slideway comprises a hollow slideway-forming upright formed from one element of the implant, and a slider-forming element formed from another element of the implant, and in that the slideway and the slider have elongate openings passing through them to pass a cam-mounting shaft.

8. An implant according to claim 7, wherein the cam-mounting shaft is defined by a screw passing through a central passage of the cam and through said elongate openings, and engaged in a nut.

9. An implant according to claim 8, wherein one of the elongate openings of the slideway is a notch suitable for preventing the nut from rotating.

10. An implant according to claim 1, wherein the bearing elements have teeth on their outside surfaces for engaging in the vertebrae lying over and under the implant.

11. An implant according to claim 1, wherein it comprises two bearing elements and a central element, two cams operating respectively between the top bearing element and the central element and between the bottom bearing element and the central element, and two slidewayforming means operating respectively between the top bearing element and the central element and between the bottom bearing element and the central element.

12. An implant specifically for replacing a vertebral body in surgery of the spine, the implant comprising:

a) a first bearing element and a second bearing element for bearing against underlying and overlying vertebrae;

b) a retainer supporting one of the first bearing element and the second bearing element above the other of the first bearing element and the second bearing element; and

c) at least one moving member for varying the distance between said bearing elements;

d) the at least one moving member comprising at least one cam being rotatable about an axis that is essentially horizontal and having discrete positions with respect to the retainer.

13. The implant of claim 12, wherein the retainer has at least one slideway for engaging at least one of the first bearing element and the second bearing element.

14. The implant of claim 12, wherein the at least one cam has a cross-sectional shape, the cross-sectional shape comprising an irregular polygon.

15. The implant of claim 12, wherein the at least one cam has a plurality of pairs of faces, the faces of each pair being mutually parallel.

16. The implant of claim 15, wherein each pair of faces is spaced apart at a distance different from the spacing between the other pairs of faces.

17. The implant of claim 15, wherein the cam has three pairs of faces.

18. The implant of claim 15, wherein each bearing element has a bearing plate with a face, the bearing plate having a groove formed in the face of the bearing plate.

19. The implant of claim 18, wherein at least some of the pairs of faces are dimensioned so that a length in the circumferential direction is slightly shorter than the width of each groove.

20. The implant of claim 19, wherein the faces of at least one of the pairs of faces have a length in the circumferential direction of the cam, the length being matched to the width of the grooves.