Allogenic intervertebral implant

• US 6,143,033 A
• Filed: 12/23/1998
• Issued: 11/07/2000
• Est. Priority Date: 01/30/1998
• Status: Expired due to Term

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Baker, Kelly J., Carver, Jeffrey L., Paul, David C., Schenk, Beat, Emch, Hansjuerg W.
• Primary Examiner(s): Hirsch, Paul J.
• Assistant Examiner(s): Priddy, Michael B.
• Application Number:
  US09/219,439
• Time in Patent Office: 685 Days
• Field of Search: 623/17, 623/16
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30126 oval-O-shaped
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30828 parallel
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2230/0008 elliptical or oval
• CPC Class Codes: A61F 2230/0019 rectangular

Abstract

An allogenic intervertebral implant for fusing vertebrae is disclosed. The implant is an annular plug conforming in size and shape with end plates of vertebrae. The implant has either an exterior surface identical to that of the harvest bone or an exterior surface machined to have a uniform shape such as an oval or a rectangle. The top and bottom surfaces of the implant have a plurality of teeth to resist expulsion and provide initial stability. The top and bottom surfaces can be either flat planar surfaces or curved surfaces. Preferably, the anterior height of the implant is greater than the posterior height so that the implant is wedge-shaped profile to help restore disc height and the natural curvature of the spine. In one embodiment, the top and bottom surfaces each have a channel oriented in the anterior, lateral, or anterolateral direction for receiving a surgical instrument. The implant can also have a hole for attachment of an inserter. Although the interior space formed by the annular plug can be the natural shape defined by the medullary canal, the medullary canal walls can be machined so that the implant has a uniform interior space.

Claims

1. An intervertebral implant comprising an annular plug of allogenic bone conforming in circumferential size and shape with end plates of vertebrae, wherein top and bottom surfaces of the implant include a plurality of teeth provided in a two dimensional array with the teeth being spaced apart from one another for interlocking with adjacent vertebrae, and wherein the teeth have a saw tooth shape defined by a first side extending perpendicularly to the respective top and bottom surfaces of the implant and a second side oriented at an acute angle to both the first side and the respective top and bottom surfaces of the implant.

2. The implant of claim 1, wherein the implant has a wedge-shaped profile to help restore disc height and spine curvature.

3. The implant of claim 2, having an anterior height which is greater than a posterior height to produce the wedge-shaped profile.

4. The implant of claim 1, wherein the top and bottom surfaces each have a channel for receiving a surgical instrument.

5. The implant of claim 4, wherein the channels run in an anterior-posterior direction.

6. The implant of claim 4, wherein the channels run in an anterolateral direction.

7. The implant of claim 4, wherein the channels run in a lateral direction.

8. The implant of claim 1, wherein at least one side of the implant has at least one hole for attachment of an inserter.

9. The implant of claim 8, wherein the at least one hole is threaded.

10. The implant of claim 8, wherein the at least one hole is provided in an anterior, anterolateral, or lateral side.

11. The implant of claim 1, wherein the top and bottom surfaces are parallel and are spaced by a distance that approximates that of an intervertebral disc.

12. The implant of claim 1, wherein the top and bottom surfaces are curved surfaces which are contoured to mimic the end plates of the adjacent vertebrae.

13. The implant of claim 1, wherein an exterior surface has a uniform shape.

14. The implant of claim 13, wherein the exterior surface has an oval shape.

15. The implant of claim 13, wherein the exterior surface has a rectangular shape.

16. The implant of claim 13, wherein the annular plug includes an interior surface of a machined wall.