Fusion implant device and method of use

• US 5,895,426 A
• Filed: 09/06/1996
• Issued: 04/20/1999
• Est. Priority Date: 09/06/1996
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Osteotech Incorporated (Medtronic Plc)
• Inventors: Morris, John W., Scarborough, Nelson
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US08/709,266
• Time in Patent Office: 956 Days
• Field of Search: 623/16, 623/17, 623/18, 606/61
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/1637 Hollow drills or saws producing a curved cut, e.g. cylindrical A61B10/025, A61B17/1695 take precedence
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 2017/0256 for the spine
• 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 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4644 Preparation of bone graft, bone plugs or bone dowels, e.g. grinding or milling bone material bone material A61F2/28; disintegrating or milling devices B02C
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• 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 2002/30233 Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30266 wedge-shaped parallelepipeds
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30828 parallel
• CPC Class Codes: A61F 2002/448 comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2230/0082 parallelepipedal
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated
• CPC Class Codes: Y10S 606/909 : Bone
• CPC Class Codes: Y10S 606/91 : Polymer
• CPC Class Codes: Y10S 606/913 : Monolithic

Abstract

An intervertebral prosthesis includes a bone graft implant member dimensioned for insertion within an intervertebral space defined between adjacent vertebrae and having at least first and second longitudinal sections with respective first and second cross-sectional dimensions. The first cross-sectional dimension of the first implant section is greater than the second cross-section dimension of the second implant section to define a stepped region having a retaining surface. Consequently, upon insertion of the implant member within a generally correspondingly dimensioned receiving bed formed within the adjacent vertebrae, the retaining surface facilitates securement therewithin by corresponding engagement with surfaces of the receiving bed. A method for fusion of adjacent vertebrae utilizing the prosthesis is also disclosed.

Claims

1. An intervertebral prosthesis comprising an implant member dimensioned for insertion within a receiving bed formed in opposed faces of adjacent vertebrae, said implant member defining a longitudinal axis and having a non-threaded outer surface and at least first and second longitudinal sections with respective first and second cross-sectional dimensions, said first cross-sectional dimension being greater than said second cross-sectional dimension to define a retaining surface of said implant member, said retaining surface being positioned, dimensioned and configured such that upon insertion of said implant member into the receiving bed between the vertebrae, said retaining surface facilitates securement therewithin by corresponding engagement with surfaces of the adjacent vertebrae.

2. The intervertebral prosthesis according to claim 1 wherein said implant member is generally circular in cross-section.

3. The intervertebral prosthesis according to claim 2 wherein said second longitudinal section defines a diameter ranging from about 50% to about 95% the diameter defined by said first longitudinal section.

4. The intervertebral prosthesis according to claim 1 wherein the implant member defines a single stepped region.

5. The intervertebral prosthesis according to claim 1 wherein said implant member includes multiple stepped regions.

6. The intervertebral prosthesis according to claim 1 wherein said implant member is a bone graft implant.

7. The intervertebral prosthesis according to claim 1 wherein said implant member comprises cancellous bone or cortical bone.

8. The intervertebral prosthesis according to claim 1 wherein said implant member comprises a material selected from the group consisting of titanium, titanium alloys, surgical steel, polymeric material and ceramic material.

10. The intervertebral prosthesis according to claim 8 wherein said first and second cylindrical sections are concentrically arranged about a longitudinal axis of said implant member.

11. The intervertebral prosthesis according to claim 8 wherein said implant member has a non-threaded exterior surface.

13. The intervertebral prosthesis according to claim 8 wherein said implant member comprises cortical bone.

14. The intervertebral prosthesis according to claim 8 wherein said implant member comprises cancellous bone.

9. An intervertebral prosthesis comprising an implant member of biocompatible material and being dimensioned for positioning in a receiving bed formed in opposed faces of adjacent vertebrae, said implant member including a non-threaded outer surface and first and second generally cylindrical sections, the first cylindrical section defining a diameter greater than a diameter defined by the second cylindrical section, the juncture of said first and second cylindrical sections defining a retaining ledge, the retaining ledge being positioned, dimensioned and configured such that upon insertion of said implant member between the adjacent vertebrae, the retaining ledge prevents movement of the implant member relative to the vertebrae thereby facilitating retainment therein.

12. The intervertebral prosthesis according to claim 9 wherein said implant member defines anterior and posterior ends, said first cylindrical section disposed adjacent said anterior end.

15. A vertebral interbody fusion device comprising a bone graft implant member dimensioned to span an intervertebral space between adjacent vertebrae, said implant member having a non-threaded outer surface and first and second longitudinal sections, with respective first and second cross-sectional dimensions, the juncture of said first and second longitudinal sections defining a retaining surface, said retaining surface being positioned, dimensioned and configured to facilitate retention of said implant member within said intervertebral space through cooperative engagement with corresponding surfaces of the adjacent vertebrae.