Spinal implant

• US 5,609,636 A
• Filed: 01/11/1996
• Issued: 03/11/1997
• Est. Priority Date: 05/23/1994
• Status: Expired due to Term

• Current Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Spine-Tech, Inc. (Sulzer Medica)
• Inventors: Stassen, David W., Kohrs, Douglas W., Yuan, Hansen A.
• Primary Examiner(s): CLARKE, ROBERT A
• Application Number:
  US08/585,297
• Time in Patent Office: 425 Days
• Field of Search: 623/16, 623/17, 623/20, 606/60, 606/61
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• 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 2/447 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 2002/30146 octagonal
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30789 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30858 Threads interrupted by grooves or sidewalls, e.g. flat sidewalls
• CPC Class Codes: A61F 2002/30868 Square, rectangular or rhomboidal threads
• CPC Class Codes: A61F 2002/30879 Ribs
• CPC Class Codes: A61F 2002/30883 dovetail-shaped
• 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 2002/4627 with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2230/0017 Angular shapes
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0082 : parallelepipedal

Abstract

An implant for use in spinal stabilization includes four generally linear thread segments. The thread segments are maintained and spaced apart alignment by rigid supports. The thread segments include a plurality of individual threads with the individual threads of the segments defining a thread pattern. The supports and the thread segments define a hollow implant interior exposed to an exterior of the implant.

Claims

1. An implant for use in spinal stabilization for placement into a disc space between two vertebra having end plates of cortical bone and a vertebra interior of cancellous bone, said implant comprising:

a plurality of generally linear thread segments;

rigid supports for holding said thread segments in spaced apart alignment;

said thread segments including a plurality of individual threads with said individual threads of said segments defining a thread pattern;

said supports and said thread segments defining a hollow implant interior exposed to an exterior of said implant.

2. The implant according to claim 1 wherein said thread segments are disposed in parallel alignment.

3. The implant according to claim 2 wherein said thread segments are supported for said segments to define longitudinal edges of a parallelepiped.

4. The implant according to claim 1 wherein said thread segments include first and second upper segments and first and second lower segments;

said first upper segment and said first lower segment joined in parallel spaced alignment by rigid supports extending perpendicularly therebetween;

said second upper segment and said second lower segment joined in parallel spaced alignment by rigid supports extending perpendicularly therebetween.

5. The implant according to claim 4 wherein said first and second upper segments are joined in parallel spaced alignment by rigid supports and wherein said first and second lower segments are joined in parallel spaced alignment by rigid supports.

6. The implant according to claim 5 wherein said rigid supports joining said first and second upper segments are convex and wherein said rigid supports joining said first and second lower segments are convex.

7. The implant according to claim 5 wherein said rigid supports joining said first and second upper segments and said rigid supports joining said first and second lower segments are spaced apart to define openings in communication with said implant interior.

8. The implant according to claim 1 wherein said implant is sized for said thread segments to reside in said cortical bone of said vertebra when said implant is placed within said bore.

9. A combination insertion tool and implant for fusing two opposing vertebra each having opposing end plates of cortical bone and vertebra interior of cancellous bone and wherein said opposing end plates are separated by a disc space, said combination comprising:

a. an implant having;

1. at least four generally linear thread segments;

2. rigid supports for holding said thread segments in spaced apart alignment with said thread segments defining longitudinal edges of a parallelepiped;

3. said thread segments including a plurality of individual threads with said individual threads of said segments defining a thread pattern selected to mate with a thread pattern of said bore;

11. The combination according to claim 9 wherein said body has a tool bore formed therethrough from said proximal end to said distal end;

an insert having a threaded distal end and sized to be inserted through said tool body;

said implant including a threaded end to mate with said threaded distal end to removable secure said implant within said distal end of said insertion tool.

12. The combination according to claim 9 wherein said body has a tool bore formed therethrough from said proximal end to said distal end;

an insert having a distal end and sized to be inserted through said tool body to abut said implant held within said distal end of said insertion tool;

said insert and said insertion tool threadedly coupled for said insert to urge said implant out of said distal end of said insertion tool upon threading said insert and said insertion tool together.

14. The method according to claim 12 comprising retaining said implant in an insertion tool having a distal end including grips sized to extend between opposing thread segments of said implant with at least two of said grips having external threads selected match said thread pattern and a proximal end connected to said distal end through a tool body, holding said implant with said insertion tool during said threading and threading until said grips oppose said disc space at said full inserted position.

10. said supports and said thread segments defining a hollow implant interior exposed to an exterior of said implant through at least aligned bone-growth openings formed through said implant on opposite sides thereof;

b. an insertion tool having;

1. a distal end including grips sized to extend between opposing thread segments of said implant with at least two of said grips having external threads selected to match said thread pattern;

2. a proximal end connected to said distal end through a tool body.

13. A method for fusing two opposing vertebra each having opposing end plates of cortical bone and vertebra interior of cancellous bone and wherein said opposing end plates are separated by a disc space, said method comprising:

a. forming a threaded bore into said disc space and at least partially into said cortical bone of said opposing end plates;

b. selecting an implant having;

1. at least four generally linear thread segments;

2. rigid supports for holding said thread segments in spaced apart alignment with said thread segments defining longitudinal edges of a parallelepiped;

3. said thread segments including a plurality of individual threads with said individual threads of said segments defining a thread pattern selected to mate with a thread pattern of said bore;

4. said supports and said thread segments defining a hollow implant interior exposed to an exterior of said implant through at least aligned bone-growth openings formed through said implant on opposite sides thereof;

c. threading said implant into said bore to a full inserted position with said thread segments in residence in said cortical bone and with said bone-growth openings opposing said cancellous bone of each of said vertebra.