Method and apparatus for spinal fixation

• US 6,296,665 B1
• Filed: 03/20/2000
• Issued: 10/02/2001
• Est. Priority Date: 03/20/2000
• Status: Expired due to Term

• Current Assignee: Zimmer Biomet Spine, Inc. (Zimvie Incorporated)
• Original Assignee: Electro-Biology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Strnad, Lee A., Bailey, Kirk J.
• Primary Examiner(s): Hirsch, Paul J.
• Application Number:
  US09/531,847
• Time in Patent Office: 561 Days
• Field of Search: 623/17.16, 623/17.15
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/2846 Support means for bone substitute or for bone graft implants, e.g. membranes or plates for covering bone defects nets or sleeves applied to surface of endoprostheses A61F2/30907; bone plates A61B17/80; bone regeneration in dental surgery A61C8/0006
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• 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 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 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30485 plastically deformable
• CPC Class Codes: A61F 2002/30495 using a locking ring
• 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 2002/30578 having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30784 Plurality of holes
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30892 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 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

An apparatus for spinal fixation has a longitudinally extending core which provides structural integrity and allows for bone growth along the center column of the spine. The apparatus for spinal fixation further includes upper and lower platform members radially extending from upper and lower ends, respectively, of the core. The platform members each include a plurality of radially extending arms which define substantially triangular openings therebetween. The openings permit bone ingrowth therethrough to the space between the upper and lower platform members which is interrupted only by the core.

Claims

1. An apparatus for spinal fixation comprising:

a core longitudinally extending along an axis;

an upper platform member radially extending about the axis; and

a lower platform member radially extending about the axis;

at least one of the upper and lower platform members including a plurality of radially extending arms defining openings therebetween for permitting bone ingrowth.

2. The apparatus for spinal fixation of claim 1, wherein both the upper and lower platform members include a plurality of radially extending arms.

3. The apparatus for spinal fixation of claim 1, wherein the plurality of radially extending arms includes at least a first arm extending in a generally posterior direction and at least a second arm extending in a generally anterior direction.

4. The apparatus for spinal fixation of claim 3, wherein the second arm is substantially longer than the first arm.

5. The apparatus for spinal fixation of claim 1, wherein the platform member of the at least one of the upper and lower platform members includes an outer rim interconnecting an end of each of the plurality of radially extending arms.

6. The apparatus for spinal fixation of claim 1, wherein the at least one of the upper and lower platform members is substantially kidney-shaped.

7. The apparatus for spinal fixation of claim 1, wherein a space between the upper and lower platform members is interrupted only by the core.

8. The apparatus for spinal fixation of claim 1, wherein the core is extendable along the axis.

9. The apparatus for spinal fixation of claim 8, wherein the core includes first and second telescopically related portions.

10. The apparatus for spinal fixation of claim 8, wherein a first portion of the core telescopically receives a second portion of the core, the first portion including an inwardly extending locking ring engaging a locking groove formed on the second platform.

11. An apparatus for spinal fixation comprising:

a core longitudinally extending along an axis; and

an upper platform member and a lower platform member, the upper and lower platform members radially extending from an upper end and a lower end of the core, the platform members both radially extending about the core and including a plurality of radially extending arms, both the platform members further including a rim connecting an end of each arm of the plurality of arms.

12. The apparatus for spinal fixation of claim 11, wherein the rims of both the upper and lower platform members have a kidney shape.

13. The apparatus for spinal fixation of claim 11, wherein the plurality of radially extending arms includes at least a first arm extending in a generally posterior direction and at least a second arm extending in a generally anterior direction.

14. The apparatus for spinal fixation of claim 13, wherein the second arm is substantially longer than the first arm.

15. The apparatus for spinal fixation of claim 11, wherein a space between the upper and lower platform members is interrupted only by the core.

16. The apparatus for spinal fixation of claim 11, wherein the core is extendable along the axis.

17. The apparatus for spinal fixation of claim 16, wherein the core includes first and second telescopically related portions.

18. The apparatus for spinal fixation of claim 16, wherein a first portion of the core telescopically receives a second portion of the core, the first portion including an inwardly extending locking ring engaging a locking groove formed on the second platform.

19. A method of stabilizing a spinal column comprising the steps of:

selecting an apparatus including a core extending along a longitudinal axis and upper and lower platforms members radially extending from an upper end and a lower end of the longitudinal axis, respectively, both of the upper and lower platforms including a plurality of radially extending arms, adjacent arms defining openings;

implanting the apparatus into a spinal column; and

opposing flexion of the spinal column with at least a first of the plurality of radially extending arms; and

opposing extension of the spinal column with at least a second of the plurality of radially extending arms.

20. The method of stabilizing a spinal column of claim 19, further comprising the step of permitting bone ingrowth through the openings.

21. The method of stabilizing a spinal column of claim 19, further comprising the step of expanding the core along the longitudinal axis.

22. The method of stabilizing a spinal column of claim 19, wherein the first of the plurality of radially extending arms is substantially longer than the second of the plurality of radially extending arms.