Vertebral fusion device and method

• US 20070173940A1
• Filed: 01/18/2006
• Published: 07/26/2007
• Est. Priority Date: 01/18/2006
• Status: Active Grant

• Current Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Inventors: Hestad, Hugh, Robie, Bruce, Hudgins, Robert, Maertens, Jack
• Granted Patent: US 7,799,079 B2
• Time in Patent Office: Days
• US Class Current: 623/17.120
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 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 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30228 Cylinders of elliptical or oval basis
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30461 sutured, ligatured or stitched
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/30576 with extending fixation tabs
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30586 having two or more inflatable pockets or chambers
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30784 Plurality of holes
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61F 2210/0085 hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• 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 2310/00353 : Bone cement, e.g. polymethylmethacrylate or PMMA

Abstract

A device for facilitating bone fusion of two vertebrae. The device is sized and shaped to at least extend between the two vertebrae to be fused, and includes an outer wall member disposed about an inner portion. A space between the outer wall member and the inner compartment is adapted to contain an osteogenic bone fusion material. The inner portion includes a compartment adapted to contain an inner fill material, such as a bone cement or an in situ curable polymer. The inner portion may operate as a structural member to maintain a desired amount of spacing between the vertebrae to be fused, and to support the spinal column prior to formation of the fused bone joint. The device is also configured to locate the osteogenic material away from the centers of the vertebrae to be fused, providing a fused joint with high bending and torsional rigidity.

Claims

1. An implantable orthopedic device for implantation between opposed vertebral end plates of a pair of vertebrae, the device comprising:

an inner portion including a pair of spaced-apart end caps and an inner wall member there between, wherein the end caps and the inner wall member define a compartment; and

an outer wall member disposed about and coupled to the inner portion, wherein separation between the outer wall member and the inner portion defines an outer space,

wherein the device has a size and shape such that the device can extend between the opposed vertebral end plates such that at least the end caps can be in contact with the vertebral end plates and the outer space can be in communication with the vertebral end plates.

2. The device of claim 1 further comprising a first fill material disposed within the compartment.

3. The device of claim 2 wherein the first fill material comprises a curable polymer.

4. The device of claim 2 wherein the first fill material comprises polymethylmethacrylate.

5. The device of claim 1 further comprising a first portal in fluid communication with the compartment and isolated from the outer space, and a second portal in fluid communication with the outer space and isolated from the compartment.

6. The device of claim 1 further comprising a second fill material disposed within the outer space.

7. The device of claim 6 wherein the second fill material comprises an osteogenic material.

8. The device of claim 1 wherein at least one of the outer or the inner wall members is made substantially from a textile material.

9. The device of claim 8 wherein the textile material is configured to permit longitudinal expansion and resist radial expansion of the at least one of the outer or inner wall members.

10. The device of claim 9 wherein the textile material comprises a braided, woven or knitted textile.

11. The device of claim 1 wherein at least one of the outer or inner wall members is made substantially from a fiber-reinforced elastomeric composite material.

12. The device of claim 1 wherein the end caps are made substantially from a material selected from the group consisting of polyetheretherketone, polyaryletherketone, polyimide, polysulfone, polyethelene therephthalate, polyetherimides, polyurethane, and liquid crystalline polymers.

13. The device of claim 1 wherein the end caps are made substantially from a bone ingrowth material.

14. The device of claim 13 wherein the bone ingrowth material comprises an open cell tantalum material.

15. The device of claim 1 wherein the end caps are made substantially from a biocompatible metal.

16. The device of claim 1 wherein the end caps are made substantially from a material selected from the group consisting of textiles and fiber-reinforced elastomeric composites.

17. The device of claim 1 wherein at least one of the end caps comprises at least one bone engaging projection.

18. The device of claim 17 wherein the at least one bone engaging projection is made substantially from a bone ingrowth material.

19. The device of claim 1 wherein the outer wall member comprises an extendable member adapted to be attached to one of the vertebrae.

20. The device of claim 1 wherein the inner portion is adapted to expand longitudinally from a first state to a second state upon an introduction of a first fill material into the compartment, and wherein the outer wall member is adapted to expand longitudinally substantially concurrently with the inner portion upon the introduction of the first fill material into the compartment, and wherein the device is configured to maintain a desired amount of spacing between the opposed vertebral end plates when the device is in the second state.

21. The device of claim 20 wherein the device is further configured to distract the opposed vertebral end plates by a desired amount.

22. An implantable orthopedic device for implantation between opposed vertebral end plates of a pair of vertebrae, the device comprising:

a pair of spaced apart end caps, wherein at least one of the end caps is configured to be substantially rigid;

a wall member extending between the end caps, wherein the wall member and the end caps define a compartment; and

a curable polymer fill material disposed within and substantially filling the compartment,

wherein the device has a size and shape such that it can extend between the opposed vertebral end plates such that at least the end caps can be in contact with the vertebral end plates.

23. A method of fusing a pair of vertebrae of a spine, the method comprising:

removing a substantial portion of a disc between opposed vertebral end plates of a pair of vertebrae;

creating a first spacing between the opposed vertebral end plates;

inserting an implantable orthopedic device between the end plates, the device comprising;

a compartment having first and second end caps, and

a wall member disposed about the compartment, wherein separation between the wall member and the compartment defines an outer space;

introducing a fill material into the compartment to longitudinally expand the compartment such that the end caps contact the vertebral end plates; and

substantially filling the outer space with an osteogenic material such that the osteogenic material contacts the vertebral end plates.

24. The method of claim 23 further comprising removing a vertebra and adjacent intervertebral discs between the pair of vertebrae to be fused.

25. The method of claim 23 wherein the step of introducing a fill material into the compartment comprises substantially filling the compartment with a curable polymer material.