Intervertebral disc implant

• US 6,187,048 B1
• Filed: 11/17/1997
• Issued: 02/13/2001
• Est. Priority Date: 05/24/1994
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Surgical Dynamics Incorporated (Medtronic Plc)
• Inventors: Millan, Edith Jane, Arrowsmith, Paul, Milner, Richard
• Primary Examiner(s): Milano, Michael J.
• Application Number:
  US08/971,582
• Time in Patent Office: 1,184 Days
• Field of Search: 623/16, 623/17, 623/18, 623/17.12, 623/17.16, 606/60, 606/61
• US Class Current: 623/17.12
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30589 Sealing means
• 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: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C08L 33/06 of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical

Abstract

An implant for forming an intervertebral disc nucleus pulposus prosthesis includes a conformable material adapted to fill cavities within the disc and to at least partially polymerize in-situ to form a shaped, resiliently deformable prosthesis.

Claims

1. An implant for forming an intervertebral disc nucleus pulposus prosthesis comprising a conformable material adapted to fill cavities within the disc and to at least partially polymerize in-situ to form a shaped, resiliently deformable prosthesis, said conformable material including at least approximately 85% by weight of a compound selected from the group consisting of polyhydroxyalkylmeth acrylates, polyalkylmethacrylates, and mixtures thereof.

2. An implant according to claim 1 wherein the conformable material is in the form of a fluid.

3. An implant according to claim 1 wherein at least part of the material is a functionalised prepolymer.

4. An implant according to claim 1 wherein at least part of the material is adapted to cured upon contact with water.

5. An implant according to claim 1 wherein at least part of the material is adapted to be cured by radiated energy.

6. An implant according to claim 5 wherein said radiated energy is thermal radiation or UV light radiation.

7. An implant according to claim 5 wherein said material further comprises an initiator.

8. An implant according to claim 3 wherein said material comprises a monomer oligomer or polymer comprising ethylenic unsaturation.

9. An implant according to claim 8 wherein said ethylenic unsaturation is acrylic or methacrylic unsaturation.

10. An implant according to claim 2 wherein the material is contained in a flexible envelope.

11. An implant according to claim 10 wherein the envelope is impervious to the material.

12. An implant according to claim 10 wherein the envelope contains means to allow ingress of a second material.

13. An implant according to claim 12 wherein the ingress means is sealable.

14. An implant according to claim 10 wherein the envelope is formed from water permeable polyurethane.

17. The method of claim 10 wherein the step of subjecting including introducing the aqueous solution into the intervertebral disc area to mix with the conformable material.

15. A method for implanting an intervertebral disc prosthesis into an intervertebral disc area defined between adjacent vertebrae comprising the steps of:

introducing a conformable material into the intervertebral disc area, the conformable material including at least approximately 85% by weight of a compound selected from the group consisting of polyhydroxyalkylmeth acrylates, polyalkylmethacrylates, and mixtures thereof, and being adapted to at least partially polymerize in situ; and

curing the conformable material to at least cause partial polymerization thereof to thereby form a resiliently deformable intervertebral prosthesis.

16. The method of claim 15 wherein the step of curing includes subjecting the conformable material to an aqueous solution.

18. The method of claim 16 wherein the step of introducing includes permitting body fluids containing aqueous solution to enter the intervertebral disc area to mix with the conformable material.

19. The method of claim 16 wherein the step of subjecting includes mixing the aqueous solution with the conformable material, the step of mixing being performed prior to the step of introducing the conformable material into the intervertebral disc area.

20. The method of claim 16 further including the step of positioning a flexible container in the disc area and wherein the step of introducing includes directing the conformable material into the flexible container.

21. The method of claim 16 wherein the conformable material is an isocyanate or a siloxane.

22. The method of claim 15 wherein the step of curing includes subjecting the conformable material to radiated energy.

23. The method of claims 20 wherein the flexible container is permeable to the aqueous solution and wherein the step of subjecting includes permitting the aqueous solution to permeate the flexible container.

24. A method for implanting an intervertebral disc prosthesis into an intervertebral disc area defined between adjacent vertebrae, comprising the steps of:

introducing a conformable material into the intervertebral disc area, the conformable material adapted to at least partially polymerize in situ;

curing the conformable material to at least cause partial polymerization thereof to thereby form a resiliently deformable intervertebral prosthesis; and

securing the prosthesis within the intervertebral disc area.

25. The method of claim 24 wherein the step of securing includes using mechanical securing means selected from the group consisting of screws, nails, sutures, and adhesives.

26. A method for implanting an intervertebral disc prosthesis into an intervertebral disc area defined between adjacent vertebrae, comprising the steps of:

positioning an impermeable container in the intervertebral disc area;

introducing a conformable material into the container, the conformable material adapted to at least partially polymerize in situ; and

directing an aqueous solution into the container to at least cause partial polymerization of the conformable material to thereby form a resiliently deformable intervertebral prosthesis.