Wave spring for a spinal implant

• US 9,039,766 B1
• Filed: 06/28/2012
• Issued: 05/26/2015
• Est. Priority Date: 06/30/2011
• Status: Active Grant

• Current Assignee: Arthrex Incorporated
• Original Assignee: MX Orthopedics Corp
• Inventors: Fonte, Matthew
• Primary Examiner(s): Hammond, Ellen C.
• Assistant Examiner(s): NEGRELLIRODRIGUEZ, CHRISTINA
• Application Number:
  US13/536,109
• Time in Patent Office: 1,062 Days
• Field of Search: 606246-249, 623 1711- 1716
• US Class Current: 623/17.13
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• 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 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30566 Helical springs
• CPC Class Codes: A61F 2002/30571 Leaf springs
• CPC Class Codes: A61F 2002/30573 2-D spiral springs
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30754 Implants for interposition between two natural articular surfaces
• CPC Class Codes: A61F 2002/4435 Support means or repair of the natural disc wall, i.e. annulus, e.g. using plates, membranes or meshes
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61F 2230/0065 toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61L 2400/16 Materials with shape-memory or superelastic properties
• CPC Class Codes: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/06 Titanium or titanium alloys
• CPC Class Codes: A61L 27/52 Hydrogels or hydrocolloids
• CPC Class Codes: Y10T 29/49613 for human comfort

Abstract

A spinal implant includes a wave spring configured to surround a nucleus. The spring may be formed from a shape memory material. The implant may further include an artificial nucleus configured to simulate a disc nucleus.

Claims

1. A spinal implant comprising:

a coiled wave spring configured to surround a nucleus, wherein the wave spring is formed with at least one wire having a sinusoidal shape and made of a shape memory material, wherein the shape memory material is tailored to achieve a stress-induced martensitic transformation when a critical stress is exceeded and the shape memory material is further trained to expand to a preset shape when the wave spring temperature exceeds its transition temperature.

2. The spinal implant according to claim 1, wherein the wave spring is wedge shaped.

3. The spinal implant according to claim 1, wherein the shape memory material is selected from the group consisting of Nitinol, a Titanium-Niobium alloy, and combinations thereof.

4. The spinal implant according to claim 1, wherein the wave spring is formed with one or more flat wires.

5. The spinal implant according to claim 1, wherein the wave spring is formed with one or more rectangular wires.

6. The spinal implant according to claim 1, further comprising:

an artificial nucleus configured to simulate a disc nucleus, wherein the wave spring surrounds the artificial nucleus.

7. The spinal implant according to claim 6, wherein the artificial nucleus is made from a polymer material.

8. The spinal implant according to claim 6, wherein the artificial nucleus is made from a hydro-gel material.

9. The spinal implant according to claim 6, wherein the artificial nucleus is a wave spring.

10. A method of forming a spinal implant, the method comprising:

forming a coiled wave spring, the wave spring having at least one wire with a sinusoidal shape and made of a shape memory material, wherein the shape memory material is tailored to achieve a stress-induced martensitic transformation when a critical stress is exceeded and the shape memory material is further trained to expand to a preset shape when the wave spring temperature exceeds its transition temperature; and

configuring the wave spring to surrounding a nucleus.

11. The method according to claim 10, wherein the wave spring is wedge shaped.

12. The method according to claim 10, wherein the shape memory material is selected from the group consisting of Nitinol, a Titanium-Niobium alloy, and combinations thereof.

13. The method according to claim 10, wherein the wave spring is formed with one or more flat wires.

14. The method according to claim 10, wherein the wave spring is formed with one or more rectangular wires.

15. The method according to claim 10, further comprising

forming an artificial nucleus configured to simulate a disc nucleus, wherein the wave spring surrounds the artificial nucleus.

16. The method according to claim 15, wherein the artificial nucleus is formed from a polymer material.

17. The method according to claim 15, wherein the artificial nucleus is formed from a hydro-gel material.

18. The method according to claim 15, wherein the artificial nucleus is formed from a wave spring.

19. A method of implanting a spinal implant, the method comprising:

inserting a coiled wave spring into an intervertebral space, wherein the wave spring is formed with at least one wire having a sinusoidal shape and made of a shape memory material, wherein the shape memory material is tailored to achieve a stress-induced martensitic transformation when a critical stress is exceeded and the shape memory material is further trained to expand to a preset shape when the wave spring temperature exceeds its transition temperature; and

introducing a nucleus material into an interior area of the wave spring, the nucleus material configured to simulate a disc nucleus.

20. A method of forming a spinal implant, the method comprising:

providing a shape memory material with about 30-40% cold work;

coiling a wave spring, the wave spring having at least one wire with a sinusoidal shape and made of the shape memory material, wherein the shape memory material is tailored to achieve a stress-induced martensitic transformation when a critical stress is exceeded; and

subsequently age heat treating the shape memory material after coiling the wave spring.