Spinal implant and method of use

• US 20030199979A1
• Filed: 09/24/2002
• Published: 10/23/2003
• Est. Priority Date: 10/02/2001
• Status: Active Grant

• Current Assignee: REX Medical LP
• Original Assignee: REX Medical LP
• Inventors: McGuckin, James F. Jr.
• Granted Patent: US 7,267,687 B2
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/70 Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
• CPC Class Codes: A61B 2017/00261 Discectomy
• CPC Class Codes: A61B 2017/00557 inflatable A61B2017/22051 takes precedence
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/0256 for the spine
• 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• 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 2210/0014 using shape memory or superelastic materials, e.g. nitinol

Abstract

A spinal implant having a smaller transverse cross-sectional dimension in the radially compressed configuration than in a first expanded configuration and a more linear configuration in the second delivery configuration than in the first curved configuration. The implant assumes the radially compressed configuration and second delivery configuration during delivery to the disc space and assumes the first curved configuration and first expanded configuration upon placement within the disc space. The implant further moves towards the radially compressed configuration once implanted in response to a load placed on the implant by the vertebral bodies.

Claims

1. A spinal implant having a first expanded configuration, a first curved configuration, a second radially compressed configuration, and a second delivery configuration, the implant having a smaller transverse cross-sectional dimension in the radially compressed configuration than in the first expanded configuration and having a more linear configuration in the second delivery configuration than in the first curved configuration, the implant assuming the second radially compressed configuration and second delivery configuration during delivery to the disc space and assuming the first curved configuration and first expanded configuration upon placement within the disc space, the implant further moving towards the radially compressed configuration once implanted in response to a load placed on the implant by the vertebral bodies.

2. The spinal implant of claim 1, wherein the implant is composed of shape memory material with a memorized position in the first expanded configuration and the first curved configuration.

3. The spinal implant of claim 1, wherein the implant is substantially C-shaped in the first curved configuration.

4. The spinal implant of claim 1, wherein the implant forms a closed curve in the first curved configuration.

5. The spinal implant of claim 2, wherein the implant is substantially C-shaped in transverse cross section.

6. The spinal implant of claim 2, wherein the implant is substantially circular in transverse cross section.

7. The spinal implant of claim 2, wherein the implant is substantially rectangular in transverse cross section having at least a first and second substantially planar surface.

8. The spinal implant of claim 1, further comprising an insert material contained within the implant.

9. The spinal implant of claim 8, wherein the insert material is contained within the implant by a tongue and groove arrangement.

10. The spinal implant of claim 2, further comprising an insert material contained within the implant.

11. The spinal implant of claim 10, wherein the insert material is contained within the implant by a tongue and groove arrangement.

12. The spinal implant of claim 1, wherein an outer surface of the implant is roughened to enhance bone ingrowth.

13. The spinal implant of claim 1, wherein the implant includes a plurality of openings in an outer surface to enhance flexibility.

14. The spinal implant of claim 1, wherein the implant includes a plurality of grooves in an outer surface to enhance flexibility.

15. A spinal implant having an outer housing composed of shape memory material, the outer housing having a memorized non-linear configuration and being radially compressible from a first configuration to a second configuration by the vertebral bodies in response to a load placed on the outer housing and returning to its first configuration upon removal of the load.

16. The spinal implant of claim 15, further comprising a filler material disposed within the outer housing.

17. The spinal implant of claim 15, wherein the outer support contains a roughened surface to enhance bone ingrowth.

18. The spinal implant of claim 16, wherein the filler material is retained by a tongue and groove arrangement.

19. A method of minimally invasively inserting a spinal implant in a disc space comprising:

providing a delivery instrument containing the spinal implant in a first configuration;

inserting the delivery instrument through a cannula to the disc space;

deploying the implant from the delivery instrument to position the implant in the disc space, the implant returning towards a memorized second configuration within the disc space; and

removing the delivery instrument and leaving the implant in place, the implant moving between unstressed and stressed positions within the disc space in response to a load placed on the implant.

20. The method of claim 19, further comprising the step of distracting the disc space with an inflatable balloon prior to deploying the implant from the delivery instrument.

21. The method of claim 19, further comprising the step of injecting cold saline into the delivery instrument to maintain the spinal implant in the martensitic state prior to deploying the implant, the implant returning to the austenitic state in response to warming by body temperature when deployed from the delivery instrument.

22. The method of claim 19, further comprising the step removing the disc nucleus through the cannula prior to the step of inserting the delivery instrument through the cannula.