Spinal Implant with expandable fixation

• US 20090216331A1
• Filed: 02/22/2008
• Published: 08/27/2009
• Est. Priority Date: 02/22/2008
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Coalign Innovations Inc. (Stryker Corporation)
• Inventors: Pretti, Rudy A., Grotz, R. Thomas
• Granted Patent: US 8,932,355 B2
• Time in Patent Office: Days
• US Class Current: 623/17.160
• 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/484 Fluid means, i.e. hydraulic or pneumatic
• 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 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30505 spring biased
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/4693 hydraulic
• CPC Class Codes: A61F 2210/0085 hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2250/0006 for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

A spinal implant which is configured to be deployed between adjacent vertebral bodies. The implant has at least one fixation element with a retracted configuration to facilitate deployment of the implant and an extended configuration so as to engage a surface of an adjacent vertebral body and secure the implant between two vertebral bodies. Preferably, the implant is expandable and has a minimal dimension in its unexpanded state that is smaller than the dimensions of the neuroforamen through which it must pass to be deployed within the intervertebral space. Once within the space between vertebral bodies, the implant can be expanded so as to engage the endplates of the adjacent vertebrae to effectively distract the anterior disc space, stabilize the motion segments and eliminate pathologic spine motion. Angular deformities can be corrected, and natural curvatures restored and maintained.

Claims

1. A spinal implant for placement in a space between adjacent vertebral bodies, comprising:

a. a first surface for engaging an end plate of a first adjacent vertebral body;

b. a second surface for engaging an end plate of a second adjacent vertebral body;

c. at least one extendable fixation element having a distal tip, a contracted configuration within the implant to facilitate deployment of the implant between the first and second vertebral bodies and an extended configuration to extend the distal tip beyond the second surface to engage an end plate of the second adjacent vertebral body and to fix the implant within the space between the first and second adjacent vertebral bodies.

2. The implant of claim 1 wherein the first surface for engaging an end plate of a first adjacent vertebral body includes a base member and the second surface for engaging an end plate of a second adjacent vertebral body includes a pressure applying member.

3. The implant of claim 2 wherein at least one support member cooperates with the base and is coupled to the pressure applying member.

4. The implant of claim 3 wherein the pressure applying member has at least one passageway through which the distal tip of the fixation element extends to engage the base plate of the second vertebral body.

5. The implant of claim 3 wherein the support member is adapted to be extended.

6. The implant of claim 5 wherein the support member is adapted to be extended by fluid.

7. The implant of claim 6 wherein the fluid is hydraulic fluid.

8. The implant of claim 5 wherein the extendable fixation element is extendable with respect to the support member.

9. The implant of claim 5 wherein the extendable fixation element is extendable independent of the support member.

10. The implant of claim 1 wherein the extendable fixation element is adapted to be extended by fluid.

11. The implant of claim 10 wherein the fluid is hydraulic fluid.

12. The implant of claim 10 wherein the hydraulic fluid comprises a curable polymer having a fluid state for providing hydraulic communication of mechanical force to extend the fixation element to engage an adjacent vertebral body.

13. The implant of claim 9 wherein the polymer is cured to a solid state to lock the extended fixation element to hold the spinal implant in the space between vertebral bodies.

14. The implant of claim 13 wherein the polymer comprises methyl methacrylate.

15. The implant of claim 8 wherein the extendable fixation element is slidably disposed within a bore of an extendable member.

16. The implant of claim 15 wherein the extendable fixation element is extended by hydraulic fluid within the bore of the extendable member.

17. The implant of claim 5 including a plurality of extendable support members cooperating with the base.

18. The implant of claim 17 wherein at least two of the extendable support members are adapted to be independently extended.

19. The implant of claim 5 wherein a plurality of support members cooperate with the base and are coupled to the pressure applying member.

20. The implant of claim 19 wherein at least two of the support members have bores and have extendable fixation elements disposed within the bores.

21. A method of treating a patient'"'"'s vertebral structure, comprising:

a. providing a spinal implant having

i. a first surface for engaging an end plate of a first adjacent vertebral body;

ii. a second surface for engaging an end plate of a second adjacent vertebral body;

iii. at least one extendable fixation element having a distal tip, a contracted configuration within the implant to facilitate deployment of the implant between the first and second vertebral bodies and an extended configuration to extend the distal tip beyond the second surface to engage an end plate of the second adjacent vertebral body and to fix the implant within the space between the first and second adjacent vertebral bodies.

b. inserting the spinal implant into a space between two vertebral bodies with the at least one extendable fixation element in the contracted configuration; and

c. extending the fixation element into the extended configuration until the distal tip engages an end of an adjacent vertebral body so as to fix the implant within the space between two vertebral bodies.

22. The method of claim 21 wherein the second surface of the implant has a passageway and the fixation element extends through the passageway upon extension to the extended configuration.

23. The method of claim 21 wherein the implant has at least one extendable support member connected between the first and second pressure applying surfaces to expand the implant within the space between two adjacent vertebral bodies.

24. The method of claim 23 wherein the at least one extendable support member has a bore which receives a fixation element which is extended upon extension of the support member.