Inter-cervical facet implant and method

• US 7,776,090 B2
• Filed: 02/08/2005
• Issued: 08/17/2010
• Est. Priority Date: 12/13/2004
• Status: Active Grant

• Current Assignee: Kyphon SARL (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Flynn, John J., Mitchell, Steven T., Zucherman, James F., Winslow, Charles J., Hsu, Ken Y., Yerby, Scott A.
• Primary Examiner(s): Barrett; Thomas C
• Assistant Examiner(s): Araj; Michael J
• Application Number:
  US11/053,735
• Publication Number:
  US 20060149374A1
• Time in Patent Office: 2,016 Days
• Field of Search: 623 1711- 1716, 606/61, 606/86, 606/90, 606246-249, 606/257, 606282-296
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/562 Implants for placement in joint gaps without restricting joint motion, e.g. to reduce arthritic pain
• CPC Class Codes: A61B 17/7007 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit around the screw or hook heads
• CPC Class Codes: A61B 17/701 Longitudinal elements with a non-circular, e.g. rectangular, cross-section A61B17/7005, A61B17/7007 take precedence
• CPC Class Codes: A61B 17/7022 Tethers, i.e. longitudinal elements capable of transmitting tension only, e.g. straps, sutures or cables A61B17/702 takes precedence
• CPC Class Codes: A61B 17/7028 the flexible part being a coil spring
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/7071 Implants for expanding or repairing the vertebral arch or wedged between laminae or pedicles; Tools therefor
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• CPC Class Codes: A61B 2017/8655 with special features for locking in the bone
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/4405 for apophyseal or facet joints, i.e. between adjacent spinous or transverse processes devices implanted between spinous or transverse processes A61B17/7062

Abstract

Systems and method in accordance with the embodiments of the present invention can include an implant for positioning within a cervical facet joint for distracting the cervical spine, thereby increasing the area of the canals and openings through which the spinal cord and nerves must pass, and decreasing pressure on the spinal cord and/or nerve roots. The implant can be inserted laterally or posteriorly.

Claims

1. A facet joint implant adapted to correct spinal stenosis and other ailments of a spine, the implant comprising:

a first facet joint spacer adapted to be positioned within a first facet joint formed by two adjacent spinal vertebrae of a first level of the spine, so as to allow mobility of the first facet joint;

a second facet joint spacer adapted to be positioned within a second facet joint formed by the two adjacent spinal vertebrae of the first level of the spine so as to allow mobility of the second facet joint; and

an elongate collar joining the first facet joint spacer with the second facet joint spacer, the collar having a length sufficient for bridging between the first facet joint and the second facet joint,

wherein the collar further comprises a first bore positioned adjacent to the first facet joint spacer, and a second bore positioned adjacent to the second facet joint spacer, the first bore capable of accepting a first bone screw and the second bore capable of accepting a second bone screw, adapted to secure the implant to the vertebrae;

wherein the implant is adapted to be implanted without resection of bone;

wherein the collar extending medially along a lamina of a posterior arch, wherein the implant is adapted to allow mobility of a first and second cervical facet joints and wherein the implant is adapted to distract the first and second cervical facet joints and to increase the foraminal dimension.

2. The facet joint implant as in claim 1 wherein the collar is connected flexibly with the first facet joint spacer by a first hinge and the collar is connected flexibly with the second facet joint spacer by a second hinge.

3. The facet joint implant as in claim 1 wherein the collar is connected flexibly with the first facet joint spacer and the collar is connected flexibly with the second facet joint spacer.

4. The facet joint implant as in claim 1 wherein the collar can be bent to conform to the anatomy of a patient'"'"'s cervical spine.

5. The facet joint implant as in claim 1 wherein a surface of the first facet joint spacer and a surface of the second facet joint spacer are convex to approximate the shape of a cervical facet joint.

6. The facet joint implant as in claim 1 wherein a superior surface of the first facet joint spacer and a superior surface of the second facet joint spacer are convex to approximate the shape of a cervical facet joint.

7. The facet joint implant as in claim 1 wherein a first distal end of the first facet joint spacer and a second distal end of the second facet joint spacer are tapered to facilitate insertion into a cervical facet joint.

8. The facet joint implant as in claim 1 wherein the first and second facet joint spacers are shaped in order to accommodate the shape of, and distract, facet joints.

9. The cervical facet joint implant as in claim 1 wherein the collar is adapted to be positioned adjacent to a first lateral mass and a second lateral mass, the first and second lateral masses on the same vertebra.

10. The facet joint implant as claim 1 wherein the collar is adapted to be positioned along the lamina of the posterior arch.

11. The facet joint implant as in claim 1 wherein at least one of the first and second facet joint spacers can be comprised of a material that promotes bone ingrowth.

12. The implant of claim 1 wherein the first and second facet joints formed by two adjacent spinal vertebrae of the first level of the spine are substantially aligned on an axial plane extending medially across the two adjacent vertebrae.

13. The implant of claim 1 wherein the first level of the spine comprises a pair of inferior facet joints of one of the two adjacent spinal vertebrae and a pair of superior facet joints of the other of the two adjacent spinal vertebrae such that the pairs of inferior and superior facet joints form the first and second facet joints.

14. A facet joint implant adapted to correct spinal stenosis and other ailments of a spine, the implant comprising:

a first facet joint spacer adapted to be positioned within a first facet joint formed by two adjacent spinal vertebrae of a first level;

a second facet joint spacer adapted to be positioned within a second facet joint formed by the two adjacent spinal vertebrae of the first level; and

a collar joining the first facet joint spacer with the second facet joint spacer,

wherein the collar further comprises a first bore positioned adjacent to the first facet joint spacer, and a second bore positioned adjacent to the second facet joint spacer, the first bore capable of accepting a first bone screw and the second bore capable of accepting a second bone screw, adapted to secure the implant to the vertebrae;

a first locking device positioned to prevent displacement of the first bone screw, and a second locking device positioned to prevent displacement of the second bone screw;

wherein the first level of the spine comprises a pair of inferior facet joints of one of the two adjacent spinal vertebrae and a pair of superior facet joints of the other of the two adjacent spinal vertebrae such that the pairs of the inferior and superior facet joints form the first and second facet joints.

15. The facet joint implant as in claim 14 wherein the collar is connected flexibly with the first facet joint spacer by a first hinge and the collar is connected flexibly with the second facet joint spacer by a second hinge.

16. The facet joint implant as in claim 14 wherein the collar is connected flexibly with the first facet joint spacer and the collar is connected flexibly with the second facet joint spacer.

17. The facet joint implant as in claim 14 wherein a surface of the first facet joint spacer and a surface of the second facet joint spacer are convex to approximate the shape of a cervical facet joint.

18. The facet joint implant as in claim 14 wherein a superior surface of the first facet joint spacer and a superior surface of the second facet joint spacer are convex to approximate the shape of a cervical facet joint.

19. The facet joint implant as in claim 14 wherein a first distal end of the first facet joint spacer and a second distal end of the second facet joint spacer are tapered to facilitate insertion into a cervical facet joint.

20. The implant of claim 14 wherein the collar extending medially along a lamina of the posterior arch, wherein the implant is adapted to allow mobility of the first and second cervical facet joints and wherein the implant is adapted to distract the first and second cervical facet joints and to increase the foraminal dimension.

21. A cervical facet joint implant adapted to correct cervical spinal stenosis and other ailments of a cervical spine, the implant comprising:

a first facet joint spacer adapted to be inserted into a first cervical facet joint, the first facet joint spacer having a first tapered distal end and a first convex surface;

a second facet joint spacer adapted to be inserted into a second cervical facet joint, the second facet joint spacer having a first tapered distal end and a second convex surface;

a collar joining the first facet joint spacer with the second artificial facet joint;

a first hinge connecting the first facet joint spacer with the collar;

a second hinge connecting the second facet joint spacer with the collar, wherein the first hinge and the second hinge enable the collar to be positioned against a vertebra according to a patient'"'"'s cervical spinal anatomy;

a first bore adjacent to the first hinge;

a second bore adjacent to the second hinge, wherein the first bore accepts a first bone screw and the second bore accepts a second bone screw to secure the implant to the vertebra;

a first locking device positioned adjacent to the collar to prevent displacement of the first bone screw; and

a second locking device positioned adjacent to the collar to prevent displacement of the second bone screw.

22. The facet joint implant as in claim 21 wherein at least one of the first and second facet joint spacers can be comprised of a material that promotes bone ingrowth.

23. The facet joint implant as in claim 21 wherein the collar can be bent to conform to the anatomy of a patient'"'"'s cervical spine.

24. The implant of claim 21 wherein the collar extending medially along a lamina of a posterior arch, wherein the implant is adapted to allow mobility of the first and second cervical facet joints and wherein the implant is adapted to distract the first and second cervical facet joints and to increase the foraminal dimension.

25. The implant of claim 21 wherein the collar is connected flexibly with the first facet joint spacer by the first hinge extending completely across a first width of the collar and the collar is connected flexibly with the second facet joint spacer by the second hinge extending completely across a second width of the collar.

26. A facet joint implant adapted to correct spinal stenosis and other ailments of a spine, the implant comprising:

a first facet joint spacer adapted to be positioned within a first facet joint formed by two adjacent spinal vertebrae of a first level of the spine, so as to allow mobility of the first facet joint;

a second facet joint spacer adapted to be positioned within a second facet joint formed by the two adjacent spinal vertebrae of the first level of the spine so as to allow mobility of the second facet joint; and

an elongate collar joining the first facet joint spacer with the second facet joint spacer, the collar having a length sufficient for bridging between the first facet joint and the second facet joint,

wherein the collar is connected flexibly with the first facet joint spacer by a first hinge extending completely across a first width of the collar and the collar is connected flexibly with the second facet joint spacer by a second hinge extending completely across a second width of the collar.

27. The facet joint implant of claim 26 wherein a surface of the first facet joint spacer and a surface of the second facet joint spacer are convex to approximate the shape of a cervical facet joint.

28. The facet joint implant of claim 26 wherein a superior surface of the first facet joint spacer and a superior surface of the second facet joint spacer are convex to approximate the shape of a cervical facet joint.

29. The facet joint implant of claim 26 wherein the first and second facet joints formed by two adjacent spinal vertebrae of the first level of the spine are substantially aligned on an axial plane extending medially across the two adjacent vertebrae.

30. The facet joint implant of claim 26 wherein the first level of the spine comprises a pair of inferior facet joints of one of the two adjacent spinal vertebrae and a pair of superior facet joints of the other of the two adjacent spinal vertebrae such that the pairs of inferior and superior facet joints form the first and second facet joints.