Facet arthroplasty devices and methods
View Patent ↗Devices and surgical methods treat various types of adult spinal pathologies, such as degenerative spondylolisthesis, spinal stenosis, degenerative lumbar scoliosis, and kypho-scoliosis. Various types of spinal joint replacement prostheses, surgical procedures for performing spinal joint replacements, and surgical instruments are used to perform the surgical procedures.
1. A prosthesis to replace a cephalad portion of a natural facet joint on a vertebra, the prosthesis comprising:
an artificial facet joint having an artificial bearing surface adapted and configured to replace the cephalad portion of the natural facet joint;
an aperture in the artificial facet joint positioned adjacent to a pedicle;
an aperture in the artificial facet joint positioned adjacent to or near the lamina; and
a fixation element extending at least partially within the aperture in the artificial facet joint element positioned adjacent to or near the lamina, the fixation element being adapted and configured to be inserted into a lamina portion of a vertebra to affix the artificial facet joint element to the vertebra.
2. The prosthesis of claim 1 wherein the artificial facet joint is configured to allow access to a pedicle portion of the vertebra.
3. The prosthesis of claim 1 wherein the artificial facet joint includes a second aperture positioned adjacent or near the lamina.
4. The prosthesis of claim 3 wherein the aperture and the second aperture are on opposite sides of a midline of the vertebra so that a fixation element inserted into the aperture or the second aperture will traverse the midline to affix the artificial facet joint to the lamina.
5. The prosthesis of claim 1 wherein the artificial bearing surface is adapted and configured to be in an anatomically correct position with respect to the vertebra when the prosthesis is affixed to the lamina by the fixation element.
6. The prosthesis of claim 1 wherein the artificial bearing surface is adapted and configured to be in other than an anatomically correct position with respect to the vertebra when the prosthesis is affixed to the lamina by the fixation element.
7. The prosthesis of claim 1 further comprising an attachment element adapted and configured to attach the artificial facet joint to the fixation element.
8. The prosthesis of claim 1 wherein the fixation element comprises an artificial facet joint element attachment end and an insertion tool engagement end, the artificial facet joint attachment end being adapted and configured to lie on one side of the lamina portion and the artificial facet joint attachment end being adapted and configured to lie on another side of the lamina portion.
9. The prosthesis of claim 1 wherein the artificial facet joint is adapted and configured to be disposed between a caudal facet joint bearing surface and a portion of the vertebra.
10. The prosthesis of claim 1 wherein the artificial facet joint comprises a cephalad bearing surface having a substantially convex shape.
11. The prosthesis of claim 1 wherein the artificial facet joint artificial bearing surface is adapted and configured to replace a removed cephalad portion of the natural facet joint.
12. A prosthesis to replace a cephalad portion of a natural facet joint on a vertebra, the prosthesis comprising:
an artificial facet joint element with a bearing surface adapted and configured to replace the cephalad portion of the natural facet joint;
a first fixation hole in the artificial facet joint element positioned to allow access medial of a pedicle on the vertebra and adapted and configured to allow fixation of the artificial facet joint element to the vertebra;
a fixation element adapted and configured to affix the artificial facet joint element to the vertebra using the first fixation hole; and
a second fixation hole in the artificial facet joint element adapted and configured to allow access to a pedicle portion of the vertebra.
13. The prosthesis of claim 12 wherein the artificial facet joint element comprises a cephalad bearing surface adapted and configured to be in an anatomically correct position with respect to the vertebra when the prosthesis is affixed to the vertebra by the fixation element.
14. The prosthesis of claim 12 wherein the artificial facet joint element comprises a cephalad bearing surface adapted and configured to be in other than an anatomically correct position with respect to the vertebra when the prosthesis is affixed to the vertebra by the fixation element.
15. The prosthesis of claim 12 further comprising an attachment element adapted and configured to attach the artificial facet joint element to the fixation element.
16. The prosthesis of claim 12 wherein the fixation element comprises an artificial facet joint element attachment end and an insertion tool engagement end, the artificial facet joint attachment end being adapted and configured to lie on one side of a lamina portion of the vertebra and the artificial facet joint attachment end being adapted and configured to lie on another side of the lamina portion.
17. The prosthesis of claim 12 wherein the artificial facet joint element is adapted and configured to be disposed between a caudal facet joint bearing surface and a portion of the vertebra.
18. The prosthesis of claim 12 wherein the artificial facet joint element comprises a cephalad bearing surface having a substantially convex shape.
19. The prosthesis of claim 12 wherein the artificial facet joint element bearing surface is adapted and configured to replace a removed cephalad portion of the natural facet joint.
20. A prosthesis to replace a caudal portion of a natural facet joint on a vertebra, the prosthesis comprising:
an artificial facet joint element comprising a vertebra contacting surface and a caudal bearing surface, the caudal bearing surface being adapted and configured to replace the caudal portion of a natural facet joint and to be substantially entirely posterior of a contact portion of the vertebra when the vertebra contacting surface contacts the contact portion;
an aperture through the artificial facet joint and configured to provide access to the pedicle of the vertebra;
an aperture through the artificial facet joint element adapted and configured to provide midline access to the lamina of the vertebra when the vertebra contacting surface contacts the contact portion; and
a fixation element adapted and configured to be inserted through the aperture configured to provide midline access to the lamina and into the vertebra to affix the prosthesis to the vertebra.
21. The prosthesis of claim 20 wherein the caudal bearing surface is further adapted and configured to be in an anatomically correct position with respect to the vertebra when the prosthesis is affixed to the vertebra by the fixation element.
22. The prosthesis of claim 20 wherein the caudal bearing surface is further adapted and configured to be in an other than anatomically correct position with respect to the vertebra when the prosthesis is affixed to the vertebra by the fixation element.
23. The prosthesis of claim 20 further comprising an attachment element adapted and configured to attach the artificial facet joint element to the fixation element.
24. The prosthesis of claim 20 wherein the caudal bearing surface has a substantially concave shape.
25. The prosthesis of claim 20 wherein the artificial facet joint element caudal bearing surface is adapted and configured to replace a removed caudal portion of the natural facet joint.
26. A prosthesis to replace a caudal portion and a cephalad portion of a natural facet joint of cephalad and caudal vertebrae, the prosthesis comprising:
an artificial cephalad facet joint element adapted and configured to replace the cephalad portion of the natural facet joint, the artificial cephalad facet joint element comprising a cephalad bearing surface;
an aperture formed in the artificial cephalad facet joint element adapted and configured to allow access to a pedicle portion of the cephalad vertebra when the artificial cephalad facet joint element is position to replace the removed cephalad portion of the natural facet joint;
an aperture formed in the artificial cephalad facet joint element adapted and configured to allow access to a lamina portion of the cephalad vertebra when the artificial cephalad facet joint element is positioned to replace the removed cephalad portion of the natural facet joint;
a cephalad fixation element adapted and configured to be inserted through the aperture formed in the artificial cephalad facet joint element that is conflaured to allow access to the lamina portion of the cephalad vertebra and into that lamina portion to affix the artificial cephalad facet joint element to the cephalad vertebra; and
an artificial caudal facet joint element adapted and configured to replace the caudal portion of the natural facet joint, the artificial caudal facet joint element comprising a caudal bearing surface adapted and configured to mate with the cephalad bearing surface.
27. The prosthesis of claim 26 wherein the aperture in the artificial cephalad facet joint element that is adapted and configured to allow access to a lamina portion of the cephalad vertebra is positioned such that the cephalad fixation element may be inserted through the aperture and the lamina portion of the vertebra to affix the artificial cephalad facet joint element to the vertebra without blocking access to a pedicle portion of the vertebra.
28. The prosthesis of claim 26 further comprising: another aperture formed in the artificial cephalad facet joint element wherein the lamina portion of the cephalad vertebra is a first lamina portion of a cephalad vertebra, and the another aperture is adapted and configured to provide access through a second lamina portion of a cephalad vertebra; and a second cephalad fixation element adapted and configured to be inserted through the another aperture and the second lamina portion of the cephalad vertebra to affix the artificial cephalad facet joint element to the vertebra.
29. The prosthesis of claim 28 wherein first and second lamina portions of the cephalad vertebra are on opposite sides of a midline of the vertebra, the first or the second cephalad fixation elements traverse the midline to affix the artificial cephalad facet joint element to the vertebra.
30. The prosthesis of claim 26 wherein the artificial cephalad facet joint element is adapted and configured to be disposed between the caudal facet joint bearing surface and a portion of the cephalad vertebra.
31. The prosthesis of claim 26 further comprising an aperture in the caudal fixation element adapted and configured to provide access to a lamina portion of the caudal vertebra; and a caudal fixation element adapted and configured to pass through the aperture in the caudal fixation element to affix the artificial caudal facet joint element to the caudal vertebra.
32. The prosthesis of claim 26 wherein the cephalad bearing surface and the caudal bearing surface are adapted and configured to be in anatomically correct positions with respect to the cephalad and caudal vertebrae when the prosthesis is affixed to the cephalad and caudal vertebrae, respectively.
33. The prosthesis of claim 26 wherein the cephalad bearing surface and the caudal bearing surface are adapted and configured to be in other than anatomically correct positions with respect to the cephalad and caudal vertebrae when the prosthesis is affixed to the cephalad and caudal vertebrae, respectively.
34. The prosthesis of claim 26 wherein cephalad bearing surface and the caudal bearing surface each has a width along its respective transverse axis, the cephalad bearing surface width being shorter than the caudal bearing surface width.
35. The prosthesis of claim 26 wherein the cephalad bearing surface has a substantially convex shape and the caudal bearing surface has a substantially concave shape.
36. The prosthesis of claim 26 wherein the artificial caudal facet joint element further comprises a vertebra contacting surface, the entire caudal bearing surface being adapted and configured to be posterior of a contact portion of the caudal vertebra when the vertebra contacting surface contacts the contact portion.