System and Method for Multiple Level Facet joint Arthroplasty and Fusion

Abstract

Facet joint replacement implants may be designed for use on multiple adjacent vertebral levels. Each superior implant may have a substantially semispherical concave surface, and each inferior implant may have a cooperating semispherical convex surface that is deformable to enable it to be pressed into the superior implant concave surface to fix the relative orientations of the superior and inferior implants. Thus, the inferior implant may be attached to the same pedicle as the superior implant, but may also be oriented independently of the superior implant and then fixed in position. Similar mounting structures may be used to attach one or more fusion implants to a level adjacent to that of a facet joint replacement implant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed with reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope.

FIG. 1 is a perspective view of a system according to one embodiment of the invention, in which multiple level facet joint replacement may be carried out with adjacent level fusion.

FIG. 2 is an exploded, perspective view of the caudal facet joint assembly, fixation members, and locking assemblies of the system of FIG. 1.

FIG. 3 is an exploded, perspective view of the caudal fusion assembly, fixation members, and yoke assemblies of the system of FIG. 1.

FIG. 4 is an exploded, perspective view of the cephalad fusion assembly, fixation members, and yoke assemblies of the system of FIG. 1.

FIG. 5 is a perspective view of a system according to one alternative embodiment of the invention, in which multiple level facet joint replacement may be carried out without adjacent level fusion.

FIG. 6 is a perspective view of one of the engagement members of the system of FIG. 5.

FIG. 7 is a perspective view of one of the in-growth cups of the system of FIG. 5.

FIG. 8 is a perspective view of a portion of a spine to which the system of FIG. 1 or the system of FIG. 5 may be secured to provide multiple level facet joint replacement with or without adjacent level fusion.

FIG. 9 is a perspective view of the portion of the spine of FIG. 8 after resection of some of the natural articular surfaces of the vertebrae.

FIG. 10 is a perspective view of the portion of the spine of FIG. 8 after implantation of guide wires in the pedicles of some of the vertebrae.

FIG. 11 is a perspective view of the portion of the spine of FIG. 8 after reaming of the pedicle saddle points to provide semispherical resections.

FIG. 12 is a perspective view of the portion of the spine of FIG. 8 with a frame registered on the third vertebra to facilitate formation of shaped resections on the saddle points of the second vertebra.

FIG. 13 is a perspective view of the portion of the spine of FIG. 8 after attachment of the caudal fusion assembly and the superior prostheses of the caudal facet joint assembly of the system of FIG. 1 to the portion of the spine.

FIG. 14 is a perspective view of the portion of the spine of FIG. 8 with the frame registered on the fourth vertebra to facilitate formation of shaped resections on the saddle points of the third vertebra.

FIG. 15 is a perspective view of the portion of the spine of FIG. 8 after further attachment of the inferior prostheses of the caudal facet joint assembly and the superior prostheses of the cephalad facet joint assembly of the system of FIG. 1 to the portion of the spine.

FIG. 16 is a perspective view of the portion of the spine of FIG. 8 with the frame registered on the fifth vertebra to facilitate formation of shaped resections on the saddle points of the fourth vertebra.

FIG. 17 is a perspective view of the portion of the spine of FIG. 8 after further attachment of the inferior prostheses of the cephalad facet joint assembly of FIG. 1 and a cephalad fusion assembly to the portion of the spine.

FIG. 18 is a perspective view of the portion of the spine of FIG. 8 with the system of FIG. 5 attached thereto instead of the system of FIG. 17.

Claims

1. A system comprising: a superior articular surface attachable to a first vertebra to articulate with an adjacent inferior articular surface; andan inferior articular surface attachable to the first vertebra, independently of attachment of the superior articular surface to the first vertebra, to articulate with an adjacent superior articular surface;wherein at least one of the superior and inferior articular surfaces is polyaxially adjustably attachable to the first vertebra.

2. The system of claim 1, wherein the superior articular surface is incorporated into a first superior prosthesis and the inferior articular surface is incorporated into a first inferior prosthesis.

3. The system of claim 2, wherein the superior articular surface and the inferior articular surface are both configured to be positioned on a side selected from a right side of the first vertebra, and a left side of the first vertebra.

4. The system of claim 2, further comprising a fixation member implantable in the first vertebra to attach the first superior prosthesis and the first inferior prosthesis to the first vertebra.

5. The system of claim 2, wherein the first superior prosthesis and the first inferior prosthesis are both polyaxially adjustably attachable to the first vertebra.

6. The system of claim 5, wherein the first superior and inferior prostheses are configured to be assembled with the vertebra such that, prior to complete attachment of the first superior and inferior prostheses to the first vertebra, the first superior and inferior prostheses are both polyaxially rotatable with respect to the first vertebra about a single center of rotation.

7. The system of claim 6, wherein each of the first superior and inferior prostheses comprises a mounting portion comprising a semispherical surface, wherein the semispherical surfaces of the first superior and inferior prostheses are shaped to nest against each other to provide the single center of rotation.

8. The system of claim 7, wherein at least one of the semispherical surfaces of the first superior and inferior prostheses comprises a feature configured to facilitate deformation of the semispherical surface as the mounting portions are attached to the first vertebra.

9. The system of claim 2, further comprising a second superior prosthesis and a second inferior prosthesis, wherein the first and second superior and inferior prostheses are configured to cooperate to provide left and right superior articular surfaces and left and right inferior articular surfaces on the first vertebra.

10. The system of claim 9, further comprising a crosslink attachable to the first and second inferior prostheses to substantially prevent relative motion between the first and second inferior prostheses.

11. A system comprising: a second prosthesis attachable to a first vertebra and a second vertebra of a spine to substantially prevent relative motion between the first and second vertebrae; anda first prosthesis attachable to the first vertebra independently of prevention of relative motion between the first and second vertebrae via the second prosthesis, the first prosthesis comprising a first articular surface shaped to articulate with a second articular surface on a third vertebra of the spine.

12. The system of claim 11, wherein the first prosthesis is further attachable to the first vertebra independently of attachment of the second prosthesis to the first vertebra.

13. The system of claim 11, further comprising a fixation member implantable in the first vertebra to attach the first prosthesis and the second prosthesis to the first vertebra.

14. The system of claim 13, wherein the first prosthesis is polyaxially adjustably attachable to the first vertebra, wherein the second prosthesis comprises: a rod configured to be attached to the first and second vertebrae; anda yoke configured to receive the rod, wherein the yoke is polyaxially adjustably attachable to one of the first and second vertebrae.

15. The system of claim 14, wherein the yoke is polyaxially adjustably attachable to the first vertebra.

16. The system of claim 11, wherein at least one of the first and second prostheses is polyaxially adjustably attachable to the first vertebra.

17. The system of claim 16, wherein the first and second prostheses are configured to be assembled with the first vertebra such that, prior to complete attachment of the first and second prostheses to the first vertebra, the first and second prostheses are both polyaxially rotatable with respect to the first vertebra about a single center of rotation.

18. The system of claim 17, wherein each of the first and second prostheses comprises a mounting portion comprising a semispherical surface, wherein the semispherical surfaces of the first and second prostheses are shaped to nest against each other to provide the single center of rotation.

19. The system of claim 18, wherein at least one of the semispherical surfaces of the first and second prostheses comprises a feature configured to facilitate deformation of the semispherical surface as the mounting portions are attached to the first vertebra.

20. The system of claim 11, further comprising a third prosthesis attachable to the first and second vertebrae to cooperate with the second prosthesis to substantially prevent relative motion between the first and second vertebrae; and a crosslink attachable to the second and third prostheses to substantially prevent relative motion between the second and third prostheses.

21. A method comprising: polyaxially adjusting an orientation of at least one of a superior articular surface and an inferior articular surface to provide a selected orientation with respect to a first vertebra;attaching the superior articular surface to the first vertebra such that the superior articular surface is positioned to articulate with an adjacent inferior articular surface; andattaching the inferior articular surface to the first vertebra, independently of attachment of the superior articular surface to the first vertebra, such that the inferior articular surface is positioned to articulate with an adjacent superior articular surface;wherein attachment of the at least one of the superior and inferior articular surfaces substantially preserves the selected orientation.

22. The method of claim 21, wherein the superior articular surface is incorporated into a first superior prosthesis and the inferior articular surface is incorporated into a first inferior prosthesis, wherein attaching the superior articular surface to the first vertebra comprises attaching the first superior prosthesis to the first vertebra; wherein attaching the inferior articular surface to the first vertebra comprises attaching the first inferior prosthesis to the first vertebra.

23. The method of claim 22, further comprising positioning the superior and inferior articular surfaces on a side selected from a right side of the first vertebra, and a left side of the first vertebra, prior to attachment of the superior and inferior articular surfaces to the first vertebra.

24. The method of claim 23, further comprising implanting a fixation member in the first vertebra, wherein attaching the first superior and inferior prostheses to the first vertebra comprises retaining the first superior and inferior prostheses with the fixation member.

25. The method of claim 22, wherein polyaxially adjusting the orientation of at least one of the superior articular surfaces comprises polyaxially adjusting orientations of both of the superior and inferior articular surfaces to provide selected orientations of the superior and inferior articular surfaces with respect to the first vertebra; wherein attaching the superior and inferior articular surfaces to the first vertebra comprises substantially preserving the selected orientations.

26. The method of claim 25, wherein polyaxially adjusting orientations of both of the superior and inferior articular surfaces comprises polyaxially rotating the first superior and inferior prostheses with respect to the first vertebra about a single center of rotation.

27. The method of claim 26, wherein each of the first superior and inferior prostheses comprises a mounting portion comprising a semispherical surface, the method further comprising nesting the semispherical surfaces of the first superior and inferior prostheses against each other to provide the single center of rotation.

28. The method of claim 27, wherein at least one of the semispherical surfaces of the first superior and inferior prostheses comprises a feature, wherein attaching the first superior and inferior prostheses to the first vertebra comprises deforming the at least one semispherical surface, wherein deformation of the semispherical surface is enhanced by the feature.

29. The method of claim 22, further comprising: Attaching a second superior prosthesis to the first vertebra; andAttaching a second inferior prosthesis to the first vertebra such that the first and second superior and inferior prostheses are configured to cooperate to provide left and right superior articular surfaces and left and right inferior articular surfaces on the first vertebra.

30. The method of claim 29, further comprising attaching a crosslink to the first and second inferior prostheses to substantially prevent relative motion between the first and second inferior prostheses.

31. A method comprising: attaching a second prosthesis to a first vertebra and a second vertebra of a spine to substantially prevent motion between the first and second vertebrae; andattaching a first prosthesis to the first vertebra independently of prevention of relative motion between the first and second vertebrae via the second prosthesis, the first prosthesis comprising a first articular surface shaped to articulate with a second articular surface on a third vertebra of the spine.

32. The method of claim 31, wherein attaching the first prosthesis to the first vertebra further comprises attaching the first prosthesis to the first vertebra independently of attachment of the second prosthesis to the first vertebra

33. The method of claim 31, further comprising implanting a fixation member in the first vertebra, wherein attaching the first and second prostheses to the first vertebra comprises retaining the first and second prostheses with the fixation member.

34. The method of claim 33, further comprising: polyaxially adjusting orientations the first prosthesis and a yoke of the second prosthesis to provide independently selected orientations of the first prosthesis and the yoke;receiving a rod with the yoke; andattaching the yoke to one of the first vertebra and the second vertebra.

35. The method of claim 34, wherein attaching the yoke to one of the first vertebra and the third vertebra comprises attaching the yoke to the first vertebra.

36. The method of claim 31, further comprising polyaxially adjusting orientations of the first and second prostheses to provide selected orientations of the first and second prostheses with respect to the first vertebra; wherein attaching the first and second prostheses to the first vertebra comprises substantially preserving the selected orientations.

37. The method of claim 36, wherein polyaxially adjusting orientations of the first and second prostheses comprises polyaxially rotating the first and second prostheses about a single center of rotation.

38. The method of claim 37, wherein each of the first and second prostheses comprises a mounting portion comprising a semispherical surface, the method further comprising nesting the semispherical surfaces of the first and second prostheses against each other to provide the single center of rotation.

39. The method of claim 38, wherein at least one of the semispherical surfaces of the first and second prostheses comprises a feature, wherein attaching the first and second prostheses to the first vertebra comprises deforming the at least one semispherical surface, wherein deformation of the semispherical surface is enhanced by the feature.

40. The method of claim 31, further comprising: attaching a third prosthesis to the first and second vertebrae such that the third prosthesis cooperates with the second prosthesis to substantially prevent relative motion between the first and second vertebrae; andattaching a crosslink to the second and third prostheses to substantially prevent relative motion between the second and third prostheses.