Facet joint replacement instruments and methods
A facet joint replacement system includes an inferior implant with an inferior articular surface, a superior implant with a superior articular surface, and an optional crossbar. The inferior implant and the superior implant are each polyaxially adjustably connected to fixation elements which anchor the implants to adjacent vertebrae. The optional crossbar may be polyaxially adjustably connected to bilateral implants. The system components may be provided in kits which provide components of various sizes and shapes. A set of surgical instruments may facilitate implantation of the facet joint replacement system by providing tools for bone preparation, trialing, implant insertion, implant alignment, and lock-out of modular interconnections.
1. A facet joint replacement device, said device comprising:
a superior facet joint replacement component configured to replace a natural superior articular facet on a first vertebra of a spine;
an inferior facet joint replacement component, said inferior facet joint replacement component comprising a first coupling portion configured to engage a complementary first coupling portion of the superior component to couple the inferior component to the superior component in a predetermined orientation, wherein the first coupling portion of the inferior component comprises a clip having a pair of pins separated from a pair of prongs,
wherein the pair of pins are shaped to engage the superior facet joint replacement component and the pair of prongs are shaped to engage the inferior facet joint replacement component, and
wherein the pair of pins are cylindrical and have a constant diameter over their entire length and the pair of prongs are configured as flanges, correspond to a gripping feature on the inferior facet joint replacement component, and are separated by a slot substantially centered between the pair of prongs to enable the pair of prongs to independently move with respect to each other.
2. The device of claim 1 , wherein, in the predetermined orientation, a complementary surface of the inferior component is in a fixed alignment with an articular surface of the superior component.
3. The device of claim 2 , wherein the complementary surface of the inferior component comprises an articular surface of an inferior facet joint replacement implant.
4. The device of claim 2 , wherein the complementary surface of the inferior component comprises a mock articular surface of an inferior facet joint replacement implant trial.
5. The device of claim 1 , wherein the inferior component is configured to be provisionally coupled to the superior component during at least a portion of a facet joint replacement surgical procedure.
6. The device of claim 1 , wherein the inferior component is configured to engage an inserter tool.
7. The device of claim 6 , wherein the inserter tool is configured to move from an unlocked configuration, in which the inferior component and the inserter tool are separable, to a locked configuration, in which the inferior component and the inserter tool are inseparable.
8. The device of claim 6 , wherein the inserter tool comprises a flexible shaft configured to avoid obstacles in the vicinity of the shaft.
9. The device of claim 1 , wherein the pair of pins of the inferior component comprises two parallel pins and the first coupling portion of the superior component comprises two parallel holes sized and positioned to slidingly receive the pins.
10. The device of claim 1 , wherein the inferior component comprises:
an inferior facet joint replacement implant comprising an articular surface and wherein the clip is removable.
11. The device of claim 10 , comprising engaging the prongs of the clip with the gripping feature of the inferior component to couple the clip to the inferior component in a fixed orientation before coupling the inferior component to an inserter tool.
12. The device of claim 10 , wherein the inferior component is configured to be able to couple to an inserter tool by engaging a third coupling portion of the clip with a complementary third coupling portion of the inserter tool to couple the inferior component to the inserter tool in a set orientation.
13. The device of claim 1 , wherein the inferior component comprises an inferior facet joint replacement implant trial comprising a mock articular surface and the first coupling portion.
14. A facet joint replacement device, said device comprising:
a superior facet joint replacement component configured to replace a natural superior articular facet on a first vertebra of a spine;
an inferior facet joint replacement component comprising a first coupling portion configured to engage a complementary first coupling portion of the superior component to couple the inferior component to the superior component in a predetermined orientation,
wherein the first coupling portion of the inferior component comprises a clip having a first slot and a pair of prongs on one side of the first slot and a pair of pins on another side of the first slot,
wherein the pair of pins are shaped to engage the superior facet joint replacement component and the pair of prongs are shaped to engage the inferior facet joint replacement component, and
wherein the pair of pins are cylindrical and have a constant diameter over their entire length and the pair of prongs are configured as flanges, correspond to a gripping feature on the inferior facet joint replacement component, and are separated by a second slot substantially centered between the pair of prongs to enable the pair of prongs to independently move with respect to each other.
15. The device of claim 14 , wherein, in the predetermined orientation, an articular surface of the inferior component is in a fixed alignment with a complementary articular surface of the superior component.
16. The device of claim 14 , wherein the clip is removable.
17. The device of claim 14 , wherein the inferior component is configured to couple with an inserter tool by engaging the prongs of the clip with the gripping feature of the inferior component to couple the clip to the inferior component in a fixed orientation before engaging a third coupling portion of the clip with a complementary third coupling portion of the inserter tool to couple the inferior component to the inserter tool in a set orientation.
18. A facet joint replacement device, said device comprising:
an inferior trial comprising a first coupling portion configured to engage a complementary first coupling portion of a superior implant to couple the inferior trial to the superior implant in a predetermined orientation,
wherein the first coupling portion of the inferior trial comprises a clip having a pair of prongs separated from a pair of pins,
wherein the pair of pins are shaped to engage the superior implant and the pair of prongs are shaped to engage the inferior trail, and
wherein the pair of pins are cylindrical and have a constant diameter over their entire length and the pair of prongs are configured as flanges, correspond to a gripping feature on the inferior trail, are separated by a slot substantially centered between the pair of prongs to enable the pair of prongs to independently move with respect to each other.
19. The device of claim 18 , wherein, in the predetermined orientation, a mock articular surface of the inferior trial is in a fixed alignment with a complementary articular surface of the superior implant, wherein a gap exists between the mock articular surface and the complementary articular surface.
20. The device of claim 18 , wherein the pair of pins are parallel and the first coupling portion of the superior implant comprises two parallel holes sized and positioned to slidingly receive the pins.