Spinal facet implants with mating articulating bearing surface and methods of use
View Patent ↗Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.
1. An implantable system comprising:
an inferior prosthesis configured to replicate a movement of an inferior facet joint, the inferior prosthesis including a first articulating surface;
a superior prosthesis configured to replicate a movement of a superior facet joint, the superior prosthesis including a second articulating surface that engages the first articulating surface;
a ball and socket joint for providing the inferior prosthesis with motion in an anterior/posterior direction; and
at least one turnbuckle that compresses a first flange and a second flange around the ball and socket joint to fix displacement of the ball and socket joint.
2. The system of claim 1 , wherein the articulating surface of the inferior prosthesis is convex.
3. The system of claim 1 , wherein the articulating surface of the superior prosthesis is concave.
4. The system of claim 1 , wherein the ball and socket joint comprises a ball-shaped member having divots formed thereon.
5. The system of claim 1 , wherein the first articulating surface is formed of polymeric material.
6. The system of claim 1 , wherein the first articulating surface is formed of a polymeric material attached to a metal substrate.