Spinal facet implants with mating articulating bearing surface and methods of use

Abstract

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.

What is claimed is: 
     
         1 . A surgical method comprising:
 providing a prosthesis, wherein the prosthesis comprises a fixation element and an articulating component attached to the fixation element, wherein the articulating component comprises an articulating surface; and   inserting the prosthesis via the fixation element into a bone member.   
     
     
         2 . The method of  claim 1 , wherein the prosthesis further comprises a flange between the fixation element and the articulating component. 
     
     
         3 . The method of  claim 2 , wherein the flange comprises an opening that surrounds the fixation element. 
     
     
         4 . The method of  claim 2 , wherein the flange is attached to the fixation element via a castle nut. 
     
     
         5 . The method of  claim 1 , wherein the articulating component is in the shape of a blade or wing ear. 
     
     
         6 . The method of  claim 1 , wherein the articulating surface has a concave shape. 
     
     
         7 . The method of  claim 1 , wherein the articulating surface curves from an orientation generally perpendicular to the flange towards an orientation generally parallel to the flange from a distal end thereof to a proximal end thereof. 
     
     
         8 . The method of  claim 1 , wherein a proximal portion of the fixation element includes a drive feature. 
     
     
         9 . The method of  claim 8 , wherein the drive feature comprises an internal hex. 
     
     
         10 . A surgical method comprising:
 resecting a portion of a bone member;   providing a prosthesis, wherein the prosthesis comprises a fixation element and an articulating component attached to the fixation element, wherein the articulating component comprises an articulating surface;   inserting the prosthesis via the fixation element into the bone member.   
     
     
         11 . The method of  claim 10 , wherein the bone member comprises a pedicle. 
     
     
         12 . The method of  claim 10 , wherein the prosthesis further comprises a coupling portion attached to the articulating component. 
     
     
         13 . The method of  claim 12 , wherein the coupling portion comprises a bone engaging surface that engages the resected portion of the bone member. 
     
     
         14 . The method of  claim 13 , wherein the coupling portion comprises a generally semispherical surface. 
     
     
         15 . The method of  claim 10 , wherein the prosthesis further comprises a flange with an opening that surrounds the fixation element. 
     
     
         16 . The method of  claim 10 , wherein the fixation element comprises a drive feature in the form of a hex socket. 
     
     
         17 . The method of  claim 10 , wherein the articulating surface is concave. 
     
     
         18 . A surgical method comprising:
 providing a prosthesis comprising:
 a fixation element implantable into a vertebra; 
 a coupling portion shaped to be coupled to the fixation element, the coupling potion having a bone engaging surface positioned to abut the vertebra; and 
 an articulating surface attached to the coupling portion; and 
   inserting the prosthesis into a bone member.   
     
     
         19 . The method of  claim 18 , wherein the prosthesis is inserted into a pedicle. 
     
     
         20 . The method of  claim 18 , wherein the bone engaging surface is concave.