Prosthetic disc and vertebral body replacement device having pyrolytic carbon bearing members

Abstract

A spinal motion device for implanting in the spine as a replacement for the natural disc, to permit motion between adjacent vertebral bodies or as a vertebral body replacement that permits motion at its ends. The spinal motion device comprises a composite structure formed by a body having at least one bearing member, made from a biocompatible material such as pyrolytic carbon, attached to a support surface thereof.

What is claimed is:  
     
         1 . A spinal motion device comprising: 
 a body having opposing first and second surfaces; and    at least a first bearing member attached to the first surface.    
     
     
         2 . The device of  claim 1 , wherein the body is porous.  
     
     
         3 . The device according to  claim 1 , wherein the at least first bearing member is made from pyrolytic carbon.  
     
     
         4 . The device of  claim 1 , wherein the support surfaces are separated by side surfaces which extend between a posterior end of the body and an anterior end of the body.  
     
     
         5 . The device according to  claim 1 , wherein the support surfaces taper posteriorly such that the body has a thickness that decreases from the anterior end to the posterior end.  
     
     
         6 . The device according to  claim 1 , wherein the at least first bearing member defines a convex bearing surface.  
     
     
         7 . The device according to  claim 1 , wherein the at least first bearing member defines a bearing surface that convexly curves in an elliptical manner.  
     
     
         8 . The device according to  claim 1 , further comprising a second bearing member attached to the second surface.  
     
     
         9 . The device according to  claim 8 , wherein the bearing members are made from pyrolytic carbon.  
     
     
         10 . The device according to  claim 8 , wherein the first bearing member defines a convex bearing surface.  
     
     
         11 . The device according to  claim 10 , wherein the second bearing member defines a concave bearing surface.  
     
     
         12 . The device according to  claim 1 , further comprising a post and hole arrangement associated with the at least first bearing member and the body for attaching the bearing member to the first surface of the body.  
     
     
         13 . The device according to  claim 12 , further comprising a grout for aiding the post and hole arrangement in attaching the at least first bearing member to the first surface of the body.  
     
     
         14 . The device according to  claim 13 , wherein the grout comprises one of a cement and a polymer.  
     
     
         15 . The device according to  claim 14 , wherein the polymer is selected from the group consisting of polyethylene, urethane, silicone, siloxane-urethane, polyurethane, polycarbonate urethane, and hydrogel.  
     
     
         16 . The device according to  claim 14 , wherein the polymer is resilient.  
     
     
         17 . The device according to  claim 1 , further comprising a grout for attaching the at least first bearing member to the first surface of the body.  
     
     
         18 . The device according to  claim 17 , wherein the grout comprises one of a cement and a polymer.  
     
     
         19 . The device according to  claim 18 , wherein the polymer is selected from the group consisting of polyethylene, urethane, silicone, siloxane-urethane, polyurethane, polycarbonate urethane, and hydrogel.  
     
     
         20 . The device according to  claim 18 , wherein the polymer is resilient.  
     
     
         21 . The device according to  claim 1 , wherein the device is useable as a disc replacement or as a vertebral body replacement.  
     
     
         22 . The device according to  claim 1 , wherein the at least first bearing member defines a concave bearing surface.  
     
     
         23 . A spinal motion device for implanting in a spine, the device comprising: 
 a porous body having opposing first and second surfaces;    a first bearing member made from a biocompatible material selected from the group consisting of biocompatible metals, metal alloys, ceramics, polymers, pyrolytic carbon and combinations thereof; and    attaching means for attaching the first bearing member to the first surface.    
     
     
         24 . The device according to  claim 23 , further comprising: 
 a second bearing member made from a biocompatible material selected from the group consisting of biocompatible metals, metal alloys, ceramics, polymers, pyrolytic carbon, and combinations thereof; and    attaching means for attaching the second bearing member to the second surface.