Facet joint prosthesis

Abstract

A facet joint prosthesis comprising an inferior prosthetic portion and a superior prosthetic portion is disclosed. Inferior prosthetic portion includes a first anchor member and a first articulating member and superior prosthetic portion includes a second anchor member and a second articulating member. The first articulating member comprises a support portion and first articulating surface and the second articulating member comprises a second articulating surface, and first and second articulating surfaces are configured and dimensioned to contact or engage one another. A flexible element is positioned between the support portion and the first articulating surface.

1 . A facet joint prosthesis, comprising: 
 an inferior prosthetic portion comprising a first anchor member and a first articulating member;    a superior prosthetic portion comprising a second anchor member and a second articulating member;    wherein the first and second anchor members comprise screws,    wherein the first articulating member comprises a support portion fixably connected to the first anchor member,    wherein the first articulating member comprises first articulating surface, and the second articulating member comprises second articulating surface, the first and second articulating surfaces configured and dimensioned to contact or engage one another, and    a flexible element positioned between the support portion and the first articulating surface.    
   
   
       2 . The prosthesis of  claim 1 , wherein the first articulating surface is generally convex and the second articulating surface is generally concave.  
   
   
       3 . The prosthesis of  claim 1 , wherein the second articulating member comprises a connector portion fixably connectable to the second anchor member to allow lockable positioning of the second articulating surface.  
   
   
       4 . The prosthesis of  claim 1 , wherein the support portion comprises a rod.  
   
   
       5 . The prosthesis of  claim 1 , wherein the flexible element comprises a helical slit formed in the support portion.  
   
   
       6 . The prosthesis of  claim 1 , wherein the flexible element comprises a spring.  
   
   
       7 . The prosthesis of  claim 1 , wherein the flexible element comprises an elastomeric material.  
   
   
       8 . The prosthesis of  claim 1 , wherein the inferior and superior portions are made from titanium.  
   
   
       9 . The prosthesis of  claim 1 , wherein the first and second anchor members comprise a polyaxial screw.  
   
   
       10 . The prosthesis of  claim 3 , wherein the second articulating portion comprises a screw cap configured and dimensioned to mate with a top of the second anchor member.  
   
   
       11 . The prosthesis of  claim 1 , wherein the flexible element is positioned between the first and second articulating surfaces.  
   
   
       12 . The prosthesis of  claim 11 , wherein the flexible element comprises an elastomer material.  
   
   
       13 . The prosthesis of  claim 11 , wherein the flexible element encapsulates the first and second articulating surfaces.  
   
   
       14 . The prosthesis of  claim 13 , wherein the flexible element comprises a sleeve made from a polyurethane material.  
   
   
       15 . The prosthesis of  claim 1 , wherein the first articulating member comprises a bilateral member having a pair of generally convex bearing surfaces, and 
 wherein the second articulating member comprises a pair of articulating elements, each articulating element comprising a generally concave surface configured and dimensioned to contact or engage one of the pair of generally convex bearing surfaces of the bilateral member.    
   
   
       16 . A facet joint prosthesis, comprising: 
 a first prosthetic portion comprising a first anchor member and a first articulating member;    a second prosthetic portion comprising a second anchor member and a second articulating member; and    a flexible element interconnected between the first and second articulating members;    wherein the first and second anchor members comprise screws,    wherein the first articulating member comprises a first support portion fixably connected to the first anchor member and the second articulating member comprises a second support portion fixably connected to the second anchor member,    wherein the first articulating member comprises first articulating surface, and the second articulating member comprises second articulating surface.    
   
   
       17 . The prosthesis of  claim 16 , wherein the first and second articulating surfaces are generally spherical and the flexible element comprises a sleeve having at least two generally spherical openings, each opening configured and dimensioned to receive one of the first and second articulating surfaces.  
   
   
       18 . The prosthesis of  claim 17 , wherein the sleeve is made from an elastomer material.  
   
   
       19 . The prosthesis of  claim 16 , wherein the flexible element encapsulates the first and second articulating surfaces.  
   
   
       20 . The prosthesis of  claim 19 , wherein the first and second articulating members are made from a titanium material and the flexible element is made from an elastomeric material.