Prostheses, Systems and Methods for Replacement of Natural Facet Joints With Artificial Facet Joint Surfaces

Abstract

Cephalad and caudal vertebral facet joint prostheses and methods of use are provided. The prostheses provide an artificial facet joint structure including an artificial articular configuration unlike the preexisting articular configuration. The radii and material stress values of the prostheses are configured to sustain contact stress. The cephalad prosthesis provides for posterior-anterior adjustment. Both prostheses permit lateral adjustment and adjustment to accommodate interpedicle distance. Further, the prostheses may be customized to provide a pre-defined lordotic angle and a pre-defined pedicle entry angle.

1 . A multi-level spinal stabilization system, comprising: at least two X-shaped members, each X-shaped member having a central member with a superior pair of arms extending from opposed lateral sides thereof and an inferior pair of arms extending from the opposed lateral sides thereof, the superior pair of arms of a first X-shaped member being coupled to an inferior pair of arms of a second X-shaped member.  
   
   
       2 . The multi-level spinal stabilization system of  claim 1 , wherein the at least two X-shaped members are of a unitary construction.  
   
   
       3 . The multi-level spinal stabilization system of  claim 2 , wherein the at least two X-shaped members are formed from an elastomeric material having multiple durometers.  
   
   
       4 . The multi-level spinal stabilization system of  claim 2 , wherein at least a portion of the at least two X-shaped members are formed from a polymeric material.  
   
   
       5 . The multi-level spinal stabilization system of  claim 1 , further comprising first and second connectors adapted to couple the superior pair of arms of the first X-shaped member to the inferior pair of arms of the second X-shaped member.  
   
   
       6 . The multi-level spinal stabilization system of  claim 5 , wherein the first and second connectors each comprise first and second plates pivotally coupled to one another, each plate being adapted to engage a terminal end of one arm of the superior and inferior pair of arms.  
   
   
       7 . A multi-level spinal stabilization system, comprising: at least two X-shaped portions having a unitary configuration, each X-shaped portion having a central spacer adapted to be positioned between posterior elements of adjacent vertebrae, and first and second pairs of arms adapted to couple to adjacent vertebrae.  
   
   
       8 . The device of  claim 7 , wherein the X-shaped portions are formed form an elastomeric material have multiple durometers.  
   
   
       9 . The device of  claim 8 , wherein the at least two X-shaped portions, when coupled to adjacent vertebrae, are adapted to provide resistance to movement of the adjacent vertebrae.  
   
   
       10 . A method for stabilizing multiple adjacent vertebrae; positioning a central spacer of a first X-shaped member between posterior elements of a first vertebra and an adjacent second vertebra; 
 coupling opposed superior arms of the first X-shaped member to the first vertebra; coupling opposed inferior arms of the first X-shaped member to the second vertebra; positioning a central spacer of a second X-shaped member between posterior elements of the second vertebra and an adjacent third vertebra, the second X-shaped member having opposed superior arms that are coupled to the opposed inferior arms of the first X-shaped member; and coupling opposed inferior arms of the second X-shaped member to the third vertebra.    
   
   
       11 . The method of  claim 10 , wherein the opposed superior arms of the second X-shaped member are coupled to the opposed inferior arms of the first X-shaped member by a connector.  
   
   
       12 . The method of  claim 10 , wherein the first and second X-shaped members are of a unitary construction.  
   
   
       13 . The method of  claim 10 , wherein the first and second X-shaped members are formed from an elastomeric material having multiple durometers.  
   
   
       14 . A method for stabilizing multiple adjacent vertebrae, comprising: coupling an implant to a posterior portion of at least three adjacent vertebrae, the implant having a unitary configuration and being formed from an elastomeric material with multiple durometers, and the implant being adapted to provide resistance to movement of the at least three adjacent vertebrae.  
   
   
       15 . The method of  claim 14 , wherein the implant includes at least two central spacers, each central spacer being disposed between posterior elements of two adjacent vertebrae and adapted to limit extension of the adjacent vertebrae.  
   
   
       16 . The method of  claim 14 , wherein each central spacer includes a plurality of arms extending therefrom, and wherein the central spacers are connected to one another by the arms.  
   
   
       17 . The method of  claim 14 , wherein the implant comprises a plurality of X-shaped members coupled to one another.