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 spinal stabilization device, comprising: a first pair of arms and a second pair of arms, each pair of arms having a superior portion adapted to mate to a superior vertebra, an inferior portion adapted to mate to an inferior vertebra, and a central portion extending between the superior and inferior portions; a central spacer adapted to be positioned between posterior elements of adjacent vertebrae, and having a cross-connector extending therethrough and adapted to engage the central portion of the first and second pair of arms.  
   
   
       2 . The spinal stabilization device of  claim 1 , wherein the cross-connector is slidably adjustable relative to the first and second pair of arms.  
   
   
       3 . The spinal stabilization device of  claim 1 , wherein the cross-connector includes hook-shaped members formed on opposed ends thereof and adapted to engage the central portion of the first and second pair of arms.  
   
   
       4 . The spinal stabilization device of  claim 1 , wherein the central spacer is formed from a polymeric material and is adapted to limit extension of adjacent vertebrae.  
   
   
       5 . The spinal stabilization device of  claim 1 , wherein the first and second pair of arms each have a unitary configuration and are formed from an elastomeric material.  
   
   
       6 . A spinal stabilization device, comprising: a central spacer having first and second opposed lateral sides, the central spacer being adapted to be positioned between posterior elements of adjacent superior and inferior vertebrae and adapted to limit extension of the adjacent superior and inferior vertebrae; and a first pair of arms extending from the first lateral side of the central spacer, the first pair of arms being adapted to couple to adjacent superior and inferior vertebrae, and a second pair of arms extending from the second lateral side of the central spacer, the second pair of arms being adapted to couple to adjacent superior and inferior vertebrae; wherein the central spacer is slidably adjustable relative to the first and second pair of arms.  
   
   
       7 . The spinal stabilization device of  claim 6 , wherein at least a portion of at least one of the first and second pair of arms is pliable for providing resistance to movement of adjacent superior and inferior vertebrae coupled thereto.  
   
   
       8 . The spinal stabilization device of  claim 6 , wherein the first and second pair of arms each have a unitary construction and are formed from an elastomeric material.  
   
   
       9 . The spinal stabilization device of  claim 8 , wherein the central spacer includes a cross-connector extending therethrough and adapted to mate to the first and second pair of arms to allow slidable adjustment of the central spacer relative to the first and second pair of arms.  
   
   
       10 . A method for stabilizing adjacent vertebrae, comprising: coupling a first pair of arms extending from a central spacer to a first lateral side of adjacent superior and inferior vertebrae; coupling a second pair of arms extending from the central spacer to a second lateral side of adjacent superior and inferior vertebrae; sliding the central spacer relative to the first and second arms to position the central spacer as desired; and locking the central spacer in a fixed position relative to the first and second pair of arms.  
   
   
       11 . The method of  claim 10 , wherein the central spacer includes a cross-connector extending therethrough and having opposed ends adapted to engage the first and second pair of arms.  
   
   
       12 . The method of  claim 10 , wherein the central spacer is compressible and is positioned between posterior elements of the adjacent superior and inferior vertebrae to limit extension of the vertebrae.  
   
   
       13 . The method of  claim 10 , wherein the first and second pair of arms each having a unitary configuration and are formed from an elastomeric material.