Distractable spinal implant assembly

Abstract

A spinal implant assembly includes a housing for containing a bearing member therein and seating within an intervertebral space and a bearing member disposed within the housing for enabling disc-like movement between vertebrae defining the intervertebral space. A method of inserting the spinal implant assembly into the intervertebral space includes the steps of inserting the spinal implant assembly into the intervertebral space and then distracting the spinal implant assembly from a first condition in which the spinal implant assembly is floatable into the intervertebral space to a second condition in which the assembly is distracted to fixedly engage opposing vertebral services defining the intervertebral space.

1 . A spinal implant assembly comprising
 housing means for containing a bearing member therein and seating within an intervertebral space;   bearing means disposed within said housing for enabling disc like movement between vertebrae defining the intervertebral space; and   distracting means disposed within said housing for distracting said housing means from a first condition in which said housing means is floatable into the intervertebral space to a second condition in which said housing means is distracted to fixedly engage the opposing vertebral surfaces defining the intervertebral space;   wherein said housing means includes at least a first and second housing member for containing said bearing means therein and therebetween, at least one of said housing means including a ramping surface over which said bearing means seats and travels whereby translating of said bearing means from a first position on said ramping surface to a second position on said ramping surface distracts said housing means from said first condition to said second condition;   wherein each of said housing members includes a recessed opening therein juxtaposed to each other defining an internal housing cavity, and seating said bearing means therein, at least one of said recessed openings including said ramping surface;   and including a base member disposed within said internal housing cavity for containing said bearing means therein and biasing means of a Bellville washer disposed between said base member and said ramping surface provided cushioned movement of said base member towards and away from said ramping surface thereby allowing lateral bending of vertebrae about said spinal implant assembly.   
     
     
         2 . The spinal implant assembly as set forth in  claim 1 , wherein said washer is made from a material from a group including titanium, cobalt, chrome and stainless steel and polymers. 
     
     
         3 . The spinal implant assembly as set forth in  claim 2 , wherein said polymer is selected from the group including silicone, hydrogels, and polyurethanes. 
     
     
         4 . A spinal implant assembly comprising
 housing means;   bearing means disposed within said housing means for enabling disc-like movement between vertebrae defining an intervertebral space; and   adjustment means for adjusting a center of rotation of said assembly relative to the intervertebral space after said assembly has been inserted into the intervertebral space.   
     
     
         5 . A spinal implant assembly comprising
 stabilizing means for stabilizing an intervertebral space; and   motion restoring means for restoring anatomical motion to vertebrae defining the intervertebral space.   
     
     
         6 . A method of inserting a spinal implant assembly into an intervertebral space, said method including the steps of:
 inserting the spinal implant assembly into an intervertebral space and then distracting the spinal implant assembly from a first condition in which the spinal implant assembly is floatable into the intervertebral space to a second condition in which the assembly is distracted to fixedly engage opposing vertebral surfaces defining the intervertebral space.   
     
     
         7 . The method as set forth in  claim 6 , further including the steps of retracting the spinal implant assembly after implantation into the intervertebral space and removing the implant therefrom. 
     
     
         8 . The method as set forth in  claim 6 , wherein said distracting step is further defined as distracting the spinal implant assembly into the second condition while expanding the intervertebral space. 
     
     
         9 . A method of inserting a spinal implant assembly into an intervertebral space, said method including the step of:
 adjusting the center of rotation of the spinal implant assembly after the assembly has been inserted into the intervertebral space.   
     
     
         10 . The method as set forth in  claim 9 , wherein said adjusting step is further defined as inter-operatively altering the center of rotation after the spinal implant assembly is inserted into the intervertebral space while not disturbing interfaces between the adjacent vertebrae and the spinal implant assembly. 
     
     
         11 . A method of inserting a spinal implant assembly into an intervertebral space, said method including the steps of:
 inserting the spinal implant assembly into the intervertebral space;   stabilizing the intervertebral space; and   restoring anatomical motion to the vertebrae defining the intervertebral space.   
     
     
         12 . A method of inserting a spinal implant assembly into an intervertebral space by posteriorly inserting two spinal implant assemblies into the intervertebral space, and adjusting the center of rotation of each of the implants in situ. 
     
     
         13 . An insert member for a spinal implant assembly comprising:
 a cylindrical portion including a first end having a substantially flat surface and   a bearing portion operatively connected to second end of said cylindrical portion.   
     
     
         14 . The insert member as set forth in  claim 13 , wherein said bearing portion is substantially hemispherical.