Expandable interspinous process spacer with lateral support and method for implantation

Abstract

An interspinous process spacer and method of implanting same is provided for maintaining separation between adjacent spinous processes of adjacent vertebrae. The spacer has two lateral portions and a medial portion therebetween, the medial portion adapted to reside between the adjacent superior and inferior spinous processes in the deployed configuration and the lateral portions each comprise a superior lateral portion and an inferior lateral portion adapted to reside on the lateral side of the respective superior and inferior spinous process in the deployed configuration to maintain positioning of the interspinous process spacer between the two adjacent vertebrae. The lateral portions each comprise an expandable lateral member.

1 . An interspinous process spacer for maintaining separation between adjacent superior and inferior spinous processes of two adjacent vertebrae of a spine, the interspinous process spacer comprising:
 a first spinous process engaging element having one or more teeth configured to grip first and second lateral sides of the superior spinous process;   a second spinous process engaging element having one or more teeth configured to grip first and second lateral sides of the inferior spinous process;   a first central member connected between the first and second spinous process engaging elements on a first lateral side of the spinous processes;   a second central member connected between the first and second spinous process engaging elements on a second lateral side of the spinous processes; and   wherein the first and second central members have a length extending between the first and second spinous process engaging elements, the length sized and configured to space apart the first and second spinous process engaging elements a sufficient distance such that the first and second spinous process engaging elements may engage superior and inferior spinous processes, respectively.   
     
     
         2 . The interspinous process spacer of  claim 1 , wherein each of the first and second spinous process engaging elements has a first leg and a second leg connected by a dorsal segment, the first and second legs configured to engage first and second lateral sides of the spinous process, respectively, with the dorsal segment extending over a dorsal surface of the spinous process, wherein each leg has one or more teeth. 
     
     
         3 . The interspinous process spacer of  claim 2 , wherein the interspinous process spacer is configured such that when positioned over the superior and inferior spinous processes of adjacent vertebrae, the spacer does not extend between the superior and inferior spinous processes in a direction transverse to a longitudinal axis of the spine. 
     
     
         4 . The interspinous process spacer of  claim 1 , wherein the first and second central members have one or more slots configured to facilitate flexion and extension. 
     
     
         5 . The interspinous process spacer of  claim 4 , wherein at least one of the one or more slots includes an enlarged terminal end configured to reduce flexion stress. 
     
     
         6 . The interspinous process spacer of  claim 4 , wherein at least one of the one or more slots extends in a direction between the first and second spinous process engaging elements. 
     
     
         7 . The interspinous process spacer of  claim 1 , wherein the first and second spinous process engaging elements are made of a porous material. 
     
     
         8 . The interspinous process spacer of  claim 7 , wherein the porous material is metal. 
     
     
         9 . The interspinous process spacer of  claim 1 , wherein the first and second spinous process engaging elements are coated with a bone-ingrowth facilitating material. 
     
     
         10 . The interspinous process spacer of  claim 1 , wherein the first and second spinous process engaging elements and the first and second central members are formed as a single member. 
     
     
         11 . An interspinous process spacer for maintaining separation between adjacent superior and inferior spinous processes of two adjacent vertebrae of a spine, the interspinous process spacer comprising:
 first and second clips, each clip having first and second legs with one or more teeth configured to engage first and second lateral sides of a spinous process; and   first and second central members, wherein the first central member extends between and connects the first legs of the first and second clips, and the second central member extends between and connects the second legs of the first and second clips, the first and second central members having a length configured such that the first and second clips are spaced apart a distance corresponding to a distance between the adjacent superior and inferior spinous processes, wherein the interspinous process spacer does not extend between the superior and inferior spinous processes in a direction transverse to a longitudinal axis of the spine.   
     
     
         12 . A method for maintaining separation between adjacent superior and inferior spinous processes of first and second adjacent vertebrae of a spine, the method comprising:
 providing an interspinous process spacer including first and second spinous process engaging elements each having first and second legs, and first and second central members connected between the first and second spinous process engaging elements;   placing the interspinous process spacer over the adjacent spinous processes such that the first and second legs of the first and second spinous process engaging elements are disposed on first and second lateral sides of the superior and inferior spinous processes, respectively, with the first and second central members extending between and on opposite lateral sides of the spinous processes, without extending any portion of the spacer between the superior and inferior spinous processes in a direction transverse to a longitudinal axis of the spine; and   crimping the first and second legs of each of the first and second spinous process engaging elements to the lateral sides of the superior and inferior spinous processes.   
     
     
         13 . The method of  claim 12 , wherein the first and second legs of each spinous process engaging element include one or more teeth, wherein the step of crimping results in the teeth gripping the lateral sides of the spinous processes. 
     
     
         14 . The method of  claim 12 , further comprising inserting one or more fasteners through each spinous process engaging element and into the respective spinous process. 
     
     
         15 . The method of  claim 14 , wherein the one or more fasteners are bone screws.