Method and apparatus for minimally invasive posterolateral spinal fusion

Abstract

Certain embodiments of the invention relate to a surgical procedure resulting in the fusion of transverse processes. The disclosure herein presents novel approaches for accessing transverse processes of the spine, novel methods for the delivery of fusion material for the fusion of said transverse processes, and novel tools to facilitate the procedure. Certain embodiments of the invention include a graft delivery assembly, which has a delivery shaft, delivery sheath, and at least one curved rod. Bony material is position with a graft delivery assembly, in which retraction of the delivery shaft or sheath places the bone fusion material to the fusion site. The graft delivery assembly further includes features to decorticate and prepare the bone surface for fusion.

The claimed invention is: 
     
         1 . A medical device assembly for delivering bone graft, comprising:
 a delivery shaft, said delivery shaft having a tool insertion end and a graft delivery end, said delivery shaft aligned with a central axis, said central axis defining a shaft pathway extending between said tool insertion end and said graft delivery end, said delivery shaft further comprising a handle, said delivery shaft further comprising a retention lock; and   a first element having a first end, a second end, and an exterior surface, said first element aligned with said central axis, said first element being axially slidable through said shaft pathway, said first element further comprising a handle, wherein said delivery shaft retention lock is adapted to retain said first element from sliding.   
     
     
         2 . The assembly of  claim 1 , said delivery shaft further comprising a slot, said slot in communication with said delivery shaft pathway, and wherein said first element handle is a jut protruding from said first element exterior surface, said jut correspondingly passing through said slot and extending past the delivery shaft exterior surface. 
     
     
         3 . The assembly of  claim 2 , wherein said slot further comprises a slot end. 
     
     
         4 . The assembly of  claim 1  further comprising a second element;
 said first element further comprising a pathway extending between said first end and said second end, and defining a hollow form with an interior surface; 
 said second element having a first end, a second end, and an exterior surface, said second element being axially slidable through said first element pathway; and 
 said delivery shaft further comprising a second retention lock adapted to retain said second element from sliding. 
 
     
     
         5 . The assembly of  claim 4 , said second element comprising a mating feature, said mating feature engageable with said second retention lock. 
     
     
         6 . The assembly of  claim 4 , said second element further comprising an abrading surface. 
     
     
         7 . The assembly of  claim 4 , said second element second end further comprising a beveled end configured to create a pathway through tissue. 
     
     
         8 . The assembly in  claim 1 , said retention lock further comprising a retention latch defined by a collar portion rotatable about said shaft central axis, and a latch portion being able to restrict the slideable movement of said first element. 
     
     
         9 . The assembly of  claim 1 , said first element further comprising an abrading surface. 
     
     
         10 . The assembly of  claim 1 , said first element second end further comprising a beveled end configured to create a pathway through tissue. 
     
     
         11 . A medical device assembly for delivering bone graft, comprising:
 a delivery shaft, said delivery shaft having a tool insertion end and a graft delivery end, said delivery shaft aligned with a central axis, said central axis defining a shaft pathway extending between said tool insertion end and said graft delivery end, said delivery shaft further comprising a handle;   a first element having a first end, a second end, and an exterior surface, said first element aligned with said central axis, said first element being axially slidable through said shaft pathway, said first element further comprising a pathway extending between said first end and said second end, and defining a hollow form with an interior surface; said first element further comprising a handle; and   a second element having a first end, a second end, and an exterior surface, said second element being axially slidable through said first element pathway.   
     
     
         12 . The assembly of  claim 11 , wherein said delivery shaft further comprises a retention lock, wherein said delivery shaft retention lock prevents said first element from sliding. 
     
     
         13 . The assembly in  claim 12 , wherein said retention lock comprises a retention latch defined by a collar portion rotatable about said delivery shaft central axis, and a latch portion restricting slideable movement of said first element when said retention latch is positioned in a locking position. 
     
     
         14 . The assembly in  claim 12 , wherein said delivery shaft further comprises a second retention lock wherein said delivery shaft second retention lock prevents said second element from sliding. 
     
     
         15 . The assembly of  claim 11 , said delivery shaft further comprising a slot, said slot in communication with said delivery shaft pathway, and wherein said first element handle is a jut protruding from said first element exterior surface, said jut correspondingly passing through said slot and extending past the delivery shaft exterior surface. 
     
     
         16 . A method of placing bony material between adjacent transverse processes, comprising:
 making an incision in the skin on the posterior side of a patient offset from the medial plane and in proximity to a transverse process;   creating a pathway to a first transverse process through said incision with an assembly, the assembly comprising:
 a delivery shaft, said delivery shaft having a tool insertion end and a graft delivery end, said delivery shaft aligned with a central axis, said central axis defining a shaft pathway extending between said tool insertion end and said graft delivery end, said delivery shaft further comprising a handle, said delivery shaft further comprising a retention lock; and 
 a first element having a first end, a second end, and an exterior surface, said first element aligned with said central axis, said first element being axially slidable through said shaft pathway, said first element further comprising a handle, wherein said delivery shaft retention lock is adapted to retain said first element from sliding; 
   extending said pathway to at least a second transverse process adjacent to said first transverse process with said assembly; and   dispensing bony material through said pathway depositing bony material between said first transverse process and said second transverse process.   
     
     
         17 . The method in  claim 16 , further comprising:
 decorticating the posterior surface of said first transverse process and said at least second transverse process through said pathway, wherein said assembly further comprises an ablating surface configured for decorticating said transverse processes.   
     
     
         18 . The method in  claim 16 , further comprising:
 pre-loading said assembly with bony material and dispensing said bony material between said first transverse process and said at least second transverse process.   
     
     
         19 . The method of  claim 16 , said delivery shaft further comprising a slot, said slot in communication with said delivery shaft pathway, and wherein said first element handle is a jut protruding from said first element exterior surface, said jut correspondingly passing through said slot and extending past the delivery shaft exterior surface. 
     
     
         20 . The method of  claim 16  wherein the assembly further comprises a second element having a first end, a second end, and an exterior surface, said second element being axially slidable through said first element pathway, said first element further comprising a pathway extending between said first end and said second end, and defining a hollow form with an interior surface, and said delivery shaft further comprising a second retention lock adapted to retain said second element from sliding.