Minimally invasive corpectomy cage and instrument

Abstract

An assembly comprising an expandable corpectomy cage and an insertion instrument, wherein the expandable cage comprises an instrument attachment features, including mating holes on the sides of the outer sleeve, and a ball-shaped pocket on the endplate of the inner sleeve, and the insertion instrument features a tuning-fork shaped holder, which attaches to the mating holes on the implant's outer sleeve using small bosses which mate with the holes under the spring tension of the fork, and a lever with a spherical end that mates with the ball-shaped pocket in the inner sleeve endplate.

I claim: 
     
         1 . A method of inserting an expandable spinal corpectomy cage into a defect space between a pair of vertebral bodies, the cage comprising i) an outer member having a first endplate and opposing attachment features defining a rotation axis, and ii) an inner member having a second endplate, wherein the inner member is received within the outer member and is axially adjustable relative thereto in an axial direction thereof for adjusting the variable axial height of the cage, the method comprising the steps of:
 a) attaching the attachment features of the expandable cage to an insertion instrument,   b) inserting the expandable cage into the defect space in an orientation in which the axis of the cage is substantially orthogonal to an axis of the spine, and   c) manipulating the insertion instrument to rotate the expandable cage about the rotation axis so that the axis of the cage is substantially parallel to the axis of the spine.   
     
     
         2 . The method of  claim 1  wherein each of the outer and inner members are sleeves. 
     
     
         3 . The method of  claim 2  wherein the outer sleeve comprises an inner wall and an outer wall having a pair of recesses thereon adapted for mating with the instrument. 
     
     
         4 . The method of  claim 3  wherein the inner sleeve comprises an outer wall and an end plate having a substantially spherical pocket thereon adapted for mating with the instrument. 
     
     
         5 . The method of  claim 2  wherein the outer sleeve comprises an inner wall and an outer wall having a substantially spherical pocket thereon adapted for mating with a first portion of the instrument. 
     
     
         6 . The method of  claim 5  wherein the inner sleeve comprises an outer wall and an end plate having a pair of recesses thereon adapted for mating with a second portion of the instrument. 
     
     
         7 . The method of  claim 2  wherein the instrument comprises a fork comprising a proximal shaft, an intermediate crossbar, and a distal portion comprising a pair of extensions, each extension having a pair of opposing bosses. 
     
     
         8 . The method of  claim 7  wherein the instrument comprises a lever having a proximal shaft, an intermediate portion and a spherical distal end. 
     
     
         9 . The method of  claim 8  wherein the intermediate portion of the lever pivots upon the fulcrum. 
     
     
         10 . The method of  claim 9  wherein the outer member comprises an inner wall and an outer wall having a pair of recesses thereon adapted for mating with an instrument, wherein the opposing bosses mate with the pair of recesses. 
     
     
         11 . The method of  claim 10  wherein the inner member comprises an outer wall and an end plate having a substantially spherical pocket thereon adapted for mating with the instrument, and wherein the spherical distal end of the lever pivotally mates with the spherical pocket. 
     
     
         12 . The method of  claim 1  wherein the cage has a closed configuration in step a), and further comprising the step of:
 d) expanding the cage to an expanded configuration.