Interbody fusion implant and related methods

Abstract

An implant for performing interbody fusion within a human spine, inserters for such an implant, and associated methodology. The implant is preferably formed in situ from at least two separate but lockable members (a base member and a closure member). The base member may be implanted into an interbody space first, after which the end plates may be finally prepared and the base member packed with fusion promoting substances before engaging and locking the closure member. The closure member provides structural support for the adjacent vertebral bodies (along with the base member) and may be selected after implantation of the base member having a specific length, width, height, taper, etc. . . . to ensure an optimal sizing of the implant for desired restoration of disc height, coronal taper, sagittal taper, etc. . . . .

What is claimed is: 
     
         1 . An interbody fusion implant for use in lateral access spinal surgery, comprising:
 a base member having a side walls and an end wall defining an open trailing end and an interior bounded by the side walls and end walls, at least a portion of the end wall dimensioned to serve as a structural support between cortical bone regions of adjacent vertebral bodies in the lumbar or thoracic spine, and the side walls and end wall dimensioned to serve as a protective barrier between the interior and adjacent neural structure and/or vasculature; and   a closure member dimensioned to be coupled to the base member to enclose the interior after the base member has been positioned in a preliminarily prepared disc space in between said vertebral bodies and end plate preparation has taken place within the interior of the base member, the closure member being dimensioned such that at least a portion of the closure member provides structural support between cortical bone regions of adjacent vertebral bodies.   
     
     
         2 . A system for performing lateral interbody fusion, comprising:
 a base member having a side walls and an end wall defining an open trailing end and an interior bounded by the side walls and end walls, at least a portion of the end wall dimensioned to serve as a structural support between cortical bone regions of adjacent vertebral bodies in the lumbar or thoracic spine, and the side walls and end wall dimensioned to serve as a protective barrier between the interior and adjacent neural structure and/or vasculature;   a closure member dimensioned to be coupled to the base member to enclose the interior after the base member has been positioned in a preliminarily prepared disc space in between said vertebral bodies and final end plate preparation has taken place within the interior of the base member, the closure member being dimensioned such that at least a portion of the closure member provides structural support between cortical bone regions of adjacent vertebral bodies;   a base member inserter for inserting the base member into the preliminarily prepared disc space, the base member inserter including a body region dimensioned to extend into the interior of the base member to provide structural support for the base member during introduction; and   a closure member inserter for inserting the closure member into engagement with the base member after the final endplate preparation has taken place within the interior of the base member and after fusion promoting material has been introduced into the interior of the base member.   
     
     
         3 . The system of  claim 2 , comprising a delivery system for delivering the fusion promoting material into the interior of the base member after the final endplate preparation has occurred and before the closure member has been engaged with the base member. 
     
     
         4 . The system of  claim 2 , wherein the closure member includes a locking mechanism for locking the closure member to the base member. 
     
     
         5 . The interbody fusion implant of  claim 1 , wherein the closure member is coupled to the base member via at least one locking member. 
     
     
         6 . The interbody fusion implant of  claim 5 , wherein the at least one locking member comprises a locking pin dimensioned to extend at least partially within the closure member and at least partially within the base member. 
     
     
         7 . The interbody fusion implant of  claim 6 , wherein the locking pin is rigidly disposed within a proximal end of the base member and releasably disposed within a recess formed within the closure member. 
     
     
         8 . The interbody fusion implant of  claim 7 , wherein the closure member includes a secondary locking mechanism. 
     
     
         9 . The interbody fusion implant of  claim 8 , wherein the secondary locking mechanism includes an actuating element and at least one secondary locking element in communication with the recess. 
     
     
         10 . The interbody fusion implant of  claim 9 , wherein the secondary locking element is a transverse pin member configured to be driven by the actuating element into locking engagement with the locking pin. 
     
     
         11 . The interbody fusion implant of  claim 10 , wherein the actuating element includes a generally tapered distal end which drives the transverse pin member into contact with the locking pin as the actuating element is rotatably advanced towards a distal end of the closure member. 
     
     
         12 . The interbody fusion implant of  claim 11 , wherein the locking pin has serrations formed along at least a portion of an exterior surface which facilitate engagement between the locking pin and the transverse pin member. 
     
     
         13 . The interbody fusion implant of  claim 5 , wherein the at least one locking member extends from the closure member for engagement with the base member. 
     
     
         14 . The interbody fusion implant of  claim 13 , wherein the locking member comprises a hook member dimensioned to engage with a recess formed in the base member. 
     
     
         23 . The interbody fusion implant of  claim 14 , wherein the closure member includes an actuating element dimensioned to be selectively driven into contact with the hook member. 
     
     
         15 . The interbody fusion implant of  claim 15 , wherein the actuating element is rotatably driven into contact with the hook member by an instrument. 
     
     
         16 . The interbody fusion implant of  claim 16 , wherein rotation of the actuating member forces the hook member into engagement within the recess and thereafter prevents the hook member from disengagement with the recess. 
     
     
         17 . The interbody fusion implant of  claim 5 , wherein the closure member includes a distal end having an angled portion, and wherein the base member includes a proximal end having an angled portion for mating engagement with the angled portion of the closure member. 
     
     
         18 . The interbody fusion implant of  18 , wherein the angled portion of the closure member includes a groove and wherein the angled portion of the base member includes a tab dimensioned to be received within the groove of the angled portion of the closure member. 
     
     
         19 . The interbody fusion implant of  claim 18 , wherein the at least one locking member extends from the closure member for engagement with the base member. 
     
     
         20 . The interbody fusion implant of  claim 19 , wherein the locking member comprises a hook member dimensioned to engage with a recess formed in the base member.