Intervertebral implant

Abstract

An adjustable spinal fusion intervertebral implant is provided that can comprise upper and lower body portions that can each have proximal and distal wedge surfaces disposed at proximal and distal ends thereof. An actuator shaft disposed intermediate the upper and lower body portions can be actuated to cause proximal and distal protrusions to converge towards each other and contact the respective ones of the proximal and distal wedge surfaces. Such contact can thereby transfer the longitudinal movement of the proximal and distal protrusions against the proximal and distal wedge surfaces to cause the separation of the upper and lower body portions, thereby expanding the intervertebral implant. The upper and lower body portions can have side portions that help facilitate linear translational movement of the upper body portion relative to the lower body portion.

1 - 36 . (canceled) 
     
     
         37 . A method of implanting an expandable intervertebral implant comprising:
 positioning the implant between two vertebral bodies via a transforaminal approach, wherein the implant comprises:
 an upper body portion having a first upper body end and a second upper body end opposite the first upper body end, wherein the first upper body end defines a first upper body surface, and the second upper body end defines a second upper body surface, and wherein the upper body portion defines first and second upper guide members; 
 a lower body portion having a first lower body end and a second lower body end opposite the first lower body end, wherein the first lower body end defines a first lower body surface, and the second lower body end defines a second lower body surface, and wherein the lower body portion defines first and second lower guide members; 
 a first wedge member that defines first sloped ramp surfaces, wherein the first wedge member further defines respective upper and lower guide members; 
 a second wedge member opposite the first wedge member in the select direction, wherein the second wedge member defines second ramp surfaces sloped opposite the first ramp surfaces, and wherein the second wedge member defines respective upper and lower guide members; and 
   after the positioning step, causing the first and second wedge members to travel toward each other, wherein the causing step forces 1) the first ramp surfaces against the first upper body surface and the first lower body surface, and 2) the second ramp surfaces against the second upper body surface and the second lower body surface, thereby increasing a distance between the upper and lower body portions and expanding the intervertebral implant,   wherein the causing step further causes 1) the upper guide member of the first wedge and the first upper guide member to translate upon each other, 2) the lower guide member of the first wedge and the first lower guide member to translate upon each other, 3) the upper guide member of the second wedge and the second upper guide member to translate upon each other, and 4) the lower guide member of the second wedge and the second lower guide member to translate upon each other,   wherein during the causing step, the first upper body end and the first lower body end separate at a first rate, and the second upper body end and the second lower body end separate at a second rate different than the first rate.   
     
     
         38 . The method of  claim 37 , wherein the causing step causes the first and second wedge members to travel toward each other at different rates. 
     
     
         39 . The method of  claim 37 , wherein the causing step comprises causing the first and second wedge members to travel along a guide member. 
     
     
         40 . The method of  claim 37 , wherein the first sloped ramped surfaces are sloped equal and opposite the second sloped ramped surfaces. 
     
     
         41 . The method of  claim 37 , wherein the causing step expands the intervertebral implant to a wedged shape. 
     
     
         42 . The method of  claim 37 , wherein the upper body portion defines an upper vertebral-facing surface, the lower body portion defines a lower vertebral-facing surface. 
     
     
         43 . The method of  claim 42 , wherein the upper and lower body portions comprise vertebral engaging projections that extend from the upper and lower vertebral-facing surfaces, respectively. 
     
     
         44 . The method of  claim 42 , wherein when the implant is expanded, the upper vertebral-facing surface at the first upper body end and the lower vertebral-facing surface at the first lower body end define a first height, and the upper vertebral-facing surface at the second upper body end and the lower vertebral-facing surface at the second lower body end define a second height that is different than the first height. 
     
     
         45 . The method of  claim 37 , wherein the causing step translates the first and second wedge members translate toward each other along a one-way ratchet.