Expandable intervertebral cage assemblies

Abstract

An expandable assembly for insertion into an intervertebral space is presented. The assembly, in particular aspects, includes an elongate body comprising an upper portion and a lower portion, wherein the elongate body defines an internal longitudinal channel extending from a proximal opening to a distal cavity. The assembly may include an expander that is sized and shaped for insertion into the distal cavity, thereby selectively expanding the upper portion away from the lower portion. The elongate body may also include one or more bone graft windows a cap that is sized and shaped for insertion into the proximal opening.

1 . An expandable cage for insertion into an intervertebral space, comprising:
 a cage body having a leading end, a trailing end, an upper portion and a lower portion, the upper portion having a an upper bone contact surface and an upper portion lower surface, the lower portion having a lower bone contact surface and a lower portion upper surface, wherein the upper portion and lower portion are connected and wherein the upper portion lower surface and lower portion upper surface define an internal space;   an elongate expander positioned at least partially therein the internal space, wherein a proximal portion of the elongate expander defines an aperture in communication with the internal space wherein translation of the elongate expander proximally toward the trailing end of the cage body moves the cage body into an expanded position by separating at least a portion of the upper portion of the cage body from at least a portion of the lower portion of the cage body; and   an actuating screw positioned within the aperture engaged with the proximal portion of the expander and having a screw head, wherein rotation of the actuating screw in a first direction moves the elongate expander proximally, and rotation of the elongate screw in a second direction moves the elongate expander distally;   wherein, the cage body comprises a shoulder substantially adjacent the trailing end, the shoulder defining an orifice configured for receipt of the actuating screw, whereby rotating the actuating screw in the first direction until the cage body is in the expanded position, sandwiches at least a portion of the shoulder between portions of the screw head and the proximal portion of the elongate expander.   
     
     
         2 . The expandable cage of  claim 1 , wherein an upper portion of the shoulder is integral with the upper portion of the cage body. 
     
     
         3 . The expandable cage of  claim 1 , wherein the upper portion has an upper portion inner surface and the lower portion has a lower portion inner surface, and wherein portions of the distal portion of the expander are complimentarily shaped with at least one of the upper portion inner surface and the lower portion inner surface, whereby pulling the expander proximally cams the distal portion of the expander against the at least one of the upper portion inner surface and the lower portion inner surface to expand the cage body. 
     
     
         4 . An expandable cage for insertion into an intervertebral space, comprising:
 a cage body having a leading end, a trailing end, an upper portion and a lower portion, the upper portion having a an upper bone contact surface and an upper portion lower surface, the lower portion having a lower bone contact surface and a lower portion upper surface, wherein the upper portion and lower portion are connected and wherein the upper portion lower surface and lower portion upper surface define an internal space;   an elongate expander positioned at least partially within the internal space, wherein a proximal portion of the elongate expander defines an aperture in communication with the internal space wherein translation of the elongate expander proximally toward the trailing end of the cage body moves the cage body into an expanded position by separating at least a portion of the upper portion of the cage body from at least a portion of the lower portion of the cage body, wherein a portion of the upper portion of the cage body substantially adjacent the trailing end defines a first trough and a portion of the lower portion of the cage body substantially adjacent the trailing end defines a second trough;   an actuating screw positioned within the aperture; and   a first shim positioned within the first trough and a second shim positioned within the second trough, the first and second shims forming a shoulder, wherein the first and second shims define an orifice substantially coaxial with the aperture.   
     
     
         5 . The expandable cage of  claim 4 , wherein the actuating screw comprises a head having a head diameter, and wherein the orifice has an orifice diameter, and wherein the orifice diameter is smaller than the head diameter. 
     
     
         6 . The expandable cage of  claim 5 , wherein, when the elongate expander is pulled proximately the first and second shims are sandwiched between the elongate expander and the head of the actuating screw. 
     
     
         7 . The expandable cage of  claim 6 , wherein an insertion tool moves the expander from the first position to the second position by pulling the expander proximally. 
     
     
         8 . The expandable cage of  claim 4 , wherein the first shim and the cage body comprises a first material and the first and second shim comprise a second material, wherein the second material is harder than the first material. 
     
     
         9 . The expandable cage of  claim 8 , wherein the first material is PEEK. 
     
     
         10 . The expandable cage of  claim 9 , wherein the second material is Titanium. 
     
     
         11 . A system comprising:
 an expandable cage comprising:   a cage body having a leading end, a trailing end, an upper portion and a lower portion, the upper portion having a an upper bone contact surface and an upper portion lower surface, the lower portion having a lower bone contact surface and a lower portion upper surface, wherein the upper portion and lower portion are connected and wherein the upper portion lower surface and lower portion upper surface define an internal space;   an elongate expander positioned at least partially within the internal space, wherein a proximal portion of the elongate expander defines an aperture in communication with the internal space wherein translation of the elongate expander proximally toward the trailing end of the cage body moves the cage body into an expanded position by separating at least a portion of the upper portion of the cage body from at least a portion of the lower portion of the cage body;   an actuating screw positioned within the aperture engaged with the proximal portion of the expander and having a screw head, wherein rotation of the actuating screw in a first direction moves the elongate expander proximally, and rotation of the elongate screw in a second direction moves the elongate expander distally, and wherein, the cage body comprises a shoulder substantially adjacent the trailing end, the shoulder defining an orifice configured for receipt of the actuating screw, whereby rotating the actuating screw in the first direction until the cage body is in the expanded position, sandwiches at least a portion of the shoulder between portions of the screw head and the proximal portion of the elongate expander; and   an insertion tool for inserting the expandable cage between two adjacent vertebrae, the insertion tool being cannulated and defining an internal chamber.   
     
     
         12 . The system of  claim 11 , wherein the insertion tool comprises an outer sleeve defining the internal chamber and a drive rod positioned within the internal chamber, and wherein a distal portion of the outer sleeve is configured for releasable engagement with a portion of the trailing end of the expandable cage. 
     
     
         13 . The system of  claim 11 , wherein a distal end of the drive rod is configured to engage a portion of the actuating screw to enable rotation thereof.