Patent ID: 8790407

Claim:
An intervertebral spacing implant comprising: a seat having a proximal end and a distal end; a plurality of branches coupled to the distal end of the seat and extending in a distal direction away from the seat, the seat and the branches forming a cage defining an internal volume, each branch having an inward side and an outward side; a spacer configured to fit within the cage and move in the distal direction upon the urging of a spacer-advancing instrument, the spacer and cage configured such that one or more branches will move from an unextended position to an extended position when the spacer is urged in the distal direction; one or more shoulders formed on the inward side of one or more branches, the one or more shoulders configured to reversibly secure the spacer near the distal end of the plurality of branches; an orifice extending from the internal volume of the cage and through the seat to the proximal end of the seat, the orifice configured to allow the spacer-advancing instrument to pass through; and wherein (a) the internal volume between the distal end of the seat and the spacer is unoccupied by a link member when the spacer is secured by the one or more shoulders and the spacer-advancing instrument is removed, and (b) the orifice and the cage are configured to allow insertion of graft material into the internal volume; wherein the spacer has a perimeter, the orifice has a perimeter, and the perimeter of the spacer is greater than the perimeter of the orifice.