A
spinal fusion system includes a cage with a fillable volume and removable locking gate, thereby enabling the fillable volume to be packed with graft, biologic or other materials prior to the gate being closed and locked. In the preferred embodiment, the locking gate is positioned anteriorally, though lateral, posterior, and combinations thereof are also possible. The cage is preferably radiolucent, being composed of a carbon
fiber, but with one or more radiopaque markers to provide a certain degree of
visualization. Some or all of the walls of the cage may include superior and / or inferior surface features to enhance positioning and / or minimize back-out, and the
posterior wall may be indented to prevent neurocompression. The sidewalls of the cage may further include a recessed face with nipple indents and locking fasteners. According to a
system aspect of the invention, multiple cages are provided, each being shaped differently for use at different spinal levels. For example, the cage may be larger and more trapezoidally-pronounced for the L5-S1 levels, or smaller and less trapezoidally pronounced for the T and L2 levels. The
system may further including an
implant introducer instrument geometrically matched to the cage, and the matched
implant introducer instruments and cages may be color-coded to expedite the procedure.