An adjustable spinal fusion intervertebral implant including upper and lower body portions each having proximal and distal surfaces at proximal and distal ends thereof. The implant can include a proximal wedge member disposed at the proximal ends of the respective ones of the upper and lower body portions, and a distal wedge member disposed at the distal ends of the respective ones of the upper and lower body portions. First and second linkages can connect the upper and lower body portions. Rotation of an actuator shaft can cause the distal and proximal wedge members to be drawn together such that longitudinal movement of the distal wedge member against the distal surfaces and the longitudinal movement of the proximal wedge member against the proximal surfaces causes separation of the upper and lower body portions.