A stand-alone expandable interbody spinal fusion device including a superior component, an inferior component, an expansion mechanism arranged to displace the superior component in a first direction relative to the inferior component, and a self-piercing screw mechanism arranged within the superior component or inferior component. When torque is applied to the expansion mechanism, torque is transferred 90 degrees thereby displacing a threaded rod or toothed shaft in a first direction thereby displacing the superior component in a first direction relative to the inferior component. When torque is applied to the self-piercing screw mechanism, torque is transferred 90 degrees thereby displacing a self-piercing screw body in a first direction to engage an anchor layer and the bone material of vertebrae thereby holding the interbody spinal fusion device it in place within a disc space.
