The best clinical results are generally achieved in single-level fusion, although fusion at two levels may be performed in properly selected patients.

Bone grafts may be taken from the hip or from another bone in the same patient (autograft) or from a bone bank (allograft). Bone graft extenders and bone morphogenetic proteins (hormones that cause bone to grow inside the body) can also be used to reduce or eliminate the need for bone grafts.

Fusion sometimes involves the use of supplemental hardware (instrumentation) such as plates, screws, and cages. This fusing of the bone graft with the bones of the spine will provide a permanent union between those bones. Once that occurs, the hardware is no longer needed, but most patients prefer to leave the hardware in place rather than go through another surgery to remove it. Fusion can sometimes be performed via smaller incisions through MIS techniques. The use of advanced fluoroscopy and endoscopy has improved the accuracy of incisions and hardware placement, minimizing tissue trauma while enabling an MIS approach.