Spinal fusion, one of the most common types of spinal stenosis surgeries, requires a bone graft to facilitate the growth of new bone between two or more vertebrae. The graft is placed between adjacent vertebrae once an intervertebral disc has been removed. Over time, the graft helps the vertebrae to fuse into one solid segment of bone. The goal of this procedure is to stabilize the spine, relieve neural compression caused be the spinal stenosis, and eliminate pain caused by movement at the affected level of the spine.
The bone graft used for spinal fusion can take several forms, including:
- An autograft – This type of graft is taken from the patient’s own body (usually the pelvic bone) during a harvesting procedure prior to fusion. This is the most common type of bone graft, as it reduces the risk of infection and rejection. Some patients with poor bone quality or those who do not want to undergo a harvesting procedure opt for other types of bone grafts.
- An allograft – This type of bone graft is obtained from a bone bank. The bone is harvested from cadavers. In some cases, allograft bone is added to autograft bone. An allograft for spinal fusion is usually in morselized form and is contained within a small cage that is secured between the adjacent vertebrae.
- Bone graft substitutes – Substitutes may take the form of bone morphogenic protein (BMP) or demineralized bone matrix (DBM). BMP utilizes bone-forming proteins in the body, whereas DBM is a manufactured product that contains cortical bone from which the calcium and phosphorous have been removed.
The use of a bone graft in spinal fusion does increase some risks associated with the procedure, primarily infection, graft rejection, and failed back surgery syndrome. If you do decide to undergo spinal fusion, be sure to talk to your doctor thoroughly about the risks and the type of graft that is right for you. Patients who do not want a bone graft implanted in their spines may want to consider a minimally invasive procedure that does not involve fusion.