Spinal fusion is aided by the placement of bone chips placed alongside and between the vertebral bodies. These bone graft materials help jump start the healing process and foster a successful fusion.
There are two basic bone grafts: autografts (harvested from the patient) or allografts (obtained from a donor bank). Donor bank bone comes from cadavers (bone preserved after death for use in studies or surgery). Live donors (other than the patient himself) are not used because of what’s referred to as donor site morbidity and the risk of tissue rejection. Patients donating bone would be at risk for post-collection infection, pain, and disability at the donor site.
Autografts are really still considered the gold standard (the best choice). Using your own bone means there won’t be any issues with tissue rejection. And since it’s live bone when it’s harvested, it helps stimulate new bone growth at the surgical site much faster and more efficiently than allografts.
The major disadvantage of autografts is persistent and sometimes disabling pain at the donor site. As your own donor, you may suffer more from the donor location than from the main area of surgery. A minor inconvenience is the extra time during surgery to collect the bone from some other site. Autografts for spinal fusion usually come from bone removed from the spine (e.g., laminae or spinous process) or from the crest of the pelvic bone.
Allografts on the other hand create no donor site problems, but fusion takes longer and there is a risk of transferring an infection from the donor tissue to the recipient. That’s why donors are screened very carefully before being accepted and the donor tissue is sterilized with gamma irradiation techniques. Advantages of allografts include shorter surgical time, availability of preformed shapes and sizes of donor tissue, and as mentioned, there’s no pain from bone collection.