Abnormalities or degeneration ("wearing") of the discs between vertebrae may lead to abnormal motions causing back and or leg pain. If this pain continues following attempts at rehabilitation, surgery may be recommended. Surgical treatments for this pain commonly involve eliminating motion between affected vertebrae by initiating new bone growth, ultimately joining the two vertebrae together.
The surgical procedure is generally referred to as a spinal fusion procedure. In general, the procedure is completed to induce new bone growth into the space between the transverse processes (posterolateral fusion) or the vertebral bodies (anterior inter-body fusion). The spinal column may be surgically approached via an incision from the back or through the abdomen. A fusion may be attempted either on the front or back side of the spine.
There are different types of spinal fusion.
Anterior inter-body spinal fusion
is performed via an incision in a patient's abdomen. The vertebral bodies are approached from the front and a femoral ring (cadaver bone), or cylindrical cage, is placed between the two vertebral bodies. The femoral ring or cage instrumentation is filled with bone graft usually obtained from the patient's hip (iliac crest). If fusion is successful, motion between the vertebrae will stop and any pain caused by abnormal motion between those vertebrae will no longer exist.
Posterior spinal fusion
Sometimes referred to as a posterolateral spinal fusion, is performed from an incision made in the back. The procedure entails roughening the surfaces of the transverse processes and inserting bone graft between the transverse processes. The bone is usually obtained from a patient's hip. If fusion is successful, motion between the vertebrae will stop and any pain caused by abnormal motion between those vertebrae will no longer exist.
Because of the limited supply of a patient's own bone and possible donor site pain or morbidity, there is a continuing search for ideal bone graft substitute.