I'm going to have a spinal fusion for severe degenerative disc disease at L4/5. Since I am mildly osteoporotic, I can't donate bone to myself. The doctor wants to try something called rhMBP-2 instead. What can you tell me about this?

The FDA has approved the use of rhBMP-2 for spinal fusion surgery. These initials stand for recombinant human bone morphogenetic protein. This is a genetically produced biologic protein. It can cause the body to grow its own bone where needed. This new way to do spinal fusions is less invasive and less painful. Patients also have a quicker recovery time.

Studies show that patients who are implanted with rhBMP-2 are able to get good spinal fusion even without the use of metal implants (rods and screws). These patients have shorter surgical time, less blood loss, and less pain after the operation.

Right now this method is being used for patients with degenerative disc disease, arthritis of the spine, instability of the spine, and spondylolisthesis. The protein comes in a powder form. It's combined with saline and put on a tiny sponge. The spone is put inside a special cage inserted between two vertebrae in place of a damaged disc.

Cells that come in contact with the protein start to grow bone cells. After a short time the bone grows through the sponge and around parts of the cage. This is what fuses the vertebrae together.