I’m going to have a lumbar fusion for severe arthritic degeneration in my lower spine. I have three ways to go: I can get bone from a bone bank. The surgeon can take some bone from my pelvic bone and transfer it to the fusion site. Or they can bypass the real bone and use a new product that is a bone graft substitute. The hospital business office tells me the new technique is less expensive. Why would it be a cost savings to use a product I have to purchase if I could use my own bone instead?

A recently published review of all studies done on bone graft substitutes might help answer your question. The authors of the review looked at the literature already published looking on bone substitutes for lumbar fusion. They limited their search to articles in English. They included studies that used either an anterior (from the front of the spine) surgical approach or posterior (from the back of the spine) surgical approach.

Data collected from the studies included operating time, blood loss, length of hospital stay, surgical approach, and type of fusion material. Results were measured and compared using these factors as well as X-rays evaluating the fusion site. Patient pain, function, and disability were measured using a popular and well-known tool called the Oswestry Disability Index (ODI).

A total of 17 studies made the cut based on the standards set for good quality research methods, the use of English, and fusion for lumbar degenerative osteoarthritis. Most of the focus was on bone graft substitutes. These materials made from bone are called recombinant human bone morphogenetic proteins (rhBMP). There are two types of recombinant BMPs available: rhBMP-2 and rhBMP-7. Some of the studies investigated the results of other bone graft substitutes such as demineralized bone matrix DBM), platelet gels, and activated or autologous growth factor (AGF).

Each of these bone graft materials are prepared and used in a slightly different way to achieve the desired results. BMP-2 is mixed in water and placed on a collagen sponge then placed in a fusion cage between two vertebral bodies (where the disc used to be located). BMP-7 is mixed in a saline (salt) solution and combined with collagen then painted around the sides of the bones to be fused together. Collagen is the basic building material of all soft tissues and bone.

When everything was studied and analyzed, they found that the rhBMP-2 had the best results. Patients receiving the rhBMP-2 bone graft substitute had more stable unions/fusions when compared with rhBMP-7, demineralized bone matrix (DBM), platelet gels, and growth factors. There was less blood loss and shorter operating times with the rhBMP-2. rhBMP-2 outperformed rhBMP-7 in all areas except change in function as measured by the Oswestry Index.

The conclusion of this systematic review of bone graft substitutes for lumbar fusion was that rhBMP is a useful alternative to donor bone or bone harvested from the patient. It is safe and cost-effective. The cost savings come from fewer complications during and after surgery with less blood loss, shorter operating times, and fewer infections. More studies are really needed before any final conclusions can be made.