My sister had a spinal fusion back a few weeks ago. She said they used graft extenders because it was a long fusion and she didn’t have enough bone of her own. Could I have donated bone for her?

When bone grafts are used, the patient donates slivers of bone taken from his or her own ilium (pelvic bone). Bone from a bone bank can also be used. The bone in the bone bank is donated by others, but this occurs after the donor’s death.

The problems and complications that can arise after bone harvest make it difficult for people to donate bone for their own use (much less taking bone from a family member). As a result, scientists are working hard to come up with synthetic (manmade) materials that can be used to help local bone grow.

In 2002, the FDA approved the use of bone graft substitutes. Bone graft substitutes replace bone harvested from the patient or from a donor. Bone morphogenetic protein referred to as rhBMP-2 is an example of a bone graft substitute. At first, BMP was just used for single level spinal fusions.

But results with rhBMP-2 have been so good, its uses have expanded. Surgeons can now use smaller amounts of BMP to get the same results. They can use it in anterior spinal fusions, posterior spinal fusions, and for two-level lumbar spinal fusions. Surgery time is less, blood loss is reduced, and hospital stay is shorter.

The rhBMP-2 sends out signals to attract stem cells that can form bone cells. Graft extenders and bone graft substitutes can be used together. Bone fillers or graft extenders include demineralized bone matrix, TCP-HA (tricalcium phosphate/hydroxyapatite) granules, local bone, and donated bone chips. These biomaterials serve as a three-dimensional scaffold. Stem cells and bone cells can attach here and multiply. Bone tissue engineering eliminates the need for family donors.