More and more surgeons are looking for safe substitutes for bone grafts. Major spine surgery requires a large amount of graft material. Sometimes this is more than the patient can donate and more than is available in the bone bank.
In such cases, a substitute product called a bone extender may be used. The most common material is calcium phosphate. It has just the right surface area (density) and pore size to allow for bone ingrowth.
The natural bone in the area reacts to the presence of this material. Bone cells may grow faster and bond to the surface of the bone substitute. The calcium phosphate product gives the bone a place to anchor and grow.
Scientists are studying ways to help bone grow, attach, and spread where needed. Sometimes the bone growth is faster with substitutes but not always. It’s not clear what happens at the molecular level to promote bone growth.
Some studies are being done to find out. Red blood cells have been injected into the bone subsitute. It may be possible for cell attachment to occur faster when there are serum (blood) proteins present.
Firm conclusions about the use of these products aren’t available yet. In the future, there may be enough studies with different materials to allow comparisons between various products currently available.