BONE TRANSPLANTATION

Bone transplantation or bone grafting, as it is more commonly known is a surgical procedure where surgeons use an external source of a bone or a bone substitute to replace bone tissue lost due to cancer, trauma or infection.

A human bone has the ability to heal itself by forming new bone. Sometimes, this ability is hindered due to extensive bone loss after severe trauma, surgical removal of bone tumors or after removal of bone infections. This leaves a large defect, which typically would not heal without a bone graft.

Bone grafts can usually be obtained from three sources:
A) autologous – bone harvested from a different area from the patient’s own body.
B) allograft – bone harvested either from a deceased donor or from a living donor who has donated a small part of his bony skeleton, as happens after a hip replacement, where the donor agrees to donate a part of the hip bone being removed during the procedure that would normally be discarded.
C) synthetic – using an artificial substance with similar mechanical properties as a bone.
Most bone grafts are finally reabsorbed and replaced as the natural bone heals after a few weeks.

Autologous bone grafts use bone from a non-essential area such as the iliac crest or the hip bone, the leg (fibula), ribs, mandible (jaw) and the skull. Advantages of using one’s own bone is that it reduces the chance of getting an infection from another donor and of graft rejection. Disadvantages include another potential source of pain, infection and other complications at the second site from where the bone graft is obtained.

Allograft bone is obtained either from a deceased or a living donor. These are typically obtained from bone banks after they have gone through stringent testing requirements in order to enhance their safety.

Synthetic bone substitutes include materials like hydroxylapatite, which occurs naturally and can sometimes be used in combination with other minerals or polymers. Ceramics have been used extensively to create artificial bone substitutes as well. Corals from the ocean have been found to be excellent bone substitutes as well.

Common uses of bone grafts include their use as support structures for dental implants and for reconstruction procedures after bone loss from infections, tumors and trauma involving the jaw bone. The fibula is also used as a bone graft for long bone reconstructions involving the lower or upper limbs.

Recent advances in biotechnology has an Israeli company use a lab-grown semi-liquid bone graft, grown from a patient’s own fat cells, be used as a viable replacement for lost areas of the jaw bone in 11 patients, with great long term results. This would undoubtedly lead to more research and innovation to come up with safer, more abundant natural sources of bone substitutes at a lower cost to benefit a wider section of mankind.