Bone Graft Options

The main bone graft options used in spine fusions are:

• Bone from the patient (autograft)
  This option involves removing healthy bone from the patient, typically from the patient’s hip (pelvis), in a procedure that is done at the same time as the spinal fusion surgery. This type of bone graft is considered optimal, as it has all of the qualities needed to help achieve a fusion and has no risk of disease transmission (vs. using cadaver bone). The drawback is that there is a risk of postoperative pain in the hip area where the bone is removed, and in some cases (with recent studies, of 100-200 patients each, indicating 25%-30% of patients), this discomfort may become chronic (persisting 24-48 months after the surgery). ^{1 2} Additionally, there can be insufficient quantity or quality of bone there for available harvesting.


• Cadaver bone (allograft)
  This form of bone graft is harvested from a cadaver by a tissue bank. Using cadaver bone eliminates the potential surgical risks associated with taking bone from the patient. While there are many quality control steps in the process of harvesting and processing cadaver bone, the possible risk of disease transmission cannot be totally eliminated. While allograft bone does not have any living cells that are required to stimulate new bone growth, and thus has a lower chance of fusion as compared to using the patient’s bone, it has proven comparable in certain studies to autograft in terms of producing successful fusions. ^{3 4 5}


• DBM (demineralized bone matrix)
  DBM is allograft (cadaver bone graft) that has been processed (demineralized) to extract the natural proteins that promote bone formation. After processing, DBM is available for use in spine fusion in a number of forms, such as powder, putty or chips.


• Ceramic-based synthetics (also known as synthetic bone graft)
  There are several synthetic substances such as Calcium Phosphates (CaP) that have similar chemistries and structures to that of natural bone. When mixed with bone marrow aspirate (BMA), they have biological activity that helps regenerate bone growth within the surgical site. There are various clinical studies supporting the clinical efficacy of this type of combination in growing bone in a spinal fusion. Unlike allograft, these products do not present the risk of disease transmission, and they eliminate the need to harvest autograft, and thus eliminate surgical morbidity.


• Bone Marrow Aspirate (BMA)
  Bone marrow is the soft tissue inside bones that contains stem cells that help form bone. It is found in the hollow part of most bones. Bone marrow aspiration is the removal of a small amount of this tissue in liquid form via a minimally invasive approach. Bone marrow aspiration can be done at several places on the body, generally from the back of the pelvic bone or from the vertebral body during surgery, to remove enough bone marrow cells to add to a synthetic bone graft. The principal advantage of using this approach is that it provides cells and biological growth factors that assist in the healing and regeneration of bone without the morbidity of autograft.


• BMP (Bone Morphogenetic Proteins)
  BMP’s are proteins that can be produced, concentrated and used to promote bone growth to achieve a spine fusion. Although BMP has been shown to work well in numerous applications, there are some unique complications that have been reported with off-label use, i.e. cervical (neck) spine procedures. BMP is approved for use in ALIF (anterior lumbar interbody fusion) procedures of the spine. ^{6 7}