Medical Health Encyclopedia

Graft Materials. Bone grafts are taken from the patient's hip, ribs, spine, or other bones (called autografts). This is the best quality bone. However, because autografts are taken directly from the scoliosis patient, the operation is longer and the patient experiences more pain afterward. Researchers are also investigating allografts, which are bone grafts taken from another person or a cadaver. This would reduce the pain and duration of the operation. Allografts, however, pose an increased risk for infection from the donor. Longer-term studies are needed to determine the seriousness of this risk.

Investigators have been testing grafts made from ceramic material called tricalcium phosphate (Biosorb). In one comparative French study, these synthetic grafts were completely fused with the original bone in two years, while the natural bone graft was still evident on x-rays. In the study, the use of synthetic graft was associated with better spinal correction and a lower risk for viral infections.

Healing. The healed fusions harden in a straightened position to prevent further curvature, leaving the rest of the spine flexible. It takes about three months for the vertebrae to fuse substantially, although one to two years are required before fusion is complete. Fusion stops growth in the spine, but most growth occurs in the long bones of the body (such as in the legs), anyway. Patients, then, will most likely gain height from both growth in the legs and from the straighter spine. Patients make walk at slightly slower pace after fusion, but balance may improve, and sports activities are not restricted after the procedure.

Instrumentation

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Harrington Procedure. Until ten years ago, the standard instruments used in fusion procedures were those of the Harrington procedure, first developed in the 1960s:

• To support the fusion of the vertebrae, the surgeon uses a steel rod, extending from the bottom to the top of the curve. (More than one rod may be used depending on the type of curve and whether kyphosis is present.)
• The rod is attached by hooks that are suspended from pegs inserted into the bone.
• Similar to changing a tire, the steel rod is jacked up and then locked into place to support the spine securely. The surgeon is then ready to fuse the vertebrae together.
• After this operation, patients are required to wear a full body cast and lie in bed for three to six months until fusion is complete enough to stabilize the spine.
• After one to two years, the steel rod is not really necessary, but it is almost always left in place unless infection or other complications occur.