UIC SURGEONS REGENERATE BONE TO REPAIR FACIAL DEFORMITIES
UIC oral and maxillofacial surgeons are using an unusual technique to replace lost bone tissue in the jaw.
Instead of grafting bone from the femur, pelvis or skull - the usual methods - Leslie Heffez, professor and head of oral and maxillofacial surgery in the College of Dentistry, and colleagues have been using a technique called distraction osteogenesis to regenerate bone from existing tissue.
The technique has proven highly successful. In one case, a patient's entire half jaw was reconstructed after cancer surgery left the woman with a gaping hole. The bone began to grow back in about three months with little or no discomfort for the patient.
In distraction osteogenesis, a vice-like frame called a distractor sits around the patient's head and is attached to the patient's jaw using pins. The surgeon creates a tiny fracture in the bone and then, by turning screws in the distractor, pulls the bone apart to create a small gap. Over time, the bone grows to fill in the missing tissue. The procedure is repeated multiple times until the bone has completely regenerated.
"Essentially, we fool the body into activating its natural healing mechanism," said Heffez.
Distraction osteogenesis is less time-consuming and, consequently, safer than bone grafting, which involves an operation lasting anywhere from 10 to 15 hours depending on how much bone needs to be replaced. Moreover, distraction osteogenesis can begin immediately after cancer or other major oral or maxillofacial surgery, while grafting is often delayed until the patient has healed. The risk of infection is smaller, too, since there is only one surgical site, not two (the area from which bone is taken and the site of the graft). Although distraction osteogenesis requires two surgeries - the first to implant the device, the second to attach new bone to old once regrowth is completed - both are usually minor operations that can be done in a doctor's office or in the hospital on an outpatient basis.
The procedure is especially advantageous for patients who have received radiation therapy. To undergo a bone graft, these patients first typically require a series of expensive oxygen treatments to improve the local blood supply. No such treatments are necessary with distraction osteogenesis.
Heffez first offered the procedure to a patient who he felt would not be able to tolerate lengthy surgery under general anesthesia and a prolonged recovery time, but now offers it as a first choice to patients to replace large missing bone structures.
The technique was originally used to lengthen limbs. Over the last few years, however, distraction osteogenesis has been applied to facial bones: to correct congenital deformities in which a part of the facial structure is too small (hemifacial microsomia) or not sufficiently formed (cleft lip and palate). It has also been used to enlarge the jawbone in preparation for teeth implants.
For the first time, UIC surgeons are using distraction osteogenesis to repair defects caused by serious accidents and cancer surgery - the most difficult types of facial reconstruction.
"For cancer patients who have undergone so much trauma already - lengthy surgery, chemotherapy and possibly radiation treatment - this procedure offers definite advantages," said Heffez. "Patients can begin reconstruction on the day the tumor is resected - imagine the hope that that instills!"
To date, nine patients with severe facial deformities have undergone distraction osteogenesis at UIC - one with a bony cleft deformity and eight who had had tumors of the jaw removed. Three of those eight patients began bone reconstruction on the day their cancer surgery was performed. The bone has regenerated in all cases, and in most, reconstruction is nearly completed.
Heffez and colleagues are now working on a distractor design that would place the device inside the mouth, making it cosmetically more acceptable to patients.
- UIC -
Copyright © 2000 University of Illinois at Chicago