Ear, nose and throat surgeons at the Mayo Clinic, Rochester, Minn., have developed a process for mandible reconstruction after removal of oral cancer.
The method, which the investigators tested in rabbits, uses distraction osteogenesis after tumor removal surgery to restore the missing portion of a patient’s jaw. The surgeon makes a cut at one of the remaining ends of the jawbone. As the break heals, soft tissue—the first phase of growth—appears. The surgeon then stretches the pliable soft tissue under the tension of a device to fill in the gap in the patient’s jaw. Within 24 hours of completing the stretching process, physicians begin radiation therapy to the mandible to decrease the likelihood of cancer recurrence. As the soft tissue heals, it hardens into bone.
The investigators found that radiation therapy, which they had suspected might interrupt the bone consolidation, had no ill effects on the bone’s healing.
"Patients with large oral tumors should have radiation therapy after surgery to decrease the chances of cancer recurrence," said Daniel Price, MD, ear nose and throat surgery resident at the Mayo Clinic and the study’s lead investigator. "Radiation needs to be completed 13 to 14 weeks after the patient’s cancer diagnosis to achieve maximum effect. As these patients require mandible reconstruction after tumor removal, we wanted to find a way to get both the radiation and the reconstruction done quickly and concurrently."
The standard procedure for jaw reconstruction after removal of oral cancer is to transfer bone from the patient’s fibula in the leg, along with surrounding muscle, skin and the supplying vessels. Although the esthetic and functional result for the mandible can be good, this procedure has several drawbacks.
"If we could avoid the whole process of going to another part of the body in order to reconstruct a patient’s jaw, it would be best," said Eric Moore, MD, ear, nose and throat surgeon and the study’s senior investigator.
The investigators had performed similar distraction osteogenesis procedures in children born with small jawbones and wondered about the feasibility of using the procedure in adults with oral cancer. They began by testing the procedure in animals and have tried it in patients with oral cancer who were not appropriate candidates for the fibula transfer surgery. They also have used this method in patients with benign tumors and in those who had experienced a trauma.
Patients who have undergone distraction osteogenesis compare the discomfort level to that of wearing orthodontic braces. The devices used for the stretching procedure are submerged and not visible.
The next step in this research is to study distraction osteogenesis with radiation therapy in larger animals and compare the results with those in animals that undergo distraction osteogenesis without radiation therapy.
