THE STABILITY OF DOUBLE JAW SURGERY - A COMPARISON OF RIGID VERSUS WIRE FIXATION

The subjects of this study were 35 patients who underwent simultaneous surgery for superior repositioning of the maxilla and advancement of the mandible. They were studied cephalometrically for a comparison of the posturgical stability of two commonly used fixation techniques: (1) rigid fixation with bone plates and (2) skeletal-wire fixation. One surgeon performed the operations on all 35 patients, and both groups were studied for an average of 15 months after surgery. Results showed that, although the maxilla remained relatively stable after surgery with both fixation techniques, rigid fixation tended to improve stability, primarily by eliminating relapse in excess of 2 mm. Mandibular stability was much greater with rigid fixation: the amount of relapse of the horizontal projection of B point with this method was 6%, while in the skeletal-wire sample it was 26%. Increased rotational stability between the proximal and distal segments of the mandible appeared to be a major factor in the improved overall stability of the rigid-fixation sample. The amount of mandibular relapse was found to be correlated to the amount of advancement in the wire-fixation sample, but not in the rigid-fixation sample.