Condylar resorption after bicortical screw fixation of mandibular advancement

This study evaluated long-term condylar resorption after mandibular advancements stabilized with bicortical screws.

One hundred mandibular deficiency patients who underwent bilateral sagittal split osteotomies (BSSO) fixed with three bicortical screws per side, and who were followed for a minimum of 1 year with complete radiographic records, were evaluated. Preoperative panoramic radiographs were traced and superimposed as a best fit over long-term panoramic radiographs. Cephalometric tracings were available on all patients preoperatively, immediately after surgery, 6 to 8 weeks after surgery, and at long term after surgery. These tracings were used to show the amount of the initial advancement and any changes that occurred between 6 to 8 weeks and long term in those patients who exhibited 10% or greater changes in their condylar height. Preoperative temporomandibular joint signs and symptoms were recorded on all patients before surgery and at 6 months after surgery.

There were 10 patients who had 10% or greater vertical change in their condyles; all changes were unilateral. Large advancement (P > .009) and preoperative temporomandibular joint symptoms (P > .01) statistically correlated with long-term postoperative condylar resorption. There was not a direct correlation between the amount of vertical change in the condyle and the amount of relapse. There was an improvement in temporomandibular joint symptoms for the group as a whole and in the group with condylar resorption.

Patients with large advancements and preoperative temporomandibular joint symptoms appear to be at risk for condylar resorption. These results are similar to those from other studies in which rigid fixation or miniplates were used for cases of mandibular advancement.