Assessment of condylar position following bilateral sagittal split ramus osteotomy with wire fixation or rigid fixation.

In this study, 53 patients who underwent a bilateral sagittal split ramus osteotomy to advance the mandible were examined radiographically to assess condylar position presurgically, postsurgically, and posttreatment. Subjects were separated into two groups, 29 patients who received wire fixation and 24 who received rigid internal fixation. Condylar position changes were measured on tracings of submentovertex and transcranial radiographs at the time periods mentioned. Differences in condylar position were evaluated in two defined time intervals--T1, presurgical to postsurgical, and T2, postsurgical to posttreatment. Right and left sides were evaluated independently. No correlation between amount of advancement and condylar position change was identified within or between the fixation groups at T1 and T2. No correlation between change in mandibular plane angle and change in condylar position was identified within or between the groups at T1 and T2. Statistically significant differences were identified between the fixation groups in the degree of condylar change measured on the tracings of both submentovertex and transcranial radiographs both right and left sides, at time T1. There was also a significant difference in the change in mandibular plane angle at T1 between the fixation groups. It appears from this study that use of rigid internal fixation following bilateral sagittal split ramus osteotomy results in a statistically significantly greater condylar displacement than does wire fixation. Further research is required to determine whether these changes in condylar position are clinically significant.