Condylar and disc positions after sagittal split ramus osteotomy with and without Le Fort I osteotomy.

Purpose: The purpose of this study is to examine the changes in temporomandibular joint (TMJ) morphology and clinical symptoms after sagittal split ramus osteotomy (SSRO) with and without a Le Fort I osteotomy.

Subjects And Methods: Of 45 Japanese patients with mandibular prognathism, 23 underwent SSRO and 22 underwent SSRO in combination with a Le Fort I osteotomy. The TMJ symptoms and joint morphology, including disc tissue, were assessed preoperatively and postoperatively by magnetic resonance imaging (MRI) and axial cephalography.

Results: There were significant differences between pre- and postoperative horizontal changes in the condylar long axis on the right side in the group undergoing SSRO (sagittal split ramus osteotomy) alone. However, there were no other significant differences in pre- and postoperative measurements in this group as compared with the group receiving SSRO plus Le Fort I osteotomy, and the preoperative disc position could not be changed in either group.

Conclusion: These results suggest that SSRO, either with or without Le Fort I osteotomy, could not change the preoperative disc position or correct anterior disc displacement, although these procedures did improve the symptoms associated with TMJ dysfunction.