Change of TMJ Space Volume After Mandibular Setback BSSRO With Intended Manual Condyle Positioning in Severe Facial Asymmetric Patients.

PURPOSE

This study aimed to quantitatively analyze temporomandibular joint (TMJ) space volume changes before and after bilateral sagittal split ramus osteotomy (BSSRO) with intended manual condyle positioning in patients with severe facial asymmetry.

METHODS

A retrospective study was conducted, including 20 patients with facial asymmetry (menton deviation >8 mm) who underwent BSSRO with intended manual condyle positioning at a single institution. Cone beam computed tomography (CBCT) images were obtained preoperatively (T0), 2 days postoperatively (T1), and 6 months postoperatively (T2). TMJ space volumes on the deviation side (DS) and non deviation side (NDS) were measured at each time point. Changes in TMJ space volume were analyzed over time and compared between the DS and NDS using appropriate statistical methods.

RESULTS

Both the DS and NDS exhibited an increasing trend in TMJ space volume from T0 to T1, followed by a reduction at T2, approaching levels similar to T0. The change in volume from T0 to T1 was more pronounced on the DS compared with the NDS.

CONCLUSIONS

In patients with severe facial asymmetry undergoing BSSRO, there is a tendency for the TMJ space to increase initially. However, incorporating manual condylar positioning to achieve a stable condyle position results in the TMJ space returning to pre-surgery levels by 6 months postoperatively. These findings suggest that intended manual condyle positioning may help maintain proper TMJ function following BSSRO in patients with severe facial asymmetry.