Comprehensive 3D Analysis of Condyle After BSSRO in Surgery-First Approach Among Mandibular Prognathism Patients With...

This study aimed to comprehensively analyze changes in condylar volume and position before and after bilateral sagittal split ramus osteotomy (BSSRO) in mandibular prognathism patients with and without asymmetry in the Surgery-First Approach (SFA).

A retrospective study included 10 patients in the asymmetry group and 13 in the symmetry group who underwent BSSRO in SFA. Computed tomography scans were collected at preoperative (T0) and 6 months postoperative (T1) to measure the 3D condylar volume (CV) and condylar displacement and rotation. Measurements on the deviated side (DS) and nondeviated side (NDS) were performed at each time point. Three-dimensional changes of condylar volume, displacement distance, and rotation angle were analyzed over time and compared between sides and groups using appropriate statistical methods.

Significant CV reduction was observed on both sides in the symmetry group after surgery. The center of the condylar head moved anteriorly in the symmetry group postoperatively. Meanwhile, it moved significantly forward and laterally on DS and anteriorly on NDS in the asymmetry group after surgery. The long axis of the condylar head rotated anteriorly and inferiorly on both sides and in both groups in the sagittal and coronal planes. In the horizontal plane, outward rotation on the DS and inward rotation on the NDS were identified in the asymmetry group.

In patients with severe facial asymmetry undergoing BSSRO, baseline condylar dysplasia is associated with greater postoperative condylar resorption. The pattern of condylar head displacement and rotation in our study resembled OFA results rather than those of other SFA studies. These findings suggest that SFA in our center may produce a similar impact on condylar remodeling as OFA.