Comparison of condylar displacement after sagittal split ramus osteotomy depending on the glenoid fossa depth

This study aimed to evaluate the relationship between postoperative condylar displacement (PCD) after sagittal split ramus osteotomy (SSRO) and the glenoid fossa depth. A total of 29 patients who underwent computed tomography (CT) before surgery (T0), immediately after (T1), and 6 months after (T2) surgery were studied. The fossa depth was measured, and the amount of displaced condylar center and axis were evaluated on CT at T0, T1, and T2 using three-dimensional analysis software. PCD and the fossa depth relationship was investigated by Pearson's correlation analysis. The fossa depth varied from 3.9 mm to 12.0 mm, and the mean value was 8.15 ± 1.60 mm. The condylar center was displaced by 1.12 ± 0.66 mm at T1 compared with it at T0. The amount of displaced condylar center negatively correlated with the fossa depth (r = -0.424, p = 0.001). The displacement of the condylar center between T0 and T2 was 0.85 ± 0.51 mm. The amount of condylar center displacement between T0 and T1 showed a positive correlation with it between T0 and T2 (r = 0.481, p < 0.001). In conclusion, more attention is needed in patients with small fossa depth during condylar repositioning after SSRO and postoperative management to minimize complications.