Evaluation of post-operative skeletal stability after sagittal split ramus osteotomy and contralateral intraoral vertical ramus osteotomy in asymmetric mandibular setback

Objectives: This study aims to evaluate the stability of the sagittal split ramus osteotomy (SSRO) and contralateral intraoral vertical ramus osteotomy (IVRO) surgery with resorbable fixation. Patients and Methods: A total of 16 patients who underwent orthognathic surgery using SSRO with contralateral IVRO approach and resorbable fixation for the treatment of facial asymmetry at the Department of Oral and Maxillofacial Surgery, Gangneung-Wonju National University Dental Hospital from 2003 to 2023 were included. Lateral cephalogram images that were taken at the time point of preoperative (T0), immediately postoperative (T1) and one year after surgery (T2) were measured. The B point position changes were statistically analyzed. Results: The sella-nasion-B point (SNB) angle and vertical reference line to B point (VRL-B) value showed significant differences between T0 and T1 (P<0.001), as well as between T0 and T2 (P<0.001), but no significant differences were found between T1 and T2 (SNB angle; P=0.460, VRL-B; P=0.638). The HRL-B value showed significant difference between T0 and T2 (P=0.008), but not between T0 and T1 (P=0.069) or between T1 and T2 (P=0.191). Conclusion: In the present study, the combined SSRO with contralateral IVRO approach appears to offer reliable postoperative stability in asymmetric mandibular setback.