Correlation Study of Ramus-Preserving Mandibular Angle Osteotomy and Lower Facial Soft Tissue Sagging: A Retrospective Analysis of 104 Cases.

Abstract

This study investigates the impact of ramus-sparing mandibular angle ostectomy on mandibular contour morphology and lower facial soft tissue laxity. A total of 104 patients who underwent surgery at Shanghai Ninth People's Hospital affiliated with Shanghai Jiao Tong University School of Medicine between January 2018 and December 2023 were included. Comprehensive three-dimensional facial data acquisition using 3DMD imaging systems and computed tomography scans were performed preoperatively and at 6-month follow-up. Quantitative assessments included: 1) comparative analysis of hard and soft tissue ramus heights, 2) Merz aesthetic scale evaluation, and 3) cervical-mental angle measurements. No statistically significant differences were observed in ramus height measurements between osseous and soft tissue components (p>0.05), demonstrating proportional soft tissue adaptation to skeletal reduction (mean bone resection: 17.1±4.5 mm vs soft tissue change: 15.9±4.3 mm). Both Merz scale assessments (preoperative: 1.94 vs postoperative: 1.79) and cervical-mental angles (preoperative: 114.62° vs postoperative: 111.52°) showed no statistically significant differences at 6-month follow-up (p>0.05). The ramus-sparing mandibular angle ostectomy effectively contours the mandible without inducing significant lower facial soft tissue relaxation in short-term evaluation, demonstrating its clinical reliability for facial aesthetic surgery.