Sequential Changes in Pharyngeal Airway Dimensions After Mandibular Setback Surgery and Its Correlation With Postsurgical Stability in Patients With Mandibular Prognathism

Purpose: This study aimed to evaluate the sequential changes in the pharyngeal airway dimensions after mandibular setback surgery and to verify its correlation with postsurgical mandibular stability in patients with mandibular prognathism. Patients and methods: This retrospective study included 28 patients with mandibular prognathism who underwent surgical orthodontic treatment and isolated mandibular setback surgery. Patients who had cone-beam computed tomography before surgery, immediately after surgery, at short-term follow-up (11.8 +/- 5.1 months), and long-term follow-up (43.0 +/- 13.1 months) were included. Airway dimensions, including distance, minimum cross-sectional area, and airway volume, were measured to evaluate the changes following mandibular setback surgery. With the measurements of postsurgical mandibular relapse, the relationship between sequential changes in airway dimensions and the mandible was verified using correlation analysis. Results: Airway dimensions decreased immediately after mandibular setback surgery. The decreased airway dimensions recovered during short-term follow-up and maintained to the long-term follow-up. The mandible was set back 7.7 +/- 5.1 mm at pogonion immediately after surgery. Postsurgical skeletal relapse was 1.1 mm at pogonion during short-term follow-up. During long-term follow-up, the mandible moved 0.4 mm anteriorly, which was about 50% of the changes during short-term follow-up. Statistically significant correlations were found between the sequential changes in airway dimensions and the postsurgical skeletal relapse. Conclusion: The decreased airway dimensions following mandibular setback surgery recovered during short-term follow-up and maintained to the long-term follow-up. Dimensional recovery of the pharyngeal airway was correlated with postsurgical skeletal relapse during the 1-year follow-up period. (C) 2021 The American Association of Oral and Maxillofacial Surgeons.