Effects of mandibular setback surgery using the surgery-first approach versus conventional orthognathic approach on upper airway change and sleep quality.

Objectives: To compare the effects of mandibular setback surgery on the upper airway and sleep quality using two approaches: the surgery-first approach (SFA) and the conventional orthognathic approach (COA).

Materials and methods: A prospective, comparative clinical study was conducted in 20 patients, with 10 in each group undergoing isolated mandibular setback surgery. Three-dimensional upper airway analysis using cone-beam computed tomography and sleep quality assessments through questionnaires and sleep studies were performed preoperatively (T0), within 1 month postoperatively (T1), and six months postoperatively (T2).

Results: The SFA group demonstrated greater mandibular setback and rotational changes compared to the COA group. Both groups exhibited postoperative reductions in airway volume and minimum cross-sectional area, with no significant intergroup differences. Significant differences in the change in airway length in the upper airway segment (0.9 ± 1.0 mm for SFA vs. -1.2 ± 3.4 mm for COA, P = 0.002) and total airway length (3.3 ± 1.8 mm for SFA vs. -0.1 ± 2.3 mm for COA, P < 0.001) were observed at T2 compared to the preoperative period. Subjective and objective sleep parameters were comparable between the groups. Objective sleep quality initially worsened but improved over time.

Conclusions: Isolated mandibular setback surgery, whether performed using SFA or COA, resulted in comparable changes in upper airway dimensions and sleep quality.

Clinical relevance: The choice between SFA and COA for isolated mandibular setback surgery does not significantly influence surgical decision-making regarding upper airway changes and sleep quality.