Gender differences in morphological and functional outcomes after mandibular setback surgery

Purpose

The aim of this study was to examine and compare morphological and functional outcomes after either isolated mandibular setback or bimaxillary surgery in males and females.

Materials and methods

A retrospective study was done on 52 patients, in whom surgical correction for mandibular prognathism was performed either by isolated mandibular setback (30 cases) or by bimaxillary surgery (22 cases). Morphological changes were studied using cephalograms and functional changes studied using impulse oscillometry (IOS) taken before surgery (T0), 3 months (T1) and 1 year after surgery (T2). Also 3% oxygen desaturation index (ODI) was measured at T0 and T2.

Result

Posterior airway space decreased significantly in both groups and both sexes but more so in males after mandibular setback surgery and in females after bimaxillary surgery. Changes in supine R20 (central airway resistance at 20 Hz) and supine R5 (total airway resistance at 5 Hz) in IOS statistically significantly increased in the period T0–T1 in males compared with females after mandibular setback surgery (p < 0.05).

Conclusion

Gender dimorphism is present according to morphological and functional outcomes, with males at a higher risk for obstructive sleep apnea (OSA) after mandibular setback surgery and females after bimaxillary surgery; however, compensatory changes act as a barrier against this.