Three-dimensional evaluation of upper airway changes following maxillomandibular surgery for Class III deformity with or without advancement genioplasty.

This retrospective study was performed to evaluate the effect of maxillomandibular surgery on upper airway volumes and hyoid bone positioning in patients with Class III skeletal deformities, treated with maxillary advancement and mandibular setback, with/without a concomitant genioplasty. The study involved 43 patients, divided into two groups: BiMax (bimaxillary surgery with Le Fort I osteotomy and mandibular setback) and BiMax + G (the same surgery with an advancement genioplasty). Changes in nasopharynx, oropharynx, and hypopharynx volumes and position of the hyoid bone were assessed using pre- and postoperative CBCT scans. The data were analysed using t-tests, the Mann-Whitney U-test, and the Wilcoxon signed rank test. The patients in both groups showed a significant increase in nasopharyngeal volume post-surgery (BiMax, P = 0.009; BiMax + G, P = 0.001); however, the change in volume did not differ significantly between the groups. Furthermore, the hypopharyngeal volume increased significantly in the BiMax + G group (P = 0.025), but there was no statistically significant difference in volume change between the groups. There was no statistically significant between-group difference in the change in oropharyngeal or total pharyngeal volume. However, a significant difference was observed in the change in H-RGn distance between the groups (P = 0.021), indicating a differential effect on this hyoid-related parameter. Further exploration of the effects of genioplasty on the upper airway is necessary in future studies.