Advancement genioplasty as a compensatory measure for mandibular setback-induced airway volume reduction in skeletal class III deformities: a 3D analysis of long-term outcomes

Airway volume changes induced by orthognathic surgery might impair patients’ sleep quality. Yet, the long-term impact of bimaxillary surgery with advancement genioplasty on airway volume of patients with skeletal class III deformities and its association with snoring remains elucidated. The study aimed to analyze changes in upper airway volume and other airway parameters after bimaxillary surgery, with or without advancement genioplasty, and to explore the association between these surgical procedures and postoperative changes in snoring. A total of 31 patients were enrolled and divided into two groups: Group 1 (Le fort I osteotomy and mandibular setback), Group 2 (Le fort I osteotomy, mandibular setback, and advancement genioplasty). Airway parameters were calculated at three time points using three-dimensional airway reconstruction based on CT. Snoring was assessed using the Chinese version of Snore Outcomes Survey (C-SOS). No significant differences in Body mass index (BMI) and amount of bimaxillary movement were observed between two groups. The total pharyngeal airway volume (TPV) in Group 2 showed a change of -2741.50 ± 5883.63 mm3 from pre-operation to one year after surgery, while that of Group 1 was − 4344.65 ± 7542.94 mm3 (P = 0.005). Particularly, the hypopharyngeal volume (HPV) reduced even more in Group1 than in Group 2 (P < 0.001). Correspondingly, the C-SOS score of Group 2 was 62.22 ± 3.80, better than Group 1 (60.5 ± 4.82) at the one-year postoperative follow-up. Advancement genioplasty effectively compensates for mandibular setback-induced airway volume reduction which supports its inclusion in surgical planning to improve postsurgical respiratory outcomes.