Changes in upper-airway dimensions and sleep-related respiratory parameters after advancement genioplasty for mandibular retrognathia: a preliminary observational study

To explore postoperative changes in upper airway morphology and sleep respiratory function following isolated horizontal advancement genioplasty for skeletal Class II mandibular retrognathia with chin retrusion, and provide preliminary reference for individualized surgical design balancing facial aesthetics and respiratory function. This single-center retrospective preliminary observational cohort consecutively recruited 26 eligible patients receiving isolated genioplasty between June 2025 and January 2026. All participants completed standardized CBCT upper airway measurement and home sleep apnea testing (HSAT) at baseline and the unified 6-month postoperative follow-up. Primary airway indicators included segmented airway volumes and oropharyngeal minimum cross-sectional area; sleep parameters contained AHI (calculated using total recording time rather than total sleep time), arterial oxygen saturation metrics, snoring score and ESS. Paired samples t-test and Pearson correlation analysis were applied for statistical comparison and correlation exploration. All upper airway volumetric and linear indicators increased at 6 months postoperatively, yet no statistically significant differences between preoperative and postoperative measurements were detected (all P > 0.05).All sleep respiratory parameters showed substantial statistically significant improvements (all P < 0.001): the mean AHI dropped from 13.35 ± 2.59 events/h to 6.18 ± 1.79 events/h, accompanied by elevated blood oxygen levels and shortened hypoxic duration. Pearson analysis demonstrated that horizontal chin advancement had a weak significant positive correlation with total airway volume change ( r = 0.412, P = 0.036), a borderline correlation with oropharyngeal minimum cross-sectional area ( r = 0.387, P = 0.051), and a strong positive correlation with AHI reduction ( r = 0.682, P < 0.001). Within this small uncontrolled 6-month cohort, isolated horizontal advancement genioplasty was associated with a nonsignificant trend toward upper-airway enlargement and significant improvements in HSAT-derived respiratory parameters and sleep-related symptoms.