A volumetric threshold and age-dependent remodeling are associated with residual obstructive sleep apnea after adenotonsillectomy in children

BACKGROUND: Adenotonsillectomy is first-line treatment for pediatric obstructive sleep apnea (OSA), yet residual disease persists in a notable subset of children. Traditional preoperative assessments reflect patient characteristics rather than airway anatomy, while prior cone-beam CT (CBCT) studies required extra research-only scans. AIMS/OBJECTIVES: We evaluated whether postoperative CBCT-measured upper-airway volume distinguishes complete OSA resolution from residual disease, and assessed age-related postoperative soft-tissue remodeling. MATERIALS AND METHODS: This single-center retrospective STROBE-compliant cohort enrolled 238 children aged 3-10 years with PSG-confirmed OSA who underwent coblation adenotonsillectomy, with clinically indicated pre- and 3-month postoperative CBCT. Postoperative OAHI <1 defined complete resolution, and OAHI ≥5 defined residual OSA. ROC and multivariable logistic regression analyses were performed. RESULTS: Mean OAHI decreased from 16.8 to 5.4 events/h (*p*<0.001). Complete resolution was achieved in 63.4% patients. The optimal postoperative airway volume cutoff was 10.5 cm³ (AUC=0.89). Postoperative volume <10.5 cm³, adenoid regrowth, high preoperative OAHI, younger age (3.0-3.9 years), and tongue-base hypertrophy were independent predictors of residual OSA. CONCLUSIONS AND SIGNIFICANCE: Postoperative upper-airway volume of 10.5 cm³ effectively stratifies residual OSA risk. Young age independently predicts persistent disease, likely due to incomplete soft tissue remodeling. This CBCT-based stratification uses clinically acquired imaging without extra radiation exposure.