Effect of Muller maneuver on upper airway characteristics and surrounding structures in patients with obstructive...

The Muller maneuver (MM) collapses the upper airway and mimics apneic events during sleep. This study aimed to assess the effect of MM on the upper airway (UA) and surrounding structures of patients with OSA using cone-beam computed tomography (CBCT). This prospective study of 18 moderate-to-severe OSA patients included two CBCT scans, one during gentle breathing and another while performing MM, with standardized head and neck positioning. UA, soft tissue, and hyoid bone were analyzed using linear, area, and volumetric measurements with OnDemand 3D software version 10.0.1 (1008 measurements). Paired t-tests, Wilcoxon signed-rank tests, Marginal Homogeneity tests, and two-way repeated-measures ANOVA were performed using SPSS version 27 software. Effect sizes were calculated using Cohen's d. MM statistically significantly decreased the following airway parameters: minimum anterior-posterior (mAP) of nasopharynx (6.41% (P = 0.048)), mAP-oropharynx (38.81% (P = 0.006)), minimum transverse(mT) of oropharynx (38.88% (P = 0.006)), minimum cross-sectional area(mCSA) of oropharynx (42.02%; P = 0.011), volume(V) of oropharynx (27.41%; P = 0.002), mAP-hypopharynx (19.77%;P = 0.039) and mCSA-hypopharynx (11.77%;P = 0.048), V-UA (11.76%;P = 0.048) and minimum axial area (39.01%; P = 0.007). MM also resulted in significant vertical hyoid bone changes and soft tissue length (P = 0.001, P = 0.016, respectively). Effect size analysis demonstrated predominantly moderate-to-large effects across variables, particularly for hyoid bone displacement and oropharyngeal airway narrowing, indicating that the observed changes were not only statistically significant but also clinically meaningful. This noninvasive, low-cost approach, provides comprehensive evaluation of the UA and surrounding structures. It also offers functional insight by capturing airway configuration under negative pressure conditions, enabling a more dynamic assessment of airway behavior and collapsibility.