Pharyngeal constrictor muscle fatty change may contribute to obstructive sleep apnea-hypopnea syndrome: a prospective observational study.

CONCLUSIONS: Pharyngeal constrictor muscle injury and fatty changes may play important roles in the pathogenesis and progression of OSAHS.

OBJECTIVE: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a respiratory disorder caused by upper airway obstruction during sleep. The primary objectives of this study were to determine the ultrastructural characteristics of the pharyngeal constrictor muscle in patients with OSAHS.

METHODS: A pharyngeal constrictor muscle specimen was collected from all subjects. The muscle cell ultrastructure was observed under electron microscopy.

RESULTS: Eighteen male patients with OSAHS (OSAHS group) and 10 male body mass index-matched patients with chronic tonsillitis (control group) were enrolled in this study. All patients were obese adults. The apnea-hypopnea index (41.22 ± 17.29 vs 2.30 ± 1.10 events/h) was significantly higher and the lowest arterial oxygen saturation (76.00 ± 8.57% vs 97.00 ± 2.00%) was significantly lower in the OSAHS group than in the control group (both p < 0.001). Myofibril disorder, mitochondrial edema, and intramyocellular lipid droplets were observed in patients with OSAHS. There was a significant correlation between the number of lipid droplets and the apnea-hypopnea index.