Effects of Upper Airway Surgery on Daytime Sleepiness in Nonobese Patients with Obstructive Sleep Apnea/Hypopnea Syndrome

Introduction: The aim of this study was to evaluate the effects of upper airway surgery on daytime sleepiness in nonobese patients with obstructive sleep apnea/hypopnea syndrome (OSA). Methods: This retrospective study included 121 consecutive adult nonobese patients with OSA from a tertiary academic medical center. Patients with OSA who refused continuous positive airway pressure therapy, or in whom it was unsuccessful, and then underwent OSA surgery were enrolled. Evaluations of excessive daytime sleepiness using the Epworth Sleepiness Scale (ESS) and major parameters of objective full-night polysomnography were collected preoperatively and at least 3 months postoperatively. Statistical analysis was performed using the Wilcoxon signed rank test and Wilcoxon rank sum test. Results: When pre- and postoperative ESS and polysomnographic parameters were compared in all patients, ESS scores, apnea/hypopnea index, and snoring index showed statistically significant improvements (P = .007, P < .001, and P < .001, respectively). When patients were classified into mild, moderate, and severe OSA groups, snoring index had statistically significant improvements in all 3 groups, and apnea/hypopnea index had statistically significant decreases in the moderate and severe OSA groups. Although reductions in ESS scores were found in all 3 groups, the most statistically significant improvement was noted only in the severe OSA group. Conclusions: OSA surgery can improve daytime sleepiness in nonobese patients with OSA, especially for patients with severe OSA. This study elucidates the effects of OSA surgery on daytime sleepiness by excluding the major confounding factor of obesity. This study adds to the literature on the effects of upper airway surgery for nonobese patients with OSA on daytime quality of life.