The implication of sleep position in the evaluation of surgical outcomes in obstructive sleep apnea

Abstract

Objective: To investigate the effect of sleep position on surgical outcomes in obstructive sleep apnea (OSA).

Study Design: Retrospective review of 69 consecutive patients.

Subjects and Methods: Preoperative and postoperative polysomnographic data and Epworth sleepiness scale were obtained. Patients were categorized into success, response, no response, and failure groups according to apnea-hypopnea index (AHI) after uvulopalatopharyngoplasty. Proportions of supine or lateral position and AHI of each position were evaluated. Position-corrected AHI was developed in order to eliminate the effect of sleep position.

Results: Preoperative proportion of supine position in the failure group (n = 26) was 41.3 percent, which was the lowest among four groups (P = 0.010), and increased to 60.8 percent postoperatively (P = 0.028). Twenty-two (84.6%) among the failure group had supine position dependency. Regrouped by position-corrected AHI, 15 patients moved into different groups. Postoperative AHI showed positive correlation with increased supine position when BMI was controlled (r = 0.515, P = 0.006).

Conclusion: Without appropriate correction based on the change of sleep position, the fluctuation of sleep position in each polysomnography might confound surgical outcomes in OSA patients. Thus, it is a substantial issue how to control or reflect the positional effect on AHI when treatment results are evaluated.