title: 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).
  
  
  METHODS
  Retrospective review of 69 consecutive patients.
  
  
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Bundang-Gu, Seongnam, Korea.
authors.forename: Chul Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Shin
authors.forename: Doo Hee
authors.initials: DH
authors.lastname: Han
authors.forename: Ji-Hun
authors.initials: JH
authors.lastname: Mo
authors.forename: In-Young
authors.initials: IY
authors.lastname: Yoon
authors.forename: Seockhoon
authors.initials: S
authors.lastname: Chung
authors.forename: Hyo Geun
authors.initials: HG
authors.lastname: Choi
authors.forename: Jeong-Whun
authors.initials: JW
authors.lastname: Kim