OBJECTIVETo evaluate the clinical value of localization of upper airway obstructive site with pressure measurements and Friedman staging system in preoperative upper airway reconstructive surgery for obstructive sleep apnea-hypopnea syndrome (OSAHS), and to evaluate the value of Friedman staging system in predicting the upper airway obstructive site.

METHODSOne hundred and three patients with snoring, daytime sleepiness diagnosed as OSAHS by polysomnography were first classified using Friedman staging system, and then examined using whole night recording, including airway continuous pressure measurements (Apnea Graph, AG). AG transducer catheter containing two pressure and two temperature sensors used for obstruction site determination and detection of apnea events during sleep. Obstructive sites were divided into upper (retropalatal region) or lower level (retroglossal region). Using constituent ratio to reflect the obstructive proportion of different levels so as to find the correlation between Friedman staging system and localization of upper airway obstructive site with pressure measurements performed during sleep, and to evaluate the clinical value of Friedman staging system in predicting the severity of OSAHS.

RESULTSThere was statistically significant difference in the constituent ratio of retroglossal obstruction determined by AG, according to Friedman staging system, Friedman tongue position (FTP) and tonsil size grading (F = 13.876, 7.655, 10.207 respectively, P < 0.05). The constituent ratio of retroglossal obstruction between stage IV and I, II, III (P < 0.01) was significantly different. With the increasing of Friedman staging, the constituent ratio of retroglossal obstruction had the tendency of increasing. The constituent ratio of retroglossal obstruction between FTP grade 2 and grade 3, grade 4 (P < 0.05) was significantly different. With the increasing of FTP grading, the constituent ratio of retroglossal obstruction had the tendency of increasing. The constituent ratio of retroglossal obstruction between the Friedman tonsil size grade 4 and grade 1, grade 3 (P < 0.01), grade 2 (P < 0.05) was significantly different.

CONCLUSIONSFriedman staging system, in particular the FTP grading, had a correlation with upper airway pressure measurements (AG) in determination of the lower level of upper airway obstructive site, especially the retroglossal region, which could predict the main localization of upper airway obstructive site identified by upper airway pressure measurements during the sleep.