Endoscopic upper airway evaluation in obstructive sleep apnea: Mueller's maneuver versus simulation of snoring

This study aimed to compare fiberoptic nasopharyngoscopy during Mueller's maneuver (FNMM) with fiberoptic nasopharyngoscopy with simulation of snoring (FNSS) for upper airway (UA) assessment in patients with obstructive sleep apnea and hypopnea syndrome. We also investigated the relationship between daytime endoscopic examinations and nocturnal pressure measurements. We conducted a prospective, case-series study at Peking Union Medical College Hospital. All patients were evaluated by daytime FNMM and FNSS. The retropalatal and retroglossal regions were continuously video recorded during quiet breathing, FNMM, and FNSS. We calculated the narrowing rate and determined the level of obstruction and pattern of collapse (lateral, anterior-posterior, or concentric). Patients also underwent nocturnal pressure measurements to identify obstruction sites. Ninety-two patients were enrolled. FNMM and FNSS detected retropalatal obstruction in every case. Fifty-six and 38 patients had retroglossal obstruction detected by FNMM and FNSS, respectively. There was diagnostic agreement between FNMM and FNSS in 72 patients when diagnosing retroglossal obstruction, but the patterns of collapse were different using each technique. Pressure measurements showed that lower apnea and hypopnea index (AHI) and the proportion of lower AHI were significantly lower in the isolated retropalatal obstruction group than in the combined obstruction group diagnosed with either FNMM or FNSS (p < 0.01). Daytime FNMM and FNSS are reliable for evaluating the level of obstruction and pattern of UA collapse, and correlate with sleep study findings. FNSS may provide some different information regarding patterns of collapse and retroglossal obstruction from FNMM. Both techniques are helpful for determining surgical strategies.