Roentgenographic dimensions of the upper airway in snoring patients with and without obstructive sleep apnea

The purpose of this study was to examine whether a simple test, such as routine roentgenographic views of the upper airway, is useful in identifying anatomic narrowing of the airway in patients with sleep apnea. To accomplish this, we prospectively studied a group of 117 patients (95 male and 22 female subjects) referred for evaluation of heavy snoring and possible obstructive sleep apnea. All patients had full nocturnal polysomnography, including measurements of snoring. Lateral view of the airway obtained after swallowing contrast material was used to measure pharyngeal diameters at three sites along the airway. All measurements were performed with the patients standing and supine. We used three different definitions of sleep apnea (apnea/hypopnea index of 10, 20, and 40), and compared airway diameters between the apneic and nonapneic snorers. Only when sleep apnea was defined as greater than 40 apneas plus hypopneas per hour of sleep was there a significant difference in airway diameter at the tip of the palate and 1 cm distal to it between apneic and nonapneic snorers. Both groups of patients demonstrated a significant reduction in the retropalatal distance on assumption of the supine posture. Stepwise, forward, multiple linear regression analysis showed that the retropalatal distance and airway diameter at the tip of the palate and 1 cm distal to it were significant predictors of snoring, but not apnea. We conclude that (1) airway diameters account for some of the variability in snoring, and (2) they do not differentiate between apneic and nonapneic snorers.