Quantification of retropalatal region in obstructive sleep apnea

Flexible optic laryngoscopy (FOL) allows us to visualize the obstructive sleep apnea (OSA)-related airway passages. However, objective data presenting evidence of OSA through this perspective are lacking. The aim of this study was to quantify the surface area of the retropalatal region in control subjects and OSA patients utilizing FOL images. This was a prospective, case-control study. The study was performed at the otolaryngology department of a university hospital.

Sixty-seven OSA patients in group 1 and 87 patients with no complaints of OSA in group 2 were evaluated. Retropalatal region photographs were captured at the base of uvula through endoscopic images. The retropalatal surface area (RPSA) was measured using AutoCAD. Groups 1 and 2 RPSA measurements were analyzed. The RPSA measurements of subgroups in group 1 were analyzed to document severity of OSA.

Mean RPSA measurements in group 1 was 73.21 (SD, 31.99), and that in group 2 was 129.31 (SD, 26.54), respectively. Retropalatal surface area is significantly larger in group 2 when compared with group 1 (P = 0.0001). Twenty-four patients had mild (mean respiratory disturbance index [RDI], 10.83 [SD, 3.63], 26 had moderate (mean RDI, 20.9 [SD, 4.14]), and 17 had severe OSA (mean RDI, 52.13 [SD, 17.24]) in group 1. The mean RPSA measurements are 72.48 (SD, 28.9) in mild subgroup, 73.88 (SD, 30.5) in moderate subgroup, and 73.22 (SD, 39.59) in severe subgroup, showing no evidence of correlation between the severity OSA and RPSA measurements.

The RPSA measurements are significantly larger in control subjects (group 2) when compared with OSA patients (group 1). This might implicate that RPSA measurements through FOL examination can be a predictor of OSA when screening patients.