Effect of supine and upright positions on airway dimensions in patients with obstructive sleep apnea

Abstract

Aim: The aim of the study was to assess the effect of supine vs upright imaging positions on airway dimensions in patients with obstructive sleep apnea (OSA).

Materials and methods: This retrospective study included three-dimensional (3D) data of 30 subjects diagnosed with OSA. Patients’ ages ranged from 26 to 60 years (35.7 ± 2.3 years). Subjects were scanned with a low-dose multiplanar CT scanner in a supine position using X-vision EX, (Toshiba Medical Systems, Otawara-Shi, Japan) at a voxel size of 0.4 mm and a second scan in an upright position using iCAT CBCT scanner (Imaging Sciences International, Hartfield, PA) at the same voxel size. Airway volume was measured at the level of the nasal cavity, nasopharynx, oropharynx, and hypopharynx using Dolphin imaging software (version 11.5; Patterson Dental Supply, Chatsworth, CA). The differences in the measurements in both positions were compared using Student’s t-test and p ≤ 0.05 was considered statistically significant.

Results: Significant statistical differences were reported between the measurements at the two positions. The nasopharynx and oropharynx area were significantly less when measured at the supine position. The airway volume measured at the nasal cavity and hypopharynx did not show significant differences between both positions.

Conclusion: The patient’s position during the imaging session significantly affects the airway measurements. Airway volume measurement recorded when patient scanned in supine position shows less values than those recorded with upright scanning position.