Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults

Abstract

Study objectives: First, to compare the upper airway's anatomic and aerodynamic characteristics of the edentulous older adults who experience mild, moderate, and severe obstructive sleep apnea (OSA). Second, to examine the correlation between the severity of OSA and the anatomic and aerodynamic characteristic(s) of the upper airway in these edentulous individuals.

Methods: NewTom5G cone beam computed tomography scans of 58 edentulous individuals with mild, moderate, and severe OSA were included in this analysis. 1) Computational models of the upper airway were reconstructed based on cone beam computed tomography images and the anatomical and aerodynamic characteristics of the upper airway were examined by an observer blind to OSA severity. 2) Pearson correlation analysis was used to determine the correlation between apnea-hypopnea index and the anatomic and aerodynamic characteristics of the upper airway.

Results: Compared with edentulous patients with mild and moderate OSA, those with severe OSA have a more hourglass-shaped upper airway. The severity of OSA, namely, apnea-hypopnea index, was significantly correlated with the length, shape, and minimum cross-sectional area of the upper airway. During inspiration, the mean velocity of the airflow within the upper airway of the edentulous patients with severe OSA was higher than that of patients with mild and moderate OSA. During both inspiration and expiration, apnea-hypopnea index was found to be significantly correlated with maximum velocity (P = .05) and airway resistance (P = .024, 0.038).

Conclusions: The edentulous patients with severe OSA have a more hourglass-shaped upper airway. The findings also suggest that, during inspiration, the airflow travels faster in edentulous patients with severe OSA than in those with mild or moderate OSA.

Clinical trial registration: Registry: ClinicalTrials.gov; Name: The Effect of Nocturnal Wear of Dentures on Sleep and Oral Health Related Quality of Life; URL: https://ichgcp.net/clinical-trials-registry/NCT01868295; Identifier: NCT01868295.

Citation: Chen H, Elham E, Li Y, et al. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med. 2022;18(3):759-768.

Keywords: apnea-hypopnea index; computational fluid dynamics; cone beam computed tomography; edentulism; obstructive sleep apnea; older adults; upper airway.

Conflict of interest statement

All authors have seen and approved this manuscript. Work for this study was performed at University of Montreal, Canada. This study was funded by the Canadian Institutes of Health Research (grant number 325899), Canadian Foundation of Innovation (CFI 28236), Shandong Provincial Natural Science Foundation (grant number N.ZR2020QH161), and by the China Oral Health Foundation (Grant number A2021-102). The authors report no conflicts of interest.

© 2022 American Academy of Sleep Medicine.

Figures

Figure 1. The 3-dimensional anatomic analysis of the upper airway.

(A) The midsagittal plane of the CBCT image (1 = PNS, posterior nasal spine; 2 = BEP, base of epiglottis). (B) The minimum cross-sectional area (Min-CSA) on an axial slice of the CBCT image. (C) The segmented upper airway. AP = anterior-posterior dimension of the Min-CSA, CBCT = cone beam computed tomography, Lateral = lateral dimension of the Min-CSA.

Figure 2. The aerodynamic analysis of the upper airway.

(A) The upper airway model used for CFD analysis. (B) Contours of wall static pressure (Pa), wall shear stress (Pa), and velocity (m/s) and static pressure (Pa) at the midsagittal plane of a typical edentulous patient with OSA during inspiration. (C) Contours of wall static pressure (Pa) and wall shear stress (Pa), and velocity (m/s) and static pressure (Pa) at THE midsagittal plane of a typical edentulous patient with OSA during expiration. CFD = computational fluid dynamics, OSA = obstructive sleep apnea.