LAUSR

Mandibular advancement device (MAD) is designed to pull the mandible and the tongue forward anteriorly to increase the cross-sectional airway dimension and thus possibly reduce airway obstructions during sleep. The effectiveness of a MAD may be affected by the pre-treatment OSA severity, BMI, and degree of changes in pharyngeal dimensions resulting from the device in situ. In this study, 3D submental ultrasound imaging is applied to evaluate the difference in the tongue and airway configurations between the responders and non-responders of the MAD treatment. In this retrospective study, 31 subjects (25 males, median age/BMI/baseline AHI of 56/24.5/25.3) diagnosed with sleep apnea and underwent tongue-backing-MAD (t-MAD) treatment were consented from the Department of dentistry of National Taiwan University Hospital between April and December 2022 (IRB 202108078RIPD). Changes in the severity of OSA were assessed with polysomnographic studies. Success of t-MAD treatment was defined by an AHI of less than 10 events/hour and at least 50% decrease in AHI from baseline. There were no significant differences in age, BMI, gender and baseline AHI between responders (17) and non-responders (14). While awake and lying in supine position, the tongue and airway configurations at retropalatal and retroglossal regions without and with t-MAD in situ were assessed with standardized 3D submental ultrasound imaging (AmCAD BioMed Corp., Taiwan). Statistical comparisons were performed using t-tests, chi-square tests and nonparametric Mann-Whitney tests. The anteroposterior location of the tongue-airway interface at retroglossal region, relative to the superior-inferior location of the soft-palate-airway interface, was found significantly reduced in responders when t-MAD is in situ (p = 0.0078). 13 responders (76.5%) and 9 non-responders (64.3%) were observed with airway width increase in the retroglossal region with t-MAD in situ. However, the difference in airway width changes between responders and non-responders was not statistically significant possibly due to the limited sample size. With the real-time visualization and quantitative characterization of the tongue and airway configurations, the 3D submental ultrasound with standardized imaging protocol is able to differentiate the responders from non-responders of the t-MAD treatment and could be a potential tool for treatment response evaluation.