Dynamic Drug-Induced Sleep Computed Tomography in Adults With Obstructive Sleep Apnea

Abstract

Surgical success for obstructive sleep apnea (OSA) depends on identifying sites of obstruction in the upper airway. In this study, we investigated sites of obstruction by evaluating dynamic changes in the upper airway using drug-induced sleep computed tomography (DI-SCT) in patients with OSA. Thirty-five adult patients with OSA were prospectively enrolled. Sleep was induced with propofol under light sedation (bispectral index 70–75), and low-dose 320-detector row CT was performed for 10 seconds over a span of 2–3 respiratory cycles with supporting a continuous positive airway pressure model. Most (89%) of the patients had multi-level obstructions. Total obstruction most commonly occurred in the velum (86%), followed by the tongue (57%), oropharyngeal lateral wall (49%), and epiglottis (26%). There were two types of anterior-posterior obstruction of the soft palate, uvular (94%) and velar (6%), and three types of tongue obstruction, upper (30%), lower (37%), and upper plus lower obstruction (33%). DI-SCT is a fast and safe tool to identify simulated sleep airway obstruction in patients with OSA. It provides data on dynamic airway movement in the sagittal view which can be used to differentiate palate and tongue obstructions, and this can be helpful when planning surgery for patients with OSA.

Airflow Shape Is Associated With the Pharyngeal Structure Causing OSA

“…Previous studies performed during sleep using endoscopy, CT scan, and MRI have shown that the pharynx can obstruct at more than one site. 3,[22][23][24] Vroegop et al 22 performed drug-induced sleep endoscopy in 1,249 patients and showed that 68% had multilevel collapse. The most frequent combination was collapse of the palate and tongue base (26% of patients), followed by the palate and epiglottis (21% of patients).…”

“…Simultaneous airflow has not been used in previous studies. 3,[22][23][24] Third, we used a small amount of CPAP in patients with cyclic obstructive apneas to increase endexpiratory pharyngeal dimensions and facilitate the distinction between the pharyngeal structures. CPAP was also used for similar reasons by Li et al 24 in a study using dynamic upper airway CT scan to determine the site of pharyngeal collapse during sleep.…”

Intrapharyngeal surgery with integrated treatment for obstructive sleep apnea

“…Epiglottis collapse is commonly ignored at its role in contributing to OSA. In our previous study, epiglottis collapse existed in 25% of moderate to severe OSA patients [46] . Epiglottis collapse jeopardizes the use of CPAP and causes UPPP failure [16] , [17] .…”

“…The cause can be attributable to inappropriate mode or incorrect position. In our previous study of drug-induced sleep computed tomography scan in recognizing the levels of obstruction, we found that tongue collapse can be identified as upper (body, 30%), lower (base, 37%), and upper followed by lower (biphasic, 33%) collapse models from dynamic change in sagittal view [46] . Upper and biphasic models comprise 63% in our study population with tongue collapse, which are likely to be misdiagnosed as A-P collapse of the soft palate in drug-induced sleep endoscopy [47] .…”

Suspension Palatoplasty for Obstructive Sleep Apnea- A Preliminary Study

“…This suboptimal outcome may be attributable to primary tongue collapse that compresses the soft palate and presents as A-P palatal obstruction. In our previous study of drug-induced sleep computed tomography scan, tongue obstruction can be identified as upper (body, 30%), lower (base, 37%), and upper followed by lower (biphasic, 33%) obstruction models 18 . Upper and biphasic tongue obstruction comprise 63% in whole tongue obstruction, which are likely to be misdiagnosed as A-P palatal obstruction in endoscopic examination.…”