Time-dependent changes in the obstruction pattern during drug-induced sleep endoscopy

PurposeDrug-induced sleep endoscopy (DISE) is used to identify the site of obstruction causing obstructive sleep apnea (OSA). However, previous studies have reported a wide range of DISE findings, and new patterns of airway obstruction have also been observed during postoperative DISE. Therefore, we aimed to determine the features of changes in obstructive patterns during DISE.Materials and MethodsForty-two patients diagnosed with OSA underwent DISE for 25 min. Sites of obstruction were determined at the levels of the velum, lateral wall of the oropharynx, tongue base, and epiglottis. The velum obstruction configuration was classified as anteroposterior, lateral, or concentric.ResultsThe obstructive pattern changed in 14 patients (33%). We observed a change in the site of obstruction in 9 patients (21.4%) and in the configuration of velum obstruction in 5 patients (11.9%). The changes occurred between 3 and 22 min after commencing DISE (mean, 10.6 ± 6.2 min). The proportion of obstructions in the velum, lateral wall of the oropharynx, and tongue base increased with longer DISE durations. The proportion of multiple-level obstructions increased significantly after 15 min (P < 0.05). In the velum, anteroposterior obstructions in 2 patients and lateral obstructions in 3 patients changed into concentric obstructions. More configurations were observed with longer procedure durations.ConclusionsHence, we assume that it is possible to miss the site of obstruction during DISE if the procedure is too short, which may partly explain the discrepancies between studies.