Meta-Analysis of Obstruction Site Observed With Drug-Induced Sleep Endoscopy in Patients With Obstructive Sleep Apnea

Objective To perform a meta-analysis on the distribution and characteristics of the obstructive site in patients with obstructive sleep apnea (OSA) using data from a variety of published studies that evaluated the obstruction with drug-induced sleep endoscopy (DISE). Methods A literature search was performed to identify studies in which DISE was used to identify the obstruction site in adult patients with OSA, and the obstruction site was described in sufficient detail. Four items were evaluated in the meta-analysis: the obstruction site, closing direction of the soft palate, degree of closure, and percentage of single-level obstructions. Results A total of 2,950 patients from 19 studies were included. In the two-level classification system, the rate of obstruction was 91.6% for the soft palate and 58.0% for the tongue base. In the four-level classification system, the rate of obstruction was 84.1% for soft palate, 32.8% for the tonsil, 51.6% for the tongue base, and 34.3% for the epiglottis. The soft palate closed in the anteroposterior direction at a rate of 44.4% and in the concentric direction at a rate of 46.5%. The rate of a closure of 75% or more was 69.3% for the soft palate and 56.8% for the hypopharynx. The percentage of single-level obstructions was 42.5%. Conclusion The soft palate is obstructed in most patients with OSA, and the tongue base is obstructed in half of the patients. In addition, multilevel obstructions including the tonsil, lateral pharyngeal wall, or epiglottis are common; thus, these areas must be checked carefully.