LwPTL: a Novel Classification for Upper Airway Collapse in Sleep Endoscopies

Introduction: There is no consensus on a single classification system for the obstructive findings in drug-induced sleep endoscopy. Previous classification systems have neglected to address the upper retropalatal obstruction, the segmental division of the lateral pharyngeal wall and the primary or secondary nature of laryngeal collapse.

Objective: To propose, illustrate and evaluate a more comprehensive and yet simple classification for drug-induced sleep endoscopy findings.

Methods: Cross sectional study in a tertiary sleep surgery unit. A total of 30 patients with obstructive sleep apnea underwent drug-induced sleep endoscopy according to a new classification system called LwPTL, and its findings were analyzed according to obstructive sleep apnea severity and body mass index. LwPTL incorporates the description of upper retropalatal collapse, distinguishes the lateral pharyngeal wall collapse into three levels and clarify when laryngeal collapses are primary or secondary.

Results: 93.3% of the patients presented lateral pharyngeal wall collapse, usually at the level of the velum (73.3%). 80% presented multilevel collapse. Regarding the upper retropalatal region, LwPTL identified 10% of the cases presenting lateral salpingopharyngeal obstruction and 6.6% with high palatal collapse. 3.3% presented epiglottic collapse. Patients presenting lower levels of collapse, either from the lateral wall and/or tongue and/or larynx, represented 30% of the cases and had significantly more severe obstructive sleep apnea, without significant differences in body mass indexes.

Conclusion: LwPTL seems a simple and straightforward staging system for classifying drug-induced sleep endoscopy, distinguishing the important upper retopalatal obstruction and the primary and secondary laryngeal collapses, providing more information for appropriate treatment selection.