Outpatient NOHL vs. sleep endoscopy NOHL classification: analysis on score and pattern correlations of oro and...

Obstructive Sleep Apnea (OSA) is a prevalent disorder managed with CPAP, though adherence is often poor. Alternatives include MAD, positional therapy, and surgery. Drug-Induced Sleep Endoscopy (DISE) allows dynamic airway assessment. This study compares NOHL classification in awake versus sedated states to evaluate differences in collapse patterns and severity.

This study enrolled adult OSA patients (confirmed by polysomnography) undergoing DISE between October 2023 and December 2024. Excluding comorbidities or incomplete data, patients were assessed using the NOHL classification during both awake and sedated states. Collapse degree and pattern at oropharyngeal and hypopharyngeal levels were compared to evaluate concordance.

We enrolled 96 OSA patients (93.8% male; mean age: 52 years). A comparison between evaluations performed during wakefulness using the Müller maneuver and those performed with DISE revealed significant discrepancies in the grades and patterns of oropharyngeal and hypopharyngeal collapse. DISE identified more severe collapses (> 2) and frequent changes in collapse patterns, particularly in latero-lateral collapses. Correlation between awake and sedated findings was low, but improved when categorizing collapse as above or below 50%. Circular patterns were notably unstable across both levels.

Our study confirms significant differences in collapse degree and pattern between awake and sedated assessments using the NOHL classification. These discrepancies influence surgical decision-making in OSA patients. Further research is needed to improve patient phenotyping and guide more accurate, personalized treatment strategies for optimal surgical outcomes.