Diagnosis of upper airways collapse in moderate-to-severe OSAHS patients: a comparison between drug-induced sleep endoscopy and the awake examination

Purpose Compare awake evaluation (modified Mallampati score-MMs, Muller maneuver-MM) to drug-induced sleep endoscopy (DISE) findings according to NOHL (nose-oropharynx-hypopharynx-larynx) classification in moderate-to-severe OSAHS patients. Methods 43 moderate-to-severe OSAHS patients referred to our ENT department were enrolled over a 2-year period. In this observational prospective study, each patient was evaluated by the same ENT team both in wakefulness and during pharmacologically induced sleep. Level and severity of the obstruction were described. Results The comparison of degree of collapsibility was statistically significative only at hypopharyngeal level: 41.8% of the patients showed a hypopharyngeal obstruction in wakefulness whereas 88.3% in DISE (p = 0.000). Laryngeal level was found in 18.6% patients during awake examination, conversely DISE demonstrated laryngeal obstruction in 4.6%. DISE identified significantly higher incidence of multilevel collapses (p = 0.001). However, the incidence of oropharyngeal obstruction in patients classified as MMs I and II was significantly higher in DISE compared to MM (p = 0.021). Conclusion DISE is the best predictor of hypopharyngeal obstruction, whereas MM underestimates the severity of the collapse at this level. DISE is more reliable than MM to identify the obstruction in patients with MMs score I and II.