The nose oropharynx hypopharynx and larynx (NOHL) classification: a new system of diagnostic standardized examination for OSAHS patients.

The main pathological event of obstructive sleep apnea hypopnea syndrome (OSAHS) is the apneic collapse of the upper airways (UA). Frequently, UA collapse occurs at the same time at different section levels. Identifying the site and the dynamic pattern of obstruction is mandatory in therapeutical decision-making, and in particular if a surgical therapy option is taken into account.