The pathogenesis of maxillary sinus pneumoceles.

Pneumocele is a pathologically expanding, air-containing paranasal sinus most common in the frontal sinus. To our knowledge, only six cases of pneumoceles of the maxillary sinus have been reported so far; to these we add a seventh. The pathogenesis of pneumoceles has not been fully understood. It has been postulated that a one-way valve between the nasal cavity and the affected sinus leads to increased antral pressure and sinus expansion after nose blowing. By monitoring antral pressure through a transoral puncture, we demonstrated a one-way valve between the nose and the maxillary antrum. To our knowledge, this is the first verification of the trap-valve hypothesis.