Secretory otitis media in adults: II. The role of mastoid pneumatization as a prognostic factor.

The sequelae of secretory otitis media (SOM) were monitored in 72 adult patients with SOM who were followed up for an average of 33 months. It was found that SOM became chronic and retraction of the tympanic membrane appeared as a function of the pneumatization of the mastoid. Ears with poor pneumatization (less than 6 cm2) developed chronic SOM in 52.2% of cases, as compared with 20% in cases with well-pneumatized ears (6 cm2 and above). Atelectasis developed in 37.3% of poorly pneumatized ears, and in only 5.7% of well-pneumatized ears. These sequelae may therefore be linked pathogenetically to the extent of pneumatization, as both the SOM and the sequelae appeared many years after formation and maturation of the pneumatic system. This study supports other studies that view the mastoid pneumatic system as an organ, as a middle ear pressure buffer. Well-pneumatized ears rarely develop a negative pressure and are seldom associated with chronic sequelae. Ears with poorly pneumatized mastoids lack the physiological function of such a pressure buffer. Ears with a tendency to develop a negative gas balance, whether as a result of deficient ventilation or excessive diffusion, will therefore develop a negative pressure more readily when their pneumatic system is underdeveloped, and consequently will be more prone to develop chronic sequelae.