[Further development of pneumatization of the mastoid apophysis in long-term drainage of the tympanum].

Tubal insufficiency evoked by inflammation or mechanical obstruction due to enlarged adenoids plays an important role in the pathogenesis of chronic serous otitis media. Serous and mucous tympanic effusions in the presence of immature middle ear mucosa and pneumatisation follow. An adhesive process can be the result. Secretory outflow as well as constant pressure compensation between the tympanic cavity and the auditory meatus can only be achieved by a long-term tympanic drainage. Progression of pneumatisation is achieved by recovery of the middle ear mucosa and in most cases an adhesive process can be prevented.