[Otosclerosis--diagnosis and therapy].

Otosclerosis (synonym: otospongiosis) is a focal or diffuse spongifying disease of the bony labyrinth. So far pathogenesis is unknown, some recent investigations assume a paramyxovirus infection. But there are no doubts about hereditary and genetic factors, females are twice often affected as males with a maximum incidence between 20 and 40 years. If the disease invades the oval window niche it causes fixation of the stapes with conducting hearing loss. In some cases otospongiosis is associated with and presumably causes cochlear degeneration alone with sensoneurale hearing impairment of varying degree. The surgical technique is now well developed and the operative treatment enables in over 90% a closure of the air-bone gap by using stapes pistons. The medical therapy in cases of sensoneural hearing loss with sodium fluoride is still controversially discussed.