か牛ろう孔を来した中耳真珠腫の３症例

Abstract

Labyrinthine fistulas found during surgery for treatment of chronic otitis media with cholesteatoma, most commonly involve the horizontal semicircular canal. The overall incidence of cochlear fistula, however, is low. In the present study, we report three cases of cholesteatoma with a labyrinthine fistula in the cochlea. No additional fistulas were found in the semicircular canals or vestibule, and the inside of the cochlea was found to be completely dry in all three cases. Case 1 (56y male) had profound sensorineural hearing loss, and case 2 (56y male) and case 3 (20y male) were totally deaf before the surgery. All of them had suffered from persistent and active inflammation for a long period of time. Middle ear computed tomography (CT) could identify the presence of the cochlear fistula. The pathway from the epitympanum to the additus & antrum of the mastoid was found be very narrow in cases 1 and 2 during the surgery. Therefore, large pressure, due to the cholesteatoma may be present at the mesotympanum, and could not be released to the mastoid, potentially causing the development of a large cochlear fistula. In case 3, because middle ear pneumatization was good, and the cholesteatoma was present in a very restricted area on the anterosuperior part of the promontry, a congenital origin arisig from epideromoid formation was suspected.We also reviewed the 12 additional cases of cochlear fistulas reported since 1974. As suggested previously, the hearing prognosis is very poor in most cases of cochlear fistulas.