Cholesteatoma with extension to the cochlea.

Cholesteatoma invading the membranous labyrinth has been regarded as a serious threat to inner ear function. Thus, a so-called dead ear might be created either by labyrinthine invasion of the cholesteatoma itself or by surgical intervention. A number of reports, however, have contradicted these "established facts," citing patients who have had some degree of hearing in the affected ear before as well as after surgical removal of the cholesteatoma. In the majority of these cases, however, only the vestibular labyrinth was involved, leaving the cochlea unaffected. In the few case reports describing actual invasion of the cochlea, hearing was lost in the affected ear either as a direct consequence of the operation or after an interval of some months. These findings might indicate that the two parts of the inner ear, to some degree, may be functionally separate so that cochlear function could be retained in spite of partial vestibular ablation. We report three cases of intracochlear cholesteatoma. All affected ears had some degree of auditory function before surgical treatment. All three patients presented with partial or total facial nerve palsy on the affected side. After surgery none of the patients had any hearing in the operated ear. The pathophysiologic significance of a functioning cochlea that has been proved to be invaded by cholesteatoma will be discussed. The criteria for correct preoperative management as well as for choice of treatment will also be discussed.