Preservation of cochlear function after labyrinthine destruction — A report of 8 cases.

Abstract

It is well known that labyrinthine destruction by cholesteatoma or chronic otitis media results in cochlear dysfunction and makes bone conduction worse. However, we have infrequently encountered cases which maintained good bone conduction despite of labyrinthine destruction or improved the hearing after surgical removal of pathological lesion. In this paper such 9 ears of 8 cases are reported. Regarding protective mechanism in the endolymphatic space, Schuknecht et al speculated that the utriculoendolymphatic valve serves to protect the pars inferior from the disease of the pars superior. The disease is, however, considered to usually initiate in the perilymphatic space of semicircular canal after destruction of its bony wall and to spread through perilymphatic space to the cochlea. Protective mechanism in the perilymphatic route can not be explained only by the utriculoendolymphatic valve theory. The present authors postulate on the anatomical basis that a loose connective tissue in the perilymphatic space of the pars superior and membrana limitans may play a defensive role against the spread of inflammation from the perilymphatic space of the pars superior into the pars inferior. © 1980, The Oto-Rhino-Laryngological Society of Japan, Inc. All rights reserved.