Cochlear hair cell loss in ears with cholesteatomas. Scanning electron microscopy study

Cochleas from 16 Mongolian gerbils with spontaneous aural cholesteatomas, and four of similar age without cholesteatomas, were examined by scanning electron microscopy to quantify cochlear hair cell loss. Loss of hair cell stereocilia was found in all ears with cholesteatomas and was significantly increased when compared with uninvolved ears from animals of similar age. The hair cell loss associated with gerbilline cholesteatomas appeared to be most marked in the middle turn of the cochlea and increased in severity with increasing size of the cholesteatomas. Outer hair cells were affected more than inner hair cells. Inner and outer hair cell loss was not significantly different in infected cholesteatomas versus sterile cholesteatomas. The greater damage to hair cells at the middle turn compared to the basal turn suggests that these losses may be the result of some agent acting through the cochlear wall rather than through the round window.