Localization, frequency, and severity of endolymphatic hydrops and the pathology of the labyrinthine membrane in Menière's disease.

The localization, frequency, and severity of endolymphatic hydrops in 22 temporal bones of 16 individuals with Meniere's disease were studied histopathologically. Endolymphatic hydrops was more often observed in the pars inferior (22/22) than in the pars superior (13/22) of the temporal bone, and severe hydrops was observed most frequently in the saccule, followed by the cochlea, the utricle, and the three semicircular canals. In the cochlea, the most severe hydrops was observed in the apical turn, followed by the hook portion, the middle turn, and the basal turn. Clinically interesting observations regarding endolymphatic hydrops included bulging into the perilymphatic space of the vestibule. In 17 of 22 bones the saccular membrane bulged into the vestibule laterally and was attached to the footplate of the stapes. In two of 22 bones, Reissner's membrane in the hook portion of the basal turn of the cochlea bulged superiorly into the vestibule, occupying most of the perilymphatic space of the vestibule.