Saccule otoconia displacement into cochlea in cochleosaccular degeneration.

Eight human temporal bones from five patients demonstrated varying degrees of cochleosaccular degeneration. Otoconial debris, with tissue reaction, was demonstrated within the ductus reuniens and cochlear duct, as far distal as the middle of the ascending basal limb. Saccule degeneration could be the primary lesion in cochleosaccular degeneration related to heredity or aging, with cochlear changes secondary to the presence of displaced otoconia. In cochleosaccular degeneration of viral cause, if saccule otoconial displacement occurs, it may possibly produce additional damage in a cochlea involved by viral infection. Cochlear damage might be related to the severity of otoconial displacement and/or to impaired clearing mechanisms of the cochlea. Retrograde cochlear hydrops, secondary to collapse of the saccule, occurs first in the cecum vestibulare and may extend distally.