Apical lesions of the cochlea in idiopathic endolymphatic hydrops and other disorders: pathophysiological implications.

Apical lesions of the cochlea may be caused by direct trauma, impairment of blood supply, contamination of perilymphatic fluid and endolymphatic hydrops. It is proposed that endolymphatic hydrops causes apical lesions when endolymph or its components leak into the perilymphatic fluid and pass through the helicotrema to degrade the tissue fluid environment of the sensory and neural structures in this area.