Idiopathic endolymphatic hydrops and the vestibular aqueduct.

The vestibular aqueduct (VA) and endolymphatic sac were examined topographically in 29 human ears with idiopathic endolymphatic hydrops. When compared with 34 control ears, there was found to be a slight but statistically significant reduction in the width (P less than 0.005) and length (P less than 0.05) of the vestibular aqueduct. A small hypoplastic endolymphatic sac was found in three of the ears with hydrops but was also present in one control ear. It would appear that a marked reduction in sac size is not a consistent feature in ears with endolymphatic hydrops.