The round window in acute hearing loss.

Sensorineural hearing loss has various etiologies. One of them is perilymphatic fistula, which is observed in (1) congenital malformation of the internal ear in children: (2) after operations on the oval window (stapedectomy, interposition); (3) in cases of head trauma, and (4) in acute hearing loss of unknown origin. The authors report 5 of 19 cases of acute hearing loss observed at the ORL Clinic in Kraków and operated on by exploratory tympanotomy. In 4 of them, rupture of the round window membrane (secondary tympanic membrane) was found. A hypothesis for the rupture mechanism is presented.