Rupture of the round window membrane.

The mechanism of development of rupture of the round window membrane appears to be an increase in pressure in the cerebrospinal fluid transmitted to the inner ear via the cochlear aqueduct. Two cases of rupture of the round window membrane in divers are described in detail. One diver had ruptures of both round window membranes following difficulty in autoinflating when diving, and the other had a rupture of one round window membrane, having presented with acute prostating vertigo and normal hearing. Surgical repair restored the hearing in the former case and preserved normal hearing in the latter. The similarity between ruptures of the round window membrane and poststapedectomy fistula is emphasized, and it is suggested that spontaneous healing of ruptures may well occur. A case history supporting this hypothesis is presented. The technique of repair of ruptures of the round window membrane is described as well as postoperative management. Normal nasal function in divers is essential if inner ear barotrauma and ruptures of the round window membranes are to be avoided.