In 1971, one of the authors reported sudden deafness associated with labyrinthine window membrane ruptures. Eighteen additional cases have been explored surgically since then. Data on 21 cases are presented. Sudden profound cochlear deafness has now been encountered in 21 cases which were surgically explored. In 15 instances, fistulae of round, oval, or both windows were encountered and repaired. In 10 of the 15, there was a definite history of sudden exertion or trauma prior to onset. The oval window alone was ruptured in nine patients, the round window alone in one, and both windows were ruptured in five patients. The oldest patient was 62 years and the youngest 11 years of age. Differential audiological studies showed profound losses in all cases. Almost every case was studied by pure tone AC-BC and speech audiometry, Békésy, and impedance tests. Whenever possible other audiologic tests, such as recruitment, tone decay, and SISI were performed. These findings are presented in detail. Vestibular function was studied by electronystagmography (ENG) in 15 of the 21 cases surgically explored. There was evidence of vestibular dysfunction in almost every case with sudden hearing loss. Significant ENG details are presented. Surgical repairs of ruptured window membranes were followed by improvements in some of the patients. Postoperative audiologic data are presented. The theoretical aspects include discussion of possible cerebrospinal fluid (CSF) perilymph pathways between cochlear aqueduct and scala tympani and between internal auditory meatus and scala vestibuli. It is concluded that spontaneous labyrinthine window ruptures must now be added to the etiologic factors in “sudden hearing loss.” It is premature to set down criteria for surgical intervention in such cases. Further careful studies are necessary.
A HISTOLOGICAL STUDY OF COCHLEAR AQUEDUCT
