Spontaneous perilymphatic fistula: electrophysiologic findings in animals and man

The case against the occurrence of spontaneous perilymphatic fistulas is presented. Electrophysiologic findings both in animals and in man suggest that small holes in either the round or oval window are not associated with any significant hearing loss. Removal of perilymph may cause some changes in the electrocochleogram that can be reversed when the perilymph is replaced. Tympanotomy surgery, especially when performed with the injection of local anesthetic solutions may result in transudates in the middle ear that are difficult to differentiate from perilymph leaking out from the inner ear. Perilymphatic fistulas were excluded by performing a posterior myringotomy under general anesthesia in 162 congenitally deaf ears. If fluid was present it was suctioned, and if no change occurred on the intraoperative electrocochleogram, it was concluded that no fistula existed. Based on the electrophysiologic findings and the clinical observations in over 240 ears, it was concluded that spontaneous perilymphatic fistulas do not exist. The author accepts that perilymphatic fistulas occur after surgery, especially after stapedectomy, and that they can occur after head injury or barotrauma. However, these should heal readily; persistent or intermittent fistulas are an otologic rarity.