Hearing loss after microvascular decompression for trigeminal neuralgia.

Of 21 patients examined audiometrically before and after microvascular decompression of the trigeminal nerve, five (23.8%) had postoperative hearing impairment. A middle ear effusion was found in three (14.3%), probably caused by mastoid cell opening. A retrocochlear lesion in the other patients was caused by transferred pressure on the cochlear nuclei or by traction on the nerve. Vascular perfusion problems were also possible but are difficult to document.