Microvascular decompression of the cochlear nerve in patients with severe tinnitus. Preoperative findings and operative outcome in 22 patients.

We evaluated the operative outcome in 22 consecutive patients who underwent microvascular decompression (MVD) of the intracranial portion of the cochlear nerve to relieve incapacitating tinnitus and related it to preoperative findings. The patients were selected for operation from the following criteria: severe tinnitus with sensorineural hearing loss and/or changes in brainstem auditory evoked potentials (BAEPs). Fifty percent had unilateral tinnitus. Before operation, 17 patients (77%) had sensorineural hearing loss in their affected ear. BAEPs were abnormal in 21 patients (95%) and acoustic middle ear reflex response was abnormal in six patients (27%). Vascular compression of the cochlear nerve was found in all patients during the operation. After the operation, 33% had relief of their tinnitus (two patients were totally free of tinnitus and five were markedly improved). Eight patients were slightly improved (38%), and the tinnitus did not change in four patients; two patients (10%) became worse. Of the patients with unilateral tinnitus, 63% had relief of their tinnitus. In one patient hearing was noticeably improved after the operation. Five patients (23%) had mild to moderate sensorineural hearing loss due to the operation. No other complications were detected.