Microvascular decompression of the eighth nerve in patients with disabling positional vertigo: selection criteria and operative results in 207 patients.

Two-hundred seven patients who were operated on consecutively between January 1983 and December 1990 to relieve disabling positional vertigo (DPV) using the microvascular decompression (MVD) procedure were studied. Selection of the patients for MVD operations was based on both case history and the results of otoneurological tests. Of the 177 patients with unilateral symptoms, 8 were excluded because of previous vestibular nerve section, and 6 did not return for follow-up; of the remaining 163 patients, 129 (79%) were free of symptoms or markedly improved following MVD, and none became worse. Thirty patients had symptoms and signs of bilateral DPV, and of these 1 was excluded because of previous vestibular nerve section and 3 because of multiple operations. Of the remaining 26 patients, 20 (77%) were free of symptoms or markedly improved following MVD. Eleven of these patients had more than 2 operations. The follow-up time was an average of 38 months, ranging from 3 months to 10 years. The cure rate (about 80%) of MVD for DPV is similar to that reported for MVD for trigeminal neuralgia and hemifacial spasm. The cure rate of MVD for DPV was not related to gender or to the duration of the symptoms. Following a total of 254 operations that these 207 patients underwent, 4 patients (1.6%) lost hearing and 4 (1.6%) suffered marked hearing loss. Three patients suffered temporary deficits of other cranial nerves. There were no other complications to these operations.