OBJECTIVE: To determine the long-term hearing outcome in patients with intractable vertigo caused by unilateral M'eni`eretextquoterights disease who were treated with intratympanic injection of gentamicin.
STUDY DESIGN: The study was a longitudinal analysis of hearing and control of vertigo in patients with unilateral M'eni`eretextquoterights disease who received intratympanic gentamicin.
METHODS: Pure-tone thresholds and speech discrimination scores on audiometry were analyzed, along with the control of vertigo. Criteria described in 1995 by the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) were used. Patients treated with intratympanic gentamicin had "definite" M'eni`eretextquoterights disease and had intractable vertigo despite optimal medical therapy, no symptoms suggestive of M'eni`eretextquoterights disease in the contralateral ear, and serviceable hearing in the contralateral ear. The study analyzed the outcomes of 34 patients for whom follow-up data were available for periods greater than 24 months after intratympanic gentamicin.
RESULTS: Complete control of vertigo (AAOHNS Class A) was obtained in 90% of the patients. Profound sensorineural hearing loss occurred as a result of gentamicin injection in 1 of the 34 patients (3%). When data from all patients were grouped together, hearing was improved in 5 (15%), unchanged in 23 (68%), and worse in 6 (17%) patients. This distribution of hearing outcome is similar to that in patients whose symptoms of M'eni`eretextquoterights disease were managed with medical measures. Recurrent vertigo developed in 10 patients (29%) at an interval of 4 to 15 months after initially complete control. Treatment with additional intratympanic injection(s) of gentamicin did not result in a change in hearing.
CONCLUSION: The risk of hearing loss in patients treated with infrequent intratympanic injection(s) of gentamicin is low.