OBJECTIVES/HYPOTHESIS: With low-dose and titration protocols, subsequent intratympanic (IT) gentamicin injections are frequently necessary for vertigo control in M'eni`eretextquoterights disease. To date, studies have not provided detailed descriptions of the time course of recurrent vertigo and repeated injections. Our objective is to provide such a description with a Kaplan-Meier survival analysis, which may enable accurate predictions of the probability of recurrent vertigo after a given time or number of injections.
STUDY DESIGN: Injections of IT gentamicin were administered for unilateral definite M'eni`eretextquoterights disease. One injection (or rarely more) in a 6-week period constituted a "round." Repeat rounds were given when needed for control of recurrent vertigo.
METHODS: We used a Kaplan-Meier method to quantify percentages of patients with control of vertigo over an 8-year period. A separate curve was created for each number of rounds, and failure for each was defined as the need for an additional round.
RESULTS: Of 78 patients, 75 (96%) achieved sufficient vertigo control to avoid ablative surgery, and 42 (54%) required only one round. Thirty-six (46%) required multiple rounds. The probability of needing another round increased with each subsequent one, through four rounds. The median times to the next round after one, two, or three rounds were 148, 118, and 124 days, respectively.
CONCLUSIONS: More than half of patients need only one round of IT gentamicin injections. With each additional round through the fourth one, the probability of additional rounds increases. Nevertheless, the majority (96%) of patients do not need ablative surgery after IT gentamicin.