Audiological outcomes of salvage intratympanic corticosteroid therapy in idiopathic sudden sensorineural hearing loss

INTRODUCTION: Intratympanic corticosteroids (ITCs) are used to treat patients with idiopathic sudden sensorineural hearing loss (ISSNHL) when systemic therapy has been unsuccessful. However, the efficacy of this treatment remains uncertain. METHODS: We retrospectively analysed ISSNHL patients at a tertiary reference center, who received ITC injections following unsuccessful systemic corticosteroid therapy administered either orally or intravenously. Patients were eligible for ITC if they showed insufficient improvement after systemic treatment, defined as a remaining hearing loss of ≥30 dB HL in at least three frequencies. They received three intratympanic injections of 0.3-0.5 mL dexamethasone (4 mg/mL) within 10-14 days from first to last injection. Changes in pure-tone audiometry were assessed. RESULTS: A total of 34 patients met the inclusion criteria for the study. The mean pure tone average (PTA) improvement was 10.62 dB HL. A total of 18 patients (53%) showed hearing improvement of ≥10 dB HL (of these: n=11 (32%) ≥20 dB HL, n=2 (6%) ≥30 dB HL). Sixteen patients (47%) had an improvement of less than 10 dB HL. In addition to the PTA analysis, individual frequencies at 0.5 kHz, 1 kHz, 2 kHz, and 4 kHz were examined and showed significant improvements, with p-values ranging from 0.007 to 0.037. Regarding the World Health Organization grading of hearing impairment, 13 patients (38.2%) improved by at least one category. Concomitant vestibular syndrome (n=5) showed a marginally non-significant trend (p = 0.066) towards less improvement. There was no significant correlation between age and degree of hearing loss (p = 0.123). Complications of ITC were minimal, with only one patient reporting a temporary headache following injection. CONCLUSION: In patients with persistent ISSNHL after systemic corticosteroid therapy, intratympanic corticosteroid injections resulted in limited hearing improvement. Despite the low risks associated with this therapy, its routine use should be considered on a case-by-case evaluation.