Audiometric Outcomes of Topical IGF1 Treatment for Sudden Deafness Refractory to Systemic Steroids

Objective: To examine the effects of topically applied recombinant human insulin-like growth factor 1 (IGF1) via gelatin hydrogels on alterations in pure-tone audiometry (PTA) in patients with sudden sensorineural hearing loss (SSHL) refractory to systemic steroids. Study Design: Retrospective chart review. Setting: A single university hospital. Patients: Twenty-five patients with SSHL refractory to systemic steroids who received topical IGF1 treatment. Intervention: Single topical application of IGF1 to the round window niche using gelatin hydrogels. Main Outcome Measures: The primary outcome was alterations in PTA thresholds at frequencies of 0.25, 0.5, 1, 2, and 4 kHz after topical IGF1 application. Secondary outcomes included differences in final improvements in PTA thresholds among frequencies tested and cumulative numbers of patients showing 10- or 20-dB recovery in PTA during the observation period. Results: Topical IGF1 application via gelatin hydrogels significantly altered PTA thresholds at each frequency tested and at the average frequency. The numbers of patients with a 10-dB recovery in PTA increased until 4 weeks after treatment and then stabilized, whereas those patients showing 20-dB recovery gradually increased during the observation period. Conclusion: Topical IGF1 application via gelatin hydrogels contributes to the recovery of PTA levels in patients with SSHL refractory to systemic steroids. Major recovery of PTA levels occurs within 4 weeks after treatment.