Efficacy of endoscopic single-session corticosteroid delivery via round window membrane for severe to complete sudden deafness salvage: a prospective cohort study

BACKGROUND: Sudden sensorineural hearing loss (SSNHL) often necessitates salvage therapy when unresponsive to systemic corticosteroids. AIMS/OBJECTIVES: We introduce a novel endoscopic-assisted surgical approach for precise, single-session inner ear drug delivery via the round window membrane to treat refractory SSNHL. MATERIAL AND METHODS: Patients underwent surgery for local administration of methylprednisolone through the round window membrane. And audiometry, CT scans and the severity of tinnitus and dizziness were evaluated during the follow-up period. RESULTS: 56 patients with severe-to-complete SSNHL were recruited, and the overall efficacy reached 55.4%. Mean Pure-Tone Average (PTA) threshold improved from 91.61 ± 11.37 dB to 76.79 ± 19.52 dB after 3 months (p < 0.0001). Among which, patients with profound and complete hearing loss exhibited substantial recovery, with average PTA reduction of 18.13 ± 18.51 dB (p = 0.0001) and 13.87 ± 10.20 (p < 0.0001), separatively. Timely intervention was also critical, the 13-day cutoff derived from ROC analysis represents a critical therapeutic window for salvage. Tinnitus and vertigo symptoms significantly improved after treatment (p < 0.0001). No treatment-related adverse events were observed. CONCLUSIONS AND SIGNIFICANCE: This approach provides a new, promising paradigm for the salvage treatment of refractory severe-to-complete SSNHL.