Ungar OJ; O'Shea R; Hassannia F; Rutka JA · 2026 · The Laryngoscope
Paper
OBJECTIVE: To evaluate cochleovestibular outcomes following trans-mastoid superior semicircular canal (SSC) occlusion in patients with symptomatic superior semicircular canal dehiscence (SSCD) and third-window syndrome (TWS), and to characterize objective pre-and postoperative functional changes in a tertiary-center cohort. METHODS: Medical records of patients undergoing trans-mastoid SSC occlusion for SSCD with TWS were retrospectively reviewed. Diagnosis was based on characteristic cochleovestibular symptoms, physical examination, and imaging findings. Standardized pre- and postoperative assessments included pure-tone audiometry, videonystagmography (VNG), ocular vestibular evoked myogenic potentials (oVEMP), video head impulse testing (vHIT), and electrocochleography (EcochG). Surgery was performed through a postauricular trans-mastoid approach with SSC plugging using autogenous periosteum reinforced with temporalis fascia, bone pâté, and fibrin sealant. RESULTS: Twenty patients underwent surgery. Preoperative symptoms included hearing loss (95%), autophony (85%), and Tullio phenomenon (70%). Mean preoperative 500-Hz air-bone gap was 25 ± 8.7 dB. Affected ears demonstrated significantly reduced oVEMP thresholds (p < 0.001) and elevated EcochG SP/AP ratios compared with contralateral ears (0.212 ± 0.086 vs. 0.275 ± 0.071, p < 0.001). Following surgery, all patients reported symptomatic improvement with complete resolution of Tullio phenomenon. Mean air-bone gap improved to 4.3 ± 6.1 dB with preserved speech recognition. SP/AP ratios normalized postoperatively and were comparable between ears (p = 0.062). oVEMP thresholds normalized compared to contralateral ears. vHIT demonstrated reduced gain in the operated canal (0.49 ± 0.18 vs. 0.84 ± 0.05, p < 0.001), while caloric responses remained unchanged. CONCLUSIONS: Trans-mastoid SSC occlusion provides effective symptom relief with favorable cochleovestibular outcomes in SSCD with TWS. Objective testing demonstrates restoration of third-window physiology while preserving hearing and overall vestibular function.
Analysis
This study evaluates the effectiveness of trans-mastoid superior semicircular canal (SSC) occlusion in patients with symptomatic superior semicircular canal dehiscence (SSCD) and third-window syndrome (TWS), demonstrating significant symptom relief and restoration of normal cochleovestibular function.
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