Round Window Drill-Out in Advanced Otosclerosis

OBJECTIVE: To discuss the effect of round window drill-out for otosclerosis cases with radiographic evidence of round window obliteration. PATIENTS: Four adult patients (5 ears) were included with audiometric findings of a mixed hearing loss and radiographic evidence of otosclerosis causing round window obliteration. INTERVENTIONS: Round window obliterative disease was addressed with a formal round window drill-out (RWD) by opening the lumen of the basal turn of the cochlea with a micro drill. The opening was then reconstructed with fascia to recreate a 2-window system. MAIN OUTCOME MEASURES: Feasibility, Δ pure-tone air conduction thresholds, and Δ pure-tone average air-bone gap (PTA-ABG). RESULTS: Three (60%) ears underwent primary or revision stapedectomy with RWD, 1 (20%) ear underwent delayed RWD years after stapedectomy, and 1 (20%) ear underwent RWD without stapedectomy. Median preoperative PTA-ABG was 31.3 dB. One patient (2 ears) had significant benefit with PTA-ABG improvements of 45 dB (left) and 30 dB (right). Two patients (2 ears) had a small improvement in PTA-ABG (2.5 dB, 1.3 dB), whereas 1 patient (1 ear) had worsening in PTA-ABG (2.5 dB). CONCLUSIONS: Patients suffering from severe mixed hearing loss due to advanced otosclerosis may benefit from formal RWD to facilitate hearing aid use as an alternative to cochlear implantation.