Endoscopic Repair of Round Window Cochleocele

Abstract

Objective: To describe the novel presentation, implications, and endoscopic management of a congenital round window cochleocele. Patient: A 16-month old girl with profound hearing loss from bilateral incomplete partition type 1 (IP1) anomaly of the cochlea plus left-sided cochlear nerve aplasia and cochleocele. Intervention: Anomalies were identified with computed tomographic scanning and magnetic resonance imaging during cochlear implant candidacy assessment. While under general anesthesia for right-sided cochlear implantation, the cochleocele was removed and packed with temporalis fascia using transcanal endoscopic ear surgery. The endoscope was held by an assistant while the surgeon packed the round window using a two-handed technique to counter the gush of cerebrospinal fluid. Results: The child made an uneventful recovery with no cerebrospinal fluid leak or meningitis.Conclusions: Cochleocele can protrude through the round window of a cochlea with incomplete partition type 1 anomaly. An increased risk of meningitis secondary to acute otitis media is expected given the known risk from cochleocele arising through a stapes footplate fistula. Care should be taken to check for the presence of a cochleocele in hearing loss from congenital malformations involving the basal turn of the cochlea on imaging and also at the time of cochlear implant surgery. Repair should be considered at the first opportunity to prevent meningitis. If early cochlear implant surgery is not feasible or appropriate (as, for example, with cochlear nerve aplasia), transcanal endoscopic ear surgery provides good access for a low-morbidity approach.