Cochlear implantation in a child with severe cochlear hypoplasia

The child was identified as having bilateral profound hearing loss at the age of 2 years. He had bilateral hearing aids and continued aural habilitation until the age of 9 years 6 months, but his speech-perception skills didn’t improve. Preoperative pure-tone audiogram revealed hearing thresholds of 104 dB HL in his right ear and 110 dB HL in his left ear. Preoperative computed tomography (CT) and magnetic resonance imaging (MRI) with the three-dimensional volume-rendering image of the inner ear revealed bilateral severe cochlear hypoplasia with rudimentary cochlear bud (Figure 1). Promontory stimulation test (PST) revealed auditory perception bilaterally. Promontory stimulation electrical auditory brainstem response (PS-EABR) demonstrated auditory response to electrical stimulation with the right ear response better than the left. He underwent right-side cochlear implantation (Nucleus CI24R ST) at the age of 9 years 6 months. Cochleostomy was tried by drilling on the cochlear bud, but the cochlear lumen was not identified. Therefore 12 electrodes were inserted into the vestibule through the oval window niche after stapedectomy. No surgical complications occurred postoperatively. 210 Cochlear Implants International, 5(Supplement 1), 2004 ©Whurr Publishers Ltd