Early Outcomes with a Slim, Modiolar Cochlear Implant Electrode Array

OBJECTIVE: To describe outcomes from cochlear implantation with a new, slim modiolar electrode array. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral centers. PATIENTS: Adult cochlear implant candidates. INTERVENTIONS: Cochlear implantation with CI532 (Cochlear Corp). MAIN OUTCOME MEASURES: Pre- and postoperative speech perception scores, operative details, and postoperative computed tomography (CT) reconstructions of array location. RESULTS: One hundred seventeen patients are implanted to date. There were eight tip rollovers identified with intraoperative x-ray and resolved with reinsertion. An additional rollover was identified on postoperative CT. CT reconstructions in 17 of 23 patients showed complete scala tympani placement with a wrap factor of 58% (range 53-64%) and a mean insertion angle of 406 degrees (range 360-452 degrees). Three implants demonstrated array translocation with electrodes in the scala vestibuli. Consonant-nucleus-consonant word scores improved from 10% preoperatively to 48% at 3 months postoperatively. Pure-tone thresholds were preserved postoperatively in 37 to 52% of patients across frequencies from 250 to 4000 Hz. Functional pure-tone thresholds (≤80 dB) were recorded in 9 to 25% of patients. CONCLUSION: CI532 array insertion results in consistent scala tympani location and provides expected audiologic performance. Initial hearing preservation results are not consistent with current electro-acoustic arrays.