Hybrid Cochlear Implantation With Increased Cochlear Insertion Depth

Sunday, October 1, 2023

1:42 PM - 1:48 PM East Coast USA Time

Location: 104BC

Presenting Author(s)

Douglas Josiah Totten, MD, MBA

Resident Physician
Indiana University School of Medicine, Department of Otolaryngology -- Head and Neck Surgery
Indianapolis, Indiana, United States

Co-Author(s)

KL

Karen Libich, AuD

United States
Evan C. Cumpston, MD

Neurotology Fellow
Indiana University School of Medicine , Department of Otolaryngology -- Head and Neck Surgery
Indianapolis, IN, United States
AS

Abdul Saltagi, BS

Medical Student
Indiana University School of Medicine, United States
dp

david pisoni, PhD

Indiana University School of Medicine, USA

Presenting Author(s)

Rick F. Nelson, MD, PhD

Professor
Indiana University
Zionsville, Indiana, United States

Disclosure(s):

Douglas Josiah Totten, MD, MBA: No relevant relationships to disclose.

Rick F. Nelson, MD, PhD: No relevant relationships to disclose.

Introduction: The relationship between increasing cochlear implant (CI) electrode array length and worse hearing preservation outcomes has been reported. The traditional hybrid CI electrodes are shorter (16 mm) than the full-length electrodes (25 mm). Combining increasing cochlear electrode insertion depth and low frequency hearing preservation may improve hybrid CI performance. We assessed the hearing preservation rates of the Cochlear Slim 20 electrode (20 mm) in patients with functional low frequency hearing.

Methods: Patients that met hybrid CI criteria and had unaided audiometric 1 kHz threshold >75 dB who underwent CI with Cochlear™ Nucleus® CI624 Slim 20 electrode between January 2021 and May 2022 were included. Pre-operative and post-operative acoustic low frequency thresholds and pure-tone averages (LFPTA, defined as the mean of audiometric thresholds at 250, 500, and 1000 Hz) were assessed. Preservation of low frequency hearing was defined as thresholds > 85 dB. Single-predictor linear regression was used to assess the impact of age, duration of hearing loss and pre- and postoperative hearing outcomes.

Results: 16 patients (18 ears) were implanted at an average (standard deviation) age of 68 (15) years and 81.3% of patients were male. Average duration of hearing loss was 31 (20) years. Hearing was preserved postoperatively in 16 of 17 (94%) ears with postoperative audiometry at 250 Hz, 13 (76%) at 500 Hz and 10 (59%) at 1K Hz postoperatively. Mean LFPTA increased 25 (22) dB to 63 (23) dB after implantation. Single predictor linear regression found no significant association between postoperative LFPTA and age or duration of hearing loss (P>0.05). Consonant-nucleus-consonant (CNC) score improved from 29.8% (standard deviation [SD]: 14.0%) to 55.8% (20.8%) postoperatively in best aided condition 6 months postoperatively while AzBio scores improved from 37.7% (13.7%) to 64.1% (22.6%).

Conclusions: Increased cochlear insertion depth allows for high rates of residual acoustic hearing preservation in hybrid cochlear implant candidates. Surgeons should consider using the slim 20 in hybrid CI patients.