Deeper Insertion Is Associated with Improved Performance in Perimodiolar Cochlear Implants After Controlling Cochlear Health

Sunday, October 18, 2026

1:30 PM - 1:36 PM PT

Location: West Exhibit Hall A, Learning Zone 1

Presenting Author(s)

JB

James Bao, MD

Resident Physician
Washington University/B-JH/SLCH Consortium
Saint Louis, Missouri, United States

Co-Author(s)

AW

Amit Walia, MD

Neurotology Fellow
Washington University/B-JH/SLCH Consortium
St. Louis, MO, United States
SL

Shannon M. Lefler, AuD

Lecturer in Audiology and Communication Sciences
Washington University School of Medicine, United States
Jordan J. Varghese, MD

Resident Physician
Washington University/B-JH/SLCH Consortium
Saint Louis, MO, United States
ND

Nedim Durakovic, MD

Associate Professor
Washington University School of Medicine
Saint Louis, MO, United States
JH

Jacques A. Herzog, MD

Professor of Otolaryngology—Head & Neck Surgery
Washington University School of Medicine
Creve Couer, MO, United States

Senior Author(s)

Matthew A. Shew, MD

Assistant Professor
Washington University School of Medicine
St. Louis, MO, United States

Disclosure(s):

Nedim Durakovic, MD:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Introduction: Electrode position and cochlear health are known predictors of cochlear implant (CI) outcomes. We aimed to assess the impact of angular insertion depth (AID), wrap factor (WF), and electrode location on speech perception outcomes of slim perimodiolar CIs while controlling for cochlear health.

Methods: This is a retrospective cohort study of 184 post-lingually deafened adults receiving slim perimodiolar CIs between 2020 and 2025. Intracochlear post-insertion electrocochleography total response (ECochG-TR) was used to quantify cochlear health. Postoperative 3D reconstructed computed tomography was used to assess WF (modiolar proximity), AID (insertion depth), and electrode location. Performance was assessed with 6 month postoperative consonant-nucleus-consonant (CNC) scores.

Results: WF demonstrated no significant correlation with 6 month CNC (r = -0.10, 95% CI: -0.15 to 0.13) whereas AID had a weak positive correlation (r = 0.26, 95% CI: 0.13 to 0.39). There was no difference in CNC between CIs adjacent to basilar membrane/scala media and those that were not. ECochG-TR and CNC demonstrated a moderate positive correlation (r = 0.53, 95% CI: 0.43 to 0.62) and explained 28% of variance in CNC, although it tended to overestimate performance for shallower insertions. In multivariable regression models controlling for ECochG-TR, AID remained a significant predictor of CNC (R2 = 0.28, p = <.001), with deeper insertion depth associated with higher CNC scores. WF and proximity to basilar membrane/scala media were not significant predictors when controlling for ECochG-TR.

Conclusions: Cochlear health remains an important predictor of CI speech perception. After controlling for variability in cochlear health, greater AID is associated with improved speech perception outcomes, while WF and proximity to basilar membrane/scala media are not significant contributors. This suggests perimodiolar electrode strategies should prioritize achieving deeper insertions while preserving modiolar proximity. Future work is needed to develop more accurate and clinically meaningful metrics for modiolar proximity.