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Updated: Jul 3, 2026
Robotic Cochlear Implantation for Direct Cochlear Access
Published on: June 16, 2022
Optimizing Cochlear Implant Outcomes: A Comparison of Lateral Wall and Perimodiolar Electrodes at NextSense Cochlear
Praween Senanayake1,2, Alon Taylor1,2, Kerry Hitos2,3
1Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney.
Background:
Preserving residual low-frequency hearing has become a crucial goal in cochlear implantation, particularly for candidates eligible for electro-acoustic stimulation. Electrode array design is thought to influence the degree of cochlear trauma and hearing preservation, but direct comparisons between slim perimodiolar (PM) and lateral wall (LW) electrodes remain limited.
Aims:
To compare hearing preservation outcomes between new generation PM and LW electrodes in adult cochlear implant recipients and identify clinical predictors associated with successful preservation.
Methods:
A retrospective cohort study was conducted at the NextSense Cochlear Implant Centre, Sydney, involving 333 adults implanted between 2015 and 2021. All had normal cochlear anatomy and preoperative low-frequency four-frequency pure-tone averages (FFPTA) ≤80 dB HL. Patients received either LW (CI522/622, n=244) or PM (CI532/632, n=89) arrays. Hearing preservation was defined as a postoperative threshold shift ≤20 dB at FFPTA or 250 Hz, or any measurable hearing. Regression and ROC analyses were used to identify predictors.
Results:
Hearing preservation rates, defined as a ≤20 dB postoperative shift in the four-frequency pure tone average (0.25, 0.5, 1, and 2 Hz), were similar between groups (36.3% LW vs. 36.4% PM, P =0.992). Both groups experienced significant threshold shifts at 250 Hz (LW: 33.2 dB; PM: 31.2 dB; P <0.0001). Age was a significant negative predictor of hearing preservation in the PM group ( P =0.0079) but not in the LW group. Poorer preoperative FFPTA was positively associated with preservation in both groups.
Conclusions:
Hearing preservation is achievable with both PM and LW electrodes, with comparable outcomes. Age and baseline thresholds influenced preservation, highlighting the need for individualised electrode selection.
