Cochlear Implant Insertion Routes and Intra-operative Electrophysiological Measurements: A Retrospective Analysis at...

Area of Science:

• Otolaryngology
• Neurosurgery
• Biomedical Engineering

Background:

• Cochlear implant (CI) surgery utilizes various routes: Round window (RW), Extended Round Window (Ext RW), and Cochleostomy (C).
• Optimal intracochlear electrode placement is vital for successful CI outcomes.
• Intraoperative electrophysiological testing, including impedance and Electrically Evoked Auditory Nerve Action Potentials (ECAP), assesses device function and electrode positioning.

Purpose of the Study:

• To compare intraoperative electrophysiological measurements (impedance and ECAP) for auditory nerve stimulation across three CI electrode insertion routes.
• To determine if surgical approach influences neural response characteristics.

Main Methods:

• Retrospective analysis of 47 CI recipients over 4 years.
• Patients categorized into full-banded and half-banded electrode groups.
• Intraoperative impedances and ECAP measured at specific electrodes (E5, E10, E15, E20) across different stimulation modes and insertion routes.

Main Results:

• In the half-banded group, impedance values showed no significant differences across surgical routes for any electrode or stimulation mode.
• In the full-banded group, impedance at electrode E5 differed significantly for the Cochlear (CG) stimulation mode.
• No other statistically significant differences in impedance were found for other modes in the full-banded group across the three routes.

Conclusions:

• No statistically significant differences in intraoperative impedance and ECAP measurements exist between full-banded and half-banded electrodes across the three surgical routes.
• All three surgical approaches (RW, Ext RW, C) appear to provide comparable auditory nerve stimulation.
• CI surgeons can select electrode insertion routes based on surgical anatomy, implant type, and surgeon preference.