Cochlear Implant Electrode Array Position Monitored During CI Surgery with Fluoroscopy, Electrocochleography and Evoked Compound Action Potentials

Background

During the last years more and more patients with residual hearing receive a cochlear implant. Several factors have been identified that reduce the residual hearing after CI surgery. This study investigated if trauma during the insertion of the electrode array or a mechanical resistant of the array in the scala may cause a loss.

Objective

Objectives of this study are to identify movements of the electrode array during insertion that may cause a loss of hearing and may identify a more ideal placement of the electrode array (lateral, medial).

Methods

For eight adult patients the Electrocochleography (ECochG) responses were measured during insertion of the electrode array of a Cochlear™ Nucleus® Profile with Slim Modiolar Electrode (CI532). At the same time fluoroscopy was done to analyze the movement of the array and synchronize the movement with the measurements. After complete insertion different electrode positions were achieved and measured with ECochG and Evoked Compound Action Potential (ECAP).

Results

The ECAP show a clear difference between electrode position more lateral versus medial. The ECochG measurements are difficult to interpret at that stage, more data is required and shall be available at the time of the presentation.

Conclusions

ECochG, ECAP and fluoroscopy are important tools to understand the mechanisms during electrode array insertion, possible trauma detection and optimizing of electrode placement.