Automated insertion of preformed cochlear implant electrodes: evaluation of curling behaviour and insertion forces on an artificial cochlear model

Abstract

The study confirms the functionality and reliability of the automated insertion tool for insertion of preformed CI. Improved insertion strategies considering patient-specific anatomy become possible.

Force of Cochlear Implant Electrode Insertion Performed by a Robotic Insertion Tool

“…To maximize repeatability and minimize inter-trial variability, an automated insertion technique is necessary. Prior reports have demonstrated that automated cochlear implant electrode insertion with robotic devices is feasible [1, 2, 3, 4, 5, 6, 17]. Using such devices, the authors of these reports have analyzed the cochlear structure and behavior of different types of electrode arrays trying to find optimal insertion trajectories and velocities in terms of patient stress during and electrode position after insertion.…”

Determination of the curling behavior of a preformed cochlear implant electrode array

“…As a positive side effect of this, the variation of bending characteristics could be reduced due to a closely defined initial shape and limitation of clearance. Thereby, the strong influence of the not ideal straight starting configuration, as also emphasized in previous studies [36], could be effectively reduced. Of course, in this case the principle curling behavior had to be determined fundamentally new because the curling of the electrode carrier would be released only outside the guide sleeve.…”

“…It is obvious to apply these technologies also for an accurate insertion of the implant by taking into account the helical shape of the cochlea and adapting the electrode's coiling behavior to it. The automated insertion tool, as described in detail in previous publications [33][34][35][36], offers the necessary technical prerequisite.…”

“…The same goal was successfully achieved by using image-guided surgical systems [21][22][23] as well as a robot assistance device [24][25][26][27]. Due to the geometrical limitations of a drill hole, the minimally invasive approach requires the development of a special insertion tool as presented by our group [33][34][35][36]. This tool can be tracked by the image-guiding system or, alternatively, be positioned by the robot assistant device to compensate for the missing visual control during the insertion process.…”

“…The next step is to hold the stylet stationary, while the electrode array can be advanced off the stylet into the cochlea [37,38]. However, a previous study [36] involving a transparent model of the human scala tympani showed that this recommended intracochlear trajectory of the electrode array cannot be achieved sufficiently in all cases even if the AOS technique is applied, strictly following these general recommendations. Hence, we became interested in the determination of the curling behavior of these electrode arrays to consider these findings in upcoming electrode developments and insertion strategies.…”