Conclusions We have demonstrated that an automated insertion tool (a.k.a. robot) can be used to duplicate a complex surgical motion in inserting cochlear implant electrode arrays via the “advance-off-stylet” technique (AOS). As compared to human operators, the forces generated by the robot were slightly larger but the robot was more reliable (i.e. less force maxima). Objectives We present force data collected during cochlear implant electrode insertion by human operators and by an automated insertion tool (a.k.a. robot). Methods Using a three-dimensional, anatomically-correct, translucent model of the scala tympani chamber of the cochlea, cochlear implant electrodes were inserted either by one of three surgeons (26 insertions) or by the robotic insertion tool (8 insertions). Force was recorded using a load beam cell calibrated for expected forces of less than 0.1 Newtons. The insertions were also videotaped to allow correlation of force with depth of penetration into the cochlea and speed of insertion. Results Average insertion force by the surgeons was 0.004±0.001N and for the insertion tool 0.005±0.014N (p < 0.00001, Student’s t-test). While the average insertion force of the automated tool was larger than that of the surgeons, the surgeons did have intermittent peaks during the AOS component of the insertion (between 120° and 200°).

The automated insertion tool has proven its capability to perform electrode insertions with final insertion depth angles within the target range of a standard cochlear implant surgery. Additionally, to the knowledge of the authors, it represents the only possibility to automatically insert cochlear implant electrodes via minimally invasive approaches.

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.

The quality of hearing restored to a deaf patient by a cochlear implant in hearing preservation cochlear implant surgery (and possibly also in routine cochlear implant surgery) is believed to depend on preserving delicate cochlear membranes while accurately inserting an electrode array deep into the spiral cochlea. Membrane rupture forces, and possibly, other indicators of suboptimal placement, are below the threshold detectable by human hands, motivating a force sensing insertion tool. Furthermore, recent studies have shown significant variability in manual insertion forces and velocities that may explain some instances of imperfect placement. Toward addressing this, an automated insertion tool was recently developed by Hussong et al. By following the same insertion tool concept, in this paper, we present mechanical enhancements that improve the surgeon’s interface with the device and make it smaller and lighter. We also present electomechanical design of new components enabling integrated force sensing. The tool is designed to be sufficiently compact and light that it can be mounted to a microstereotactic frame for accurate image-guided preinsertion positioning. The new integrated force sensing system is capable of resolving forces as small as 0.005 N, and we provide experimental illustration of using forces to detect errors in electrode insertion.

Conclusions-We have demonstrated that an automated insertion tool (a.k.a. robot) can be used to duplicate a complex surgical motion in inserting cochlear implant electrode arrays via the "advance-off-stylet" technique (AOS). As compared to human operators, the forces generated by the robot were slightly larger but the robot was more reliable (i.e. less force maxima). Objectives-We present force data collected during cochlear implant electrode insertion by human operators and by an automated insertion tool (a.k.a. robot). Methods-Using a three-dimensional, anatomically-correct, translucent model of the scala tympani chamber of the cochlea, cochlear implant electrodes were inserted either by one of three surgeons (26 insertions) or by the robotic insertion tool (8 insertions). Force was recorded using a load beam cell calibrated for expected forces of less than 0.1 Newtons. The insertions were also videotaped to allow correlation of force with depth of penetration into the cochlea and speed of insertion. Results-Average insertion force by the surgeons was 0.004±0.001N and for the insertion tool 0.005±0.014N (p < 0.00001, Student's t-test). While the average insertion force of the automated tool was larger than that of the surgeons, the surgeons did have intermittent peaks during the AOS component of the insertion (between 120° and 200°).