**1. Introduction**

Robotics in otology has overtaken other fields of head and neck surgery and has been developing in many directions for more than two decades. Robots for otology can be classified as collaborative when intervention is constrained by the robot but the surgeon directly actuates the end-effector, teleoperated when a remotely controlled robot enables the tremor reduction, or autonomous when the surgeon monitors the robot performing a task [1–3]. Current clinical trials focus on more accurate stapes surgery, minimally invasive access to the cochlea and less traumatic insertion of cochlear implant (CI) electrode arrays. A robot-based holder may combine the benefits of endoscopic exposure with a two-handed technique. Robot-assisted endoscopy is a safe and trustworthy tool for several categories of middle ear procedures, such as myringoplasty, partial ossiculoplasty and total ossiculoplasty [4,5]. Robot-assisted manipulation of the ossicular chain in cadaveric temporal bones using a robotic arm (RobOtol®) was described as reliable [6]. Otosclerosis surgery with robotic assistance enhances the precise amplitude of motion and the surgeon's

**Citation:** Gaw ˛ecki, W.; Balcerowiak, A.; Podlawska, P.; Borowska, P.; Gibasiewicz, R.; Szyfter, W.; Wierzbicka, M. Robot-Assisted Electrode Insertion in Cochlear Implantation Controlled by Intraoperative Electrocochleography— A Pilot Study. *J. Clin. Med.* **2022**, *11*, 7045. https://doi.org/10.3390/ jcm11237045

Academic Editor: Nicolas Guevara

Received: 4 November 2022 Accepted: 21 November 2022 Published: 29 November 2022

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dexterity and rapidly reduces the learning curve [7]. Moreover, the surgical simulator has been developed to plan new procedures that exploit the robot's capacities, enhancing gesture accuracy and allowing exploration of new procedures for middle ear surgery [8].

Robot-assisted cochlear implantation is the result of over a decade of research & development work but is still in its childhood era [9,10]. Successful hearing rehabilitation with a CI is a complex, multi-stage process. "Clinical Practice Guidelines" are widely accepted for the standardization of such processes; however, there is still room for refining the diagnostic and technical steps for optimal results, which is where robotic surgery comes in [11]. As the first device to obtain European certification for clinical use (CE mark), the RobOtol® system has been used in France and China since 2019 for robotic-assisted CI in profoundly deaf adults and children [5,6,12]. The beginning of research dates back to 2005, the commercial launch of RobOtol® on the market in 2018 and soon after, in 2019, the first robotic cochlear implantation at the APHP Pitié-Salpêtrière Department took place. Recently the robotic system has been implemented in clinical practice [6,12–14] and the assumption was optimization of the electrode array insertion into the scala tympani (ST). The subject of discussion and the key question is how to compare and how to measure the superiority of a robotic electrode insertion over a manual one. This was performed based on the analysis of retrospective (manual insertion) and prospective (robotic) pair-matched patients based on imaging studies and on the results of speech rehabilitation [12–14].

One method of accurately assessment of electrode array placement in the cochlea is intracochlear electrocochleography (ECochG) [15,16]. Intracochlear ECochG is also a promising method for pre-curved electrodes [17]. In general, ECochG is a measurement technique based on recording electrical potentials generated by the inner ear and auditory nerve in response to acoustically evoked stimulation [18]. Contrary to the well-known and described standard extracochlear ECochG measurement techniques that require the use of surface electrodes, trans-tympanic or extra-tympanic electrodes, in intracochlear ECochG measurement application, the CI electrode array is used as the measuring electrode [17]. The ECochG response to low-frequency tone burst stimulus is mainly composed of the cochlear microphonic (CM) and the auditory nerve neurophonic (ANN) [19]. The CM is derived from the stereocilia of the outer hearing cells and follows the stimulus waveform [20]. The ANN is the electric potential correlate of phase-locking in the auditory nerve [19]. Therefore, monitoring of extracted CM electrical potentials allows indirect insight into the inner ear's micromechanical activity and provides data for assessing electrode insertion trauma during the electrode array insertion and after cochlear implantation at subsequent follow-ups. Previous work has also demonstrated that ECochG recordings correlate with postoperative pure-tone thresholds in subjects with sensorineural hearing loss [21]. Additionally, CI recipients who show preserved residual hearing perform better than those without postoperative hearing [22].

Thus, we evaluated the use of the RobOtol® otologic robot to insert CI electrodes into the inner ear with intraoperative ECochG (iECochG) analysis. The objective of the study was to clarify how the iECochG can improve the robotic cochlear electrode array insertion.
