Testing a Cochlear Implant Electrode Insertion Training System for Optimal Electrode Array Placement in Different...

Successful intracochlear placement of the cochlear implant (CI) electrode array is a key surgical step in cochlear implantation. Without it, rehabilitation cannot proceed, and all pre- and postoperative efforts are futile. Therefore, electrode insertion requires a high level of precision and devotion from the surgeon. Since clinical and anatomical conditions vary, intensive training to optimally and safely place the electrode array inside the cochlea is essential. During residency, every trainee surgeon should undergo a defined amount of lab training. Drilling cadaveric temporal bones to safely reach the cochlea and optimally insert CI electrodes, as in reconstructive middle ear surgery, is crucial. According to the literature, around 10-20% of individuals with congenital hearing loss are reported to have various degrees of inner ear malformation. Cadaveric temporal bones used for drilling training are typically obtained from elderly donors and rarely show inner ear malformations. In contrast, patients receiving cochlear implants represent a highly selected group in whom anatomical variations of the inner ear are significantly more common than in the general population. Lack of training in placing electrodes in malformed inner ears is seen as one of the key reasons for encountering complications during electrode insertion. The present work is a demonstration study to evaluate an advanced electrode insertion training system featuring interchangeable transparent inner ear models that represent both normal and anatomically variant cochleae. Included anatomical types are incomplete partition (IP) types I, II, and III, as well as cochlear hypoplasia, common cavity, enlarged vestibular aqueduct (EVA), and normal inner ear anatomy, represented in three different sizes. The aim of this study is to demonstrate the use of the presented electrode insertion training system and to provide experiential recommendations on optimal electrode placement inside the cochlear portion across different types of inner ear anatomy, derived from four resident surgeons supervised and guided by an experienced surgeon.