Round Window Dissection and Cochlear Implantation

Abstract

Hearing loss (HL) is a major health problem with a significant impact on the affected individuals and their communities. Patients who suffer from severe and profound hearing loss get little or no benefit from hearing aids and may require cochlear implantation. Besides the traditional transmastoid posterior tympanotomy approach, in particular cases of middle-ear malformations or anatomical anomalies at the level of the facial nerve or round window region, or in case of inflammatory tissue inside the middle-ear cavity, an endoscope-assisted cochlear implantation (suprameatal approach) could be used to overcome these difficulties. The ovine model represents a viable training model in this field, due to the possibility to improve the capacity of drilling under endoscopic view through the external auditory canal (EAC) and to understand the gestures that can help during human live surgery. The ovine model is characterized by some differences, if compared to human specimens for this approach. Indeed, the narrow ear canal restricts the instrumental manipulation especially during drilling of the canal wall. Furthermore, difficult identification of the round window can be faced in case it extends deeply behind the posterior meatal wall. Additionally, the non-availability of proper electrode arrays fitting the ovine cochlea makes the insertion process harder. These aspects imply that this kind of training might be useful to get experience in performing this technique, avoiding surgical mistakes and lessening surgical operative times on live surgery. This chapter will highlight the potential of the ovine model in endoscopic round window region dissection and cochlear implantation training in order to let the reader improve the surgical skills and then transfer these skills during live surgical approaches.