Prediciton of the Round Window Visibility Through Posterior Tympanotomy by CT Scan Analysis

It is difficult to predict the intraoperative visibility of the round window through the posterior Tympanostomy. In case of non-visualization, the surgeon may have to change operative technique during cochlear implant surgery. The primary purpose of the study is to define relevant CT measurements on the preoperative scanner to predict the perioperative visibility of the round window. Define relevant CT measurements on the preoperative scanner to predict the perioperative visibility of the round window. The secondary purpose is to validate the investigator's scanner reading protocol for a prospective study.