An observational, prospective study to evaluate the preoperative planning tool "CI-Wizard" for cochlear implant surgery.

"CI-Wizard" is a new, three-dimensional software planning tool for cochlear implant surgery with manual and semi-automatic algorithms to visualize anatomical risk structures of the lateral skull base preoperatively. Primary endpoints of the study represented the evaluation of the CI-Wizards usability, accuracy, subjectively perceived and objectively measured time in clinical practice. In a period from January 2014 to March 2015, n = 36 participants were included in this study. These members were divided into three groups of equal number (n = 12), but different level of experience. Senior doctors and consultants (group 1), residents (group 2) and medical students (group 3) segmented 12 different CT-scan data sets of the CI-Wizard (four per participant). In total, n = 144 data sets were collected. The usability of the CI-Wizard was measured by the given questionnaire with an interval rating scale. The Jaccard coefficient (JT) was used to evaluate the accuracy of the anatomical structures segmented. The subjectively perceived time was measured with an interval rating scale in the questionnaire and was compared with the objectively mean measured time (time interact). Across all three groups, the usability of the CI-Wizard has been assessed between 1 ("very good") and 2 ("with small defects"). Subjectively, the time was stated as "appropriate" by questionnaire. Objective measurements of the required duration revealed averages of t = 9.8 min for creating a target view. Concerning the accuracy, semi-automatic anatomical structures such as the external acoustic canal (JT = 0.90), the tympanic cavity (JT = 0.87), the ossicles (JT = 0.63), the cochlea (JT = 0.66), and the semicircular canals (JT = 0.61) reached high Jaccard values, which describes a great match of the segmented structures between the partcipants and the gold standard. Facial nerve (JT = 0.39) and round window (JT = 0.37) reached lower Jaccard values. Very little overlap tendency was found for the chorda tympani (JT = 0.11). This software program represents a further important step in the development of preoperative planning tools in cochlear implant surgery. The study revealed a high level of satisfaction in the usability. The subjectively required time was considered as "appropriate" and the objectively mean measured time was t = 9.8 min short enough, so that a clinical application seems realistic. Particularly for semi-automatically segmented structures, it represented a good accuracy. For purely manual segmented structures, further improvements are desirable. Finally, this program also provides a good learning tool for medical students and residents to become familiar with the anatomy of the lateral skull base.