Role of HRCT imaging in predicting the visibility of Round window (RW) on patients underwent cochlear implant surgery

Introduction High-resolution computed tomography (HRCT) magnifies the role of preoperative imaging for detailed inner and middle ear anatomical information and enhances more efforts for better dependent correlation and measurements of round window (RW). Objectives The aim of this study was to find an appropriate way by HRCT imaging for the prediction of the visibility of the round window during cochlear implant (CI) surgery. Methods The study was conducted using hospital information from patients referring the Khuzestan Cochlear Implant Center (2017–2018). 87 patients underwent cochlear implant surgery, 56 patients with high resolution CT scans were included in the study. All patients underwent surgical treatment via posterior tympanotomy approach. Results 56 patients were examined. Patients were divided into three groups: children (0–12 years) and adolescence (18-13 years) and adults (19–59 years), of whom 45 patients (80.4%) were children, and 3 patients were adolescence (5.4%) and 8 patients (14.3%) were adults. 22 patients (39.3%) were fully visible and 13 patients (23.2%) were partially visible and 21 (37.5%) patients were difficult to visualize. In high-resolution imaging studies, mastoid 2 cases (3.6%) were poorly aerated and 8 cases (14.3%) were moderately aerated and 46 (86.1%) were well aerated. The amount of round window overhanging in 43 patients (76.8%) was 4.4 and in 12 patients (21.4%) was 3.4%. Conclusion The presence of the air cell around the facial recess may provide easier access to the facial recess. There was a significant relationship between the RW in the operation and the angle between the RW and the facial nerve and the coronal axis. There is no significant relationship between the visibility of the RW and the facial recess, Vertical height RW and facial nerve (FN), the distance between the FN and the posterior canal in the axial, the angle between the FN and inner margin of RW, and the angle between the FN and the tympanic annulus with the inner margin RW in the Axial and FRL was not found.