Role of Multislice CT Imaging in Predicting the Visibility of the Round Window in Pediatric Cochlear Implantation.

Abstract

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). To find an applicable way by HRCT imaging for the prediction of the visibility of the RW during cochlear implantation (CI) surgery. Five radiologic measurements were performed on the axial HRCT and these measurements were correlated with the degree of RW visibility after performing posterior tympanotomy during CI surgery. Sixty ears of 60 children were included in the current study. A significant correlation was found between the degree of RW visibility and the following: 1) the angle between RW, facial nerve (FN), and the coronal axis (p < 0.00001); 2) the vertical distance between RW and FN (p = 0.006552); and 3) FN location to the axis of cochlea (p = 0.000419). On the other hand, nonsignificant correlation was found between the degree of RW visibility and both of the facial recess width and the angle between axis of cochlea and external auditory canal (p = 0.941363 and p = 0.59036 respectively). The angle between RW, FN, and the coronal axis and the vertical distance between RW and FN are proportionate with the degree of surgical RW visibility in children during CI. In children, surgeons can depend on those two parameters in addition to the distance between FN location to the axis of cochlea in predicting the RW visibility rather than depending on the measurements related to the external auditory canal.