Predicting Round Window Niche Visibility via the Facial Recess Using High-Resolution Computed Tomography

Abstract

The RWN visibility and the preoperative HRCT findings showed a high correlation. Drawing the prediction line is a simple and useful way for preoperatively predicting the RWN visibility in cochlear implant surgery.

Radiological parameters related to success of the round window approach in cochlear implantation: A retrospective study

“…In the present study, the angle was significantly wider in the RW group than that in the PC group and independent factor of selection or success of the RW approach. This result coincides well with those of another study reporting that the angle of the posterior EAC relative to the cochlear basal turn is significantly smaller in patients with poor intraoperative RW niche visibility compared with patients with good RW niche visibility …”

“…However, we observed that the width of the facial recess did not differ significantly between the RW and PC groups. Kashio et al reported a similar finding that intraoperative RW niche visibility was not associated with facial recess width. These results suggest that the width of the facial recess is not a determinant for selecting the surgical approach for CI surgery.…”

Surgical Anatomy of the Human Round Window Region

“…Others have studied cochlear anatomy for cochlear implantation; n ¼ 22 (9), n ¼ 9 (18), n ¼ 16 (19), n ¼ 10 (20), and n ¼ 40 (21). RW niche visibility through the facial recess and the ability to predict its visibility through preoperative CT has been reported based on the study of 70 surgical cases (22). The RW's accessibility for cochlear implant insertion has also been studied in 50 surgical cases (23).…”

A Novel Classification: Anomalous Routes of the Facial Nerve in Relation to Inner Ear Malformations

“…As it is not always possible to visualize the chorda tympani in HRCT sections, the distance between the external auditory canal (EAC) and FN is used to determine the width of the FR. 11 The FR evaluated in axial HRCT scans is classified as follows: Type 1, normal FR/normal mastoid segment. If the space between the EAC and the FN is >2 mm, the width of the FR is accepted as normal.…”

“…The FR is considered narrow if the distance between the EAC and the mastoid segment of the FN is <2 mm. 11 Type 3, unclassified. The mastoid segment could not be visualized and followed in cases of cochlear aplasia, Michel deformity, CC, or rudimentary otocyst, as there was no accurate radiological landmarks.…”