Combined preoperative HRCT parameters for prediction of round window visibility in pediatric cochlear implant patient

Various approaches to the round window for cochlear implantation: a systematic review

“…Furthermore, the high-resolution CT measurements had an overall sensitivity and specificity of 92.3 per cent and 96.2 per cent, respectively, for predicting the round window niche 52 and a sensitivity and specificity of 91.4 per cent and 88.6 per cent, respectively, for predicting round window visibility. 53…”

“…Moreover, performing a pre-operative CT may allow for a better prediction of round window visualisation, and one study recommended using the Kashio line, which is a facial recess width with a cut-off value equal to or more than 4.75 mm, and round window location with a cut-off value equal to or more than 2.95 mm. 53 Another study 52 found an inverse relationship between round window niche visualisation and the distance between the fossa ambos and round window niche: the shorter the distance, the more difficult visualising the round window niche became. The shorter distance could be explained by the anatomical variation of round window niche displacement either posteriorly or superiorly and the displacement of the tip of the short process of the incus.…”

“…24,38,45 Endoscopic-assisted techniques were also described for use in the classic posterior tympanotomy or endomeatal approaches. 4,17,[46][47][48][49][50] Prediction of round window visibility using CT was described in seven articles using various radiological parameters, 9,19,22,[51][52][53][54] with a reported sensitivity of up to 92.3 per cent and specificity of up to 96.2 per cent in determining the actual visualisation of the round window niche (Table 2). 52 We also reviewed the audiological and speech outcomes of the included cases with the round window approach.…”

“…Furthermore, the high-resolution CT measurements had an overall sensitivity and specificity of 92.3 per cent and 96.2 per cent, respectively, for predicting the round window niche 52 and a sensitivity and specificity of 91.4 per cent and 88.6 per cent, respectively, for predicting round window visibility. 53 In one study using multislice CT, 22 the prediction of round window membrane visibility through the posterior tympanotomy had a sensitivity of 65.71 per cent and a specificity of 96.15 per cent. In another study that used oblique sagittal-cut CT scanning, 54 the mean distance from the facial bony canal to the round window and from the facial nerve to the round window was longer than the distances observed using the operative view.…”