Preoperative radiologic evaluation in cochlear implantation

Abstract

Aim of study: Assess the value of computed tomography (CT) in the evaluation of abnormalities in the cochlea and auditory pathways.

Material and methods: We used CT to evaluate 108 children before cochlear implantation surgery. Children's ages at implantation ranged from 21 months to 16 years (mean age, 5.4 years). The etiology of deafness was meningitis in 44 children (40.8%), congenital in 51 (47.2%), and other in 13 children (12%).

Results: Eighteen of the 108 (16.6%) children and 34% of the postmeningitic children were found to have at least partial obliteration of the cochlea. Two (2%) children had congenital malformations of the cochlea and 12 children (11.1%) had abnormalities in the brain CT-scan. CT diagnostic values in postmeningitic children regarding cochlear obliteration were accuracy, 75%; sensitivity, 62%; specificity, 82%; positive predictive value, 66.6%; and negative predictive value, 79.3%. In six (20.6%) of postmeningitic children with normal CT-scans, some scala tympani drillout was required.

Conclusion: CT-scan is capable neither of predicting with certainty the presence of minor degrees of cochlear obliteration nor of specifically imaging either the auditory nerve or its central connections.