Postmeningitic ossification in pediatric cochlear implantation

OBJECTIVE: The goals of this study were to retrospectively review high- resolution CTs (HRCTs) of pediatric postmeningitic cochlear implant recipients and to correlate results with surgical findings. METHODS: HRCTs of 20 children (11 months to 12 years old) who underwent implantation with multichannel devices were reviewed. Results were correlated with the degree of ossification observed at surgery. RESULTS: Ninety percent of subjects required drilling of ossified bone within the basal turn at surgery. HRCT of the cochleas suggested ossification within the basal turn in 45% (50% sensitivity). Ossification of the lateral semicircular canal on HRCT was present in 72% (77% sensitivity). Five of 6 cases without radiographic evidence of ossification had positive findings at surgery. CONCLUSION: Ossification is a common occurrence in postmeningitic deaf children. Ossification of the lateral semicircular canal on HRCT is a more sensitive measure for predicting ossification than evidence of cochlear involvement. Absence of ossification on HRCT is no guarantee of cochlear patency at the time of implantation.