목적: The aims of this study were to introduce the new classification of cochleovestibular malformations (CVMs) and to investigate the factors which determine the outcomes of cochlear implantation (CI) in children with CVMs. 방법:Sixty-four children with CMVs who had used a cochlear implant over 3 years were included. CVMs were classified into 4 subtypes based on the morphology of cochlea and modiolus normal cochlea and intact modiolus (type A, n=18), malformed cochlea and partial modiolus (type B, n=33), malformed cochlea and no modiolus (type C, n=6) and no cochlea and no modiolus (type D, n=7). Speech perception test scores were compared among the subtypes of CVMs using analysis of covariance with post-hoc Bonferroni test. The multivariate regression analysis was employed to investigate the significant prognostic factors determining speech perception test scores. 결과:The speech perception test scores of children with CVM type A and B were significantly better than those of children with CVM type C and D, and were not significantly different from those of the implanted children with normal inner ear morphology. Multivariate regression analysis revealed that the age at CI and cochlear nerve size were significant factors that determine the speech perception test scores in implanted children with CVMs. Significant trend was observed in the prevalence of cochlear nerve deficiency from CVM type A to type D. 결론:The new classification of CVMs based on the morphology of cochlea and modiolus was simple and easy to apply, and well correlated with post-CI performance and cochlear nerve status. The new classification of CVM using TBCT is helpful in the preoperative evaluation of children with CVM.