Cochlear implantation in children with congenital inner ear malformations

This retrospective study included 18 children with congenital inner ear malformations received cochlear implantation. Nine cases had classical Mondini anomalies, 4 large vestibular aqueduct syndrome, 3 semicircular canal aplasia and the remaining 2 inner auditory canal anomaly and cochlear hypoplasia. The congenital inner ear malformations consisted 17% in all 108 children receiving cochlear implants. Fifteen cases underwent cochlear implantation with posterior tympanotomy via mastoid cavity. On the other hand, 3 cases with middle ear malformations, including hypoplasia of the mastoid cavity, required trans-external auditory canal approach, and one of them showed an abnormal route of the facial nerve. Although cerebrospinal fluid leakage was encountered during cochleostomy in 4 cases, none of them required middle ear cavity obliteration or spinal drainage. Seven cases, including Mondini anomaly, semicircular canal dysplasia and cochlear hypoplasia, showed no electrically evoked compound action potential in intra-operative neural response telemetry (NRT) measurements. Speech recognition tests at 2 years after implantation showed good results except for 2 children with semicircular canal aplasia and one of the Mondini anomaly cases.