Cochlear implantation and inner ear malformations
Reviewed by Sunil Sharma

In this study the authors attempted to compare the outcomes in children who underwent cochlear implantation (CI) with inner ear malformations to those that had normal inner ear anatomy. Sixty three children with prelingual deafness who underwent CI were included. Twelve of these patients had inner ear malformations including enlarged vestibular aqueduct, a common cavity, incomplete partition, and cochlear hypoplasia. Outcomes were measured at intervals up to two years post-surgery (pre-operatively, and at six, 12, and 24 months post-operatively) using the Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores. In both groups the CAP and SIR scores increased with time after implantation, and there was no significant difference in the scores between the two groups at any of the four follow-up assessments. The authors compare the results to other studies, which have suggested limited improvement in patients with CI with inner ear abnormalities. These papers hypothesise that there are reduced spiral ganglion cell numbers in patients with inner ear malformations, and therefore CI is not as effective. The authors hypothesise that the reason for their seemingly good outcomes may be the fact that they have selected a group of children early in their development, as compared to some other studies. This paper demonstrates that CI in children with inner ear malformations can be of similar benefit to CI in children with normal inner ears if performed early enough in a child’s development.

Evaluation of cochlear implantation in children with inner ear malformations. 
Zhou H, Sun X, Chen Z, et al.
B-ENT
2014;10:265-9.