Anatomical Features of Children With Mondini Dysplasia: Influence on Cochlear Implantation Performance

Abstract

Objective: To analyze the long-term auditory performance after cochlear implantation (CI) and identify anatomical features of Mondini dysplasia associated with post-CI outcomes.

Study design: Retrospective study.

Setting: Tertiary care academic center.

Patients: We enrolled 49 ears with Mondini dysplasia who underwent CI with more than 7 years of follow-up and age at CI- and sex-matched control group with radiologically normal inner ears.

Main outcomes and measures: The development of auditory skills after CI was evaluated using word recognition scores (WRSs). The anatomical features were measured based on temporal bone computed tomography and magnetic resonance imaging, involving the width of the bony cochlear nerve canal (BCNC), cochlear basal turn, enlarged vestibular aqueduct, cochlear height, and diameter of the cochlear nerve (CN).

Results: CI in ears with Mondini dysplasia showed comparable benefits and improvement of auditory performance to controls during the 7 years of follow-up. In Mondini dysplasia, four (8.2%) ears showed narrow BCNC (<1.4 mm) with poorer WRS (58 ± 17%) than those with normal-sized BCNC, which had WRS (79 ± 10%) comparable to that of the control group (77 ± 14%). In Mondini dysplasia, the maximum ( r = 0.513, p < 0.001) and minimum ( r = 0.328, p = 0.021) CN diameters had positive correlations with post-CI WRS. The maximum CN diameter ( β = 48.347, p < 0.001) and BCNC width ( β = 12.411, p = 0.041) were significant factors that influence the post-CI WRS in multiple regression analysis.

Conclusions: Preoperative anatomical evaluation, especially BCNC status and CN integrity, may serve as predictive markers for post-CI performance.