Analysis of Cochlear Parameters in Paediatric Inner Ears with Enlarged Vestibular Aqueduct and Patent Cochlea

Is cochlear implant (CI) electrode selection for cochleae with an enlarged vestibular aqueduct (EVA) the same as that for patent cochleae with a normal inner ear structure? Preoperative high-resolution computed tomography (HRCT) images of 247 ears were assessed retrospectively. The A-value, B-value, and H-value were measured with OTOPLAN, and Bell curves were created to show the distribution. All ears with EVA were re-evaluated using a 3D slicer to confirm whether incomplete partition type II (IP II) existed. The Mann-Whitney U-test was applied to determine a statistically significant difference. After adjustment with the Bonferroni correction method, a p-value <= 0.006 was considered significant. In total, 157 ears with patent cochlea and 90 ears with EVA were assessed. Seventy (82%) of the EVA ears had an IP II malformation, and 14 (19%) of these were not detected by CT scan but were later seen through the 3D reconstruction. A significant difference was found for the A value and B value between the patent cochleae and EVA-only and between the patent cochleae and EVA with IP II. Most EVA cases had an IP II malformation. The basal turn of the cochlea may be smaller in EVA cases than in the patent cochleae. Electrode selection should be adjusted accordingly.

Automated summary

The selection of cochlear implant electrodes is different for cochleae with enlarged vestibular aqueduct (EVA) compared to those with a normal structure. EVA ears often have an incomplete partition type II (IP II) malformation, which may result in a smaller basal turn of the cochlea.