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Updated: Aug 11, 2026

Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual
Published on: January 11, 2018
Narrow, duplicated internal auditory canal
T Ferreira1, B Shayestehfar, R Lufkin
1Serviço de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva 2801-951, Almada, Portugal. teresaandreia@yahoo.com
Abstract:
A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve.
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