Narrow, duplicated internal auditory canal.
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.
Serviço de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva 2801-951, Almada, Portugal. teresaandreia@yahoo.com
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Ferreira
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Shayestehfar
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Lufkin
D007758:Ear, Inner / Q000002:abnormalities*; D005154:Facial Nerve / Q000033:anatomy & histology; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014057:Tomography, X-Ray Computed; D000159:Vestibulocochlear Nerve / Q000002:abnormalities