title: Bilateral narrow duplication of the internal auditory canal.
abstract: OBJECTIVE
  To demonstrate diagnostic imaging of an extremely rare presentation of bilateral narrow duplication of the internal auditory canal.
  
  
  METHODS
  An adolescent boy with profound sensorineural hearing loss presented for hearing rehabilitation. Imaging studies (i.e. multidetector computed tomography and magnetic resonance imaging) clearly demonstrated bilateral duplication of the internal auditory canals, with narrowing of the lower canals, unilateral cochlear and vestibular dysplasia, bilateral superior semicircular canal malformation, and bilateral absence of the posterior semicircular canals.
  
  
  CONCLUSIONS
  To our knowledge, this is only the third such case described in the literature. Considering that the vestibulocochlear nerve has been unable to be demonstrated in almost all cases of duplicated internal auditory canal (unilateral and bilateral), our case supports the hypothesis that vestibulocochlear nerve aplasia or hypoplasia leads to internal auditory canal stenosis. We consider this rare presentation of bilateral narrow duplication of the internal auditory canal to represent a contraindication for cochlear implantation.
authors.affiliation: Department of Radiology, DAPI-Diagnóstico Avançado por Imagem, Curitiba, PR Brazil.
authors.forename: L O M
authors.initials: LO
authors.lastname: Coelho
authors.forename: S E
authors.initials: SE
authors.lastname: Ono
authors.forename: A Carvalho
authors.initials: AC
authors.lastname: Neto
authors.forename: J F
authors.initials: JF
authors.lastname: Polanski
authors.forename: M
authors.initials: M
authors.lastname: Buschle
mesh_terms: D000158:Acoustic Impedance Tests; D000293:Adolescent; D001299:Audiometry; D019929:Cochlear Implantation; D000075202:Contraindications; D007758:Ear, Inner / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006312:Hearing Loss, Bilateral / Q000151:congenital*; D006319:Hearing Loss, Sensorineural / Q000151:congenital*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D035583:Rare Diseases / Q000175:diagnosis; D013701:Temporal Bone / Q000002:abnormalities*; D014057:Tomography, X-Ray Computed / Q000379:methods; D000159:Vestibulocochlear Nerve / Q000002:abnormalities*