title: Nervus Intermedius Guides Auditory Brainstem Implant Surgery in Children with Cochlear Nerve Deficiency.
abstract: OBJECTIVE
  To investigate the anatomic features of the nervus intermedius and cranial nerve VII in children with cochlear nerve deficiency and to verify whether the nervus intermedius can provide an additional landmark to help guide placement of the auditory brainstem implant electrode.
  
  
  METHODS
  Case series with chart review.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  High-definition video was captured during retrosigmoid surgery in 64 children (mean age, 3.91 ± 2.83 years) undergoing auditory brainstem implant placement. These videos were examined with particular reference to the number and variety of nervus intermedius bundles and any associated facial nerve anomalies.
  
  
  RESULTS
  Absence of cranial nerves VI, VII, and VIII was observed in 3, 6, and all 64 children, respectively. Fifteen children had several abnormalities of the facial nerve in the cerebellopontine angle. Anatomic identification of the facial nerve and the bundles composing the nervus intermedius was possible in 46 children. In 12 children, identification was possible with the assistance of intraoperative monitoring. The number of bundles composing the nervus intermedius varied from 1 to 6. The nervus intermedius and cranial nerve IX were useful landmarks for identifying the foramen of Luschka of the lateral recess.
  
  
  CONCLUSIONS
  The nervus intermedius provides an additional landmark during auditory brainstem microsurgery since it was identified in all subjects. The nervus intermedius anatomy and its topographic relationship with the neurovascular structures around the foramen of Luschka have been described for the first time in children with cochlear nerve deficiency.
authors.affiliation: Department of Maxillo-facial Surgery, University of Milan, Milan, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Colletti
authors.affiliation: Otological and Skull Base Surgery Department, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Mandalà
authors.affiliation: ENT Department, University of Verona, Verona, Italy.
authors.forename: Liliana
authors.initials: L
authors.lastname: Colletti
authors.affiliation: International Center for Performing and Teaching Auditory Brainstem Surgery in Children, Milan, Italy collettiabi@yahoo.com.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Colletti
mesh_terms: D038262:Auditory Brain Stem Implants; D002675:Child, Preschool; D003056:Cochlear Nerve / Q000002:abnormalities*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000379:methods*; D016343:Monitoring, Intraoperative; D013506:Otologic Surgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D000159:Vestibulocochlear Nerve / Q000473:pathology* / Q000503:physiopathology; D000160:Vestibulocochlear Nerve Diseases / Q000151:congenital / Q000503:physiopathology / Q000601:surgery*; D014741:Video Recording
keywords: anatomy; auditory brainstem implantation; cerebellopontine angle; cochlear nerve aplasia; facial nerve; foramen of Luschka; nervus intermedius; profound deafness