title: Auditory brainstem implantation: anatomy and approaches.
abstract: BACKGROUND
  Auditory brainstem implantation at the cochlear nuclei used mainly for neurofibromatosis type 2 patients with bilateral loss of the cochlear nerves has more recently been extended to the inferior colliculus.
  
  
  OBJECTIVE
  To examine the microsurgical and endoscopic anatomy of the cochlear nuclei and inferior colliculus as seen through the translabyrinthine and retrosigmoid approaches used for cochlear nuclei and inferior collicular implantation.
  
  
  METHODS
  Ten cerebellopontine angles of formalin-fixed adult cadaveric heads were examined with the aid of the surgical microscope and endoscope. The ascending auditory pathways between the cochlear nuclei and inferior colliculi and above were examined by the fiber dissection technique.
  
  
  RESULTS
  Both the translabyrinthine and retrosigmoid routes provide sufficient exposure for concurrent tumor removal and implantation at either the cochlear nuclei or inferior colliculus. The position of the inferior colliculus in the auditory pathways and its accessibility in the infratentorial supracerebellar exposure directed through either the translabyrinthine or retrosigmoid approach makes it an alternative site for electrode placement if the cochlear nuclei are not functionally or structurally suitable for implantation. Endoscopic assistance may aid the exposure and electrode placement at either site.
  
  
  CONCLUSIONS
  The translabyrinthine or retrosigmoid approaches provide access to the cochlear nuclei for implantation and also to the inferior colliculus through the translabyrinthine or retrosigmoid infratentorial supracerebellar route. The endoscope may aid in exposing either site.
authors: *Department of Neurosurgery, University of Florida, College of Medicine, Gainesville, Florida; ‡Department of Neurosurgery, Fukuoka University, Fukuoka, Japan.
authors: Noritaka
authors: N
authors: Komune
authors: Kaan
authors: K
authors: Yagmurlu
authors: Satoshi
authors: S
authors: Matsuo
authors: Koichi
authors: K
authors: Miki
authors: Hiroshi
authors: H
authors: Abe
authors: Albert L
authors: AL
authors: Rhoton
mesh_terms: D000328:Adult; D038263:Auditory Brain Stem Implantation / Q000379:methods*; D002102:Cadaver; D002530:Cerebellopontine Angle / Q000601:surgery; D017626:Cochlear Nucleus / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007245:Inferior Colliculi / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged