title: An anatomical assessment of the supracerebellar midline and paramedian approaches to the inferior colliculus for auditory midbrain implants using a neuronavigation model on cadaveric specimens.
abstract: The inferior colliculus (IC) is an alternative site for electrode placement in neural deafness due to its surgical accessibility and its well-known tonotopic stratification. In patients where tumor surgery has already occurred and the cerebellopontine angle contains scar tissue or tumor-remnants, midline and paramedian supracerebellar approaches are alternative routes. They are often avoided due to concerns regarding the venous drainage of the cerebellum, the electrode trajectory and the course of the electrode cable. We studied these surgical routes in five neuronavigated fixed cadaveric specimens. For paramedian and midline approaches, the transverse sinus was exposed 5.8mm on average. A mean of 1.6 cerebellar veins, with an average diameter of 2.0mm, draining to the tentorium were transected to reach the tentorial notch. Only 0.4 arterial branches were met. We conclude that the supracerebellar midline and paramedian approaches provide a good exposure of the IC and offer safe and viable alternative routes to the IC. Additionally, they provide a wider angle of action for optimal electrode placement.
authors.affiliation: Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str 11, 97080 Wuerzburg, Germany. Vince.g@nch.uni-wuerzburg.de
authors.forename: Giles H
authors.initials: GH
authors.lastname: Vince
authors.forename: Christian
authors.initials: C
authors.lastname: Herbold
authors.forename: Jan
authors.initials: J
authors.lastname: Coburger
authors.forename: Thomas
authors.initials: T
authors.lastname: Westermaier
authors.forename: Detlev
authors.initials: D
authors.lastname: Drenckhahn
authors.forename: Ansgar
authors.initials: A
authors.lastname: Schuetz
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Kunze
authors.forename: Laszlo
authors.initials: L
authors.lastname: Solymosi
authors.forename: Klaus
authors.initials: K
authors.lastname: Roosen
authors.forename: Cordula
authors.initials: C
authors.lastname: Matthies
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D002102:Cadaver; D002530:Cerebellopontine Angle / Q000033:anatomy & histology / Q000601:surgery; D002531:Cerebellum / Q000033:anatomy & histology / Q000098:blood supply / Q000601:surgery; D002550:Cerebral Veins / Q000033:anatomy & histology / Q000601:surgery; D003392:Cranial Sinuses / Q000033:anatomy & histology / Q000601:surgery; D003399:Craniotomy / Q000379:methods; D003638:Deafness / Q000601:surgery; D004558:Electric Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D006801:Humans; D007245:Inferior Colliculi / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008636:Mesencephalon / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D008953:Models, Anatomic; D038361:Neuronavigation / Q000379:methods*; D019635:Neurosurgical Procedures / Q000379:methods*; D019106:Postoperative Hemorrhage / Q000517:prevention & control; D019736:Prostheses and Implants