[Anatomy of the vestibulo-acoustico-facial neurovascular pedicle. Importance of therapeutic management of vestibular schwannomas].

Abstract

A perfect knowledge of the anatomy of the vestibuloacusticofacial pedicle is required to preserve hearing and facial functions during cerebellopontine angle surgery for vestibular schwannoma. A clarification of the anatomy of this pedicle, in particular of its blood supply, is presented here, based on a review of the available literature, as well as on the author's data issued from anatomical dissections on latex-injected fresh specimens, and from radiological images of the cerebellopontine angle. The blood supply to the vestibuloacusticofacial bundle arises from the meatal loop of the anterior inferior cerebellar artery most often exhibited at the porus of the internal acoustical meatus. The labyrinthine artery is particularly exposed to injury between the cochlear and facial nerves. In addition, dissection in between these two nerves is likely to sever vessels directed to these nerves even though the labyrinthine artery is not interrupted. Thus, aside from a direct injury to the labyrinth, auditory function can be impaired through two distinct ischemic lesion types. Although the facial nerve is supplied through three main arterial systems (from the labyrinthine, the middle meningeal, and the stylomastoid arteries), its labyrinthine portion is more likely to suffer from ischemic damage as it is only supplied by meatal arteries. A refinement of our anatomical knowledge of the vestibuloacusticofacial pedicle, from a functional point of view, could arise from laser Doppler measurements of labyrinthine and facial blood flow during surgery, in an attempt to improve our functional preservation rate during therapeutic procedures for vestibular schwannoma.