Vestibular neurectomy in the guinea-pig: a retrosigmoid approach

The efferent cochlear system, composed of both ipsi- and contralateral bund les, runs along with the vestibular nerve and may serve as protection for t he inner ear. Sectioning of the vestibular nerve could thus create an exper imental model for further in-depth study of such a protective role. A perso nal surgical approach is described, involving a suboccipital (or retrosigmo id) route to the postero-medial aspect of the guinea-pig temporal bone, cho sen because of its use for the induction of endolymphatic hydrops in the sa me species. The crucial step in this approach is the separation of the sigm oid sinus in its entirely, through an intra-dural access with a minimal rem oval/retraction of cerebellar tissue. This did not affect either the post-o perative recovery of the animal or its hearing threshold level as assessed via auditory brainstem responses.