Case report
Endoscopy of the acoustico-facial bundle in the cerebellopontine angle – anatomic study

Introduction: In the last few years one can observe a dynamic evolution of new technologies in minimally invasive surgery. Such evolution is also present in skull base surgery. Treatment of cerebellopontine angle (CPA) lesions via the retrosigmoid keyhole approach, under endoscopic guidance, is an example of these trends. Smaller craniotomy
reduces the field of the surgeon’s vision, but the adjunctive use of 30° endoscopes can enlarge it without any
cerebellar retraction.
Aim: The aim of the study was visualization of anatomic regions which could not be seen with an operating microscope. These difficult-to-see regions are: the root entry-exit zone of the facial and acoustico-vestibular nerve (REZ), the internal auditory canal (IAC), and their relation to vessels.
Materials and methods: The study was performed on cadavers and intraoperatively. The retrosigmoid keyhole approach was used. Hopkins telescopes 0° and 30° were connected to video monitor and pictures were registered for analysis.
Results: On cadavers and intraoperatively REZ of the VIIth and VIIIth nerves were clearly seen and the IAC could be explored. Relations between vessels and nerves were demonstrated.
Conclusions: Endoscopy of the CPA is a relatively simple and helpful procedure, adjunctive to the operating microscope in the retrosigmoid keyhole approach.