Fig. 5

Neuroendoscopic video-captured images showing challeging ETV in two different cases with dolicoectatic basilar artery (DEBA). A A view via the left foramen of monro “choroid plexus (CP).” The basilar artery (BA) is seen indenting the tuber cinerium (TC), pushing it upwards and separating the mammillary bodies (MB). The upper inset showing the naked BA after ETV. The lower inset showing a thick/dense Liliequist membrane (LM) covering the perforators (white arrow) and brainstem. It has to be opened to ensure adequate CSF communication with the SAS/BC. B Upper inset showing opening LM around the DEBA with Fogarty catheter (*). Following LM fenestration, the anterior inferior cerebellar artery (AICA), brainstem (BS) and perforators are confirmed (white arrows). C, D Another case showing the basilar bifurcation (BA), posterior cerebral artery (PCA) and perforators immediately after TC opening (white arrows). The brainstem (BS) and perforators are naked and obviously seen. Notice the fenestrated LM