A difficult Endoscopic Third Ventriculostomy procedure: perforation of a thick Liliequist membrane with high basilar artery location.

Endoscopic Third Ventriculostomy (ETV) is a minimally invasive and safe method used in the treatment of obstructive hydrocephalus. However, arterial bleeding episodes that arise from narrowing of the safe perforation area due to a higher location of the basilar artery (BA) may have tragic consequences. Liliequist membrane (LM) or other membranous structures located in the prepontine cistern also affect the success rates with ETV and complicate the procedure. We present herein a safe and successful perforation of the thick LM after retracting BA in a triventricular hydrocephalus case having a high BA protruding into the third ventricle. ETV is an effective and minimally invasive treatment modality in selected cases. Although some case-specific factors may affect the procedural success and feasibility, favorable and safe outcomes are certainly achievable by overcoming these obstacles with increasing experience.