Endoscopic Third Ventriculostomy With "Rescue" Fourth Ventriculocisternostomy: 2-Dimensional Operative Video

This case of endoscopic third ventriculostomy (ETV) and flexible endoscopy for lysis of fourth ventricle adhesions for obstructive hydrocephalus illustrates a key anatomical variant (anastomosis of posterior communicating arteries) that increases the difficulty of ETV and should be recognized preoperatively. The video further demonstrates flexible endoscopy for lysis of a fourth ventricular web and excellent third and fourth ventricular anatomy. This patient presented with normal pressure hydrocephalus-like symptoms and magnetic resonance imaging suggestive of a fourth ventricular outflow obstruction. An ETV would be an ideal intervention with a high chance of success1 and avoiding a ventriculoperitoneal shunt or a more invasive suboccipital craniectomy for fourth ventricle exploration; however, variant anatomy and resultant medialization of the bilateral posterior communicating arteries put their location directly beneath the tuber cinereum. After discussing the risks and benefits of the proposed procedure, the patient consented to proceeding with the surgery. Patient is not identifiable either by clinical vignette or through this operative video, which is entirely intraventricular. The care rendered was standard (nonexperimental). The patient did sign consent for filming and production of the educational video submitted.  Here, we present operative video from our ETV, demonstrating an inability to confirm adequate fenestration and subsequent flexible endoscopy for fourth ventriculocisternostomy.