Extra-axial Endoscopic Third Ventriculostomy: A Novel Treatment for Managing Hydrocephalus Due to Vertebrobasilar Dolichoectasia.

Background: Vertebrobasilar dolichoectasia, a rare vascular anomaly, rarely presents with hydrocephalus. The traditional treatment for hydrocephalus is a ventriculoperitoneal shunt. Conventional endoscopic third ventriculostomy can avoid shunt-related complications but is considered risky due to the presence of the dolichoectatic vessel. A subfrontal extra-axial fenestration of the lamina terminalis can circumvent this anatomic constraint and establish cerebrospinal fluid communication between the third ventricle and subarachnoid space.

Methods: We performed an extra-axial endoscopic third ventriculostomy to manage hydrocephalus due to vertebrobasilar dolichoectasia in a 26-year-old male. The clinical description, surgical technique, outcome, and rationale are described.

Results: The patient had symptomatic improvement in his headaches and vision. There was also improvement in the postoperative ventricular indices: Evans index-19% reduction, frontal occipital horn ratio-14.1% reduction, and third ventricle index-39.5% reduction. A cine-phase magnetic resonance image showed cerebrospinal fluid flow void through the lamina terminalis fenestration, suggesting patency.

Conclusions: Extra-axial endoscopic third ventriculostomy may be a suitable treatment alternative to circumvent anatomic constraints produced by vertebrobasilar dolichoectasia in performing conventional endoscopic third ventriculostomy.