Hydrocephalus in Vein of Galen Malformations

Vein of Galen malformation (VOGM) is a fistulous arteriovenous malformation presenting in the early childhood. Hydrocephalus with VOGM develops in one half of patients during the course of the disease. The concept of hydrodynamic disorders is the key to understand the development of hydrocephalus. VOGM results in venous hypertension that secondarily disturbs cerebrospinal fluid (CSF) absorption leading to hydrocephalus and occurs frequently in infants and young children. The medullary veins are thought to be the main pathway for absorption of CSF by the cerebrofugal gradient act as the driving force. In neonates, the cavernous sinus is poorly developed and brain does not use it for venous drainage along with poor jugular bulb maturation results in poor venous drainage reserve. The presence of high flow vascular malformation with poor venous drainage reserve leads to hydrodynamic disorder, poor CSF absorption, and hydrocephalus. Apart from this, hydrocephalus secondary to intraventricular hemorrhage and physical obstruction of the enlarged VOGM at the aqueduct has been proposed. The management strategy is to perform timely endovascular treatment to correct the hydrodynamic disorder and avoid ventricular shunting. Trans-arterial embolization is the effective way, as it decreases flow in the malformation, secondarily the venous hypertension, and thereby improving the clinical symptoms related to hydrodynamic disorder. Ventricular diversion procedure is indicated in symptomatic hydrocephalus after exhausting our effort to reduce hydrodynamic pressure by endovascular embolization.