Vein of Galen Malformations

Management of children with high flow arteriovenous shunts of the brain is among the mostchallenging areas in modern medicine. Intracranial arteriovenous shunts (AVS) in childrendiffer considerably from those seen in adults, in whom brain arteriovenous malformations (AVMs) and acquired dural arteriovenous fistulae predominate. These differences are seen both in the types of lesion and in their effects. In the neonatal and infantile age groups, the most common type of AVS is the vein of Galen aneurysmal malformation (VGAM), which has a male-to-female ratio of 3:1. Progressing further into childhood, dural malformations and brain arteriovenous malformations becomemore common.1 The consequences of an AVS in the developing brain are different from those in an adult, principally because of the immature cerebral venous system: the arachnoid granulations by which cerebrospinal fluid will be returned to the cerebral venous sinuses are not fully matured until 16–18 months of age.2 In infancy, cerebrospinal fluid is reabsorbed across the ventricular ependyma and brain parenchyma into the medullary veins. The presence of a large AVS such as a VGAM may raise venous sinus pressure, which is transmitted in turn to the cortical and finally the medullary veins. This will result in water congestion of the brain parenchyma, and impaired oxygenation leading to subependymal atrophy and in severe cases a progressive “melting brain syndrome”.3 The most common presentation of VGAM results from the size of the shunt itself, imposing elevated preload on the right side of the heart leading to cardiac failure. This may progress