Neurochirurgie
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The angiographic and/or anatomic study of a series of 30 cases of Vein of Galen aneurysm (which is defined as an arterio-venous fistula within the wall of the vein of Galen itself, therefore as a purely extra cerebral lesion) permits the analysis of the afferent arteries, of the efferent veins, and of the aneurysmal sac itself. The examination of the afferent arteries confirms the data from the literature, indicating that most often it consists of the abnormal hypertrophy of otherwise normally organized arteries, including the dural arteries. In particular, the involvement of distal subcallosal branches of the anterior cerebral arteries as well as the arterio-arterial maze extending above the collicular plate, fit well the normal anatomy. ⋯ Unfortunately, no clue was found to orient to a specific cause for the anomaly. The frequently observed venous occlusions are actually not seen in neonates but rather in older children. This, and the fact that spontaneous thromboses within the malformative veins have been observed in vivo, make likely the conclusion that venous occlusions are a secondary phenomenon only.