The specificity of the collaterals to the brain through the study and surgical treatment of moyamoya disease.

Moyamoya disease presents clinically as chronic progressive ischemia in the young brain. The brain is surrounded by concentric collateral networks but all of these networks are not available as collaterals in the early stage of cerebral ischemia. The anatomical characteristics precluding their early use include the presence of the watery layer of subarachnoid fluid between the cortical and dural vessels and of a closed bony box intervening between the dural and scalp arterial networks. These barriers isolate the brain from the abundant blood flow of the external carotid system as if they were the moat (the subarachnoid fluid layer) and the walls (the skull) of a castle. Based on these concepts, we have developed a surgical procedure, the encephalo-duro-arterio-synangiosis to treat moyamoya disease in children. This operation surmounts the above mentioned two obstacles to collateral formation to the brain by perforating the castle wall and bridging the moat by granulation tissue, without injuring the collaterals which are already formed. This procedure was performed on 70 sides in 38 pediatric moyamoya patients. Revascularisation of the brain was obtained in 100 percent of the cases with varying improvement in the symptoms.