[Transdural anastomosis in moyamoya disease--vault moyamoy (author's transl)].

Transdural anastomosis in Moyamoya disease, which we have named as "Vault Moyamoya", is reported. It seems that these vault moyamoya vessels are apt to be developed at certain fixed positions; 9 definite places in children cases 6 in adults. Main feeding arteries of each vault moyamoya are dural arteries. In addition to them, the blood flow from STA and OA is found. The incidence of vault moyamoya at each position shows similar tendency both in children and adults cases. Vault moyamoya are developed more frequently around the base of the brain near the carotid fork, where occlusion exists. Less moyamoya are formed as the position is farther from the carotid fork. In children, the incidence of vault moyamoya seems to coincide with the phases of basal moyamoya. It is not clarified yet whether the adults vault moyamoya are straightly inherited from children vault moyamoya. Blood flow from vault moyamoya to the brain cannot be ignored. When STA-MCA anastomosis is applied to moyamoya cases, we had better take the degree of development and positions of vault moyamoya into consideration, because we have to cut STA and MMA in the procedure.