Reoperation for moyamoya disease refractory to encephalo-duro-arterio-synangiosis

Three cases of Moyamoya disease successfully treated by reoperation are reported with special reference to the operative techniques in the second operation. These children first underwent encephalo-duro-arterio-synangiosis (EDAS). Because two of the three postoperative collateral formations through EDAS were either poor or not present at all and their symptoms remained. Encephalo-myo-synangiosis (EMS) was later added in the posterior frontal and/or parietal regions of the same side as the former EDAS. In the remaining one, the collaterals through EDAS were well formed but transient ischaemic attack (TIA) persisted in the lower limb. The collateral to the middle cerebral arterial (MCA) distribution, even though seemingly well formed, was not sufficient to obtain a complete subsidence of the symptoms. In this case encephalo-myo-arterio-synangiosis (EMAS) was later added to the antero-medial frontal region of the same side as the EDAS to form collaterals to the anterior cerebral arterial (ACA) distribution. In all three cases the angiograms after the second operation showed good formation of collaterals, and the symptoms subsided. The causes of poor collateral formation through EDAS and operative techniques for the additional operation for those cases refractory to EDAS are discussed.