[Chronic subdural hematoma developing after EMS for moyamoya disease].

A case of chronic subdural hematoma following EMS (Encephalo-Myo-Synangiosis) for moyamoya disease was presented. Two and a half year-old girl was admitted to our division because of right hemiparesis. Left carotid angiography revealed a very narrow left carotid bifurcation and small moyamoya vessels. EMS was performed on the left side and a right hemiparesis was improved. But she developed a headache and vomiting one month after the operation. CT scan and angiogram showed a chronic subdural hematoma on the left side. A hematoma weighing approximately 30 g was evacuated. We reviewed a similar case of 5-year-old boy in the literature and discussed the mechanism accounting for formation of the chronic subdural hematoma following EMS.