Encephaloduroarteriomyosynangiosis (EDAMS) is a surgical procedure performed most commonly in children with moyamoya disease or less commonly in individuals with intracranial atherosclerotic disease (ICAD) as a form of indirect revascularization to bypass the occlusive terminal internal carotid and/or circle of Willis vessels .
It represents the combination of encephalomyosynangiosis (EMS) and encephaloduroarteriosynangiosis (EDAS) whereby superficial temporal artery branches, adjacent portions of the temporalis muscle and subjacent galeal flap, directly onto the pial surface of the brain. Revascularization occurs as a result of angiogenesis driven by local hypoperfusion and ischemia .
Encephaloduroarteriosynangiosis (EDAS) differs from EDAMS in so far as it does not include parts of the temporalis muscle but rather is limited to the superficial temporal artery, whereas encephalomyosynangiosis (EMS) only entails laying vascularized temporalis muscle onto the brain .
In EMS, EDAS and EDAMs, and unlike superficial temporal artery to middle cerebral artery (STA-MCA) bypass, no direct anastomosis is created.