Moyamoya disease is one of several conditions generally described as "cerebrovascular insufficiency". Moyamoya disease affects both adults and children. It is characterized by progressive narrowing of the internal carotid artery as it enters the base of the brain. This narrowing results in decreased blood flow to the brain. The decreased blood flow leads to strokes or transient ischemic attacks (TIA’s or "mini-strokes"). Typically medical treatment of this condition with drugs is not effective. At Johns Hopkins, patients with moyamoya disease and other cerebrovascular insufficiency conditions undergo an extensive evaluation by a team of neurosurgeons, neurologists, and neuroradiologis. If the problem cannot be treated with medicine then surgery is considered. During surgery, new blood flow to the brain can be accomplished using one of three techniques. We typically use all three techniques during one surgery. The first surgical technique is the microsurgical extracranial-to-intracranial (EC-IC) bypass surgery. In general this is done using the superficial temporal artery (STA) which is anastomosed to the middle cerebral artery (MCA). This is referred to as an STA-MCA bypass, which is defined as a “direct” revascularization technique. When a direct revascularization procedure such as the STA-MCA bypass cannot be carried out, we perform two "indirect" bypass procedures. These consist of (1) transferring an arteriovenous pedicle of the superficial temporal artery to the surface of the brain and (2) bringing the temporalis muscle in contact with the brain. The first procedure is referred to as the encephaloduroarteriosynangiosis (EDAS) and the second as the encephaloduromyosysnangiosis (EDMS). Typically these two are done together and then the procedure is described as the encephaloduroarteriomyosynangiosis (EDAMS). With time new vessels grow into the brain from the arteriovenous STA pedicle or the temporalis muscle. Johns Hopkins is one of the few centers where these procedures are performed. The results are typically outstanding.