**3. Historical development of surgical BR for MMD**

Yaşargil performed the first superficial-temporal artery bypass procedure for an MMD patient in 1972 [170]. In Japan, the first case was completed in 1973 by Kikuchi and Karasawa [171]. In the following years, Karasawa and colleagues in Japan refined this surgical procedure and reported their results in 1978 [123].

The first indirect MMD BR was reported by Karasawa in 1977 and was called encephalo-myo-synangiosis (EMS) [142]. Several researchers confirmed that placement of the temporalis muscle directly over the brain induced collateral vessel formation [172–174]. In 1980 Matsushima et al. introduced a new indirect BR technique, the EDAS [175]. The STA with a strip of its surrounding galea was placed directly over the brain through a linear dural incision [176]. The galea was sutured to the dural edges, and the STA left over the brain without interrupting its flow, waiting for collateral vessel formation between the dura, the galea, the STA and the brain. It became widely accepted [149, 153, 177–180]. The EMS was the ground stone for other indirect BR techniques introduced in the following years that used different donor tissues, including other scalp arteries [177], split dura [145], neck [181] or distant [182–184] muscles and the omentum [156]. Others reported using the pericranium introduced though multiple burr-holes [185]. These techniques revascularized the MCA territory but not those of the anterior and posterior cerebral arteries. In 1992, Inoue et al. [186] introduced the frontal EDAMS to selectively revascularize the anterior cerebral bed to overcome this drawback. Kinugasa et al. [187] two years later reported the ribbon EDAMS, in which a strip of galea and pericranium were placed over the frontal lobes, including the interhemispheric areas. Tenjin et al. [177] published in 1997 the occipital artery's use to revascularize the PCA territory. Ever since a combination of direct and indirect BR techniques is recommended to achieve a good collateral flow in all three brain arterial territories (anterior, middle, and posterior cerebral arteries).
