**6. Conclusions**

MMD is an uncommon cerebrovascular disorder with a higher frequency among people with Asian ancestry. Medical treatment is not helpful to stop the MMD progression and only can control minor symptoms but not ischemic nor haemorrhagic events. BR can improve brain vascularization, providing a collateral blood supply source that contains this nasty disease's progression. Direct BR is more effective in adults and adolescents than in the paediatric population. Children benefit most from indirect BR. Combined BR improves the results from direct and indirect BR and can also be used as a rescue procedure. Although controversial, many surgeons posit that asymptomatic MMD patients should be submitted to preventive BR before irreversible brain damage happens.
