Moya Moya disease is a disorder of the brain vessels at the base of the skull. These abnormal brain vessels get gradually narrowed and can cause strokes. In response to the progressive narrowing of the native arteries, new abnormal connections of arteries form to supply blood to the brain. These new arteries are fragile and are vulnerable to rupture and bleed.

Patients can present as early as the first decade of life. Adults commonly present in the third to fourth decade. Treatment options include brain surgery to either place vascularized tissue on the surface of the brain or microsurgical bypass. The former is an indirect revascularization approach where scalp vessels and muscle are laid on the surface of the highly deprived brain which can then make new healthy vascular connection that over time may be sufficient to supply adequate brain perfusion. The second option includes performing direct revascularization by sewing a scalp vessel to the vessels of the brain in a procedure called STA-MCA bypass.