Bypass Surgery in Moyamoya Disease and Ischemia

The first cerebral bypass surgery was performed by Yasargil in 1967. Since that time, techniques have evolved but controversy remains regarding its indications. The current indications for cerebral revascularization are (1) flow augmentation for cerebral ischemia and Moyamoya disease/syndrome; (2) flow replacement for intracranial aneurysms and skull base tumors. Only flow augmentation will be discussed in this chapter. There has been much controversy on whether bypass should be performed for cerebral ischemia with different studies yielding conflicting results but in general, select patients with symptomatic steno-occlusive disease despite maximum medical management are thought to benefit. Bypass for moyamoya is less controversial and in general symptomatic patients are thought to benefit. This chapter reviews the history, indications, relevant anatomy, and surgical steps for bypass surgery as refined by the senior author. Surgical tips and common pitfalls are also reviewed.