Perioperative care of the pediatric patient for pial synangiosis surgery

Moyamoya disease (MMD) is a cerebrovascular occlusive disorder which causes recurrent strokes and transient ischemic attacks in children. The arteriopathy of MMD targets the internal carotid arteries (ICA) and their branches resulting in ischemia of the ICA circulation. Small perforator branches of the ICA dilate to provide collateral perfusion to ischemic areas. This small vessel dilatation creates the characteristic angiographic appearance that gives the disease its name ("moyamoya" after the Japanese expression for "something hazy just like a puff of cigarette smoke drifting in the air"). Best medical management involves the prevention of thromboembolic events with antiplatelet agents, maintaining adequate hydration, and avoidance of hyperventilation which can contribute to cerebral vasoconstriction. Presently there are no definitive medical options to halt or correct the process of MMD. Surgical procedures include both direct and indirect revascularization. Direct revascularization involves anastomosis of a branch of the external carotid artery to a branch of the internal carotid artery (STA-MCA bipass). However, indirect procedures are often chosen in the pediatric population due to the technical difficulty of direct procedures related to small diameter blood vessels. Indirect procedures rely on neovascularization, so the increase in cerebral blood flow is delayed beyond the immediate postoperative period. One such indirect procedure is pial synangiosis, which involves suturing the adventitia of the superficial temporal artery to the pial surface of the cerebral cortex after opening of the arachnoid. The authors present two pediatric patients who required anesthetic care for pial synangiosis surgery. The perioperative care of such patients is reviewed and suggestions presented for the intraoperative anesthetic management.