Intraoperative Superficial Temporal Artery-middle Cerebral Artery Bypass Failure during Combined Bypass Surgery in Children with Moyamoya Disease.

Pediatric patients with moyamoya disease frequently show rapid progression with a high risk of stroke. Indirect revascularization is widely accepted as a surgical treatment for pediatric moyamoya disease, but it does not augment cerebral blood flow immediately, which leaves patients at risk for stroke peri-operatively. This delay in flow augmentation may make adding direct bypass the better option. This study documents our cases of direct bypass failure that underwent indirect bypass supplemented with superficial temporal artery-middle cerebral artery bypass to evaluate the adverse effects of direct bypass failure. A retrospective review of all surgeries for pediatric moyamoya disease after introducing intraoperative indocyanine green videoangiography to confirm direct bypass patency identified 78 surgical hemispheres. Direct bypass failure was defined as failure to confirm blood flow from the superficial temporal artery to the middle cerebral artery on indocyanine green videoangiography. The occurrence of ischemic complications was evaluated by magnetic resonance imaging. During the period, postoperative ischemic complications were seen in 3 surgical hemispheres (3.8%) and one contralateral hemisphere (1.3%). One case in which hyperventilation was difficult to control postoperatively developed extensive cerebral infarction. Direct bypass failure was seen in 3 patients (3.8%), none of whom had additional cerebral infarction on magnetic resonance imaging. The results of this study indicate that failure of direct bypass surgery does not necessarily lead to cerebral infarction. Based on these results, surgeons can safely attempt to add a direct bypass to an indirect bypass, with special attention to perioperative patient management.