Intraoperative infrared brain surface blood flow monitoring during superficial temporal artery-middle cerebral artery anastomosis in a patient with moyamoya disease: Clinical implication of the gradation value in postoperative clinical course - A case report

Background Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is a safe and effective treatment for moyamoya disease. Symptomatic cerebral hyperperfusion is a potential complication of this procedure, especially in adult cases. Accurate diagnosis of postoperative hyperperfusion is important because its treatment is contradictory to that for ischemia. Intraoper-ative techniques to detect hyperperfusion are still lacking. Methods We performed intraoperative infrared (IR) brain surface monitoring in a 36-year-old man who underwent left STA-MCA anastomosis. Findings IR monitoring not only detected the patency of bypass, as also confirmed by conventional Doppler sonog-raphy and postoperative magnetic resonance angiography, but also delineated the local brain surface hemodynamics after revascularization. Analysis of gradation value disclosed an abnormal increase in brain surface cerebral blood flow (indirectly indicated as a temperature change) after removal of the temporary clip. The patient suffered from transient right upper extremity numbness and dysarthria due to focal hyperperfusion from postoperative days2 through 6. Intensive blood pressure control completely relieved his symptoms, and he was discharged without neurologic deficit. Conclusions Intraoperative brain surface monitoring by IR imaging may be useful to predict cerebral hyperperfusion after revascularization surgery for moyamoya disease. Further evaluation with a larger number of patients is necessary to validate this technique.