Seizure following superficial temporal-middle cerebral artery anastomosis in patients with moyamoya disease: Possible contribution of postoperative cerebral hyperperfusion

Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). Seizure is known as a rare complication after revascularization for moyamoya disease, although its underlying mechanism is undetermined. We investigated the relationship between seizure attack and postoperative alteration in CBF in patients with moyamoya disease. CBF was routinely measured by N-isopropyl-p-[¹²³I] iodpamphetamine (¹²³I-IMP-SPECT) 1 and 7 days after superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis on 64 sides of the 44 consecutive patients (male:female=13: 31, 2-62 years old) with moyamoya disease. Three patients (male: female= 1: 2, 40-55 years old) suffered from seizure attack at 1 to 10 days after surgery. Two of the three patients manifested as seizures at 8-10 days after surgery and presented transient neurologic deterioration before seizure. Postoperative SPECT revealed significant increase in CBF at the sites of the anastomosis in all three patients. Postoperative magnetic resonance imaging showed no ischemic changes, and magnetic resonance angiography showed the apparently patent STA-MCA anastomosis as thick high signal intensity sign in all three patients. The anatomical location and the temporal profile of hyperperfusion were completely in accordance with the focus of seizure attack. Intensive blood pressure control and the use of antiepileptic agents were instituted. The neurologic deficits were resolved and no seizure attack recurred in three patients. Seizure following STA-MCA anastomosis can be caused by hyperperfusion in patients with moyamoya disease. When seizure attacks occur, routine CBF measurement is recommended to differentiate hyperperfusion and ischemia, since the treatments for these conditions are contradictory.