Revascularization and parent artery occlusion for giant internal carotid artery aneurysms in the intracavernous portion using intraoperative monitoring of cerebral hemodynamics

OBJECTIVE: Therapeutic parent artery occlusion with or without revascularization is a useful surgical technique for the management of a giant aneurysm located in the intracavernous portion of the internal carotid artery (ICA). The purpose of the present study was to determine whether intraoperative cortical blood flow (CoBF) monitoring during surgical parent artery occlusion could identify patients who required bypass with a saphenous vein graft (high flow bypass). METHODS: Eleven patients with a giant aneurysm located in the intracavernous portion of the ICA underwent superficial temporal artery-middle cerebral artery bypass. CoBF was monitored intraoperatively in all patients using a thermal diffusion flow probe. The lowest CoBF during test occlusion of the ICA under functioning superficial temporal artery-middle cerebral artery bypass was determined, and the ratio of the value to the CoBF immediately before test occlusion of the ICA was calculated in the frontal and temporal lobes. When the CoBF ratio in the frontal or temporal lobe was less than 0.9, high flow bypass grafting was elected. RESULTS: Of the eleven patients undergoing superficial temporal artery-middle cerebral artery bypass, five patients underwent concomitant high flow bypass grafting. Postoperative cerebral ischemic events did not occur in any patient over a follow-up period ranging from 3 to 60 months. Postoperative cerebral angiography showed resolution of the aneurysm and patency of the bypass in all patients. CONCLUSION: Intraoperative CoBF monitoring using a thermal diffusion flow probe during surgical parent artery occlusion for giant intracavernous carotid artery aneurysms can identify patients who require concomitant high flow bypass grafting.