Efficacy of endovascular therapy in short-term two-stage operation for thrombosed giant cerebral aneurysm.

Background: Giant cerebral aneurysms have a high rupture rate, are often difficult to treat, and have a poor prognosis. We report two cases in which good results were achieved with a short, two-stage operation using a combination of endovascular treatment (EVT) and direct surgery. Case Description: Case 1 - A 50-year-old man had become immobile due to truncal ataxia after nausea. Magnetic resonance imaging, computed tomography (CT), and angiography revealed a giant thrombosed aneurysm of the right vertebral artery 30 mm in diameter, which compressed medulla oblongata. He underwent endovascular parent artery occlusion (PAO) followed by direct surgical thrombectomy 3 days later.The patient's outcome was modified Rankin score (mRS) 1 at 7 days after the operation and mRS 0 at 1 year. Case 2 - A 40-year-old man developed a progressive visual disturbance. CT showed a giant thrombosed aneurysm of 50 mm diameter in the C2 portion of the left internal carotid artery. A balloon test occlusion (BTO) and cerebral blood flow single-photon emission computed tomography under BTO suggested partial ischemic tolerance due to PAO. PAO followed by low flow bypass and thrombectomy of the aneurysm by direct surgery was performed on the same day.The patient's vision was improved with the outcome of mRS 1. Conclusion: EVT in a short-term two-stage operation for a thrombosed giant cerebral aneurysm is effective for the purpose of hemostasis in the thrombectomy designed to decompress the suffered brain or nerve. Complete PAO and meticulous perioperative use of antithrombotic agents are necessary to avoid perforator failure and hemorrhagic complications in this technique.