進行性に増大する後頭蓋か血栓性動脈りゅうに対する外科治療

Abstract

We report 8 patients with growing thrombosed aneurysms in the posterior fossa, all of which seriously compressed the brain stem or medulla oblongata. Angiographically, 7 of 8 cases were categorized as so-called fusiform or dolichoectatic aneurysms and 1 case was a saccular aneurysm at the basilar artery fenestration. The unilateral vertebral artery was involved in 4 cases, the basilar artery in 2 cases, and the vertebro-basilar artery in 2 cases. The 7 males and 1 female ranged in age from 38 to 64 years (mean: 48.8 years). Hypertension and hypercholesterolemia were noted in all the patients. The 3 large aneurysms at the vertebral artery were excised after occipital artery (OA)—posterior inferior cerebellar artery (PICA) anastomosis in 2 cases and endarterectomy of the contralateral vertebral artery stenosis in 1 case. The bypass functioned well and patients recovered well. The 4 giant aneurysms of the vertebral and/or basilar artery were treated by a Hunterian ligation and high-flow bypass using the radial artery graft between the extracranial vertebral artery and the posterior cerebral artery (PCA). An inverted flow direction and termination of the aneurysmal sac led to the stagnation of the blood stream in the aneurysmal dome. However thromboembolism from intra-aneurysmal clot induced serious brain stem infarction in 3 cases, and aneurysmal growth after surgery was noted in all cases. To prevent intra-aneurysmal clotting in the acute phase, strong heparinization is essential and a second step to excise the growing aneurysm in the chronic phase is also required.