SIMULATION STUDY ON THERAPEUTIC VERTEBRAL ARTERY-OCCLUSION FOR VA-PICA GIANT ANEURYSM

We investigated haemodynamic effects of therapeutic vertebral artery ( VA) occlusion on giant aneurysms at the bifurcation of the VA-posterio r inferior cerebellar artery (PICA). An hydraulic model of the human v ertebro-basilar artery was manufactured from glass and silicone tubes. Glass-spheres 2.5 cm in diameter were placed at the bifurcation as mo del aneurysms with respective distances of 8.5, 7.5, 6.5 and 5.5 mm be tween the VA union and aneurysmal neck. A 40% glycerol solution was pe rfused in this system and the half-life of the dye injected into aneur ysms was regarded as an index of intra-aneurysmal stagnation. Flow con ditions in aneurysms depended on the presence or absence of the effect of contralateral VA flow as well as the PICA flow. The half-life incr eased significantly after VA occlusion proximal to the PICA when the a neurysmal neck was more than 7.5 mm away from the VA union and PICA fl ow volume was less than 12 ml min(-1). The half-life in aneurysms loca ted within 6.5 mm from the union changed little after VA occlusion reg ardless of the PICA flow volumes. The haemodynamic simulation study wo uld be helpful in speculating on the efficacy of this treatment.