Abstract
We have had six cases of moyamoya disease associated with aneurysms during the past 17 years. The incidence was 16%. In three cases, the aneurysms were located on moyamoya vassels or on the peripheral small arteries such as Heubner's artery, the posterior choroidal artery and the tentorial artery and were classified as a “pseudoaneurysm”. Two pseudo-aneurysms disappeared spontaneously within three months after onset. Therefore, pseudo-aneurysms required no direct surgery, though STA-MCA anastomosis had a preventative effect on rebleeding. Conversely, the remaining three cases were classified as saccular aneurysms, located on the circle of Willis such as the carotid fork, anterior communicating artery or basilar bifurcation. Of these three cases, only one, the basilar bifurcation aneurysm, rebled two years later, causing death due to vasospasm, while the other two aneurysms, on the carotid artery system, did not rebleed and showed gradual reduction in size. Based on our experience, it was suggested that aneurysms on the vertebrobasilar system should have direct surgery because of a high probability of rupture, whereas aneurysms on the carotid artery system, showing better prognosis, can be treated conservatively with careful follow-up angiography.
