More than one aneurysm on the same artery.

More than one aneurysm on the same artery is uncommon. The authors represent 10 patients with such lesions. Three hundred and fifty-six patients were admitted to the department for treatment of cerebral aneurysm from January 1977 through April 1983. Fifty-nine patients had multiple aneurysms (17%). Out of 59 patients with multiple aneurysms, there were 10 patients with more than one aneurysm on the same artery. Thus the incidence was 2.8%. The aneurysm arose from the internal carotid artery in seven of these patients, from the middle cerebral artery in two, and from the anterior communicating artery in only one. In six cases, the larger aneurysm on the same artery proximal in three and distal in three, was found to have bled; in one, the smaller distal aneurysm had ruptured; in one, we could not identify which aneurysm had bled; and in two, another associated aneurysm had bled.