Postoperative Distribution of Blood Flow via the Superficial Temporal ArteryMiddle Cerebral Artery Anastomosis

Abstract

Superficial temporal artery-middle cerebral artery anastomoses were performed for the treatment of cerebral ischemic diseases due to occlusion of the internal carotid artery, and in combination with ligation of the internal carotid artery for giant aneurysms. Bypass surgery was done on the same side as the occlusion. Twenty-nine anastomoses in 27 patients underwent radiological analysis. Angiographical distribution of the intracranial blood flow through the anastomosed superficial temporal artery was analyzed from the lateral view of the postoperative films. The branches of the middle cerebral artery were divided into seven territories on the lateral projection of the angiogram according to Ring's method. In addition, visualization of the lenticulostriate artery was checked on the anteroposterior view film. The distribution area of the blood flow through the bypass was seen to be significantly wider in cases of double anastomosis than those of single anastomosis. Filling of the lenticulostriate artery was noted in cases of wider distribution. When the anastomosis was done to the suprasylvian cortical artery, the flow distribution was localized mainly in the suprasylvian frontotemporal area. On the other hand, when the infrasylvian cortical branch was revascularized, the distribution was inclined toward the infrasylvian temporal area. Thus, when one single branch of the superficial temporal artery was anastomosed to one cortical branch of the middle cerebral artery, the filling areas of the middle cerebral artery were localized on either side of the sylvian fissure, according to the site of the anastomosis. In cases where anastomoses were performed to both supra- and infrasylvian arterial branches of the middle cerebral artery, the distribution area of the bypass flow was markedly increased. It might, therefore, be better to make anastomoses to both supra- and infrasylvian cortical vessels using both branches of the superficial temporal artery, so that wider and more effective distribution of the intracranial bypass flow is obtained, and much more circulatory reserve of the brain is acquired.