The significance of the extracranial-intracranial anastomoses of carotid system in occlusion of internal carotid artery.

The existence of collateral circulation in patients with impaired intracranial circulation was studied. We analysed angiograms of 35 patients of the Neurology Clinic of Clinical Centre in Sarajevo with occlusion of internal carotid artery. In majority cases collateral circulation was not established. In patients with occlusion of internal carotid artery, extracranial-intracranial anastomoses were established in some cases, with results of surviving and patients recovery. Collateral circulation based on blood vessels which are formed in the early stages of fetal life. Some embryonal arteries undergo an involution process, while the other part of blood vessels stay unfunctional during life, until cerebrovascular disease appearence, when it comes to their activation. Establishing of the collateral circulation in post-occlusiv status depend on great number of factors: number of anastomoses, their calibre,velocity of occlusion and complete vascular status of patients.