Persistent hypoglossal artery: diagnostic and therapeutic considerations concerning carotid thromboendarterectomy.

Fetal anastomotic connections between the developing internal carotid and basilar arterial systems are via the three presegmental arteries: the otic artery, the hypoglossal artery, and the trigeminal artery. After formation of the posterior communicating artery from the caudal branch of the internal carotid artery, the presegmental arteries are generally obliterated. Rarely, however, these primitive carotid-basilar anastomoses will persist into adult life, and may be detected as incidental findings at the time of cerebral angiography during evaluation of the patient with suspected cerebrovascular disease. In addition, persistence of such anastomoses may result in the coexistence of anterior and posterior circulation symptoms, precipitating diagnostic confusion. Two patients with symptoms and persistent hypoglossal artery undergoing carotid thromboendarterectomy are discussed, with emphasis on clinical presentation, diagnostic criteria and intraoperative management.