[Spontaneous dissection of carotid and vertebral arteries. II. Vertebral arteries and their branches].

Dissection of the extra- and ntracranial portions of vertebral arteries, as well as basilar artery and their branches are discussed based on the up-to-date literature. Formerly, arterial dissections were found exclusively at necropsy, yet they have currently arisen to the field of interest of not only neurologists but also radiologists, neurosurgeons, and vascular surgeons. Ischemic strokes frequently result from arterial dissection, in particular subintimal dissection (most often in the extracranial portion of vertebral artery), by formation of emboli or reduced perfusion. Conversely, subadventitial and transmedial dissections produce aneurysms (most often in the intracranial portion of vertebral arteries and basilar artery) which may result in subarachnoid or intracerebral hemorrhages. The other possible mechanism of focal lesions is the compression of adjacent structures by dissected artery, most frequently by dolichoectasia of basilar artery which originates from its multiple intramural lesions. The dissections may present with cranial nerve palsies, symptoms of ischemia of cervical spine, cerebellum, and cerebral trunk, as well as occipital lobe syndromes. Arterial dissection may occur in adolescents and young adults. The clinical symptom that should be stressed is headache which precedes the occurrence of stroke for several days. The right diagnosis gives a chance for proper treatment, including operative procedures, and improved prognosis.