Sudden neck movement and cervical artery dissection

© 2000 Canadian Medical Association or its licensors Two recent deaths from artery dissection following neck manipulation by chiropractors have focused media and medical attention on the relation between sudden neck movement and cervical artery dissection. Although the first case of carotid artery dissection due to chiropractic neck manipulation was described over 50 years ago, the frequency of carotid and vertebral artery dissection as a cause of stroke has only been recognized in the last decade. Since then, there have been many publications and case reports on this topic. In a recent Canadian survey, dissection of the cervical arteries was one of the most common causes of stroke in patients less than 45 years of age. During the past year the Canadian Stroke Consortium, a national network of stroke physicians, has been prospectively collecting detailed information on cases of dissection of the cervical arteries. Seventy-four patients have been studied so far: their age range was 16–87 years (mean 44 years), 60% were male, and there was a predominance of vertebrobasilar artery dissections compared with carotid artery dissections (72% v. 28%). Most (81%) of the dissections were associated with sudden neck movement, ranging from therapeutic neck manipulation to a vigorous game of volleyball, but some occurred during mild exertion such as lifting a pet dog or during a bout of coughing. The vertebral artery is extremely vulnerable to torsion injury because it winds around the atlas to enter the skull: any abrupt rotation may stretch the artery and tear the delicate intima. Thrombosis formed over this vascular injury may subsequently be dislodged and may embolize to the brain. This is probably the most frequent cause of stroke in these patients and produces a characteristic angiographic appearance sometimes with “false” aneurysms (Fig. 1). Less frequently, the vessel may be occluded by a collar of hematoma forming in the vessel wall at the site of the dissection. Angiographic evidence of injury to the vertebral artery is nearly always at the C1–2 level. The carotid artery, lying freely in the soft tissues of the neck, is more mobile and less vulnerable but is tethered adjacent to C2, so that dissections may occur 1–2 cm distal to the bifurcation (Fig. 2). This is in contrast to the site of atherosclerotic lesions, which are most frequently close to the origin of the internal carotid artery. The resulting stroke follows the typical clinical pattern of its arterial territory: carotid artery dissections cause hemiparesis, hemisensory loss and other cerebral hemispheric features such as aphasia, whereas vertebrobasilar artery dissections may result in ataxia and quadriparesis. However, sudden and often severe neck or occipital pain is the hallmark of dissection (in 74% of our cases), and its onSudden neck movement and cervical artery dissection