For several decades, manipulation of the cervical spine at high speed and low amplitude has been associated with rare cases of vertebrobasilar dissection and stroke. A simplified summary posits a point of view that is based on case reports and media articles describing cases of stroke after cervical manipulation. The suggested mechanism hypothesizes that the extension and rotation of the neck during cervical manipulation can damage vertebral arteries and cause an ischemic stroke. Another point of view points out that case-based evidence is circumstantial and, therefore, inadequate to establish a causal relationship.
But circumstantial evidence cannot simply be dismissed as if it didn't exist. So where does that leave us? Unlike the frequency of neck pain and chiropractic treatments, spontaneous cervical artery dissection (CAD) is rare. The annual incidence of internal carotid artery dissection has been estimated at 2.5 to 3 per 100,000 patients and that of vertebral artery dissection at 1 to 1.5 per 100,000 patients. Stroke occurs in a small proportion of people with CAD, and its true incidence is difficult to estimate.
Overall, dissection accounts for two percent of all ischemic strokes. However, vertebral artery dissection is a common cause of stroke in young and middle-aged adults. Up to 25% of stroke cases in this age group are due to vertebral artery dissection. They are most commonly reported after neck injuries or manipulations, such as car accidents, chiropractic maneuvers, sports, yoga, coughs, falls, and ceiling painting. The authors conclude that, since patients with a vertebrobasilar stroke were just as likely to visit a general practitioner as a chiropractor, these visits were likely due to pain caused by an existing dissection.
Case reports and case-control studies have suggested an association between chiropractic neck manipulation and cervical artery dissection (CAD), but a causal relationship has not been established. The search included the terms “chiropractic*”, “spinal manipulation”, “carotid artery dissection”, “vertebral artery dissection” and “stroke”. In particular, the known association of neck pain with both cervical artery dissection and chiropractic manipulation may explain the relationship between manipulation and CAD. Only human trials were included that examined patients with carotid or vertebrobasilar artery dissection and with recent chiropractic manipulations of the neck.
