Cervical manipulation and stroke risk (Cassidy 2008 and systematic reviews)

The concern that neck manipulation can tear a vertebral artery and cause a stroke (vertebral artery dissection). The large population-based study by Cassidy et al. (Spine, 2008) found that vertebrobasilar stroke was associated with visits to a chiropractor and, to a similar degree, with visits to a primary-care physician, which suggests the link reflects people with an already-developing dissection seeking care for the resulting neck pain and headache rather than manipulation causing the stroke. Later systematic reviews agree that case reports cannot establish causation. Cervical artery dissection is rare, occurring spontaneously at roughly 3 per 100,000 people per year. The practical reading: serious harm from neck manipulation is very rare and causation is unproven, but the catastrophic nature of a stroke is why neck manipulation warrants particular caution and informed consent.