Tuchin P. Chiropractic and stroke: association or causation? Int J Clin Pract. 2013;67(9):825-833. doi:10.1111/ijcp.12171.  

Concern about severe adverse neurovascular events as a result of cervical manipulation has appeared in the scientific literature since the 1960s,¹ with full-blown debate on the issue starting around 2002.² In a recent review and commentary, Australian professor Peter Tuchin discussed these concerns about spinal manipulative therapy (SMT) from the chiropractic perspective. Specifically, the author reviewed the evidence on SMT and stroke and evaluated the causal relationship according to specific criteria including strength, plausibility, and other explanations. 

First, Tuchin observed that there is not a strong association between SMT and vertebral artery dissection (VAD) and stroke. In many case reports and reviews that describe severe adverse events after SMT, the SMT was provided by either a chiropractor or a general medical practitioner. Tuchin made the argument that the neck pain leading to the chiropractor or general medical practitioner visit was probably caused by a VAD or stroke already in progress. One article³ reported, “…two of the dissection patients had VAD within seconds of receiving SMT.” Tuchin points out, “This would suggest that the VAD must have been present before the SMT, as it seems impossible for a thrombus to instantly form, dislodge, travel to the cerebral cortex to cause a stroke ‘…within seconds of receiving SMT’.” 

Second, Tuchin questioned the plausibility of the SMT-VAD association by citing a study⁴ that revealed the force exerted on the vertebral artery during SMT was not enough to produce any tearing of the vertebral artery. In the same study, the SMT forces were shown to be less than the forces used during diagnostic and range of motion testing. 

Third, Tuchin noted that the critics of SMT have not adequately reported other explanations and risk factors of stroke that could be causes of serious adverse events. For example, morbidities associated with VAD and stroke that have been cited in the literature include hypertension, hyperlipidemia, hyperhomocysteinemia, recent infection, smoking, diabetes mellitus, migraine, atrial fibrillation, obesity, cardiovascular disease, hormone replacement therapy, heavy drinking, illicit drug use, lupus anticoagulant, active malignancy, recent trauma, and genetic factors. Any of these morbidities could cause stroke and precede SMT. 

Tuchin concluded that there is a lack of compelling evidence that SMT is causally associated with stroke. Because professional liability carriers often associate osteopathic manipulative treatment with SMT, the American Osteopathic Association has addressed these concerns and determined that osteopathic manipulative treatment of the cervical spine is safe (American Osteopathic Association House of Delegates reaffirmed Resolution H-257 [A/2004—Osteopathic Manipulative Treatment of the Cervical Spine]).⁵