Vertebral artery dissections (VAD) are a rare but important cause of ischemic stroke, especially in younger patients. Many etiologies have been identified, including motor vehicle accidents, cervical fractures, falls, physical exercise, and, as I have often discussed on this blog, cervical chiropractic manipulation. The goal of this study was to investigate the subgroup of patients who suffered a chiropractor-associated injury and determine how their prognosis compared to other-cause VAD.
The researchers, neurosurgeons from Chicago, conducted a retrospective chart review of 310 patients with vertebral artery dissections who presented at their institution between January 2004 and December 2018. Variables included demographic data, event characteristics, treatment, radiographic outcomes, and clinical outcomes measured using the modified Rankin Scale.
Overall, 34 out of our 310 patients suffered a chiropractor-associated injury. These patients tended to be younger (p = 0.01), female (p = 0.003), and have fewer comorbidities (p = 0.005) compared to patients with other-cause VADs. The characteristics of the injuries were similar, but chiropractor-associated injuries appeared to be milder at discharge and at follow-up. A higher proportion of the chiropractor-associated group had injuries in the 0-2 mRS range at discharge and at 3 months (p = 0.05, p = 0.04) and no patients suffered severe long-term neurologic consequences or death (0% vs. 9.8%, p = 0.05). However, when a multivariate binomial regression was performed, these effects dissipated and the only independent predictor of a worse injury at discharge was the presence of a cervical spine fracture (p < 0.001).
The authors concluded that chiropractor-associated injuries are similar to VADs of other causes, and apparent differences in the severity of the injury are likely due to demographic differences between the two populations.
The authors of the present paper are clear: “chiropractic manipulations are a risk factor for vertebral artery dissections.” This fact is further supported by a host of other investigations. For instance, the Canadian Stroke Consortium found that 28% of strokes following cervical artery dissection were preceded by chiropractic neck manipulation. Dziewas et al. obtained a similar rate in patients with vertebral artery dissections. Many chiropractors are in denial; however, this is merely due to their overt conflicts of interest.
My conclusions from the accumulated evidence are this:
Spinal manipulations of the upper spine should not be routinely used for any condition. Patients who nevertheless insist on having them must be made aware of the risks and give informed consent.