Risk of Stroke

Does the claimed stroke risk from spinal manipulation add up?

A commonly cited figure claims that cervical spinal manipulation carries a stroke risk of 1 in 20,000. But when you multiply that rate by the volume of manipulations performed each year, the resulting number of manipulation-caused dissections represents an implausible portion of all cervical (carotid + vertebral) artery dissections in the entire US population. Explore the math yourself below.

Summary

At these assumptions, cervical manipulation would cause an estimated 12,480 dissections per year — 42% of the total estimated 29,370 cervical artery dissections in the US from all causes combined.

This would make manipulation a leading cause of cervical artery dissection — a proportion not supported by evidence.

Total Manipulations/yr
249.6M
Claimed Dissections
12,480
Total CeAD Cases
29,370
% of Total CeAD
42%

Modify the underlying assumptions to explore different scenarios.

Interpretation: This calculator does not attempt to determine the true risk of stroke from cervical manipulation. It demonstrates that the commonly cited "1 in 20,000" figure implies an arithmetically implausible share of all cervical artery dissections at these assumptions: manipulation alone would account for 42% of every cervical artery dissection observed in the entire US population from all causes combined — far more than the proportion actually attributable to manipulation in the epidemiological literature.

This tool is for educational purposes. It does not constitute medical advice. Adjust the assumptions to explore different scenarios.