European Spine Journal

July 2018; Vol. 27; No. 7; pp. 1526–1537

Cesar A. Hincapié, George A. Tomlinson, Pierre Côté, Y. Raja Rampersaud, Alejandro R. Jadad, J. David Cassidy:


The association between chiropractic care and acute lumbar disc herniation has been a topic of significant interest and debate in the healthcare community. A recent groundbreaking epidemiological study aimed to investigate this association, comparing it with the relationship between primary care physician (PCP) care and acute lumbar disc herniation with early surgical intervention. The study, encompassing a vast population over an 11-year period, is the first of its kind, providing valuable insights into the risks associated with chiropractic treatment in this context.

The Scope of the Study:

This pioneering study utilized a population of more than 100 million person-years, including the entire population registered in Ontario’s provincial healthcare system. Covering an extensive 11-year period, the research aimed to identify cases of early surgically managed acute lumbar disc herniation, as well as visits to chiropractors and PCPs.

Addressing Protopathic Bias:

The study acknowledged the concept of protopathic bias, a potential source of bias when a treatment for initial symptoms appears to cause or accelerate a deteriorating outcome. This bias arises when there is a lag time between the onset of symptoms, the initiation of treatment, and the actual diagnosis. To counter this, the researchers implemented a robust methodology, considering the natural progression of the disease and distinguishing it from any potential impact of the treatment.

Comparison with Previous Research:

In drawing parallels with a previous study examining the association between chiropractic care and vertebrobasilar stroke, the researchers found similar associations between both chiropractic care and PCP care. Importantly, there was no evidence of excess risk for vertebrobasilar stroke associated with chiropractic care compared to primary medical care.

Key Findings and Implications:

  • Back pain, a prevalent issue managed by physicians, chiropractors, and physical therapists, affects a substantial percentage of the population globally.
  • Chiropractic care, often sought for low back pain, was investigated for its potential link to an increased risk of acute lumbar disc herniation.
  • The study suggested a positive safety profile for chiropractic care concerning the baseline risk represented by PCP care, providing reassurance regarding its safety in this context.
  • Protopathic bias was considered, emphasizing the importance of understanding the timing of symptoms, treatment initiation, and diagnosis to avoid misattributing causality.
  • Patients with prodromal back pain sought healthcare from both chiropractors and PCPs before the full clinical expression of acute lumbar disc herniation, highlighting the complex nature of symptom progression.


This groundbreaking epidemiological study contributes significantly to our understanding of the association between chiropractic care and acute lumbar disc herniation. By considering a vast population over an extended period, the researchers offer valuable insights that enhance the safety profile of chiropractic care in comparison to PCP care. The findings emphasize the need for a nuanced understanding of symptom progression and healthcare-seeking behavior, paving the way for informed decision-making in the management of acute lumbar disc herniation.