A clinical trial was performed at my alma mater Canadian Memorial Chiropractic College (CMCC) that investigated the presence of pro-inflammatory and nociceptive (pain) proteins called chemokines in adults with low back pain and the changes of these levels in the blood following a trial of spinal manipulative therapy (SMT).
While this is early stage research, I am very excited to see investigations in the future to further our understanding of the effects of SMT. Tissue injury results in inflammatory responses that are mediated by a subfamily of chemotactic cytokines known as chemokines. These chemokines induce inflammation, affect communication between inflammatory cells and neurons, and contribute to pain transmission. They are produced on the surface of cells lining blood vessels when inflammatory cytokine activated endothelial cells are stimulated. This study looked at three different types: CCL2 (macrophage chemotactic protein), CCL3 (macrophage inflammatory protein 1α), and CCL4 (macrophage inflammatory protein 1ß).
The study had three groups of patients: 19 acute low back pain (aLBP) patients, 23 chronic low back pain (cLBP) patients, and 21 asymptomatic control patients. There were a number of exclusions such as any manual therapy in the previous 15 days, anti-inflammatory meds in the previous 48 hours, etc. Age of patients ranged from 22-60 years old: average age for aLBP was 35.5; 31.6 for cLBP; and 36.1 for asymptomatic control participants. The researchers measured patients at baseline and at the end of the study (2 weeks) with specific outcome measures. The pain patients were measured for activities of daily function using the Oswestry Disability Index (ODI) and subjective pain using visual analogue scale (VAS). All three groups blood was measured for CCL2, CCL3, and CCL4 at baseline and at the end of the study.
The LBP patients received one single adjustment (SMT) at a lumbar or SI segment on alternating days for a total of 6 adjustments over 12 days. What would have been the 7th treatment they completed the followup outcome measures along with the control group.
So what does this tell us and what should we keep in mind when interpreting this data?
The purpose of this study was to evaluate the possible effect of SMT on these chemokines and so the treatment was limited to one adjustment per treatment. That being said, in a clinical situation I will do more than one adjustment. I would be interested to see the study repeated with the frequency spread out over a longer period and treatments using multiple adjustments typical of a clinical encounter. Would more treatment result in bringing the levels down to asymptomatic levels?
I would also be interested to see these chemokine levels a few weeks or months after the treatment. Is it possible the effects were only just beginning and needed more time, or would the levels remain the same or revert back to original levels?
It would be wonderful to see an additional control group that is a pain based control group either receiving standard treatment other than SMT or maybe on a waitlist to receive SMT. This would allow us to see the levels during a natural history progression.
We also know that persistence and recurrence of low back pain is common for patients. Can this improvement without full resolution be an indicator for recurrence?
We can say with full certainty there is a correlation with the decrease in clinical outcomes (VAS and ODI) and the decrease in chemokine levels after SMT, but cannot determine if it is causation. Perhaps future studies can investigate this relationship in more detail.
Additionally we can say with full certainty there is a correlation between SMT and the decrease in proinflammatory and nociceptive chemokines, but cannot point to causation without further investigation.
Dr. Judith McCann has been living in York Region for over 15 years. After going to Queen's University in Kingston for Kinesiology, and Canadian Memorial Chiropractic College in Toronto to become a chiropractor, she decided to move back and open Haptic Health and Chiropractic in Newmarket. In February 2017, Haptic Health and Chiropractic moved 10 minutes up the road to Sharon in East Gwillimbury.