There is an anonymous quote which reads, "An archer cannot hit the bullseye if he doesn't know where the target is." In the case of some of chiropractic's detractors, that seems to have been the case when it comes to vertebral arteries. For while such critics may have appeared to have singled out the vertebral artery as an element of the circulatory system prone to destruction at the hands of a chiropractor and leading to stroke,1-3 they and too many others fail to recognize another, more widespread element in the entire circulatory system.
That element is inflammation in the chronic state. As an acute reaction, inflammation represents the proactive biological response of vascular tissue to harmful stimuli, such as pathogens, damaged cells, or irritants. Without it, wounds would never heal and infections would never clear. However, in the chronic state, a host of intermediates have been identified [VCAM-1 (adhesion molecule), cytokines (tumor necrosis factor α, interleukin-6, interleukin-18), proteases (metalloproteinase, MMP-9), platelet products (CD40L), myeloid-related protein (MRP 8/14), adipokines (adiponectin), and acute-phase reactants (C-reactive protein, plasminogen activator-1, fibrinogen)].4-5
Chronic inflammation is implicated in a wide range of disorders ranging from hay fever to periodontitis, rheumatoid arthritis,6 and especially atherosclerosis (which is the focus of this article). Ironically, there is more evidence to support the hypothesis that spinal manipulation preserves arterial integrity rather than degrading it.
In their exhaustive review of plaque and ultimately thrombus formation in the arteries, Packard and Libby describe how chemotactic cytokines (called chemokines) direct a number of processes on the way to plaque and thrombus formation:4-5
What does all this mean? In the words of Packard and Libby, "inflammation participates pivotally in all stages of atherosclerosis, from lesion initiation to progression and destabilization." But more importantly, they state that "the example of inflammation in atherosclerosis illustrates rapid translation of basic science understanding to the clinic."4
How does this relate to spinal manipulation? Consider basic animal studies from the laboratory of Xue-Jun Song at the Parker College of Chiropractic and human studies as conducted by Julita Teodorczyk-Injeyan and Stephen Injeyan at the Canadian Memorial Chiropractic College.
Song pointed out that numerous indicators of inflammation (thermal and mechanical hyperalgesia, excitability of sensory neurons as shown by electrophysiological measurements, and increased vascularization and surrounding of the dorsal root ganglia cells by glia cells) all showed that the inflammatory process produced by the injection of an inflammatory cocktail could be reversed by the application of adjustments (instrument-assisted) to the L5 or L5+L6 spinous processes of rats. The effect was segmental, as application to the L4 segment failed to reverse the indicators of inflammation.7
Turning to humans, Teodorczyk-Injeyan and Injeyan demonstrated that cavitation-producing Carver-Bridge spinal manipulations in asymptomatic subjects displayed a gradual reduction of two pro-inflammatory cytokines: tumor necrosis factor α and interleukin-1β as seen in tissue culture. The conclusion was that subjects undergoing a spinal manipulation displayed a time-dependent attenuation of inflammatory cytokines; meaning that spinal manipulation could have produced a down-regulation of inflammatory-type responses via a central, unknown mechanism.8 This work was later extended to include the reduction of another pro-inflammatory cytokine (interleukin-6) after spinal manipulation.9
Carrying these observations into symptomatic patients, the CMCC investigative team posed the following hypothesis: Is the production of inflammatory mediators and chemotactic cytokines (chemokines) altered in patients with chronic/recurrent neck pain? By collecting blood and serum samples from 27 neck pain patients and 13 asymptomatic controls, Teodorczyk-Injeyan and Injeyan demonstrated that the chemotactic cytokine tumor necrosis factor α, the monocyte chemotactic protein 1 (CCL2/MCP-1) as well as serum nitric oxide, were elevated in the neck pain patients, but not in the asymptomatic controls.10 The role of nitric oxide is significant because inflammatory and chemotactic cytokines are strong inducers of nitric oxide production; with nitric oxide playing a role in the mediation of peripheral and chronic nociception, including spinal pain.11,12
What remains to be seen is whether spinal manipulation in symptomatic humans brings about both the reduction of pain and the levels of key pro-inflammatory intermediates for clinically meaningful periods of time. First to be examined would be the cytokines: tumor necrosis factor α, interleukin-1β, and interleukin-6. But it is also very tempting to examine the levels of homocysteine, found to have a multiplicity of inflammatory and other deleterious effects on health.13
In this manner, there is the potential to come full circle in demonstrating not only that the benefits of spinal manipulation outweigh the risks, but that these benefits extend to the integrity of the artery itself. To paraphrase General Eisenhower's remarks in planning his response to the German invasion during the Battle of the Bulge in 1944-1945, there is the potential here to turn a potential defeat into a stunning victory.
References
When sports chiropractors first appeared at the Olympic Games in the 1980s, it was alongside individual athletes who had experienced the benefits of chiropractic care in their training and recovery processes at home. Fast forward to Paris 2024, where chiropractic care was available in the polyclinic for all athletes, and the attitude has now evolved to recognize that “every athlete deserves access to sports chiropractic."
It is estimated that 61% of patients with CTS avoid taking surgical options due to postoperative complications and costly surgical procedures. Chiropractic care offers a comprehensive and effective treatment for carpal tunnel syndrome, addressing the condition from multiple angles. Recent studies also have unveiled a game-changing adjunct to chiropractic treatments for CTS: nerve flossing.
Some doctors thrive in a personality-based clinic and have a loyal following no matter what services or equipment they offer, but for most chiropractic offices who are trying to grow and expand, new equipment purchases help us stay relevant and continue to service our client base in the best, most up-to-date manner possible. So, regarding equipment purchasing: should you lease, get a bank loan, or pay cash?
