Pain is a complex sensation that not only involves the physical interpretation of a noxious stimulus, but also involves memories, emotions, and many neurons interacting all the way from the peripheral nervous system, up to the brain and back again. In an earlier article, I spoke at length about chronic pain and the concept central centralization modified through wide dynamic range (WDR) neurons. The WDR neuron, located in the dorsal horn of the spinal cord, acts as a communication hub for sensation. It takes inputs from many different peripheral neurons and passes the information up to the brain for processing. The brain then interprets the signal from the WDR neuron, with higher frequencies of neuronal firing being perceived as a painful stimulus. The WDR is useful for the brain as it condenses information and makes the vast number of electrical signals racing up to the brain at any given time more manageable.

The problem with this system is that sometimes signals from the body can get crossed and misinterpreted by the brain. Chronic pain often begins with an injury that creates local inflammation in an area of the body. This inflammation causes pain sensing nerves in the area to fire at high frequencies that then focus on a WDR neuron. The WDR neuron then does its job and sends the pain message up to the brain. The brain interprets the rate of the signal and informs us of the severity of the pain. Pain is meant to alert us to tissue damage, thus, when the peripheral nerves, WDR, and brain have all done their job effectively, the sensation of pain is produced in response to the tissue damage.

However, when we fast forward 3 months and that same area still hurts, the system is no longer working effectively. The problem is that the WDR neuron can become sensitized, a process called "wind-up." This means that the neuron needs less intense signals to meet the threshold for firing. This leads to faster WDR firing rates from much lower level stimuli, and these signals are still interpreted as pain by the brain. This means that even after an injury has healed, normal stimuli such as movement, pressure, or touch is now being interpreted as pain. This phenomenon is referred to as central sensitization, and is one of the primary hypotheses for the development of chronic pain. New research shows that chiropractic adjustments reduce chronic pain, in part, by disrupting central sensitization.

A new study published in the Journal, "Neuroscience", shows that chiropractic adjustments disrupt the sensitization of WDR neurons thereby reducing the pain sensation felt by patients (Randoll et al., 2017). In the study, patients receiving an adjustment had reduced pain levels from noxious stimuli designed to simulate "wind-up", while patients receiving non-specific mechanical stimulation did not have reduced pain. This study further validates an important aspect of the mechanism of pain reduction from chiropractic adjustments.

Chiropractic adjustments help people suffering from chronic pain by manipulating the tissue sending inputs to the WDR and changing the quality of those signals over time. Each visit we disrupt the chain of signals producing pain and over time the WDR calms down and becomes less responsive to painless stimuli resulting in less pain. If you or someone close to you is suffering from chronic pain, call to schedule a consultation today. Dr. Ross and his team here at Excellence in Health Chiropractic look forward to serving your healthcare needs and continuing to be a leader in quality healthcare. Take charge of your health and get back to living the life you deserve; and as always, we wish you excellence in health.

Resources:

• Randoll, C. Gagnon-Normandin, V. Tessier, J. Bois, S. Rustamov, N. O'Shaughnessy, J. Descarreaux, M. Piche, M. (2017). The mechanism of back pain relief by spinal manipulation relies on decreased temporal summation of pain. Neuroscience, 349:220-228.

Link to Abstract:

• https://www.ncbi.nlm.nih.gov/pubmed/28288900