Pain: A Simple Introduction
The entire time I was in school when we complained about the amount of information we were covering in such a short condensed period of time my department head would always say “if you think you’re learning a lot now, just wait until your first year out in the real world treating patients”. Well, I’m just a little over a year out, and I want to say that good ole Dr. Holmes was not wrong. In the year since I’ve graduated my learning has skyrocketed at a very steep rate. However, the biggest and most paradigm altering subject I’ve learned about is pain.
Pain is so common. Pain is essential to life. We have all experienced pain (except the extremely rare cases of congenital insensitivity to pain-CIP). It is a warning mechanism that something in our body is wrong, and it serves to protect us. You have damaged tissue somewhere, those PAIN messages are relayed up to your brain to let you know something is wrong, and you attempt to fix whatever is wrong. It seems so simple right?.....WRONG!
I was taught all about pain in school; both undergrad and in grad school. We learned all about the gait control theory of pain introduced by Ronal Melzak. We learned how you have free nerve endings/C-fibers/pain receptors all over your body that send pain up the spinal cord to the brain. It made so much sense at the time. This model is taught in PT school, medical school, OT school, chiropractic school, etc. The only problem is that it is completely off the mark and incredibly over simplified.
The continued work of brilliant scientists in the pain research field such as Ronald Melzak (who brought us the gate theory and has since retracted his position), Lorimer Moseley, David Butler, Adriann Louw, Louis Gifford, and many more has shown us a much more comprehensive and accurate theory of pain. Is this new theory correct? No, but it is certainly leaps and bounds ahead of the traditional view of pain that the vast majority of people subscribes to.
“Traditional therapy uses various anatomical, biomechanical or pathoanatomical (biomedical) models to help people in pain understand why they hurt. These biomedical models have proven to be very limited, especially in people suffering from chronic pain. They have an inability to explain persistent pain, spreading pain, allodynia, pain in absence of injury or disease, immune responses or stress biology.”
-Dr. Adriann Louw, PT, PhD, CSMT
In the continued exploration of pain we have discovered that pain is actually descending (generated by the brain) rather than the traditional view that it is ascending (generated by the tissues of the body). Messages are indeed sent up to the brain from the tissues, but these messages merely tell the brain about possible danger, hot, cold, movement, vibration, pressure, joint position, etc. It is then the brain’s job to evaluate this information, assimilate it with your current emotional status, memories, past experiences, and much more to decide whether or not it should generate a pain message for that area of the body in an attempt to protect you. Yes, you read that right. Pain is 100% produced by the brain based on the brain’s perception of threat. This, in and of itself, is ground breaking. Take for example the soldier with phantom limb pain after amputation from a battle injury. If the soldier has no tissue due to the removal of the limb, how can he have pain in it? It is because his brain and the areas associated with that part of the body perceive there to be a threat in that area and subsequently generate pain in an attempt to alert the soldier that there is something wrong. The inverse of this situation can be seen when the soldier is on the battlefield and is seriously wounded. He doesn’t realize until long after the fact, once he has reached safety, that he has been shot in the side. Most of you will state that he was “in shock”, but the truth of the matter is that his brain was more concerned with getting out of danger/line of fire. Therefore, his brain chose to simply ignore the information about the gunshot wound at the time because it took a back seat to survival.
This can also be very easily seen in the plethora of imaging studies that show no pain at all in people with significant tissue damage. Conversely it is not uncommon for people who have terrible pain with no tissue damage to be seen. The following is a short list of research studies that have been done that demonstrate how often tissue damage does not correlate to pain:
Understanding pain is extremely powerful. To date, at least a dozen high-quality randomized controlled trials and two systematic reviewshave shown that when people in pain are taught more about their pain, their pain decreases, function improves, catastrophization reduces and they’re more interested in movement and exercise. Additionally, it has been shown that education about pain prior to spine surgery leads to significantly superior outcomes and decreased costs to the medical system when compared with individuals who do not have an understanding of pain prior to surgery.
So why aren’t doctors, PTs, nurses, etc practicing this way? That is a great question because they should be at least attempting to do so! The Cartesian model that correlates tissue dysfunction (nociception) to pain is over 350 years old, and it’s still doctrine in medicine and various therapies. However, it is just plain false, and needs to be abandoned for a more all-encompassing approach of the biopsychosocial model of pain.
It is a very difficult task to unlearn what a clinician had drilled into their head in school and has practiced for several years. Luckily we are slowly starting to make headway with brilliant individuals such as Jason Silvernail and his “Crossing the Chasm” series, Adiann Louw with the ISPI, and Lorimer Moseley/David Butler with Explain Pain. I hope that you will join us in gaining more insight into pain. Your patients deserve it.
Disclaimer****
This blog is by no means meant to be a complete explanation of the intricacies of pain, but merely a small glimpse into the evolution of our understanding of the topic. It is ever evolving, which requires us to do the best for our patients and continue to evolve and learn right along with it.
Thank you for taking the time to read,
Jarod Hall, PT, DPT, CSCS
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