This is a brief overview of pain and how manipulation, acupuncture and analgesic medication works.
Explaining the mechanisms behind why we experience pain is extremely complex, so here is a simplified version.
Pain is one of the most common reasons why patients seek out treatment and every person experiences pain in a different way. But what is pain? Pain is a very complex subjective, sensory and emotional experience which occurs as a result of damage to tissue (tendons, ligaments, muscles, bone etc) or the potential damage to tissue. This in simple terms means everyone has a different experience and perception of pain and it can be caused by a specific injury to tissues or there is no specific cause/tissue damage but that person still experiences pain.
Types of Pain
There are three different types of pain:
- Nociceptive Pain-occurs when there is damage to a tissue or organ (like burning your finger) and this pain can be local or it can be referred (ie. the pain is felt away from where the tissue/organ is damaged. An example of this is sciatica down the leg coming from tissue damage in the lower back).
- Neurogenic Pain-comes from abnormal activity of nerves which usually conduct nociceptive pain.
- Psychogenic Pain-arises from the mind such as, the memory of a bad past experience.
Nociceptive Pain (Peripheral Pain)
The body receives information into the central nervous system (CNS) about the possible threat of injury or injury to tissues, by nociceptive fibers which reside in the body away from the CNS.
Nociceptive fibers are broken down into two different types, which respond to different sorts of pain stimulation. These two fibers types are called C fibers and A Delta fibers.
- A Delta fibers carry signals from the periphery (ie fingers, feet) back to the CNS very quickly and are responsible for the acute pain one feels when a tissue has immediately been injured.
- C fibers carry signals more slowly from the periphery to the CNS and are responsible for the sub-acute/chronic pain one experiences.
When there has been injury to tissues these nociceptive fibers become sensitised, meaning that it takes much less stimulation for them to send pain signals back to the CNS. An example of this is following a bump on the head, light touch to the area that was hit will be painful.
Spinal Cord and Brain Involvement
All of this information carried by the A Delta and C fibers is then transmitted back into the CNS where it is processed in a part of the spinal cord called the dorsal horn. In the dorsal horn the information is processed and the spinal cord will choose to either relaying the pain information up the spinal cord to a higher brain centre for processing and response. And/or it maybe provide a “spinal reflex response” which does not require the involvement of the brain, such as, muscle guarding/spasm and increasing blood flow to the injured area (inflammatory response).
Pain medication (analgesics) such as paracetamol (Panadol), ibuprofen (Nurofen), diclofenac (Voltaren) work on desensitising the A Delta and C fibers and hence reducing pain at the source (in the periphery). While pain medications which are codeine based (Opioids) like Panadeine work by affecting how the body interprets pain in the higher brain centres (centrally, rather than peripherally).
Non-pharmacological interventions such as acupuncture and manipulation work in similar ways to non-codeine based pain medication affecting pain at the periphery rather than in the higher brain centres. They work by desensitising the nocicpetive fibers in the periphery so they are not stimulated as easily, as well as triggering a local muscle relaxation response.
It is also postulated that both manipulation and acupuncture can affect higher brain centres resulting in the release of endorphorins, which are a natural form of Opioids. Meaning acupuncture and manipulation affect pain centrally and peripherally and do so without the harmful side-effects analgesics cause like gastric ulcers, renal disease and cardiovascular disease.
This is the reason why a Chiropractor will manipulate your spine if you are experiencing pain. The adjustment (manipulation), affects the higher brain centre, and the nocicpetive fibers in the periphery of your body as well as the spinal cord reflex response.
One thing to always remember is that pain is usually the last symptom to occur and the first to disappear, just because the pain has gone doesn’t mean the underlying problem has as well. Injured tissues on average take 4-6 weeks to heal.
Understanding Pain: An Overview of Pain; Dr. Keith Charlton (June 6, 2006)
Pharmacology for Complementary Medicine Practitioners, Dr. Barbara Polus (July, 2005)