Pain is a complex subjective, sensory and emotional experience occurring as a result of damage or potential damage to tissue (skin, ligaments, muscles, bones). Pain is most commonly caused by a specific injury however, in some cases an injury mechanism is absent.
Types of Pain (Simplified)
There are three different types of generalised pain:
Nociceptive pain occurs when there is damage to a tissue (like burning your finger). This pain can be local or it can be referred (ie. the pain is felt away from where the tissue is damaged). An example of referred pain is, “sciatic” leg pain which is associated with tissue damage in the lower back.
Neurogenic pain occurs when the nerves behave abnormally by conducting nociceptive pain where there is no apparent tissue damage or pain source.
Psychogenic pain arises from the mind (such as the memory of a bad past experience).
Nociceptive Pain (Peripheral Pain)
Nociceptors are sensors found in the body which detect the possible threat of injury or actual injury to tissues such as bone, ligaments, skin etc. They then relay this information to the central nervous system (CNS) – spinal cord.
There are two types of nociceptive fibers, C fibers and A delta fibers which respond to different sorts of pain stimulation.
- A delta fibers carry signals from the body’s periphery (such as the fingers or feet) back to the CNS very quickly and are responsible for the acute pain experienced when a tissue has been injured.
- C fibers carry signals more slowly from the periphery to the CNS and are responsible for sub-acute/chronic pain.
When a tissue has been injured, the nociceptive fibers become sensitised. As a result, the nociceptives threshold for activation and subsequently sending pain signals back to the CNS is much lower. For example, following a bump on the head a light touch to the injured area will be painful. In the case of chronic pain, abnormal sensitisation of nociceptors contributes to why pain is easily triggered, why the pain is often disproportionate to the trigger and why pain is felt long after the initial injury stimulus has gone.
Spinal Cord and Brain Involvement
The 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”. The dorsal then determines whether the information needs to be relayed up the CNS to a higher brain centre for processing and response. Or, it may determine the response can occur locally from the dorsal horn, called a “spinal reflex response”. An example of this would be the inflammatory reponse following an injury involving muscle spasm and increased blood flow.
Chiropractic adjustments are postulated to manage spinal pain by affecting the higher brain centre, the nocipetive fibers in the periphery of your body and through the spinal cord reflex response.
Acupuncture or dry needling is another treatment intervention for managing pain. Needling affects pain at the periphery by desensitizing the nociceptive fibers so they are not stimulated as easily, while also triggering a local muscle relaxation response.
Exercise therapy and physical activity is another intervention that is beneficial in the management of pain, including pain associated with musculoskeletal conditions like osteoarthritis and low back pain.
These are all interventions The Shannon Clinic use as a part of our holistic approach to patient care.
Read more about chiropractor Dr Nicholas Shannon. [Click through to About the Shannon Clinic page]
Pain medication (analgesics) such as paracetamol (Panadol), ibuprofen (Nurofen) and diclofenac (Voltaren) work on desensitising the A delta and C fibers and hence reducing pain at the source (in the periphery). 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).
It is important to remember when taking pain medication that long term use of analgesics can have harmful side effects like gastric ulcers, renal disease and cardiovascular disease. In addition to this there is strong evidence indicating paracetamol and NSAID’s are ineffective in the treatment of low back pain.