When treating chronic pain as a therapist it is often apparent that the underlying cause is an injury which possibly occurred a long time ago and which the client may have forgotten about.
A good example of this is a groin strain, a common sporting injury. Strains are caused by an over stretch or contraction of a muscle, or muscle group, and can be due to sporting activities, overuse, overtraining or a physical trauma such as an accident. A groin strain typically affects one or more of the adductor muscle group, although other supporting muscles may also be affected.
Muscle strains are classified into 3 grades according to the extent of the injury and range from a Grade I, which is a mild strain where the muscle is overstretched but the person can continue to use it with mild discomfort, to a Grade III, which is a severe strain with a complete rupture of all muscle fibres or the tendon torn away from the bone. In this type of injury the person will be unable to use the muscle at all.
In all grades of muscle strain, at individual cellular (or fibre) level, the damage affects the ability of that fibre to contract and relax. Some or all of the contractile units become stuck in either a contracted or stretched position and the ability of the muscle to function is compromised.
In the acute phase of injury, which typically lasts for 72 hours, the body produces an inflammatory response causing localised heat, erythema, oedema and pain. The heat and erythema are due to increased local blood flow as leucocytes are attracted to the injury by chemicals released from the tissues. In addition, the body sends extra thrombocytes, oxygen and nutrients to the injury site to start the repair process. Lymph nodes produce additional leucocytes to help break down debris from the damaged tissue and oedema is caused by extra fluid leaking from capillaries into the tissues surrounding the injury, thus stimulating the lymphatic system to also remove debris.
Pain is an important factor in acute injury as its main function is to prevent the person from using the affected area until the tissues have been repaired. It is initially caused by stimulation of local nociceptors through inflammation and chemicals released by the tissues. Some inhibitory nerves are damaged by the injury and this, combined with an increase in sympathetic nerve activity, creates a heightened sensation of acute pain. Substance P, the neurotransmitter responsible for our perception of pain, continues to function normally, although inhibitory neurotransmitters are produced in insufficient quantities to block the increased pain messages being sent to the brain.
Pain also stimulates an autonomic nervous system (ANS) response sending the body into fight or flight mode as the sympathetic nervous system is triggered. Typically this includes increased breathing, heart rate and tightening of muscles, while other body systems such as the urinary, digestive and reproductive systems slow down. Extreme pain can also trigger involuntary responses such as sweating and nausea caused by overstimulation of the sympathetic nervous system.
Following the inflammatory response, the body starts to repair damaged tissues. Initially, vascular spasm and blood clotting through the action of thrombocytes reduce blood flow from damaged blood vessels. Collagen fibres are laid down to repair damaged tissue which results in a strong but inflexible patch of scar tissue in a process known as fibrosis.
Once the acute phase of the injury has passed, it moves into a chronic phase which can last for weeks, months or even years. The cause of chronic pain is scar tissue which creates restrictions preventing muscles from returning to normal function. The body is unable to break down the scar tissue and, instead, it adopts other coping strategies such as restricting movement of a body part or changing posture to accommodate. Affected muscles atrophy and shorten through lack of use and, in the case of a groin injury, for example, the body unconsciously starts to favour the other leg. In time, this leads to a change in gait, musculature and posture creating imbalance.
A typical sign of a chronic injury is that the affected person continues to feel pain in the area of the original injury, or even in areas distant to this caused by the formation of trigger points which refer pain along recognised nerve paths – for example, trigger points in the adductors can cause pain deep in the abdomen, pelvis, vagina, rectum and bladder; the anterior and medial thigh, knee and shin; and in the groin and around the ischial tuberosity.
Every time the person uses the injured area, they stretch and irritate the local nociceptors creating a pain response. The area becomes more sensitised to the possibility of pain which develops into a movement-pain-restriction cycle. Over time, the ANS passes the responsibility for maintaining this pain cycle to the brain, thus creating a learned pain behaviour.
Chronic pain can also overload other body systems to cause other seemingly unrelated conditions:
- long-term stimulation of the sympathetic nervous system can lead to hypertension, due to continually constricted blood vessels;
- respiratory conditions, due to constricted bronchial tubes and shallow breathing;
- irritable bowel syndrome (IBS), due to a sluggish or inactive digestive system
- depleted immunity, due to an exhausted lymphatic system.
In all cases of injury, it is therefore essential that the affected person receives hands-on therapy to address the resulting restrictions and adhesions in the tissues, thus preventing an acute injury from developing into a more serious and lasting chronic pain condition. CHW
© Amanda Oswald is an advanced massage therapist with practices in Sussex and London, Harley Street. She is also a qualified teacher, teaching advanced massage theory & practice with Jing in Brighton. amanda@paincareclinic.co.uk.
Written for Choice Health Mag
www.choicehealtmag.com
