The International Association for the Study of Pain (IASP) defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage. It goes beyond physical and physiological processes, with major contributions from pain attitudes and beliefs, personality, social factors and previous experiences.
Acute pain occurs as a protective mechanism in response to tissue trauma or surgery and usually improves with natural healing. Chronic pain is pain that persists beyond the normal tissue healing time and can often have no obvious cause. Pain is considered chronic when it remains present for a period greater than 3 months. Chronic pain may be a symptom of disease, or can be its own disease process, causing changes within the peripheral nervous system (nerve tissue outside the brain and spinal cord) and central nervous system (brain and spinal cord). These changes produce a ‘sensitive’ peripheral and central nervous system, lowering the threshold for the sensation of pain (pain signals are produced in response to a stimuli that would not have previously caused pain) and also amplifying the level of pain experienced. It is important to note that chronic pain often does not reflect actual tissue damage, and as a result, may not be seen on imaging modalities.
Key indicators of nervous system sensitisation due to pain are:
- Allodynia: production of pain in response to stimuli that normally do not cause pain (eg. brushing of a tissue over the skin causes pain)
- Hyperalgesia: increased pain response to an already painful stimulus (eg. pin prick causes increased pain)
- Cold allodynia: pain caused by a normally non-painful cold stimulus
- Cold hyperalgesia: heightened sensitivity to a painful cold stimulus
How can your physiotherapist help relieve your pain?
Physiotherapists use their knowledge of pain physiology, anatomy and musculoskeletal conditions to develop individualised treatment plans, collaborating with the patient to determine the goals for treatment. These goals often include reducing levels of pain, increasing range of motion and resumption of activities currently restricted by pain.
- Acute pain is initially managed with P.O.L.I.C.E. (Protect, Optimal Loading, Ice, Compression, Elevation) and no H.A.R.M (Heat, Alcohol, Running, Massage) principles as the initial pain response to injury is protective in nature. Early physiotherapy techniques will target tight and overactive muscles as a result of protective muscular contraction. After 24-48 hours the initial inflammatory response settles and more techniques can be introduced into treatment.
- Treatment of chronic pain does not carry these considerations due to the absence of the early inflammatory response. Therefore treatment will be selected based on the symptomatic structures and functional impairments.
Hands on treatment such as dry needling, soft/deep tissue massage, mobilisation, manipulation, neuromuscular facilitatory/inhibitory effects and taping are pain relieving techniques used commonly during treatment sessions. It is known that many of these treatment techniques act on the brain and spinal cord to stimulate production of natural opioids whilst preventing the transmission of pain signals to the brain. Local effects on joints and muscles may also occur, contributing to improvements in joint range and muscle length post treatment. Hands on treatment is always coupled with a home exercise program, as this helps to maintain the positive effects of treatment (eg. increased joint range of motion) and continues to desensitise the peripheral and central nervous system, turning down the pain volume. Most importantly, your therapist will provide you with a diagnosis and educate regarding restricted/painful structures, as well as ensuring you have an understanding of the mechanisms producing the pain.
Written by Physiotherapist Jake Pemberton.
References
http://www.painaustralia.org.au/about-pain/what-is-pain
Allchorne, A. J., Broom, D. C., & Woolf, C. J. (2005). Detection of cold pain, cold allodynia and cold hyperalgesia in freely behaving rats. Molecular pain, 1(1), 36.
http://outpatients.tas.gov.au/__data/assets/pdf_file/0003/172578/CSS_-_Physiotherapy_-_Understanding_Persistent_Pain_Booklet.pdf