Low back pain (LBP) remains the most common condition seen at physiotherapy practices. There are many factors that may contribute to LBP symptoms, and it is often difficult to identify the exact structure at fault. In fact 85% of chronic LBP disorders have no known diagnosis (O’Sullivan 2005). A diagnosis of Non-Specific Low Back Pain (NSLBP) may be given, which may further add to the frustration felt by patients.
Even when a radiological finding is present following a scan such as an MRI, it is still often difficult to ascertain the exact mechanism by which pain is felt. What is agreed upon is that LBP is often mutli-factorial in nature.
As with many other musculoskeletal injuries, acute LBP may resolve within normal tissue healing time frames of 6-12 weeks. It is when this doesn’t happen that the condition is said to be chronic, and is typically the point at which many cases will present at physiotherapy.
An on-going area of research within musculoskeletal medicine is given to subgrouping patient’s who suffer with LBP, with a view to aiding clinicians to better identify and treat this complicated problem.
O’Sullivan in 2005 attempted to sub-classify chronic LBP disorders:
- Pathoanatomical model – It makes sense that we would look to identify any abnormalities of the local structures and try to identify them as the cause of the pain. Local muscle injury, joint degeneration, disc degeneration / dehydration, and stenosis, where the gaps through which our nerves travel narrow, are common findings on MRI. If these structural changes are the cause of the symptoms they could be described as peripheral pain generators. The issue with this model is that many of these finding are commonly present when people with no LBP are scanned.
- Neurophysiological model – When someone has been in pain for any period of time, and for whatever reason, there may be changes at the spinal cord which cause normal or lightly aggravating sensory input to be perceived as painful. This is known as central sensitisation and is simply understood as being an amplification of the sensations that we feel (Wright & Zusman 2004).
- Mechanical loading model – This involves injurious loads placed upon the spine in our everyday lives. This may be due to such things as sporting activities, DIY or sustained loading postures such as sitting in a poor position at work for long periods.
- Motor control model – This may be where the support provided to the lumbar region is compromised, or for example where an activity is too intense for an individual. The body may not be strong enough, or conditioned enough to cope with the demands being placed upon it, resulting in injury. Movement and motor control impairments are also known to occur in response to pain, which may further exacerbate the symptoms (Hodges & Moseley 2003).
- Psychological model – there are many reasons that contribute to pain felt, and the everyday pressures of life may cause psychological distress that may play a role. Mal-adaptive coping strategies, negative thinking, pathological fear, abnormal anxiety and catastrophizing are among many psychological factors that may affect the way pain is generated centrally. Social factors such as family tensions and cultural beliefs may also be involved.
- Biopsychosocial model – This may be where there is a mixture of all the different models. It is now accepted that most chronic LBP sufferers will present with aspects of more than one model in their subjective history. This requires the physiotherapist to employ a multi-dimensional approach in order to understand and treat this problem (McCarthy et al 2004).
Hodges P, Moseley G. Pain and motor control of the lumbo-pelvic region: effect and possible mechanisms. Journal of Electromyo- graphy and Kinesiology 2003;13:361–70.
McCarthy C, Arnall F, Strimpakos N, Freemont A, Oldham J. The Biopsychosocial classification of non-specific low back pain: a systematic review. Physical Therapy Reviews 2004;9:17–30.
Wright A, Zusman M. Neurophysiology of pain and pain modulation. In: Modern Manual Therapy, Boyling and Jull. 3rd ed. Amsterdam: Elsevier; 2004.