How Acute Back Pain Becomes Chronic
Chronic back pain is a very important and costly condition in advanced industrial societies which is the chief cause of limitation of physical function in younger people under 45. The definition of chronic is variable and can be taken to be a pain persisting beyond the expected healing time of the tissues which may have been damaged in the acute back pain event. This is often taken to be beyond twelve weeks as much of the soft tissue healing will have occurred at that point. Acute pain serves a biological purpose to warn us to stop doing the aggravating activity and to take care of the injured part, however chronic pain appears to have no useful function.
Back pain is a very widespread condition in the population and up to twenty percent may suffer from recurring or long term problems which are not greatly disabling. A smaller number of those people who get back pain, around five to seven percent, develop a long term pain problem which interferes with work and activity. Surgical procedures are moderately common for these problems and due to the poor blood supply of the inter-vertebral discs this may contribute to the slow resolution.
Most back pain appears to be caused by traumatic events to the back or is secondary to degenerative changes which occur in the spinal discs and joints. The connection between the spinal pathology and the pain with which a patient is suffering is not completely clear as many disc prolapses and protrusions seen on MRI scanning are not symptomatic. There may be neurological and inflammatory reasons for back pain but these factors are not clear and so the pathology of low back pain overall is not well understood.
Commonly the available diagnostic studies do not identify a particular pathology which can be connected with the back pain syndrome being investigated, at which time psychological factors are typically considered as possible causes. Psychological factors are known to be important in the development of severe pain and disability from simple low back pain but cannot be seen as causative factors as modern investigations may be insufficiently sensitive to pick up painful pathologies. Social and psychological factors should still be identified and treated as soon as they can be assessed and a management programme begun.
Heavy workers make up the greatest preponderance of claims for low back pain, with high risk categories being truck drivers, operators of heavy equipment and construction workers. The lifetime prevalence of back pain and sciatica appears to be very high in heavy workers such as those working on road construction. Sciatica is much less common than back pain (around five percent) and typically resolves without interventions, but is still an important cause of surgical management with most surgery occurring at the L4/5 level, closely followed by L5/S1. Levels of surgical management are low in the United Kingdom but can be much higher elsewhere, such as in the United States. A high percentage of back pain is caused through work or accidents, if this is the case you may want to seek some accident claims advice.
It is in western industrialised countries that the levels of disability from chronic low back pain have become very high with typical social and economic consequences. No genetic factors have been distinguished between different races to explain the variation in causative mechanisms. The split between male and female sufferers is about equal and people report low back pain mostly in middle age when the large majority have evidence of spinal degenerative changes. Sciatica, closely related to disc changes, occurs mostly in the 30s and 40s with age 42 being the average age for lumbar discectomy.
The last and more flexible part of the spine is the lumbar spine which is specialised in supporting the weight of the body above it and in transmitting it to the legs. For its size the lumbar spine is able to manage heavy loads and pass them on through the sacroiliac joints to the pelvis and the legs. There is considerable mobility in the lumbar vertebrae and they function to transmit loads by the internal bony structure of the cancellous struts forming stronger areas called trabeculae which are aligned with the lines of forces taken by the spine in activities.
The information within this article was written with the help of a Manchester Physiotherapist
Author: Jonathan Blood-Smyth