The Development of Chronic Back Pain

For people of forty-five or younger low back pain syndromes are the major cause of activity limitation in the industrialised societies of the west. Defining what a chronic syndrome has been agreed that any condition lasting longer than the expected time of healing of the soft tissues could be classed as chronic, a period of approximately three months. The soft tissues of the body should heal in this time and pain has a useful survival function for us in these cases, making us remove the injuring forces and look after the damaged part as it heals. There appears to be no useful biological function for the chronic pain syndromes.

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.

Injuries occurring to the spine and the onset of degenerative changes in the joints and the discs may explain many of the back pain problems which arise but there is a poor relationship between the amount of pathological changes in the spine and the level of pain suffered by a patient. MRI scanning reveals many disc changes such as protrusions or prolapses in individuals who are not complaining of significant pain. The causes are not well understood but may include inflammatory and neurological influences.

If imaging and other diagnostic studies do not reveal a plausible pathological reason for a person’s back pain then it is very easy to question whether psychological factors are responsible. Although psychological factors combine in a complex way in the progress from acute back pain towards a disabling condition there is no good evidence that psychological factors can produce pain. The cause of the pain may just not be amenable to the forms of investigation now prevalent. Once the condition is present or developing however, and arguably even in the acute stage, it is vital to identify and deal with all the non-physical factors to attain the best outcome.

The highest levels of low back pain claims occur in construction, heavy equipment operators and lorry drivers being high risk groups. In heavy workers such as in the construction of roads the levels of back pain and sciatica throughout their working lives appears to be very high. True sciatica occurs in only five percent of back pain cases and is a common reason for surgical intervention with L4/5 being the most commonly affected level, followed closely by L5/S1. Surgery for sciatica is rarely performed in the United Kingdom, with much elevated rates in other countries as in the US.

The levels of chronic disability from low back pain problems has reached crisis proportions predominantly in western and industrial countries, causing both economic and social side effects. The underlying degenerative changes in the spine have not been shown to have any different genetic origin between races. Back pain problems present in equal numbers in both women and men with middle age being the prime time for these complaints to surface due to the likely presence of spinal changes by this time. Sciatica mostly occurs in a person’s forties or thirties and the average age for operative disc surgery is 42.

The lumbar spine is the final flexible part of the spinal column whose function is to support the upper body and abdomen over the legs as we stand. The lumbar spine is designed to manage heavy loads compared to its size and transmits the weight via the sacroiliac joints to the sacrum and so on to the legs. The lumbar vertebrae have significant mobility and are designed to transmit load along the spine. The internal bone struts of cancellous bone form strengthened areas along the lines of typical stresses and the vertebral bodies get bigger as they go down due to the increased loads above.