Introduction

Mechanical back pain (aka lumbago, lower back pain) is a term used to describe musculoskeletal lower back pain. It is extremely common, with about 80% of those in Western Society experiencing it at some point in their lives. It is particularly common in those working in manual labour industries. It accounts for more days of sick leave than any other disorder.

It can be:
  • Acute – <4 weeks duration
  • Subacute – 4-8 weeks duration
  • Chronic – >12 weeks duration

Presentation

  • lower back pain
  • Worse on movement (typically bending / twisting movements) – these movements may also be a causatory factor
  • Patient generally well (no fevers or weight loss)

Pathology

  • Due to damage to the muscles / soft tissues of the lower back, as a result of posture, physical activity, lifting etc.
  • There is a cycle of muscle spasm >> pain >> spasm >> pain etc

Investigations

Are usually unnecessary unless chronic. Consider blood tests first (e.g. inflammatory markers – ankylosing spondylitis in the young,

Management

Usually self limiting. Without intervention:

  • 50% will be better after 3 weeks
  • 90% will be better after 6 weeks

Lifestyle advice

  • Avoid slouching
  • Continue normal activities to the best of your ability – this will not exacerbate the pain, and in fact, has better long-term outcomes than prescribed lateral bending exercises +/- physiotherapy.
  • Techniques for lifting, standing from sitting/lying
  • Heat – e.g. hot water bottle, heat pads do relieve pain and decrease spasm
  • Swimming – can also be useful – both due to the motor actions, and the warm water

Bed rest should be avoided after the first 48h of pain
Analgesiais useful to prevent the muscle spasm >> back pain cycle.

  • Paracetomol should be used at the start – then move up the analgesic ladder (add NSAID – ibuprofen or diclofennac if this is not effective)
  • Opioids may be required in some patients at the start, to bring pain under control

Further medications – if muscle spasm is particularly troublesome, diazepam can be used as a muscle relaxant – but be wary of the side effects (drowsiness).

  • Antidepressants decrease the level of perceived pain, but do not increase function

Physiotherapy may be useful in the acute stages to decrease muscle spasm (and subsequent pain)
Preventative measures – such as exercise (swimming, push-ups, teaching proper lifting techniques)
Additional therapies –many patients may consult a chiropractor or osteopath for manipulation / massage but this is no more effective than other methods of rehabilitation
Surgery

  • Spinal fusion – in this technique, two lumbar vertebrae are fused. It is thought that some of the pain in mechanical back injury is due to movement of the lumbar vertebrae over eachother, and that by fusing vertebrae you reduce the possibility of this occurring. However, result are, again, no better than proper conservative techniques.

Lower back pain in pregnancy

  • 50-60% of women will experience lower back pain during pregnancy
  • It typically occurs in the third trimester, as a result of the baby’s weight, and altered posture of the mother
  • It may also be possible that hormonal changes during pregnancy that increase flexibility of the pelvis, also act on ligaments in the back, increasing their elasticity, resulting in back pain.

Risk factors

For chronic lower back pain with no apparent cause
  • Smoking
  • Low socioeconomic status
  • Poor working conditions
  • Cardiorespiratroy disease
  • Large number of children (for men too!)
  • Psychological disorders (inc. anxiety and depression)
  • Long periods of sitting (e.g. at a desk) at work are NOT significant

Psychological factors – yellow flags – these are a set of risk factors for chronic back pain based on psychological beliefs. Patients who exhibit these beliefs are more likely to suffer from chronic back pain:

  • Activity, exercise and pain are harmful
  • Extended rest will help symptoms
  • Problems at work
  • Time of work / compensation due to injury
  • Overprotective family
  • Lack of social support
  • Unrealistic treatment expectations – e.g. does not attend all physio sessions, does not perform home exercises

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