Backache and its Assessment

Backache is extremely common affecting 80%-90% of adult men and women between the ages of 30 and 50 years of age. Backache is a particular challenge because it is so common, demanding of medical resources and a major cause of physical, psychological and social disability. It is important to be able to assess backache accurately, with clear aims and methods to achieve appropriate management but also to identify important pathology without wasting resources.

• Most backache (85-90%) will be so called simple low back pain (or 'mechanical low back pain') in which the symptoms by definition cannot be ascribed to a particular pathology (infection, tumour, osteoporosis, fracture, radicular syndrome, cauda equina syndrome). Simple low back ache is also called uncomplicated or non-specific low back pain and will vary with posture, activity, time and treatment.
• Radicular (or nerve root pain) will occur with low back pain. Sciatica is a lay term for pain extending into the leg (buttock, thigh, calf or heel).
• The classification into acute (less than 6 weeks), sub-acute (6-12 weeks) and chronic (>12 weeks) has been used in research but is less useful clinically because of the variable and recurrent nature of symptoms.
• Recurrent low back pain has been defined as a new episode of pain after a symptom free period of 6 months¹

Many different pathologies can cause backache or pain referred to the back. However less than 1% of people with low backache will have a serious pathology (spinal tumour, infection, ankylosing spondylitis etc). Less than 5% of people with low back pain will have true nerve root pain and in the UK very few of these are treated with surgery. The rate of surgery in the USA is five time higher than the UK and Scotland.²

• Backache is second only to the common cold as a cause of lost days at work.
• 80-90% of adults (men and women equally) will have backache at some point in their life time (most prevalent between age 30 and 50 years), and 5-13% of children between the age of 10 and 16 years of age.
• Backache was the reason for 14 million NHS GP consultations in 1994 and resulted in 7 million physical therapy sessions and 800,000 in-patient bed-days.

• To recognise serious pathology.
• To relieve pain.
• To improve function.
• To recognise and assess level of disability.
• To identify barriers to recovery.
• To prevent recurrence or persistence of symptoms.¹

This should take the form of diagnostic triage with the aims set out as above.

History

• Red flags for possible serious spinal pathology from the history are:¹
  • Age at onset less than 20 or over 50 years
  • Recent violent trauma;
  • Constant progressive, non-mechanical pain without relief from bed rest or postural modification
  • Pain unchanged despite treatment for 2-4 weeks
  • Severe morning stiffness
  • Patients unable to walk or self-care
  • Thoracic pain
  • Any past medical history of malignant tumour
  • Prolonged use of corticosteroids
  • Drug abuse, HIV, immunosuppression
  • Systemically unwell
  • Unexplained weight loss
  • Fever
  • Widespread neurological symptoms (including cauda equina syndrome)
  • Structural deformity.
• Cauda equina syndrome should be suspected if:
  • Bladder dysfunction (usually retention, sometimes overflow)
  • Sphincter disturbance
  • Saddle anaesthesia
  • Lower limb weakness
  • Gait disturbance.
  Urgent referral is mandatory.
• Identify 'yellow flag' symptoms. An attempt should be made to identify factors which predispose to chronic pain and long term disability (so called 'yellow flags'). This may, for example include inappropriate attitudes to pain and rehabilitation, inappropriate pain behaviour, work or compensation related issues, mood disturbance and emotional problems.³
• Establish the length of history, the type and the severity of pain. Is the pain acute, sub-acute or chronic? Is the pain new, recurrent or an exacerbation? Guidelines are different for acute and chronic pain.
• Differentiate between referred pain and nerve root pain. 70% of people with low back pain have pain referred to the buttock. The pain is dull and poorly localised, unlike the sharp well localised (see dermatomes) pain of nerve root pain. L5-S1 pain is common and goes to foot and toes. Often nerve root pain is exacerbated in the sitting position and ameliorated by standing or walking.¹
• Discogenic pain typically increases with sitting, flexion, coughing or sneezing.

It should be borne in mind that:

• There is little correlation between symptoms, pathology and radiological appearances when assessing acute low back pain
• Risk factors for acute low back pain, although poorly understood, are commonly reported as:heavy physical work; psychosocial factors (stress, anxiety, depression, cognitive dysfunction; job dissatisfaction; work related stress).^4-5

Examination

A brief examination for acute back pain is recommended with patient undressed, revealing spine and standing. More detailed examination with neurological examination will be necessary if the history suggests it (eg red flags).
The brief examination should incorporate: inspection, palpation and an assessment of function.
Passive straight leg raising is often used to assist diagnosis of nerve root pain but it is highly sensitive (90%) and not very specific (20%).⁶

• Diagnostic imaging only if serious pathology likely (eg red flags)⁷
• Diagnostic imaging not useful in simple low back pain and likely to waste time and resources⁸
• MRI is the most useful investigation in nerve root compression, discitis and suspected neoplastic disease⁷
• Full blood count, ESR, urine analysis if cancer, infection or inflammation suspected.⁹

Simple low back pain

• Give information, reassurance and advice
• DO NOT prescribe bed rest
• Advise to stay as active as possible
• Prescribe regular pain relief (paracetamol, non-steroidal anti-inflammatories) and consider short course of muscle relaxants
• Referral:consider physical treatments or manipulation if not resuming normal activities or multidisciplinary approaches if off work for more than 6-8 weeks (Cognitive behavioural programmes, back schools etc).^10,11

Suspected serious pathology or 'red flags'

Referral for further investigation.

High risk of chronicity, psychosocial factors

Identifying the 'yellow flags' should assist management. However evidence for interventions that work to change behaviour or prevent chronic pain and/or disability is thin.⁷ There is evidence to show that behavioural treatments may work as well as exercise therapy¹¹ and that 'back schools' for chronic and recurrent low back pain may be most effective at getting people back to work, but may not be cost-effective.¹²

Clinical Knowledge Summaries⁹ suggests referral for specialist advice:

• Immediately: cauda equina syndrome
• Urgently: serious spinal pathology suspected;progressive neurological deficit; nerve root pain not resolving after 6 weeks.
• Soon: inflammatory conditions suspected (eg ankylosing spondylitis); simple back pain not resuming normal activities after 2-3 months.

For acute low back pain:

• Pain reduces rapidly for most within 1 month
• 75% of people return to work within 1 month
• 75% of people risk recurrence within 12 months.¹³