First Do No Harm: a guide to choosing wisely in general practice

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Imaging in adults with acute low back pain

First Do No Harm: a guide to choosing wisely in general practice
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Last revised: 01 Nov 2022

For GPs

The routine imaging of adult patients experiencing acute low back pain.

RACGP position

  • Non-specific low back pain is a clinical diagnosis and no tests are required.1,2
  • Unnecessary diagnostic imaging causes more harm than benefit because it can result in increased costs, delays in appropriate treatment, exposure to ionising radiation and increased absence from work. It may also lead to unnecessary referrals, procedures and surgery,1 and is associated with higher rates of prolonged disability.3
  • Diagnostic imaging for acute low back pain in adults is only recommended after careful clinical assessment that results in a high suspicion that there is a serious cause.1,4,5
  • Non-specific low back pain has a good prognosis and usually improves within four weeks if the patient uses simple pain strategies, avoids bed rest and maintains their usual activities.4,6

 Traffic lights

Red

Do not take this action

  • Do not request imaging for acute low back pain unless you suspect a serious cause.1,2,5

Orange

Under specified circumstances,
take this action

  • If, after clinical assessment, you suspect cauda equina syndrome, spinal infection, an acute high-impact fracture or severe neurological deficit, you must immediately refer the patient to an emergency department for review. Do not delay this by arranging imaging.1
  • If, after clinical assessment, you suspect a serious cause, choose the imaging appropriate to the suspected pathology1,5 and discuss the costs of imaging. There is no Medicare rebate for a lumbar spine magnetic resonance imaging (MRI).

 

Green

Take this action

  • Take a careful history and perform a clinical examination.1,2,4
  • Educate the patient by explaining why you are not recommending imaging and reassure the patient by explaining the natural history of non-specific low back pain recovery.
  • Encourage the patient to maintain their usual activities.4

Unnecessary imaging causes harm, such as ionising radiation exposure, increased work absence and delay in starting appropriate treatment. Incidental findings can lead to a cascade of non-beneficial investigations, referrals, interventions and surgery, with their associated costs and harms. Incorrect interpretation of asymptomatic changes in the spine can leave the patient worried and concerned.1,4

MRI within 30 days of symptom onset when there is no clear indication associated with higher rates of prolonged disability.3

Disease burden

  • Acute low back pain, lasting four to six weeks, affects one in six Australians (16%),7 and is a frequent presentation in primary care.8

Clinical diagnosis

  • Non-specific low back pain is a clinical diagnosis and no investigations are required. In approximately 90% of people presenting with acute low back pain, a clinical diagnosis of non-specific low back pain can be made after a history and physical examination.1,2
  • Five to 10 per cent of patients presenting with low back pain will have a clinical diagnosis of radicular syndrome. Indicators suggesting radicular syndrome include predominance of leg pain, progressive muscle weakness, neurogenic claudication, tingling or numbness or abnormal findings from a neurological examination of the lower limbs.2

Assessing for a serious underlying condition

  • Serious causes are rare. Fewer than 1% of people presenting with acute low back pain will have a serious underlying condition such as spinal fracture, malignancy, infection or cauda equina syndrome.2
  • Possible indications of a spinal fracture include older age, prolonged glucocorticosteroid use, significant trauma or the presence of a contusion or abrasion.1,9
  • Possible indications of a malignant cause include a history of malignancy or unintended weight loss.1,9
  • Possible indications of a spinal infection include fever or chills, immunocompromise, pain at rest or at night, intravenous drug use, a recent injury, or a recent dental or spine procedure.1
  • Possible indications of cauda equina syndrome include new dysfunction of the bowel or bladder, perineal numbness, altered saddle sensation, or persistent or progressive lower motor neuron changes.1,10
  • Possible indications of a severe neurological deficit include motor deficits at multiple levels or progressive lower limb weakness.1 If a neurosurgical emergency is considered likely, refer the patient to an emergency department, instead of referring for imaging.

Diagnostic imaging

  • Diagnostic imaging is not indicated in the vast majority of people with acute low back pain and may cause more harm than benefit.1
  • Imaging is only indicated if there is a strong clinical suspicion of a serious underlying cause.1,4,5
  • In radicular syndrome, imaging is not routinely indicated and should only be considered in the first six weeks if the symptoms are severe and not improving and surgery is being considered.1,4,5
  • If there is a strong clinical suspicion of a spinal fracture, consider a lumbar spine X-ray or a computed tomography (CT) scan.1
  • If there is a strong clinical suspicion of malignancy, infection, cauda equina syndrome or a severe neurological deficit, consider an MRI.1,5 The clinical situation will determine the urgency. CT is an alternative if MRI is contraindicated or unavailable.5
  • If imaging is undertaken, avoid giving the patient an unhelpful diagnostic label when discussing the results.1

Prognosis

Most people, whether or not they have radiculopathy, experience substantial improvements in pain and function within four weeks.6

  • Reassure the patient that, although their pain may be severe, non-specific low back pain is almost never caused by a serious condition and that their pain will almost certainly improve within four weeks.6
  • Educate them about the importance of maintaining their usual activities, including work and physical activity.4,11
  • Advise them to not to rest in bed,4 as this can delay their recovery.
  • Encourage them to return to work.11
  • Consider advising them to use superficial heat.4
  • If analgesia is required, consider short-term non-steroidal anti-inflammatory drugs (NSAIDs).4,11
  • Although there is evidence that paracetamol is not effective in the management of non-specific low back pain, it can be offered if NSAIDs are not tolerated or are contraindicated.4
  • Opioids have a very limited role in the management of acute low back pain, as there is no evidence of their efficacy, and they are associated with significant harms.4,11
  • Make a plan with the patient that you will reassess them if significant symptoms occur within the next four to six weeks.
  • Reassess after four to six weeks.

Tools to screen for risk of chronic disability in acute low back pain

Screening questionnaire for patients with workplace injuries and to assess risk of chronicity

  1. Hall AM, Aubrey-Bassler K, Thorne B, Maher CG. Do not routinely offer imaging for uncomplicated low back pain. BMJ 2021;372:n291.
  2. Bardin LD, King P, Maher CG. Diagnostic triage for low back pain: A practical approach for primary care. Med J Aust 2017;206(6):268–73.
  3. Webster BS, Bauer AZ, Choi Y, Cifuentes M, Pransky GS. Iatrogenic consequences of early magnetic resonance imaging in acute, work-related, disabling low back pain. Spine 2013;38(22):1939–46.
  4. Makin J, Shaw K, Winzenberg T. Rapid review report: Diagnosis, investigation and management of low back pain. Hobart: KP Health and Menzies Institute for Medical Research, University of Tasmania, 2020.
  5. Hegmann KT, Travis R, Belcourt RM, et al. Diagnostic tests for low back disorders. J Occup Environ Med 2019;61(4):e155–68.
  6. Pengel LH, Herbert RD, Maher CG, Refshauge KM. Acute low back pain: Systematic review of its prognosis. BMJ 2003;327(7410):323.
  7. Australian Institute of Health and Welfare. Back problems. Canberra: AIHW, 2020 [Accessed 12 August 2022].
  8. Britt H, Miller GC, Bayram C, et al. A decade of Australian general practice activity 2006–07 to 2015–16. General practice series no. 41. Sydney: Sydney University Press, 2016. [Accessed 12 August 2022].
  9. Downie A, Williams CM, Henschke N, et al. Red flags to screen for malignancy and fracture in patients with low back pain: Systematic review. BMJ 2013;347:f7095. [Accessed 12 August 2022].
  10. Hoeritzauer I, Wood M, Copley PC, Demetriades AK, Woodfield J. What is the incidence of cauda equina syndrome? A systematic review. J Neurosurg Spine 2020;32(6):832–41. [Accessed 12 August 2022].
  11. National Institute for Health and Care Excellence. Low back pain and sciatica in over 16s: Assessment and management. London: NICE, 2016. [Accessed 12 August 2022].
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