X-ray scans for nonspecific low back pain

Clinical question

In patients with nonspecific low back pain (LBP), do lumbar x-ray scans modify any patient outcome?

Evidence

• A meta-analysis¹ (N = 1804) examined 2 magnetic resonance imaging (MRI) and computed tomography (CT) trials and 4 x-ray trials; 0% to 44% of patients had sciatica.

  • -The trials were of relatively good quality but there was a lot of heterogeneity (except with pain).
  • -Short-term and long-term outcomes of pain, function, quality of life, mental health, and patient satisfaction did not differ significantly.

    • —Pain at 3 months approached significantly worse with x-ray scan (standard mean difference 0.19, 95% CI −0.01 to 0.39).
• A UK RCT² of 421 general practice patients with LBP for 6 weeks or longer found

  • -at 3 months statistically significant differences in

    • —the proportion of patients still in pain (74% in x-ray group vs 65%, number needed to harm [NNH] = 12),
    • —the proportion of patients requiring follow-up doctor visits (53% in x-ray group vs 30%, NNH = 5), and
    • —self-rated health status (lower in x-ray group);
  • -after 6 more months the differences were borderline but not statistically significant.
  • -However, 80% of both groups wanted x-ray scans.

    • —Those who received x-ray scans were more satisfied.
    • —X-ray scan and clinical findings were not correlated.

Context

• Early MRI and CT also do not improve outcomes.¹

• An RCT comparing MRI directly with back x-ray scans also found no difference.³

• Guidelines from Alberta,⁴ Europe,⁵ and the United States⁶ all discourage routine back x-ray scans for nonspecific LBP.

• Nonspecific LBP is LBP without recognizable or known pathology (eg, infection, tumour, osteoporosis, ankylosing spondylitis, fracture, inflammatory process, radicular syndrome, or cauda equina syndrome).^4–6

• These results and recommendations do not apply to LBP with suspected specific pathology (eg, progressive neurologic changes). Such patients require further investigation.

Bottom line

In nonspecific LBP, x-ray scans do nothing to improve outcomes and might worsen some (such as pain).

Implementation

Management of back pain is difficult and is complicated by the belief that x-ray scans are necessary to provide reassurance to the patient.⁷ As a result, x-ray scans are ordered very frequently for such patients.⁸ Because x-ray scans for nonspecific LBP increase physician workload,⁹ expose patients to very high doses of radiation, and might actually worsen short-term outcomes, many trials have been conducted to discourage this practice.¹⁰ Patients should be counseled about the benign nature of the pain and advised to remain physically active.¹¹ Educational handouts might increase patient satisfaction with back pain consultations.¹² The National Health Service has a handout that clarifies the role of x-ray scans.¹³

Tools for Practice articles in Canadian Family Physician (CFP) are adapted from articles published on the Alberta College of Family Physicians (ACFP) website, summarizing medical evidence with a focus on topical issues and practice-modifying information. The ACFP summaries and the series in CFP are coordinated by Dr G. Michael Allan, and the summaries are co-authored by at least 1 practising family physician. Feedback is welcome and can be sent to toolsforpractice@cfpc.ca. Archived articles are available on the ACFP website: www.acfp.ca.