Diagnostic imaging (X-ray, MRI, CT) for lower back pain, when is it necessary?

Key points:

• Less than 5% of all lower back pain (LBP) incidences are due to a specific spinal pathology identified by an image. [2]
• 95% of LBP cases can be defined as non-specific or uncomplicated, which is typically defined as having no signs of ‘red flags’ with symptoms resolved within 6 weeks of conservative management [3]
• A patient’s misinterpretation and knowledge of imaging pathologies in many situations can lead to greater fear-avoidance and a slower rate of recovery leading to chronicity.
• Seeking the guidance of a qualified Ace Certified Practitioner in the early phases of acute injury leads to greater initial health outcomes such as pain reduction and improved function.

In North America, the rate of lower back diagnostic imaging continues to be on the incline despite little evidence of improved patient outcomes. [1] Commonly, lower back pain (LBP) patients are referred to imaging centers as it is the most cost-effective approach to discovering the reason behind the pain.  For a small sub-group, this may be an effective approach, however, for the overwhelming majority, this process can potentially cause more harm than good.

To better understand why this is the case, we must investigate when a diagnostic image is deemed crucial.  Additionally, we must also review the common misconceptions of lower back images that represent the normal course of aging. 

As previously mentioned, a small subgroup in primary care; 5-10% of LBP patients, are deemed as having ‘red flag’ conditions (e.g. severe neurological deficit, spinal fractures, infection, and inflammatory disease) [2] and will undoubtedly need a diagnostic image, as an immediate cause for further investigation is most likely necessary.  However, for the remaining population of LBP patients (defined as non-specific or uncomplicated LBP), imaging will not provide a change in management and therefore nil improvements in patient health outcomes including pain, quality of life, and improved function, [2] particularly if the patient is already under-going an active rehabilitation and management process.  Furthermore, many major professional societies now recommend therapists not to order imaging for patients with back pain for less than 6 weeks if no ‘red flag’ symptoms are present as most low back pain incidences will self-resolve within this period. [4]

So, what does this mean if my lower back image report returns findings such as ‘facet degeneration’, ‘disk degeneration and height loss’, ‘disk bulge’, and ‘osteoarthritis’?

To answer this, we evaluate what is deemed a potentially harmful pathology and compare it to what is a normal non-pathological abnormality that is more related to the normal age-related changes in the spine.

The prevalence of incidental findings in asymptomatic patients

Simply put, the detection of abnormalities of the lumbar spine is not the sole determinant of pain. Many studies suggest these common abnormalities have been seen in patients without pain.  Just as our hair goes grey and our skin wrinkles, there is a linear correlation between these findings and an increase in age.  This is highlighted in a 2016 systematic review (table 2), showing the prevalence of common degenerative spine conditions on imaging in asymptomatic individuals.

Table 2: Age-specific prevalence estimates of degenerative spine imaging findings in asymptomatic patients [5]

With all this said, what is the best course of action when lower back symptoms arise?

If you have worrying signs of lower back pain, you should seek the guidance of a qualified Ace Certified Practitioner to perform both a thorough history & take a physical examination to establish a working diagnosis and to rule out any potential ‘red flags’.  Determining the presence of these more pressing indicators will dictate whether the therapist deems it necessary for you to be referred for an image.  This will shape the initial phase of your rehabilitation.  In the vast majority of LBP cases, the simple act of seeing a therapist, receiving manual therapy, and figuring out a proper course of management; including at-home exercises and a range of rehabilitation practices will lead to positive symptom improvements and faster overall health outcomes. [5]

Written by Yuma Hemphill
Osteopathic manual practitioner at Ace Sports Clinic, Toronto.

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References:

[1]. W.Flynn, T., Smith, B. and Chou, R., 2011. Appropriate Use of Diagnostic Imaging in Low Back Pain: A Reminder That Unnecessary Imaging May Do as Much Harm as Good | Journal of Orthopaedic & Sports Physical Therapy. [online] JOSPT. Available at: <https://www.jospt.org/doi/10.2519/jospt.2011.3618>.

[2].Henschke N, Maher CG, Refshauge KM, Herbert RD, Cumming RG, Bleasel J, York J, Das A, McAuley JH. Prevalence of and screening for serious spinal pathology in patients presenting to primary care settings with acute low back pain. Arthritis Rheum. 2009 Oct;60(10):3072-80. doi: 10.1002/art.24853. PMID: 19790051.

[3]. Patel ND, Broderick DF, Burns J, et al. ACR appropriateness criteria low back pain. J Am Coll Radiol. 2016 Sep;13(9):1069-1078. doi: 10.1016/j.jacr.2016.06.008.

[4]. da C Menezes Costa L, Maher CG, Hancock MJ, McAuley JH, Herbert RD, Costa LO. The prognosis of acute and persistent low-back pain: a meta-analysis. CMAJ. 2012 Aug 7;184(11):E613-24. doi: 10.1503/cmaj.111271. Epub 2012 May 14. PMID: 22586331; PMCID: PMC3414626.

[5]. Brinjikji W, Luetmer PH, Comstock B, Bresnahan BW, Chen LE, Deyo RA, Halabi S, Turner JA, Avins AL, James K, Wald JT, Kallmes DF, Jarvik JG. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. AJNR Am J Neuroradiol. 2015 Apr;36(4):811-6. doi: 10.3174/ajnr.A4173. Epub 2014 Nov 27. PMID: 25430861; PMCID: PMC4464797.