By Ben Csiernik
Low back pain is often said to be the number one cause of years lived with disability globally (1). Now, years lived with disability is an epidemiological model that’s hard to explain, and data suggests depression is actually the leading cause of years lived with disability (2). Regardless, low back pain is a familiar condition that greatly affects quality of life globally. With low back pain’s global popularity, many people have attempted, and continue to attempt, to solve its root cause.
Along the path to solving low back pain, one common theme that has emerged is the idea that those who treat low back pain must be able to find the specific cause of pain to be able to treat it. I’ll be spending the next few paragraphs demonstrating that while hunting for the cause of specific low back pain is a worthy effort, it might not be possible, and quite frankly, might not matter.
It’s often quoted that non-specific low back pain represents around 90% of the low back pain that walks into a physical therapist or chiropractor’s office. This number gets questioned a lot, and rightfully so. So where does this approximation come from? Well, large studies precisely looking at this are really hard to do, but luckily we do have data from emergency rooms of hospitals (which tend to see scarier things than chiropractors or physios). Out of 22,655 back pain presentations to emergency department in Perth Australia, 91% of them that were determined to be of spinal origin ended up being diagnosed with non-specific low back pain (3). In 2019, Ferreira et al reported that 85% of its back pain cases of spinal origin were diagnosed as non-specific, for a total of 5461 cases (4). For further clarity, this ~90% figure comes from cases of spinal related pain and conditions like kidney disease, where back pain is a common symptom, are not counted towards the figures. So now that we have that sorted, let’s discuss some history.
If you feel the need to tell someone they’re lazy/wrong/stupid/bad at their job for using the term non-specific low back pain, then I have some reading suggestions for you. Nachemson, in his well-known paper from 1976 on the lumbar spine states “the true cause of pain remains obscure” (5). In a landmark paper by Waddell in 1987, Waddell states “In most low-back pain, however, we have neither the biomechanical nor pathologic understanding to identify any definite pathologic process nor even the anatomic source of pain” (6).
Now you might be thinking that surely we have figured some things out since the late 70’s and 80’s; turns out we haven’t. In the Lancet low back series published in 2018, the authors acknowledge that “for nearly all people with low back pain, it is not possible to identify a nociceptive cause” (7). In another Lancet paper, aptly titled “Non-specific low back pain”, the authors gently say “The most common form of low back pain is non-specific low back pain. This term is used when the pathoanatomical cause of the pain cannot be determined.” (8). While many things change over time, it seems like the idea of non-specific low back pain existing has not changed in the last 45 years.
Hypothetically, if we were to still assume at this point that non-specific low back pain wasn’t an appropriate diagnosis, which structures could we accurately determine to be the cause of all this back pain?
The Intervertebral Disc? “no investigation has accurately identified a disc problem as contributing to an individual’s pain; there is no widely accepted reference standard for discogenic pain” (7)
The Facet Joint? “clinical identification of individuals whose facet joints are contributing to their pain is not possible” (7)
The Vertebral Endplates (Modic Changes)? “identification of individuals in whom Modic changes are contributing to their pain is not possible.” (7).
Well what about motion palpation – can we feel the cause of low back pain with our hands?
No, most likely not. Most studies end with conclusions similar to “Motion palpation does not appear to be a good method to differentiate persons with or without low back pain” (9). Others say things like “manual palpatory assessment of rotation at L4-L5 in combination with ipsilateral or contralateral lateral flexion is not reliable between testers” (10). It is likely a combination that we can’t feel the cause of someone’s back pain, and if we think we do feel something, another clinician might not find the same “issue”.
Orthopedic and Other Special Tests
I would love to speak more on this, but I think we’re saving it for another time. It’s also slightly covered by the fact that I once again repeat, we cannot clinically detect that a facet joint, or a disc, or an endplate is the actual cause of low back pain. If you ask someone to do a Kemp’s test (think rotating slightly and bending backwards), and they have pain, that does not mean you know what structure is causing the pain. What this does demonstrate, is that the person is in pain when they twist and extend, that’s it.
X-rays, MRIs, and other imaging tools?
Imaging is a valid tool for when we are suspecting more sinister problems. For the sake of not writing too much, I’ll skip this discussion, but will say that when serious pathology (think cancer, fractures, etc.) are ruled out, imaging doesn’t necessarily tell us what’s causing someone’s pain. In fact, guidelines suggest we avoid imaging if there’s no high suspicion of something sinister, since it doesn’t always help show us why someone’s in pain (8).
The GOOD news
Most low back pain goes away on its own (11), and some of the best treatment for non-specific low back pain is staying active, avoiding bed rest, and trying to keep yourself moving (12). Even if we had the power to identify the specific source of most low back pain (which I hope you see now that we probably can’t), this doesn’t mean we would even change the treatment. So on that note, if you’re ready to tackle some non-specific low back pain and want to know what the best treatment is, I encourage you, as always, to go check out the NICE guidelines.
References:
1. James SL, Abate D, Abate KH, Abay SM, Abbafati C, Abbasi N, Abbastabar H, Abd-Allah F, Abdela J, Abdelalim A, Abdollahpour I. Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017. The Lancet. 2018 Nov 10;392(10159):1789-858.
2. Friedrich MJ. Depression is the leading cause of disability around the world. Jama. 2017 Apr 18;317(15):1517-.
3. Lovegrove MT, Jelinek GA, Gibson NP, Jacobs IG. Analysis of 22,655 presentations with back pain to Perth emergency departments over five years. International journal of emergency medicine. 2011 Dec;4(1):59.
4. Ferreira GE, Machado GC, Shaheed CA, Lin CW, Needs C, Edwards J, Facer R, Rogan E, Richards B, Maher CG. Management of low back pain in Australian emergency departments. BMJ quality & safety. 2019 Oct 1;28(10):826-34.
5. Nachemson AL. The lumbar spine an orthopaedic challenge. spine. 1976 Mar 1;1(1):59-71.
6. Waddell G. 1987 Volvo award in clinical sciences: a new clinical model for the treatment of low-back pain. Spine. 1987 Sep 1;12(7):632-44.
7. Hartvigsen J, Hancock MJ, Kongsted A, Louw Q, Ferreira ML, Genevay S, Hoy D, Karppinen J, Pransky G, Sieper J, Smeets RJ. What low back pain is and why we need to pay attention. The Lancet. 2018 Jun 9;391(10137):2356-67.
8. Maher C, Underwood M, Buchbinder R. Non-specific low back pain. The Lancet. 2017 Feb 18;389(10070):736-47.
9. Leboeuf-Yde C, van Dijk J, Franz C, Hustad SA, Olsen D, Pihl T, Röbech R, Vendrup SS, Bendix T, Kyvik KO. Motion palpation findings and self-reported low back pain in a population-based study sample. Journal of manipulative and physiological therapeutics. 2002 Feb 1;25(2):80-7.
10. Brismée JM, Atwood K, Fain M, Hodges J, Sperle A, Swaney M, Phelps V, Van Paridon D, Matthijs O, Sizer P. Interrater reliability of palpation of three-dimensional segmental motion of the lumbar spine. Journal of Manual & Manipulative Therapy. 2005 Oct 1;13(4):215-20.
11. Schreijenberg M, Chiarotto A, Mauff KA, Lin CW, Maher CG, Koes BW. Inferential reproduction analysis demonstrated that “paracetamol for acute low back pain” trial conclusions were reproducible. Journal of Clinical Epidemiology. 2020 May 1;121:45-54.
12 Foster NE, Anema JR, Cherkin D, Chou R, Cohen SP, Gross DP, Ferreira PH, Fritz JM, Koes BW, Peul W, Turner JA. Prevention and treatment of low back pain: evidence, challenges, and promising directions. The Lancet. 2018 Jun 9;391(10137):2368-83.