Lower Back Pain (1): What the Science Says

Thanks to Herbert Trabanino MCSP MSc – Specialist musculoskeletal Physiotherapist and strength and conditioning coach – for contributing this article. Find more of Herbert’s tips and workouts at @herbert_trabanino.


A few facts & figures

If you’ve ever suffered with lower back pain, then you are in very good company.

Lower back pain (LBP) is the leading cause of years lived with disability in developed and developing countries. Approximately 80% of adults will experience at least one episode of LBP during their lifetime.

LBP is evidently a massive health and economic problem, but what exactly is going on? Why is it so common? What is the cause of LBP? How can we best treat it, and more importantly, reduce the risk of it happening in the first place?


What is LBP?


PANA Wellness

Fortunately, most cases of LBP are not serious and acute bouts usually subside after a couple of days. However, it can sometimes last up to 6 weeks or become chronic, defined as lasting more than 6 weeks.


What Causes LBP?

5-10% ~ can be attributed to a specific tissue.

1% ~ is due to a serious condition such as a fracture or in very rare cases cancer or bone infection.

  • In these specific cases, there is a very clear link between imaging findings such as MRI scans, symptoms and clinical tests. Healthcare professionals are generally very good at identifying these.

What about the other 90% of cases?

We can’t say for certain what physical structure is the source of the pain. Healthcare circles have labelled this as “non-specific lower back pain”.

To a person suffering with back pain, this label may seem unhelpful. For these individuals, the pain can feel very specific to a certain area and be aggravated by specific movements or positions, suggesting that a specific mechanical problem is occurring.

Causes of lower back pain – PANA Wellness

My MRI scan shows a disc bulge. Surely that’s the source of my pain?

Not necessarily…

We now know that imaging findings such as disc degeneration and disc bulges are extremely common in people who are completely free of back pain.

In 2015, a study looking at over 3000 MRI scans of pain-free individuals found that:

  • disc bulges were present in 40% of 30-year-olds and 77% of 70-year-olds.
  • disc degeneration was present in 52% of 30-year-olds and up to 93% of 70-year-olds.

This suggests that disc bulges and degeneration are normal age-related changes that happen to everybody and are not necessarily the cause of LBP.

We can think of these as the equivalent of the wrinkles on our skin as we get older.

Unfortunately, there is a large proportion of individuals who fall in the 90% category of “non-specific” LBP that happen to have incidental imaging findings of a disc bulge or disc degeneration. Healthcare practitioners may advise them that this is the cause of their pain.

This can potentially set off a negative cycle of fear of movement due to a belief that the spine is fragile and diseased. However, in all likelihood, the “abnormal” imaging findings are actually normal age-related changes.

This is an example of what in the medical field is known as the “biomedical model” of healthcare.


T2 and T1 weighted MRI of whole spine
Source: University of Virginia Health System. Joshua Li, MD

What is the biomedical model?

Simply put, the biomedical model implies a mechanistic cause and effect model of health and disease. It suggests that symptoms can be directly attributed to an actual physical finding.

Whilst this model has been extremely successful at advancing medical practice, when it comes to treating low back pain and chronic pain states in general it leaves a lot to be desired. In fact, there is a school of thought that chronic disabling low back pain is iatrogenic, i.e. actually caused or at least exacerbated by medical intervention.


If there is nothing specific causing my pain, then what is?

Our understanding of pain has increased exponentially over the past 20 years. We now know that in many circumstances, the level of pain we experience does not always correlate with the level of tissue damage.

Minor injuries may cause extreme pain and major injuries may cause little pain depending on the individual and the context.

In fact, we can experience pain in the absence of any tissue damage. So attempting to find an anatomical cause of most cases of LBP can be a futile exercise.


The “biopsychosocial model”

This is an alternative model of health and disease that has been gaining momentum. It offers a more complete approach in the diagnosis and management of LBP.

The biopsychosocial model integrates the input from biological, psychological, and social factors into the nervous system. Input from all three factors can sensitise the nervous system and therefore influence the perception of pain.


The Biopsychosocial Model

So, if nothing is found on a scan does that mean that the pain is all in my head?

Ultimately, the brain processes the perception of pain. The nervous system carries signals from all over the body to the spinal cord and brain where it is processed centrally. Some of these are “danger” signals that warn the brain of potential or actual tissue damage.

Whether a danger signal is perceived as pain depends on many factors which can make the nervous system more or less sensitive.

These factors include:

  • past experiences of LBP
  • negative beliefs about the state of the spine
  • levels of general physical activity
  • quality and amount of sleep
  • mental stress
  • self-efficacy (the perception that one can overcome difficult situations)

The biopsychosocial approach to LBP does not ignore the fact that tissue injury may be a driver to an individual’s pain experience. Instead, it considers the very powerful contribution of psychological and social factors.


The role of stress and sensitivity to pain.

Mental stress has a very powerful effect on the sensitivity of the nervous system.

Why?

A sustained level of mental stress increases the activity of the sympathetic nervous system (the system responsible for the “fight or flight” response). Stimulation of the sympathetic nervous system increases the levels of circulating stress hormones including cortisol and adrenaline.

This may be a good thing if you are in an actual life-threatening situation. It can prime you for action by mobilising energy stores whilst retarding other processes such as tissue repair.

Nowadays, however…

most people deal with stressors such as relationship problems, work commitments, financial demands and other social pressures.

The overall effect is that prolonged mental stress coupled with poor coping strategies changes the physiology of the body. It makes the nervous system more sensitive such that a minor niggle may cause severe pain and disability.


Summary

  • Lower back pain is a growing worldwide problem, with the majority of cases having no identifiable specific cause.
  • Disc bulges and degeneration can be normal, painless, age-related processes, but they are often labelled to be the cause of LBP.
  • We now know it is possible to experience pain in the absence of tissue damage as there are many factors (such as stress) that can influence the sensitivity of the nervous system.

-Don’t forget to read “Part 2: Treating Lower Back Pain” here


Written by Herbert Trabanino MSc

Edited and designed by Rebekah Jade BSc


References

Brinjikji, W., Luetmer, P.H., Comstock, B., Bresnahan, B.W., Chen, L.E., Deyo, R.A., Halabi, S., Turner, J.A., Avins, A.L., James, K., Wald, J.T., Kallmes, D.F and Jarvik, J.G. (2015). Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. American Journal of Neuroradiology, 36(4), 811-816.

Hartvigsen, J., Hancock, M.J., Kongsted, A., Louw, Q., Ferreira, M.L., Genevay, S., Hoy, D., Karpinnen, J., Pransky, G., Sieper, J., Smeets, R.J and Underwood, M. (2018). What low back pain is and why we need to pay attention. The Lancet, 391(10137), 2356-2367.

Hurwitz, E.L., Randhawa, K., Yu, H., Cote, P. and Haldeman, S. (2018). The global spine care initiative: a summary of the global burden of low back and neck pain studies. European Spine Journal, (suppl 6), 796-801.

Maher, C., Underwood, M. and Buchbinder, R. (2016). Non-specific low back pain. The Lancet, 389(10070), 736-747.


about the author

Herbert Trabanino MSc. MCSP.

Herbert is a chartered specialist musculoskeletal Physiotherapist, personal trainer and strength and conditioning coach. He qualified as a Physiotherapist in Australia, and obtained a Masters in Neuromusculoskeletal Physiotherapy from the University of Hertfordshire in 2016. He practices out of Spire Bushey Hospital and Harley Street Physiotherapy and specialises in the rehabilitation of musculoskeletal injuries with a special interest in low back pain and lower limb conditions. Herbert is a firm believer that exercise should be an integral part of a healthy lifestyle rather than a short-term intervention and as such promotes the integration of physical activity in all of his patients.

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