Back Pain – When To Scan?

Back Pain; When to Scan

A question I often get asked in the clinic is “should I get a scan for my back”? The simple answer – maybe. You’re probably thinking well that doesn’t really help my situation. But read further and I’ll do my best to explain.

There’s no doubt back pain is a debilitating condition, especially chronic back pain. Not only does it affect one’s physical ability – it can also be a mental burden. Most of the population at some point in their lifetime will experience some form of backpain.

What I will say about scans is that if every single person went to their GP and requested an MRI scan for their low back right now, majority of imaging would locate some sort of anomaly or change. In many studies that have used spinal imaging on patients without any back pain, there are often changes found on imaging (i.e. they had no symptoms of back pain, but radiographic imaging shows abnormalities). Don’t think this is the case? Check out the table below. For patients in their 20s such as myself, there is an estimated 37% of disc degeneration in the spine and 30% prevalence of a disc bulge in people who don’t have any symptoms of back pain! I personally think those are large percentages for a young person. Fast forward to people in their 50s – all you 50 year old’s out there, yes, you’re all still young – there is 80% disc degeneration and 60% disc bulge in people that are asymptomatic. I am not trying to scare you with these figures, but simply point out that a large proportion of people with spinal changes do NOT have symptoms of back pain.

Image link: https://www.raynersmale.com/blog/2016/6/21/spinal-degenerative-changes-are-a-natural-part-of-ageing



So what does this tell us?

There is a poor correlation between findings of scans and symptoms. The bottom line is most positive findings on scans will have little or no association with back pain and, therefore, are not overly useful in determining a relationship between symptoms or radiological changes.

So should I get a scan?

I would recommend a patient to have a scan for the following reasons:

  • No/minimal improvement in symptoms of back pain after trialling physiotherapy for 1-2 months.
  • Loss of sensation or weakness in the legs as well as abnormal reflexes.
  • Radicular symptoms that have been present some time and are severe enough to consider surgical intervention.
  • Red flag symptoms such as presence of unexplained weight loss, fever, trauma, underlying conditions such as cancer or changes to bowel or bladder function & saddle paraesthesia.

Unless the above can be justified, it is unlikely I will jump straight to imaging for the spine. Receiving imaging is not associated with improved function or pain severity. In fact, receiving scans can increase pain levels and result in catastrophising as patients are now aware of spinal abnormalities. Moreover, scans such as x-rays and CTs subject the patient to increased risks of radiation exposure. Therefore, scans may or may not be appropriate and the correct clinical judgment will be determined when an individual’s circumstances are considered.



Written by William Lewis (Physiotherapist)