I’ve just hurt my back, do I need a scan?
So you’ve just hurt your lower back and you’re in a lot of pain. Physios refer to this as acute low back pain if it is less than 6 weeks . Getting an X-Ray or MRI may seem like a good idea. Here’s the run down on when you might need a scan and why in most cases it’s not helpful to begin with.
They don’t help you get better faster
Most patients with acute low back pain experience a marked reduction in pain and disability in the first 6 weeks . Studies have shown no clinically significant difference in patient outcomes between those who had immediate imaging of their lower back versus usual care . In fact there is evidence that if you have a scan unnecessarily your outcome may be worse for these reasons...
1) Unnecessary follow up tests for incidental findings and false alarms
Medical guidelines strongly discourage the use of MRI and X-ray in diagnosing most types of acute low back pain because they can produce false alarms . Studies have shown that imaging results correlate poorly with the pain and disability a person may be experiencing. In 2015 Brinjiki and colleagues showed a high prevalence of abnormal findings in low back MRIs in well over 3000 people without any pain or disability in ages ranging from 20 to 80 years old. They looked at low back changes such as low back disc degeneration and disc bulge. Disc bulge prevalence increased from 30% of 20 year olds to 84% of those 80 years of age. Similar results were found in over 1200 neck MRIs in subjects again with no pain or disability . To put it simply, these scan results are simply like viewing “wrinkles on the inside”. These degenerative features are likely part of the aging process, but not necessarily a reason for pain and disability .
2) Radiation exposure
Lumbar spine X-rays provide an estimated radiation dose equivalent to six months of background radiation (radiation associated with normal daily living). While the risk is considered very low, it does incur a 1 in 100 000 to 1 in 10 000 risk of fatal cancer . MRI does not require radiation exposure and provides better visualisation of soft tissue and spinal canal and is therefore preferred over CT .
3) Increased risk of surgery
For work related acute low back pain, another study found that patients who underwent MR imaging within the first month had more than an 8-fold increased risk for surgery 
The same study showed a 5-fold increase in subsequent total medical costs compared with matched control patients who did not undergo early MR imaging .
5) The labelling effect.
No evidence exists that labelling patients with low back pain with a specific anatomic diagnosis improves outcomes. Furthermore, a patient's knowledge of imaging abnormalities can actually decrease self-perception of health and may lead to fear-avoidance and catastrophising behaviours that may predispose people to chronicity . A study of 246 patients with acute low back pain divided into groups who received their MR imaging results, and those who did not. At 1 year, both groups had similar clinical outcomes but self-rated general health improved significantly more in the group that did not know the results of their MRI .
So when is imaging a good idea?
Serious and specific causes of back pain are very rare e.g. fracture, cancer, infection . Your physio will take a thorough history and conduct a physical examination looking for any “red flags” which may indicate that an MRI is necessary. Red flags include but are not limited to:
- severe or progressive neurological deficits (e.g. bowel or bladder dysfunction)
-sudden back pain with spinal tenderness (especially those with a history of osteoporosis, cancer, steroid use)
- serious trauma
- Serious underlying medical condition (cancer)
In these conditions, delayed diagnosis is associated with poorer outcomes. MRI may also be considered when a trial of conservative therapy has failed and when surgery is indicated . An X-ray of your lower back may be ordered if you have had significant trauma, are above the age of 70, are female and/or have a history of corticosteroid use.
In the future...
The role of imaging may change as technology improves and more research is conducted into the role of imaging in different types of low back pain. Current research is exploring whether MRIs may be able to detect future recurrence of low back pain. 3D MR imaging where the patient can stand rather than lie down may change the role of imaging in low back pain.
In a seminal editorial in the British Medical Journal back in 2003 Richard Heyward used the following acronyms to guide clinicians in their use of medical imaging:
“ do not B.A.R.F or V.O.M.I.T” that is do not use Brainless Application of Radiological Findings and create Victims Of Modern Imaging Technology .
Therefore your clinician should never treat the scan, and always treat the man!
When it comes to sorting your back injuries come in to see one of our highly skilled physiotherapists. Here at Thornleigh Performance Physiotherapy, we can give you an accurate diagnosis and treatment, as well as advice on the best course of action for your condition to get you back in action sooner than you could’ve imagined. We have an expertise in musculoskeletal physiotherapy and are conveniently located near Beecroft, Cherrybrook, Hornsby, Normanhurst, Pennant Hills, Wahroonga, Westleigh, West Pennant Hills, and West Pymble. So give us a call on (02) 8411 2050 to get started on a journey to a better you.
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