SHOULD YOU HAVE A SCAN IF YOU HAVE LOWER BACK PAIN?
Lower back pain is the most common presenting complaint to me in the clinic on a daily basis. In fact lower back pain is estimated to effect 85% of the Australian population at some stage during their lives. Now whilst 70-80% of sufferers will recover from an acute episode of lower back pain within a 3 month period, 20-30% of sufferers will suffer from persisting pain and loss of function. In fact reoccurrence rates are as high as 80%.
So what kinds of back pain are there? Broadly lower back pain can be categorised under 3 headings including specific pathoanatomical lower back pain, serious pathological lower back pain and non specific lower back pain.
Pathoanatomical Pathology: 5-10% of lower back pain can be diagnosed, with pain originating from structural pathology affecting things like the vertebrae, discs, ligaments, nerves and other tissues.
Serious Pathology: 1-2% of lower back pain is caused by serious pathology such as infectious and inflammatory disorders or even malignancies. Diagnosis is important with special attention being paid to the nature of the pain and the nature of it's onset.
Non Specific Lower Back Pain: 90% of lower back pain sufferers have no specific structural diagnosis as a cause for their pain. Contemporary evidence supports the notion that lower back pain is not just structural but is in fact associated with a combination of factors including pathoanatomical, physical, psychological, social and behavioural.
So does my back pain mean I should get a scan?
In most cases no. Evidence demonstrates that undergoing an early unnecessary MRI results in a poorer prognosis, an increased likelihood of time off work and an increased possibility of surgery. Fear and pain beliefs have been shown to have a very powerful effect on the outcome of someone with lower back pain. Therefore choosing when it's appropriate to scan is very important, as is the way scan findings are interpreted.
Scans can be misleading as evidence shows a poor correlation between structural findings with levels of pain and disability. Studies conducted on people without lower back pain have shown a high prevalence of abnormal findings on MRI scans (see table below). As you can see by 40 years of age 50% of people without lower back pain have a disc bulge. By 50 years of age 80% of people have disc degenerative changes. Now remember this table includes people without pain. Imagine if we only used scan results to diagnose the causes of back pain!
If you have lower back pain the first thing you should do is to get it properly assessed by a qualified health professional. A good assessment will involve a thorough history and physical examination. A scan may be necessary if there are neurological symptoms, suspicion of a serious pathology or if it is clinically relevant. Otherwise don't rush for a scan as it may not help your cause.
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