Smile you're on camera
2009
The value of x-ray and MRI remains a hot topic in the back pain world. There is no doubt that these medical imaging technologies can play a great role in diagnosing certain back pain conditions and guiding subsequent treatments. However, there is more and more evidence emerging that in most cases MRIs and in particular x-rays do more harm than good.
Since Marie Curie and fellow researchers discovered radioactivity in the late 19th century, science has come up with some amazing applications for this radioactivity. Some were simply very scary and dangerous, while others have improved the lives of many people, such as Wilhelm Conrad Röntgen’s discovery that you can identify bony structures with x-ray radiation. He took the very first x-ray, or Röntgen photo as they are called in many languages, of his wife’s hand.
Since then, medical imaging technology has made good progress and there is virtually not a single structure in the human body that we cannot take some sort of a photo of (without opening the body). Using ultrasound, CAT scans, MRI scans, x-rays or combinations of these we can get pictures of our bodies that wouldn’t be out of place with the photos displayed at Tate Modern.
However, with these advances in technology, we have come to expect a photo or image of every disease or condition we may suffer from. This is where things become a bit more complicated, especially for conditions such as back pain. We can’t visualise pain and it is unlikely we will ever be able to make a pain-o-graph.
As a substitute we make images of structures that may give rise to the pain; x-rays give us a view on the vertebrae and other bony structures in the back, MRI provides information on the softer structures and even ultrasound can be used to look inside our spinal column. With these technologies, we have been able to get a very good idea of what all the structures in our back look like and how they work. We know what a ‘normal’ back looks like and we know what is ‘abnormal’. However there is a huge grey area between ‘normal’ and ‘abnormal’ and furthermore back pain happens in people with ‘normal’ and ‘abnormal’ structures in their backs.
If we take MRI scans or x-rays from a random group of people, we would find abnormalities in a significant number; some may have degenerated intervertebral discs, others may have osteoporotic bones, others pronounced curves in their spinal column, etc. It is most likely they will have had these ‘abnormalities’ for quite some time, but simply never known it. It is also likely they may have had these ‘abnormalities’ without experiencing any back pain.
The opposite situation is just as unhelpful. Taking an MRI or x-ray of someone with back pain and not finding any ‘abnormalities’ is not useful. Surely the fact that no serious abnormalities (such as cancer or fractures) have been identified can take away some of the concerns people may have, but they are still in the dark about where their back pain is coming from.
The first myth to bust is the assumption that medical imaging is used to find out where the pain is coming from.
So how can medical imaging assist people with back pain and their clinicians? The first myth to bust is the assumption that medical imaging is used to find out where the pain is coming from. As explained above, this link between structures and pain is often very difficult to establish. X-rays and in particular MRI scans should only be used to exclude the small chance that back pain is caused by a serious ‘abnormality’ that would be visible on such a scan. These include cancer, fractures, infections and certain inflammatory conditions such as ankylosing spondylitis. In that sense a negative scan should be seen as good news. But ‘trawling’ through such scans to find other abnormalities often results in false information, since these are only seldom linked with the pain people experience.
On top of that there is a good argument to limit the use of x-rays and MRI scans since an over-exposure to radiation is a serious health risk. In the past 25 years, the exposure to radiation during medical procedures in the US has increased 7-fold. Fortunately the UK is not as much of a mass consumer of x-rays, CT scans and MRI as the US, but there is nevertheless a good reason to carefully weigh the potential benefits of such scans with the well-documented risks.
It is therefore not surprising that a recent review of the scientific literature concluded that “…clinicians should refrain from routine, immediate lumbar imaging in patients with acute or sub acute low-back pain and without features suggesting a serious underlying condition”. In other words, doctors are very able to manage most back pain without the use of imaging techniques, unless there is good reason to believe that conditions such as cancer, infections, fractures or inflammatory diseases are responsible for the pain (see the article by Chou and colleagues in the February 2009 edition of The Lancet).
The other important lesson from this is that doctors and others, requesting an x-ray or MRI scan for their patients, have a great responsibility towards their patients to explain why they have done so and what the patient can expect from the outcome. A doctor’s comment that “You have black discs” sounds a lot more alarming than “Your discs look normal for someone your age”, although both are valid interpretations of an MRI scan. Flagging up any structural abnormalities on scans is only useful when there is good reason to believe that these ‘abnormalities’ play a significant role in the pain you experience and that surgery or other treatments can ‘amend’ these ‘abnormalities’.
Medical imaging technology will no doubt continue to play an important role in diagnosing back conditions. However, the research to date indicates that it should not be used as a blanket approach for all back pain and both patients and clinicians should be clear why these scans are performed. In the right context, an x-ray, MRI or any other scan is a valuable tool in helping people with back pain, but in the wrong context, people may be misguided.