Why your back scans might not be helpful in diagnosing your back pain!
More than 80% of the population will experience low back pain in their lives. It’s so common that around 3 million Australians are suffering with it right now. Many of these people, if the pain is moderate-severe, constant and chronic (last more than 3 months), will access a health care provider for management. Often when the back pain is affecting the way you move, work or enjoy life, people can feel quite anxious and wonder if it will ever get better. Most importantly we want someone who can tell us what’s wrong and how to fix it!
The low back is a simple enough region. It’s made up of 5 vertebrae that sit on top of your pelvis. Between each vertebra are discs that provide cushioning and covering these discs and vertebrae to provide support are muscles and ligaments. There are also joints that sit behind your vertebrae called facet joints that support your back and limit how far back it can extend. Between your vertebrae and facet joints sits your spinal cord which deviates off into the infamous sciatic nerves down both legs. So if we know all the structures of the back and how they work, then why is low back (especially chronic) pain so hard to manage?
There are a lot of high quality scientific papers out there that devote themselves entirely to this question. A simple explanation would be that pain is caused by irritation of nociceptive (pain sensitive) nerves that transmit signals to the spinal cord en route to the brain. But the truth is far more complex. Your pain is influenced by a lot of things (e.g. anger, depression, work stress, financial issues, illness, fatigue). It is even influenced by the country you live in, the food you eat and the kinds of people and mentality you surround yourself with. In many cases of chronic low back pain, the anatomy of the area may have healed (e.g. bulging disc) but unless these other issues that affect the pain response are sufficiently taken care of; our pain can remain for a long time – sometimes decades! Sorting out these pain influencers is key.
So now you can see why you might feel pain in your low back even though there may not be any issues on the scan. But what if the scan says there is an issue there? Is that definitely the cause of your pain and the reason why you are not improving?
Brinjikji, et al. 2014 did an epidemiological study on a large population who had NO SYMTPOMS of low back pain. They did numerous MRI scans on a number of different subjects and across different age groups and found some interesting results. If you don’t have any pain in your back, then you can’t possibly have any disc issues right?
As the results of the study below show, even young people with healthy backs and no symptoms of pain can have disc bulges. In healthcare we have long thought that disc bulges were the cause of serious low back pain and even led to sciatic symptoms. So why do 40% of pain free 30 year olds have disc bulges and NO symptoms? We summarise that these changes are a normal part of the aging process in the same way some young people start getting grey hairs earlier than others. Not ideal but also not a great cause for panic.
In conclusion, if you see your doctor or physiotherapist and you get a back scan on a chronic low back problem, the issues you see on the MRI might just be a normal occurrence within your body and not related to your pain at all! Of course, in many instances scans are still useful in diagnosing some problems in your back. But you should always be critical of scans and if the results don’t match up to your pain symptoms, they may not be relevant. Always talk to your healthcare provider if you have questions. Remember, physiotherapists are experts in rehabilitating back injuries with scientifically proven interventions to provide best relief. A thorough clinical examination of your symptoms by a trained professional is often superior to the findings on a scan. Now you know!