Understanding Your MRI Results For Lower Back Pain
Lower Back Pain Is Really Common
Understanding your MRI results for lower back pain is vitally important given the growing number of people sent for imaging each year. Lower back pain is one of the most common injuries we see and treat in our clinics. An estimated 1 in 6 Australia’s have chronic lower back pain. Nearly 3 in 10 Australians will experience back pain at some stage. This prevalence is so high that lower back pain is the third highest disease burden in Australia.
MRI Scans Can Be Helpful… Sometimes
Diagnosing lower back pain can be difficult in terms of what specific pathology is causing your pain. Most cases a clinical examination is all that is needed. If you have significant lower back pain, and especially if you have signs/symptoms of nerve compression, your GP or physiotherapist may refer you for imaging of your back. This will most often be an MRI scan.
MRI scans are useful in establishing a diagnosis in combination with a clinical examination. However, they are used far too often and provide little value in the rehabilitation of most lower back injuries.
Indications for getting an MRI
Indications for getting an MRI of your lower back include:
- After 1 to 2 months of leg pain, if the pain is severe enough to warrant surgery
- After 3 to 6 months of low back pain, if the pain is severe enough to warrant surgery
- If the back pain is accompanied by other systemic symptoms such as loss of appetite, weight loss, fever, chills, shakes, or severe pain when at rest. These symptoms may indicate that the pain is due to a tumor or an infection
- For patients who may have lumbar spine narrowing or stenosis and are considering an epidural injection to alleviate painful symptoms
- For patients who have not done well after having lower back surgery, specifically if their pain symptoms do not get better after 4 to 6 weeks.
However, MRIs are use way more than needed, and its not needed for most lower back pain. Too often people with lower back pain are sent for an MRI who don’t really need to, and in some cases the knowledge of their MRI results can make their pain worse.
In other words, in some cases an MRI of your lower back can be worse than useless, it can actually cause you more pain. This is called the nocebo effect.
The Nocebo Effect
The nocebo effect is the opposite of a placebo effect. In a placebo the effect is positive and symptoms reduce based on the expectation that things will improve. A nocebo effect is when symptoms worsen due to the belief or expectation that your condition is bad and will worsen.
Even if this is completely false, your brain can create in increase in pain based on your beliefs about your injury. This is where MRI’s can lead you astray.
Medical guidelines strongly discourage the use of MRI and X-ray in diagnosing low back pain, because they produce so many false alarms
Radiologists can only report on what they see. Although, there is no great correlation between what is reported on an MRI and whether those structures are the source of pain. Take note… MRI’s will often over-report findings and report ‘problems’ or structural changes in your lower back that are not causing your pain.
These results strongly reinforce the idea that something is broken or damaged. This is a common and extremely misguided idea about back pain. Secondly, imaging often fails to clarify the situation, or it actually complicates the diagnostic process. There is so much evidence that lower back pain correlates really, really poorly with these test results. In other words, MRI results cannot accurately identify your pain. That is why its so important to understand your MRI results.
MRI’s Cant See Pain
We know by studying people with no back pain and performing MRI’s on them, that these structural changes can occur without any symptoms or pain. Furthermore, in some cases of people with pain, their repeated MRI scans show little to no change but their symptoms have improved or resolved.
You Most Likely Do Not Need An MRI
My main message here is to understand your MRI results and what they mean. Not all health professionals are good at explaining them to you. Many scans can look bad and the patient is in little to no pain. Likewise, you can be in terrible pain and have a normal MRI.
MRI’s of the lower back can be extremely useful in certain severe injuries like spinal cord compression, spinal nerve root injures, and tumors to name a few. These injuries need timely and correct management, but they are very uncommon compared to the majority of lower back injuries.
The most common reason to get an MRI is to check for neural compromise. A compressed nerve in the lower back may give you numbness down your leg (in a specific pattern depending on the nerve that is pinched), a feeling of pins and needles, and/or weakness in specific muscles (like your calf or the muscles that lift your foot up).
Not all people with nerve compression need an MRI. A significant loss of muscle strength is the most concerning and may be referred for an MRI. Although, if you have full strength with some pins and needles or pain down one of your legs, this will often get better with correct management and without the need for imaging.
MRI Findings In Asymptomatic People
These findings above are commonly reported findings on MRI’s for many of the patients we see. The problem with these findings on MRI is that they can’t tell you if that specific finding is what is causing your pain, or if its just a finding on your scan and unrelated to your pain.
The table above shows that ‘abnormal’ findings can appear on MRIs on people who have no back pain. It also shows that the prevalence of these findings increase with age.
So if your MRI results say you have a Disc Bulge, or Disc Degeneration, don’t worry! Just know that many if not most people that are walking past you in the street will have similar findings and they are fine.
These findings often don’t mean jack. So don’t let them make you worried about your back or fear that your back is fragile and vulnerable… It’s Not!
Overly worrying about your injury and avoiding movements and activities from fear of harm are the most devastating things your can do. These beliefs increase your chance of your lower back pain becoming chronic and taking longer to recover.
If you suffer from chronic lower back pain be sure to get it assessed by physiotherapist. Click Here to read more about managing chronic lower back pain.
Summary
- Lower back pain rarely needs an MRI scan
- MRI scans are used too often in the management of back pain
- Findings on MRI are also seen in the pain free population
- These findings do not correlate with pain or prognosis
- MRI findings that are poorly explained can make your outcomes worse (nocebo)
- Your back is strong and resilient
- Movement and exercise is best
Links
www.mja.com.au/journal/2009/190/9/back-pain-national-health-priority-area-australia
www.painscience.com/articles/mri-and-x-ray-almost-useless-for-back-pain.php
www.spine-health.com/treatment/diagnostic-tests/do-i-need-mri-scan
