The true source of your back pain—is it really what you think?
Do you have back pain and are thinking about getting an MRI? Or maybe you got your MRI and you believe the results spell dread?
The relationship between MRI changes and low back pain may not be so clear-cut. In fact, research shows that changes on an MRI don’t necessarily correlate to pain, while many patients with pain show no abnormalities on MRI. Before jumping to any conclusions, read on for more detail on the complex relationship between what your image shows and whether is it ultimately driving the pain and symptoms you are experiencing.
First, if you’re experiencing back pain, you are not alone. Pain in the lower back is one of the most common musculoskeletal complaints. In fact, 8 out of 10 people will experience low back pain over their lifetime. About 1 out of 4 people experience chronic low back pain (lasting longer than 3 months). Any structure of the lumbar spine that is innervated by nerve endings can cause both low back pain and/or referred pain, which is felt in one or both lower extremities. Some of the more common potential structures that may be involved include muscles, ligaments, vertebrae, facet joints (joints connecting the vertebrae), dura mater ( a membrane that surrounds and protects the spinal cord), and nerve roots.
So how could my imaging be wrong?
Imaging is useful in detecting fractures, abnormal tissue growth (i.e. cancer), inflammation/ bleeding, as well as serious compression of the spinal cord or nerves, which can help direct appropriate treatment. However, 99% of people with low back pain will not have any of these serious conditions. A large percentage will, however, have incidental findings on imaging which are normal anatomical variants, as well as normal age-related changes. In these cases, imaging is much less helpful in identifying the true cause and directing treatment. In fact, several studies have found that pain in the lower back is more strongly associated with factors such as life dissatisfaction, neuroticism, hostility, extroversion, and poor sleep quality than it is with findings on imaging. Thus, obtaining an imaging report can sometimes cause more harm than good. Research shows that patients who undergo lumbar MRI generally have worse outcomes than similar patients who do not have to image. Much of this is attributed to psychological factors, misinformation, and negative emotional responses. One common example is the finding of “dark” T2 signals within the disc on MRI. This is most often a pain-free and benign condition. However, it is labeled degenerative disk disease (DDD) leading many patients to believe their spine is “deteriorating.” In turn, these inappropriate beliefs can lead to a decrease in activity, anxiety, lifestyle changes, a perception of increased pain, changes in motor patterns, and unnecessary surgeries.
So, what exactly does the evidence say?
The exact nature of the relationship between imaging and pain is unclear, largely due to abnormal imaging findings in large numbers of people without pain (false positives). This means that many of the “abnormal” findings are indeed commonly occurring and natural parts of the aging process. One of the more common findings in the lumbar spine is disc degeneration, which is a natural process beginning fairly early on in life. In fact, more than one-third of healthy, normal adults in their 20’s present with degenerative discs on imaging. In some individuals, the rate of degeneration is quicker than others due to a combination of genetic and autoimmune factors, as well as resorption and biomechanical factors. In any case, the volume of intervertebral disc tissue naturally decreases over the lifespan.
Currently, the best available evidence demonstrates the following key concepts:
- Changes in diagnostic imaging are seen in many individuals with NO pain or symptoms.
- Imaging studies (MRI & CT) show herniated disc material in up to 76% of people with NO low back pain or sciatica.
- One-third of patients without pain have some type of “abnormality” in their lumbar spine (disc degeneration, disc bulge, facet hypertrophy, or nerve root compression).
- Several studies have shown that professional athletes (gymnasts, volleyball players, wrestlers, weightlifters, skiers, etc.) have a higher prevalence of disc degeneration and other lumbar abnormalities, but do not have a higher incidence of back pain. In fact, athletes had significantly higher rates of changes on MRI (75-82%) when compared with age-matched non-athletes (54%). However, both groups had very similar rates of reported back pain (50% vs 44%)
- A large percentage of people with pain do not have correlating changes on imaging.
- Less than half of patients who have pain in the lower back also have an “abnormality” identified in their image—this means that the majority who have pain have no associated anatomical changes.
- One study involving horseback riders demonstrated an unusually high prevalence of lower back pain, but no conclusive MRI evidence to point to disk degeneration, spondylolysis, spondylolisthesis, or pathologic changes of the paraspinal muscles of the lumbar spine—imaging offered no explanation for their symptoms.
- In one long-term follow-up study, 80% of athletes and 40% of nonathletes reported pain at baseline. Fifteen years later, 71% of athletes and 75% of non-athletes reported pain. At both points, athletes and non-athletes had similar rates of disc degeneration and the majority of the abnormalities seen on follow-up MRI were already present at baseline. This means that despite very few changes on images, the non-athlete group almost doubled in reports of pain—once again imaging could not identify the cause.
- Research has shown MRI findings are not related to the intensity of pain or extent of disability, (i.e. larger herniation does not equal more pain).
- Several studies have found that both vertebral endplate changes and large extruded disc herniation (both believed to be causative factors in low back pain) are equally distributed between healthy subjects and those with disabling back pain. This means that as many patients without pain as those with pain had these changes on MRI and the changes did not correlate with severity of sciatica.
- Those with both pain and identifiable changes should be cautious, as the changes may not be the direct cause of the pain.
- Even when abnormalities are identified, it is difficult to determine whether they are the direct cause of pain, as evidence has shown that many anatomical variations on MRI are not associated with symptoms
- Many patients undergo unnecessary surgery to correct an incidental finding on imaging and still have pain because the original cause was something other than what was identified and wasn’t addressed (poor posture, decreased core stability, muscle spasm, etc.)
As one can see the current research on medical imaging does not support the notion that what is seen on the image correlates strongly with what the patient is experiencing. In fact, it has been shown that a thorough physical examination leading to a mechanical diagnosis can be just a sensitive and specific in identifying the cause of your symptoms. An evaluation by a qualified Doctor of Physical Therapy can help reveal the underlying biomechanical deficits that may have contributed to your condition and prevent it from recurring in the future. Some of the benefits of physical therapy include pain relief, increasing mobility, strengthening of the core and lumbar stabilizers, and increasing balance and functional movement.
At Fox Physical Therapy, our board-certified therapists specialize in treating and relieving low back pain. Contact us today to find out how we can help you feel better.