When it comes to back pain, weigh imaging carefully

When it comes to the assessment of musculoskeletal pain, diagnostic imaging is routinely part of the process. In fact, imaging is so common in our current medical system that it is almost expected. As it pertains specifically to low back pain, this is no different.

Many people believe they need an x-ray or MRI to determine the cause of their pain, and it’s not unusual for doctors to oblige in order to satisfy their patients’ desire for an answer.

What most patients and some doctors don’t realize, however, is the inherent limitation of such studies in actually identifying the cause of symptoms.

Now I want to make it clear that I’m not referring to imaging findings indicating serious pathology. Serious pathologies include fractures, cancer and infections, to name a few, where there is a high correlation between symptoms and imaging findings. Fortunately these are rare, and through the use of advanced imaging we are able to be precise in their detection, providing timely and even lifesaving interventions in the process.

The imaging findings I am referring to are much more common and often given as a diagnosis to those with low back pain. As we have accumulated more information about the prevalence of such findings, serious questions have been raised regarding our ability to accurately correlate them to a patient’s pain.

A recent systematic review offered tremendous insight into this conundrum. It included 33 articles, consisting of 3,110 individuals without a history of low back pain, all of whom had received an MRI of their lumbar spine.

The researchers discovered that many findings we often attribute to low back pain — for example, disc degeneration, disc bulge, disc height loss and facet joint degeneration — are commonly seen in those without a history of back pain, especially after the age of 40. It would appear from this study that these "abnormal" findings could actually be normal age-related changes since their presence doesn’t guarantee that the individual will experience pain.

Several other studies have also confirmed a high rate of false positives on spinal x-rays and MRIs, prompting some experts to suggest a change in the way we interpret and convey these findings to patients.

This was proposed in a 1998 article published in The Lancet, among the most respected and influential medical journals in the world, titled "Should radiologists change the way they report plain radiography of the spine?"

The authors of this article recommended that radiology reports of spinal x-rays come with an explanation regarding the interpretation of several common findings.

Take the finding of advanced disc degeneration, a fairly common diagnosis given to patients when they present to a healthcare provider with low back pain.

The Lancet article stated that when advanced disc degeneration is seen on x-ray, the report should include the warning “Roughly 40% of patients with this finding do not have back pain, so finding may be unrelated.”

Similar explanations were offered for imaging findings such as spondylosis, spondylolisthesis, Scheuermann’s disease, transitional vertebra and others. In every example, 40-50% of patients with that finding do not have back pain, prompting the authors to assert that even when they are present, these findings may be unrelated to symptoms.

With percentages such as these, the odds of determining whether a person is in pain based solely on the fact that they have a certain imaging finding would be roughly equal to chance.

This leads us to the most important question, “If these findings are so common in people without symptoms, how do we know if they are actually the cause of pain when found in people with symptoms?”

The answer is that in the majority of cases, based on looking at the image alone, we simply don’t know. We need more information.

Our technology unfortunately hasn’t progressed to the point where x-rays and MRIs come with flashing red lights showing exactly where the pain is coming from. Instead, it is speculation on the part of the person looking at it to try to determine the cause of symptoms.

Historically this has meant taking an image, determining the most obvious "abnormality," and attributing a patient’s low back pain to that finding. When a sizable percentage of asymptomatic people have the exact same findings, however, such a correlation is difficult to prove.

It would be analogous to convicting someone based on incomplete evidence and becomes especially problematic when the "evidence" is used as the primary justification for costly and invasive procedures.

The way we explain imaging findings can also promote unnecessary disability. Let’s use disc degeneration again, since nearly every person will have it if they live long enough. If patients are told that their disc degeneration indicates "irreversible damage" rather than it being part of the normal aging process, it can create what is known as a nocebo response. Nocebo is the opposite of placebo and describes the phenomenon where patients can actually get worse as a result of their beliefs and expectations.

Ideally, imaging should be used to confirm the findings of a thorough history and physical exam, and in most cases shouldn’t serve as the primary decision-making tool in the assessment and treatment of low back pain. Our goal should be on solving the problem, not simply giving an answer for the sake of giving an answer.

It is important, therefore, that we begin to view radiological imaging in its proper light. Many imaging findings are actually unrelated to the patient’s pain and should be conveyed to them in a manner that doesn’t do harm. Until they are proven as the cause of symptoms, we should take caution when referring to them as ‘abnormal’. Adding an explanation such as “Finding may be unrelated to symptoms, further investigation necessary” to the x-ray or MRI report would be a great place to start.

Dr. Jordan Duncan was born and raised in Kitsap County and graduated from the University of Western States in 2011 with a Doctor of Chiropractic Degree. He practices at Silverdale Sport and Spine. He is one of a small handful of chiropractors in Washington state to be credentialed in the McKenzie Method.

This article originally appeared on Kitsap Sun: When it comes to back pain, weigh imaging carefully