Medical imaging for low back pain: Not the whole picture

Illustration by Chloe Ma for rehabINK.

Commentary

By Stephanie Scodras


I love data. I love charts, trends, and excel sheets. I love my Fitbit. And I am not alone in this. Increasingly, people have become interested in capturing their personal data, especially when it comes to their health. This interest may explain the surge in successful companies like ‘23andme’ that offer at-home DNA testing to learn about your ancestry and health predispositions.

However, our fascination with personal data may have also contributed to the widespread use of medical imaging technology for the diagnosis and management of common orthopaedic problems like low back pain (LBP) (1). The assumption is that if we can know what is going on inside our bodies, then we can manage and track health issues more effectively. Unfortunately, this is not always the case when it comes to medical imaging for LBP. More data does not always mean better information for healthcare decision-making.

Low back pain is a common and costly condition that affects an estimated 4 out of 5 people in their lifetime and which has a high recurrence rate (2-4). In other words, most people will suffer from LBP at some point in their life and likely more than once. As a physiotherapist, I see how common LBP is and how it negatively affects people’s lives. Low back pain can limit a person’s ability to participate in their regular work and leisure activities, so it is no wonder that about half of the people with LBP seek help from a medical professional (2). Given the impact of this condition, medical imaging has become a popular technology used to address the issue.

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Image source: Larm Rmah (Unsplash)

Historically, medical imaging has been characterized by discoveries that have advanced the healthcare fields significantly. Beginning in 1895 with X-rays that allowed broken bones to be visualized, to angiograms that help locate and treat heart blockages, and to functional Magnetic Resonance Imaging (fMRI) developed in the late-twentieth century that can track brain activity during tasks, medical imaging has evolved into an invaluable tool for the diagnosis and management of many injuries and diseases (5). However, just because a technology is available does not automatically mean that its potential benefits outweigh its risks of use.

Without a doubt, medical imaging plays a key role in confirming the presence of emergency medical conditions related to back pain. Physicians, physiotherapists, and other front-line healthcare professionals are trained to screen patients for “red flags” that might indicate serious underlying pathologies like bone fractures, cancer, or spinal cord compression; healthcare providers ask about medical history, significant and unexpected weight loss, loss of sensation or strength in the lower body, and the inability to control the bowel or bladder (6).

Imaging is crucial in these instances. For example, X-rays can identify spinal fractures, and MRI and computed tomography (CT) scans – medical technologies that visualize slices of the spinal anatomy – can detect tumors or spinal cord compressions that may require swift intervention (5,6). But these cases are the minority, making up only a small proportion of LBP complaints (7). For the far more common and non-emergency LBP cases, imaging does not give the whole picture.

To explain further, consider how visualizing the deep structures of the spine became common practice given the rise in availability and popularity of medical imaging technologies in the mid- to late-twentieth century (1). Intervertebral discs sit between the bones of the spine. They provide shock absorption and facilitate back mobility (8). They are made up of an inner flexible portion that behaves as a solid or liquid depending on the mechanical load, and an outer fibrous layer (8). Advancement in medical imaging made it easier to detect if the intervertebral disc material was extending into the spinal canal (disc herniation) or thinning out (degenerative disc disease).

If you are experiencing LBP, wouldn’t you want to know whether you have a herniated disc or degenerative disc disease? The instant answer is, “Of course I want to know!” Yet this option is an example of “just because you can do something, doesn’t mean you should,” because these diseases are in fact quite common (9) and having this information does not necessarily help you get the right treatment (10).

“Just because you can do something, doesn’t mean you should.”

But why is this the case? As evidence has emerged over the past few decades, we now understand that “abnormal” imaging findings might actually be… normal. For example, in one study of adults without back pain, researchers found that over half of the participants had at least one visible disc herniation on their MRI scans and that the occurrence of these findings increased with age (11). Another study found that low back “abnormalities” like disc herniation, disc degeneration, and spinal canal narrowing were not predictive of future LBP (12).

In yet another study which included over 1000 adults, disc degeneration was present in 40% of individuals under 30 years old and in over 90% of people aged 50-55 (9). Researchers concluded that disc degeneration is a normal part of aging, and that these types of changes should be expected in  imaging results (9). Interestingly though, researchers did find a relationship between the severity of disc degeneration and herniation with occurrence of LBP symptoms (9) – Aha! So we might infer that there is some benefit to imaging for people with LBP because it may reveal how severe the problem is. Not quite though, because performing medical imaging for non-emergency related LBP can lead to unnecessary harm.

For example, a study of workers with LBP found that early MRIs were associated with increased length of disability, medical costs, and surgery even when accounting for pain severity (10). These findings point to a potential iatrogenic effect of imaging, meaning a negative effect associated with the diagnostic or treatment procedures that occurs apart from the illness or condition itself (10). As a physiotherapist, I have seen clients who have developed a fear of certain healthy activities like walking, bending, or lifting simply because they have been told that they have disc herniation or spine degeneration. The mounting evidence against imaging for LBP has tipped the scales away from the practice – so much so, that the official recommendation is currently for imaging not to be done for people with non-emergency related LBP (13).

This process of practice reversal is often called de-adoption – an interesting phenomenon that occurs in healthcare when evidence becomes available that what we have been doing is no longer what we should be doing (15). Choosing Wisely, an international campaign which circulates evidence-based recommendations to decrease the use of low-value healthcare practices (14), recommends that physicians do not order medical imaging for people with non-emergency related LBP. The reason against imaging here is that it does not help patients get better faster but may actually cause harm by delaying recovery and increasing unnecessary healthcare usage (13).

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Image source: mohamed_hassan (pixabay)

Given these recommendations against medical imaging for LBP, what care is recommended? Evidence shows that the best advice for individuals with LBP are: providing education and reassurance that LBP is normal and that individuals should feel better within a few weeks, managing pain with over-the-counter pain relievers, and educating about the importance of staying active (e.g., no bed rest) (7). Patients are receptive to education about why medical imaging is not necessary for most cases of LBP (16); these recommendations highlight the importance of education for healthcare providers and for patients in the management of LBP.

Low back pain is just that – a real pain. It can affect people in significant physical and emotional ways by limiting one’s ability to do the activities that they want and need to do. Although medical imaging technology has been a keystone in the advancement of healthcare fields, for non-emergency related LBP, we must recognize the risks of imaging against its few potential benefits.

As our understanding of medical imaging for non-emergency LBP has become clearer, the best care is to focus on education, pain management, and physical activity, so that people with LBP recover in less time with fewer resources wasted.

Acknowledgements

Featured illustration by Chloe Ma for rehabINK.

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To refer to this article, it can be cited as:

Scodras S. Medical imaging for low back pain: Not the whole picture. rehabINK. 2020;8. Available from: https://rehabinkmag.com.


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