Low Back Pain - Why an MRI Might not Help
Low back pain is incredibly common – about 80% of us will experience back pain in our lifetime (Airaksinen et al 2006). Most people who suffer from low back pain are classified as having “non-specific” pain. A lot of people struggle with this label, as we all love a clear and specific diagnosis. We may feel like a scan such as MRI or CT might just provide “the answer”. With low back pain this is rarely the way it works.
To understand why most types of back pain are considered “non-specific” and scans are often unhelpful, we need to look at what typically causes back pain. Scans are useful for “specific” back pain diagnoses, which means that structural damage can be identified. The fact is that <1% of people with back pain have a serious pathology (like an infection or cancer), and <10% have a structural or “specific” cause (like a disc bulge pressing on a nerve). These are the situations where a scan might shed some light on the diagnosis.
In over 90% of low back pain cases, the search for structural damage yields nothing.
Most types of low back pain are thus regarded as “non-specific” because there is no structural damage to blame for the pain. Yet this is the very “type” of back pain nearly everyone has!
Back pain is typically a functional disorder which requires a different way of looking at the problem. Functional problems, which include things like poor muscle function, weakness, flexibility problems (too tight or too loose), muscle tone problems (spasm vs low tone) and trigger points, are simply not visible in lab tests or imaging.
Excellent – now you probably know that your pain has no serious structural cause but what to do about it?
Clearly doing nothing simply doesn’t work.
If we examine the natural history of low back pain, we learn that it is typically one of chronicity or episodic recurrence with somewhere between 42 – 75% of people still suffering pain one year after their first episode. The incidence of persistent pain rises to nearly 80% after 3 years (Hestbaek et al 2003). There is a common myth that acute low back pain resolves in 4 weeks…. Based on a 1973 study (Dixon et al) that stated, “patients stopped seeing their doctor after 4 weeks”. Not the same thing as the patient had no pain! Persistence is one of the reasons why low back pain is one of the most common painful conditions on the planet.
Due to the recurrent or chronic nature of back pain, spinal pain shouldn’t be ignored. Chronic pain is regarded by some experts as a condition unto itself requiring prompt professional attention (Bonanni et al 2022). Failing to interrupt the pain cycle early and eliminate the causes can lead to chronicity. An example of why early care is beneficial can be found in a recent review of muscle changes in response to back pain (Hodges & Danneels 2019). Multiple studies suggest that early changes in the spinal muscles can be rapidly reversed with gentle low load exercise (in a matter of weeks), but over time persistent inflammation results in progressive deterioration in muscle function and muscle structure (fatty infiltration and fibrosis of the deep back muscles) that may contribute to pain chronicity. This chronic type of change (unsurprisingly) requires a more extensive course of rehabilitation.
The current model of persistent peripherally maintained pain (Tuckey et al 2021: read more in my article here) explains how the inflammation and the tissue dysfunction present in spinal pain causes ongoing symptoms until appropriate treatment is received.
Pain won’t magically disappear until the causes of persistence are remedied.
The idea that low back pain is a “a simple strain that rest fixes” clearly isn’t an accurate for many people, and rest does nothing for the deterioration in muscle function found in many studies. Addressing the inflammatory component of back pain can be done via manual therapy, with the most comprehensive approach to date being Fascial Counterstrain.
In summary the key message from current research is seek care early and don’t ignore pain as it is a warning sign that something isn’t right. Typically, you will need less care and achieve a better result in less time with a more proactive approach to your health. Often the real value of acting early is prevention of recurrence and chronicity, which is the most common outcome of acute low back pain.
Airaksinen, et al. (2006): Chapter 4. European guidelines for the management of chronic nonspeciﬁc low back pain. Eur. Spine J. 2006, 15 (Suppl. S2) S192–S300.
Bonnani R et al (2022): Chronic Pain in Musculoskeletal Diseases: Do You Know Your Enemy? J Clin Med 11:2609.
Dixon A St J (1973) Progress and problems in back pain research. Rheumatol Rehabil 12:165–175
Hestbaek L et al 2003): Low back pain: what is the long-term course? A review of studies of general patient populations. Eur Spine J 12:149.
Hodges P & Danneels L (2019): Changes in Structure and Function of the Back Muscles in Low Back Pain: Different Time Points, Observations, and Mechanisms. JOSPT 49:464.
Tuckey B et al (2021): Impaired Lymphatic Drainage and Interstitial Inflammatory Stasis in Chronic Musculoskeletal and Idiopathic Pain Syndromes: Exploring a Novel Mechanism. Frontiers in Pain Research 23:2:691740.