Low back pain - What is it and what are the risk factors?
Low back pain is complex. If we had a simple solution, it wouldn't be the leading cause of disability worldwide.
So, what is low back pain?
Low back pain is defined by the location of pain, typically between the lower rib margins and the buttocks creases. It can be accompanied by pain in one or both legs and some people with low back pain have associated neurological symptoms in the lower limbs. Low back pain is a complex condition with multiple contributors to both the pain and associated disability, including psychological factors, social factors, biophysical factors, comorbidities, and pain-processing mechanisms (Lancet, 2018).
Low back pain is extremely common. It’s estimated that 85% of adults will experience it at some point in their lives and 7.3% (540 million people) currently have low back pain (Lancet 2020). Of these cases, 85-90% are considered non-specific low back pain.
This poses the question, what is non-specific low back pain (NSLBP)? Due to the complexity of low back pain, a pathoanatomical cause of low back pain usually can not be determined. NSLBP is a term of diagnostic honesty acknowledging our inability to find a specific source of pain.
The diagnosis of NSLBP is not meant to minimize the patient’s experience, but rather indicate that specific causes such as spinal fracture, infection, cancer, axial spondyloarthropathy, or radiculopathy have been ruled out, and reassure the patient that nothing serious or sinister is causing their pain. In fact, NSLBP should be viewed as a fairly benign part of daily life.
If you’ve sought medical advice for your low back pain there is a high likelihood you’ve been told you have a disc herniation, bulge, or extrusion. In only a small percentage of low back pain cases can we determine if disc pathology is likely the culprit. These are cases of radicular pain or radiculopathy. Radicular refers to nerve root involvement where there is also a presence of concurrent leg pain (oftentimes worse than the low back pain) and/or clear neurological symptoms. Radicular pain is most commonly caused by disc pathology and is estimated to be the source of low back pain in roughly 10% of cases (Ferreira 2019). The graph below from Ferreira & colleagues shows the discharge diagnosis given to 14,024 patients who visited the emergency room for low back pain between January 2016 and June 2018 at three different hospitals in Sydney, Australia.
Note that of those given a lumbar spine diagnosis as the primary source of their low back pain, 85.4% were NSLBP, 10.1% were radicular pain, and 4.5% were found to have serious spinal pathology.
In cases of NSLBP, is it not possible to accurately determine if disc pathology is the cause of someone’s pain. For example, (Brinjikji 2015) found that 50-70% of pain free individuals, aged 40-49, had findings of a disc bulge or disc protrusion on MRI. Another study by (Brinjikji 2015) found that nearly 20% of asymptomatic patients 50 years of age or younger had disc protrusion compared with nearly 40% in the symptomatic group. This study demonstrates that there may very well be a correlation between disc pathology and NSLBP, but this should not be interpreted as causation. More importantly, diagnosing these findings on MRI is unlikely to change management.
Degenerative joint disease (DJD) and degenerative disc disease (DDD) are commonly given diagnosis. These age-related adaptations are present in an overwhelming number of the asymptomatic population. The chart below from (Brinjikji 2015) a systematic review demonstrates age-specific prevalence estimates of spine imaging findings in asymptomatic patients. Disc degeneration is present in 40% of asymptomatic twenty-year-olds, 80% of asymptomatic fifty-year-olds, and 96% of asymptomatic eighty-year-olds, which I would argue is likely 100% of those eighty years or greater.
MRI is highly sensitive in detecting degenerative changes; however, this study and previous studies demonstrate that it may not be possible to distinguish between age-related degenerative changes and pathologic, pain-generating degenerative changes.
Labelling these anatomical changes as “degenerative” also suggests that there is something wrong with the structure it refers to. The chance of finding these changes on MRI or X-Ray increases as we age, but again, the prevalence of these findings do not correlate strongly with the patient’s reported level of pain or disability. So instead of degenerative changes, we should be using the term normal age related changes.
Take skin wrinkles for example. Your doctor wouldn’t tell you that you have degenerative skin disease. Wrinkles are normal, age-related changes that occur over time.
Who’s At Risk?
It should be clear by now, in most cases, there is no singular cause of back pain. Back pain is caused by a combination of biological, psychological, and social factors. This is known as the biopsychosocial model.
From a biological standpoint there is often a mismatch between what the person asks their body to do and what they are prepared to do or tolerate. This may show up in occupational work, weightlifting, military fitness testing, or frequently seen with weekend warriors. These are issues related to workload management.
How can we reduce the risk of these occurring? Well, in simple terms, begin at a level of activity that is well tolerated and then build slowly from there to increase the likelihood that you are ready to handle a given task.
It should be noted that just because a certain tissue is sensitive, it does not mean that it is damaged or that you will cause harm if the activity is continued. Pain does not equal harm, in most cases, but rather an alarm system that is in place to drive behavioral change. The behavioral change most appropriate with low back pain is to remain physically active within your individual tolerance and then slowly build up from there, giving your body a chance to adapt to the new demands.
Psychological & Social Factors
Psychosocial factors have become increasingly recognized as important contributors to the pain experience (Kraljevic 2011). These factors include depression, anxiety, catastrophizing (ie, an irrational belief that something is far worse than it really is), low self efficacy (ie, belief in one's ability to influence events affecting one’s life), and fear avoidance (ie, fear of pain leading to avoidance of activity). The presence of these factors in individuals presenting with low back pain is associated with increased risk of developing disability (Lancet, 2018).
Many of our beliefs about low back pain are learned threats from close friends, family members, and oftentimes medical providers. This process of learned behavior begins in childhood. Children learn pain-related beliefs and behaviors by observing their parents’ pain behaviors and in turn, adopt similar behaviors in response to their own pain (Stone 2016).
This likely does not come as a surprise, as many of us have a friend or family member who grew up with one of their parents having a “bad back” or “bad knees” and then ended up developing a similar chronic condition themselves. These narratives about pain are harmful and pervasive, and oftentimes lead to fear avoidant behavior. Activity avoidance in response to pain may perpetuate symptoms and lead to long term disability.
Occupational influences also seep into our unconscious thoughts about pain and injury. Brochures and flyers showing “proper lifting technique”. “Don’t lift with your back, that’s dangerous! Lift with your legs.”
The same can be said for social media. “Social influencers” claiming to be experts, warning their followers to not round their back! “Be careful. You only get one spine!”
These narratives are harmful, and this isn’t even the worst of it!
One survey in 2017 asked 130 individuals with persistent back pain, “What is your understanding of why your low back pain is persistent or recurring?” Four clear patterns of thinking were found:
Broken Machine - the body can break and sometimes be repaired. Low back pain persists because something is physically defective.
Low back pain as permanent/immutable - Low back pain is conceptualized as a static or fixed entity that once ‘broken’ it cannot be ‘fixed’. Low back pain is permanent.
Low back pain is complex - multiple factors can contribute to persistence of Low back pain, including biomechanical, psychosocial, and cultural factors.
Very Negative - Low back pain is abnormal, catastrophic, and has a large effect on life.
The most alarming finding from this survey was that 89% of participants indicated that they learned these beliefs from healthcare professionals (Setchell 2017). So not only are we being inundated with harmful information from social media, the workplace, and our loved ones, but we are also receiving unsubstantiated information from medical professionals. This is a huge problem in healthcare and one that needs to be corrected if we wish to reduce the global burden of low back pain.
Lifestyle factors, such as smoking, obesity, and low levels of physical activity, that relate to poorer general health, are also associated with occurrence of low back pain episodes (Lancet, 2018). Unfortunately, roughly 80% of Americans do not fulfill the U.S current weekly Physical Activity Guidelines (Piercy 2018). Part two of this series will discuss what steps you can take to reduce the risk of developing disabling low back pain, possible treatment options, and how you can play an active part in reducing the global burden of low back pain.
The majority of individuals will experience low back pain at some point in their life.
90% of low back pain is considered to be Non Specific Low Back Pain. NSLBP is a diagnosis that accurately represents the complex nature of most low back cases and excludes more emergent causes such as spinal fracture, infection, or cancer.
Imaging such as X-Ray and MRI does not accurately and reliably demonstrate the source of someone’s low back pain, in most cases.
Social media, Dr. Google, occupational safety information, and friends and family are not reliable sources of information for low back pain. Unfortunately, many healthcare providers are not much better. More work needs to be done to improve the narratives around low back pain.
An emphasis needs to be placed on remaining active and continuing participation in meaningful activities, reducing time away from work, and improving overall health in order to reduce the risk of low back pain becoming disabling.
If you found this article useful, please share with a friend, family member, or colleague to help spread evidence-based information. My goal is to play a small part in reducing the global health burden of persistent pain.
- Edited by Dr. Lacey Venanzi & Geronimo Bejarano
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Vos et al. (2020). Global Burden of 369 Diseases and Injuries in 204 Countries and Territories: A Systematic Analysis for the Global Burden of found that 50-70% of pain free individuals, aged 40-49, had findings of a disc bulge or disc protrusion on MRI. Another study adone by