Low back pain is one of the most common reasons for a patient to visit a doctor (2nd in the United States) and is experienced by over 80% of people in their lives. It is an incredibly diverse topic with many causes of low back pain including sprains and strains, joint related-pain, sciatica, disc injuries, disc herniation’s, sacroiliac joint pain, fractures, and other causes.1,2
Low back pain can be characterized dichotomously into mechanical or non-mechanical back pain. The differences indicates if the origin is from the muscles, joints, ligaments, nerves or discs, of the lumbar spine (mechanical), or from other pathology such as infection, cancer, inflammatory arthritis or another non-mechanical causes. The separation helps to identify those patient’s that would be appropriate to treat with manual medicine by a chiropractor or another therapist.
+/- 90% = mechanical low back pain attributable to muscles, ligaments, joints
+/ – 7% = mechanical low back pain attributable to nerves or disc injury
+/ – 3% = non-mechanical low back pain (cancer, infection, fracture, dislocation, rheumatological etc)
Mechanical low back pain is generally treated very successfully but chiropractors, while non-mechanical low back pain necessitates guidance from a medical doctor, sometimes immediately.
Why do we get low back pain
This question is very complex. Researchers still do not know exactly why certain people get low back pain and certain people do not. To keep the issue as simple as possible, and to help you the reader, let us break it down into two areas: what is happening in the back, and what is happening in the brain
Mechanical low back results from either too much force at once (trauma) or too much force over time (repetitive strain)
This type of back pain is experienced with car accidents, sports injuries or falls. In these cases, a chiropractor may be able to help accelerate the healing process and facilitate proper rehabilitation to reduce the risk of further injury.
I witness this cause of back pain in the overwhelming majority of my patients. In most cases, it is the result of improper movement or lifting technique at the gym or with one’s job. Whether it is office related back pain from excessive sitting, or manual labor jobs requiring the same stressful movements over and over again.
Most low back pain results when the back tissues, like the muscles, joints and ligaments are subject to too much force over time. Analogous to the fatigue and pain one would experience when trying to hold a 15lbs weight for hours on end, low back pain is believed to occur similarly.
Cumulative repetitive force causes creep of the tissues. Creep is the process by which a tissue that experiences sustained force over a given time, will lengthen, weaken, and eventually fail. The tissues that hold the back together, experience creep when they are subject to repetitive strain experienced when having to hold the body up straight in a chair, or from bending forward to pick things up repeatedly. The tissues may lengthen and weaken over time and become injured when subject to sustained forces near or at their end-range.
This last point is very important because proper posture and core strength keep the back tissues away from their end-range and reduce the influence of creep. We know this because studies have shown that low back pain often results from scenarios in which the local back muscles do not provide enough stability and support of the spine, and the elements that hold the spine today (joints, ligaments, and discs) are forced to carry to load.
Take a baggage handler for instance. Over a career they bend over to lift thousands of bags, requiring a flexion, rotation and compression force through the spine close to its end range. Baggage handlers often happen to be a population most predisposed to back pain and disc herniation’s
A painful stimulus anywhere in the body is called nociception. The skin nerves and spinal cord detect nociception when there is a pinprick to the finger. Nociception also results when there is physical damage to a tissue such as during a fracture of muscle tear.
Pain is a conscious experience produced by the brain that can result from nociception. The important word is can because in a very confused brain, like fibromyalgia, non-painful stimulus can be interpreted as painful. Depending on what signals are sent to the brain, and what state the brain is in, will determine how much pain is felt.
Pain is a subjective experience and how much pain is experienced by a particular stimulus varies from person to person. It is incredibly important to be aware that part of understanding the origin of back pain means understanding that everything from how you sleep, to job satisfaction, to diet, to family life and even childhood experiences determines how we interrupt nociception.
Ever notice how much more painful things are when you are stressed or do not sleep well? For more information on this topic check out This Video or for those that are really interested, please pick up a copy of The brain that changes itself
To summarize, pain does not necessarily reflect damage to a tissue but it can.
You take 100 people sampled randomly from the street and take an x-ray and MRI. You then ask them if they have back pain. If you then try to accurately guess what people have back pain based on the imaging studies you performed, all the best research says that it is not possible to predict.
More interestingly, almost 30% of the people who were taken from the street will demonstrate evidence of a disc bulge or disc herniation. These issues are commonly associated with excruciating sciatica type pain, but can be completely pain-free. The MRI and x-ray will usually be able to see the very few people who have something seriously wrong, but will tell us very little about what might be causing someone’s back pain.
This example highlights that imaging is very useful when your doctor suspects low back pain that might be non-mechanical in origin based on clinical history and examination findings. Otherwise, x-ray and MRI are not good at telling even the most brilliant of doctors what might be causing your back pain, and even less about how to treat it
Mechanical low back pain can be easily diagnosed through a proper history taking, physical examination, and the use of specific orthopedic and functional tests. Diagnostic imaging is rarely required. Imaging, even MRI, does not generally identify the pain producing structures, or modify one’s most appropriate treatment.
A thorough physical examination should to two things. Firstly it should be able to identify the chief painful structures that are contributing to your pain, whether it is one joint or a collection of structures.
Secondly, and most importantly, it should attempt to identify what factors led to this back pain in the absence of acute trauma. Whether it is reduced range of motion, or strength in the hips, weakness in the core, poor gait or foot mechanics, tightness in the latissimus dorsi or thoracolumbar fascia, or a host of other things. Identifying other areas of dysfunction, and correcting for them should reduce the occurrence of future back pain episodes
While we generally label low back pain from the muscles, ligaments, joints and other soft tissue structures of the low back together as mechanical, it is useful to be more specific in identifying what is the most specific cause.
All of the topics will be tackled individually on separate pages
How long back pain takes to resolve depends on the person and sub-category of back pain that is occurring. Please see each individual back-pain page for a better idea of the prognosis associated with each condition.
Acute mechanical low back pain typically resolves within days to weeks. About one-third of patients are improved substantially after just one week and two-thirds by seven weeks. It is my opinion that most cases of acute or chronic mechanical low back pain resolve within 2-3 weeks of care
Discogenic pain and sciatica have a much less favourable natural history than acute mechanical low back pain. “Symptom improvement from sciatic pain is typically slower, but about a third are much improved in two weeks, and 75 percent after three months . Among patients seeking specialty care, about 15 percent undergo surgery within six months. The role of chiropractic care is to reduce the typical three-month natural history of disc injury to one month or less, and help to prevent the 10-15% of people from going on to be chronic pain sufferers.
1) Deyo, Richard A., and Yuh-Jane Tsui-Wu. “Descriptive epidemiology of low-back pain and its related medical care in the United States.” Spine 12.3 (1987): 264-268.
2) Cassidy, J. David, Linda J. Carroll, and Pierre Côté. “The Saskatchewan health and back pain survey: the prevalence of low back pain and related disability in Saskatchewan adults.” Spine 23.17 (1998): 1860-1866.
3) Coste, J., et al. “Clinical course and prognostic factors in acute low back pain: an inception cohort study in primary care practice.” Bmj 308.6928 (1994): 577-580.
4) Vroomen, Patrick CAJ, M. C. T. F. M. De Krom, and J. A. Knottnerus. “Predicting the outcome of sciatica at short-term follow-up.” British Journal of General Practice 52.475 (2002): 119-123.
5) Vroomen, Patrick CAJ, Marc CTFM de Krom, and J. Andre Knottnerus. “When does the patient with a disc herniation undergo lumbosacral discectomy?.”Journal of Neurology, Neurosurgery & Psychiatry 68.1 (2000): 75-79.