Author: Dr Tony Williams FFOM, Consultant Occupational Physician, Working Fit Ltd
Date: 24th October 2015
Spondylosis is the normal degenerative processes in the spine. It includes disc dehydration, disc tears, disc prolapses, end plate changes and osteoarthritic changes in the facet joints. These are expected with age, and are almost universal by age 65. These changes are commonly seen in individuals in their early 20’s.
Back pain is usually unrelated to spondylosis. Where it is related, it is usually due to short term inflammation which is expected to settle. The best treatment for simple back pain is exercise and there is no need to avoid normal activity.
Where spondylosis affects nerve roots or the spinal cord, this can lead to temporary symptoms including pain and numbness, and can occasionally lead to long term or even permanent disability. The great majority of symptoms settle over time, usually a period of a few months, without the need for any treatment.
Surgery to decompress the nerve root or spinal cord is generally very effective and when successful a return to full activity including sport, military, firefighting, police and prison service should be expected.
Most cases of chronic back pain and disability are related to psychosocial factors not physical degeneration. There is no good evidence linking chronic back pain and disability with general spondylosis, unless there is clear objective evidence of ongoing nerve root or spinal cord pathology.
There is good evidence that heavy physical activity is associated with acute back pain but not chronic back pain.
There is good evidence that prolonged heavy manual work, including construction work, can lead to early spondylosis.
There is good evidence that smoking leads to early spondylosis.
There is good evidence that moderate physical activity, typical of military, police, firefighting, prison and healthcare service, results in less spondylosis than high levels of physical activity or sedentary lifestyles.
There is good evidence that increased physical fitness leads to more rapid recovery from back pain and a reduced risk of further episodes of back pain.
There is some evidence that elite sportsmen have an increased prevalence of spondylosis while competing at elite level; there is no evidence that this affects their capability.
There is no evidence that military,police, firefighting, prison or healthcare service increases the risk of spondylosis.
Low back pain is the most common musculoskeletal complaint in the working population, and is probably the least well understood by employees, employers and clinicians. Neck pain is also common and poorly understood. Imaging studies show degenerative changes, and patients are often told they have ‘spondylosis’ when they present with back or neck pain, as if this explains the symptoms and gives a prognosis; it does neither.
Historically, going back more than a hundred and fifty years, employees all got back pain from time to time and just accepted that this was a part of life. Back pain was not considered to be a disease or in any way a medical issue, and people just got on with their lives without rest or treatment and the great majority were none the worse for it. It was only when anatomists identified degenerative changes in the spine, and then when imaging was available, that doctors (in most cases inappropriately) linked the symptoms to the degenerative changes that it became popular to consider back pain as a ‘disease’, offering advice and treatment.
The result is that many people now take time off work, or adjust their workload because of symptoms, and there is a large industry of therapists who treat back and neck pain. There is little or no evidence for much overall benefit from this, just a lot of time off work, and a lot of avoiding activity that is generally shown to be beneficial for recovery. The negatives outweigh the positives.
There are times when a short period of adjustments can help with recovery, and common sense usually applies. It is rare that activity will actually cause harm, as any progressive condition will progress regardless of activity levels. If a disc is going to prolapse, it will do so; avoiding heavy lifting at work may delay this by a few days or possibly a few months, but eventually an activity as innocent as getting out of bed or tying a shoelace will lead to prolapse.
The sections below outline the current state of knowledge about back pain, neck pain and spondylosis, what might cause it, what treatments work and the long term prognosis.
Spondylosis is a general term used to describe the typical degenerative changes seen in the vertebral column, more commonly in the cervical and lumbar spine. The term includes changes in vertebrae and connecting ligaments, intervertebral discs, and facet joints. Key features include osteophyte spurs and bars, disc tears, bulges and herniation, facet joint osteoarthritis, ligament thickening and end-plate changes.
These changes are inevitable in all humans as we age, and can be considered the equivalent to wrinkles in the skin and greying hair. They are a normal and expected finding. Intervertebral discs lose hydration with age, and the surrounding collagen fibres lose elasticity. As a result the vertebral bodies come closer and the annulus bulges, leading to fissures in the fibres which can progress through all layers to allow the nucleus pulposus to herniate through. The altered angle can lead to facet joints overriding, with hypertrophy and osteophyte formation. Increased forces on the vertebral end plates can lead to sclerosis and marginal osteophytes, while ligament hypertrophy may also lead to ossification and osteophyte spur formation.
Most of these structures have little or no sensory nerve connections so symptoms are not expected purely from these degenerative changes. As in many degenerative changes there may be an associated inflammatory process, for example Modic 1 changes at endplates appears to be an inflammatory process lasting up to eighteen months before transitioning to Modic 2 sclerosis or settling back to ‘normal’ (Modic et al., 1988). Annular tears and disc herniation may be associated with initial inflammation lasting several months.
More severe symptoms are related to a combination of these normal degenerative changes and a narrow spinal canal or neural foramina. The result is increased pressure or irritation to the spinal cord (myelopathy) or nerve roots (radiculopathy). These are the pathological changes of medical concern.
Most patients present clinically to their GP, and most diagnoses are based entirely on symptoms without any imaging. X-rays contribute little as they only show gross changes to the bony structures and do not adequately show discs, ligaments and nerves. Much of our current understanding of spondylosis has developed with the use of magnetic resonance imaging (MRI) although computer tomographic X-ray images (CT scans) have played a part. Even with good imaging it is often impossible to determine the cause of symptoms with any certainty.
Clinicians will often offer a diagnosis of a ‘slipped disc’ or a ‘trapped nerve’ to give their patients an answer. These terms have no clear clinical meaning, and the fact that a patient has been given such a label does not mean they actually have any disc degeneration or neural pathology. They are much more likely to have no pathological cause to their symptoms. It is therefore best to ignore any reported ‘slipped disc’ or ‘trapped nerve’ when considering medical diagnosis, aetiology or prognosis.
Clinicians who were training through the 1960’s to 1980’s were exposed to ideas and practices that we now know were unhelpful and inappropriate. Substantial efforts have been made since to re-educate clinicians, however many still persist in giving incorrect and inappropriate diagnoses and advice to patients. The great majority of patients who state categorically that they have a ‘bad back’, a ‘slipped disc’ or a ‘trapped nerve’ have nothing at all wrong with their backs other than the expected changes associated with their age. Unfortunately they have often adopted harmful behaviours as a result of their inappropriate beliefs, avoiding good healthy exercise, leading to weak core muscles, poor posture and exaggerated perceptions of pain (Waddell et al., 2002, Waddell, 2004).
Back pain is very common, and there are major psychosocial factors affecting the presentation, course and prognosis. It is important to distinguish between back pain unrelated to any significant underlying pathology and back pain or other symptoms related to permanent degenerative changes (Savigny et al., 2009).
A study from Japan found substantial levels of lumbar spondylosis increasing with age, see below:
Prevalence per thousand of lumbar spondylosis by age and sex, Japan 2009 (Yoshimura et al., 2009)
A study from US, with a total of only 361 participants also found substantial levels of lumbar spondylosis increasing with age, see below:
Prevalence per thousand of spinal degeneration at various sites with age, US 2011 (Suri et al., 2011)
The evidence for a relationship between degenerative changes and symptoms is conflicting. Symptoms are very common, as are degenerative changes, but there is no absolute link between either of these and loss of function (Waddell, 2004).
Elite athletes have more disc degeneration than non-athletes. One study of current Olympic athletes found 83 % had altered disc signal, 81 % had some loss of disc height, and 58 % had disc displacement (bulge or herniation). Other studies noted a prevalence of 75% disc degeneration in elite athletes and 31% in non-athletes. At least a third of asymptomatic non-athletes in their 20’s have at least one degenerate lumbar disc (Ong et al., 2003).
Back pain is primarily a disorder of middle age, and consulting rates clearly demonstrate this, with a study from Manchester showing a peak before the age of 60. There is some evidence to suggest a link between degenerative changes and pain, but probably only from the onset of degenerative changes where inflammation may be present, indicated by Modic changes at the endplate (Kjaer et al., 2006). As degeneration progresses, pain settles and the individual resumes normal physical activity and no longer consults for back pain, see table below.
Cumulative rate of consultation for low back pain, per thousand, UK 1998 (Croft et al., 1998)
Annular tears are common, and prevalence increases with age. A review of 16 reports including 600 lumbar discs from 273 cadavers found prevalence of annular tears of 7% of people in their 20s, 20% in their 30s, 41% in their 40s, 53% in their 50s, 85% in their 60s and 92% in their 70s (Miller et al., 1988).
Spinal stenosis generally presents later than disc prolapse. While disc prolapse is generally considered to be a problem of early middle age, peaking in the early 40’s, problems associated with spinal stenosis peak later. There are few large studies or reviews that give good epidemiological data. One study from Canada found a mean age of patients requiring spinal surgery for all conditions to be 57.4 (Cheng et al., 2010). Part of the Framingham study found absolute lumbar spinal stenosis (diameter 10mm or less) in 4 % of individuals younger than age 40 and 19.4 % of individuals aged 60-69 (Kalichman et al., 2009).
Modic changes are associated with historical back pain. A Southern Chinese study found an overall prevalence of Modic changes of 5.8%, increasing with advancing age. Eighty three percent of changes were in the lowest two levels. Modic changes in the upper lumbar levels were associated with more disc degeneration, while at the lowest two levels they were associated with age, the presence of Schmorl’s nodes, disc degeneration/displacement and historical lumbar injury. Subjects who were both smokers and overweight/obese had an increased likelihood of Modic changes in the lower spine (OR 2.18, 95% CI 1.10-4.30). The presence of Modic change at the lower lumbar levels were associated with historical low back pain (OR 1.93, 95% CI 1.05-3.54) and with severity and duration of symptoms (p<0.05) (Mok et al., 2015).
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