Royal Bournemouth and Christchurch Hospitals NHS Trust, Forest Dene Unit, Fairmile Road, Christchurch, Dorset BH23 2JX, UK
Disabling low back pain in industrialized societies has become the focus of wide-ranging research over the last 15 yr. The importance of its social and financial impact is not reflected in the current UK health provision agenda. The economic impact of days lost from work, invalidity benefit and health service utilization as a result of chronic back pain is enormous, having risen rapidly since the mid 1970s [1]. Benefit payments have plateaued in the last 3 yr [2]. The cause is unclear, but may be due to the All work test and the use of acute back pain guidelines.
The 1-month prevalence of low back pain is 3537%, with a slightly higher female prevalence. Lifetime prevalence is estimated at 59%, with peak prevalence between 45 and 59 yr of age [3]. Around 10% of back pain episodes lead to consultation with a general practitioner, and 90% of patients have improved at 1 month [4]. Although patients stop seeking care, the majority continue to be symptomatic at 1 yr, with only 21 and 25% completely recovered with reference to pain and disability respectively. This suggests a chronic fluctuating symptom course with intermittent flares [5].
Psychological distress factors are associated with back pain, being more prevalent in sufferers [6], a strong predictor of outcome in chronic patients [7] and appearing to influence the development of new back pain symptoms [8]. Risk factors for back pain include mechanical strain on the spine from heavy lifting, repetitive lifting, twisting and vibration, including driving. Static work postures, prolonged standing or walking, road traffic accidents and falls also show a link. The link with obesity is tenuous but smoking is a consistent factor, as is a previous history of back pain and parity [913]. Other psychosocial features are poor social and educational status, and previous sexual or physical abuse [1416].
Risk factors for chronicity of low back pain include high levels of psychological distress in the episode, premorbid association with dissatisfaction with employment or work status, unemployment, poor self-rated health and low levels of physical activity. During an episode of pain, poorer outcome is linked with reported widespread pain, radiating leg pain, poor spinal movement and a longer duration of symptoms before consultation [17]. Not surprisingly, a favourable outcome is associated with fit males with a short episode of back pain who are happily employed [18].
Psychosocial risk factors (yellow flags) for chronic symptoms and disability have been developed as part of the assessment for patients who are not improving. They are not exclusive to physical risk factors and identify people who need a different approach in preventing fear of movement, illness behaviour and prolonged distress [19, 20].
Clinical guidelines for back pain management were first made in the report of the Quebec Task Force on Spinal Conditions 1989 [21]. It highlighted the lack of evidence for many physical treatments, recommended against bed rest and suggested a chronological treatment plan including psychosocial assessment in non-resolving pain. The subsequent US AHCPR back pain guidelines recommended a detailed conservative approach but produced considerable backlash in the USA. The UK CSAG report places more emphasis on early activity and exercise, the Dutch defer manipulative treatment to 4 weeks and promote self-help, whilst Israel places emphasis on multidisciplinary assessment and avoids manipulation in its guidelines given as the Ten Commandments [1, 20, 2326].
Despite the considerable time and effort invested in these documents, there is little evidence of their use or impact. Circulation to the relevant practitioners has been poor, and there are implementation difficulties in changing practice and the availability of necessary services [27, 28].
Back pain triage is the medical model of diagnosis used to exclude serious pathology. History and examination are used to identify diseases of an inflammatory, neoplastic, infective or metabolic nature, in addition to specific causes of mechanical pain, symptomatic disc prolapse, stenosis and instability. This remains the best diagnostic tool despite poor observer reliability [29]. The sensitivity of the standard clinical history and examination is low, with no standard symptom complexes emerging from critical evaluation despite eminent texts on the subject [3032]. Red flag symptoms and signs are indicators of serious pathology [33, 34]. Around a third of patients report a risk factor, and 110% of these patients will have pathology [35]. Reassessment of these symptoms and signs is of high importance at each patient review [29].
The proportion of patients with identifiable causes of back pain varies according to the attribution of symptoms to degenerative change, but most groups confirm a low incidence, of 25% or less [21, 36]. There is little correlation between X-ray degenerative change and symptoms [3739].
Specific causes of mechanical low back pain may respond to conservative treatment and in selected cases to surgery. Sciatic pain has multiple potential causes but the most common is nerve compression. The mechanisms of sciatic pain include mechanical injury, inflammatory response [4042] and obstruction to epidural veins leading to perineural fibrosis [43]. The natural history of disc prolapse is one of spontaneous resorption over time [41, 42] and epidural anaesthesia gives temporary pain relief but does not improve outcome [44]. Where imaged pathology corresponds with symptoms, the results of surgery are better than those of conservative management at 1 yr. Patients with lesser symptoms have a similar benefit with surgery or conservative treatment [45].
Spinal symptoms due to central or lateral canal stenosis are similar. There is poor correlation between symptoms and the severity of findings on imaging [46]. The condition frequently has a slow or static course and there is no detriment to the patient in delaying surgery [47]. Mechanical sacroiliac joint pain is identified as a cause of low back pain, differentiated only in that it may cause referred pain in the groin [48]. Mechanical facet joint syndrome remains unproven in terms of reliable history, examination findings and treatment [49].
Once a suspicion of significant disease is aroused, then imaging is appropriate. X-ray is useful in determining inflammatory sacroiliitis, vertebral fracture and mobile spondylolisthesis. Bone scan may confirm low-grade inflammatory change, infection, tumour or sacral fracture. MRI is essential for viewing nerve or cord compression, the extent of infection (e.g. paraspinal collection) and some tumours, particularly myeloma [50].
The vast majority of patients will have non-specific low back pain with no identifiable cause of their low back pain. Patient triage should be used to determine both the physical characteristics of the pain and the psychosocial factors, including patient cognitions. Once serious pathology has been excluded, the majority of patients will need to develop ways of coping with pain and impairment on a long-term basis, thus participating in their recovery process.
This may conflict with the patient's expectation of an exact diagnosis, specific treatment and complete relief of pain. Failure to provide this model results in the patient believing their pathology has been missed or that their symptoms are doubted by their doctor, and thus that their symptoms have not been given legitimacy [5153]. Attempts to provide a more specific diagnosis e.g. arthritis or worn disc, lead to more chronic symptoms, expectations of specific treatments and patients using jargon in an idiosyncratic way [54]. Unsuccessful treatments add to the belief that the cause of their pain is not known and contribute to the psychological distress of chronic pain [55].
Engaging the patient in his or her own recovery is of utmost importance. It requires the clinician to listen to and educate the patient [56]. The patient presents in the context of their psychosocial stresses, fears and beliefs. For many doctors this is a step beyond their training to identify and treat specific disease [57]. Patients have to be encouraged to find pain relief strategies whilst becoming more active. They need to be convinced of the lack of association between pain on activity and further damage to the spine [58]. These fear-avoidance beliefs mediate the relationship between pain and impairment [59].
A proportion of back pain patients develop increasing impairment and disability. These small numbers of people use the majority of the financial and health-care resources devoted to back pain. Less than 50% of back related disability is related to physical impairment, and a significant proportion is related to psychological distress and illness behaviour [59]. Psychological emotional distress (anxiety and depression) is expressed as heightened awareness of bodily symptoms and increases with the duration of symptoms and the number of specialists seen. Depressive symptoms are of an atypical reactive type and respond poorly to psychotropic drugs [60].
Waddell described the illness behaviour that chronic back pain patients demonstrated as inappropriate symptoms and signs. These are a further indicator of distress and do not indicate malingering [61]. Women tend to inappropriate symptoms and men to signs when back pain is associated with depression and medicolegal proceedings. The illness behaviour may add to the disability and become counterproductive [60, 61].
The reasons why and when patients seek help and why individuals react so differently to pain require further research. General practitioner consultation is associated with the level of pain in the first 2 weeks of an episode. In the following weeks the level of disability is important, but by 3 months depression is the most important variable for consultation [62].
In managing a patient with non-specific low back pain, a confident practitioner [63], after routine triage, should reassure the person that there is no serious disease. Recommended management is to remain as active as possible and avoid bed rest [64], and this should be backed up by written information, e.g. The Back Book [58].
Routine imaging is not recommended. X-rays show structural degenerative changes, but these should not be given clinical significance as similar degenerative changes are seen in asymptomatic individuals [3739]. MRI scans similarly do not show correlation with back pain in relation to disc bulging and protrusion. However, severe disc protrusion or extrusion is rarely found in asymptomatic individuals, and neural compromise is the best predictor of symptomatic disc protrusion. Disc bulge is found in 25% of 20- to 30-yr-old asymptomatic individuals and in 60% of 40- to 50-yr-olds, and disc protrusion is found in 20 and 30% of the two groups respectively [65, 66].
Pain is managed by non-steroidal anti-inflammatory drugs, analgesics and muscle relaxants as appropriate to the severity of pain [67]. The patient is reassessed at 710 days and referred for physical therapy, i.e. manipulation, if failing to improve [1, 20]. If the patient is not improving on review after physical treatment, further specialist assessment is recommended, including the evaluation of psychosocial risk factors [1, 20].
The evidence for further treatment is variable and there is no highly effective treatment for non-specific low back pain. Supervised exercises as a fitness programme are beneficial [68]. Behavioural therapy brings additional benefit [69]. Intensive physical retraining programmes are expensive but reduce sickness payments [70]. Manipulation in chronic back pain lacks convincing evidence and trials are under way [71]. Lumbar supports do not have a role in the primary or secondary prevention of back pain. There is insufficient evidence to recommend a support as a treatment [72]. Traction does not show benefit [73].
Pain relief with medication on a long-term basis is unacceptable to many patients. These medications have side-effects on prolonged use and if patients are to remain as active as possible, they need to understand the use of these drugs [67]. Low-dose tricyclic antidepressants have a role in pain modulation and sleep. They are more effective in nerve root compression [74].
There is some evidence of benefit from transcutaneous electrical nerve stimulation and from steroid injections in tender points, but at present there is no evidence for any beneficial effect of acupuncture on spinal pain [75, 76, 77]. Medical interventions appear to have little effect on work resumption, pain or back function in those who are not working because of back pain [78].
For those who remain incapacitated, there are a variety of pain management programmes that rely on the cognitive behavioural approach by a multidisciplinary team. Overall, they have a positive effect on pain and pain behaviour but a smaller effect on function. They require the patient to be actively engaged in their own management and not seeking other treatments [79, 80].
These programmes are currently used late in the course of symptoms, and as yet the effects of this type of intervention in those early in the back pain episode are not known. Guidelines recommend a multidisciplinary programme before 6 months of work has been missed [1].
The management and treatment of non-specific low back pain remain a challenge. Some treatments are of benefit, and new treatments for degenerative disc are in the early stages of development. Current back pain guidelines promote early activity and treatment, with multidisciplinary management that uses a biopsychosocial model for those patients developing disability as a result of back pain. The practitioners who deliver the back pain service of the future will need to be good communicators, conversant with psychological and social issues and able to engage the patient in their own management.
References
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