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Lewis R, Williams N, Matar HE, et al. The Clinical Effectiveness and Cost-Effectiveness of Management Strategies for Sciatica: Systematic Review and Economic Model. Southampton (UK): NIHR Journals Library; 2011 Nov. (Health Technology Assessment, No. 15.39.)

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The Clinical Effectiveness and Cost-Effectiveness of Management Strategies for Sciatica: Systematic Review and Economic Model.

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3Background

Definition of sciatica

Sciatica is a symptom defined as unilateral, well-localised leg pain with a sharp, shooting or burning quality that approximates to the dermatomal distribution of the sciatic nerve down the posterior lateral aspect of the leg, and normally radiates to the foot or ankle. It is often associated with numbness or paraesthesia in the same distribution.1,2 The symptom of sciatica is used by clinicians in different ways. Some refer to any leg pain referred from the back as sciatica, others prefer to restrict its use to pain originating from the lumbar nerve root. Some authors prefer to use the term ‘lumbar nerve root pain’ to distinguish it from referred leg pain.3

Epidemiology of sciatica

The lack of clarity in the definition of sciatica persists in the epidemiological literature. In the UK, the prevalence of ‘sciatica suggesting a herniated lumbar disc’ has been reported as 3.1% in men and 1.3% in women.4 However, like most surveys, this study did not use strict criteria to diagnose sciatica. A large population survey in Finland which did found a lifetime prevalence of 5.3% in men and 3.7% in women.5 Sciatica accounts for < 5% of the cases of lower back pain presenting to primary care.3 Some cohort studies have found that most cases resolve spontaneously, with 30% of patients experiencing persistent troublesome symptoms at 1 year, 20% out of work and 5–15% requiring surgery.6,7 However, another cohort found that 55% still had symptoms of sciatica 2 years later, and 53% after 4 years (which included 25% who had recovered after 2 years, but had relapsed again by 4 years).8 As the sciatica becomes more chronic (> 12 weeks), or with recurrent episodes, it becomes less responsive to treatment.9 Effective treatment for patients with acute or subacute sciatica is therefore important in order to prevent patients developing a more chronic condition that is resistant to treatment and likely to incur high health-care and socioeconomic costs. The cost of sciatica to society in the Netherlands in 1991 was estimated at US$128M for hospital care, US$730M for absenteeism and US$708M for disablement.10

Pathological mechanism

Sciatica caused by lumbar nerve root pain usually arises from a prolapsed intervertebral disc, but also from spinal stenosis, or surgical scarring as well as other aetiologies such as trauma and tumours.6 It was initially thought to occur predominantly as a result of compression of the nerve root,11 leading to neural ischaemia, oedema (which would, in turn, lead to chronic inflammation), scarring and perineural fibrosis. However, it is now known that symptoms can occur in the absence of direct nerve root compression, possibly as a result of release of proinflammatory factors from the damaged disc. Pain occurs because of chronic, repetitive firing of the inflamed nerve root.12,13 Referred leg pain occurs because pain fibres from paraspinal structures and from the leg converge on interneurons in the spinal cord and brain, so that nociceptive input from painful paraspinal tissues is perceived as leg pain.

Clinical diagnosis

It has been claimed that nerve root pain can be distinguished from referred leg pain because it is unilateral, radiates below the knee, results in leg pain that is worse than the back pain, can be aggravated by coughing or sneezing and has a segmental distribution. Important clinical signs include provocation tests for dural irritation, such as a limited straight leg raise (SLR) reproducing the leg pain, and compromised nerve root function leading to reduced power, sensation or reflexes in one nerve root.3 A systematic review of the diagnostic value of history and physical examination in nerve root pain found that pain distribution was the only useful item in the history. The SLR test was the only sensitive sign in the physical examination, but had poor specificity; the crossed SLR test was the only specific sign, but had poor sensitivity.14 However, another review found that there was no standard SLR procedure, no consensus on interpretation of results, no evidence of intra- and inter-observer reliability and its predictive value in lumbar intervertebral disc surgery was unknown.15

Treatments

A variety of surgical and non-surgical treatments have been used to treat sciatica and have been the subject of previous systematic reviews, the findings of which are summarised below. However, none of the reviews examined the cost-effectiveness of the various treatment modalities.

Bed rest and advice to stay active

Most cases resolve spontaneously and, traditionally, bed rest has been advised. A Cochrane systematic review of bed rest16 found that there was high-quality evidence of little or no difference in pain or functional status between bed rest and staying active; moderate-quality evidence of little or no difference in pain intensity between bed rest and physiotherapy, but small improvements in functional status with physiotherapy; and moderate-quality evidence of little or no difference in pain intensity or functional status between 2–3 and 7 days' bed rest. A Cochrane systematic review of advice to keep active reviewed the same trials comparing bed rest with activity and came to the same conclusions. Although there is no evidence to advise bed rest for sciatica, there is also very little evidence of any benefit of keeping active.16

Analgesia

Most patients will obtain analgesic medication either on prescription or purchased ‘over the counter’ from their pharmacist. A systematic review of the conservative treatment for sciatica identified three randomised controlled trials (RCTs) that compared non-steroidal anti-inflammatory drugs (NSAIDs) with a placebo tablet and found no evidence of efficacy.17

Intramuscular steroids

Part of the mechanism of production of nerve root pain is the release of proinflammatory factors from damaged discs, so administration of intramuscular corticosteroid steroid injections to reduce inflammation of the nerve root has a theoretical basis. The systematic review of conservative treatment for sciatica identified two RCTs comparing steroid injections with a placebo injection and found no evidence of efficacy.17

Traction

Traction is used relatively frequently to treat sciatica in North America, but less frequently in the UK, Ireland and the Netherlands.18,19 A Cochrane systematic review found strong evidence that there was no significant difference between either continuous or intermittent traction versus placebo, sham or other treatments.20

Epidural steroids

Introduction of corticosteroids into the epidural space is a commonly used treatment for lumbar nerve root pain, with the rationale of reducing nerve root inflammation. It was performed on 47,665 occasions in the NHS in England in 2005–6.21 Systematic reviews of ESIs have reached conflicting conclusions with regard to their efficacy compared with placebo and their effectiveness compared with other treatments.17,22–24

Spinal manipulation

The systematic review of conservative treatment for sciatica identified two RCTs of spinal manipulation. One found that manipulation was more effective than placebo, and another found no difference compared with manual traction, exercises or corset.17

Chemonucleolysis

Chemonucleolysis is a technique that is now rarely used. It attempts to decrease the volume of a disc herniation by reducing the amount of material contained within the nucleus pulposus by injecting the enzyme chymopapain. A systematic review of lumbar discectomy and percutaneous treatments identified three RCTs that compared chymopapain with placebo injection, and reported that symptom relief was greater in the group that received chymopapain.25

Lumbar discectomy

Between 5% and 15% of patients with lumbar nerve root pain are treated with surgery,6,7 usually involving a lumbar discectomy. In 2005–6, 8683 lumbar discectomies were performed in the NHS in England.21 A Cochrane systematic review of surgery for lumbar disc prolapse26 found 40 RCTs and two quasi-randomised controlled trials (Q-RCTs), but only four RCTs comparing discectomy with conservative management, which suggested a temporary benefit in clinical outcomes at 1 year, but no difference at longer-term follow-up. Meta-analyses showed that surgical discectomy produced better clinical outcomes than chemonucleolysis, which was better than placebo. The review concluded that there was considerable evidence of the clinical effectiveness of discectomy for carefully selected patients with sciatica caused by lumbar disc prolapse that fails to resolve with conservative management. Serious complications from lumbar disc surgery are uncommon, with one study25 reporting a mortality rate of 0.3% an infection rate of 3% and 4% requiring an intraoperative transfusion. Surgery failed to relieve symptoms in 10–20% of the cases.25

Other treatments

A number of other treatments that have not been included in previous systematic reviews, for example complementary therapies such as acupuncture, will be included in this review.

Pattern of treatments

Overall, there is no close correlation between symptom severity and pathology in sciatica. Increasing distance between onset and effective treatment has an unfavourable influence on symptoms and disability. Although there is reason to suppose that a stepped-care approach to sciatica could be helpful, the application of the various available treatments depends more on availability, clinician preference and socioeconomic variables than on patient needs. In practice, some patients will recover under an analgesic cocktail while on a waiting list, some will be offered surgery as a first-line intervention, and yet others will receive a combination of treatments in no particular order. With few exceptions, it would appear that the patients receiving differing treatments are clinically indistinguishable.

© 2011, Crown Copyright.

Included under terms of UK Non-commercial Government License.

Bookshelf ID: NBK99305
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