Sciatica is common and although it often resolves in a few weeks with self-help measures, symptoms can be severe or unresponsive and patients may need pharmacological or surgical intervention, writes Steve Titmarsh…

Sciatica is the term used to describe pain that may begin in the lower back and it runs down the back of the leg to the foot on one side only, in other words the length of the sciatic nerve. It is a common condition and can range in severity from mild to severe.^1,2

Sciatica is caused by compression or irritation/inflammation of the sciatic nerve at the bottom part of the spine, for example from a disc prolapse (‘slipped disc’).³ Other causes include: spondylolisthesis where a vertebra slips forward, and spinal stenosis where narrowing of the spinal canals (structures that protect nerves in the spine) causes pain that is relieved by sitting and leaning forward and made worse by standing and stretching the spine. Rarely the cause may be infection or cancer.²

Sciatica most often affects people around 40 years of age and rarely before 20 years of age unless there has been some other trauma from physical activity, for example, or from prolonged periods of time adopting a poor posture such as might happen at work, for example.³ Around 13–40% of people will experience sciatica at some point in their lives.²

The risk of sciatica developing is associated with modifiable factors such as smoking, obesity and occupational factors such as driving or operating machinery or strenuous activity such as frequent heavy lifting, especially while bending and twisting. Other factors include age and genetic influences.²

Symptoms

Damage to the sciatic nerve results in a range of symptoms, including a change in sensation in the foot or leg, muscle spasms in the back, weakness in the leg or foot.¹ People often experience tenderness with pressure, muscle weakness and pain that is worse with movement.³ A change in feeling in the leg or foot can manifest as pins and needles, numbness, hot or cold, burning sensations, shooting sensations or other feelings that can be difficult to put into words.¹

Symptoms can appear suddenly or over a period of time.²

Diagnosis

People with sciatica may experience low back pain but the pain from sciatica is usually more severe than that from low back pain per se and is usually felt at the back of the leg and below the knee, but on one side only.³And sciatica differs from muscle pain or spasm, which can range from a minor twitch to painful contractions. Indeed, muscle spasm can increase the risk of sciatica.⁴

Formal medical assessment involves a focussed musculoskeletal and neurological work up, including: examining the spine for deformity and tenderness; observing gait, ability to walk and pain behaviour; assessing the passive range of motion in the spine and hips; assessing for neurological signs such as numbness, paraesthesia, muscle weakness, or loss of tendon reflexes. A straight leg raising test, extensor plantar response and femoral stretch or contralateral femoral stretch test may also be undertaken.²

A spinal X-ray is not routinely recommended to confirm the diagnosis. If infection, malignancy or inflammation are suspected as the cause then investigations such as full blood count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), blood cultures, or urinalysis and culture may be warranted.²

Diagnoses that may be considered other than sciatica include:²

• Neurological disorders, eg myelopathy or higher cord lesion, peroneal palsy or other neuropathies, deep gluteal syndrome/piriformis syndrome, spinal stenosis
• Systemic disorders, eg metastatic neoplasm, sacroiliitis in ankylosing spondylitis and other spondyloarthropathies, vascular claudication
• Other conditions, eg abdominal aortic aneurysm, aseptic necrosis of the femoral head, facet arthropathy, greater trochanteric pain syndrome, Herpes zoster, osteoarthritis of the hip, pancreatitis, pelvic inflammatory disease, pelvic mass, prostatitis, pyelonephritis.

Self-care measures

The STarT Back screening tool, which can be found at https://startback.hfac.keele.ac.uk, can be useful to assess risk and provide a basis for shared decision making about management. Aimed at primary care clinicians managing people with back pain the website also provides information for patients.^2,5

People with sciatica should be encouraged to stay active and resume normal activities as soon as possible: prolonged bed rest is not recommended. Exercises such as swimming, yoga and Pilates can be beneficial. More information is available from numerous sources, including Backcare’s website – www.backcare.org.uk.^2,5

Sciatica spontaneously improves within six weeks in half of those affected, and most people’s symptoms improve over time with conservative treatment or surgery. However, recurrence is common.²

Other treatment options

People with a higher risk of poor outcomes might benefit from group exercise programmes (biomechanical, aerobic, mind–body, or a combination of approaches), manual therapy from a physiotherapist or psychological therapy.^2,5

Poorer outcomes are seen in people who have had time off work, have problems or dissatisfaction at work, are involved in heavy work, or working unsociable hours. People with low or negative mood, stress, overprotective family, lack of support, social withdrawal and beliefs such as that the problem will last a long time or inappropriate expectations of treatment are also likely to experience poorer outcomes.²

Analgesia can be considered to manage symptoms of low back pain. However, nonsteroidal anti-inflammatory drugs (NSAIDs) have limited benefit for people with sciatica. If used they should be taken in the lowest effective dosage for the shortest possible time. There is no evidence of overall benefit from gabapentinoids, other antiepileptics, oral corticosteroids, or benzodiazepines, but there are risks associated with taking these drugs so people with sciatica already taking them should consider a managed withdrawal.²

People whose sciatica does not respond to self-help or pharmacological options may benefit from surgery such as spinal decompression.⁶ In cases of acute and severe sciatica an epidural corticosteroid/local anaesthetic injection may help.²

When to seek medical attention

People whose symptoms do not improve or become worse should be referred for medical assessment.⁶

People with sciatica should be referred for urgent medical attention if they have:^2,6

• Bowel/bladder dysfunction (most commonly urinary retention).
• Progressive neurological weakness
• Loss of sensation around the buttocks, perineum and inner thighs only (saddle anaesthesia)
• Pain, numbness or tingling that affects both legs (bilateral radiculopathy)
• Incapacitating pain
• Unrelenting night pain
• Use of steroids or intravenous drugs.

References

1. NHSinform. Sciatica (www.nhsinform.scot/illnesses-and-conditions/muscle-bone-and-joints/conditions/sciatica; accessed April 2023).
2. Clinical Knowledge Summaries. Sciatica (https://cks.nice.org.uk/topics/sciatica-lumbar-radiculopathy/background-information/definition; accessed April 2023.)
3. Fairag M, Kurdi R, Alkathiry A, et al. Risk Factors, Prevention, and Primary and Secondary Management of Sciatica: An Updated Overview. Cureus 2022;14(11):e31405.
4. Advanced Bone & Joint. Is It Sciatica or Muscle Spasms? (www.advancedboneandjoint.com/is-it-sciatica-or-muscle-spasms; accessed April 2023).
5. National Institute for Health and Care Excellence (NICE). Low back pain and sciatica in over 16s: assessment and management. NICE guideline [NG59]. London: NICE, 2016.
6. NHS.UK. Sciatica (www.nhs.uk/conditions/sciatica; accessed April 2023).