What is sciatica?

Sciatica is a general term referring to pain that occurs along the sciatic nerve. The sciatic nerve is the largest nerve in the body (about the width of a finger) and starts in the lower spine. It divides and passes behind each hip, down the buttock and back of each leg to the foot and finally to the big toe. Sciatic pain can be felt anywhere along the pathway of this nerve.

There are many causes for this type of pain, which may be very different in character from back pain (although this may also be present).

Sciatica and related back problems do tend to run in families.

What are the symptoms of sciatica?

Sciatica usually affects only one side of the body, although low back pain may be present at the same time. The pain radiates down the nerve, often to the buttock or leg. It can range in severity from a tingling feeling to severe, shooting pain which makes standing up nearly impossible. The leg or foot may be numb or weak and there may be an inability to move the foot or bend the knee. In severe cases bladder or bowel function may be affected.

Anything which causes the nerve to be stretched can produce pain. Coughing, sneezing and sitting all make the pain worse.

Sciatica often lasts for six weeks or more.

What are the causes of sciatica?

Sciatica may be caused by the sciatic nerve becoming pinched between the vertebrae of the spine. It may also arise if the space in which the nerve lies becomes narrowed by arthritis or by swelling due to a sprain in the area. Very rarely, a blood clot, abscess or growth may push on the nerve, causing sciatica.

A common cause of sciatica is a prolapsed lumbar disc. The prolapsed disc may bulge into the vertebral canal and compress the nerve roots. This may happen as a result of poor lifting technique or lifting something too heavy. Digging the garden or other forms of strenuous exercise may also put pressure on a disc. The pain may begin as mild attacks of back pain and the back may become slowly more stiff and painful or, as is more usually the case, it may start as a sudden severe pain across the back that radiates down one side.

Diagnosis and investigations

Physical examination may be all that is necessary to make the diagnosis. X-rays are often not very helpful. A computerised tomographic (CT) scan or a magnetic resonance imaging (MRI) scan may be necessary to diagnose the cause of the sciatica, especially if there are complications or if symptoms are slow to resolve.

What treatment is available?

For severe sciatica the initial treatment is rest. This should be on a firm mattress or on the floor. Sitting or lying in the bath should be avoided as this will make the pain worse. Complete rest will be advised for the first few days followed by very short periods of moving around, with avoidance of any bending or lifting.

Analgesics (painkillers) are usually prescribed for sciatica. They do not cure the condition but relieve the pain. They may include aspirin or paracetamol or combination products (eg, paracetamol and codeine).

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen may be prescribed to reduce pain and swelling caused by inflammation.

Topical NSAIDs in the form of gels and creams may be applied directly to the lower back. Most of these are available without prescription.

Topical creams which also cause a feeling of warmth are available. These may contain analgesics such as salicylates. Some of these are available only on prescription.

Muscle relaxants such as diazepam can help relieve muscle spasm, which often aggravates the pain.

Physiotherapy will not be of use until the pain has receded, which may take four to six weeks. After this time, a physiotherapist can teach exercises to strengthen the back in order to prevent further episodes of sciatica.

If the sciatica does not resolve with bed rest and medication after six weeks, further investigations may reveal the need for surgical treatment. This may involve removal or repair of a disc or part of a vertebra.

Self-help measures:

  • Unfortunately, sciatica tends to recur. Once an episode of sciatica has happened, take care to avoid further injury to the back.
  • Practise exercises as recommended by a physiotherapist on a permanent basis. Swimming and walking also help to strengthen the muscles of the back.
  • Avoid sitting for long periods, take regular breaks on long journeys.

Further information available from: 

BackCare (The Charity for Back and Neck Pain) 
16 Elm Tree Road
TW11 8ST
Tel: 020 8977 5474
Helpline: 0845 130 2704

Fact sheet provided by MIMS

Date last reviewed: September 2014

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