Sciatica

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What is Sciatica?

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Sciatica is a term used to commonly describe pain that radiates from the lower back or buttock down the leg. It is usually caused by irritation or compression of one of the nerve roots in the lower spine, most commonly due to a slipped (herniated) disc or age-related wear and tear.

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Symptoms may include:

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• Sharp, burning, or shooting pain down the leg

• Numbness or tingling in the leg or foot

• Muscle weakness

• Pain that is worse when coughing, sneezing, or sitting

• Difficulty walking or standing for prolonged periods

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Symptoms typically affect one side, although both legs can occasionally be involved.

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Why Have I Been Referred for Nerve Conduction Studies (NCS) and Electromyography (EMG)?

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Your doctor may have recommended these tests to:

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• Confirm whether your symptoms are due to a pinched nerve in the lower back

• Identify which nerve root is affected

• Assess whether there is evidence of nerve damage

• Exclude other conditions such as peripheral neuropathy or peroneal nerve palsy

• Help guide treatment decisions

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Although MRI scans show the structure of the spine, they do not always indicate whether a nerve is functioning normally. EMG provides important additional information about nerve and muscle function.

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What to Expect During the Test

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Nerve Conduction Studies (NCS): Small electrodes are placed on the skin over the leg and foot muscles. Mild electrical pulses are used to assess how well the nerves are conducting signals. These tests are often normal in sciatica, but they are helpful in excluding other nerve disorders.

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Electromyography (EMG): EMG is usually the most informative part of the assessment. A very fine, disposable sterile needle is inserted into selected muscles in the leg, and occasionally the lower back, to look for signs of nerve root irritation or injury. The test may cause mild temporary discomfort but is generally well tolerated.

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For further information on NCS/EMG, please visit our information page here.

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Summary

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Sciatica is a common condition caused by irritation or compression of a nerve in the lower back. It can result in pain, numbness, or weakness in the leg. NCS and EMG are safe, specialised tests that help confirm the diagnosis, identify the affected nerve, and exclude other causes of your symptoms. The results assist in determining the most appropriate treatment, which may include physiotherapy, medication, injections, or surgery.