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Sciatica and radicular pain

Sciatica is pain radiating down the leg caused by irritation of a spinal nerve root, most often from a disc protrusion. Most episodes settle over weeks to months. Where pain is severe or persistent, image-guided injections can reduce it while natural recovery occurs.

True sciatica is different from back pain. The problem is at the spine, but the pain is felt mainly in the leg — often below the knee — following the territory of the affected nerve, and commonly accompanied by pins and needles, numbness or weakness. The same process in the neck produces arm pain. The distinction matters because leg-dominant and back-dominant pain have different causes and different treatments.

What causes it? Most commonly, a disc protrusion pressing on or inflaming a nerve root. Less often, the passage where the nerve exits the spine has narrowed through age-related change, or the spinal canal itself is narrow. Inflammation around the nerve is a large part of the pain — which is why some people have severe symptoms from a modest-looking protrusion, and others have large protrusions on imaging with no symptoms at all.

Will it get better on its own? Usually, yes. Most nerve root pain improves substantially over six to twelve weeks as inflammation settles and the disc protrusion shrinks — disc material is gradually reabsorbed by the body. This natural history shapes sensible treatment: the first aims are to control pain and keep you moving while recovery happens, and to escalate only if it does not.

When is a scan needed? Not immediately in most cases. Imaging is indicated when symptoms are severe or progressive, when weakness is developing, when the diagnosis is uncertain, or when a procedure or surgery is being considered and the exact level must be confirmed. Scans are interpreted alongside your examination — changes at several levels are common, and identifying which one is responsible sometimes requires a diagnostic injection.

How can injections help? An epidural injection places anti-inflammatory medication into the space around the irritated nerve, and a transforaminal injection delivers it selectively to a single nerve root. Both can reduce pain for weeks to months while natural recovery continues — most useful in the earlier phase, when inflammation dominates. A selective injection also has a diagnostic role: if numbing one nerve root abolishes your leg pain, that nerve is confirmed as the source, which matters if surgery is being contemplated on ambiguous imaging.

When is surgery the right answer? When there is significant or progressive weakness, when pain remains severe despite good non-surgical care, or in the rare emergency of cauda equina syndrome. For pain alone, surgery and continued non-surgical care often reach similar positions by a year — surgery tends to get there faster, at the cost of an operation. Where surgery is appropriate, Dr Martin will refer you with the level confirmed.

Warning signs. Numbness around the buttocks or genitals, difficulty passing urine, loss of bowel control, or rapidly worsening leg weakness can indicate cauda equina syndrome, which needs emergency surgery. Do not wait for an appointment — call 000 or go straight to an emergency department.

Sources: Healthdirect Australia; Australian Commission on Safety and Quality in Health Care — Low Back Pain Clinical Care Standard.