Sciatica and disc herniation: pain down the leg

What it is, in plain words

Between each pair of vertebrae sits a disc with a soft centre. If the outer ring tears, that centre can bulge and press on a nerve root leaving the spine. The nerve becomes inflamed and sends pain, numbness or weakness along its territory, typically down the buttock, back of the thigh and into the calf or foot.

Signs to look out for

• Sharp or burning pain radiating below the knee, usually in one leg
• Pain worse on coughing, sneezing, sitting or bending forward
• Pins and needles or numbness in a specific band of the leg or foot
• Weakness such as difficulty lifting the foot or standing on tiptoe
• Back pain that may be milder than the leg pain

Why it happens

Discs weaken with age, and herniation peaks between 30 and 50. Heavy lifting with poor technique, prolonged sitting, smoking, obesity and previous episodes increase risk.

How doctors confirm it

Diagnosis is clinical, using the straight leg raise and a map of sensation, power and reflexes. Imaging is not needed in the first six weeks unless there are red flags, because MRI shows disc bulges in many people without symptoms.

Treatments and solutions

• Staying active within pain limits, since bed rest beyond a couple of days slows recovery
• Regular paracetamol and anti-inflammatory medicine, with neuropathic agents used selectively and with modest evidence
• Physiotherapy with graded exercise and education, started early
• A nerve root corticosteroid injection for severe persistent radicular pain
• Microdiscectomy when disabling pain persists beyond six to twelve weeks, or immediately for significant progressive weakness

Living with it day to day

Around nine in ten people improve substantially within eight weeks. Rebuild core and hip strength, learn to hinge from the hips when lifting, and change posture every 30 minutes at a desk.

When to seek medical help

Go to hospital immediately for numbness around the genitals or inner thighs, loss of bladder or bowel control, or weakness in both legs, which can signal cauda equina syndrome.

This article explains general health information in simple language. It does not replace advice from your own doctor.