Lumbar Disc Herniation

What is it?

Between the vertebrae sit discs that absorb shock and keep the spine flexible. Each disc has a tough outer ring and a gel-like centre. A lumbar disc herniation happens when some of this centre pushes out through a tear in the outer ring and presses on, or chemically irritates, a nearby nerve root.

Most herniations occur low in the spine, at the L4-L5 and L5-S1 levels. When a nerve root is affected, the pain does not stay in the back: it can travel along the nerve into the buttock, leg and foot. This radiating pain is called radiculopathy (pain arising from a nerve root) and is often described as sciatica.

What causes it?

A herniation rarely results from a single event. More often it reflects wear that has built up in the disc over years. With age, discs lose water and elasticity and the outer ring becomes more vulnerable; against this background, lifting something heavy or twisting suddenly can trigger symptoms.

Factors that increase the risk include:

• Age-related disc degeneration and a family history of disc problems
• Heavy lifting, frequent bending or exposure to vibration at work
• Long periods of sitting without moving
• Excess weight and weak trunk muscles
• Smoking

Seeing a herniation on an MRI does not automatically mean it is causing the pain, because disc bulges are common in people with no symptoms at all. What matters is whether the scan findings match the person's symptoms and examination.

How is it diagnosed?

Diagnosis begins with a history and a neurological examination. Where the pain travels, where sensation is reduced, and changes in muscle strength and reflexes all point to which nerve root is involved. Tests such as raising the straightened leg while you lie on your back can reveal tension on the nerve root.

MRI shows the location and size of the herniation, and its relationship to the nerves, in more detail than any other test. Without warning signs it is usually not needed in the first few weeks; it is requested if symptoms persist, there is weakness, or an interventional treatment is being considered. In some people, EMG (a test of the electrical activity of nerves and muscles) helps assess the extent of nerve involvement.

Treatment options

Symptoms from a lumbar disc herniation ease within a few weeks to a few months in many people, and some herniations are known to shrink over time. For this reason, treatment usually starts without surgery.

Conservative care

• Staying active: apart from a short rest, bed rest is not advised. Walking and continuing daily activities as far as the pain allows is helpful.
• Exercise and physiotherapy: as the pain settles, programmes that strengthen the trunk and support the mobility of the nerve are introduced.
• Medication: short courses of anti-inflammatory painkillers can help. Some medicines used for nerve pain offer limited benefit in this situation, so the choice is made individually.

Interventional pain treatments

If pain still significantly limits daily life after several weeks of treatment, interventional options can be considered. An overview of these is given on the non-surgical lumbar disc treatment page:

• Epidural steroid injection: performed under imaging guidance to reduce inflammation and swelling around the nerve root, mainly for severe pain spreading down the leg.
• Nucleoplasty and percutaneous laser disc decompression: aim to reduce pressure inside the disc, which is reached through a fine needle. They may suit only contained herniations in which disc height is preserved, and are not used when a fragment has broken free.
• Radiofrequency treatment: for long-standing nerve root pain, pulsed radiofrequency can be applied next to the affected nerve root at a low temperature that does not damage the tissue.

In suitable patients these treatments can bring a meaningful reduction in pain, but results vary from person to person and each procedure carries its own risks.

When is surgery needed?

Cauda equina syndrome, in which bladder or bowel control is affected, requires emergency surgery. Progressive muscle weakness, or disabling pain that persists despite appropriate treatment, is assessed together with a neurosurgeon or an orthopaedic spine surgeon.

When should you see a doctor?

See a doctor if leg pain is not easing after a few weeks, if numbness or weakness develops, or if pain is stopping you from sleeping or working. An algology (pain medicine) specialist will review your examination alongside your MRI and explain which treatments may suit you; you can request an appointment through our contact page.