Spinal Stenosis

What is it?

Spinal stenosis is a narrowing of the canal that carries the spinal cord and nerve roots, or of the openings (foramina) through which the nerves leave the spine. The narrowing can affect the centre of the canal (central stenosis), its sides (lateral recess stenosis) or the nerve openings (foraminal stenosis).

It is most common in the lower back (lumbar stenosis) and in people over 50. Symptoms usually develop gradually over years and may be felt in both legs. With foraminal narrowing, by contrast, symptoms are often one-sided and resemble sciatica.

Narrowing in the neck can cause symptoms in the arms and, as it progresses, problems with walking and hand dexterity caused by pressure on the spinal cord.

What causes it?

Spinal stenosis is usually the result of age-related changes that develop in the spine over many years:

• Loss of disc height and disc bulging: as discs thin and bulge outwards, the canal becomes narrower.
• Facet joint arthritis: enlarged joints and bony outgrowths (osteophytes) can encroach on the canal.
• Thickened ligaments: thickening of the ligament that forms the back wall of the canal (ligamentum flavum).
• Spondylolisthesis: a vertebra slipping forward can narrow the canal.
• A naturally narrow canal, previous surgery or injury are less common causes.

These changes often occur together and, in the lower back, are most pronounced at the L4-L5 level. Narrowing does not always cause symptoms; some people have marked stenosis on a scan but only mild complaints.

How is it diagnosed?

The typical symptom of stenosis in the lower back is neurogenic claudication: pain, numbness and heaviness in the legs that develop when walking or standing and are relieved by sitting down or leaning forward. Many people notice they can walk further when leaning on a shopping trolley.

Leg pain that comes on with walking can also be caused by narrowed leg arteries (vascular claudication). With circulation problems, simply stopping and standing still usually brings relief, whereas stenosis typically requires sitting down or bending forward. For this reason the pulses in the feet are checked and vascular tests are arranged if needed.

MRI shows the location and degree of narrowing in detail. CT can be used when MRI is not possible, and standing X-rays may be requested to assess the alignment of the spine. EMG can help to show how much the nerve roots are affected and to distinguish conditions that cause similar symptoms, such as diabetic nerve damage.

Treatment options

Spinal stenosis progresses slowly, and in many people symptoms remain stable for long periods. Treatment aims to increase walking distance and improve quality of life.

Conservative care

• Exercise and physiotherapy: exercises performed leaning forward, stationary cycling and trunk-strengthening programmes can support walking capacity.
• Staying active and managing weight: short but frequent walks, resting when needed and gradually increasing the distance.
• Everyday adjustments: sitting down at intervals when you have to stand for long, and using support such as a shopping trolley or a walking stick, can make walking easier.
• Medication: painkillers are planned with age, kidney and stomach health and other individual factors in mind.

Interventional pain treatments

• Epidural steroid injection: may be considered in selected patients with nerve root pain spreading down the leg, particularly when it is caused by foraminal narrowing. Its benefit for walking-related leg pain caused by central canal stenosis is limited, and guidelines advise caution here.
• Radiofrequency treatment: can be used for accompanying facet joint back pain that has been confirmed with a diagnostic block.
• Spinal cord stimulation: may be considered in selected situations that have not responded to other treatments, such as persistent leg pain after spinal surgery, following a successful trial period.

In suitable patients these treatments can provide a meaningful reduction in pain, but they do not remove the narrowing, and the duration of benefit varies from person to person.

When is surgery considered?

If walking distance has become severely limited, weakness is progressing or quality of life remains badly affected despite non-surgical care, surgery to widen the canal (decompression) is assessed with a neurosurgeon or an orthopaedic spine surgeon.

When should you see a doctor?

See a doctor if your walking distance is steadily getting shorter, numbness or weakness in your legs is increasing, or pain is stopping you from managing everyday tasks. An algology (pain medicine) specialist will assess how your symptoms relate to the narrowing and plan the treatment steps with you; you can request an appointment through our contact page.