Spinal stenosis

Spinal stenosis is where your spinal canal narrows causing the nerve tissue nearby to compress and inflame. This compression can also reduce the blood supply to your nerves. Spinal stenosis is also called myelopathy and can affect more than one level of your spine. 

Your spine — also called your spinal column — is made of a series of bones stacked on top of each other (vertebrae). In between each vertebra are rubber-like cushions called intervertebral discs, which allow your spine to be flexible. These discs have a strong, fibrous outer part and a softer, jelly-like inner part (nucleus pulposus). 

Running through your spinal column is a space called the spinal canal, which contains your spinal cord — a bundle of nerves that connect your body with your brain. If the spinal canal becomes too narrow, eg due to a slipped vertebra, it can compress the nerves inside.

This nerve compression causes pain, sciatica, numbness and weakness, especially when walking or standing for a long time. Depending on where the spinal stenosis occurs, it can cause:

• Pain and weakness in one or both legs — this happens when the stenosis affects the spinal canal in your lower back 
• Pain and weakness in your shoulders and arms — this happens when the stenosis affects the spinal canal in your neck
• Cauda equina syndrome with symptoms including back pain, bowel and bladder problems, numbness in your buttocks, inner thighs, anal and genital area, and pain and weakness in one or both legs — this happens when the stenosis affects the spinal canal in your lower back, specifically compressing a part of your spinal cord called the conus medullaris

Spinal stenosis is most common in the over 60s. This is due to natural wear and tear of your bones and tissues in the spine, known as osteoarthritis.

Treatment depends on how bad your symptoms are and the location of the stenosis. Simple treatments include anti-inflammatory drugs, painkillers, staying active and losing weight if you're overweight. If these treatments do not work, steroid injections or surgery may be needed.

Spinal stenosis symptoms usually start gradually and include:

• Back pain
• Leg pain or arm pain
• Numbness, tingling and weakness in your limbs

Where you feel symptoms depends on where your spinal canal is narrowed:

• Cervical spinal stenosis — the narrowing occurs in your neck, affecting your shoulders, arms and hands
• Lumbar spinal stenosis — the narrowing occurs in your lower back, causing pain and numbness in your buttocks and down your legs

It's common to experience unsteadiness when you walk due to weakness in one or both of your legs. Weakness and pain in your legs that gets worse as you walk is called claudication — this can be caused by either narrowing of blood vessels that supply your legs or spinal stenosis. 

You may only be able to cover a short distance before needing to rest due to claudication. This is because your spinal column is naturally more constricted while standing. Symptoms may be relieved by leaning forward and usually at rest, the pain stops. Unlike leg pain, back pain caused by spinal stenosis does not usually get worse when walking. 

You should see your GP if you have symptoms that don’t go away after a few days.

If your GP suspects you have spinal stenosis, they'll probably send you to an orthopaedic consultant (specialising in bones and joints).

Your consultant will recommend one or more of these tests to diagnose and rule out other conditions:

• A CT scan
• An MRI scan
• An X-ray

Spinal stenosis is common in older people but in rare cases can affect younger people. It usually affects the lower (lumbar) spine but can also affect the spine in your neck (cervical) and less commonly the spine in your chest (thoracic).

The most common causes of spinal stenosis causes are:

• Injury — dislodged bone from a fracture may damage the spinal canal
• Overgrowth of bone into the spinal canal and thickening of the ligaments that bulge into the spinal canal — both are due to natural wear and tear as you age (osteoporosis)
• Slipped disc — where one of the soft discs between your vertebrae becomes damaged
• Spondylolisthesis — where one of your vertebrae has slipped out of position

In rare cases, spinal stenosis can be caused by a tumour or sometimes people are born with a narrow spine (congenital stenosis). 

Imaging of your spine can help determine the cause of your spinal stenosis. 

In rare cases, severe spinal stenosis that is left untreated can cause permanent:

• Balance problems
• Incontinence
• Numbness
• Paralysis
• Weakness

Your doctor will first use non-invasive or minimally invasive measures to help improve your symptoms. These include:

• Anti-inflammatory medication (eg aspirin or ibuprofen)
• Pain relief
• Physiotherapy exercises to reduce symptoms
• Steroid injections to relieve pain and inflammation in the spine

Spinal decompression surgery may be recommended for severe cases or when other treatments are unsuccessful. This is where the bone compressing your nerves is removed. Spinal fusion may also be carried out, where two of your vertebrae are fused together. The success of the surgery varies — soon after surgery, the results can be good but over time symptoms often return. 

A less invasive procedure called interspinous distraction may be recommended to reduce or prevent pain in your legs while standing or walking. This is where an implant is placed between the bony projections of your vertebra that extend towards your back (spinous processes) — this reduces the extension of your back.

You can also try managing your own symptoms by:  

• Losing weight if you are overweight 
• Staying active — try to gradually increase how much you walk 
• Taking over-the-counter painkillers 
• Taking prescribed medications to ease nerve pain in your legs (eg amitriptyline, gabapentin or pregabalin)

Outcomes vary, but without treatment symptoms usually worsen. Treatments do not offer a cure but can be effective at reducing your symptoms.