Sciatica

Sciatica

Sciatica is the name given to any sort of pain that is caused by irritation or compression of the sciatic nerve. The sciatic nerve is the longest nerve in your body. It runs from the back of your pelvis, through your buttocks, and all the way down both legs, ending at your feet.

Signs and symptoms

When the sciatic nerve is compressed or irritated, it can cause pain, numbness and a tingling sensation that radiates from your lower back and travels down one of your legs to your foot and toes.

The pain can range from being mild to very painful, and may be made worse by sneezing, coughing, or sitting for a long period of time. Some people with sciatica may also experience muscle weakness in the affected leg. While people with sciatica can also have general back pain, the pain associated with sciatica usually affects the buttocks and legs much more than the back.

When to see your doctor

Most people find their sciatic pain goes away naturally within a few weeks, although some cases can last for a year or more. You should see your doctor if your symptoms are severe or persistent, or are getting worse over time. Your doctor will usually be able to confirm a diagnosis of sciatica based on your symptoms and recommend suitable treatments. If necessary, they can refer you to a specialist for further investigation.

You should immediately call for an ambulance if you experience loss of sensation between your legs and around your buttocks and/or loss of bladder or bowel control. Although it is rare, these symptoms can be a sign of a serious condition called cauda equina syndrome.

In the vast majority of cases, sciatica is caused by a herniated or "slipped" disc. This is when one of the discs that sit between the bones of the spine (the vertebrae) is damaged and presses on the nerves. Less common causes include spinal stenosis (narrowing of the nerve passages in the spine), a spinal injury or infection, or a growth within the spine (such as a tumour).

You can minimise your risk of developing a slipped disc or back injury that could lead to sciatica by adopting a better posture and lifting techniques at work, as well as stretching before and after exercise, and exercising regularly.

How sciatica is treated

Many cases of sciatica will pass in around six weeks without the need for treatment. However, a combination of things you can do at home – such as taking over-the-counter painkillers, exercising and using hot or cold packs – may help reduce the symptoms until the condition improves.

In more persistent cases, you may be advised to follow a structured exercise programme under the supervision of a physiotherapist, have injections of anti-inflammatory and painkilling medication into your spine, and/or take stronger painkiller tablets. In rare cases, surgery may be needed to correct the problem in your spine.

Causes of sciatica 

Sciatica occurs when the sciatic nerve, which runs from your back to your feet, becomes compressed or irritated. There are many reasons why this may happen, although the vast majority of cases are caused by a herniated or "slipped" disc.

Herniated ('slipped') disc

Your spine is made up of vertebrae, discs and nerves. Vertebrae are the blocks of bone that make up the structure of your spine and protect the nerves.

The vertebrae are supported and cushioned by discs. These discs are made from a tough, fibrous case that contains a softer, gel-like substance. A herniated disc occurs when the outer part of the disc ruptures (splits), allowing the gel inside to bulge and protrude outwards between the vertebrae. When this presses against the sciatic nerve, it can cause sciatica.

It is not always clear what causes a disc to break down, although age is a common factor. As you get older, your spinal discs start to lose their water content, making them less flexible and more likely to rupture – this is sometimes called "degenerative disc disease".

Spinal stenosis

Spinal stenosis is the narrowing of the passage where the spinal cord travels down the spine. It occurs when the ligaments become overgrown, but bulging of spinal discs and bony spurs from the vertebrae can also contribute. The sciatic nerve is only occasionally affected, meaning that the symptoms tend to be pain in a person's lower back, with heaviness of the legs, a stooped posture and difficulty walking.

Spinal stenosis is usually caused by age-related changes in the spine, but can also be down to degenerative disease of the spinal joints, which causes the vertebrae to lose their correct alignment.

Spondylolisthesis

Spondylolisthesis occurs when a vertebra slips out of position. If the slipped vertebra compresses the sciatic nerve, it can cause sciatica. Spondylolisthesis is most commonly caused by age-related or degenerative wear of the spinal joints. However, in younger people, it can be caused by spinal fractures and repeated excessive bending of the spine.

Other causes

Less commonly, sciatica may be caused by:

• an infection in the spine
• an injury to the spine, or the surrounding muscles and ligaments
• a growth within the spine, such as a tumour
• cauda equina syndrome.

Cauda equina syndrome

Cauda equina syndrome is a rare but serious condition that can cause sciatica. The cauda equina is the bundle of nerves that lead out from the end of the spinal cord. Cauda equina syndrome occurs when these nerves are compressed and damaged. 

It can eventually lead to paralysis if left untreated. One of the warning signs of cauda equina syndrome is suddenly losing control of your bladder or bowels. If this happens, you should call for an ambulance immediately.

Preventing sciatica 

It is not always possible to prevent sciatica, but there are several things you can do to help prevent back injuries that could lead to sciatica, such as a herniated or 'slipped' disc.

Lifting and handling

One of the biggest causes of back injury, particularly at work, is lifting or handling objects incorrectly. Learning and following the correct method for lifting and handling objects can help prevent sciatica:

• Think before you lift – can you manage the lift? Are there any handling aids you can use?
• Start in a good position – your feet should be apart, with one leg slightly forward to maintain balance. When lifting, let your legs take the strain – bend your back, knees and hips slightly, but do not stoop or squat. Tighten your stomach muscles. Do not straighten your legs before lifting, as you may strain your back on the way up.
• Keep the load close to your waist – keep the load as close to your body for as long as possible, with the heaviest end nearest to you.
• Avoid twisting your back or leaning sideways – especiallywhen your back is bent. Your shoulders should be level and facing in the same direction as your hips. Turning by moving your feet is better than lifting and twisting at the same time.
• Keep your head up – once you have the load secure look ahead, not down, at the load.
• Know your limits – there is a big difference between what you can lift and what you can safely lift. If in doubt, get help.
• Push, don't pull – if you have to move a heavy object across the floor, it's better to push rather than pull it.
• Distribute the weight evenly – if you are carrying shopping bags or luggage, try to distribute the weight evenly on both sides of your body.

Posture

How you sit, stand and lie down can also have an important effect on your back. The following tips should help you maintain a good posture:

Standing

Stand upright, with your head facing forward and your back straight. Balance your weight evenly on both feet, and keep your legs straight.

Sitting

You should be able sit upright, with support in the small of your back. Your knees and hips should be level, and your feet should be flat on the floor (use a footstool if necessary). Some people find it useful to use a small cushion or rolled-up towel to support the small of the back.

If you use a keyboard, make sure that your forearms are horizontal and your elbows are at right angles.

Driving

Make sure that your lower back is properly supported. Correctly positioning your wing mirrors will prevent you from having to twist around. Foot controls should be squarely in front of your feet. If driving long distances, take regular breaks so that you can stretch your legs.

Sleeping

Your mattress should be firm enough to support your body while supporting the weight of your shoulders and buttocks, keeping your spine straight. If your mattress is too soft, place a firm board under the mattress. Support your head with a pillow, but make sure that your neck is not forced up at a steep angle.

Exercise

Regular exercise can help reduce your risk of developing a herniated disc by slowing down the age-related deterioration of the discs in your back. It can also help keep your supporting back muscles strong and supple. You should warm up and cool down properly before and after any workout or sports activity. Your warm up and cool down should incorporate stretching exercises.

Diagnosing sciatica 

Your doctor will usually be able to confirm a diagnosis of sciatica based on your symptoms. They will ask you what symptoms you experience, and which parts of your body are affected. Sciatica typically causes pain, numbness and a tingling sensation that radiates from the lower back and down one leg. Any pain in your lower back will generally be less severe than the pain in the affected leg.

A simple test known as the "passive straight leg raise test" can also help your doctor identify whether you have sciatica. This test involves lying flat on your back with your legs straight, and lifting one leg at a time. If lifting one of your legs causes pain or makes your symptoms worse, it is usually an indication that you have sciatica.

Warning signs

During your appointment, your doctor will also ask you questions about anything in your medical history and individual circumstances that could indicate a potentially more serious cause of your symptoms, such as cauda equina syndrome, an infection of the spine, a spinal fracture, or cancer. Family doctors refer to these warning signs as "red flags".

Red flags that suggest cauda equina syndrome include:

• tingling or numbness between your legs and around your buttocks
• recent loss of bladder and/or bowel control
• weakness in your leg and foot.

Red flags that suggest cancer or infection include:

• being over 50 or under 20 years of age
• a history of cancer
• symptoms of fever, chills or unexplained weight loss
• having had a recent bacterial infection, such as a urinary tract infection (UTI)
• having a history of injecting illegal drugs, such as heroin or cocaine
• having a condition that weakens your immune system, such as HIV
• a structural deformity of the spine.

Red flags that suggest a spinal fracture include:

• sudden severe pain in the spine which is relieved by lying down
• recent major trauma, such as a road accident or fall from a height
• minor trauma, including strenuous lifting in people with osteoporosis (weakened bones)
• a structural deformity of the spine.

Having one or more of these warning signs does not necessarily mean you have a serious condition, but it does mean a potentially more serious cause should be considered and investigated. Therefore, if you have any red flags, your doctor will probably refer you for further tests. If you have any warning signs that suggest cauda equina, they will make sure you are admitted to hospital immediately.

Further tests

Further tests are not usually necessary, unless a potentially serious cause of your symptoms is suspected. In such cases, you may have a blood test to rule out infections and/or scans, such as a computerised tomography (CT) scan or a magnetic resonance imaging (MRI) scan to detect any problems with the nerves and structure of your spine. Scans may also be carried out to examine your spine if surgery is being considered as a treatment option.

Treating sciatica 

Treatment for sciatica is not always necessary, as the condition often improves naturally within around six weeks. However, if your symptoms are severe or persistent, a number of treatments are available. These usually include self-help and conservative treatments, such as medication and physiotherapy, although it's not clear exactly how effective many of these treatments are in treating sciatica. In a small number of cases, surgery may be recommended to correct the problem in your spine that is thought to be causing your symptoms.

Self-help

There are a number of things you can do yourself to help reduce troublesome sciatica symptoms. These include remaining as active as possible, using hot or cold compresses, and taking simple painkillers, such as paracetamol or ibuprofen.

Exercise

If you have sciatica, it is important for you to remain as physically active as possible. Simple exercises, such as walking and gentle stretching, can help reduce the severity of your symptoms and strengthen the muscles that support your back.

While bed rest may provide some temporary pain relief, prolonged bed rest is often considered unnecessary and unhelpful. If you have had to take time off work due to sciatica, you should aim to return to work as soon as possible.

Compression packs

Some people find that using either hot or cold compression packs on painful areas can help to reduce the pain. You can make your own cold compression pack by wrapping a pack of frozen peas in a towel. Hot compression packs are usually available from pharmacies. You may find it effective to use one type of pack followed by the other.

Painkillers

If you have persistent or troublesome sciatic pain, there are a number of painkilling medications that may help. These include:

• paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen
• opioid medication, such as codeine or, in severe cases, morphine
• tricyclic antidepressants (TCAs), such as amitriptyline – these medications were originally designed to treat depression, but they have since been found to help relieve nerve pain
• anticonvulsants, such as gabapentin – these medications were originally designed to treat epilepsy but, like TCAs, they can also be useful for treating nerve pain.

These medications are not suitable for everyone, particularly when used in the long term, so it's important to discuss all available options with your doctor. Some of these medications can also cause significant side effects in some people. If the painkilling medications your doctor prescribes do not help, you may be referred to a specialist pain clinic for further treatment.

Spinal injections

If other methods of pain relief have not worked, your doctor may refer you to a specialist for a spinal corticosteroid and/or local anaesthetic injection. This delivers strong anti-inflammatory and painkilling medication directly to the inflamed area around the nerves of your spine, which may help release the pressure on your sciatic nerve and temporarily reduce your pain.

Physiotherapy

In some cases, your doctor may recommend a suitable exercise plan for you, or they may refer you to a physiotherapist. A physiotherapist can teach you a range of exercises that strengthen the muscles that support your back and improve the flexibility of your spine. They can also teach you how to improve your posture and reduce any future strain on your back.

Surgery

Surgery is rarely necessary to treat sciatica, although it may be considered if the condition has an identifiable cause, such as a herniated or "slipped" disc, the symptoms have not responded to other forms of treatment, or the symptoms are getting progressively worse. The type of surgery recommended will depend on the cause of your sciatica. Some surgical options include:

• discectomy – where the part of the herniated disc pressing on your nerve is removed (this is the most common type of surgery required)
• fusion surgery – it may be possible to fuse a vertebra that has slipped out of place by using a metal or plastic cage between the vertebra, supported with metal rods and screws
• laminectomy – a procedure often used to treat spinal stenosis, where a section of vertebrae called the lamina is removed.

Many people have a positive result from surgery but, as with all surgical procedures, spinal surgery carries some risks. Potential complications range from the relatively minor, such as an infection at the operation site, to the more serious, such as permanent damage to the spinal nerves. Before choosing spinal surgery, your surgeon will discuss the relative risks and benefits with you.

Source: NHS Choices.