Epidural anaesthesia, often referred to as "an epidural", is an injection in the back that numbs the nerves and stops you feeling pain.
Areas that can be numbed by an epidural include the:
How an epidural works
Anaesthetic medicine is injected into an area of the spine known as the epidural space.
The anaesthetic works by numbing pain nerves as they enter the spinal cord.
The extent of the numbness will depend on the type of drug used, and the amount injected. Once the medication has worn off, feeling in the affected areas will return.
When is an epidural used?
An epidural can be used to provide pain relief in situations including:
during an operation, instead of a general anaesthetic after surgery that has been carried out under general anaesthetic
This topic focuses mainly on having an epidural during labour and childbirth.
Epidurals have been routinely used for many years and are widely accepted as an effective method of pain relief after surgery, and during labour and childbirth.
However, as with many medical procedures, there are some associated risks that, although small, you should be aware of before deciding whether to have an epidural. Two possible risks include:
puncture of the dura – the toughest, outer layer surrounding the spinal cord and brain; the risk of the dura being punctured is about one in 100
nerve damage – which occurs only very rarely
Pain relief in labour
Techniques to help you cope, including relaxation, gas and air, a birthing pool or epidural
When an epidural is used
An epidural is a type of local anaesthetic. It can be used to completely block pain while you are awake.
This has the advantage of allowing you to avoid the potential complications and common side effects of general anaesthetic, such as feeling sick and dizzy.
Epidural anaesthesia can be used to numb sensation and provide pain relief in situations including:
during a caesarean section – where a baby is delivered through a cut made in the abdomen
after surgery that has been carried out under general anaesthetic
during other types of surgery – such as knee surgery, hip replacement surgery, rib or chest fractures, and amputation of the lower limbs
Epidurals are most commonly associated with pain relief during labour and childbirth. This topic focuses mainly on this use of epidural anaesthesia.
Mobile epidurals, also known as walking epidurals, are low-dose epidurals that may be used during labour. A smaller amount of local anaesthetic is used in combination with other painkilling medicines.
As your nerve sensations are not completely blocked, a mobile epidural gives pain relief without as much of the numbness or heavy-legged feeling that’s experienced during a full epidural.
Another advantage of a walking epidural is that you will be able to feel the contractions and the need to push during the final stages of labour.
As you still have some sensation in your legs, you can also move around if you need to, although it’s not always recommended.
Why epidurals might not be used
In rare cases, an epidural isn’t recommended. For example, it may not be suitable if you:
are allergic to local anaesthetics
are taking medicines to thin your blood, such as warfarin
have a blood-clotting abnormality that increases your risk of bleeding
have previously had back surgery, or you have other problems with your back
have a spinal deformity or severe arthritis in your spine
have a neurological condition that affects your nervous system, such as spina bifida
Your anaesthetist can provide you with more information and discuss the potential risks in these situations.
How an epidural is performed
If you choose to have an epidural, the procedure will be carried out by an anaesthetist. An anaesthetist is a doctor trained in providing patients with pain relief during medical procedures.
Having an epidural
Epidurals are given in the lower back area. Most are given while the patient is sitting down and leaning forwards. Alternatively, an epidural can be carried out while you’re lying on your side with your knees drawn up and your chin tucked in.
Lying or sitting in these positions opens up the spaces between the bones of your spine (vertebrae) and allows the needle to be passed into the epidural space more easily. This is an area through which the nerves from your spine to your body pass.
A sterilising solution is rubbed into your back and sterile drapes are placed over your back, leaving the injection site exposed.
An injection of local anaesthetic may be given to help reduce any discomfort. A hollow needle is then inserted and a thin, plastic tube (epidural catheter) is passed through the middle of the needle, into the epidural space. The epidural anaesthetic can be injected through the tube.
If you are having an epidural during childbirth, you will need a drip in your hand so fluid and medicines can be given to help prevent low blood pressure, which is a common side effect of epidurals. The drip may restrict you from moving around freely.
You may experience a brief stinging sensation as local anaesthetic is injected into the skin. You may also feel slight discomfort when the epidural needle is positioned, and the catheter is inserted.
If you feel pain or an electric shock-like feeling, tell your anaesthetist, because the catheter may be pressing against the root of a nerve and may need to be repositioned.
Effects of an epidural
Shortly after having an epidural you will experience a warm, numbing sensation in your lower back and legs. Your legs may feel heavy and more difficult to move. It usually takes about 20-30 minutes for the epidural to take full effect.
The nerves in your bladder are also likely to be affected by the anaesthetic. This means you won't know when your bladder is full, and whether you need to go to the toilet. To prevent damage, a catheter will be used to drain urine from your bladder. Your bladder sensation will return to normal when the epidural is stopped.
How long does an epidural last?
While the epidural catheter remains in your back, it can be used to relieve pain. This can be for several hours (during labour) or for a few days, (after major abdominal surgery).
The catheter can be connected to an automatic pump to allow the medication to be topped up. Pumps that allow you to control the dose can also be used.
When the epidural drugs are stopped, the numbness usually lasts for a few hours before its effects begin to wear off, and feeling starts to return.
After having an epidural
Following epidural anaesthesia, you will probably be advised to rest in a lying or a sitting position until the feeling in your legs returns. This can take a couple of hours and you may feel a slight tingling sensation in your skins as the anaesthetic wears off.
Tell the doctor or nurse if you feel any pain. They can give you medicines to help control it.
After having an epidural, you will be able to breastfeed your baby.
Side effects and complications of an epidural
Sometimes, an epidural may not work. This can happen if:
it’s difficult to find the epidural space
the local anaesthetic doesn’t spread evenly around the epidural space
the catheter falls out
If your epidural doesn’t work, your anaesthetist may offer alternative pain relief or perform the procedure again.
Epidural anaesthesia is usually safe; however, as with most medical procedures, side effects and complications can sometimes occur.
Low blood pressure
Low blood pressure (hypotension) is the most common side effect associated with having an epidural. This is because the local anaesthetic used affects the nerves that go to your blood vessels, leading to a fall in blood pressure. This may cause lightheadedness or nausea.
Your blood pressure will be closely monitored while you’re having an epidural. If necessary, medication can be passed through a drip to treat low blood pressure.
Loss of bladder control
After having an epidural, you will not be able to feel when your bladder is full because the epidural affects the surrounding nerves.
A catheter inserted into your bladder allows urine to drain away. Your bladder control will return to normal as soon as the epidural wears off.
Sometimes, the painkillers combined with the anaesthetic during an epidural can cause itchiness. This can usually be easily treated.
You may feel sick (or be sick) after having an epidural. If your blood pressure is normal, anti-sickness medicines will usually help.
A study carried out in 2010 found no increased risk associated with the use of epidural anaesthesia and long-term backache.
Your epidural care team will try to make sure you’re comfortable during and after the procedure, but being in the same position for a long time may make existing backache worse.
If you experience severe backache following an epidural, you should let your care team know as soon as possible, so they can investigate the problem.
Occasionally, a severe headache can develop after an epidural – known as a post-dural puncture headache.
This happens when the lining of your spinal cord (dura) is accidentally punctured.
The headache usually clears up with time, but a procedure known as a "blood patch" may be used to seal up the hole. It involves taking a small sample of your blood and injecting it into the epidural space. When the blood clots (thickens), the hole will be sealed and your headache will stop.
Headaches caused by a punctured dura are rare following an epidural. There’s a 1 in 100 to 1 in 500 chance of it happening.
It’s possible for an infection to develop at the site of the injection in the weeks following an epidural. This can lead to an abscess forming. Very rarely, abscesses can form in the epidural space. This may lead to nerve damage, including the complete loss of movement of the lower half of the body (paraplegia).
An epidural haematoma is a very rare complication of an epidural. A haematoma is a collection of blood that develops as a result of a break in a blood vessel wall.
If the veins inside the epidural space are punctured, blood can build up and a haematoma can develop, causing pressure on your spinal cord.
Very rarely, this may lead to nerve damage, such as paraplegia.
Other possible, although rare, complications of an epidural include:
However, serious complications following an epidural are rare. The best estimate of the overall risk of permanent harm from an epidural in labour is between 1 in 80,000 and 1 in 320,000.
Before deciding to have an epidural, you should discuss the procedure with your anaesthetist. They can provide further information and advice on the risks of developing complications such as those described above.