The drugs will also block signals to the muscles. Your lower body will be numb and your legs will feel weak and clumsy. When we stop injecting the drugs normal sensation and muscle power return. This will be within an hour or two of the operation finishing. Sometimes the epidural catheter is left for a day or two after the operation, if you are likely to be in pain for that long.
The aim is to allow you to have a pain-free operation. The epidural may also be used to provide pain-relief after your operation.
By having an epidural alone you can avoid the risks of a general anaesthetic, where you are unconscious for the operation. Compared with a general anaesthetic, an epidural causes less nausea. It also allows you to keep a clear head so that you feel normal again more quickly. This allows you to eat, drink and be up and about as soon as possible.
You can have the epidural simply for preference if your operation is suitable, as some patients prefer to be conscious during their surgery.
Smokers benefit from an epidural, as they do not need to breathe the irritant gases used during a general anaesthetic. This irritation may cause coughing after the operation, especially in smokers.
The most useful benefit is the several days of pain-relief that the epidural can give after an operation. When your wound has settled and there is less pain, we remove the epidural. Simple painkilling tablets or injections are then used instead.
Are there any alternatives?
There are several alternatives to an epidural:
- Spinal injection - It may be suitable to have a single injection, similar to an epidural, but without putting in a catheter. This single injection is called a spinal. It does not last as long as an epidural. It cannot be left in for pain relief after the operation.
- General anaesthetic - You can have a general anaesthetic, where you are unconscious for the operation. Strong painkillers, such as morphine, can be given to keep you comfortable when you wake up. There may be a medical reason why a general anaesthetic is not suitable and you should discuss this with your anaesthetist.
- Regional anaesthetic - Another method is to make individual nerves go numb temporarily. This could be your whole leg or arm. One such anaesthetic is called a Bier’s block. Because it makes a small region of the body numb, it is called a regional anaesthetic.
- Local anaesthetic - Sometimes, if the surgery is minor, local anaesthetic injections can be used to numb the operation area only.
- Hypnosis - More recently, patients have used hypnosis to help them during an operation. Very few people can tolerate operations with hypnosis alone, but it may assist with the relief of anxiety, when used with nerve blocking methods
Whether any of these alternatives are suitable depends on the part of the body to be operated on. The length of the operation is also important. All of these methods can be used with sedation into a vein to help relieve anxiety.
If you are to have one of these procedures there is another information leaflet that will tell you more about it.
Who should have it done?
There are general reasons for having an epidural, instead of a general anaesthetic. These are:
- If you have had a previous problem with a general anaesthetic.
- If you have moderate to severe lung disease.
- If you have any other disease that may be made worse by a general anaesthetic, such as bad asthma or kidney disease.
- If you are having an operation where an epidural can be used to control pain after the operation.
There are some specific reasons for having an epidural. The most common reason is when a baby is delivered by Caesarean section. The mother can bond with the child immediately after the operation, because they are both awake. Also, the drugs given to the mother do not affect the baby, as in a general anaesthetic. An epidural is commonly used during the labour and can be left for the Caesarean section.
Another reason for using an epidural is when there is a history of allergy to general anaesthetic gases. There is a rare but serious condition, which runs in families, called malignant hyperpyrexia. Anaesthetic gases and other drugs used during a general anaesthetic can cause an increase in body temperature in patients who suffer from this condition. An epidural would avoid this.
Who should not have it done?
If you are unwilling to have an epidural and another type of anaesthetic would be safe, then we would not do an epidural. There are also specific medical situations when an epidural should not be done and these are:
If you take medication that prevents your blood from clotting, such as Warfarin. This could lead to bleeding in the spine, which is a serious problem and must be avoided. The anaesthetist may still be able to do an epidural but will have to do a test first to check the clotting of your blood.
If you have an illness that prevents your blood from clotting, such as haemophilia. This could also lead to bleeding in the spine. Again, a blood clotting test may be done first.
If you have infection of the skin where the needle is put in. This could lead to infection in the deeper tissues and possibly septicaemia. This could also cause infection around the spine.
If you have an allergy to any of the drugs used during the epidural. You should tell your anaesthetist of any allergies you are aware of.
If you have unusual or difficult spinal anatomy, such as severe arthritis or previous spinal surgery. This could make it difficult to put the epidural needle in the correct place.
Author: Dr Sean White FRCA. Consultant in pain and anaesthesia
© Dumas Ltd 2006