Having an epidural injection
What is an epidural injection?
"Epidural" describes the space surrounding the dura mater, the outer protective covering of the spinal cord.
An epidural injection consists of a steroid medicine and, usually, a local anaesthetic. The drugs are introduced into the epidural space using a special needle. The exact site of the injection depends on which level of your spine contains the nerves responsible for your pain. This is usually in the lumbar region of the back (under the level of your lowest rib).
If the first injection successfully relieves your symptoms, up to three injections to the same area of the back may be given over a six-month period.
An epidural injection is routinely performed as a day case, and so does not require an overnight stay in hospital.
You will be awake during the procedure, but you may be offered a sedative to help ensure that you are relaxed and comfortable.
The way steroids work for back pain is not fully understood, but there is good evidence that they help to relieve the type of pain that shoots down the leg. This is probably due to their anti-inflammatory properties. However, despite their effectiveness, using steroids for epidurals is not formally approved (licensed) by the Medicines Control Agency and you should be informed that this is the case before the medicine is given.
Preparing for the procedure
You may be asked about your medical history and any previous experience of hospital treatment. Your answers will help in planning for your care whilst you are in hospital.
Before you come into hospital, you will be asked to :
- Have a bath or shower at home on the day of your admission,
- Remove any make-up, nail varnish and bulky or sharp jewellery. Rings and earrings that youd prefer not to remove can usually be covered with sticky tape,
- Follow the fasting instructions in your admission confirmation letter. Typically, you must not eat or drink for about six hours before the procedure. However, you may be allowed occasional sips of water until two hours beforehand.
When you arrive at the hospital, your nurse will explain how you will be cared for during your treatment to the hospital and will help you prepare for the procedure. You will normally walk from your room, or the day care ward, to the theatre.
You will be given a consent form to sign. By doing this, you confirm that you understand what the procedure involves, including the benefits and risks, and give your permission for it to go ahead.
What to expect
In a private room or cubicle, you will be asked to remove your clothing and put on a hospital gown, which opens at the back. If you have them, you may also be asked to remove contact lenses, which will be kept safe for you during the procedure.
The procedure is usually performed in the operating theatre. If you are having a sedative injection, this will be given through a small plastic tube (a cannula) placed in a vein in the back of your hand. This will quickly make you feel relaxed and drowsy.
Once the sedative has taken effect, you will be asked to lie on your side. Your back will be cleaned with antiseptic solution. You may be given an injection of local anaesthetic to numb the skin, with a short, thin needle.
For the epidural injection, your specialist may take X-ray pictures to ensure the needle is correctly placed in the epidural space.
After the injection, the needle is removed and the site is covered with plasters or a dressing. You will be asked to lie on the side of your body that is most affected, to help spread the drugs.
After the procedure
You may be taken from the operating theatre to the recovery room, where your blood pressure
and pulse will be monitored, and the effect of the injection checked.
After this you will return to your room or the day care ward.
Back on the ward
You'll need to rest on a bed for around two hours. The nursing staff will be on hand to make sure you are comfortable. If you have had sedative, you may doze off during this time. Painkillers will be available to relieve any discomfort.
Before you leave hospital, a nurse will give you a contact telephone number for the hospital and a date for a follow-up appointment with the specialist. This will be two to six weeks later.
The effects of any sedative may last longer than you expect, so you should not drive, operate machinery or drink alcohol for 24 hours. This means that you will have to arrange for someone to take you home and stay with you for the first 24 hours.
After you return home
You may need to continue taking painkillers as advised for the first few days.
You should avoid strenuous exercise and expect to take one or two days off work. If you do manual work or are on your feet all day, you may need to take longer. Your specialist will be able to advise you further.
It may take several days until you feel the benefits of the injection, and up to a month for the full effect. This effect can last anything from a few weeks to several months. Some people find their back pain or sciatica recurs, for others it doesnt.
What are the risks?
An epidural injection for back pain is a generally safe procedure. For most people, the benefits in terms of pain relief are greater than any disadvantages. However, like all invasive medical procedures, there are some risks. These can be divided into the risk of side-effects and the risk of complications.
These are the unwanted, but usually mild and temporary, effects of a successful procedure. After an epidural injection you may feel a numbness and weakness in your back and legs. There may also be some soreness at the site of the injection for the first 24 hours or so and your symptoms of back pain may actually get temporarily worse, before they begin to get better.
Although the injection contains a steroid, this does not pass into the circulation in large quantities, so you are unlikely to experience the side-effects (such as nausea) sometimes associated with steroid tablets.
This is when problems occur during or after the procedure. Most people are not affected. The possible complication of any injection into the spine is that the treatment reaches unintended parts of the spinal column. This can result in a drop in your blood pressure or widespread numbness. This would become quickly apparent to your specialist, who can then provide appropriate care.
Other possible, but uncommon, complications include infection, developing a headache or damage to nerves. You may have a headache over the next day or two.
Very rarely, there may be bleeding into the epidural space. This may require an emergency operation to prevent paralysis.
The chance of complications depends on the exact type of procedure you are having and other factors such as your general health. You should ask your specialist and anaesthetist to explain how these risks apply to you.
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.