Background Information

Back pain, and also pain arising in the buttocks or legs, may in certain cases be caused by pressure on nerve roots as a result of, for example, a slipped disc and/or from arthritic spurs of bone. This pressure can cause irritation and inflammation of the nerve roots and lead to pain.

A therapeutic epidural injection is an injection into the space around these nerve roots using local anaesthetic and slow-release locally-acting steroids. The steroids do not get absorbed into any large amount into your circulation and therefore do not cause side-effects elsewhere in your body.

The local anaesthetic provides temporary pain relief, and can cause numbness and weakness for a few hours. The locally-acting steroids produce long term reduction in the inflammation, but can cause some temporary soreness for a few days. In most cases, by the time the injection has worn off your body will have resolved the problem naturally.

The procedure

You will be admitted to hospital at least for a few hours, and the injection will be done in the theatre suite. You may be given a sedative, but you can drink normally and eat light meals at home on the day of your injection.

The injection is usually done with you lying on your side and is not nearly as unpleasant as some people think! Afterwards, you will have your blood pressure measured regularly, and depending on your case, you may have some manipulation while the back is numb.

You will not have normal bladder sensation for a few hours after, so you should empty your bladder before coming from the ward. You will need to rest in bed for a few hours afterwards, and must not drive yourself home if you are a day patient.

Possible complications

A slight drop in blood pressure is common and not serious. We measure the blood pressure routinely and from time to time need to put up a drip to correct the drop in blood pressure.

A very small number of people (1 in 500) may experience a severe headache afterwards, due to some leakage of the cerebro-spinal fluid, as a result of the injection, this is uncomfortable rather than serious, but can lead in some cases to another injection being required to plug the leakage.

There has been publicity about backache following epidurals for childbirth, this is a different situation peculiar to pregnancy and indeed the medications given are entirely different.

The results

We expect about one person in six to be completely cured of this episode of pain, and the remaining five out of six are usually improved. Sometimes the improvement is insufficient, and the epidural needs to be repeated. A few people are not helped and may require additional treatment or even surgery.