Check-up: Lumbar epidural steroid injections

With a recent diagnosis of sciatica, my GP referred me on to a specialist. She has recommendedan epidural steroid injection into my back. Can you explain what this is?

Sciatic pain is usually caused by irritation or compression of one or more spinal nerve roots in the lumbar spine. Although this can cause pain in the buttocks and down the leg, the problem is actually in the back.

For sciatic pain, an epidural steroid injection will be injected into the lumbar (lower back) area. A mixture of a dilute local anaesthetic and a long-acting steroid is injected into the epidural space that surrounds the spinal cord and nerve roots.

The aim of the treatment is to help reduce inflammation in that area.

What does the procedure involve?

Before the procedure, a small cannula will be placed in the back of your hand, through which a short-acting sedative will be given. This will make you feel relaxed. You may also be given oxygen during the procedure.

Lying, curled on your side, local anaesthetic will be used to numb the skin at the injection site and to numb the space between the lumbar vertebrae. An epidural needle is then passed through the skin into the epidural space with the aid of an X-ray image.

The anaesthetic and steroid mixture is injected slowly into the epidural space and you may feel a build-up of pressure in your back while this is done.

For a couple of hours after the injection, you will be positioned on your side, with the affected side down, to encourage the epidural medication solution to reach the affected area.

Most people can be discharged – with supervision – after a number of hours, or when all vital signs are stable.

What about side effects?

Soreness and bruising at the injection site, which typically settles after a few days, is common after epidural injection.

Less common side effects can include bleeding and haemorrhage into the epidural space or infection leading to an epidural abscess.

The spinal cord and nerves may be damaged by the needle, while puncture of the dural membrane can occur if the epidural needle is put in too far. Severe allergic reaction can develop due to the injection solution.

Epileptic seizures may occur and, in rare cases, numbness in the whole body can happen due to the local anaesthetic entering the spinal fluid.