The epidural space is between the dural sac (a membrane encasing the spinal cord, spinal fluid and nerve roots) and the vertebral wall.
An epidural steroid injection (ESI) is an injection that delivers long-acting steroids directly into the epidural space. The steroids help to reduce the pain by reducing inflammation around the nerves. A local anaesthetic also used to ‘flush out’ inflammatory agents that may be irritating a nerve.
Epidural steroid injections are typically used to treat pain radiating from the lower back into the legs or from the neck into the arms. The conditions most often considered for ESI are herniated discs, stenosis, nerve root compression and in some cases spondylolisthesis.
Before the Procedure
- An epidural injection is a day case procedure. You will come in the morning and you will probably be able to go home in the afternoon.
- Do not eat or drink for 6 hours before your injection
- You can take your regular heart and blood pressure medications on the morning of the injection with a sip of water. Check with your doctor regarding
- taking diabetes medications prior to the injection.
- Discontinue taking anti-inflammatories three days before the injection
- Discontinue taking aspirin products and other blood thinners seven days before the injection
- If on blood thinners call the doctor who prescribed the medication to get approval to stop taking them before the injection.
During the Procedure
- The patient lies flat on his/her abdomen on an x-ray table
- A local anaesthetic is administered to the injection site and some sedation is also given so patients don’t feel any pain during the procedure
- Using live x-ray for guidance, the consultant directs a needle toward the epidural space.
- The needle is inserted into the base of your spine just near your coccyx. There is a small triangular opening there which allows access to the spinal canal.
- A small needle is inserted and a radio-opaque dye is injected to confirm that the needle is in the correct space.
- The steroid solution is injected (you may feel some heaviness and/or numbness in your legs caused by the anaesthetic). This generally only lasts a few hours
- An epidural steroid injection usually takes between 15 and 20 minutes.
After the Procedure
- Following the injection the patient is usually monitored for 15/20 minutes before being discharged to go home
- It is important that the patient have someone to drive him/her home after the injection
- Patients are usually asked to rest on the day of the injections
- Normal activities including work may typically be resumed the following day. Please note your back may be sore for 24/48 hours.
- The effects of the epidural are variable in their onset and so some people might notice an immediate benefit where in others it may take up to 10 days to feel some pain relief.
- Whilst the epidural injection is relatively safe and quick to perform, it has the disadvantage of being unpredictable in its action and short lived in its effect.
- Some patients do not respond to the injection.
- For those who do respond, its effect may last from 4 – 6 months. There is no definitive research to dictate how often a patient should have ESI’s. In general it is considered reasonable to perform up to 4 ESI’s per year.
- The procedure is generally safe and we rarely see any problems.
- Occasionally patients report some bladder dysfunction but this usually improves in 24 hrs