A caudal epidural is an injection of a mixture of local anaesthetic and hydrocortisone (steroid) around the areas of inflammation in the spinal canal. This is used when nerves in the lower back are inflamed due to irritation from either spinal stenosis (a degenerative narrowing of the spinal canal) or a disc prolapse. In addition to the mechanical irritation, there can also be a chemical irritation to the nerves from chemicals that can be released from a damaged disc. The injection is not a cure, but aims to alleviate your symptoms by reducing the inflammation caused by both the mechanical and chemical irritation of the nerves.

It is unusual to perform a caudal epidural on its own. Usually a caudal epidural injection will be performed in conjunction with a foraminal injection.

How do we do it?

A caudal epidural is carried out as a day case procedure in an operating theatre. To minimize discomfort the injection is performed under sedation, which is administered by an anaesthetist. The injection is carried out through the sacral hiatus, which is a small opening in the base of the spine just above the coccyx. The position of the needle is confirmed by injecting some dye and taking an x-ray.

What Are the Risks?

Infection

There is a risk of infection at the injection site, but this is rare due to the use of sterile techniques.

Dural Punture

There is a small risk of a headache if the needle punctures the lining that surrounds the nerves. This is incredibly rare following a caudal epidural injection.

Haematoma

There is a very small risk of a haematoma forming around the nerves causing further nerve compression. This is normally only a problem in patients who are on medication to thin their blood (aspirin / warfarin / clopidogrel). You must inform us if you are on any of these drugs, as they will need to be stopped for a few days before your injection.

If you are on any medication that has the potential to thin your blood such as aspirin, clopidogrel, warfarin or any other blood thinning medication then we do need to know about this prior to the date of your injection.

Temporary Numbness & Bladder Disturbance

following the injection you may experience some numbness between your legs and extending into the tops of your thighs. This is due to the local anaesthetic effect on the nerves, and wears off after a few hours. Occasionally, the local anaesthetic can also effect the nerves to your bladder, disturbing your bladder function for a few hours. We will make sure that you have passed urine before you go home.

Injection Site Discomfort

Following the injection you may have some localized discomfort at the injection site, for which you can take some simple painkillers and it should settle over a few days.

Side Effects from the Injected Steroid

There are very few side effects when steroids are administered this way. Occasionally patients may notice some facial flushing, nausea, or mild abdominal cramps for a few days following the injection. There can also be a temporary disturbance to the menstrual cycle. Diabetics may find that the steroid alters their blood sugar control for a few days, so should monitor it closely.

Allergic Reaction

An allergic reaction to injected steroid and local anaesthetic is incredibly rare. However, you must inform us of any know allergies before hand.

What Can I Expect Following the Injection?

You will normally be able to leave hospital once you are mobile and have passed urine. This is normally 2-3 hours following your injection. As you will have had sedation you will be unable to drive for 24 hours following the injection, and will need to arrange for someone to collect you from hospital. We would advise that you have a restful day the day after your injection, but can return to normal activities the following day. There are no other restrictions following the injection.

Approximately 65% of patients have a good response following a caudal epidural. However, the benefits are not always long lasting. The hydrocortisone can take a couple of weeks to have its full effect, so you may not notice an immediate benefit. If further rehabilitation is recommended, it is important that you undertake this whilst you are pain free so that you gain maximal long-term benefit. It is important that you build up any unaccustomed activity gradually.

What Next?

You will be seen back in the clinic a few weeks after your injection. Your on-going treatment will be guided by your response to the injection.