CT guided foraminal, nerve and epidural steroid injections are given close to the nerves of the neck or lower back as they leave the spine, or into the epidural space within the spine.

The injection may help to confirm that compression or irritation of a particular nerve is responsible for your symptoms, and aims to provide relief from neck, back, leg or arm pain.


You will lie on the CT table on your front. Your skin will be cleaned with antiseptic where the needle will be given and a local anaesthetic will be injected. The radiologist inserts a fine needle into the location that your doctor has asked us to inject using an aseptic technique (strict infection control practices). The CT machine is used to guide the placement of the needle safely and accurately into the correct position, and a small amount of x-ray contrast or air may be injected to help confirm this.

A long-lasting anaesthetic (e.g. Ropivacaine) and a long-acting steroid (e.g. Celestone) are usually injected together.

Before your Scan

It is essential that your previous x-ray, CT or MRI films are available at the time of the injection. Please bring these with you if you have them.

If you are on any medication or have diabetes and are on insulin, take your usual medicines and diet.

Please inform us if you are on medication to thin your blood (eg. Warfarin, Aspirin or Clopidogrel), have an iodine allergy, or are pregnant or breastfeeding.

Before the procedure, you may be asked to change into an examination gown for your comfort, and to ensure clothing does not affect the images. You may also be asked to remove jewellery, eye-glasses and any metal objects that might interfere with the imaging.

Your doctor may request this procedure to be performed with sedation, in which case you will be required to fast (not eat or drink anything) before the procedure, and a short stay hospital admission will be necessary.

You will require someone to collect you and take you home after the injection.

Risks / Side Effects

Side effects may include:

  • Worsening of symptoms and weakness for 24-48 hours.
  • Increased blood sugar levels in diabetics.
  • Insomnia, flushing and palpitations.
  • Local bruising and soreness. Infection is an uncommon, but serious side effect.

Serious side effects causing permanent neurological damage can occur extremely rarely.

If x-ray contrast is given, there is a small risk of an allergic reaction, which may include flushing, hives and difficulty breathing. Severe reactions are rare, and a life-threatening reaction is extremely rare (1 in 170,000). Read more on IV contrast.

Other Information

Following the injection, you may feel numbness, tingling and weakness in the leg. This will wear off after several hours.

The local anaesthetic may give pain relief initially but will wear off after a few hours and the pain may return. It can take several days for the steroid to begin to work and may take up to 2 weeks for it to have maximum effect.

The effect of the steroid can last for a week, several months or years. Sometimes there is no pain relief from the injection.

Avoid strenuous activity for at least 48 hours after the injection.

If required, a simple analgesic such as paracetamol (Panadol) or anti-inflammatory should be sufficient. An ice pack may also provide some relief.

Infection is a potential and serious side effect. If you notice any fever or redness, swelling, or increased pain at the injection site after the first 2 days, notify your referring doctor or immediately call the clinic where the injection was performed.

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