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What is an Epidural injection?

Your doctor or surgeon has referred you for a lumbar epidural corticosteroid (steroid) injection as they believe that it may provide short term (up to 3 months) relief of your severe or prolonged (chronic) radicular back pain. Steroid medication decreases inflammation, and the injection is most suitable when the pain is caused by disc or facet joint problems related to ageing and arthritis. It is not recommended for back pain that is the result of other causes, such as cancer in the spine or infection.

The spine has many parts including the spinal cord, bony vertebrae and spongy discs. The epidural space is a long canal surrounded by bony vertebrae; it protects the spinal cord. The nerves which travel to various parts of the body leave the spinal cord via a nerve root. Under the guidance of a CT scanner, an injection of steroid medication and long-lasting local anaesthetic can be accurately made into the epidural space. The procedure is performed by a specialist doctor called a radiologist.

How long will the procedure take?

The procedure itself takes approximately 15 to 30 minutes. Our staff will monitor you for up to 3 hours after the procedure to ensure that your leg(s) and bladder function are normal, your blood pressure is normal, and you can sit up and walk normally without feeling dizzy. You may be in our practice for up to 4 hours.

Is there any special preparation required?

When booking your appointment, it is essential that you inform our staff if you have any allergies, take blood thinning medication, or are pregnant or breastfeeding.

Please list or bring all of your prescribed medications, those medications that you buy over the counter, including herbal remedies and supplements.

If you take blood thinning medication, you may need to stop taking these for a few days or reduce your dose. It is very important that you do not stop any blood thinning medications or change the dose without consulting with our radiology clinical staff and your own doctor. They will give you specific instructions about when to stop and restart the medication. These drugs are usually prescribed to prevent stroke or heart attack, so it is very important that you do not stop taking them without being instructed to do so by your doctor or our clinical staff, or both. Aspirin is usually not stopped.

A blood test may be required to check your blood clotting on the day before the procedure. You should continue with pain medication and all other medications as usual.

What do I need to do on the day of the procedure?

It is common to experience numbness or weakness in your legs immediately following the injection.
You, therefore, will need someone to drive you home after the procedure, and we advise you not to drive for the rest of the day.

The injection is performed with you lying on your stomach. If your stomach is ‘too full’, this can be uncomfortable. It helps to limit your food intake to a light meal in the 2 hours before your appointment.
For a short time (one to two hours) after the procedure, you may not feel your bladder filling as you usually do. It is recommended that you limit the amount of fluid your drink in the 2 hours before your appointment, and you should go to the toilet immediately before the procedure begins.

On the day of your appointment, please ensure you bring:

• Your referral form (if you have it)
• All previous relevant scans or x-rays
• Medicare and healthcare cards (e.g. DVA card or concession card)
• List of all medications

What happens during the procedure?

A CT scan assists the radiologist in identifying the injection site; this may be marked on your skin with a pen. An antiseptic solution is used to clean the skin, and a sterile drape applied to your back to reduce the risk of infection.

You will remain awake during the procedure. To prevent discomfort, the area where the epidural injection will be performed may be numbed using local anaesthetic. Local anaesthetic causes a pinprick and stinging sensation that is uncomfortable for a few seconds.

Guided by the CT images, the radiologist will place a thin needle into the epidural space, confirming the correct location using a contrast medium (x-ray dye) or air. After confirmation of the correct position of the needle, the corticosteroid and long-acting local anaesthetic are injected. You will need to stay as still as possible. A small number of patients report an increase in their back or leg pain when the injection starts. This pain is temporary and eases off when the anaesthetic spreads into the epidural space. Once the needle is removed, a waterproof dressing will be applied to the site.

Are there any after effects from the treatment?

• You may not have the usual control over your bladder in the first couple of hours after the procedure. This includes not noticing that your bladder is full, which may lead to leakage of urine (urinary incontinence); this is the reason for suggesting that you limit your intake of fluids and empty your bladder right before the procedure.
• Your leg(s) will feel numb for a while following the injection; this can be from 1 to 2 hours. This can be worrying; however, it is important to be aware that the feeling and movement recovers.
• The procedure can also cause a temporary drop in blood pressure, making you feel dizzy if you sit or stand up.

Our staff will monitor you closely, including the sensation in your legs, your bladder sensation and your blood pressure.

What happens after the procedure?

Our staff will provide you with clear written instructions on ways to look after yourself following the injection. This includes information such as; avoiding strenuous activity for a few days, arranging a follow-up appointment with your referring doctor and how to look after the injection site.

What are the benefits?

The injection can assist in the relief of back pain and avoidance of or delay in surgery. The pain relief is often not permanent, the injections can be repeated if the pain returns. The generally accepted practice is to limit this to no more than three to four injections per year.

The injection may aid in your pain management by allowing you to undertake appropriate physiotherapy and help in breaking the pain cycle. The pain relief may be effective for several weeks to months.

Are there any risks?

In referring you for this injection, your doctor believes that the benefits of this procedure for you are greater than the risks. There are some risks and complications associated with lumbar epidural steroid injection. The use of the CT scanner to guide the procedure minimises these risks.

• CT uses ionising radiation to produce the images. The radiation doses associated with guiding an epidural injection are minimal and the associated risks are negligible.
• If the layer of tissue surrounding the spinal cord is inadvertently punctured, the procedure will be stopped. This can occur when the spinal canal is very narrow due to disc disease or arthritis and the epidural space is extremely narrow or non-existent, making it hard to position the needle. You may experience a severe headache for a few days. Sometimes an additional procedure may be necessary to seal the puncture.
• Urinary retention means you cannot empty your bladder; it is an uncommon complication. If this occurs, a thin tube (catheter) is passed into your bladder through the urethra (the passage leading from your bladder to the outside). The catheter is only temporary and will be taken out. You will need to stay in hospital until your bladder function returns to normal. This side-effect generally only occurs when large volumes of anaesthetic are used to relieve pain. It is more common in men who already have some problems with bladder emptying due to an enlarged prostate.

Less common risks and complications may include infection or damage to surrounding structures such as blood vessels, organs and muscles. Some people may have an allergy to injected drugs, or the procedure may not be possible due to medical or technical reasons.

Before the injection the radiologist will discuss the procedure with you in detail, including any risks specific to you. You will be provided with the opportunity to ask questions. It may be necessary to do a formal consultation to ensure that the procedure is the most appropriate for you.

When do I get the results?

The radiologist will send a report outlining the procedure to your referring doctor/ surgeon and your regular GP. It is important that you make a follow-up appointment with your referring doctor / surgeon if the injection has not helped to ease your pain.

I still have questions; who can I ask?

Medical information can be complex and you may receive information that you do not fully understand. It is important for you to consider the risks and outcomes of the procedure, as well as your personal needs before making a decision to undergo the procedure.

If you have read this online information and are still unsure if this is the correct procedure for you; before you make a booking, you should discuss your questions or concerns with your referring doctor in the first instance. Your regular GP and/or your family may also be a useful resource. Your referring doctor can answer questions about the risks and benefits of not having the procedure and other alternative options for treatment.

If you have questions before your appointment about what is involved on the day, our staff would be happy to assist. Please contact the imaging centre where you have made your appointment.