Dr Thomas E Smith MBBS(Hons) MD FRCA FFPMRCA
The aim of this information sheet is to help answer some of the questions you may have about having an epidural injection to treat your pain. Thoracic, Lumbar, and Caudal Epidural Injections are performed for back and leg pain due to spinal nerve irritation. Selective Nerve Root Blocks are a very targeted kind of epidural, also known as a Transforaminal Epidural. This sheet explains how they are performed, the benefits, risks and alternatives of the procedure as well as what you can expect when you come to hospital.
What is an epidural injection?
The space around the spinal cord and large nerves within the spine is called the epidural space. An epidural injection directs medication into this space with the aim of calming irritated nerves and relieving pain. Two types of medicine are usually used – a local anaesthetic and a corticosteroid.
Corticosteroids medicines are not licensed to be given as an epidural injection, and their use is termed ‘unlicensed’. They have however been used this way worldwide for many years, and it is considered to be standard practice.
What happens during an epidural injection?
The injection is performed in the theatre environment using x-rays to help with precision needle placement.
- You will be placed lying on your front.
- Antiseptic is used to clean the skin on your back/neck and a local anaesthetic injection is given to numb the skin, to minimise any pain when the epidural injection is given.
- With most epidurals, the needle passes through the numb skin, between the bones of your spine and into the epidural space under x-ray guidance.
- With a selective nerve root block, the needle is passed beside the spine to lie next to a nerve as the nerve leaves the spine through a nerve window (foramina).
- Contrast dye is injected and viewed by x-ray to confirm that the needle is in the correct place.
- A mixture of local anaesthetic and steroid is then injected through the needle and then the needle is removed.
What are the benefits – why should I have this procedure?
The aim of the procedure is to provide you with temporary or more permanent pain reduction. If successful, this may help you increase your physical activity and reduce your pain medication.
What are the risks?
No procedure is entirely risk free. This type of procedure carries a minimal risk of side effects or complications. These may include:
- A headache – occurs in around one in every 200 cases.
- Diabetics may experience a rise in blood sugar for a few days.
- A skin infection where the needle was inserted, causing redness, swelling or discharge of pus – estimated to be one in every 1000 cases.
- Bleeding and bruising at the injection site – this is usually mild.
- Temporary numbness/weakness as a result of the local anaesthetic – this usually resolves in a few hours. Rarely, it may require you to stay in hospital overnight.
- Allergy to injected drugs – estimated to be one in every 40,000 cases.
- Nerve injury such as numbness or weakness lasting days or weeks – estimated to be one in every 1000 cases.
- Permanent nerve injury is so rare it is hard to be exact but a figure of one case per 30,000 procedures is suggested.
- Paralysis is very rare indeed, but cases have been described – usually connected to other risk factors
Are there any other alternatives?
By the time you consider an epidural injection you should have already tried other more simple treatments. These could have included physiotherapy and pain medicines.
Giving your consent
Dr Smith wants to involve you in decisions about your care and treatment. If you decide to go ahead, you will be asked to sign a consent form that states that you agree to have the treatment and you understand what it involves. But you can still ask questions after this.
What happens on the day of the procedure?
Please remember to bring with you:
- dressing gown and slippers
- any medication you normally would take (unless already advised not to)
- something to read and your mobile phone.
A nurse will admit you. You will be given a gown to change into. You can put your own dressing gown on over this gown while you wait.
Please note the time stated on your letter may not be the time of your actual procedure. This is a time set to make sure that you are prepared and ready for your procedure. Therefore, you may have to wait for a while in the preoperative area. A friend or relative will be able to stay with you while you wait.
All women of child-bearing age will be asked to provide a urine sample, for us to test to rule out pregnancy. You must tell us if you could be pregnant. X-rays are safe for adults, but may harm your developing baby, so they aren’t usually done during pregnancy.
It is important that you take all your medication as usual, apart from blood thinning drugs (for example warfarin, rivaroxaban, clopidogrel), or specific diabetes medication (for example insulin or metformin). If you take blood thinning drugs or diabetes medication, then please inform us at least two weeks before your injection, to help us manage these.
Will I feel any pain?
The procedure may be performed either with you awake or sedated – Dr Smith will discuss this with you. Local anaesthetic will be used but some brief pain with the injections can be expected.
What happens after the procedure?
You will need to stay in the procedure facility for at least 30 mins after your procedure so your recovery can be monitored and we are sure that it is safe for you to go home.
Please arrange for a responsible adult to drive you home or accompany you in a taxi. We do not recommend public transport because it is not safe if you feel unwell.
You will be able to leave as soon as your nurse is satisfied that you are well enough and that there is a responsible adult to accompany you.
What do I need to do after I go home?
After the procedure and for the rest of the day, it is important for your safety that you follow the advice below.
Please rest at home for the remainder of the day.
For 24 hours after the procedure, do not:
- drive any vehicle, including a bicycle
- operate machinery
- cook, use sharp utensils or pour hot liquids
- drink alcohol
- make any important decisions or sign any contracts.
It is important to mention that some people feel pain relief immediately after the procedure. Some people feel no immediate change but pain relief develops over subsequent days. Some people feel worse for a short period before pain relief develops. If you experience some initial soreness you should take your usual painkillers and rest until it settles.
Will I have a follow-up appointment?
Yes. You will have either a clinic or a telephone appointment to assess the effectiveness of the procedure.