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Leaflet: Nerve Root Blocks/Lumbar Sympathetic Block – Information for Patients

Your doctor has requested that you have a nerve root block either to help diagnose the cause of your pain or try to relieve it. We hope that the following information will answer some of the questions you may have about this procedure.

What is a nerve root?

Nerve roots exit the spinal cord and divide into nerves that travel to your arms and legs. These nerve roots can become inflamed due to pressure from nearby bone spurs or intervertebral discs.

Inflammation of nerve roots may cause pain in the back, neck/arms and/or the legs. A nerve root block provides important information for your doctor and may also provide you with some relief from pain.

Why do I need to have a nerve root block done?

The procedure is designed to prove which nerve is causing your pain by placing temporary numbing medicine over the nerve root of concern. If your pain improves after the injection then that nerve is the most likely cause of your pain. If your pain remains unchanged, then that nerve is probably not the cause of your pain.

What is injected around the nerve root?

The injection is a combination of local anaesthetic (a numbing agent) and steroid (an anti-inflammatory agent). The local anaesthetic works immediately and the steroid begins to work within 2-3 days.

Who has made the decision?

The doctor in charge of your case and the radiologist feel this is an appropriate procedure for you. However, you will have the opportunity for your opinion to be taken into account; if you do not want the procedure carried out then you can decide against it.

How do I prepare for a nerve root block?

There is no preparation for this procedure; you can continue to eat and drink as normal.

If you are diabetic please inform the doctor before the examination as there is a possibility that your sugar levels will vary after the injection. It is important that you continue to monitor your levels carefully for several days and consult your GP if necessary.

What will happen during the procedure?

You will be shown to a cubicle where you will be asked to undress in private and put on a gown. If you need assistance we can provide it.

  • You will then be shown into the X-ray room for the examination and introduced to the staff performing the procedure. You will be cared for by a small team including a radiologist/pain physician, radiographer and an X-ray department nurse.
  • Before the examination begins the radiologist/pain physician will explain what they are going to do and then ask you to sign a consent form.
  • You will then be asked to lie on your front or back on the X-ray couch. The skin will be cleaned and the doctor will inject a small amount of local anaesthetic under the skin. This stings for a few seconds and the area then goes numb.
  • The radiologist/pain physician will then direct a very small needle just next to the nerve root using the X-ray machine to guide the needle. Sometimes the needle can touch the nerve itself in which case you may feel a sharp pain going down your leg. This will only last for a second or two.
  • A special dye called contrast medium is then injected around the nerve root. This shows up on the X-ray machine to confirm the needle is in the correct position. When the radiologist is satisfied with the needle position, the pain killing medicine will be injected along the nerve root.

How long will it take?

You will be awake throughout the procedure, which lasts about 15 – 30 minutes.

Will it hurt?

You may feel a little pressure or discomfort, which may travel down the arm/leg, during the injection of the pain killing medicine. This will last for only a few seconds.

Afterwards your leg may feel numb or weak for up to 24 hours. You will be asked to wait for 30 to 60 minutes before going home and you should not drive for the rest of the day. You will need to arrange for someone to take you home.

Some people find that their pain feels worse for 2-3 days after the procedure. This is because the steroid can sometimes irritate the nerve. Do not worry if this happens, as it will settle down by itself.

If your leg becomes numb you may need to stay in hospital overnight.

Will the pain definitely improve and for how long?

About 8 out of 10 people experience some improvement of their symptoms as a result of the procedure. It can take anything from a few days to 6 weeks for your pain to reduce or resolve.

The pain relief may last from a couple of weeks up to a few months. We may ask you to keep a pain diary to record whether the procedure has been of any benefit. If it has helped your pain it may be possible for you to have the procedure repeated.

Are there any risks associated with a nerve root block?

Generally it is a very safe procedure. Potential complications are uncommon and include:

  • Bleeding or haematoma (a bruise under the skin) – this should settle down by itself.
  • If you are taking any form of blood thinning medicine (e.g. Warfarin, Aspirin or Clopidogrel known as Plavix) please arrange to see your GP for advice prior to attending for the injection
  • Infection – contact your GP if you experience any redness or tenderness at the injection site.
  • An allergic reaction to the contrast dye – please inform the doctor doing the nerve root block if you have any allergies.

The procedure uses X-rays to confirm that the needle is in the correct place. The amount of X-rays used is very small however female patients who are or who may be pregnant should inform the department before attending for their appointment.

Additional information for Pain Clinic patients having a lumbar sympathetic block:

What is Lumbar Sympathetic Block?

There are nerves running either side of the lumbar spine, that control blood supply to the muscles and skin of the legs. Injecting these nerves with local anaesthetic and/or a drug, may help your pain and improve your mobility.

What will happen during the procedure?

The procedure is done in the same way as a Nerve Root Block, except a dye is not injected.

What will happen after the procedure?

You will lie on your side and will have your blood pressure checked. You will be asked to stay in Day Case Unit for an hour.

You should not drive after this procedure. You will need an escort to take you home and stay with you overnight.

If your leg becomes numb, you may have to stay in hospital overnight. You can restart your normal activities the following day.

This leaflet can be provided in other formats and languages, please contact us for more information.

Date of creation: August 2017
Date of review: August 2019
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