Dorsal root ganglion blocks to treat pain

Dorsal root ganglion blocks are used mainly for sciatic leg or arm pain, when other treatments have not helped. They are most commonly used in the lower back (lumbar region). It might help your pain by reducing some of the pain signals. The pain relief might only last a short time, but some people get significant and lasting pain relief from these injections.

The dorsal root ganglion is a swelling on a nerve that joins the spinal cord. It contains nerves that carry sensations from different parts of your body. A dorsal root ganglion block is an injection around the ganglion.

The procedure is sometimes called a transforaminal epidural. This is because the nerves enter through a hole in your back called the intervertebral foramen, and the injection might spread into the epidural space. It can also be called a nerve root injection.

The injections contain local anaesthetic, often with a small amount of steroids. The injections are usually given alongside other treatments, such as physiotherapy.

Other treatment options

The decision about treatment is shared between you and your doctor. Your doctor can give you information about the chances of this being a successful treatment for you, and how it fits into your care pathway.

If you are undecided about treatment, more advice and information can be provided. Please speak to your doctor about this.

Side effects

As with any procedure, you can have side effects. These are usually minor but there are risks with this procedure.

Common side effects

  • Mild tenderness or bruising at the injection sites, that usually settles over the first few days.
  • Numbness or weakness in your legs if you've had lower back (lumbar) injections, due to the local anaesthetic spreading. This is temporary and will get better within minutes or hours.
  • Numbness or weakness in your arms if you've had upper back (cervical) injections, due to the local anaesthetic spreading. This is temporary and will get better within minutes or hours.

Rare side effects

  • Infection that might need antibiotic treatment. This is rare. Seek medical help if there is warmth, redness or tenderness at the injection site, or you feel hot and unwell.
  • Your blood pressure might temporarily fall, and sometimes people feel faint.

Very rare side effects

  • Ongoing weakness of the legs, or incontinence (not being able to control when you pee or poo), that require urgent investigation and treatment. Serious nerve injury is extremely rare (less than 1 in 10,000 cases) but there are important nerves in the treatment area. Nerve injury happens when there is serious bleeding or abscess near the spinal cord. 
  • Severe headaches. On rare occasions the needle might be inserted too far, and reach the spinal fluid (CSF). This is called a dural puncture and can lead to headaches that need treatment. If you have a severe headache after your injection, take some paracetamol, drink plenty of water and lie flat. If the headache continues for more than 24 hours, contact your GP or the pain clinic.
  • Collapsed lung (pneumothorax), or damage to the lung (injections in thoracic area only). This is very rare. If you get chest pain or breathlessness, you should get immediate medical help.
  • In rare circumstances, steroids can damage your sight. You should report any new visual disturbance (such as blurred or distorted vision) to your doctor.
  • Very rarely, cervical injections have caused severe harm and even death. These complications are so rare it is difficult to say how often they happen. Please speak to you doctor of you are concerned.

Taking an unlicensed medicine

Steroids are often used to manage chronic pain, but are only licensed for some routes of delivery, such as tablets. Some ways of delivering the steroids are not on the license. This means that the manufacturer has not specified it can be used in this way. However, there is evidence that it works to treat this particular condition. This is called ‘off-label’ use, and lots of medicines are used this way to treat pain.

Read our information about unlicensed medicines. You can also call our pharmacy medicines helpline, phone 020 7188 8748, Monday to Friday, 9am to 5pm email [email protected]

We want 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. This states that you understand what the treatment involves and that you agree to have it.

Read more about our consent process.

Before treatment

If your health has changed, it is important to let the doctor know if you have:

  • an infection in your body or on the skin of your back (your doctor will postpone the treatment until the infection is cleared)
  • any allergies


Continue to take your medicines as usual on the treatment day, unless you are taking medicines that thin your blood, such as warfarin, rivaroxaban, heparin, or clopidogrel.

Please contact us at least 2 weeks before your injections to help us manage your medicines, if you:

  • are taking medicines that thin your blood, such as warfarin, heparin or clopidogrel (you might need extra preparation)
  • have diabetes. Steroids might cause your blood sugar to change, needing monitoring and adjustment of your diabetic medicines

You must also tell the doctor if there is any chance that you could be pregnant.

If you are planning to fly or travel abroad in the 2 weeks after the injections, please tell your doctor as it might be best to change the date of your procedure.

Always bring a list of all your current medicines.

During treatment

Not all doctors give these injections in exactly the same way, but this is generally what will happen:

  • Observations, such as blood pressure and pulse rate might be taken.
  • A small needle (cannula) might be put in the back of your hand.
  • You will be carefully positioned, and the skin around the injection sites will be cleaned with an antiseptic solution or spray. This can feel very cold.
  • An X-ray machine (or other form of image guidance) will be used to make sure we inject you accurately.
  • You will feel a stinging sensation as local anaesthetic is injected to numb the skin and surrounding tissues. Your doctor will tell you before they do this.
  • The doctor will direct the injection to the correct area. They will usually inject contrast (dye that is visible under X-ray) to make sure the needle is correctly positioned. When the injections are given, you might feel pressure, tightness or a pushing sensation in your back or leg. If there is any discomfort, let the doctor know.

After treatment

You will be taken to a recovery ward where nursing staff will monitor you. You will be asked to lay flat for about 30 minutes or longer. You will be told when to get dressed, and be given help to make sure that you can stand safely after the procedure. You will be given more advice when you are ready to go home.

Leaving hospital

You can usually leave hospital within a few hours of having the injection, and sometimes sooner. This will depend on how long your doctor or nurse wants you to stay for in recovery.

Please make sure that you have arranged for someone to collect you after the procedure. If this is not done, your procedure might be cancelled. It is unsafe for you to drive home immediately after the procedure. If you do, your motor insurance will not be valid.

You should arrange for someone to stay with you for 24 hours after your treatment. If this is not possible, you should at least have access to a phone.

For the first 24 hours, you should not:

  • drive
  • operate machinery
  • sign legal documents
  • provide childcare unsupervised
  • drink alcohol

If you are unsure, please discuss these issues with your doctor.

Before you go home you will be given information about who to contact if the pain unit is closed.

You might have some soreness or aching at the injection site for a few days.

Please keep injection sites dry for 24 hours after the procedure.

Do not worry if your pain feels worse for a few days, as this sometimes happens. Take your regular painkillers and medicines, and this should settle down. Try to keep moving about the house, but avoid anything too strenuous.

As your pain decreases, you should try to gradually increase your exercise. Simple activities like a daily walk, using an exercise bike or swimming on your back, will help to improve your muscle tone and strengthen your muscles. It is best to increase your activities slowly. Try not to do too much on a good day as it can cause you to have more pain the next day.

If you are unsure, or finding exercises increasingly difficult, please contact your GP or the pain team and discuss a referral to physiotherapy.

Call 999 if:

  • you get chest pain or breathlessness

Contact your GP or the pain clinic if:

  • you have a severe headache that continues for more than 24 hours (take some paracetamol, drink plenty of water and lie flat)
  • there is warmth, redness or tenderness at the injection site, or you feel hot and unwell (these could be signs of an infection)

Returning to work

This will be different for everyone, and might depend on the type of work you do. You should discuss this with your doctor.

Follow-up appointments

You will receive details of a follow-up appointment. It will be a phone call or at the hospital, with a nurse specialist or consultant. If you haven’t heard from us within 10 weeks after the procedure, please contact us, phone: 020 7188 4714, Monday to Friday, 9am to 5pm.

Leaflet number: 5374/VER1
Date published: January 2024
Review date: January 2027

Contact us

If you have any questions about your treatment at our hospitals, please contact the clinical nurse, voicemail 020 7188 4714 or email [email protected]. We prioritise by clinical urgency, but try to respond to all messages within 3 working days. Our office hours are Monday to Friday, 9am to 5pm.

If you have any questions about appointments or admissions, please
phone 020 7188 8877 or email [email protected]

Adapted from information by the Faculty of Pain Medicine of the Royal College of Anaesthetists.

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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