Nerve root block


The aim of this injection is to try to ease the leg pain that you get. It is a form of treatment that has been used for a long time. It involves injecting local anaesthetic and steroid into the area that the nerve exits the spine. This is done under the guidance of X-Ray.

You will be awake during this procedure and local anaesthetic will be used to prevent discomfort. You will be on your side. We will clean the skin before putting the local anaesthetic in.

Needles will then be directed through the skin and muscles to where the nerves come out of the spine. This is all done under X-Ray control. Once we believe the placement is correct we will inject a dye that shows up on the X-Ray. When this is confirmed we will inject the local anaesthetic and steroid.

You will then be transferred to the recovery ward and soon after that back to the ward. This is usually done as a day case. The nursing staff will help you to get walking and once they are happy that you are walking safely they will allow you home. You will be reviewed in my clinic in about 6 weeks time. There is no restriction to your activity following the injection and you are encouraged to stay as active as possible. You will not need to take any time off work or refrain from driving.

The local anaesthetic will hopefully work straight away to reduce your leg pain. The steroid may take a while to work. It acts to reduce inflammation and irritability of the nerve. The local anaesthetic can have a similar effect as that when you visit the dentist. You may notice numbness and weakness in the leg, which wear off after a few hours. The procedure is successful in about 60% of cases.

In some people the pain relief may only last for the duration of the local anaesthetic – a few hours, or up to 6 – 12 months. This will hopefully allow you to start to become active and perform your physiotherapy exercises to produce a permanent improvement in your back. It is useful to know how much the pain was improved by and for how long. We will ask you this when you come back to see us in the clinic. This injection works not only as a treatment but also as a test to confirm that we have identified the correct level in the spine where the problem is. If the injection does not provide any benefit initially it is still possible for there will be a delayed effect. The steroid may start to work after a little while and it is still possible for the pain to improve even after two to three weeks. For 25% of people this is the only treatment that they will need. You should be aware that although steroids have been used in this manner for over 50 years they have not been through an approval process and are not licensed for this injection.

As with all procedures there are risks involved. The risk of a serious complication occurring is less than 1 in 100. This includes; infection, bleeding and clot formation, damage to the nerves, tear to the sac that contains the nerves and allergic reactions to the anaesthetic used. The most common complication is a leak of the fluid that usually surrounds the nerves. If this occurs people may experience a migraine type headache. This usually goes away if you lay flat for a few hours. People are still able to go home the same day, but they would have to stay in hospital for longer than they would otherwise. It is also possible for the injection to initially irritate the nerve and cause an increase in the pain. Once the local anaesthetic starts to work this will start to wear off.

You should contact me if you experience any of the following after your injection:

A loss of sensation or change in your ability to move your bowels or empty your bladder. 
Any significant leg pains and pins and needles.
Any redness, oozing or discharge from your wound.
Feeling unwell with a raised temperature


Once you are home, if you experience any complications or have any concerns please contact the ward. If they are unable to help you, please contact Mr Anjarwalla’s secretary and leave a message for him. We will try to answer your query as soon as possible. It is important to keep a record of any changes you notice, even if the pain goes away for a few hours this is important information. These injections are not only treatments but tests and all changes should be recorded and reported when I next see you.