A nerve block is one way of giving pain relief, and this may be offered to you by your anaesthetist on the day of surgery. A nerve block is an injection of local anaesthetic placed near to a nerve or group of nerves to numb an area of your body. It will usually be performed along with a general or spinal anaesthetic.
Regional Anaesthesia UK have produced a very good patient information video about nerve blocks:
How is it performed?
It is often done before the general or spinal anaesthetic, and sedation is often given so you feel more relaxed. A small amount of local anaesthetic will be injected to numb the skin and the nerves to be blocked are found by using either an ultrasound machine or small machine called a nerve stimulator, which makes your muscles twitch. Sometimes it may be performed after your general anaesthetic whilst you are ‘œasleep’.
Depending on the operation you are having, the nerve block will be done at the side of the neck, around the collar bone, or near the armpit (for the arm); or in your groin, front of the thigh, behind your knee or at your ankle (for the leg). You will then be given either a general anaesthetic, or spinal anaesthetic with or without sedation, whichever is most appropriate, or occasionally you will be given just sedation during the operation.
What are the benefits?
- It will potentially avoid the need for or reduce the amount of strong painkillers required. This will avoid the side effects of strong painkillers such as drowsiness, nausea, vomiting, and confusion. This should make you feel much better and more clear headed after surgery
- Reduced stress on the body from improved pain relief
- You should be able to eat and drink after surgery sooner
- You will be ready to go home sooner as your pain will be better controlled
What are the risks?
Your anaesthetist will be experienced in performing nerve blocks, and the vast majority of patients will have no problems. However, all medical procedures carry some risks. Any questions can be raised with your anaesthetist on the day of your operation.
Risk explained
People vary in how they interpret words and numbers. This scale is provided to help:
Very common: 1 in 10
Equivalent to someone in your family
Common: 1 in 100
Equivalent to someone on a street
Uncommon: 1 in 1,000
Equivalent to someone in a village
Rare: 1 in 10,000
Equivalent to someone in a small town
Very rare: 1 in 100,000
Equivalent to someone in a large town
Incomplete or ineffective nerve block
This is fairly common (around 1 in 20 depending on the block or type of surgery). Your anaesthetist is trained to recognise this and will give you other forms of pain relief during the operation. When you are awake after surgery, further pain relief can be given if needed.
Bruising or bleeding
Mild bruising around the site of the nerve block is common and will resolve. Bleeding from larger blood vessels is uncommon, and can be dealt with at the time the anaesthetist is doing the nerve block.
Infection
Precautions against infection are taken and this is an uncommon complication.
Nerve damage
A nerve block usually wears off within 24 hours. It is fairly common (around 1 in 20) to have a slightly prolonged area of numbness and/or tingling lasting beyond 48 hours. Almost all of these symptoms will resolve over the following days, weeks or months but rarely this can be permanent.
It is difficult to accurately measure the risk of long term nerve damage due to it happening so infrequently. Studies have estimated this risk to be between 1 in 5,000 and 1 in 10,000 patients. Therefore the risk of nerve damage is rare.
There is a risk of nerve damage after any operation, even if you do not have a nerve block. This can be caused by the operation itself, the position you are lying in under anaesthetic, or the tourniquet on your arm or leg used during surgery. Swelling after surgery and medical conditions such as diabetes can also contribute to nerve damage after surgery.
After the operation
The effects of the nerve block usually last from a few hours up to 24 hours. Whilst the nerve block is working your arm or leg will feel numb, and it will also be heavy and weak. Keep your arm or leg in the sling or splint you are given until the block wears off to protect it. Be careful not to injure it, and be particularly careful around sources of heat. The effect will wear off gradually and feel tingly before the sensation and power return to normal.
You will be given oral painkillers on discharge from hospital. We recommend starting these whilst your arm is still numb, especially before going to bed, so they will be working when the nerve block wears off. Take the painkillers regularly for the next 48 hours and then judge for yourself whether you need to continue taking them.
If the block has not fully worn off by 72 hours, please phone the Day Surgery Unit on Tel: 0131 242 3291 / 3273 or via hospital switchboard on 0131 356 1000, who should put you in touch with an anaesthetist for further advice and assessment if required.
Further information
You will be able to discuss all this further with your anaesthetist on the day of your surgery.
The Royal College of Anaesthetists have produced an excellent patient information leaflet about nerve blocks for surgery on the shoulder, arm or hand
Interpretation and translation
Your GP will inform us of any interpreting requirements you have before you come to hospital and we will provide an appropriate interpreter. If you are having this procedure as an existing in patient, staff will arrange interpreting support for you in advance of this procedure.
PLEASE NOTE
This website includes content taken from the Royal College of Anaesthetists’ (RCoA) leaflets ‘Fitter, Better, Sooner (2018)’, ‘You and your anaesthetic (2020)’, ‘Anaesthesia explained (2015)’, and ‘Common events and risks in anaesthesia(2019)’. However, The RCoA has not reviewed the website as a whole. Some of the RCoA infographics used on the website have been adapted for web viewing.
