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A nerve block of your foot or ankle means temporarily numbing the nerves which go to your foot or ankle with local anaesthetic. The foot or ankle can be made numb enough to be operated on painfree. Depending on the nature and duration of your operation, you may, however, need additional sedation or another form of anaesthetic. Your anaesthetist will discuss this with you.
The numbness will last several hours, then it will start to wear off and normal feeling and power will eventually return.
In the anaesthetic room or operating room the anaesthetist will insert a cannula into a vein in your hand and attach you to monitoring for your heart and lungs. This is routine for every anaesthetic.
Two nerves supply the foot and ankle with feeling and power: one at the front of the leg and one at the back. There is also a circle of nerves around the ankle. You may need one or several of these nerves to be numbed. The nerve blocks can be done whilst you are awake, sedated or anaesthetised. The nerves can be easily found with the use of ultrasound, or occasionally with a nerve stimulator. The nerve stimulator will cause twitching of your knee or ankle, and if necessary you can have light sedation for this.
The nerves are blocked by visualising them on the ultrasound screen and injecting local anaesthetic around them. This takes around 10 to 20 minutes to work. The ankle and foot will then feel warm, tingly, weak and numb. Whilst you are awake, you may still feel dull pressure or movement, but you should not feel any pain.
After surgery, the foot or ankle will continue to be numb for about 10 hours, but this can last between 4 and 24 hours. The numbness will wear off gradually, and normal strength and feeling will return.
Numbing the nerves will make your operation site pain free for the duration of the numbness, and depending on your operation you may be able to avoid a general anaesthetic.
This is good for you because:
If you have a general anaesthetic as well, the pain relief will still be beneficial.
As a guide:
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Foot and ankle operations are frequently planned as a day case procedure, which means you go home on the same day. Whilst your foot or ankle is still numb, it will be protected by a special boot or shoe, and you will be given specific instructions for walking and weightbearing. If you are given crutches, you will have opportunity to practice using them.
You can start to eat and drink after the operation when you feel like it and it is safe.
It is difficult to predict exactly how long the numbness will last. As it starts to wear off, there may be a tingling sensation. When the numbness does wear off, it is likely the foot or ankle will be sore. You will be given some painkillers to take home with you. Please follow the instructions carefully for how to take the painkillers. Take them regularly for two days, starting when you get home, or at the latest before you go to bed. After two days you can decide whether you still need them.
Occasionally there may be ongoing patchy numbness or weakness, which may still resolve completely after several days.
Can I eat and drink before a nerve block?
No. You will still need to follow the fasting guidelines you were given by the hospital. This is in case you need to have a general anaesthetic as well.
Must I stay fully conscious?
Not necessarily. Your anaesthetist can discuss with you the options of being awake, being sedated and being anaesthetised. If you have sedation or a general anaesthetic, you will need somebody to pick you up and stay with you for 24 hours.
Will I see or hear anything?
If you are sedated or awake, there will be a screen between you and the operation, and you will not be able to watch. Whilst you are awake, you may be able to keep your hearing aids in and your spectacles on.
You will find more information about nerve blocks on these websites:
www.rcoa.ac.uk ‘For Patients and Relatives’
Please look here for a video on surgery under nerve block on the Regional Anaesthesia United Kingdom website.
This leaflet is intended for patients receiving care in Brighton & Hove or Haywards Heath.
The information in this leaflet is for guidance purposes only and is in no way intended to replace professional clinical advice by a qualified practitioner.
Publication Date: September 2021
Review Date: June 2024