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Nerve blocks for surgery on the arm or hand

Patient information A-Z


The purpose of this information leaflet is to explain what a nerve block is and how it helps to control pain. It also provides information on what to be aware of on the day of your surgery and on discharge home following a nerve block.

It will be of particular interest to people who might prefer not to have a general anaesthetic (GA), or have been advised that their surgery should be performed under a nerve block due to underlying health conditions.

As you may know an anaesthetic stops you from feeling pain and other sensations. You might have heard that it can be given in various ways and does not always make you unconscious. An anaesthetic is called “general “ when you are totally asleep but commonly for forearm, wrist and hand surgery regional anaesthesia is just given to the site being operated on. The anaesthetist will perform a nerve block by placing some numbing solution (local anaesthetic) around the nerves responsible for the sensations in your arm including for pain.

Patients who have had a nerve block remain generally awake throughout the operation, although some may also have sedation or general anaesthetic if appropriate.

The type of anaesthesia used is decided by you, the surgeon and the anaesthetist, but depends on the nature and duration of the surgery, your health, medical conditions and preferences.

What is a nerve block?

Your forearm, wrist and hand are supplied by a number of different nerves, which carry both sensory fibres (touch and pain sensation) and motor fibres (movement). By injecting local anaesthetic around these nerves, it is possible to ‘block’ these signals. In other words there will be a temporary numbness and weakness of the arm below the level of the block. Which nerves are blocked will be determined by the type of surgery you are having.

Diagram displaying nerves within the arm. Labelled: cords of brachial plexus; lateral, posterior, medial. Medial brachial cutaneous nerve. Medial antebrachial cutaneous nerve. Axillary nerve, musculocutaneous nerve, median nerve, radial nerve, ulnar nerve
Diagram of nerves within the arm

Brachial Plexus Block

The brachial plexus is the group of nerves that lies between your neck and your armpit. It contains all the nerves that supply movement and feeling to your arm: from your shoulder to your fingertips.

A brachial plexus block is an injection of local anaesthetic around your neck, collar bone or armpit to ‘block’ information (including pain signals) travelling along these nerves. After the injection, your arm becomes numb, heavy and immobile and you will feel no pain, although you may still feel movement and pushing or pulling as your arm is moved for you.

A brachial plexus block can provide pain relief for up to 24 hours after surgery, although some areas may have reduced or altered sensation for up to 48 hours. As the ‘block’ wears off you may experience pins and needles in your fingers – this is normal.


Advantages of choosing a ‘nerve block’ as part of your anaesthetic include better postoperative pain relief, faster recovery, less nausea, and a lower risk of blood clots. Having the operation whilst you are awake should allow you to be discharged quicker and avoid the side effects and risks that come with a GA (mainly sickness, drowsiness and sore throat). If you do have a GA, in addition to the nerve block then the pain relief that the ‘nerve block’ provides should mean you do not need to be given the strong pain relief drugs which can also make you sick and drowsy.

Your anaesthetist may suggest performing a brachial plexus block for a number of reasons:

To avoid the risks of a general anaesthetic

It may be possible to have your operation performed with a brachial plexus block alone. This may be particularly important if you have heart or breathing problems. You will be awake and pain free, although you may still be able to feel pressure and movement in the area.

For pain relief after your operation

The brachial plexus block can be given in addition to a general anaesthetic as it provides pain relief after the operation. This reduces the need for strong pain relief medicine which can make you feel sick and drowsy. It can also help the physiotherapists to start moving the arm, which helps recovery. You will have good pain relief for 12 to 18 hours after the operation and you should be able to manage on a small amount of pain killers as the numbness wears off. The nerve block is a more effective form of pain relief than painkillers and will help you be back at home quicker.

Side effects, complications and risks

In modern anaesthesia, serious problems are uncommon, but risk cannot be removed completely. Your anaesthetist will be able to give you more information about any of these risks and the precautions taken to avoid them. Brachial plexus blocks are not always completely effective. Sometimes the local anaesthetic does not spread to all the nerves. The operation you are having and your general body shape also affect the success rate. Your anaesthetist will be able to tell you how likely the block is to work fully. If the block does not work sufficiently for your operation, your anaesthetist will use another form of anaesthetic and / or pain relief.

Risk due to local anaesthetic drugs

  • Allergy to local anaesthetics can happen. It is very rare (less likely than allergic reactions caused by general anaesthetics)
  • An overdose of the local anaesthetic should not happen because your weight is taken into account when choosing how much local anaesthetic you need.
  • Serious problems including fits, heart or breathing problems can happen but they are very rare. Your anaesthetist is trained to deal with these emergencies.

Risk to nearby structures

If the injection is placed in the side of your neck (nerve block performed mainly for surgery on your shoulder), side effects include a hoarse voice, a droopy upper eyelid and feeling faint, especially on sitting up. Rarely, you may find breathing a bit more of an effort than normal. All these effects are temporary and should get better when the block wears off.

If the injection is placed around the collarbone (nerve block performed mainly for surgery on your upper arm and elbow), there is a small risk of damage to the lung (1 in 1000 patients). This can usually be managed to keep you safe and serious permanent harm is very rare. Your anaesthetist can tell you more if this injection is performed for your block.

For any operation on your forearm, wrist or hand, an injection under your armpit is generally the common choice for a nerve block.

For all injection sites, there is a small risk of bleeding due to damage to a blood vessel. This can be treated by direct compression and / or extra fluids given into a vein.

Nerve damage

Nerve damage can occur because of direct injection into the nerve or because of bleeding or infection. The risk of permanent nerve damage is rare. It is the same for all injection sites. An exact measure of the risk is not available, but the best studies we have suggest that it happens between 1 in 15,000 and 1 in 30,000 patients having a brachial plexus block. All human activities carry an element of risk. For example, 1 in 15,000 of us will die on the UK roads every year.

Patients commonly notice areas of tingling and/or numbness in the arm, shoulder or hand. This occurs in around 1 in 20 patients and usually resolves itself within three weeks, or occasionally up to three months.

There is a risk of nerve damage after any operation regardless of the type of anaesthetic technique used. This can be due to the operation, the position you lie in or the use of a tourniquet (a tight band on the upper arm, which prevents bleeding during the operation).

Swelling around the operation site or a pre-existing medical condition, such as diabetes, may also contribute to nerve damage.

If you have any questions please ask your anaesthetist, your surgeon or your nurses on the ward.

How is the block done?

The local anaesthetic injection is performed in the theatre suite where the anaesthetic assistant will ask you further questions and confirm the side of your body and area of your arm that will be operated on. A small plastic tube (cannula) will be inserted into the back of your hand, this is used to give you fluid and medication during the operation. Routine monitoring of heart rate, blood pressure and blood oxygen levels will be started.

The injection for a brachial plexus block can be either in the side of your neck, in your armpit, or close to your collar bone. Other nerves can be blocked near the elbow, or in the forearm, wrist or hand. The skin around the injection site will be cleaned and a small injection of local anaesthetic will be used to numb your skin- it does sting a little as it goes into the tissues. To help locate the nerve, the anaesthetist will use an ultrasound machine and / or a small machine that makes your arm twitch to locate the nerves, this twitching is not painful.

Most people find that the injection is no more painful than having a cannula inserted into a vein. When the needle is inserted, your anaesthetist will ask if you feel any tingling, or “twinges”, or an electric shock sensation. It can take more than one attempt to get the anaesthetic needle in the correct place to ensure that the area is completely numbed.

The anaesthetist will ensure you are comfortable and pain free throughout the procedure.

Your arm will start to feel warm and tingly before finally feeling heavy and numb. The injection typically takes between 20 and 40 minutes to work.

The anaesthetist will check the sensations you can feel in different parts of your arm and shoulder. Your operation will not start until the anaesthetist is happy that the block is working well. If the block does not work fully, you will be offered more local anaesthetic, additional pain relief or a general anaesthetic. You may be offered sedation before the injection to help you relax and feel less anxious. If you are having a general anaesthetic as well, this may be given before or after the injection. Occasionally we do not have the personnel available to carry out a nerve ‘block’ in which case we may only be able to offer a general anaesthetic.

During your operation

A screen will be positioned in a way that you cannot see the surgery being done. You may be able to listen to your own music on your own device with headphones during the surgery (please ask if this is possible).

An operating theatre is a busy place, there will typically be between five and eight people in theatre, each with their own role in helping to look after you. A member of your anaesthetic team will be with you throughout the surgery and sometimes other members of the team may also speak with you and help with your care.

If you are having sedation, you will be relaxed and drowsy. You may be given oxygen through a light plastic facemask. You may have memories of being in the operating theatre, although these may be patchy.

If you have a general anaesthetic you will not remember anything about the operation.

After your operation

Following the operation, you may return from the operating theatre with a sling or temporary splint. This sling or splint is often used to help keep you comfortable after the operation. While you are in the recovery area or ward, the staff will make sure your arm is protected from injury. You can expect to feel tingling as sensation returns but this soon passes. At this point it is important to let staff know if you are feeling any pain. It will take several hours for the feeling to return to your arm. This can be from 1 to 36 hours, depending on the type of anaesthetic injection that is used for your nerve block.

Your anaesthetist may be able to give you an idea of how long it should take. As the block wears off you may begin to feel more discomfort, although by this time a lot of the inflammation and swelling from the surgery should have subsided.

Usually your pain will continue to be well controlled with simple painkillers, although some patients require stronger painkillers. The requirements for these types of painkiller will vary from person to person.

Aftercare at home

If you are returning home on the same day as your operation, after leaving the hospital it is extremely important that you take the painkillers you have been given at the prescribed times you, from the moment of discharge. This is to avoid pain developing when the nerve block begins to wear off.

Your arm might still be numb when you return home from hospital as a result you will not be fully aware where your arm is and so it can be easily injured.

You should keep your arm in the sling you are given for support and protection. Take special care around heat sources, such as fires or radiators. You will not feel heat while your arm is numb and you may burn yourself. Avoid using your arm for difficult or heavy tasks

You will need to seek help from the emergency medical services if:

  • you notice unexplained breathlessness
  • you experience severe pain that is not controlled by your tablets

If the block has not fully worn off two days after the operation you should contact your anaesthetist by calling the number given on your discharge paperwork.


  1. Neal JM et al Brachial Plexus Anaesthesia: Essentials of our current understanding. Regional Anaesthesia and Pain Medicine 2002; 27(4): 402-8
  2. Borgeat A, Ekatodramis G, Kalberer F, Benz C. Acute and non-acute complications associated with inter-scalene brachial plexus block and shoulder surgery; a prospective study. Anesthesiology2001; 95: 875-880
  3. Saha S, Turner J. Nerve damage associated with peripheral nerve blockade. Royal College of Anaesthetists, patient information leaflets. Section 12. Royal College of Anaesthetists (opens in a new tab).
  4. Road Casualties Great Britain 2002: Dept of Transport (2003)

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