What is a peripheral nerve block?

A peripheral nerve block is a type of regional anaesthetic that involves injecting local anaesthetics and other painkillers near the major nerves to your arm (upper limb).

How does a nerve block work?

A nerve block works by temporarily numbing your nerves to give pain relief. Local anaesthetics and other painkillers are injected, using a fine needle, near the nerves to your arm. You may need more than one injection.

A nerve block can be used instead of a general anaesthetic for the operation and is also an effective form of pain relief afterwards. Depending on the operation, the injection may be given in the side of your neck, or near your collarbone or armpit, or in your elbow, forearm or wrist.

What will happen if I decide not to have a nerve block?

If you decide not to have a nerve block, your anaesthetist may be able to suggest other methods of pain relief. During and after the operation you may need more painkillers that are more likely to make you feel sick or drowsy.

What does the procedure involve?

Your anaesthetist will usually use an ultrasound scanner or nerve stimulator to help guide them where to inject the anaesthetic.

Your anaesthetist will insert the needle and when they are certain that it is in the right position they will inject anaesthetic through it. They will usually remove the needle.

Sometimes your anaesthetist may insert a small tube (catheter) through the needle before they remove it, leaving the tube in place so they can inject more anaesthetic.

What effect does a nerve block have?

A nerve block has 2 main effects.

• Pain relief — The nerve block numbs the sensory nerves responsible for pain and touch.
• Weakness — The nerves supplying muscles may also be affected.

What complications can happen?

Your anaesthetist will try to reduce the risk of complications.

Any numbers which relate to risk are from studies of people who have had a nerve block. Your anaesthetist may be able to tell you if the risk of a complication is higher or lower for you. Some risks are higher if you are older, obese, you are a smoker or have other health problems. These health problems include diabetes, heart disease or lung disease.

Some complications can be serious and may even cause death.

• Change in your breathing. Your breathing will improve as the anaesthetic wears off.
• The nerve block not working properly.
• Allergic reaction to local anaesthetics.
• Allergic reaction to the equipment, materials or medication.
• Bleeding.
• Nerve damage. This is usually temporary, with symptoms of numbness or weakness lasting up to 12 weeks. Sometimes the damage can last longer than 6 months or be permanent.
• Visual disturbance or loss of vision.
• Local anaesthetic toxicity. You may feel light-headed and have a seizure.
• Pneumothorax, where air escapes into the space around your lung. If a lot of air escapes, this can cause a large pneumothorax. The air will need to be sucked out using a needle or let out by inserting a tube in your chest.
• Droopy eyelid on the side of the nerve block.
• Developing a hoarse voice.

Summary

A peripheral upper limb nerve block can be used for most people, usually giving a safe and effective form of pain relief both during and after the operation.

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