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 leg (lower 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 leg. 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 behind your knee, in your ankle or foot, or near your groin.

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.

There may be clinical reasons not to use a nerve block, such as having an allergy to the type of anaesthetic or materials used, or an infection at the site where the needle will be inserted.

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 then 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 two 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.

How can I prepare myself for the operation?

Keeping warm

It is important to keep warm around the time of the operation. The healthcare team will take steps to keep you warm when you are having the operation.

The hospital may be colder than your home, so bring extra clothing or a dressing gown.

Lifestyle changes

If you smoke, stopping smoking now may reduce your risk of developing complications and will improve your long-term health.

Try to maintain a healthy weight. You have a higher risk of developing complications if you are overweight.

Regular exercise should help to prepare you for the operation, help you to recover and improve your long-term health. Before you start exercising, ask the healthcare team or your GP for advice.

What complications can happen?

Some complications can be serious and can even cause death.

• the nerve block not working properly
• allergic reaction
• allergic reaction to the equipment, materials or medication
• bleeding
• nerve damage
• visual disturbance or loss of vision
• local anaesthetic toxicity

Summary

A peripheral lower 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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