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.
Operations on lower limbs are usually performed under a general anaesthetic or spinal anaesthetic. A nerve block is usually used in addition to give pain relief afterwards. Depending on the operation, the injection may be given behind your thigh or knee, in your ankle or foot, or near your groin.
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 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.
What complications can happen?
Some complications can be serious and can even cause death.
- Failure of the nerve block
- Allergic reaction
- Nerve damage
- Visual disturbance or loss of vision
- Local anaesthetic toxicity