What is a nerve block?
A nerve block is a technique of using local anaesthetic fluid to surround nerves and put them 'to sleep' temporarily. The local anaesthetic will cause numbness and tingling in the affected area and reduce pain signals from the operative site. It may also cause temporary weakness of the muscles in that area.
How is it done?
These can be done either awake or asleep but usually after you are asleep. A high fidelity ultrasound machine is used to locate the relevant nerves. The skin is cleaned and a probe is inserted adjacent to the nerves and fluid injected under low pressure around the nerves under direct ultrasound vision.
What are the benefits?
Nerve blocks can significantly reduce pain signals from the operative site and therefore reduce the risk of experiencing severe pain during your recovery. This can have benefits both in the short term with additional comfort but also longer term by potentially reducing the risk of persistent pain in the operative site.
What are the risks?
This is considered a safe technique. However it is important to avoid inserting needles directly into nerves and injecting under pressure as this can damage the nerves. We use the highest quality ultrasound machines and specially adapted needles that reflect ultrasound to reduce this risk significantly.
THERE IS ALSO A RISK THAT THE PAIN MAY BECOME SEVERE WHEN THE NERVE BLOCK WEARS OFF
We will do several things to avoid this. These will include giving you local anaesthetic by direct injection into the surgical site (in addition to the nerve block) when you are asleep, adding long acting pain medication during the surgery and tablets such as PALEXIA SR after surgery before the nerve block wears off. There will be 'top-up' quick acting pain tablets available every 2 hours, such as PALEXIA IR or hydromorphone. Please ask your nurse for a pain tablet sooner rather than later if you start to feel noticeable pain while the nerve block is wearing off.
What are the other effects of the nerve block?
Depending on where the nerve block is done and what type of surgery you are having you may also experience some additional effects from the nerve block.
Operations on the shoulder
The shoulder & upper arm will feel numb and heavy but your hand should still feel relatively normal in strength but pins & needles are common. Because the nerves to the shoulder, elbow & hand are close together the hand may also become completely numb until the nerve block wears off. Occasional you may also notice a hoarse voice, droopy eyelid or mild shortness of breath. These are all temporary effects until the local anaesthetic wears off.
Operations on the elbow or wrist
Nerve blocks for this type of surgery will usually result in quite a numb hand with expected loss of all feeling and movement in the hand for the duration of the block, usually 8-16 hours.
Operations on the knee
Nerve blocks for knee operations may or may not affect the muscles of the thigh depending on the type of surgery & nerve block. Generally we try to avoid muscle weakness but THERE MAY BE A RISK OF FALLS due to leg weakness and general instability after surgery. Please ensure that you receive assistance when trying to get out of bed the first time after any knee operations
IF YOU HAVE ANY PERSISTING NUMBNESS, WEAKNESS OR UNUSUAL SENSATIONS IN THE AFFECTED AREAS BEYOND 1-2 DAYS AFTER THE BLOCK HAS WORN OFF PLEASE CONSULT YOUR SURGEON OR ANAESTHETIST FOR FURTHER ASSESSMENT