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Nerve Blocks

What is a nerve block?

Regional anaesthesia (nerve block) is where a nerve or group of nerves in a specific area of the body can be made numb by a local anaesthetic injection. Using local anaesthetic can sometimes allow you to stay awake for the procedure. Local anaesthesia provides long-lasting pain relief, during and after surgery. It can last from 2 to 18 hours, depending on the injection site and which medicines are used. Your anaesthetist will explain the particular nerve block that is selected for your surgery. In some operations, the nerve block will be combined with sedation and/or a general anaesthetic. Your doctor will discuss with you the type or types of anaesthetic which are suitable for you and your operation.

What are some advantages of a nerve block?

  • reducing the need for other anaesthetic medicines or possibly avoiding a general anaesthetic altogether
  • pain relief after your surgery which will assist you with moving about earlier
  • less need for strong pain-relieving medicines, such as morphine, and their side effects, including nausea, confusion, drowsiness, and constipation.
  • The above benefits may lead to a reduced stay in hospital for you.

    While nerve blocks definitely improve pain control, they are not superior or inferior in efficacy to medication in your drip. For this reason, if you feel uncomfortable with a nerve block, your pain can be managed in other ways.

What happens during the procedure?

A drip will be placed in your arm or hand. You will be monitored throughout the procedure. You might receive some sedation prior to the nerve block. Your anaesthetist will ask you to keep still while the injections are given. You may notice a warm tingling feeling as the anaesthetic begins to take effect. Usually, the block is done under ultrasound guidance. Your operation will only go ahead when you and your anaesthetist are sure that the area is numb. It usually takes about 20 minutes for the block to take full effect. You will remain alert and aware of your surroundings, unless you are having sedation. A screen shields the operating site, so you will not see the operation unless you want to. If you are having sedation, you will be sleepy and relaxed. However, you may be aware of events around you. Your anaesthetist is always near you and you can speak to him or her whenever you want to.

What are the risks of nerve blocks?

Common risks and complications:

  • Pain, bruising and/or bleeding at the injection site
  • bleeding is more common if you have
    been taking blood thinning drugs, such as warfarin, aspirin, clopidogrel.
  • Prolonged numbness or tingling.

Uncommon risks and complications

  • Failure of block: this may require a further injection of anaesthetic or a different method of anaesthesia to be used
  • Temporary nerve damage recovering in a few days to months, damage may cause weakness, tingling and/or numbness of the body part that the nerve goes to
  • Overdose of local anaesthetic solution (local anaesthetic toxicity)
  • Allergic reaction to the medication, requiring further treatment
  • Small areas of the lung can collapse, increasing the risk of chest infection. This may need antibiotics and physiotherapy
  • Damage to surrounding structures such as blood vessels, nerves and muscles.

Rare to very rare risks and complications

  • Permanent nerve damage
  • Equipment failure (e.g. breakage of needles or catheters possibly requiring surgery to remove them)
  • Serious allergic reaction or shock to the medication, requiring further treatment
  • Infection at the site of injection, may require antibiotics and further treatment
  • Heart attack or stroke could occur due to the strain on the heart
  • Seizures may occur, requiring further medication and treatment
  • Death as a result of this anaesthetic is rare.

Additionally, there are certain complications exclusive to certain blocks. Please ask your anaesthetist about these.

The above infographic describes what is meant by common, uncommon and rare risks

What to expect after the procedure:

  • The area that has been blocked may remain numb or weak for up to 24-4 hours.
  • Take care not to injure or bump the area that has been numbed with the local anaesthetic as you will not be able to feel pain do not place hot or very cold things on the affected part as this could cause burns
  • If you have a ‘weak’ leg, do not walk without a person to assist you
  • Ask your doctor/health professional whether you can drive any type of car, bike or other vehicle and operate machinery including cooking implements
  • If the numbness/weakness has not gone away after 24-48 hours, contact your doctor/ clinician
  • There can be a significant increase in pain when the block wears off. Take prescribed pain medications as directed as soon as you notice an increase in pain.

This information pamphlet has been adapted from the information pamphlets used by the Royal College of Anaesthesiologists in the United Kingdom ( https://www.rcoa.ac.uk/patients ) and the Government of Queensland, Australia.