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Nerve Blocks

Nerve blocks are safe and commonly used to temporarily numb many areas of the body, particularly the legs, arms and chest wall. It involves injection of local anesthesia near nerves. Nerve blocks are also called regional anesthesia. It can be used as a sole anesthetic agent or as part of an anesthetic for pain relief. Once the injection has been done, it is common for the area to feel weak and heavy until the medication wears off. This can take up to 24 hours. 


Anesthesiologists are specialist doctors who have undergone many years of training to perform these procedures. Your treating anesthesiologist will discuss what they believe is the best way to care for you during your procedure. 


They’ll discuss with you what their plan for the anesthetic involves and answer any questions you have. 


The nerve block can be administered before going into the operating room, or in the operating room or in the recovery area depending on your situation. 

An ultrasound will often be used by your anesthesiologist to locate the nerves involved. They will first clean the area with cold cleaning solution and then place local anesthetic under your skin first. They will then carefully move a needle near your nerves to inject the medication for the nerve block. It is common to feel a pressure sensation while they do this, but a nerve block should not be a painful procedure. The procedure normally takes about 5 minutes to complete. 

You will have an opportunity to ask questions if you have any prior to the procedure. While we have asked you to review this information, your anesthesiologist will review their personalized plan for your care with you on the day of surgery and discuss any risks that are relevant to you. 

Benefits of nerve blocks:

1. Can help you go home sooner, as there are fewer side effects like nausea and drowsiness  

2. Reduce side effects of pain medications 

3. Sometimes you can avoid a general anesthetic if you have a nerve block

4. Better control of pain after surgery


This is a link to a video from Regional Anaesthesia UK of a nerve block being performed if you wish to view it:


Administering a nerve block using ultrasound guidance

Image credit: Moffitt Cancer Center

Common complications of nerve blocks 

Temporary nerve symptoms (tingling, a patch of numbness or weakness) after nerve block occur to about 2 in 100 patients who have a nerve block. 

Rare complications of nerve block

Permanent nerve injury after nerve block is so rare that it is difficult to know the exact rate. It occurs to about 1-1.5 in 10 000 (0.01 - 0.015%) patients who have a nerve block.

Toxicity or allergic reaction from local anesthetic is very rare.

Infection at the injection site from a nerve block is very rare.

Depending on the type of nerve block performed, there is a risk of damage to the structures near the nerve. This is why ultrasound is commonly used to carefully find where the needle is at all times during a nerve block. 

People vary in how they interpret numbers. We have provided this infographic to assist with your interpretation. 

Very Common


These side effects happen to more than 1 in 10 people. This is equivalent to one person in a family.


These side effects happen to between 1 in 10 and 1 in 100 people. 

This is equivalent to one person in a street


Between 1 in 100 and 1 in 1000

This is equivalent to one person in a small village



Between 1 in 1000 and 1 In 10000

This is equivalent to one person in a small town

Very Rare

1 in 10 000 to 1 in 100 000 people.

This is equivalent to one person in a large town or city

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