December 5, 2021

What is a nerve block? What you need to know

What is a nerve block for anesthesia and surgery? Nerve blocks are powerful and safe anesthesia techniques to reduce pain and nausea, Dr. Kaveh explains.
What is  a nerve block for your surgery and anesthesia? Blocks can be very powerful for shoulder, arm, knee, and hip surgeries!

A nerve block is a powerful tool for your safety and comfort during surgery and recovery. I perform nerve blocks nearly everyday for my patients. Here is what you need to know about nerve blocks for your surgery and anesthesia.

What is a nerve block, Dr. Kaveh?

A nerve block is an injection of local anesthetic (like lidocaine) around a nerve. This blocks sensation of the skin, muscle, and bone. It makes you numb in the area you're having surgery. It's similar to what you have at the dentist's office. This helps reduce pain after surgery. In fact, many patients will feel no pain at all after their surgery, depending on their surgery and type of nerve block.

Depending on the surgery, many patients feel little, if any, pain after a nerve block.

Why do you get a nerve block?

A nerve block can address several major fears around surgery:

Pain is worst in the first 24 hours after surgery. Nerve blocks can significantly reduce the pain during this intense time after surgery. By reducing the pain, you also need less pain medication. Taking fewer pain medications reduces your risks for nausea, vomiting, constipation, and addiction.

Nerve blocks can be much safer than opioid pain medications after surgery and anesthesia. Nerve blocks have many advantages!

Reducing opioid use after surgery is very important. It only takes 5 days of opioid pain medication use to put you at risk for addiction after surgery. This is another reason why nerve blocks increase safety after surgery.

Other benefits of nerve blocks include:

  • Reduced anesthesia requirements.
    • Since you are numb in parts of your surgery site, you need less medication to keep you safely under anesthesia. Less medication means less chance of complications and side effects.
  • Reduced risks from opioids after surgery.
Nerve blocks can reduce pain, nausea, addiction, complications, and medication side effects. This can be incredibly empowering for patients.

Where do you inject the nerve block?

The nerve block injection site depends on where you're having surgery. It also depends on your health, and the surgeon and anesthesiologist's joint decision.

Some common nerve block injections are around the shoulder, abdomen, and knee. It all depends on where your surgery is.

How long will I stay numb?

You will stay numb until the medication is cleared by the body. This depends on where you were injected and the type of medication used.

Most patients are numb for 8-24 hours. Some nerve block medications can last up to 72 hours.

Muscle weakness with nerve blocks

If you are being blocked in your arm or leg, you may have difficulty controlling your limb. This is because the injection blocks nerves for both sensation and motor function. Patients describe the sensation as a "dead weight". Don't be concerned though, you will regain function of the limb once the medication wears off!

Are nerve blocks safe?

Your anesthesiologist and surgeon want you to be safe and comfortable during your surgery and recovery. Nerve blocks allow for both. My patients are sometimes concerned about long-term nerve damage from the nerve block injection. Fortunately, this is very rare, occurring in about 0.22% of patients.

This risk needs to be balanced with the risks of not having a nerve block. If you don't have a nerve block, you will likely have general anesthesia (see my upcoming article) and take opioid pain medications. Remember, opioid pain medications have their own risks after surgery.

The decision for a nerve block depends on many patient and surgical factors. I recommend you discuss the risks and benefits of a nerve block with your anesthesiologist before surgery. This will help give you the best outcome from your surgery and recovery. By learning about your anesthesia you're taking a powerful step in taking control of your surgery!


Ruhaiyem ME, Alshehri AA, Saade M, Shoabi TA, Zahoor H, Tawfeeq NA. Fear of going under general anesthesia: A cross-sectional study. Saudi J Anaesth. 2016;10(3):317-321.

Tick, Heather, et al. "Evidence-based nonpharmacologic strategies for comprehensive pain care: the Consortium Pain Task Force white paper." Explore 14.3 (2018): 177-211.

Greer, Susan M., et al. "Surgical patients' fear of addiction to pain medication: the effect of an educational program for clinicians." The Clinical journal of pain 17.2 (2001): 157-164.

Watts, S. A., and D. J. Sharma. "Long-term neurological complications associated with surgery and peripheral nerve blockade: outcomes after 1065 consecutive blocks." Anaesthesia and intensive care 35.1 (2007): 24-31.

Fredrickson, M. J., and D. H. Kilfoyle. "Neurological complication analysis of 1000 ultrasound guided peripheral nerve blocks for elective orthopaedic surgery: a prospective study." Anaesthesia 64.8 (2009): 836-844.

Abdallah et al. Will the Real Benefits of Single-Shot Interscalene Block Please Stand Up? A Systematic Review and Meta-Analysis, Anesthesia & Analgesia: May 2015 - Volume 120 - Issue 5 - p 1114-1129

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