What is a Nerve Block?: Your Guide to Regional Anesthesia

If you are scheduled for surgery, you might be surprised when your surgeon or anesthesiologist recommends a nerve block. Here you’ll find out exactly what it is, how it’s done, what the benefits are, and what complications could arise.

Nerve blocks are placed by anesthesiologists  to help minimize or eliminate the pain of surgery. Most often, nerve blocks are performed for orthopedic surgeries and can drastically reduce the amount of discomfort you may have after surgery. This can help speed up the recovery and rehabilitation process.

In most cases, the nerve block is provided in addition to general anesthesia. That way, you can be asleep for your surgery and then wake up with less pain.

For example, for major shoulder surgery, your orthopedic surgeon may feel that a nerve block would be beneficial for you. In the usual scenario, the nerve block is placed prior to general anesthesia. So you would have a shoulder that is essentially numb (and pain free) whenever you wake up from your shoulder surgery.

What is a nerve block?

Simply stated, a nerve block is the placement of local anesthetic (eg. lidocaine) and perhaps some additive medicines onto, or near, a nerve or bundle of nerves. This serves to “numb” the area that nerve supplies, decrease/stop the ability to move, and provide pain relief for surgery in that location.

How it’s Done:

Once you have spoken with everyone involved, including your surgeon and anesthesiologist, and all your questions have been answered and your consent for the “block” obtained,  your nerve block can be placed.

Your anesthesiologist gives you “relaxing medicine” through your IV, places monitors to ensure your safety (eg., blood pressure, EKG, pulse oximetry) and then gets ready to perform the nerve block. There are several techniques to properly locate the nerve(s). The most common in use today include visualization with ultrasound and/or the use of nerve stimulation. Once you are comfortable from the IV medicine, the procedure will begin.

A few moments are spent identifying the correct area of your body where the nerves of interest are located. For the nerves that provide sensation to your shoulder, for example, the nerves are often “blocked” by placing medicine near your neck. For knee surgery, some of the nerves to be blocked are located near your groin.

Once the correct area for the nerve block is identified by the anesthesiologist, numbing medicine is placed into the area. This numbing medicine, or local anesthesia, can last greater than 24 hours in some cases. Alternatively, a nerve block catheter may be placed that will continuously infuse numbing medicine into the extremity for several days of pain relief.

Nerve blocks performed:

We typically perform nerve blocks for surgeries including orthopedic shoulder surgeries of all varieties, carpal tunnel surgery, hand surgery, hip replacements, knee replacements, knee ACL reconstructions, ankle surgeries, and foot surgeries. If you have a fractured extremity, your orthopedic surgeon might ask the anesthesiologist to place a nerve block to help decrease the pain in this extremity as well. Sometimes, nerve blocks can be used as the sole anesthetic for some surgeries, including carpal tunnel surgery and foot surgery. The principle is that if your arm or leg is numb, you don’t experience any pain!

The nerve blocks most commonly used are the interscalene block, supraclavicular block, infraclavicular block, axillary block, lumbar plexus block, femoral block, sciatic block, popliteal block, and ankle block. However, there are other blocks that can be performed depending on your type of surgery.

Benefits of Nerve Blocks:

As mentioned above, the overwhelming benefit is a decrease in post operative pain. This means you will likely need less of the IV pain medicine that has the potential to make you sleepy, nauseated, constipated, or itch. You may be able to participate earlier in physical therapy, and you may even be able to go home quicker (decreasing your chance of a hospital-acquired infection or medical error).

Also, with a nerve block in place, the anesthesiologist will not need to give you as much pain medicine while you are asleep under general anesthesia. This can lead to less post operative nausea and vomiting as well as a quicker recovery from general anesthesia.

Potential Complications of Nerve Blocks:

With any procedure that physicians do, there is always the possibility of complications. Fortunately, the incidence of major complications from nerve blocks is very low. The most common thing I tell patients is that the nerve block might not take away all of the pain after surgery. If this occurs, your nerve block can be supplemented with IV or oral pain medicine.

Also, the nerve block may not work at all. While this is an unlikely scenario, this potential still needs to be discussed. Your anesthesiologist may offer to place the nerve block again after surgery if this occurs.

A feared complication of nerve blocks is the potential for permanent numbness (or any other neurologic symptom) to occur in the extremity. This is very rare. In fact, if numbness in the extremity does continue longer than expected, in the large majority of cases, the numbness will eventually resolve and is not permanent.

Another potential complication is that the local anesthetic might be injected into a blood vessel. This can potentially lead to “local anesthetic toxicity.” This is a serious complication that may cause your heart to stop. And for this reason, anesthesiologists monitor you throughout the placement of the nerve block and immediately afterward to watch for signs of toxicity; ready to give rescue medicine if necessary.

We often use an ultrasound machine to watch where we inject the medicine, and we can see blood vessels with this technology.

Other potential side effects are bleeding and infection. The skin through which the block is placed is cleaned with a sterile solution and sterile gloves are used. Infection is rare. Also, unless a blood vessel is inadvertently pierced, the likelihood of serious bleeding from a nerve block is also rare.

And once again, this is why anesthesiologist monitor you throughout the placement of a nerve block.

Why You Wouldn’t Receive a Nerve Block: Contraindications

The surgeon will guide you and let the anesthesiologist know if a nerve block could be beneficial to you. Then, your anesthesiologist will review your medical history, type of surgery, and speak with you about the block.

After hearing the benefits and risks of a nerve block, it is ultimately up to you to decide whether or not you want this procedure to be performed. I don’t anticipate this happening, but you should never feel pressured to have a nerve block placed for your surgery. The first contraindication to any procedure is patient refusal.

Besides patient refusal, there are some other instances in which a nerve block may not be indicated. Ultimately, this is an individual anesthesiologist’s decision. These situations include active infection or sepsis, bleeding disorders, and peripheral neuropathy (or extremities that are already numb from a chronic medical condition).

Tips for Post-Op Care

Remember that a nerve block will cause part of your leg or arm to be “asleep.” So you will need to be careful with this extremity and make sure you don’t bump into anything. If you have had shoulder surgery, your arm will probably be in a sling. And if you have had hip, knee, ankle, or foot surgery, please use caution when standing up for the first time. You may feel that your nerve block has worn off, but your muscles may still be weak, and you could fall.

Also, your nerve block will eventually wear off. When you start to get the feeling that your block is subsiding, make sure to go ahead and take pain medicine. If you wait until the block completely wears off, and you haven’t taken any pain medicine, you may get behind on pain control.

Parting thoughts:

If you are having extremity surgery, a nerve block may be beneficial to alleviate post operative pain and aid in the recovery process. If so, we hope this information will lessen any fear you have about nerve blocks. And use this information as a starting point to discuss regional anesthesia techniques more knowledgeably with your anesthesiologist.

If you’ve had any experiences, good or bad, with regional anesthesia or nerve blocks, we would love to hear from you below. And please ask any questions we didn’t answer above.

Thanks again for visiting anesthesiamyths.com and stay healthy!  Feel free to leave a comment below or visit our forum for more discussion.

Dr. Joe