Overview of Peripheral Nerve Blocks
There have been quite a few innovations in surgery recently, and many of these are less invasive methods that can be done on an outpatient basis. This means patients can go home the same day they have the surgery. Along with these surgical improvements, there’s a need for advancements in pain relief techniques.
Research has shown that a way of controlling pain called peripheral nerve blocks is usually accepted well by patients and provides better pain relief in a specific area as compared to other ways like taking oral pain meds or using general anesthesia. So, in a nutshell, as surgical procedures are becoming less invasive and more efficient, methods for controlling pain post-surgery are also evolving.
Anatomy and Physiology of Peripheral Nerve Blocks
The human body’s structure and important markers can vary depending on the kind of nerve block procedure being done. A nerve block is a procedure that blocks nerve signals to a specific area of the body, usually to manage pain. This can involve different areas of the body, so the specifics can change for each common type of nerve block.
Why do People Need Peripheral Nerve Blocks
Peripheral nerve blocks are a form of treatment with no rigid rules around when they should be used. In general, doctors use them when common treatments don’t work or to sidestep the potential issues that can come with general anesthesia or oral medications. Here are some situations where peripheral nerve blocks might be the better choice:
- Patients who could potentially experience severe breathing problems associated with general anesthesia, a type of medicine used to put patients to sleep during surgery
- Patients who want to avoid taking medicine that affects their entire body
- Patients who can’t take or don’t get relief from taking medications orally (by mouth)
When a Person Should Avoid Peripheral Nerve Blocks
In some situations, a doctor can’t use peripheral nerve blocks, which are injections that help numb certain areas of the body. Reasons may include:
If a person is allergic to local anesthetics, the medicines used to numb an area.
If a person cannot stay still or follow instructions during the procedure, or if they don’t want the nerve block.
The doctor might also decide to delay or reconsider the nerve block under different conditions:
If there’s an active infection where they need to give the injection, it might be too risky.
If a person already has problems with their nerves in the area where the nerve block is supposed to go, the nerve block might make these problems worse.
Also, if a person has coagulopathies, which are conditions that can cause problems with blood clotting, or if they’re taking antithrombotic drugs, which prevent blood clots, a nerve block may be too dangerous. These conditions could lead to dangerous bleeding during or after the nerve block.
Equipment used for Peripheral Nerve Blocks
The tools your doctor uses will depend on the kind of procedure they’re doing. Here’s a list of the different tools they might use, based on the technique:
* For nerve stimulator guidance: Your doctor uses a special tool that can send an adjustable electric signal to a tiny needle. This needle has a very specific tube attached to it that can suck in (aspirate) and inject a numbing agent (local anesthetic). A wire connects the needle and a pad (electrode) and transmits an electrical pulse to stimulate your nerve.
* For ultrasound guidance: This involves the use of portable ultrasound machines. These machines have both high and low-frequency probes capable of spotting nerves that are either close to the surface or buried deeper in your body.
* For continuous catheter: There are several kits your doctor can use. These kits usually contain a needle and catheter, which is a small, flexible tube. In many cases, a standard kit used for epidural (a type of anesthesia) can also be used.
Who is needed to perform Peripheral Nerve Blocks?
The injection should be done by a medical expert who has plenty of experience and knowledge about the specific type of injection being given. It’s important that the person giving the injection knows exactly what they’re doing to help ensure it’s done correctly and safely.
Preparing for Peripheral Nerve Blocks
Before performing a nerve block, a procedure to numb a certain area of the body, the doctor will gather a complete medical history. They do this to identify any conditions that might affect whether the block should be done, like blood clotting issues or breathing problems. The doctor will also do a thorough physical check-up to see if you’re already having any numbness or weakness in the area where the block will be done. Research suggests that if you’ve already got these symptoms, there might be an increased chance of developing new issues after the block. After this assessment, the doctor will have a discussion with you about the benefits and possible risks of the procedure, and tell you about any specific care you might need while recovering.
If you’re having a nerve block before surgery, you should follow the same rules about eating and drinking as if you were having an operation. This is because you might need to be sedated if the block doesn’t work properly. Doctors also need to put in an intravenous (IV) line as there might be some complications, such as fainting spells, reactions to the local anesthetic, or an unexpected need for general anesthetic during the procedure.
How is Peripheral Nerve Blocks performed
To understand peripheral nerve blocks, let’s break them down into examples of the most common types. This will give you a basic idea of how they work, the procedures involved, and the purpose they serve. It’s important to remember that the specific method used depends on the particular nerve block being performed.
An interscalene block numbs nerve roots from the neck and upper and middle parts of the brachial plexus, which is a group of nerves that send signals from your spine to your shoulder, arm, and hand. For this procedure, you’ll lie flat on your back and turn your head away from the side being worked on. The doctor identifies certain landmarks on your body, places an ultrasound probe on your neck, and visualizes structures like arteries and veins. They then follow the nerves upward where at the C6 nerves of the brachial plexus can be seen in a vertical orientation. Then, a needle is inserted and directed towards the nerves, injecting a local anesthetic.
A supraclavicular block involves numbing your shoulder and can be performed with you lying flat and your head turned away from the side being worked on. The doctor locates your carotid artery and internal jugular vein using an ultrasound probe and then inserts the needle parallel to this probe. The needle will reach an area bordered by the first rib, your subclavian artery, and your brachial plexus where a local anesthetic is then injected. This region of your body controls sensations to the medial (inner) side of your forearm and hand.
An infraclavicular block numbs the nerves in the lower part of your shoulder, and can also help with pain in your arm. You’ll lie flat on your back and turn your head away from the side being worked on. Like in the supraclavicular block, the doctor identifies your axillary artery and adjacent nerves via ultrasound, then injects local anesthetic next to the artery.
Remember that the purpose of these blocks is to help control pain, and they are designed to be safe and effective. However, as with any medical procedure, there may be risks associated, and your anesthetist will discuss this with you beforehand. If at any time you have questions or concerns about your procedure, don’t hesitate to address them with your medical provider.
Possible Complications of Peripheral Nerve Blocks
The possible problems and discomforts you might experience depend on the type of nerve block you get. These might include: a nerve injury in the area where the nerve block was done (this isn’t very common, but can potentially happen in 8% to 10% of procedures), bleeding in the area of the nerve block, an allergic reaction to the medication used for the block, an infection, or a reduced sensation after the nerve block. The medicine which is used to numb the nerves can sometimes have effects on the whole body as well, but this is also not very common.
