Overview of Brachial Plexus Block Techniques
Blocking the brachial plexus is a medical procedure that numbs the upper arm from the shoulder to the fingertips offering an effective anesthesia. The specific method used varies based on a few factors such as the patient’s body structure, medical history, individual anatomy, and the surgery or procedure being performed. This process can be performed in several ways such as the ultrasound-guided interscalene block, superior trunk block, supraclavicular brachial plexus block, infraclavicular brachial plexus block, and axillary brachial plexus block.
We now know that blocking the brachial plexus is a better way to manage pain after surgery compared to general anesthesia alone. If a fluid delivery system (catheter) is used to provide a continuous flow of anesthesia to the brachial plexus, this provides even better relief from pain and reduces the need for patients to take opioid pain relievers after upper arm surgeries. Also, it’s generally more effective to do this brachial plexus blocking procedure before shoulder surgery rather than during the operation.
Despite potential cost savings from solely using brachial plexus blocks instead of general anesthesia, these benefits only apply if general anesthesia isn’t needed as a backup plan. It’s crucial for the block to be placed and managed correctly to maintain cost-effective practices.
Properly placing the needle is critical for the block to work effectively. Ultrasound guidance helps doctors place the needle correctly. For best results, it’s important to understand the structure of the brachial plexus, which includes nerve roots, trunks, divisions, cords, and terminal branches. These structures should be seen clearly on the ultrasound before the injection is administered.
When performing this type of block, doctors should also account for the blood vessels in the area to avoid damaging them. Special imaging tools that show blood flow can help ensure that no blood vessels are punctured during the procedure.
In conclusion, blocking the brachial plexus can provide significant pain relief after upper arm surgeries compared to just using general anesthesia. However, to ensure the safety and effectiveness of this procedure, doctors need to have detailed knowledge of the structure of the brachial plexus and select the right method based on the patient’s specific characteristics. Precise needle placement and avoiding blood vessels are also essential considerations in this pain management procedure.
Anatomy and Physiology of Brachial Plexus Block Techniques
The brachial plexus is a network of nerves that starts from your neck, made from the C5 to T1 nerve roots, and travels down your arm. These nerves control the muscles of the shoulder, elbow, wrist, and hand, as well as providing feeling in the arm. Now, imagine the network is divided into three parts, with each part called a trunk. These are superior (C5, C6), middle (C7), and inferior (C8, T1) trunks. These trunks are located close to your collarbone or clavicle.
As these trunks continue down your arm, they split into three cords: the lateral (C5 to C7), posterior (C5 to T1), and medial (C8, T1) cords. These cords are located near a large blood vessel known as the axillary artery. Ultimately, these cords form several large nerves that control different parts of your arm and hand. These nerves are known as the median, ulnar, radial, and musculocutaneous nerves.
Understanding the path and location of these nerves is important because they can be targeted to block pain during some medical procedures. This is why your doctor could use different approaches such as the interscalene, superior trunk, supraclavicular, infraclavicular, and axillary methods.
The interscalene block is a common method that doctors use to numb the shoulder, arm, and forearm. This is done by applying a medicine around the brachial plexus in the neck.
The supraclavicular block is often used to reduce pain in the upper arm, and can be a great choice for procedures that involve the elbow and hand. In this method, the doctor inserts a needle just above the clavicle.
The infraclavicular block is used for surgeries involving the lower arm and hand. For this, the doctor inserts a needle near the collarbone, where the brachial plexus network meets the axillary artery.
Lastly, the axillary block is another approach used for operations involving the lower arm and hand nerves. Here, the doctor inserts a needle into the armpit and applies anesthetic to the brachial plexus network near the axillary artery.
Why do People Need Brachial Plexus Block Techniques
There are several techniques that doctors use to numb or block pain in your arm during surgery. They use local anesthesia to create these “blocks,” which essentially prevent pain signals from reaching the brain. Here, we’ll talk about a few different types of blocks.
The first is the interscalene brachial plexus block. This is a type of anesthesia that numbs the area from the end of the collarbone to the shoulder joint and the bone of the upper arm closest to the shoulder.
Then there’s the superior trunk block. This is a variation of the interscalene block that’s less likely to affect the nerve running to the diaphragm, which controls breathing. It provides pain relief to the shoulder area and the upper part of the humerus bone, which is the bone of the upper arm.
The supraclavicular brachial plexus block provides numbness or surgical anesthesia from the middle of the arm bone to the fingertips. This helps to ensure that you don’t feel any pain during a surgery in that area.
Next up is the infraclavicular brachial plexus block, which, like the supraclavicular block, provides numbness from the middle of the arm to the fingertips. It usually does not affect a particular nerve that runs in the armpit area, called the intercostobrachial nerve. This block can be performed with a traditional approach or a specific technique called the retroclavicular approach (RAPTIR).
Finally, the axillary brachial plexus block provides associated numbness from the mid-arm to the fingertips. It also usually doesn’t affect the intercostobrachial nerve. If necessary, this nerve can be easily blocked separately.
All these methods help in relieving pain during surgery and ensure comfort and painless surgical experience for you.
When a Person Should Avoid Brachial Plexus Block Techniques
There are certain circumstances where blocking the brachial plexus, a network of nerves located in the neck and shoulder area, may not be recommended. These include if there is an infection like cellulitis, a skin infection, or an abscess, a pocket of pus, at the place where the injection is to be given, or if a person is known to be allergic to the local anaesthetic used. As with any medical procedure, patients can always choose not to go ahead with it.
The use of an interscalene brachial plexus block, a specific type of nerve block, is not recommended in certain cases, such as certain lung and heart diseases. If a person is severely obese, it might be wise to avoid this type of block, as it could lead to trouble breathing due to potential paralysis of one side of the diaphragm, a muscle that helps us breathe.
Superior trunk blocks, another specific type of nerve block, have the same limitations as interscalene blocks. However, complications such as phrenic nerve palsy, a condition that interferes with nerve signals to your diaphragm, may occur less often. Please note that the dorsal scapular nerve is located nearby the typical injection site.
Supraclavicular brachial plexus blocks, a type of nerve block performed above the collarbone, should be used cautiously in patients with lung issues. For example, if someone has damaged lung function, any resulting pneumothorax, a punctured lung, could severely worsen their ability to breathe. This is particularly true if the patient already has pneumonia in the opposite lung.
Finally, axillary brachial plexus blocks, which are performed in the armpit, should be avoided if the path of the needle cannot be seen clearly through the densely blood-vessel-filled area.
Equipment used for Brachial Plexus Block Techniques
To carry out a procedure known as a brachial plexus block, which is a type of anesthesia used in the arm region, the doctor uses the following equipment:
A high-frequency ultrasound probe that is linear in form and has a frequency higher than 10 MHz. This helps to create pictures of the inside of your body so the doctor can guide the needle to the exact location.
A skin disinfectant solution made up of either 2% Chlorhexidine or povidone-iodine, which is used to clean the skin and reduce the risk of infection.
A local anesthetic to numb the area. The doctor choose the type of anesthetic based on how long they want it to work. For long procedures, they may use bupivacaine 0.5% or ropivacaine 0.5% while for shorter ones, lidocaine 2% or mepivacaine 1.5% might be used.
A syringe (10 mL to 20 mL size) with extension tubing, for injecting the anesthesia.
A short bevel block needle (10 cm, 18 to 22 G). This is a specific type of needle used for delivering the anesthetic.
A sterile ultrasound probe cover and sterile ultrasound gel. The cover keeps the probe clean and the gel improves the quality of the ultrasound image.
Standard vital sign monitoring equipment. This allows the doctor to monitor your blood pressure and heart rhythm, and maybe also your oxygen levels (using a device called a pulse oximeter), while the procedure is going on.
Who is needed to perform Brachial Plexus Block Techniques?
A health professional who is experienced in giving anesthesia using an ultrasound is needed for your procedure. The ultrasound helps them see where to give the medicine that numbs the area of your body where the surgery happens. Other staff members, like a nurse or another doctor, will also be there to keep an eye on how you’re doing. They can give you more medicine if you need it. Everything is done to make sure you are safe and comfortable.
Preparing for Brachial Plexus Block Techniques
Before any procedure that involves numbing the nerves of the upper arm, or what’s called a brachial plexus block, your doctor will explain the risks, benefits, and other alternatives to you so you could make an informed decision. Once you agree, the doctor will prepare for the procedure. They start by cleaning your skin with a disinfectant (chlorhexidine 2% or povidone-iodine) where they plan to inject you and then let it dry. A special gel is put on a probe (a device used to take pictures inside your body) to help get clear images. The probe is then covered with a sterile cover and more gel is added on top.
After this, they prepare a syringe with the right amount of local anesthetic, the medicine that numbs a part of your body. This syringe is attached to a tube and a special needle. They make sure there’s no air inside the needle or the tube to prevent complications during the procedure.
Different approaches can be used depending on the area of the arm to be worked on and they will position you accordingly. In most cases, you’re to lay on your back with your head turned slightly to the side opposite to the arm they’re going to work on. If they’re working on your shoulder and upper chest area, they might put a rolled towel under your shoulder to create some space and your arm is kept near your body.
But if they’re working on your armpit or lower chest area, your arm is raised to a right angle, this helps the doctor see the blood vessels easily and also guides the needle better. The doctor would do everything possible to ensure that you’re comfortable throughout the process.
How is Brachial Plexus Block Techniques performed
An interscalene brachial plexus block is a procedure done to numb a specific area of your body. It can be used for pain management or as anesthesia for surgery. Let’s break down the process step-by-step:
For this procedure, the doctor uses an ultrasound machine to have a clear view of the part of your body called the brachial plexus, which is a network of nerves that run from your neck to your arm. The ultrasound probe is set on your upper chest and guided down towards your chest cavity so the doctor can see this group of nerves on the screen.
Once the brachial plexus is identified, the doctor follows it upwards to find a particular spot known as the interscalene groove. Here, the nerves usually look like several circular structures that are not clearly visible (anechoic). The needle is carefully inserted in a way to avoid hitting any blood vessels, and to ensure it is not placed between these nerves.
The needle tip should be placed into the groove, and a small amount of local anesthetic is injected to make the area numb. The doctor will check for any signs of the anesthetic spreading into the blood vessels, which is not the intended effect. The amount of anesthetic used is usually between 10 to 30 milliliters (mL), depending on how much spread is seen.
There are different methods to numb your upper arm, such as Superior Trunk Block, Supraclavicular Brachial Plexus Block, Infraclavicular Brachial Plexus Block, and Axillary Brachial Plexus Block. Each method follows different steps, but all involve visualizing the group of nerves using ultrasound, inserting the needle at a specific angle, and injecting anesthetic.
The steps and details might be slightly different depending on the location and angle of injection. For all of these methods, the goal remains the same: To numb the targeted area in a safe and efficient way.
Possible Complications of Brachial Plexus Block Techniques
A nerve block is a type of medical procedure that is used to manage pain. However, sometimes it can lead to nerve damage due to factors such as accidental injection into the nerve, formation of a blood clot (hematoma), or damage caused by the needle used. Even so, recent research has found no connection between the type of nerve block used in the arm (brachial plexus block) and the chances of nerve damage.
The local anesthetic, which is the medicine used to numb the area, could sometimes have harmful effects if it enters the bloodstream. Therefore, doctors make sure to use a safe amount that’s less than the potentially harmful dose.
Additionally, each method of nerve block has its unique risks. For instance, the interscalene brachial plexus block, which is a specific type of nerve block done near the neck, could lead to weakness in the diaphragm on the same side, blood vessel damage, Horner syndrome (a nerve condition that impacts the face), spinal fluid block, and harm to the bunch of nerves in the arm (brachial plexus).
The superior trunk block, another type of nerve block, also poses the risk of weakening the same side of the diaphragm but perhaps less often. It could also injure the brachial plexus, blood vessels around it, or the dorsal scapular nerve that goes across the middle of the shoulder blade’s muscle.
The supraclavicular brachial plexus block that is done just above the collarbone carries the risk of a collapsed lung (pneumothorax) or puncturing the major blood vessel under the collarbone (subclavian artery). It could also lead to weakening one side of the diaphragm, but this risk is lesser than the interscalene block. If the anesthetic does not spread well, there can sometimes be incomplete numbness, especially in the ulnar nerve that runs along the inner side of the arm.
Complications of the infraclavicular brachial plexus block, done below the collarbone, can include injure to the brachial plexus, particularly the lateral and posterior cords, and harm to the axillary blood vessels. If the anesthetic does not spread well around the axillary artery, the medial cord leading to certain parts of the hand may not get numb. Furthermore, the needle can sometimes injure the artery and vein in the path.
Lastly, the risk of a collapsed lung is almost non-existent in the axillary brachial plexus block that is done at the armpit. To avoid accidentally puncturing a blood vessel and causing the anesthetic to enter the blood, doctors usually use a special ultrasound technique called color Doppler.
What Else Should I Know About Brachial Plexus Block Techniques?
Using ultrasound to help guide the delivery of medication blocks, we can numb the arm from the shoulder to the fingers. This more modern approach to handling pain relief makes the process safer and more precise. Evidence suggests that using ultrasound helps to decrease the amount of anesthetic required and lowers the risk of complications, like puncturing a lung or damaging blood vessels, while increasing the likelihood of success.
An area known as the interscalene brachial plexus can be targeted to manage severe pain connected to fractures in your shoulder or collarbone, as well as shoulders that have been dislocated. It is effective in controlling postoperative pain and decreases the need for painkillers in patients recovering from shoulder surgeries. In some cases, this method has been used as the single source of anesthesia in shoulder arthroscopy, a minimally invasive surgical procedure that examines and treats issues in and around the shoulder joint.
However, when using an interscalene block for shoulder pain, there is a higher risk of causing temporary paralysis on the same side of the body as the block (ipsilateral hemi-diaphragmatic paralysis) through damage to the phrenic nerve. In cases where this is a concern, an alternate method, like a superior trunk block, or a combination of a suprascapular and axillary nerve block might be considered. While the superior trunk block has potential to spare the diaphragm, more research is needed to confirm its effectiveness.
Several techniques can be used to numb the arm below the shoulder level, depending on the patient’s needs and a given set of factors, including the ability to position the patient correctly, any infection at the intended injection site, pre-existing blood clotting disorders, the operator’s skill level, and anatomical variations in the patient.
The combination of a suprascapular and axillary nerve block is an interesting alternative to regional anesthesia for shoulder surgery. This method may be preferable in patients with serious lung disease, obstructive sleep apnea, or severe obesity.
When comparing the effectiveness of the supraclavicular, infraclavicular, and axillary blocks, a recent deep-dive analysis found that all three were likely to successfully numb the area.