Overview of Infraclavicular Nerve Block
An infraclavicular block is a type of pain control method used instead of or alongside general anesthesia. This technique is typically used for controlling pain after surgeries on the upper parts of the arm, such as the hand, forearm, or elbow, but it’s not used for shoulder surgeries.
This type of block is a way to apply local anesthesia and was developed to avoid certain side effects and complications of a different technique called a supraclavicular block, which can lead to a collapsed lung, also known as a pneumothorax. A benefit of the infraclavicular block is that it has fewer complications when guided by ultrasound and fits well for the use of a catheter. On the flip side, it’s a bit of a tricky procedure to do, because the bundle of nerves, or brachial plexus, that it targets is located deeper inside, and the angle of approaching it is more direct. This makes it difficult to see the nerves and handle a needle at the same time, unless the doctor performing the procedure is quite experienced. The procedure can also be a challenge in patients who are obese for these same reasons.
The infraclavicular block was first described by Bazy in 1914, and Speigel detailed a related method in 1967. Then Raj introduced a new approach with better results using a nerve stimulator in 1973. Sims improved the technique again in 1976, making it more consistent and reliable using a fixed landmark on the body: the coracoid process, which is part of the shoulder blade. Since then, various other methods have been suggested, but today the most common approach is to use a sagittal scan at the lateral infraclavicular fossa, which is a small hollow space just below the collarbone on the side of the body.
Anatomy and Physiology of Infraclavicular Nerve Block
The brachial plexus is a network of nerves that transmits signals from the spine to the shoulder, arm, and hand. It is made up of nerve roots from C5 to C8 and T1. These nerves exit through openings in the spine and form three trunks (superior, middle, and inferior) that pass between the scalene muscles in the neck. Each trunk then divides into two divisions (anterior and posterior) behind the collarbone.
Underneath the collarbone, they form three cords – the lateral, posterior, and medial cords – which are named based on their position relative to the axillary artery, which supplies blood to the arm. These cords then split into five main nerves that control the muscles and feeling in the arm and hand.
The point where these cords appear beneath the collarbone is where an infraclavicular block (a type of nerve block used for arm and hand procedures) is performed. The axillary vessels (arteries and veins) and the cords of the brachial plexus sit deep under the chest muscles, positioned slightly downwards and inwards from the coracoid process (a small hook-like structure on the shoulder blade).
As the cords pass laterally (towards the side), they reposition themselves around the axillary artery, forming a kind of wrap around it. The boundaries of this area are shaped by several structures, including the chest muscles at the front, ribs at the side, the collarbone and coracoid process at the top, and the upper arm bone on the outer side.
Interestingly, the positioning of these cords can vary quite a bit from person to person. A study using MRI imaging has shown that these cords are typically positioned within 2 cm from the center of the axillary artery, forming about two-thirds of a circle around it. If you imagine a clock face with the axillary artery at the center, the cords are typically positioned between the 3 and 11 o’clock positions.
Why do People Need Infraclavicular Nerve Block
An infraclavicular block is a type of regional anesthesia or pain relief used during or after surgery on the hand, wrist, elbow, or lower part of the arm. This is a procedure that helps numb the upper extremity, making it suitable for various surgeries. However, it’s important to note that this method does not work for the shoulder area because it’s controlled by a different set of nerves known as the superficial cervical plexus C1 to C4.
If the surgery involves the skin under the arm or the upper inside part of your arm, you may need an extra nerve block, more specifically, an intercostobrachial nerve block, to ensure complete numbness. In some cases, the outer part of the lower arm controlled by the radial nerve might not be fully numb, which might result in slight sensation even after an infraclavicular block.
When a Person Should Avoid Infraclavicular Nerve Block
If you are in need of an infraclavicular block, a type of regional anesthesia often used for arm and hand surgeries, there aren’t any specific reasons you wouldn’t be able to have this procedure. However, there are a few conditions that might prevent you from having peripheral nerve blocks (which is a category infraclavicular blocks fall under):
1. If you don’t want to have the procedure (patient refusal).
2. If you are allergic to local anesthetics (the medicines used to numb the area).
3. If you have an infection where the injection would be given.
Moreover, there are also a couple of special conditions that might make doctors reconsider, or take special precautions, before doing a nerve block. These include:
1. Coagulopathy, a condition that makes blood clotting difficult. This increases the risk of bleeding during the procedure.
2. Preexisting active neurologic deficits, or pre-existing nerve damage, because the block might complicate these conditions.
Equipment used for Infraclavicular Nerve Block
The necessary equipment for this procedure includes:
Chlorhexidine gluconate or povidone-iodine: These are antiseptic solutions used to clean the skin and reduce the risk of infection.
High-frequency ultrasound probe with a sterile probe cover and gel: This device uses sound waves to create images of the inside of your body. It’s used to guide the procedure.
Sterile towels, gauze packs, sterile gloves, marking pen: These will be used to maintain a clean environment and mark the site for the procedure.
Local anesthetic like 1% lidocaine: This is a type of medicine that numbs the skin and tissues around the procedure area to minimize pain. It’s typically given with a small needle attached to a 3mL syringe.
Insulated-stimulating, block needle: This is a special needle used to deliver the local anesthetic. The size of this needle can vary, usually an 18-gauge needle is used for continuous catheter procedures and a 21-gauge needle for a single-injection.
Peripheral nerve stimulator (optional): This device may be used to locate and confirm the correct nerve for the anesthetic block.
Local anesthetic syringes: Two, 20-mL syringes will have local anesthetic for the block, which helps numb the area.
Regional block local anesthetic solution: This medicine provides pain relief after the procedure. The type of solution used might depend on how quickly pain relief is needed. Common options are 0.5% bupivacaine or ropivacaine for longer-lasting pain relief, or 2% lidocaine or 1.5% mepivacaine if quicker pain relief is necessary.
Intralipid 20%: This is used in case of Local Anesthetic Systemic Toxicity (LAST), a rare but serious reaction to local anesthesia.
Who is needed to perform Infraclavicular Nerve Block?
In performing an anesthesia procedure, the team includes medical workers who are trained in using ultrasound for specific areas. This task often entails two individuals. One person will be handling the ultrasound tool and needle, while the other will be responsible for managing the nerve stimulator and the syringe filled with local numbing medicines. Additional members of the team are necessary for closely watching the patient’s vital signs (body’s basic functions such as heart rate and breathing rate) and give emergency medications if required.
Preparing for Infraclavicular Nerve Block
Before starting the procedure, the doctor will attach devices to measure your heart rate (3-lead ECG), blood oxygen level (pulse oximeter), and blood pressure. The doctor will explain the procedure to you, and you will need to give your permission for it to go ahead – this is known as giving ‘informed consent’. Then, a final check is done to make sure everything is ready, this is called a ‘pre-procedure time-out’. You will lie flat on your back and look away from the side of your body where the procedure will take place.
Your arm can be in any position that is comfortable for you, but it might be best to bend your arm at the elbow and point your fingers to the ceiling – this can make it easier for the doctor to reach the area they need to. If a nerve stimulator is used during the procedure (a device that can make your hand twitch to see if the nerves are working properly), your wrist will be supported in a way that makes it easy to see the twitches.
Nerve stimulation can be uncomfortable, so you might be given a light sedative and painkiller to help you relax and make you more comfortable. You may also be given a fast-acting painkiller before the procedure begins, as the needle passing through the pectoralis muscle (the large muscle in your chest) can cause a bit of discomfort.
How is Infraclavicular Nerve Block performed
Over the years, health professionals have developed a variety of techniques for making injections or inserting needles. These techniques are based on different entry points on the body, landmarks on the surface of the body, and directions for the needle. The three methods that are most often used are called the coracoid method, the lateral- sagittal approach, and the vertical approach. There are also other techniques such as the parasagittal, pericoracoid, and retrograde methods.
In the coracoid method, the doctor first finds the coracoid process, which is a bony bump just inside of your shoulder. They do this by lifting and lowering your arm. The doctor also feels for the innermost head of your collarbone and then draws a line connecting these two points and marks the middle of this line. The needle is inserted 2-cm inside and 2-cm below the coracoid process and is directed from front to back. The cords that contain the nerves and blood vessels are usually around 4.5 cm deep.
For the parasagittal approach, the needle is inserted in the groove just below the collarbone and between the coracoid process and the collarbone. It’s then pushed from the upward to downward direction, reaching the cords 5 to 6 cm deep. To make it easier to find the right place, a sonogram, which uses sound waves to create a real-time image of the body, is used to see the pulse of a nearby artery.
The vertical infraclavicular block (VIB) method was developed by Kilka for managing pain in the upper arm. This method is straightforward, reliable, and safe because it uses well-defined landmarks on the body. In the original version of this method, the needle is inserted just beneath the middle of the collarbone at the midpoint of an infraclavicular line between the shoulder bone and the jugular fossa. The practitioner can use a sonogram to see the anatomy of the target area and to plan the best site for the puncture as well as the pathway.
Modern technology like ultrasonography, which provides real-time images of organs, blood flow, and tissues, has allowed for new research and techniques. For example, there are now modified versions of the VIB method, including the Greher’s and Neuberger’s modified VIB methods. These new modifications show how depending on the patient’s anatomy, the doctor can adjust the injection point for better results.
In 2004, Klaastad suggested an infraclavicular block using the lateral sagittal method can be done easily and with a low risk of complications. This method involves locating the coracoid process by moving a finger sideways below the collarbone. The needle is then inserted parallel to the bottom front edge of the collarbone and directed 15-degrees back to the front edge of the body.
Another method, the costoclavicular route, is becoming popular due to some limitations in other methods. This method is particularly good for providing effective pain control and safe anesthesia for surgeries on upper limbs and for vascular access. This technique is performed in the costoclavicular space, the gap located deep and behind the middle of the collarbone. This is between the clavicular head of the large chest muscle and subclavius muscle at the front and the second rib at the back. This space provides a clear view of the cords (bundles of nerves) of the brachial plexus that are closely positioned together by the side of the axillary artery. The use of a sonogram helps to guide the needle accurately to the desired spot with minimal discomfort to the patient.
Possible Complications of Infraclavicular Nerve Block
Getting a nerve block in the chest area, a type of pain relief, might have a few side effects. These effects can vary based on the method used and the amount of local anesthetic (pain-numbing medicine) given:
Some of the potential side effects include:
- Infection: this is when bacteria or other harmful organisms enter your body and make you sick
- Bleeding: if your blood does not clot well, there may be a risk of bleeding, especially with the ‘costoclavicular technique’
- Bruises or bleeding near surface areas under the skin, also known as a hematoma
- Damage to blood vessels, this takes place when the needle accidentally punctures a blood vessel
- Paresthesia, which is a feeling of ‘pins and needles’
- Nerve injury, which is damage to the nerves that can cause pain, weakness, or changes in sensation
- The numbness medicine could mistakenly be injected into a blood vessel, or directly into a nerve
- A serious condition called Local Anesthetic Systemic Toxicity (or LAST for short), when the local anesthetic enters the bloodstream, affecting the central nervous system and the heart
- Allergic reactions, which can cause rash, itching, or difficulty breathing
- Horner syndrome, a condition that can cause issues with your eyes and face
- Hemidiaphragmatic paralysis, a temporary inability to move one side of your diaphragm, which helps you breathe
- Pneumothorax, a collapsed lung
It’s important to remember that these side effects are not common and your healthcare provider will take steps to minimize any risks.
What Else Should I Know About Infraclavicular Nerve Block?
An infraclavicular brachial plexus block is a technique used to numb the area below the shoulder for surgery. It can be used as an alternative when other techniques, like supraclavicular and axillary blocks, aren’t suitable. For example, if a person cannot move their shoulder much, this type of block might be best. The infraclavicular area, just below the collarbone, is ideal for placing a tiny tube called a catheter, which helps deliver medicine to numb the area. This placement is stable and secure due to the location’s depth and the support of the chest muscles.
While this approach has not been as popular in the past because it’s difficult to visualize the target area, new techniques are helping to spark renewed interest. Compare this technique to the supraclavicular block (block delivered at the base of the neck) or the axillary block (block delivered in the underarm area), the quality of anesthesia for surgeries below the shoulder is found to be similar.
With advances in technology, such as ultrasound, the ability to better see and safely place the catheter for an infraclavicular brachial plexus block is improving. This is aiding in a better understanding of the benefits of this nerve block method for patients undergoing surgery below the shoulder.
