Introduction
The brachial plexus block is an efficient means of administering anesthesia to the upper extremities from the shoulder to the digits. The injection of local anesthetic drugs adjacent to the brachial plexus temporarily blocks sensation and movement of the upper limbs. There are several methods for blocking the brachial plexus, depending on the need for the block, the operation or treatment being performed, the patient's body habitus, associated complications, and individual anatomical variances. The individual can stay awake during the surgery, or they can be sedated or even fully asleep if required.
By providing total muscle relaxation, preserving hemodynamic stability, and the accompanying sympathetic block, the brachial plexus block is an ideal approach for achieving ideal operating parameters for upper limb procedures. They also offer prolonged postoperative analgesia with a few adverse effects. Furthermore, it gives excellent mental function restoration in the elderly; lowers the risk of aspiration due to preserved pharyngeal and laryngeal reflexes; avoids difficult intubation; reduces chances of postoperative difficulties associated with intubation; as well as delivers excellent postoperative analgesia without excessive sedation, allowing for early mobilization and discharge.
Many additives have been utilized, including opioids like Morphine, Fentanyl, Tramadol, Buprenorphine, and Sufentanil, as well as calcium channel blockers like Verapamil and alpha-agonists like Clonidine. Using steroids as a supplement to a local anesthetic medication in the brachial plexus block is becoming more common. Among many of the different techniques for brachial plexus block, the supraclavicular route is the most popular and effective procedure for operations below the shoulder joint.
What Is the Anatomy of the Brachial Plexus?
The C5 (cervical vertebrae) to T1 (thoracic vertebrae) nerve roots unite to form the brachial plexus. The superior (C5, C6), middle (C7), and inferior trunks (C8, T1) above the collarbone are formed by the union of these roots. Because the trunks travel beneath the collarbone, they are close to one another and can be readily blocked at this level. The plexus divides distal to the clavicle into the lateral (C5-C7), posterior (C5-T1), and medial (C8, T1) cords, which are located close to the axillary artery. Finally, the cords in the axilla give rise to terminal nerve branches.
The median nerve, created by the medial and lateral cords, is frequently found superficial to the axillary artery. The ulnar nerve arises from the medial cord and is often situated lateral to the axillary artery. The axillary artery is deep and lateral to the radial nerve. The last terminal branch, the musculocutaneous nerve, emerges from the lateral cord and penetrates the coracobrachialis (a muscle in the anterior compartment of the upper arm) in the proximal axilla.
What Are the Techniques Used for Brachial Plexus Block?
Blockade of the brachial plexus can be done at different points with varying impacts. Because of the differences in patient anatomy and indications, it is advantageous to be aware of numerous techniques.
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Interscalene.
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Supraclavicular.
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Infraclavicular.
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Axillary.
What Are the Indications of Brachial Plexus Block?
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Interscalene Brachial Plexus Block: It produces analgesia or surgical anesthesia to the upper limb from the collarbone, shoulder, and proximal humerus (upper arm bone) distal extremity.
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Supraclavicular Brachial Plexus Block: It anesthetizes the upper extremity from the middle of the humerus to the digits.
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Infraclavicular Brachial Plexus Block: It anesthetizes the upper extremity from the middle of the humerus to the digits. This block usually spares the intercostobrachial nerve. This block can be administered using either the usual method with a sharp needle angle or the retroclavicular approach.
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Axillary Brachial Plexus Block: This anesthetizes the upper extremity from the mid-humerus to the fingertip. Although it is readily blocked, this block preserves the intercostobrachial nerve.
What Are the Contraindications of the Brachial Plexus Block?
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Interscalene Brachial Plexus Block: Lung illness, cardiovascular disease, acute bacterial infection over the injection site, patient rejection, allergy to the local anesthetic. As respiratory insufficiency might develop in hemidiaphragmatic paralysis, severe obesity may be a relative contraindication.
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Supraclavicular Brachial Plexus Block: It causes wound infections at the injection site. Patients with sluggish pulmonary reserve should be treated cautiously since a pneumothorax might dramatically exacerbate their respiratory condition.
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Infraclavicular Brachial Plexus Block: Inflammation of the subcutaneous tissue at the site of injection.
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Axillary Brachial Plexus Block: Inflammation of the subcutaneous tissue at the site of injection.
How Is the Patient Prepared for Brachial Plexus Block?
Before executing the brachial plexus blocks, the patient must be informed of the therapy's risks, advantages, and substitutes. In addition, the patient has to provide informed permission for the treatment. Before the injection, the skin is washed and dried with a two percent Chlorhexidine or Povidone-iodine disinfectant solution. After applying sterile gel to the probe, a sterile probe cover with extra sterile gel is inserted outside the probe cover. The syringe is filled with the required volume of local anesthetic solution and connected to the extension tubes to a short bevel block needle. The air from the system is ejected to prime the tubes and needle; an air injection into the site will hinder exposure to ultrasound (insonation).
Interscalene, Superior Trunk, Supraclavicular, and Infraclavicular (Retrogressive) and Axillary Approaches: The patient is positioned lying face upwards with the head and neck moved slightly to the opposite side. If extra room is needed for needle manipulation, a towel roll is placed beneath the shoulder of the side to be performed.
For the Infraclavicular (Classic or Anterior) and Axillary Approaches: To maximize the visibility of the axillary artery and assist needle passage, the same side of the shoulder can be moved away from the midline of the body to 90 degrees with the elbow bent.
What Are the Complications of the Brachial Plexus Block?
All blocks are at risk for nerve injury (neuropraxia, neurotmesis) due to multiple factors, including inadvertent intraneural injection, local anesthetic neurotoxic properties, hematoma formation, and physical damage from the block needle. Local anesthetic systemic toxicity should also be considered as a complication for all blocks.
Conclusion
Brachial plexus block is a viable substitute to general anesthesia for many upper extremity treatments and a beneficial analgesic element for some of the more critical elective and emergency operations. By combining ease of use with efficacy, many clinicians would consider employing these techniques in everyday clinical practice.
