Brachial Plexus nerve block

BRACHIAL PLEXUS BLOCK-
Techniques-
  • Interscalene Brachial Plexus Block
  • Supraclavicular(Subclavian)Brachial Plexus Block
  • Infraclavicular Brachial Plexus Block
  • Axillary Brachial Plexus Block
1. INTERSCALENE BLOCK:
Indications
-
  • Surgery in shoulder ,upper arm and forearm.
  • Post operative analgesia for total shoulder arthroplasty
  • Blockadge occurs at the level of the upper and middle trunks.
Positioning-
  • Supine position with the head turned away from the side to be blocked.
  • The posterior border of the sternocleidomastoid muscle is palpated by having the patient briefly lift the head.
  • The interscalene groove can be palpated by rolling the fingers posterolaterally from this border over the belly of the anterior scalene muscle into the groove.
  • A line extended laterally from the cricoid cartilage and intersecting the interscalene groove indicates the level of the transverse process of C6.
  • The external jugular vein often overlies this point of intersection.
TECHNIQUE-
  • Under sterile precautions and development of a skin wheal, a 22- to 25-gauge, 4-cm needle is inserted perpendicular to the skin at a 45-degree caudad and slightly posterior angle. The needle is advanced until paresthesia is elicited.
  • If bone is encountered within 2 cm of the skin, it is likely to be a transverse process, and the needle may be “walked” across this structure to locate the nerve.
  • After negative aspiration, 10 to 40 mL of solution is injected incrementally, depending on the desired extent of blockade.
  • Contraction of the diaphragm indicates phrenic nerve stimulation and anterior needle placement; the needle should be redirected posteriorly to locate the brachial plexus.
  • Interscalene approach to brachial plexus block does not provide optimal surgical anaesthesia in the area of distribution of ulnar nerve
Complications-
  • Ipsilateral diaphragmatic paresis
  • Severe hypotension and bradycardia (i.e., the Bezold-Jarisch reflex)
  • Inadvertent epidural or spinal block
  • Nerve damage or neuritis
  • Intravascular injection with Seizure activity
  • Horner’s syndrome with dyspnea and hoarseness of voice.
  • Puncture of the pleura may cause Pneumothorax.
  • Hemothorax.
  • Hematoma and Infection.
  • Distal root of plexus such as ulnar nerve block is spared
2.  SUPRACLAVICULAR BLOCK:-
Indications-
  • operations on the elbow, forearm, and hand. Blockade occurs at the distal trunk–proximal division level.
Location-
  • The three trunks are clustered vertically over the first rib cephaloposterior to the subclavian artery. The neurovascular bundle lies inferior to the clavicle at about its midpoint.
 Technique-
  • In supine position with the head turned away from the side to be blocked.
  • The arm to be anesthetized is adducted, and the hand should be extended along the side toward the ipsilateral knee as far as possible.
  • In the classic technique, the midpoint of the clavicle is identified . The posterior border of the sternocleidomastoid is felt. The palpating fingers can then roll over the belly of the anterior scalene muscle into the interscalene groove, where a mark should be made approximately 1.5 to 2.0 cm posterior to the midpoint of the clavicle. Palpation of the subclavian artery at this site confirms the landmark.
  • After appropriate preparation and development of a skin wheal, the anesthesiologist stands at the side of the patient facing the patient's head.
  • A 22-gauge, 4-cm needle is directed in a caudad, slightly medial, and posterior direction until a paresthesia is elicited or the first rib is encountered.
  • If a syringe is attached, this orientation causes the needle shaft and syringe to lie almost parallel to a line joining the skin entry site and the patient's ear.
  • If the first rib is encountered without elicitation of a paresthesia, the needle can be systematically walked anteriorly and posteriorly along the rib until the plexus or the subclavian artery is located .
  • Location of the artery provides a useful landmark; the needle can be withdrawn and reinserted in a more posterolateral direction, which generally results in a paresthesia or motor response.
  • On localization of the brachial plexus, aspiration for blood should be performed before incremental injections of a total volume of 20 to 30 mL of solution.
  • Complications
  • Pneumothorax, phrenic nerve block (40% to 60%), Horner's syndrome and neuropathy.
3. INFRACLAVICULAR BLOCK:-
Indications-
  • Hand, wrist, elbow and distal arm surgery
  • Blockade occurs at the level of the cords of the musculocutaneous and axillary nerves.
  • Anatomical landmarks: The boundaries of the infraclavicular fossa are
  • Pectoralis minor and major muscles anteriorly,
Ribs medially ,
  • Clavicle and the coracoid process superiorly,
  • Humerus laterally.
Technique-
  • Classic approach :The needle is inserted 2 cm below the midpoint of the inferior clavicular border, advanced laterally and directed toward the axillary artery
  • Coracoid technique: consisting of insertion of the needle 2 cm medial and 2 cm caudal to the coracoid process has also been described
4. AXILLARY BLOCK:-
  • Indications –
  • Include surgery on the forearm and hand. 
  • Elbow procedures are also successfully performed with the axillary approach.
  • Blockade occurs at the level of the terminal nerves. 
  • Blockade of the musculocutaneous nerve is not always produced with this approach.
Landmark-
  • The axillary artery is the most important landmark; the nerves maintain a predictable orientation to the artery. The median nerve is found superior to the artery, the ulnar nerve is inferior, and the radial nerve is posterior and somewhat lateral
  • At this level, the musculocutaneous nerve has already left the sheath and lies in the substance of the coracobrachialis muscle.
Technique-
  • The patient should be in the supine position with the arm to be blocked placed at a right angle to the body and the elbow flexed to 90 degrees.
  • A transarterial technique can be used whereby the needle pierces the artery and 40 to 50 mL of solution is injected posterior to the artery; alternatively, half of the solution can be injected posterior and half injected anterior to the artery.
  • Field block of the brachial plexus with a fanlike injection of 10 to 15 mL of local anesthetic solution on each side of the artery is a variation of the sheath technique.
Complications-
  • Nerve injury and systemic toxicity
  • Intravascular injection
  • Hematoma and infection are rare complications.
  • Persistent paresthesia of forearm is due to injury to the peripheral nerve (caused by alcohol contaminating the local anesthetic, sterilizing fluid contaminating the local anesthetic, nerve injury by the needle, hemorrhage in or around the neural sheath)

Exam Question
  • Interscalene approach to brachial plexus block does not provide optimal surgical anaesthesia in the area of distribution of ulnar nerve
  • Pneumothorax is a common complication of brachial plexus nerve block
  • Persistent paresthesia of forearm is due to injury to the peripheral nerve seen as complication of axillary nerve block

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