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BLOCK AT A GLANCE
Block of the brachial plexus at the level of the supraclavicular fossa.
Indications: Anesthesia and analgesia for procedures on the shoulder, arm, elbow, forearm, and hand surgery
Goal: Injection of the local anesthetic (LA) around the trunks and divisions of the brachial plexus via two separate injections—one for the lower trunk (10 mL) and one between upper and middle trunk (10 mL)
Local anesthetic volume: 20 mL
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GENERAL CONSIDERATIONS
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The supraclavicular block is a commonly used technique for surgery of the upper extremity at or distal to the shoulder. As the trunks and divisions of the brachial plexus travel between the clavicle and the first rib, they are closely related to each other, therefore, affording supraclavicular block the fast, consistent, and complete block of the arm, forearm, and hand. Ultrasound (US) guidance has renewed the interest in the supraclavicular block due to its ability to visualize the plexus and avoid the vascular structures and the pleura. More precise needle placement using US allows better monitoring of the spread of LA and decreases the risk of complications caused by unintended pleural or vascular puncture. Different authors debate about the ideal position of the needle tip and the number of injections required. For instance, the so-called injection inside the “cluster” of neural structures has been reported to result in a faster onset than one injection deep to the brachial plexus (“corner pocket”). Some authors advise two separate injections (aiming at deep and superficial structures). However, considering that most studies show a similar success rate and that intracluster injection may carry a higher risk of intraneural injection, “intracluster” injection is not recommended.
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A selective block of the upper (superior) trunk with low volume of LA (5 mL) is an alternative to the interscalene block for shoulder surgery. Also, because the suprascapular nerve departs posteriorly from the upper trunk, a selective block of this nerve for analgesia of the shoulder without phrenic nerve involvement is possible (see Chapter 18).
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The risk of phrenic nerve block is lower than with the interscalene block, but cannot be reliably avoided. Therefore, in patients who cannot tolerate a 20-30% decrease in respiratory function as it occurs with a phrenic block, an infraclavicular approach to brachial plexus block is a better choice for upper extremity surgery or analgesia.
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Pneumothorax is an uncommon but potentially life-threatening complication because it is typically delayed and may occur in an unmonitored setting after discharge home. It is paramount to monitor the needle advancement at all times. Nerve injury to the plexus due to intraneural needle placement, or suprascapular and long thoracic nerve injuries have also been described. Routine use of US, nerve stimulation, and injection pressure monitoring is recommended.
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From a sagittal orientation in the interscalene ...