Interscalene Block
- The most proximal approach, the interscalene block is performed as the brachial plexus courses in the groove between the anterior and middle scalene muscles, traditionally at the level of the cricoid cartilage.
- Advantages of this block include rapid and reliable blockade of the shoulder region as well as relative ease of landmark palpation.
- Disadvantages of this block traditionally include incomplete coverage of the inferior trunk of the plexus; hence, insufficient anesthesia of the ulnar distribution makes it an unreliable block for forearm or hand procedures.
Supraclavicular Block
- A supraclavicular approach to the brachial plexus provides profound anesthesia to the entire arm, making it an appropriate block for most upper extremity procedures.
- Advantages include a compact formation of the plexus at this level and resultant dense blockade of the entire upper extremity.
- Disadvantages include the remote risk of pneumothorax and potential for slower block onset.
Infraclavicular Block
- The infraclavicular (or coracoid) approach is more distal still, at the level of the cords as they course circumferentially around the subclavian artery, providing dense anesthesia to the entire arm to the fingers.
- Advantages : The consistent anatomic relationship between the cords and the vascular structures makes it a predictable and reliable block to perform under ultrasound guidance. The lower anatomic location of this block makes it unlikely to encounter phrenic blockade and therefore makes it a more appropriate block for bilateral procedures.
- Disadvantages : Concern does exist that if the subclavian artery is accidentally punctured in the infraclavicular approach, subsequent compression of the area to tamponade bleeding is difficult.
Axillary Block
- The axillary block, the most distal of the brachial plexus blocks before the nerves leave the sheath and divide into their terminal branches, is perhaps one of the oldest and most traditional regional blocks for hand and wrist surgery.
- Disadvantages :
- Because the musculocutaneous nerve frequently leaves the sheath proximal to the intended insertion point of this block, frequently a supplemental injection into the body of the coracobrachialis muscle is needed, especially if a forearm tourniquet is planned.
- Major risks for this block are largely related to the close proximity of the axillary artery.
- Risks for minor bruising, tenderness and hematoma.
- Another concern relating to the high vascularity of this area is local anesthetic and systemic toxicity.
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