Infraclavicular plexus block: vertical approach
COMPLEXITY:
Indications • Anaesthesia and analgesia for upper arm, lower arm, and hand surgery • Analgesia for physiotherapeutic treatment • Treatment of pain syndrome • Sympathicolysis.
Specifi c contraindications • Thorax deformity • Foreign bodies in the needle insertion area (e.g. pacemaker) • Clavicular malunion.
Side effects and complications • Intravascular injection • Pneumothorax • Horner’s syndrome. See Figures 3.20, 3.21, and 3.22.
Single injection technique Patient position: supine. Landmarks: acromion (ventral process) and clavicle. Technique: palpate the ventral process of the acromion. Make a mark 2 cm caudad and 2 cm medial to this point. Direct the needle sagittally, and advance approximately 3 cm (or to the same depth as the middle of the head of the humerus, depending on patient habitus). Correct placement of the needle will elicit fl exion of the fi ngers (median nerve) at a stimulating current of 0.3 mA/0.1 ms. Inject 30 mL of anaesthetic slowly. Needle: 22 G, 4–6 cm, short bevel. Local anaesthetic: 1.5% lignocaine (30–40 mL), 0.5% bupivacaine, or 0.75% ropivacaine. Comments: risk of pneumothorax. To avoid, do not insert the needle too far medially or deviate from the sagittal direction of insertion. Always perform this block using a nerve stimulator. If stimulation induces twitching of the biceps brachii muscle only, withdraw needle to a subcutaneous position; shift it slightly lateral, and re-advance it in a strictly sagittal direction. As the musculocutaneous nerve exits the brachial sheath before the coracoid process, twitching only of the biceps brachii muscle indicates incorrect needle placement and yields poor results. Stimulation of the median nerve yields the best results.
Continuous catheter technique Technique: locate the nerve as described above. Perform continuous catheter technique as described under Catheter technique for continuous infusions. Equipment: StimuCath™, or Plexolong or Contiplex ® (19.5 G, 3–6 cm, insulated Tuohy needle, and wire-stiffened 20 G catheter). Local anaesthetic: 0.2% ropivacaine.
Infraclavicular plexus block: vertical approach
COMPLEXITY: See Figures 3.23, 3.24, 3.25, and 3.26.
Ultrasound-guided technique Patient position: supine, with arm by side. To position the brachial plexus more superfi cially, abduct the patient’s arm over their head. Landmarks: surface: deltopectoral triangle; sonoanatomical: subclavian artery, vein, and nerve cords. Technique: place a linear array ultrasound probe in a lateral position at the deltopectoral triangle to obtain a SAX view of the plexus. The subclavian artery and vein, and the medial and lateral cords of the plexus, should be visible. To visualize the posterior cord (and the pleura), it may be necessary to tilt the probe obliquely. To anaesthetize each cord individually, insert the needle either superior or inferior to the probe, using an IP approach. Confi rm needle placement with a test dose of anaesthetic. Deposit 5–6 mL of anaesthetic around each cord. A ring of anaesthetic should be visible around each cord. Alternatively, the plexus may be anaesthetized without identifying and anaesthetizing each individual cord. Visualize the subclavian artery, and aim to deposit a U-shaped bolus superior, posterior, and inferior to the artery. The maximum total volume injected is 20 mL. Needle: 21–22 G, 9 cm, Stimuplex ® . Local anaesthetic: 1.5–2% lignocaine, 0.75–1% ropivacaine, or a 1:1 mixture of 2% lignocaine and 1% ropivacaine. Comments: the skin and pectoralis major muscle can be infi ltrated with anaesthetic prior to injection to increase patient comfort. It is not uncommon to see the posterior cord fused with another cord, most commonly the medial cord. Abducting the arm 110° and externally rotating the shoulder bring the brachial plexus more superfi cial and pleura anterior, thus care is required with needle insertion. Deposition of a U-shaped bolus under the subclavian artery is quicker and easier to perform than identifying and anaesthetizing each cord of the plexus individually. The target point for single injection technique or catheter placement is cephaloposterior to the artery. Local anaesthetic will displace the subclavian artery anteriorly if the correct U-shaped deposit is achieved. For continuous catheter techniques, place the catheter in the cephaloposterior quadrant behind the subclavian artery, adjacent to the posterior cord. In this quandrant, all three cords are in close proximity.
Infraclavicular plexus block: lateral approach
COMPLEXITY:
Indications • Anaesthesia and analgesia for the upper and lower arm, and hand surgery • Analgesia for physiotherapeutic treatment • Treatment of pain syndrome • Sympathicolysis.
Specifi c contraindications • Thorax deformity • Foreign bodies in the needle insertion area (e.g. pacemaker) • Clavicular malunion.
Side effects and complications • Intravascular injection • Pneumothorax.
See Figures 3.27 and 3.28.
Single injection technique 6 Patient position: supine, with the patient’s head turned away from the side to be blocked and arm abducted 90° and elevated 30°. Landmarks: jugular notch, acromion (ventral process), and axillary artery. Technique: palpate the jugular notch and the ventral process of the acromion. Insert the needle approximately 1 cm caudad to the clavicle at the midpoint between these landmarks. Direct the needle laterally at a 45–60° angle towards the most proximal point where the axillary artery can still be palpated in the axilla. Advance the needle 3–8 cm. Stimulation at this depth with a current of 0.2–0.3 mA/0.1 ms should elicit fl exion of the hand or fi ngers (median nerve). Inject 30 mL of anaesthetic slowly. Needle: 22 G, 6–10 cm, insulated. Local anaesthetic: 1% lignocaine (30–40 mL), 0.5% bupivacaine, or 0.75% ropivacaine. Comments: the risk of pneumothorax is low, as the needle is inserted and directed laterally.