Ultrasound-guided infraclavicular brachial plexus block: An alternative technique to anatomical landmark-guided approaches

Background and Objectives: Infraclavicular brachial plexus block has been used less than other approaches because of its less uniform landmarks and the necessity of a longer needle, which increases the patient's discomfort. To overcome these drawbacks, we applied ultrasound guidance to infraclavicular approach and prospectively evaluated its feasibility and usefulness in 60 patients undergoing upper extremity surgery. Methods: A 7.0-MHz ultrasound probe was placed near the lower edge of the clavicle, and a transverse view of the subclavian artery and vein was visualized. Using a needle guide, a 23-gauge needle was advanced under real-time ultrasound guidance, and 1.5% lidocaine with 1:200,000 epinephrine was injected near the subclavian artery, 15 mm medially and 15 mm laterally to the artery. The extent of sensory and motor block was evaluated at 30 minutes after the injection. Results: An adequate ultrasound image was obtained for all the patients. In 57 patients (95%), surgery was performed without supplementation of any other anesthetics or analgesics. The complete sensory block was obtained in 100% of patients for the musculocutaneous and medial antebrachial cutaneous nerves, 96.7% for the median nerve, and 95% for the ulnar and radial nerves. The complete motor block was achieved in 100% of patients for the musculocutaneous nerve, 96.7% for the median nerve, 90% fur the ulnar nerve, and 93.3% for the radial nerve. No evidence of any complications was identified. Conclusions: Real-time ultrasound guidance facilitates accurate infraclavicular approach to the brachial plexus. It could be used as an alternative to the landmark-guided techniques.