Randomized Comparison of Extrafascial Versus Subfascial Injection of Local Anesthetic During Ultrasound-Guided Supraclavicular Brachial Plexus Block

Injection of local anesthetic deep to the brachial plexus sheath at the supraclavicular fossa, under ultrasound-guidance, results in faster onset of surgical anesthesia and prolonged duration of postoperative analgesia than an injection superficial to the sheath.