Aliste J, et al. - In this randomized trial, researchers compared ultrasound (US)–guided interscalene block (ISB) and small-volume supraclavicular block (SCB) for arthroscopic shoulder surgery, presuming that SCB would provide equivalent analgesia to ISB 30 minutes after surgery without the risk of hemidiaphragmatic paralysis (HDP). All patients undergoing an US-guided intermediate cervical plexus block were assigned to receive US-guided ISB vs US-guided SCB. Pain scores at rest at 0.5, 1, 2, 3, 6, 12, and 24 hours were recorded postoperatively by a blinded investigator. They found that small-volume SCB, vs ISB, provided equivalent postoperative analgesia and a lower incidence of HDP. They also noted that the latter could not be completely avoided with small-volume SCB.