A Low Approach to Interscalene Brachial Plexus Block Results in More Distal Spread of Sensory-Motor Coverage Compared to the Conventional Approach

A low approach to the interscalene block (LISB) deposits local anesthetic farther caudad on the brachial plexus compared with the conventional interscalene block (ISB). We compared the efficacy of LISB and ISB in achieving anesthesia of the distal extremity in 254 patients having upper extremity surgery. The most frequent elicited motor response was the deltoid for ISB and wrist for LISB. There was significantly greater sensory-motor block of regions below the elbow with the LISB compared with ISB (P < 0.001 for both sensory and motor coverage). Our data indicate that LISB results in a higher incidence of distal elicited motor response and greater sensory-motor blockage of the wrist and hand.