A Randomized Comparison Between Ultrasound-Guided and Landmark-Based Superficial Cervical Plexus Block

Abstract

This prospective, randomized, observer-blinded study compared ultrasound guidance and the conventional landmark-based technique for superficial cervical plexus blockade. Forty patients were randomly allocated to receive a block of the superficial cervical plexus using ultrasound guidance (n = 20) or the traditional landmark-based technique (n = 20). The main outcome, success, was defined as the absence of cold sensation for all 4 branches of the superficial cervical plexus at 15 mins. A blinded observer recorded success rate, onset time, block-related pain scores, and the incidence of complications. Performance time and the number of needle passes were also recorded during the performance of the block. Total anesthesia-related time was defined as the sum of performance and onset times. Success rate (80%-85%) was similar between the 2 groups. Performance time was slightly longer with ultrasonography (119 versus 61 sec, P < 0.001); however, no differences in onset and total anesthesia-related times were found. There were also no differences in the number of passes and procedural discomfort. Ultrasound guidance does not increase the success rate of superficial cervical plexus block compared with a landmark-based technique. Additional confirmatory trials are required.