Background: This prospective, randomized, observer-blinded study compared ultrasound guidance and the conventional landmark-based technique for superficial cervical plexus blockade.

Methods: 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.

Results: 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.

Conclusions: Ultrasound guidance does not increase the success rate of superficial cervical plexus block compared with a landmark-based technique. Additional confirmatory trials are required.