Methods: We performed a prospective double-blinded, randomized controlled trial that compared 3 parallel groups: the CONT group did not receive any block, the PRE group received bilateral superficial cervical plexus block before surgery while under general anesthesia, and the POST group received bilateral superficial cervical plexus block after surgery while under general anesthesia. The study included 111 patients (37 in each group). Postoperative pain was assessed every 4 hours by use of a 0 to 10 numeric rating scale. All patients received paracetamol every 6 hours. Morphine was administered following a standardized protocol if the numeric rating scale was 4 or higher. The main outcome variables were the proportion of patients given morphine during the 36 hours period, pain intensity scores, and morphine consumption.

Results: No intergroup differences were observed in terms of percentage of patients who required morphine, morphine delivery, pain scores, and intraoperative opioid consumption.

Conclusions: Bilateral superficial cervical plexus block with 0.75% ropivacaine administered before or after surgery does not improve postoperative analgesia after total thyroidectomy.