Prevention of postoperative pain after thyroid surgery: A double-blind randomized study of bilateral superficial cervical plexus blocks

Local anesthetic infiltration may reduce postthyroidectomy pain. We perform ed a double-blinded, randomized, placebo-controlled trial to assess the ana lgesic efficacy of bilateral superficial cervical plexus blocks performed a t the end of surgery. Ninety patients undergoing elective thyroid surgery b y the same surgeon under general anesthesia were randomized to receive 20 m t isotonic sodium chloride or 20 mt bupivacaine 0.25% with 1:200,000 epinep hrine. Postoperative pain was assessed every 4 h using an 11-point numeric rating scale (NRS-11). All patients received acetaminophen every 6 h. In ad dition, morphine was administered following a standardized protocol if the NRS-11 score was greater than or equal to4. The main outcome variables were pain scores (NRS-11), the proportion of patients given morphine at any tim e during the 24-h period, and the amount of morphine administered. The Bupi vacaine group had a smaller proportion of patients given morphine (66.0% vs 90.0%; P = 0.016), and lower initial median pain scores (P = 0.002). We co nclude that bilateral superficial cervical plexus blocks significantly redu ce pain intensity in the postoperative period after thyroid surgery but do not provide optimal pain relief alone.