Lack of Analgesic Effect Induced by Ropivacaine Wound Infiltration in Thyroid Surgery: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Surgical site infiltration with local anesthetic reduces analgesic requests in various types of surgeries. Because thyroid surgery may induce severe postoperative pain, we tested the hypothesis that ropivacaine surgical site infiltration would significantly decrease postoperative administration of morphine in patients undergoing thyroid surgery. METHODS: We performed a double-blind, placebo-controlled superiority trial to assess the efficacy of surgical site analgesia with ropivacaine (10 mL, 75 mg) performed at the end of thyroid surgery in adult patients. The primary end point was the proportion of patients not requiring IV morphine in the postanesthesia care unit. RESULTS: One hundred sixty-three patients completed the study, 85 in the placebo group and 88 in the ropivacaine group. The proportion of patients requiring morphine administration in the postanesthesia care unit (55% vs 53%, P = 0.80), the dose of IV morphine administered (5.6 ± 6.1 vs 5.5 ± 6.0 mg, P = 0.90), the total dose of opioids administered (expressed as oral morphine equivalent dose: 64 ± 27 vs 69 ± 29 mg, P = 0.20), and the visual analog pain scale over the first 24 hours were not significantly different between groups. The incidence of adverse events (36% vs 39%, P = 0.88), morphine-related adverse events (19% vs 17%, P = 0.84), serious adverse events (0% vs 2%, P = 0.50), and the patient satisfaction scores (9 ± 1 vs 9 ± 1, P = 0.70) was not significantly different between the 2 groups. CONCLUSIONS: Surgical site analgesia with ropivacaine at the end of thyroid surgery is not associated with any significant analgesic benefit.