The Effect of Caudal Ropivacaine and Morphine on Postoperative Analgesia in Total Laparoscopic Hysterectomy: A Prospective, Double-Blind, Randomized Controlled Trial.

Purpose: Multiple regional nerve blocks proved no additional benefit in total laparoscopic hysterectomy in multimodal analgesia, as postoperative pain may mainly originate from the vaginal cuff. Theoretically, caudal block can relieve pain from the vaginal cuff by a sacral spinal nerve block. We aimed to verify whether a caudal block with ropivacaine and morphine can achieve an analgesic effect without additional adverse effects after a total laparoscopic hysterectomy. Patients and Methods: Forty-eight patients undergoing total laparoscopic hysterectomy were randomly allocated to receive preoperative caudal block with 20 mL of mixture including 0.25% ropivacaine and 2 mg morphine (caudal block group) or sham block (sham group). The primary outcome was the postoperative 24 h cumulative sufentanil consumption. Results: Median (IQR) sufentanil consumption in the first 24 postoperative hours of the caudal block group and the sham group was 0.00 (0.00 to 0.05) μg/kg vs 0.13 (0.04 to 0.21) μg/kg, respectively, p < 0.001. The majority of patients felt that visceral pain was more intense than incisional pain at 1, 6, 12, and 24 h post-surgery in the sham group (95.8% at 1 h, 95.8% at 6 h, 95.8% at 12 h, and 75% at 24 h post-surgery). Compared to the sham group, the caudal block reduced visceral pain scores at rest and during movement at 1 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001) post-surgery. Intraoperative remifentanil consumption was significantly lower in the caudal block group than in the sham group (p = 0.004). There were no significant differences in other secondary outcomes between the two groups. Conclusion: A caudal block with ropivacaine and morphine could provide a satisfactory analgesic effect for 24 h postoperatively without additional adverse effects after total laparoscopic hysterectomy.