Superior Hypogastric Plexus Nerve Block in Minimally Invasive Gynecology: A Randomized Controlled Trial

Study objectiveTo assess the efficacy of a superior hypogastric plexus nerve block in reducing opioid requirements in the first 24 hours after minimally invasive gynecologic surgery.DesignPatient-blinded randomized controlled trial.SettingSingle-center academic institution (Sydney Women's Endosurgery Centre). Two surgeons administering the blocks in their own surgeries.PatientsPatients undergoing either laparoscopic or robot-assisted laparoscopic hysterectomy or myomectomy for benign indications.InterventionsRopivacaine 10 mL (0.75%) infiltrated into the retroperitoneal space overlying the superior hypogastric plexus vs control of no block given at the completion of surgery.Measurements and main resultsThe primary outcome was the total opioid use in the first 24 hours after surgery, measured in morphine milligram equivalents (MME). Standardized fentanyl patient-controlled analgesia was given to all patients in the trial. The secondary outcome was pain measured on a visual analog scale (1 to 10) at 1, 2, 6, 12, and 24 hours after surgery. Fifty patients out of 56 approached for the study participated in, and completed, the study (89.2%). The patients were randomized over a 5-month period, March 2020 to July 2020. A total of 27 patients were randomized to receive a nerve block, and 23 were randomized to the control. There was a difference of -21.8 MME in the block group compared with the no-block group (95% confidence interval [CI], -38.2 to -5.5; p = .008). This correlated to a 38% reduction in opioid use in the block group. The mean opioid use in the patients in the block group was 33.1 MME (95% CI, 24.2-41.9) and in those in the no-block group 54.9 MME (95% CI, 40.7-69.1). For the block group, opioid use ranged from 1.0 to 76.5 MME, with an interquartile range of 37 (14-51). For the control group, the range was 7.5 to 113.5 MME, with a higher interquartile range of 60 (28-88). Pairwise comparisons of the mean pain scores over the 24 hours showed a lower pain score with a nerve block of 1.8 (95% CI, 1.5-2.1) compared with a no-block score of 2.6 (95% CI, 2.3-2.9) No adverse effects of local anesthetic toxicity, nerve injury, or bowel/vascular injury were noted in any patient.ConclusionA superior hypogastric plexus nerve block is a simple technique for reducing postoperative opioid requirements and pain in the first 24 hours after minimally invasive gynecologic surgery.