The Analgesic Effect of Ultrasound-Guided Quadratus Lumborum Block After Cesarean Delivery: A Randomized Clinical Trial

BACKGROUND: Landmark and ultrasound-guided transversus abdominis plane blocks have demonstrated an opioid-sparing effect postoperatively after cesarean delivery. The more posterior quadratus lumborum (QL) might provide superior local anesthetic spread to the thoracolumbar fascia and paravertebral space. The aim of our study was to evaluate the efficacy of the QL block after cesarean delivery. METHODS: A randomized, double-blind, controlled trial was performed. Forty parturients undergoing cesarean delivery received bilateral ultrasound-guided QL blocks with either 2 mg/mL ropivacaine or saline postoperatively. All patients received spinal anesthesia with bupivacaine and sufentanil and a postoperative analgesic regimen of paracetamol, ibuprofen, and ketobemidone administered by a patient-controlled analgesic pump. The ketobemidone consumption and time of each dose administered were recorded. The primary outcome was ketobemidone consumption during the first 24 hours postoperatively. Secondary and exploratory analyses compared repeated measures of pain scores, nausea, and fatigue, and total differences in time until patients were able to stand and able to walk 5 m, and the interaction between the effective analgesic score and time. RESULTS: All 40 patients completed the trial, 20 in each group. The cumulative ketobemidone consumption in 24 hours was reduced in the active group compared with the control group (P = .04; ratio of means = 0.60; 95% confidence interval, 0.37-0.97). The effective analgesic scores were significantly better in the treatment group compared with the placebo group both at rest (P < .01) and during coughing (P < .01). CONCLUSIONS: QL block with ropivacaine reduces the postoperative ketobemidone consumption and pain intensity as a part of a multimodal analgesic regimen that excludes neuraxial morphine.