Pilot Study for Posterior Quadratus Lumborum Block in Myomectomy: A Randomized Controlled Trial

Background: Uterine fibroids affect 20-40% reproductive age women in the United States. Gynecologic surgeons now perform roughly 65,000 myomectomies each year. The quadratus lumborum block (QLB) is an effective block for laparoscopic pelvic surgery, urologic surgery, hip hemiarthroplasty, femoral neck fracture repairs, and cesarean sections. No clinical trials have yet assessed the QLB in patients receiving laparoscopic myomectomies. We evaluated the effectiveness of the posterior QLB in reducing post-operative pain and morphine milligram equivalent (MME) consumption in patients undergoing laparoscopic myomectomies. Methods: This was a single center, single-blinded, randomized, controlled study conducted from February 5, 2019 and June 6, 2020. Twenty-seven patients undergoing laparoscopic myomectomy were enrolled, and randomized to the QLB group or control group. Patients in the QLB group received bilateral posterior QLBs. Patients in the control group did not receive a block. MME use at 24 hours following surgery was our primary outcome. MME at other timepoints, as well as post-operative numeric rating scale (NRS) pain score and patient satisfaction were our secondary outcomes. Results are presented as mean ± SD. Results: We recruited 26 patients, 21 of whom were included in our analysis. Total mean MME consumption was similar between the QLB group and the control group (24.7 ± 8.5 mg, vs. 26.8 ± 12.1 mg respectively; p=0.653). MME consumption was also similar among both groups for intraoperative consumption, total PACU consumption, and at 6, 24, and 48 hours after the end of surgery. Mean NRS pain scores were reduced at 6 hours postoperatively in the QLB groups compared to the control groups (2.0 ± 2.0 vs. 4.6 ± 2.3 respectively; p = 0.007). There was no difference in NRS pain scores at any other time point. Conclusion: This pilot study provides evidence the QLB may be useful in patients receiving laparoscopic myomectomies. Further studies with a larger sample size will be valuable to determine the effectiveness of this block in laparoscopic myomectomy. Trial Registration Our trial is registered with ClinicalTrials.gov on May 2, 2019 with the corresponding identifier NCT03935815