Comparison of the Efficacy of Single-Injection Regional Analgesia Techniques for Total Abdominal Hysterectomy: A Systematic Review and Network Meta-Analysis

Background: Single-injection regional analgesia techniques can provide effective analgesia for abdominal hysterectomy. However, few randomized controlled trials (RCTs) have directly compared these techniques for total abdominal hysterectomy (TAH), and the best strategy remains unknown. Objectives: In this network meta-analysis, we compared the analgesic efficacy of single-injection regional analgesia techniques in patients who underwent TAH. Study Design: A systematic review and network meta-analysis. Methods: We searched the PubMed, Embase, Cochrane, and CINAHL databases for relevant trials from inception until April 2022. RCTs that examined single-injection regional analgesia techniques for TAH were included. Random-effects network meta-analyses were performed using the frequentist approach. The primary outcome was 24-hour cumulative morphine equivalent consumption. The secondary outcomes were pain scores, time to first request for rescue analgesia, and rates of postoperative nausea and vomiting (PONV). Results: In total, 36 RCTs were included. Network meta-analyses indicated that the erector spinae plane block provided superior analgesia in terms of reduced morphine consumption, low PONV incidence, and longer time to first analgesia request. Moreover, compared with control (i.e., sham or placebo), the quadratus lumborum block provided superior analgesia in terms of time to first analgesia request and resting pain scores. Limitations: (1) Few studies have examined single-injection regional analgesia techniques other than the transversus abdominis plane block (TAPB) and wound infiltration, leading to a few indirect effect estimates. (2) Heterogeneity existed due to analgesic type/dose, plane block timing, and injection site. (3) Objective outcomes, such as length of hospital stay, were lacking; most studies only included the patient-reported subjective pain score. Conclusion: Single-injection blocks are effective analgesic techniques for TAH. Among them, the erector spinae plane block and quadratus lumborum block seem to have superior effects. Further studies should evaluate techniques other than TAPB and wound infiltration to draw definitive conclusions.