Transversus Abdominis Plane Block versus Quadratus Lumborum Block for Postoperative Pain in Abdominal Surgery: A Systematic Review and Meta-analysis

Regional anaesthesia for the prevention and minimization of postoperative pain aims to decrease postoperative pain, opioid consumption and patient controlled analgesia (PCA) requirements. Quadratus Lumborum (QL) blockade and Transversus Abdominis Plane (TAP) blockade are two options for regional anaesthesia following abdominal surgery. The aim of this systematic review was to compare the efficacy of QL versus TAP blockade for management of postoperative pain in abdominal surgery. A systematic review of 5 databases (Pubmed, Web of Science, SCOPUS, Medline and CINAHL) was performed. Studies comparing QL block to TAP block for postoperative pain management in abdominal surgery were included. The primary outcome was pain postoperatively. Secondary outcomes included time to rescue analgesia, adverse effects and morphine consumption. Four studies with a total of 188 patients were included in the final review. A significant reduction in postoperative pain was identified with QL blockade by -0.42 (95%CI= -0.67 to -0.17; I2= 94%; p=0.001). Two high quality studies showed a significant reduction in 24-hour morphine consumption when utilising QL blocks (13.63 mg; 95%CI= 1.48 to 25.78 mg; I2= 98%; p=0.03). However, this review identified no significant difference in time to breakthrough analgesia of 459.69 minutes with QL block (95%CI= -85.33 to 1004.71; I2= 100%; p=0.10). The incidence of adverse effects was similar between the two blocks. QL blockade leads to a significant reduction in 24-hour morphine consumption and postoperative pain scores, with no increase in adverse event rates. Therefore, QL blockade is likely a preferable regional analgesic technique to TAP blockade, but further large randomised controlled trials are required to confirm these findings.