Transmuscular quadratus lumborum versus transversus abdominis plane block for postoperative analgesia in unilateral inguinal hernia repair: A randomised controlled non-inferiority study

Background and Aims: Open inguinal hernia repair often causes significant postoperative pain. While the transversus abdominis plane block (TAPB) is widely used, the transmuscular quadratus lumborum block (QLB) may offer broader analgesia, but evidence is limited. This RCT evaluated whether QLB is non-inferior to TAPB in terms of duration of analgesia, opioid use, and pain scores in adults undergoing unilateral open inguinal hernia repair. Methods: This randomised trial was conducted in 70 patients, aged 18–60 years, of either gender, undergoing unilateral open inguinal hernia surgery under spinal anaesthesia. Patients were randomly assigned to receive either a transmuscular QLB or TAPB at the end of the procedure. The primary outcome was duration of analgesia; secondary outcomes included total opioid consumption in 24 h, visual analogue scores (VAS) at various intervals, haemodynamic parameters, and complications. Non-inferiority was tested using a one-sided t -test with predefined margins; P < 0.05 was considered significant. Results: QLB was found non-inferior to TAPB for the time of the first rescue analgesic request [mean difference (MD): 31.5] [standard deviation (SD): 360.4] [95% confidence interval (CI): −40.3, 103.4]; non-inferiority margin: −60 min)], and total tramadol consumption at 24 h [(MD: −11.4) (SD: 150.6) (95% CI: −41.4, 18.0); non-inferiority margin: 25 mg)]. There was no significant difference in postoperative VAS scores and haemodynamic parameters between the two groups. Conclusion: Transmuscular QLB was non-inferior to TAPB for postoperative analgesia in unilateral open inguinal hernia repair, though results should be interpreted cautiously due to residual spinal anaesthesia and variability.