Posterior Quadratus Lumborum Block Versus Posterior Transversus Abdominis Plane Block for Unilateral Inguinal Hernia Surgery

Background: Ultrasound-guided truncal nerve blocks are increasingly used for postoperative pain relief after abdominal surgery. Aim: The aim of this prospective and randomized study was to compare posterior transversus abdominis plane block (pTAPB) with posterior quadratus lumborum block (pQLB) for postoperative analgesic efficacy in patients undergoing unilateral inguinal hernia surgery under general anesthesia (GA). Patients and Methods: A total of 90 adult patients were randomized into 3 groups: group pTAPB (n = 30), group pQLB (n = 30), and group Control (n = 30). The patients in groups pQLB and pTAPB received a unilateral block using 20 ml of 0.25% bupivacaine after the induction of GA. Intravenous (IV) tramadol patient control group analgesia (PCA) and paracetamol were used in the postoperative period as a part of the multimodal analgesic regimen in both groups. Postoperative pain was assessed using a visual analog scale (VAS) during postoperative 24 h. Dexketoprofene was used as a rescue analgesic when VAS is >3. The primary outcome measure was mean pain scores. Secondary outcome measures were consumption of rescue analgesics and the amount of tramadol delivered by PCA. P <0.05 was considered statistically significant. Results: Mean VAS scores were significantly lower in the group pQLB than group pTAPB and group Control at all-time points (pQLB < pTAPB < Control; P < 0.001). Rescue analgesic was not required in group QLB. Rescue analgesic consumption, the number of bolus demand on PCA, and total PCA dose were highest in group Control and lowest in the pQLB group (Control > pTAPB > pQLB; P < 0.001). Conclusion: It is concluded that both pQLB and pTAPB provided effective pain relief after unilateral inguinal hernia surgery. pQLB was superior to pTAPB due to lower pain scores and analgesic consumption.