Ultrasound-guided transverse abdominis plane block, ilioinguinal/iliohypogastric nerve block, and quadratus lumborum block for elective open inguinal hernia repair in children: a randomized controlled trial

Background and objectives: Ultrasound-guided ilioinguinal/iliohypogastric (II/IH) nerve blocks and transverse abdominis plane (TAP) blocks are widely used for postoperative analgesia in children undergoing inguinal hernia repair (IHR). Quadratus lumborum block (QLB) provides analgesia for both upper and lower abdominal surgery. Very few randomized controlled trials in children have assessed the efficacy of QLB in IHR. Thus, this study was designed to find the comparative effectiveness of QLB versus TAP and II/IH blocks in children undergoing open IHR.

Materials and methods: Sixty children scheduled for open IHR were randomly allocated in groups of 20 to receive either ultrasound-guided TAP block with 0.4 mL/kg of 0.25% ropivacaine, II/IH nerve block with 0.2 mL/kg of 0.25% ropivacaine, or QLB with 0.4 mL/kg of 0.25% ropivacaine. Anesthesia was standardized for all patients, and an experienced anesthesiologist performed the blocks after anesthesia induction.

Primary outcome: Time to first analgesia.

Secondary outcomes: Postoperative pain scores, intraoperative and postoperative opioid consumption, cumulative paracetamol usage, block performance time, and block-related complications.

Results: The median time to first analgesia was 360 (120), 480 (240), and 720 (240) min in the TAP block, II/IH block, and QLB groups, respectively; and was significantly longer in the QLB versus TAP (p<0.001) and II/IH (p<0.001) groups. The time to first analgesia was not significantly different between the TAP and II/IH groups (p=0.596). The mean postoperative tramadol consumption was 11 (12.7), 4 (7.16), and 3 (8) mg in the TAP, II/IH, and QLB groups, respectively (p=0.023); and it was lowest in the QLB group. No significant differences were found between the groups for other secondary outcomes.

Conclusions: QLB provides a prolonged period of analgesia and leads to decreased opioid consumption compared with TAP blocks and II/IH nerve blocks in children undergoing open IHR.

Trial registration number: CTRI/2019/09/021377.