To investigate the effects of ultrasound-guided anterior and posterior quadratus lumborum block (QLB) for analgesia after unilateral inguinal hernia repair surgery.

Sixty patients who underwent elective unilateral open inguinal hernia repair in Wuhu First People's Hospital from February 2020 to February 2022 were selected and randomly divided into anterior QLB group (group A) and posterior QLB group (group B), with 30 patients in each group. QLB was performed before general anesthesia induction. Sufentanil PICA was completed after the operation. Intramuscular injection of dezocine was given for remedial analgesia. Numerical rating scale (NRS) scores were recorded at 2, 6, 12, 24 h postoperatively at rest and when sitting up from the lying position. The first pressing time of analgesia pump, analgesia pump effective press number, the number of cases requiring remedial analgesia within 24 h, and VRS satisfaction score were recorded. The occurrence of lower limb muscle weakness, nausea and vomiting, drowsiness, hypotension and other adverse reactions and complications such as infection, visceral injury, hematoma, and local anesthetic poisoning were recorded.

The NRS score when sitting up from the lying position of group A was lower than that of group B at 12 and 24 h after surgery (P<0.05). The proportion of high satisfaction in group A was significantly higher than that of group B (P<0.05) at 48 h after operation. The first pressing time of the analgesic pump, the number of effective pressing of the analgesic pump, the number of 24 h remedial analgesia cases, and the incidence of nausea and vomiting in group A were significantly lower than those in group B (P<0.05). There was no statistically significant difference in the incidence rates of hypotension, muscle weakness, and drowsiness between the two groups (P>0.05). There were no complications such as infection, visceral injury, hematoma, and local anesthetic poisoning in the two groups.

For patients undergoing unilateral inguinal hernia repair, the analgesic effect of anterior QLB under ultrasound guidance is better than that of posterior approach.