To evaluate the efficacy and safety of liposomal bupivacaine for postoperative analgesia in patients undergoing open tension-free inguinal herniorrhaphy (Lichtenstein repair) via ultrasound-guided transversus abdominis plane block (TAPB).

A prospective, single-center, randomized, double-blind, positive-controlled clinical trial was conducted. Eighty-two patients scheduled for unilateral Lichtenstein herniorrhaphy in the Second Department of Gastrointestinal Surgery, Tianjin Nankai Hospital between May 2024 and March 2025 were enrolled. Using block randomization, patients were assigned to one of three groups: Group A (20 ml sterile water for injection), Group B (10 ml 7.5 mg/ml hydrochloride bupivacaine+10 ml normal saline), and Group C (10 ml 13.3 mg/ml liposomal bupivacaine+ 10 ml sterile water for injection ). Resting pain scores (using the numeric rating scale method) were assessed 14 times at 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 36, 48, 72, and 96 hours postoperatively, and pain profiles were plotted. The cumulative burden of pain scores [area under the curve (AUC)], opioid drugs consumption, and incidence of adverse reactions during the 0-96-hour postoperative period were compared.

No statistically significant differences were observed in preoperative general characteristics among the three groups (P>0.05). The AUC in Group C (172.18) was significantly lower than that in Group A (233.42, P<0.001) and Group B (228.90, P<0.001), whereas no significant difference was found between Group A and Group B (P=0.752). Among the three groups of patients, Group C had the lowest rescue medication rate, with a statistically significant difference (P<0.05). The time to first rescue medication in Group C was significantly longer than that in Groups A and B. Group C had better postoperative pain control effect, and a higher proportion of patients did not require rescue medication. The incidence of postoperative analgesic-related adverse events has no significant difference among the three groups (P>0.05).

Preoperative administration of liposomal bupivacaine under ultrasound- guided TAPB effectively alleviates pain after open tension-free herniorrhaphy, with superior efficacy compared to conventional bupivacaine and a comparable safety profile.