Objective  To compare the application effects of ultrasound-guided transversus abdominis plane block (TAPB) and quadratus lumborum block (QLB) in laparoscopic surgery for patients with rectal cancer.

  Methods  A total of 94 patients with rectal cancer undergoing laparoscopic surgery were selected as research objects, and were randomly divided into observation group (n=47) and control group (n=47). The observation group was given ultrasound-guided QLB, and the control group was given ultrasound-guided TAPB. The dosage of sufentanil, the degree of pain Visual Analogue Scale (VAS) and the incidence of adverse reactions were compared between the two groups. The serum levels of 5-hydroxytryptamine (5-HT), substance P (SP) and prostaglandin E₂ (PGE₂) were compared between the two groups before and after operation.

  Results  At 2, 8, 12 and 24 h after surgery, the cumulative use of sufentanil in the observation group was significantly lower than that in the control group, and VAS score was significantly lower than that in the control group (P < 0.05). At 24 h after operation, the levels of 5-HT, SP and PGE₂ in both groups were significantly higher than those before operation, while those in the observation group were significantly lower than the control group (P < 0.05). The incidence of adverse reactions in the observation group was 10.64%, which was significantly lower than 27.66% in the control group (P < 0.05).

  Conclusion  Compared with ultrasound-guided TAPB, ultrasound-guided QLB has a better application effect in laparoscopic surgery for rectal cancer, which can effectively relieve postoperative pain, reduce the level of pain mediators and the incidence of adverse reactions, and reduce the use of other anesthetics.