Randomization and blinding
ESPB
The anesthesiologist in charge of intraoperative management evaluated the patients on the day before the operation and allocated them to the ESPB or control group based on a 1:1 random number (SPSS Statistics 26.0, IBM, USA). Standard general anesthesia was conducted in the two groups. The ESPB group received T12 ESPB after intubation, whereas the control group did not receive the intervention. T12 ESPB was performed by a specialist who was experienced in nerve blocks. Patients, postoperative physicians and postoperative investigators were unaware of the group assignments throughout the trial.