Methods:
A total of 122 patients who underwent lower abdominal or pelvic surgery in our hospital between March 2021 and July 2022 were selected and equally divided into OFA (F) and control (C) groups according to the random number table method. Both groups underwent ultrasound-guided unilateral/bilateral quadratus lumborum block in the supine position according to the surgical field. In group F, 0.50% lidocaine and 0.20% ropivacaine (in 20 mL of 0.9% normal saline) were injected on each side. In group C, 20 mL 0.9% normal saline was injected on each side. Group F received general anesthesia without opioids and group C received general anesthesia with opioids. BP, pulse oxygen saturation, P