Anesthesia and postoperative analgesia
nerve block, pain
Following the nerve block, patients received general anesthesia administered by an anesthesiologist who was blinded to the allocation result. All the patients were treated with 10 mg of intravenous dexamethasone before surgery. For anesthesia induction, propofol (2.0–2.5 mg/kg), sufentanil (0.4–0.5 μg/kg), and vecuronium (0.1 mg/kg) were administered. Surgical interventions were performed by four teams of orthopedic surgeons using posterolateral approaches.During the operation, propofol (2–5 mg/kg/h), remifentanil (0.1–0.5 μg/kg/min), and sevoflurane (1–2% concentration) were used for anesthesia maintenance at the discretion of the anesthesiologist. The bispectral index (BIS) was maintained between 40 and 60, and the fluctuation ranges of invasive systolic blood pressure (ISBP) and heart rate (HR) were kept within 20% of the preoperative level.All the patients received 2 mg intravenous tropisetron at the end of the surgery, and patient-controlled intravenous analgesia (PCIA) was initiated before patients were sent to post-anesthesia care unit (PACU). The PCIA combination of drugs consisted of 800 mg of tramadol, 100 mg of flurbiprofen axetil, and 54 ml of normal saline, and with a total volume of 80 ml. The PCIA system was set to deliver 5 ml for the first dose, a background infusion rate of 1 ml/h, a patient-controlled dose of 2 ml, and a lockout time of 15 min. In addition to PCIA, the patients were treated with intravenous parecoxib sodium (40 mg per 24 h) for background pain control in the general ward during 48 h. Tramadol was administered orally for rescue analgesia when the pain score (VAS) ≥ 5, and the specific dose was evaluated by the ward surgeon.