The purpose of this study is to evaluate the effectiveness of perioperative Lidocaine intravenous infusion in reducing postoperative pain for spine surgery patients.

Study design: this study used a prospective, randomized, double-blinded, and placebo-controlled clinical trial.

Sixty patients scheduled for a spine surgery will be randomly assigned to two groups. Lidocaine group will receive an intravenous bolus injection of lidocaine 1.5 mg/kg before intubation, followed by 2 mg/kg/h continuous infusion during the operation. Placebo group will receive the same dosage of saline at the same time. Analgesic requirement will be monitored using patient-controlled Analgesia (PCA protocol: demand dose is 2 mg of morphine, lockout 5 min, maximum dose 15 mg per hour). Forty-eight hours after surgery, we will check the morphine consumption in two groups. Quality of recovery after surgery will be assessed using Q0R15 questionnaire.

Inclusion Criteria:

• spine surgery with general anesthesia

Exclusion Criteria:

• lidocaine allergy
• hepatic disease
• dementia or cognitive decline