Chronic postoperative pain is one of the common perioperative complications, which seriously affects the prognosis of patients. Currently, no specific perioperative pain management strategy has been found to be effective in preventing and treating chronic postoperative pain in patients undergoing spinal surgery. At present, oxycodone has been widely recognized in different surgical populations for the control of acute postoperative pain, but its contribution to chronic postoperative pain remains unknown. Meanwhile, whether pregabalin can reduce the occurrence of chronic postoperative pain remains controversial, and whether the combination of the two drugs can control the occurrence of chronic postoperative pain in a more comprehensive way remains unknown. Therefore, we intend to conduct this randomized-controlled, factorial design study to determine the efficacy and safety of oxycodone combined with pregabalin in the treatment of chronic postoperative pain in patients undergoing spinal surgery.

Inclusion Criteria:

• Patient undergoing elective spinal surgery
• Ages equal to or more than 18 years old
• ASA I-III
• Signed informed consent

Exclusion Criteria:

• Previous allergic history to gabapentinoids or oxycodone;
• Patients with aphasia or inability to cooperate with scales assessments;
• Patients with a diagnosed history of psychiatric disorder;
• Known severe insufficiency of vitals(such as heart failure/renal dysfunction/hepatic failure);
• Patients treated with gabapentin/pregabalin in the last three months;
• History of drug abuse;
• Body Mass Index more than 35 kg/㎡;
• Pregnant or breastfeeding woman.