Opioids have many side effects, such as constipation, urinary retention, itchy skin, respiratory depression, and postoperative nausea and vomiting. These side effects can lead to delayed recovery, longer hospital stays, and increased health care costs. Opioid-free anesthesia is the combination of anti-nociceptive drugs to block the different pathways involved in the transmission of nociceptive information, control pain, avoid opioid-related adverse reactions, and promote patient recovery. At present, opioid-free anesthesia is not widely used in craniocerebral surgery in neurosurgery, and the relevant clinical data are extensive. Therefore, the investigators urgently need to conduct a randomized controlled study to provide clinical evidence for the efficacy and safety of opioid-free anesthesia in neurosurgical patients.

Data sharing plan: The deidentified participant data reported in this study could be made available to researchers upon approval by the corresponding author (Dr. Ruquan Han, ruquan.han@ccmu.edu.cn) immediately after publication. The reasonable request should provide a formal protocol for database use that has been approved by the ethics institutions.

Inclusion Criteria:

• Scheduled to undergo craniotomy for supratentorial tumors with general anesthesia;
• 18 years≤age≤65 years;
• American Society of Anesthesiologists (ASA) physical status of I to III;
• Signed informed consent.

Exclusion Criteria:

• Patients with a body mass index (BMI)≥35 kg/m2;
• Patients with severe hepatic and renal insufficiency;
• Patients with cognitive dysfunction, aphasia and other states that do not cooperate with the assessment;
• Preoperative magnetic resonance imaging of the head showed midline displacement >5 mm;
• Patients undergoing electrophysiological monitoring during surgery;
• Pregnant or lactating patients.

Data sharing plan: The deidentified participant data reported in this study could be made available to researchers upon approval by the corresponding author (Dr. Ruquan Han, ruquan.han@ccmu.edu.cn) immediately after publication. The reasonable request should provide a formal protocol for database use that has been approved by the ethics institutions.