Perioperative Multimodal Analgesia Protocol for Supratentorial Craniotomy

The 200ug dexmedetomidine will be diluted into a 50ml syringe and administered with 0.4ug/kg/h intraoperatively and 0.05 μg/kg/h for 48 hours after surgery.

In the placebo group, the 0.9% saline is administered with the same volume at the same speed as the dexmedetomidine group

The 10ml 1% ropivacaine will be diluted into a 20ml syringe . As for scalp nerve block, each nerve will be blocked separately with 1-2 mL 0.5% ropivacaine.

No Local analgesic techniques will be given.