Post-craniotomy pain is common and often associated with poor outcomes. Flurbiprofen axetil (FA) is an injectable NSAID for postoperative analgesia, however, the impact of local FA, remains elusive on post-craniotomy pain. As FA is highly lipophilic by merging into emulsified lipid microspheres, it has a high affinity to the surgical incision and inflammatory tissues to achieve targeted drug therapy and prolonged duration of action. On base of the previous report that local NSAIDs achieved therapeutic tissue concentrations despite a plasma concentration of <5% of that of systemic administration, a low-dose of FA might be considered a preferential option for local infiltration to avoid anti-platelet related side effects, such as intra-cerebral bleeding. In this study, the investigators attempt to evaluate the clinical effects of pre-emptive scalp infiltration with low-dose FA and ropivacaine for postoperative analgesia after craniotomy.

Inclusion Criteria:

1. Age 18-64 years;
2. ASA physical status of I - II;
3. Scheduled for craniotomy under general anesthesia;
4. Anticipated tracheal extubation, recovery of consciousness and orientation within 2 hours after craniotomy.

Exclusion Criteria:

1. Glasgow Coma Scale <15;
2. Unable to use the PCIA device or comprehend the pain NRS;
3. History of opioid dependence, chronic headache or intake of any drugs with known analgesic properties within the 24 hours before surgery;
4. Any contraindication to flurbiprofen axetil, such as gastrointestinal ulcer, coagulation disorders, renal dysfunction, heart failure and ischemic heart disease;
5. History of allergy to any drug used in the study.