Pain is common for the first 2 days after major craniotomy. A majority of patients would suffer from moderate-to-severe postoperative pain after undergoing craniotomy. Inadequate analgesia induced sympathetically mediated hypertension may lead to an increased risk for post-operative complications. Adequate pain control is essential for patients' prognosis and their postoperative life quality. Pain after craniotomy derives from the scalp and pericranial muscles. Local anesthetics administered around the incision have been performed clinically. However, some studies revealed that the analgesic effect of local anesthetics was not unsatisfactory due to its short pain relief duration. Pain is common for the first 2 days after major elective intracranial surgery, and the relatively short analgesic time of scalp infiltration does not seem to meet the requirements of craniotomy. Steroid such as triamcinolone acetonide as an adjuvant to local anesthetics intra-articular injected locally ameliorated pain intensity inarthroscopic knee surgery or total knee arthroplasty. However, there has not been reported about local application of triamcinolone acetonide on scalp infiltration. Thus, the investigators suppose that pre-emptive scalp infiltration with steroid (triamcinolone acetonide) plus local anesthetic (ropivacaine) could relieve postoperative pain after craniotomy in adults.

Inclusion Criteria:

• Patients scheduled for elective craniotomy for resection of tumour under general anaesthesia;
• American Society of Anesthesiologists (ASA) physical status of I ,II or III;
• Participates with an anticipated fully recovery within 2 hours postoperatively;

Exclusion Criteria:

• History of craniotomy;
• Expected delayed extubation or no plan to extubate;
• Participants who cannot use a patient-controlled analgesia (PCA) device;
• Participants who cannot understand the instructions of a numeral rating scale (NRS) 35 before surgery;
• Extreme body mass index (BMI) (< 15 or > 35);
• Allergy to opioids, triamcinolone acetonide or ropivacaine;
• History of excessive alcohol or drug abuse, chronic opioid use (more than 2 weeks), or use of drugs with confirmed or suspected sedative or analgesic effects;
• History of psychiatric disorders, uncontrolled epilepsy or chronic headache;
• Pregnant or at breastfeeding;
• Symptomatic cardiopulmonary, renal, or liver dysfunction or history of diabetes;
• Preoperative Glasgow Coma Scale< 15;
• Suspicion of intracranial hypertension;
• Peri-incisional infection;
• Participants who have received radiation therapy and chemotherapy preoperatively or with a high probability to require a postoperative radiation therapy and chemotherapy according to the preoperative imaging.