Forty ASA I or II patients, scheduled for aneurysm clipping were enrolled in this prospective, randomized, controlled study. Those patients were randomly divided into 3 groups: Group B (Scalp nerve block before skin incision n=15), Group I (Scalp infiltration before incision n=15), respectively with 0.75% of ropivacaine, and Group C (the control group, n=15). Opioids were used to control haemodynamic responses.All patients received the same general anesthesia.

After intubation, in group B, scalp block was performed by blocking the nerves that innervate the scalp, including the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater occipital and lesser occipital nerves, and skin along the incision was infiltrated with 0.75% ropivacaine (group I, n = 15), respectively. For group C, there is no treatment. All patients received the same general anesthesia. The depth of anaesthesia was adjusted to maintain a BIS of 40-60. Characteristics of patients were recorded. Heart rate (HR) and mean arterial pressure (MAP) were recorded preoperatively, after induction, before skin incision, the moment of incision, after skin incision. Plasma levels of IL-6, IL-10, CRP were measured before surgery, skin incision,after the surgery. Postoperative pain scores (VAS) for 2, 4, 8, 12, 24, 48 hours after recovery of consciousness were also recorded. Postoperative complications ( nausea, vomiting, infection, and other adverse events) were monitored after surgery.

For group B, the scalp block was performed bilaterally with 0.75% ropivacaine by the anesthesiologist. The supraorbital and supratrochlear nerves emerge from the orbit, and a needle was introduced above the eyebrow perpendicular to the skin with ropivacaine and was then gradually withdrawn with simultaneous injection of solutions throughout the entire. The zygomaticotemporal nerve emerge lateral to the orbit, equal to the position of pterion, this nerve was blocked with ropivacaine. The auriculotemporal nerve was blocked bilaterally anterior to the ear at the level of the tragus, the needle was introduced perpendicularly to the skin and infiltration was performed deep to the fascia and superficially as the needle was withdrawn. Care must be taken to avoid destroying superficial temporal artery. The greater, lesser, and third occipital nerves may be blocked using a needle, with infiltration along the superior nuchal line, approximately halfway between the occipital protuberance and the mastoid process.

For group I patients, neurosurgeons infiltrated the planned incision by a needle penetrated deeply to the skin with 0.75% ropivacaine throughout the entire thickness of the scalp.Neither scalp block nor local infiltration was performed in the control group (group C).

Inclusion Criteria:

• American Society of Anesthesiologists physical status I or II
• Glasgow coma score (GSC) of 15

Exclusion criteria:

• ASA physical status of more than II
• A ruptured cerebral aneurysm and subarachnoid haemorrhage
• A history of allergy to opiates or any other drug used in the study
• Impaired renal, hepatic, or pulmonary function
• Allergic reaction to local anesthetics