*2.2.9 Regional anesthesia*

Regional anesthesia offers perioperative analgesia and facilitates smooth emergence. Harvey, Cushing, and George Crile, first described the role of local anesthetic infiltration or regional anesthetics of the scalp for craniotomies in the early 1900s [54]. Girvin et al. first described the scalp nerve block technique in 1986 for use during awake craniotomy. It comprises of blocking six nerves that provide the sensory innervation of the scalp, on either side of the scalp, with infiltration of local anesthetics (2-3 ml) for each nerve. These nerves consist of the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, lesser occipital, and greater occipital nerves, usually given bilaterally. Scalp block effectively blunts the hemodynamic response preoperatively. Also, scalp block has been proven to be superior over a sham group (with saline) in terms of hemodynamic stability and decreased anesthetic requirement during cranial fixation [55, 56]. Scalp block's effect also extends into the postoperative period and has proved to decrease the incidence and severity of postoperative pain [57]. In summary, the incorporation of regional anesthesia has led to a smooth intraoperative course and improved postoperative patient comfort.
