When to Block? Timing of Scalp Block in Craniotomy

"Following induction of general anesthesia and prior to head pinning (Mayfield clamp placement), a scalp block was performed under aseptic conditions using 20 mL of 0.25% bupivacaine.~The block targeted six sensory nerves that innervate the scalp: Supraorbital nerve, Supratrochlear nerve, Auriculotemporal nerve ,Zygomaticotemporal nerve, Greater occipital nerve, Lesser occipital nerve.~Each nerve was infiltrated subcutaneously at its anatomical location using a 25-gauge needle, with the total volume distributed evenly or proportionally across the injection sites."

"In the pre-emergence group, the scalp block was performed at the end of surgery but before emergence from general anesthesia, while the patient was still under deep anesthesia.~Under strict aseptic conditions, 20 mL of 0.25% bupivacaine was administered to block the following six sensory nerves innervating the scalp: Supraorbital nerve, Supratrochlear nerve, Auriculotemporal nerve, Zygomaticotemporal nerve, Greater occipital nerve, Lesser occipital nerve.~The local anesthetic was injected subcutaneously at the anatomical landmarks of each nerve using a 25-gauge needle. The total volume was distributed evenly or proportionally depending on the area. No additional surgical stimulation occurred after the block, and extubation followed routine emergence from anesthesia."