Craniotomy involves multiple invasive steps (skull pin fixation, skin incision, dissection, bone drilling, skin closure) that trigger noxious stimuli, leading to abrupt increases in heart rate (HR) and mean arterial pressure (MAP), thereby raising cerebral blood flow (CBF) and intracranial pressure (ICP) [1]. In patients with impaired intracranial compliance or autoregulation, such changes may cause cerebral edema, hemorrhage, or herniation [2], [3]. Effective blunting of these responses is vital for cerebral homeostasis and patient safety. Postoperative pain, influenced by direct tissue trauma, inflammation, meningeal irritation, and central sensitization, is reported in up to 87 % of cases, with 70 % requiring opioids [4], [5]. However, opioids may cause excessive sedation, delay recovery, and impair early neurological assessment [6].

Scalp nerve block (SNB), involving infiltration of sensory nerves, has been shown to reduce intraoperative hemodynamic fluctuations, opioid use, and facilitate faster recovery [1], [2], [7], [8], [9]. To enhance SNB efficacy, various adjuvants have been evaluated for accelerating onset and prolonging analgesia [10], [11], [12]. Dexmedetomidine, a selective α2-agonist, has shown synergistic effects with local anesthetics in peripheral nerve blocks (PNB), prolonging analgesia by inhibiting sodium/potassium currents and HCN channels, thus enhancing neuronal hyperpolarisation [13], [14].

The efficacy and safety of dexmedetomidine as an SNB adjuvant remains underexplored [15]. Therefore, this meta-analysis aimed to evaluate the efficacy and safety of dexmedetomidine as an adjuvant in SNB, focusing on attenuating the hemodynamic responses to noxious stimuli, reduction of postoperative pain scores, and perioperative opioid consumption. We also assessed its impact on rescue analgesia dose, timing and any adverse events.