Investigation of the Effects of Preoperative Ultrasound-Guided Scalp Block on Perioperative Opioid Consumption, Hemodynamic Stability, and Inflammatory Response in Patients Undergoing Craniotomy With a Skull Pin Head Holder

Craniotomy is a surgical procedure performed to access brain tissue or vascular structures through temporary removal of a portion of the skull (1). The primary goal of neuroanesthesia is to preserve cerebral autoregulation, prevent increases in intracranial pressure, and maintain adequate cerebral perfusion pressure by controlling autonomic nervous system activation induced by surgical stress and nociceptive stimuli (2).

The pin head holder (Mayfield type), which is used to stabilize the surgical field during intracranial procedures, generates intense nociceptive stimulation due to the dense sensory innervation of the scalp. This stimulation may lead to sudden increases in blood pressure and heart rate, thereby raising intracranial pressure (3). Although deep levels of anesthesia and high-dose opioids are commonly used to control this hemodynamic response, such approaches may result in undesirable perioperative outcomes, including respiratory depression, postoperative nausea and vomiting, and prolonged recovery time associated with increased opioid consumption (4,5).

Scalp block is an effective regional anesthesia technique frequently used in intracranial surgery and is based on blocking the sensory nerves of the scalp using local anesthetic agents (3). This technique targets the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater occipital, and lesser occipital nerves, thereby reducing the transmission of painful stimuli to the central nervous system (6). Scalp block was first described by Pinosky et al. in 1996, and it has been demonstrated that bupivacaine-based scalp block reduces increases in blood pressure and heart rate associated with pin head holder placement and decreases intraoperative anesthetic requirements (3,6).

The use of ultrasonography (USG) in scalp block enhances block accuracy through real-time visualization of superficial nerves and vascular structures, ensures appropriate distribution of local anesthetics within fascial planes, and reduces the risk of complications such as intravascular injection and local anesthetic systemic toxicity (7).

In addition to hemodynamic alterations, surgical trauma and pain also trigger a systemic inflammatory response. During this process, changes in neutrophil, lymphocyte, and platelet counts are reflected in peripheral blood parameters. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory response index (SIRI), and systemic immune-inflammation index (SII) are used as indicators of surgical stress and inflammation (8,9).