Clinical Research Directory

Inclusion Criteria: * Aged 18 years and older * Scheduled for elective intracranial surgery with skull pin head holder fixation * Classified as American Society of Anesthesiologists (ASA) physical status I-III * Provided written informed consent in the preoperative period Exclusion Criteria: * Allergy to local anesthetics * Coagulopathy or anticoagulant use * Local infection at injection site * Pregnancy or breastfeeding * Chronic opioid use (\>3 months) or chronic pain syndrome * Severe psychiatric disorders affecting pain assessment * Emergency surgery * Active infection or rheumatic disease * Hematological disease or malignancy (active or within 5 years) * Recent use of biological agents, chemotherapy, or corticosteroids (within 30 days) * NSAID use within 24 hours before surgery * Advanced organ failure (NYHA III-IV, Child-Pugh C, eGFR \<30 mL/min) * Refusal to participate * Communication difficulties preventing pain assessment