Persistent Post-craniotomy Headache Following Adult Craniotomy: A Propensity Score-Matched Analysis of Scalp Block and Surgical Risk Factors.

OBJECTIVE: Persistent post-craniotomy headache (PCH) is a recognized complication affecting functional recovery. While scalp nerve blocks improve acute postoperative analgesia, their association with persistent headache remains uncertain. This study evaluated persistent PCH incidence and its association with scalp blocks after adult craniotomy. METHODS: This retrospective study included adults undergoing craniotomy at University Malaya Medical Centre between June 2018 and June 2022. PCH was defined using International Classification of Headache Disorders criteria. To reduce selection bias, an Inverse Probability of Treatment Weighting (IPTW) approach targeting the Average Treatment Effect on the Treated (ATT) was utilized. Variables were analysed using a covariate-adjusted ATT-weighted multivariable generalized estimating equation (GEE) model, and headache impact was evaluated with the Headache Impact Test-6 (HIT-6™). RESULTS: Among 171 patients, scalp block administration was independently associated with reduced odds of persistent PCH in the fully adjusted model (Adjusted OR = 0.243; 95% CI 0.064-0.923; p = 0.038). Surgical duration exceeding three hours increased persistent headache odds (Adjusted OR = 3.104; 95% CI 1.034-9.315; p = 0.043), while the absence of preceding headache was protective (Adjusted OR = 0.132; 95% CI 0.031-0.551; p = 0.006). On the HIT-6™, 44% of assessed patients reported functional impairment, and 29% reported substantial to very severe impact. CONCLUSION: Persistent PCH affected nearly one-third of the cohort. Scalp block and the absence of preceding headache independently reduced persistent headache odds, whereas prolonged surgical duration increased them. Prospective studies with standardized perioperative data are required to clarify if scalp blocks reduce persistent post-craniotomy headache risk.