Postoperative Delirium Following Craniotomy: A Systematic Review and Meta-Analysis of Incidence, Risk Factors, and Clinical Outcomes

Abstract

Background & Objective: Postoperative delirium (POD) is a frequent neuropsychiatric complication linked to substantial morbidity and mortality after major surgery. Patients undergoing craniotomy may be vulnerable due to direct brain manipulation, perioperative neuroinflammation, and neurological injury; however, the incidence, risk factors, and clinical impact of POD in this population remain incompletely characterized. This review and meta-analysis aimed to evaluate the incidence, risk factors, and clinical outcomes of POD following craniotomy in adult patients. Methodology: A systematic review and meta-analysis (CRD420261444486) was conducted. Databases were searched for studies published 2020–2026 reporting POD incidence, risk factors, preventive interventions, or clinical outcomes after craniotomy. Observational studies, RCTs, and prediction model studies were included. Random-effects meta-analysis with restricted maximum likelihood estimation and logit transformation calculated pooled incidence. Risk of bias was assessed using ROBINS-I, RoB 2, and PROBAST as appropriate. Results: Eighteen studies (9,145 patients) were included; 16 (n = 8,822) were eligible for quantitative synthesis. Pooled incidence of POD following craniotomy was 23.2% (95% CI 19.9–26.9%), with substantial heterogeneity (I² = 90.4%; 95% prediction interval 12.1–42.2%). Subgroup analyses by postoperative setting, patient population, and assessment instrument did not identify significant sources of heterogeneity. Older age, frailty, lower cognitive reserve, malignant pathology, frontal lobe approaches, prolonged operative duration, benzodiazepine exposure, blood transfusion, metabolic derangements, and emergence delirium were the most consistent risk factors. POD was associated with prolonged hospitalization, increased ICU use, higher complications, increased costs, and greater in-hospital mortality. Two RCTs of dexmedetomidine showed reduced POD versus placebo, including one multicentre trial reporting a relative risk reduction of ~49%. Conclusion: POD following craniotomy is common, affecting nearly one in four patients, with a substantial clinical and healthcare burden. Risk arises from interacting preoperative vulnerability, tumour/surgical characteristics, and perioperative stressors. Evidence supports systematic perioperative delirium surveillance and targeted preventive strategies in high-risk patients, with further multicentre prospective studies needed. Key Words: Post Operative Delirium, Craniotomy.