Introduction: Subdural hematoma (SDH) evacuation is a common neurosurgical procedure with high risk for morbidity and mortality (1). The purpose of this study was to develop a risk score for 30-day mortality following SDH evacuation on the basis of readily available pre-operative information.

Methods: Data recorded in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database between 2006 and 2014 were selected on the basis of ICD-9 (International Classification of Diseases, Ninth ed.) and CPT (Current Procedural Terminology) coding (2) (Fig. 1A). Sequential univariate and multivariate analyses were used to identify significant independent predictors of 30-day mortality among 32 pre- operative factors. Multivariate regression coefficients were used to develop a weighted risk score capable of separating outcome groups with high sensitivity and specificity.

Results: Following list-wise exclusion of patients with incomplete datasets, 1271 patients (35.6% F; median age 73.0 years, IQR 44.1-89.0 years) were examined. Sequential univariate and multivariate analysis identified seven independent predictors of 30-day mortality (OR = adjusted odds ratio) (Fig. 1B): emergency case (OR 2.27), age >= 65 years (OR 2.42), ventilator dependent status (OR 4.95), dialysis (OR 5.16), bleeding disorder (OR 2.37), WBC count >= 10,000 µL-1 (OR 1.79), and platelets < 150,000 µL-1 (OR 2.18). Receiver operating characteristic (ROC) analysis demonstrated impressive outcome discrimination (area under the curve = 0.82, CI 5-95% = 0.78 – 0.86) (Fig. 1C). Optimal score threshold was used to identify high-risk (mortality 35.0%) and low-risk (mortality 6.33%) patient groups (Fig. 1D).

Conclusions: We demonstrate a novel risk score capable of classifying patients based on 30-day postsurgical mortality. Application will provide an improved means of predicting outcomes for patients undergoing craniotomy or craniectomy for SDH evacuation.

Patient Care: The absence of a rigorous and transparent evidence-based scoring system for the risk of mortality associated with evacuation of subdural hematoma precludes informed management of patients and expectations post-surgically. In this study, we introduce a scoring system that may assist in presurgical decision-making and mortality risk stratification.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Recognize the need for improved pre-operative risk stratification in cases of subdural hematoma evacuation; 2) Identify independent risk factors that predict 30-day mortality from subdural hematoma evacuation; and 3) Discuss the clinical utility of the novel risk score system proposed by the authors.

References: (1) Ryan CG, Thompson RE, Temkn NR, et al. J Trauma Acute Care Surg 2012; 73(5): 1348–1354. (2) Lukasiewicz AM, Grant RA, Basques BA, et al. J Neurosurg 2016; 124(3):760-766.