The Volume of the Third Ventricle as a Prognostic Marker for Shunt Dependency After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND: Hydrocephalus is a common sequelae of aneurysmal subarachnoid hemorrhage (aSAH). However, in daily routine it is difficult to predict a patient's need for ventricular shunt placement in the course of the disease. OBJECTIVE: The purpose of this study was to identify radiologic predictors for development of a shunt-dependent hydrocephalus after aSAH. METHODS: A cohort of 217 patients with aSAH with adequate pretreatment computed tomography (CT) imaging was retrospectively reviewed. All variables, including demographic data, treatment, and initial CT imaging were gathered and grading was performed using Hunt and Hess, Graeb, LeRoux, and modified Fisher scores. Analysis of the radiographic parameters consisted of straight measurement and three-dimensional volumetry using manual segmentation. Univariate and multivariate statistical analyses were performed to identify predictive parameters. RESULTS: Of 217 patients, 36 (17.5%) required a ventricular shunt (VS). A receiver operating characteristic analysis between the volume of the third ventricle and shunt-dependent hydrocephalus showed a significant cutoff at a volume of 2.3 cm(3) with a 4.3-fold higher risk for shunt dependency (P < 0.001). However, the treatment modality and classification according to the mentioned scores were not associated with the need for VS after aSAH. In univariate and multivariate analysis, the volume of the third ventricle on admission remained a significant prognostic marker for the need of a VS. CONCLUSIONS: Our data suggest that the volume of the third ventricle in the initial CT is a strong predictor for shunt dependency after aSAH.