Numerical Modeling of Venous Outflow from the Cranial Cavity in the Supine Body Position

Abstract

The hemodynamic relevance of differently located stenoses of the internal jugular veins remains undetermined. It particularly concerns nozzle-like strictures in the upper parts of these veins and stenotic jugular valves located at the end of these veins. This study was aimed at understanding flow disturbances caused by such stenoses. The computational fluid dynamics software Flowsquare+ was used. We constructed 3-dimensional models of the venous outflow, comprising two alternative routes: the tube representing the internal jugular vein and an irregular network representing the vertebral veins. At the beginning of the tube representing the internal jugular vein, differently shaped and sized short strictures representing nozzle-like strictures were built in. At the end of this tube, differently shaped membranes representing the jugular valve were built in. With the use of computational fluid dynamics modeling, we studied how these two obstacles influenced the outflow. We found that the most relevant outflow disturbances were evoked by the nozzle-like strictures in the upper part of the internal jugular vein that were small, long, or asymmetrically positioned. Very tight stenotic valves and septum-like malformed valve were equally hemodynamically relevant. These findings suggest that both upper and lower strictures of the internal jugular vein can be of clinical significance.