Background: Hydrocephalus is a medical condition consisting of an abnormal\naccumulation of cerebrospinal fluid within the brain. A catheter is inserted in one of\nthe brain ventricles and then connected to an external valve to drain the excess of\ncerebrospinal fluid. The main drawback of this technique is that, over time, the ventricular\ncatheter ends up getting blocked by the cells and macromolecules present in\nthe cerebrospinal fluid. A crucial factor influencing this obstruction is a non-uniform\nflow pattern through the catheter, since it facilitates adhesion of suspended particles to\nthe walls. In this paper we focus on the effects that tilted holes as well as conical holes\nhave on the flow distribution and shear stress.\nMethods: We have carried out 3D computational simulations to study the effect of the\nhole geometry on the cerebrospinal fluid flow through ventricular catheters. All the simulations\nwere done with the OpenFOAM�® toolbox. In particular, three different groups of\nmodels were investigated by varying (i) the tilt angles of the holes, (ii) the inner and outer\ndiameters of the holes, and (iii) the distances between the so-called hole segments.\nResults: The replacement of cylindrical holes by conical holes was found to have a\nstrong influence on the flow distribution and to lower slightly the shear stress. Tilted\nholes did not involve flow distribution changes when the hole segments are sufficiently\nseparated, but the mean shear stress was certainly reduced.\nConclusions: The authors present new results about the behavior of the fluid flow\nthrough ventricular catheters. These results complete earlier work on this topic by adding\nthe influence of the hole geometry. The overall objective pursued by this research is to\nprovide guidelines to improve existing commercially available ventricular catheters.
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