A Quasi-linear Viscoelastic Constitutive Equation for the Brain: Application to Hydrocephalus

Hydrocephalus is a condition which occurs when an excessive accumulation of cerebrospinal fluid in the brain causes enlargement of the ventricular cavities. Modern treatments of shunt implantation are effective, but have an unacceptably high rate of failure in most reported series. One of the common factors causing shunt failure is the misplacement of the proximal catheter's tip, which can be remedied if the healed configuration of the ventricular space can be predicted. In a recent study we have shown that this is accomplished by a mathematical model which requires as input the knowledge of the speed at which the ventricular walls move inwardly. In this paper we report on a theoretical method of calculating this speed and show that it will become of great practical usefulness as soon as more experimental results become available.