Pseudotumor Cerebri: A New Concept of Pathophysiology

Abstract

The diagnosis of pseudotumor cerebri has many hypotheses about its pathophysiological pathways. A review of the literature about this diagnosis has led to a revision of pathophysiological pathways regarding the pseudotumor cerebri as nonthrombotic theory. The author studied the physiological phenomena of bridging veins and brain outflow. Biomechanical material properties of the bridging brain veins were investigated experimentally and theoretically. The main goal of developed theory is to formulate the biomechanical conditions (geometrical dimensions, viscoelastic properties of veins, and blood fluid flow conditions) at which an unstable behavior or even the vein collapse can occur. The Neo-Hook's material model was used to determine the analytical formula for the collapse conditions. It was proved that for the brain-vein contraction (approximately 5%), the vein collapse can occur even under normal physiological conditions into vessels-the angiosynizesis. The weak formulation is based on the virtual work principle. To describe the wider class of problems, three material models were simulated: the Neo-Hook, the isotropic Gent, and the anisotropic Gent to include the influence of collagen structure of blood vessels. Simultaneous clinical observations (histological findings), in vitro experiments, and numerical modeling give sufficient data to predict biomechanical conditions of the angiosynizesis. The fluid structure interaction is studied experimentally on the special experimental line. The biomechanical, histological study and biomechanical and the mathematical modeling of the function of bridging veins and venous sinuses allowed development of new pathways for this diagnosis.