Jan Hemza

Pseudotumor Cerebri: A New Concept of Pathophysiology

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-Hooks 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.

Skull Base Surgery and Venous problems

The cerebral venous system is as important as its arterial system. The authors have been studying cerebral venous problem for a long time. In the prezent study, the authors have researched venous complications and problem correlated to biomechanical and hemodynamical studies. The histobiomechanical characteristics of bridging veins and cerebral sinuses were studies with the tests system MTS 858.2 Mini Bionix (unique testing system in Europe). The bridging veins have a very low stronghold on longitudinal traction. Sinuses, on the other hand, are very rigid. This might influence blood outflow from the brain in normal physiology and any pathological situation, including head trauma. The authors developed a special program for modeling the cardiovascular system and the cerebral venous system. In this study, they illustrate the problem of bridging veins and the venous sinuses. From biomechanical and physiological view-point, they propose a venous classification of the cardiovascular system has the potential to change after application of treatment. The authors report on clinical problem and aspects (destruction of bridging veins during trauma, carotid-cavernous fistulas, and venous neurological deficits).

Is the Cribriform Plate an Effective Border

This work describe the problems with surgical procedure trough cribriform plate of ethmoid bone to frontal cerebral lobe.