Structural and mechanical characterization of thet superior sagittal sinus - bridging vein complex.

Acute subdural hematoma (ASDH) is one of the most frequent lesions inside the head observed in victims of bicycle related accidents. In nearly one third of the ASDH cases, the etiopathology directly relates to the rupture of a bridging vein (BV) which drains blood from the cerebral cortex into the superior sagittal sinus (SSS). To study the biomechanics of ASDH and other traumatic brain injuries and to assess the efficacy and improve the design of protective devices such as bicycle helmets, finite element (FE) head models are used. However, the accuracy of a FE head model depends, among other things, on the use of correct material properties for each cranial tissue which are , experimentally derived. In large contrast to other cranial tissues, e.g. the brain, the BVs is still a rather unknown complex within the head; yet it has a crucial role in the etiology of ASDH. Hence, this interdisciplinary research project conducts a thorough performance analysis of the state of the art finite element head model and its bridging vein representation. This is followed by the design and manufacturing of a novel two rail shear testing device for small soft tissue samples. Combining the experimental results with uni-axial tensile test data a fitting method is developed for a non-linear anisotropic material model. This novel material characterization approach is then applied to BVs in a pilot study.