Finite element analysis of brain contusion: an indirect impact study

The mechanism of brain contusion has been investigated using a series of th ree-dimensional (3D) finite element analyses. A head injury model was used to simulate forward and backward rotation around the upper cervical vertebr a. Intracranial pressure and shear stress responses were calculated and com pared. The results obtained with this model support the predictions of cavi tation theory that a pressure gradient develops in the brain during indirec t impact. Contrecoup pressure-time histories in the parasagittal plane demo nstrated that an indirect impact induced a smaller intracranial pressure (- 53.7 kPa for backward rotation, and -65.5 kPa for forward rotation) than th at caused by a direct impact. In addition, negative pressures induced by in direct impact to the head were not high enough to form cavitation bubbles, which can damage the brain tissue. Simulations predicted that a decrease in skull deformation had a large effect in reducing the intracranial pressure . However, the areas of high shear stress concentration were consistent wit h those of clinical observations. The findings of this study suggest that s hear strain theory appears to better account for the clinical findings in h ead injury when the head is subjected to an indirect impact.