Strain analysis on the superficial surface of skull as intracranial pressure changing

The average intracranial pressure (ICP) of parietal position for adults is normally about 3.62 kPa. The brain appears to be mild injury as the ICP variation is about 2.5 kPa, moderate injury as the ICP variation is about 3.5 kPa, and severe injury as the ICP variation is about or more than 5 kPa. This paper analyzed the stress and strain on the exterior surface of human skull and the composite structure composed by skull and duramater with the finite-element software MSC-PATRAN/NASTRAN. The experiments were carried out on the strains of porcine skull slices, porcine and human coronal skulls to simulate the actual situation in the human craniocerebra. The results show that the strains of mild injury, moderate injury and severe injury are 1.5×10^-6, 2.5×10^-6 and 4.0×10^-6 respectively. It indicates that the strains on the exterior surface of skull are measurable and all within the range of instrument test. The minitraumatic method to measure ICP is feasible by pasting strain foils on the exterior surface of skull, by which ICP variation can be obtained through the corresponding operation to the strain of skull. Compared with the clinical methods of punching in the skull or puncturing in the spine cord, the strain-electrometric method is safe, simple, minitraumatic, accurate and feasible.