Feasibility Study of SIMon in Predicting Head Injuries in Children

The objective of this study was to assess the feasibility of SIMon (Simulated Injury Monitor) software package in predicting head injuries to children in automotive crashes. The human finite element head model (FEHM) within the SIMon was used for this study. Reconstruction of ten real world crashes involving children ages 4-8 years were conducted for this study. The selected cases were divided into five categories based on the type of head injury sustained by the child occupant. The categories were concussion only, skull fracture only, intracranial only, intracranial with skull fracture, and no injury. Two cases in each category were selected for reconstruction. Input for SIMon, was obtained from the reconstruction of real world crashes using EDSMAC4 (HVE environment) and MADYMO. EDSMAC4 in HVE environment was used to obtain the vehicle motion while MADYMO solver was used to obtain the occupant kinematics data in the crash. Finally, to reconstruct the loading on the skull and brain tissue in the crash, SIMon FEHM was used in the study. Three injury metrics were calculated: Cumulative strain damage measure (CSDM) - a correlate for diffuse axonal injury (DAI); Dilatational damage measure (DDM) - to estimate the potential of contusion; and Relative motion damage measure (RMDM) - to correlate for acute subdural hematoma (ASDH). Maximum values of the above injury metrics were plotted on the injury probability curve to assess the probability predicted by the SIMon FEHM.

Based on this study, only 1 of the 10 cases with associated head injuries was correctly predicted by SIMon FEHM. The results showed correct trend of the probability of injury occurrence for the intracranial alone injury group; with low probability values. While with no injury cases, the SIMon FEHM showed the probability of occurrence of concussion type injuries. SIMon also failed to correctly predict cases under the concussion only injury group. The SIMon FEHM in combination with the injury tolerance curves, in their present form, could not be used to predict the various head injuries in the children.