Mechanics of Retinal Hemmorhage in Abusive Head Trauma

Abusive head trauma is the leading cause of child abuse death for children under 2 years of age, and can be some of the most challenging cases for prosecutors, law enforcement professionals, and child protection advocates. Often, no one other than the accused is present to witness the event, and children, especially infants, are too young to communicate what events led to their injuries. Cases are further confounded by the lack of rigorous scientific data on the mechanisms of injuries associated with abusive head trauma. One of these injuries, retinal hemorrhages, are prevalent in 44-83% of abusive head trauma cases, but can also be present in 5-15% of accidental head trauma cases. Retinal hemorrhage severity can vary widely, and cases of mild to moderate retinal hemorrhage have been reported in both accidental and abusive head trauma. This can result in a substantial degree of uncertainty, and potential interpretive bias, in the courtroom. Rigorous, well-controlled studies investigating the mechanics of retinal hemorrhage could reduce much of this uncertainty.

The goal of this proposal is to quantify the forces required to cause mechanical damage to retinal microvasculature, and elucidate the effects of force severity and repetitive head trauma on retinal blood vessel mechanical integrity. To achieve this goal, molecular and microstructural damage will be quantified following two distinct loading mechanisms associated with abusive head trauma. The effect of the vascular arcades on vitreoretinal adhesion and microvasculature damage will be determined. This proposal will measure the forces required to initiate damage during vitreoretinal traction, and identify locations of damage with increasing force severity. Finally, proposed research will investigate the effect of repetitive vitreoretinal traction on the retinal microvasculature to quantify the accumulation of damage associated with repetitive head trauma. These data will be the first to establish force-structure-damage relationships in the retinal microvasculature, and will lay the necessary foundation for differentiating retinal hemorrhage patterns and severity between accidental and abusive head trauma. CA/NCF