Hepatic Rupture Resulting from Seat-belt Trauma During Car Crash

The Machanism of Breaking Stress on the Liver

Abstract

Breaking stresses were measured to investigate blunt trauma to the hepatic tissues by a 3-point seat-belt during car crash. The minimum deceleration and velocity were determined from the breaking stresses on the liver and from the internal force on the contact area against the liver and thoracoabdominal wall (the body wall). The body cushioning effect was estimated from the breaking stresses and the impact transmitted to the body wall from the seat-belt. The breaking stresses were determined in the livers of 5 swine with and without its visceral peritoneum by means of a rheometer. The contact wall area covering the liver was measured by cross-sectional CT scans and was positioned from its left end at mid-line to a point of 45 degrees to the left. The contact area with the seat-belt and the body wall also was measured to calculate the impact force from the seat-belt on an occupant seated on the left front seat. The breaking stresses on the liver were 4.7±0.3kgf/cm² with the peritoneum, and 3.5±0.2kgf/cm² without the peritoneum. In conclusion, the minimum deceleration and velocity for the 45-degree area were 59±11g and 84-100km/h. Furthermore, the body cushioning effect was estimated at 25-32kgf/cm².