Pediatric Abdominal Injury Patterns Generated by Lap Belt Loading

BACKGROUND: Abdominal injuries can occur in children wearing adult seat belts during motor vehicle crashes. The particular anatomic structures injured may depend on the position of the seat belt, but this relationship has never been quantified in a controlled setting. METHODS: Thirty-four dynamic tests, designed to replicate crash loading, were performed on a validated porcine model of the 6-year-old human abdomen. The lap belt was positioned initially at either an "upper" or "lower" location on the abdomen. Detailed posttest necropsies identified all resulting injuries, which were then correlated to the initial position of the seat belt. The utility of using the presence or absence of an abdominal abrasion to predict internal abdominal injuries was also investigated. RESULTS: The injury frequency distributions from upper and lower abdominal belt loading were found to be significantly different (p < 0.01). Upper abdominal loading most commonly produced splenic lacerations and rib fractures, whereas lower abdominal loading resulted primarily in injuries to the large and small intestines. The presence of an abdominal abrasion was found to be a fairly specific (Sp = 0.86) but not very sensitive (Sn = 0.33) predictor of internal injuries of moderate severity. CONCLUSIONS: The relative frequency of each injury coupled with the presence or absence of an abdominal abrasion ("seat belt sign") should aid clinicians during their evaluations of children involved in motor vehicle crashes with possible occult abdominal trauma. In addition, the presence of a seat belt sign may have greater utility ruling in potentially occult abdominal injuries rather than excluding them.