Seat belts and trauma: Clinical clues for the surgeon

Abstract

Since their introduction over 30 years ago, seat belts have reduced the overall mortality associated with motor vehicle accidents by as much as 50%. The position and adjustment of the seat belt appear to play an important role in preventing injury. The lap portion of the belt should be kept low on the abdomen at the level of the anterior superior iliac spine because the pelvis is structurally able to withstand impacts that would seriously damage the soft portions of the abdomen. The diagonal belt should be positioned in such a manner that the clavicle and the chest wall absorb a portion of the force load. The use of seat belts has been associated with a constellation of abdominal injuries, which has been termed “the seat belt syndrome.” The “seat belt syndrome” is most commonly associated with using a lap belt, but it has also been reported in occupants using 3-point restraints. The seat belt syndrome itself is characterized by injuries in the plane of the lap portion of the belt, particularly with laceration of the colon, small bowel, and occasionally the stomach, the liver and spleen, occasional injury of the pancreas, major vascular injuries, and also lumbar spine or spinal cord injury, ie, “chance fractures.” Some serious injuries may be present without early symptoms or physical signs, and neither CT scanning nor DPL is fully reliable or accurate in finding the injury. Prompt diagnosis may be difficult and requires a high index of suspicion as well as a determined approach that may include exploratory celiotomy. The management of patients with potential intra-abdominal injuries resulting from blunt trauma continues to challenge surgeons. Much work continues to be done in the design of automobiles that will ultimately negate the injury that results from the transfer of kinetic energy to the human body. Preemptory strategies may involve crash avoidance techniques, evolutions in highway design, and more intensive driver education as the environment becomes more technologically advanced. Until the time that all automobile passive and active restraint systems are able to abolish all injury, it is up to the surgeon to maintain an appropriate level of suspicion in determining the risk of significant intra-abdominal trauma. Although much has been published in the engineering literature on this subject, recent large population-based reports in the medical literature are few. These 4 articles provide useful direction about the relative risks of injury and the most logical approach to diagnostic evaluation. For the most part, injuries of this nature are relatively rare. Even so, the nemesis of the practicing clinical surgeon is the “negative” CT evaluation of the abdomen with the subsequent significant devascularized shear injury that seems to be specifically associated with seat belt injury. Yet to be determined is the role of newer modalities for diagnosing intra-abdominal injury, including the use of ultrasound. Perhaps we can look forward to newer applications of diagnostic studies that will help us solve the conundrum of the seat belt-injured abdomen unequivocally. Until then, it seems that the mainstay of diagnosis will be a high index of suspicion and external signs, when present, of the “seat belt syndrome.”