Category 6, Item 26
The x-rays demonstrate a transverse fracture through the body of the third lumbar vertebra, called a Chance fracture. This injury is the result of a distraction force applied in flexion that splits the spinous process in the transverse plane and proceeds ventrally through the vertebral body or the intervertebral disk. Chance fractures are seen frequently in drivers restrained by improperly applied lap belts and subjected to sudden deceleration forces.
Small bowel injury is an associated finding in more than 50% of cases, resulting from direct compression of the fluid-gas filled bowel between the restraint belt and the spinal column. The early diagnosis of hollow viscus injuries is difficult at best, because symptoms and physical findings on abdominal examination may be lacking.
The association between Chance fractures and hollow viscus injury is so strong that many authors recommend celiotomy unless abdominal examination is completely benign in an alert patient or diagnostic peritoneal lavage is normal in those who cannot be examined reliably. Abdominal sonograms and computed tomography are not consistently helpful; findings are often quite subtle.