Flexion and Distraction Fractures The most common mechanism of flexion and distraction injury is hyperflexion over a seat belt during sudden deceleration in a motor vehicle collision The lumbar spine is most commonly injured as the result of this hyperflexion Among the spinal injuries that can occur are distractions, subluxations, facet dislocations, and ligamentous ruptures, as well as compression fractures and Chance fractures In simple distraction injuries, the traumatic force is typically a Salter–Harris type I fracture due to the relatively weak physeal cartilage of the maturing vertebral body These fractures often heal well with appropriate immobilization Chance fractures result from a combined flexion-distraction mechanism, resulting in a horizontal split through both the body and posterior elements of a vertebra, almost always a product of a seat belt injury (and, once again, often in combination with an abdominal injury) ( Fig 111.57 ) Chance fractures may be associated with neurologic injury, and the presence of associated injuries often requires hospitalization For isolated bony Chance fractures, immobilization with a brace for several months is necessary If there is any ligamentous involvement, definitive care requires orthopedic surgery