Chance fracture

Chance fractures are pure bony flexion-distraction type injuries thatof the spine that extend all the way through the spinal column: from posterior to anterior through the spinous process, pedicles, and vertebral body, respectively columns. 

Pathology

Mechanism

They tend to occur from a flexion-distraction injury of the vertebral body and distraction type injury of the posterior element ¹. The most common history is that of a back seat passenger restrained by a lap seatbelt and involved in a motor vehicle accident or that of a person who has fallen from a height. The anterior column fails in compression whereas the middle and posterior columns fail in distraction.

Location

This fracture most commonly occurs about the upper lumbar spine (with the thoracolumbar junction accounting for ~50% of cases ³), but it may be observed in the midlumbar region in children.

Associated injuries

There is a high incidence of associated intra-abdominal injuries (especially the  pancreas and duodenum) that can result in increased morbidity and mortality. Associated intra-abdominal injuries appear to be more common in the pediatricpaediatric age group with incidence approaching 50%.

If unrecognized, Chance injuries may result in progressive kyphosis with resulting pain and deformity.

Radiographic features

Plain radiograph

• empty vertebral bodysign: can be seen on an AP radiograph and results from the vertical separation of the posterior elements displacing the spinous processes or spinous process fracture fragments off the vertebral body on the AP projection
• horizontal fracture through one or both pediclestransverse fractures across the transverse processes, laminae, and articular processes
• widening of the interpedicular distance: often suggests a burst component
• transverse fractures across the transverse processes, laminae, and articular processes
• widening of the facet joints and increased intercostal spacing
• widening of the interspinous spacing

CT

More accurately delineates fracture details.

Treatment and prognosis

The fractures generally can be reduced by placing the patient on a Risser table with hyperextension applied to the thoracolumbar junction prior to applying a fiberglass or plaster cast.

If immobilization is impractical (large body habitus) or the patient has polytrauma, surgical management may be indicated. 

History and etymology

It is named after George Quentin Chance, British radiologist who first described it in 1948 ².