Lumbar chance fracture in an adult snowboarder: unusual mechanism of a chance fracture.

STUDY DESIGN: A case of a Chance fracture in an adult snowboarder following a fall is presented. The mechanism of this fracture is reported.

OBJECTIVE: To increase awareness of the spinal injuries in snowboarders and to propose the mechanism of this unusual fracture.

SUMMARY OF BACKGROUND DATA: Chance fractures rarely occur in adults and are very unusual in children. Nearly all of the reported cases are in conjunction with lap-type seat belt injuries. To the authors' knowledge, this is the first reported case of a lumbar Chance fracture in an adult snowboarder.

METHODS: A 25-year-old snowboarder sustained an L1 Chance fracture following a fall backward. The patient was placed in a hyperextension cast, and the cast was changed to a thoracolumbar orthosis after 12 weeks.

RESULTS: Complete bony union was obtained with body cast immobilization, and an excellent functional restoration was obtained.

CONCLUSIONS: Chance fractures are horizontal splitting fractures of the posterior elements of the vertebrae, and the mechanism of the injury is that of a hyperflexion of the spine over a fulcrum. A Chance-type fracture can be seen in an adult snowboarder, when acute hyperflexion of the spine occurs following a fall backward.