Also known as seat-belt injury
Due to hyperflexion of spine around anterior fulcrum in combination with posterior vertical distraction force in high-speed RTA with lap belt
Spinal column splits transversely in PA direction, which may involve bone components, disk, ligaments
Variations include classic Chance fracture, fulcrum fracture and pure soft-tissue flexion-distraction injury
Low velocity injury causes classic Chance fracture, which extends horizontally into vertebral body with no further bone disruption
High velocity injury causes horizontal fracture with a secondary burst fracture
Radiograph:
Horizontal fracture of pedicles, which extends transversely through vertebral body
Posterior vertebral body height may be increased in relation to adjacent inferior vertebral body, which distinguishes it from burst fracture, in which the posterior vertebral body height is reduced
Small wedge compression fracture of anterosuperior vertebral body may also be seen
CT:
Bilateral facet dislocation
Bilateral pedicular fractures
MR:
Injuries of posterior osteoligamentous components are well seen, which the hallmark of Chance fractures
Damage to subcutaneous tissues (edema, hemorrhage)
Torn supraspinous, interspinous, flaval ligaments, ALL
Edema in paraspinal musculature
Spinal cord injuries (30% to 40%)
Disk injury
Damage to adjacent vertebrae
References:
Groves CJ et al. Chance-Type Flexion-Distraction Injuries in the Thoracolumbar Spine: MR Imaging Characteristics. Radiology 2005;236:601-608
