IS Case 231: Chance fracture - L3
Imaging Sciences URMC 2008
Publication Date: 2009-05-22
History
Patient is a 19-year-old male status post motor vehicle accident.
Findings
Plain film and CT images demonstrate a transverse fracture extending from the L3 vertebral body through the right-sided posterior elements, into the right transverse process. There is anterior wedge deformity of the L3 vertebral body. There is no dislocation or subluxation of the vertebral bodies.
Diagnosis
Chance fracture - L3
Discussion
This type of fracture was originally described by George Quentin Chance, a British radiologist, in 1948. It is a distraction injury most often seen in the area of the thoracolumbar junction and is often referred to as a “seatbelt fracture,” due to the frequency with which it is seen in MVA victims wearing only lap seatbelts (although this is exceedingly rare nowadays). The mechanism is an acute forward flexion of the spine during a sudden deceleration, which causes the spine above the belt to be pushed forward and distracted from the lower fixed part of the spine. Classically, there is a horizontal splitting of the vertebra, beginning at the spinous process or lamina and extending through the pedicles and the vertebral body without damage to the ligamentous structures. The constant feature is a transverse fracture without dislocation or subluxation of the vertebrae. The transverse process may be fractured as well and there is sometimes anterior compression of the vertebral body.
The fracture is often stable, because the upper half of the neural arch remains attached to the vertebra above and the lower half to the vertebra below. Associated abdominal injuries are common.
References
- # Greenspan A. Orthopedic Imaging: A Practical Approach. 4th ed., Lippincott Williams & Williams, Philadelphia. 2004: 388, 392-393.
- Goodrich JA. Chance fracture. e-Medicine, Jun 10, 2008. http://emedicine.medscape.com/article/1263663-overview.
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