History

1
History 23 y/o AD male who fell 30 feet while
intoxicated and attempting To climb into his
barracks window. The pt lost consciousness with
the fall and awoke in the hospital. He c/o LBP
at the level of L1 which did not radiate. He
denied pain elswhere, and had no radicular
symptoms. Physical Exam Lumbar spine TTP at
L1 Neurologically intact throughout
2
Anterior wedge fxr at L1 with 35 loss of
vertebral body height. Also, note slight
anterior compression of T12
3
Oblique fxr through L1 verterbral body with
slight lateral displace-ment of fragments. Note
transverse fxr of left pedicle at L1
4
Horizontal fracures extending through both
pedicles and lamina into the spinous processes of
L1. Bilateral transverse process fractures at
L1.
5
Sagital CT reconstruction (Arrow at L1)
6
Anterior wedge deformity of L1. Bone marrow
edema and a low signal intensity horizontal
linear signal in the mid-portion Note
compression of T12 and bone marrow edema of T12
and L2. Also, note soft tissue/ligamentous edema
from distraction of posterior elements at L1.
7
Bilateral transverse process fxrs. Soft tissue
edema surrounding spinous process at L1
8
Distraction of posterior elements at L1 fxr
cleft. Soft tissue edema adjacent to spinous
processes
9

• Chance Fracture
• Flexion-distraction injury of the lumbar spine
• Severe forward flexion of the spine across a
  restraining device during sudden deceleration.
• Spine above the restraining device is pushed
  forward and distracted from the lower, fixed
  portion of the spine.
• Often called a seat-belt fracture
• Often associated with wearing a lap belt only.
• Can happen in situations other than lap-belt
  automobile accidents.

10

• Chance fractures
• horizontal splitting of the L1 vertebra
• Begins in the spinous process or lamina and
  extends through the pedicles and vertebral body.
• Hallmark is a transverse fracture without
  dislocation or subluxation.
• No damage to ligamentous structures in true
  Chance fracture
• Chance variant fractures may have involve
  ligaments/discs
• Stable fractures
• Transverse processes may be horizontally
  fractured.
• Often associated with an compression fracture of
  the anterior vertebral body
• Associated with soft tissue injury
• Manifest by edema with increased signal intensity
  of MRI.

11
Chance fracturehorizontal splitting of vertebra
no ligament disruption
Fracture-dislocation Flexion-distraction type
12

• References
• Greenspan, A., Orthopedic Radiology A Practical
  Approach 3rd Edition. p. 371-379, 2000
• Ramsey, R.G., Teaching Atlas of spine Imaging. P.
  275, 1999