Trauma X-ray - Axial skeleton
Thoracolumbar spine - Abnormal

Key points

  • Use a systematic approach
  • Correlate radiological findings with the clinical features
  • If 'instability' is suspected then further imaging with CT should be considered
  • If you see one fracture - check for another

Thoracolumbar spine - Systematic approach

  • Coverage - Adequate?
  • Alignment - Anterior/Posterior/Lateral
  • Bones - Cortical outline/Vertebral body height
  • Spacing - Discs/Spinous processes/Pedicles
  • Soft tissues - Paravertebral
  • Edge of image

Basic thoracolumbar spine injury classification

  • 1 column - Anterior compression (or isolated spinous process injuries)
  • 2 column - Burst injuries
  • 3 column - Flexion-distraction 'Chance-type' injuries

A good understanding of normal appearances and a systematic approach are required for assessment of the T-spine and the L-spine (see previous page).

Injury classification

The 'three column model' (see previous page) can be used to form a basic classification of thoracolumbar spinal injuries (see box). This page also discusses osteoporotic fractures, and fractures of the transverse and spinous processes.

Spinal injuries which are seen to disrupt structures of 2 or more columns are considered 'unstable'. If the middle column is seen to be injured it is usually taken that another column must be injured even if no anterior or posterior column fracture is visible.

If an injury is seen which disrupts 1 column then a second fracture is also present in approximately 15% of cases. If a 2 column injury is seen then likelihood of a second fracture increases to 40%.

RULE: If you see one fracture - check for another

1 Column - Anterior compression injury

Anterior compression injury is a common fracture pattern which results from traumatic hyper-flexion with compression. Although considered 'stable' the greater the loss of height anteriorly the greater the risk of middle column involvement. X-ray may underestimate the extent of injury and so if there has been high risk injury or other suspicion of instability then CT should be considered.

Anterior compression injury - L-spine - Lateral

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Anterior compression injury - L-spine - Lateral

  • (Same patient as image below)
  • A poorly defined dense (white) fracture line is visible with a detached fracture fragment (asterisk)
  • L1 has lost height anteriorly and there is disruption of the anterior column only

Anterior compression injury - L-spine - AP

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Anterior compression injury - L-spine - AP

  • (Same patient as image above)
  • Loss of vertebral body height can be seen but the fracture is not visible on this view

2 column - 'Burst' fracture

'Burst' fractures result from high force vertical compression trauma. Posterior displacement of vertebral body fracture fragments into the spinal canal leads to a high risk of spinal cord or nerve root damage.

Thoracolumbar 'Burst' fracture - Lateral

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Thoracolumbar 'Burst' fracture - Lateral

  • (Same patient as image below)
  • Both the anterior and middle columns are disrupted
  • Injury has resulted in increased kyphosis
  • A large vertebral body fragment is displaced anteriorly

Thoracolumbar 'Burst' fracture - AP

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Thoracolumbar 'Burst' fracture - AP

  • (Same patient as image above)
  • The T12 vertebral body has lost height and the adjacent rib is fractured
  • The interpedicular width should increase gradually from superior to inferior (white dotted lines)
  • At the level of the fracture there is sudden widening of the interpedicular width - Note: This sign is not always visible in burst fractures
  • The normal paravertebral soft tissues (asterisks) is widened by a paraspinal haematoma at the level of the fracture

3 column - Flexion-distraction fracture

Flexion-distraction injuries are associated with high force deceleration injuries and are most common at the thoracolumbar junction. Also known as 'Chance-type' fractures (after the radiologist who first described them) these injuries are unstable and carry a high risk of neurological deficit and abdominal organ injury.

The 'fracture' line may pass through the disc rather than the vertebral body, and so there may not be visible bone injury of the anterior column.

Flexion-distraction / 'Chance' fracture - Lateral

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Flexion-distraction / 'Chance' fracture - Lateral

  • All three columns are disrupted
  • A = Widened spinous processes (SP) indicating disruption of the interspinous ligaments at the level of the fracture
  • B = Normal interspinous distance

Flexion-distraction / 'Chance' fracture - AP

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Flexion-distraction / 'Chance' fracture - AP

  • The interspinous distance is increased at the level of the fracture
  • In this case the pedicles and transverse processes have been split horizontally

Osteoporotic 'insufficiency' injuries

Thoracolumbar spine injuries are very common in patients with osteoporosis. Common fracture patterns include 'wedge' injuries and 'biconcave' fractures.

Thoracic spine - 'Wedge' compression fracture

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Thoracic spine - 'Wedge' compression fracture

  • Note the low density (blackness) of the vertebral bodies
  • The vertebral body has lost height anteriorly
  • Kyphosis is increased

Lumbar spine - Biconcave fracture

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Lumbar spine - Biconcave fracture

  • Note the low density (blackness) of the vertebral bodies
  • Compression injuries of both the superior and inferior endplates of the vertebral body have resulted in a biconcave appearance
  • The vertebral body has also lost height anteriorly - compare to level below (superimposed dotted line)

Other fractures

Spinal fractures may be isolated to the spinous or transverse processes.

Transverse process fractures are often not visible with X-ray - (only seen on CT), and are often associated with other fractures - so if seen are a prompt to recheck all X-ray images available and consider further imaging. Transverse process fractures are also associated with injury to the kidneys.

Transverse process fracture - Lumbar spine AP

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Transverse process fracture - Lumbar spine AP

  • Multiple fractures of the transverse processes are seen on one side

Spinous process fracture - Lumbar spine - Lateral

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Spinous process fracture - Lumbar spine - Lateral

  • Only 1 column is visibly injured but further imaging should be considered

Page author: Salisbury NHS Foundation Trust UK (Read bio)

Last reviewed: March 2016