Bulging of paraspinal line in traumatic thoracal spinal compression fracture

Case contributed by René Pfleger
Diagnosis certain

Presentation

MVC. Multitrauma protocol.

Patient Data

Age: 45 years
Gender: Male

The soft tissue shadow of the left paraspinal line bulges near the diaphragm. Following trauma this finding is consistent with localized hematoma i.e. an indirect sign of a vertebral fracture. 

No mediastinal widening, no evidence of pulmonary contusion, pneumo- or hematothorax, no further evidence of fracture or dislocation.

Conclusion

Lower thoracic vertebral fracture probable.

CT confirms fracture of T12 with slightly wedged anterior part, fracture line not extending to posterior cortex nor lamina. Subtle left paravertebral hematoma is also visualized. 

Incidental note is made of hepatomegaly, slightly wedged vertebra T11, general spondylotic changes, and notochordal rest level T12.

Conclusion

Traumatic thoracic spine compression fracture T12.

AP projection of thorax depicting bulging of soft tissue shadow of left paraspinal line (red arrow), better appreciated on slightly darkened view settings.

Illustration of deviation of left paraspinal line caused by compression fracture with associated hematoma.

Sagittal view of the lower thoracic and spine depicts fractured anterior part of vertebra T12 (orange arrow) and intact posterior part (middle column, blue arrow), i.e. flexion fracture pattern compression type.

Coronal view of the lower thoracic and lumbar spine at the level of lower thoracic bodies depicts hematoma producing left sided bulge (red arrow) and part of the fracture itself (yellow arrow). 

3D volume rendering in sagittal view with spot on thoracolumbar transition illustrates fracture line involving left-sided anterolateral part of vertebra T12 (black arrows), resulting in slight height loss. Fracture line exits well before middle column i.e. posterior part of vertebral body (white arrow).

Illustration of deviation of both paraspinal lines caused by compression fracture with associated hematoma

Case Discussion

Case key points

  • Vertebral compression fractures are a specific subtype of spinal flexion fractures. They are caused by axial compression forces, leading to fracture and height loss of the anterior part with the posterior part remaining intact. They are considered stable, in contradiction to most of the more severe burst fractures (the other subtype of hyperflexion spinal injury pattern).
  • Symptoms and signs of spinal fractures are often delayed and some patients may not demonstrate any neurological abnormality at all. 
  • While computed tomography CT is considered the gold standard in diagnosing and characterizing the fracture type, radiographs are often used for screening.
  • More or less subtle radiographic signs of vertebral compression fracture may be visualized on both the lateral and anteroposterior radiographs of the spine (deviation of paraspinal line in thoracic fractures, increased interpedicular distance in all fractures)
  • To distinguish between the simple wedge compression fracture and a burst fracture, the posterior vertebral body cortex or posterior vertebral cortex should be identified; the term "stable injury" should only be applied to minimal to moderate height loss (<50%) and overtly intact posterior cortex. Holding threshold for CT low may be prudent.
     
  • By far the majority of spinal compression fractures occur at the thoracolumbar junction.
  • While osteoporosis is the most common etiology of vertebral compression fractures, trauma, infection and neoplasm can also lead to these type of fractures.

Acknowledgements: special appreciation and thanks to Dr Matt Skalski for the terrific illustrations.

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