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Back to Basics: An Imaging Approach to Thoracolumbar Trauma. 2008

General Spine

Anna Kiselyuk, MD,
Steven Lev, MD, ASSR Member

Scientific Poster

Exhibit Panels: 3

Purpose

To review the broad range of traumatic injury to the thoracolumbar spine, emphasizing the role of anatomical and biomechanical considerations. We discuss the applications of models of stability and fracture patterns, as well as the relative advantages of CT vs. MR. Other important topics we address are the indirect signs of thoracolumbar spine injury, delayed vertebral collapse and goals of treatment. Identification of both normal variants and fracture mimics is also emphasized.

Methods & Materials

We retrospectively reviewed the imaging studies (radiographs, multi-detector CT, MR) of patients presenting through our ED at our Level 1 trauma center and found to have acute thoracolumbar injury. We classified the injuries according to location, fracture pattern, ligamentous and paraspinal involvement. When available, we reviewed follow-up imaging to assess treatment success or failure. We include examples of entities that may be confused with acute traumatic injury and highlight the key differentiating features.

Results

The thoracolumbar junction is a transitional zone that is subject to increased biomechanical stress during acute trauma. The upper thoracic spine, stabilized by the ribcage, is less susceptible to injury. The forces commonly associated with bony/ ligamentous injury are axial compression, flexion, flexion-distraction or flexion-rotation, shear, lateral compression, and extension. Several schemes for assessing spinal stability have been proposed, dividing the spine into distinct columns. In the Denis model for example, the fracture is considered unstable when 2 out of 3 columns are disrupted. Examples of cases that we discuss include a burst fracture with acute spinal canal compromise, a chance fracture with associated sternal injury and a wedge compression fracture with subsequent worsening kyphosis. Chest radiography can demonstrate indirect signs of injury such as mediastinal widening and hemothorax. CT imaging allows for speedy coronal and sagittal reconstructions that can assist in prompt assessment of spinal alignment and stability. MRI is performed for improved evaluation of non-osseous involvement such as spinal cord contusions, ligamentous ruptures and epidural hematomas. Included is an unusual case of disk herniation secondary to a thoracic fracture, with associated cord compression. The goals of treatment are stabilization, preclusion of further neurological damage, and prevention of progressive deformity. We illustrate a case of progressive spine kyphosis despite surgical fixation. Commonly encountered normal variants such as limbus vertebrae and physiologic wedging are not to be mistaken for acute injury.

Conclusion

Thoracolumbar spine injury is complex and dependent on a variety of factors. A radiological approach incorporating an appreciation of spinal column anatomy, mechanism and type of injury as well as an assessment of stability, is critical in appropriate patient triage.

References

Ross JS, et al. Diagnostic Imaging: Spine. 1st edition. Amirsys, 2005.

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