Imaging of thoracolumbar spine traumas

Spine trauma is an ominous event with a high morbidity, frequent mortality, and significant psychological, social, and financial consequences for patients, their relatives and society. On average three out of four spinal fractures involve the thoracolumbar spine and up to one-third are complicated by spinal cord injury. Spinal cord injuries (SCI) are a significant cause of disability in US and in all western countries. Knowledge of the main principles of biomechanics is essential in understanding the patho-morphology of spinal injuries, and the evolution of the various classification systems. Classification systems should be able to create a common language between specialists in order to improve patients' prognosis, guide treatment and compare treatment outcomes. Imaging has always been crucial in the evaluation of the injury type and accompanied the development of different classification systems. Thoracolumbar spine (TLS) trauma has a wide spectrum ranging from minor isolated fractures to highly unstable fracture-dislocations. Early classification systems were based on the analysis of the pattern of bony injuries on radiographs and CT. Traditionally, conventional radiographs are performed to confirm the clinical suspicion and to depict the level and type of bone injury. However, because of their inherent limitations, radiographs are often more helpful in proving the existence of a suspected bony spinal injury rather than excluding it. Multidetector computed tomography (MDCT) is superior in evaluating bone anatomy and, especially in polytrauma patients, it is the first line imaging modality. Morphological bone damage may be accurately shown and classified on CT. the most recent classifications also incorporate the integrity of soft tissues structures, which is considered equally relevant to spinal stability. Injuries to ligaments and discs can only be suspected on radiographs and conventional CT, although dual-energy CT is offering new insights on collagen mapping of damaged discs. Magnetic resonance imaging (MRI) may directly assess disc and ligamentous injuries, but also subtle osseous injuries, playing a complementary role in defining the whole spinal damage and an eventual instability. MRI is the only valid modality to assess the spinal cord (SC) and is indicated whenever a neurologic injury is suspected. Advanced MRI techniques, such as diffusion weighted imaging (DWI) and tractography, may provide further information regarding the integrity of the white matter which may improve outcome prognostication. Despite challenges in terms of costs, availability, accessibility and specificity, MRI and advanced MRI techniques are increasingly being used in spinal injuries. We present a review on TLS traumas discussing on the development of different classification system used in their evaluation, the role of imaging for their detection and the correlation to the patients' outcomes and treatment options.