The Relationship between the Progression of Kyphosis in Stable Thoracolumbar Fractures and Magnetic Resonance Imaging Findings

STUDY DESIGN Retrospective study. PURPOSE To investigate the relation between the progression of kyphotic deformity and magnetic resonance imaging (MRI) findings in conservatively treated stable thoracolumbar fractures. OVERVIEW OF LITERATURE When treated conservatively, excessive progression of kyphotic deformity and vertebral compression can emerge during follow-up. We sought to identify predictors of vertebral body deformation using MR images. METHODS The presence in MR images of anterior longitudinal ligament (AL) or posterior longitudinal ligament (PL) injury, superior or inferior endplate disruption, superior or inferior disc injury in fractured vertebral bodies, the existence of low signal intensity on T2 weighted images, and bone edema of intravertebral bodies were assessed. RESULTS The presence of superior endplate disruption and a higher level of bone edema were found to cause the progressions of kyphotic angle (KA), wedge angle (WA), and anterior vertebral compression (AVC) rate. When AL or superior disc injury was observed, only KA increased meaningfully. When low signal intensity was present on T2 weighted images WA and AVC increased significantly, but PL injury, inferior endplate disruption, and inferior disc injury showed no notable correlation with kyphotic deformity progression. The risk factors found to be associated with an increase of KA to >5° were AL injury, superior endplate disruption, superior disc injury, and a bone edema level of over 1/3, and their associated risks versus no injury cases were 14.1, 3.7, 6.8, and 10.4-fold, respectively. CONCLUSIONS AL injury, superior endplate and disc injury, or a high level of bone edema, were critical factors that determine kyphotic deformity progression.