Analysis of the independent risk factors of neurologic deficit after thoracolumbar burst fracture

BACKGROUND The objective of this study is to identify the independent risk factors of neurologic deficit after thoracolumbar burst fracture. Traumatic fractures of the thoracolumbar spine are the most common type of spinal column fractures. Many studies have attempted to determine whether neurologic deficit in such fractures is related to spinal canal stenosis or other parameters observed on axial computed tomography. However, this relationship remains controversial. METHODS A review of the clinical data and axial computed tomography (CT) for 105 patients was performed. Neurologic deficit was classified according to the American Spinal Injury Association (ASIA) classification. Various preoperative CT parameters, including vertebral body compression, canal stenosis, sagittal alignment, and fragment reverse, were analyzed using ordinal logistic regression analysis. RESULTS Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification, canal volume, transverse canal diameter, median sagittal diameter, Cobb angle, compression ratio of the sagittal diameter, compression ratio of the cross-sectional area, and compression ratios of the anterior vertebral height (AVH), middle vertebral height (MVH), and posterior vertebral height (PVH) were significantly associated with severity of nerve injury (P < 0.05). However, flip angle and rotation angle of bony fragments were unrelated to severity of nerve damage. Multivariate logistic regression identified AO classification, compression ratio of median sagittal diameter, anterior vertebral compression ratio, and distance from the posterior margin to the vertebral body above to be independent variables associated with neurologic deficit. CONCLUSIONS The four CT parameters most strongly associated with neurologic deficit in thoracolumbar burst fractures are AO classification, compression ratio of median sagittal diameter, anterior vertebral compression ratio, and distance from the posterior margin to the vertebral body above.