Comparison of a Fluoroscopic Three Dimensional Imaging System and Conventional CT in Detection of Pars Fractures in the Cadaver

INTRODUCTION: Lumbar spondylolysis is defined as a defect or fracture of the pars interarticularis and can occur with or without anterior spondylolisthesis. This lesion is suspected to arise from repetitive trauma to the posterior elements of the spine and is a major cause of back pain in children; spondylolysis is found in approximately 6% of the pediatric/adolescent population as a whole and up to 15% of adolescent athletes. Cross-sectional imaging is often used to identify and characterize this condition and computed axial tomography (CT scan) is currently the gold standard exam for determining whether a fracture is present. While widely used, CT scan has several drawbacks which limit its application. Conventional CT scans are obtained with the patient lying supine on the scanning table, a position which may result in partial or complete reduction of an anterolisthesis and thus partially mask the severity of the condition. Furthermore, CT scan uses ionizing radiation which limits the frequency that follow-up scans can be obtained to monitor the progress of this condition. New fluoroscopic imaging systems with multiplanar capabilities can be used with the patient in a standing, weight-bearing position and may provide equivalent imaging with less radiation exposure. This study had three objectives: 1) To validate a fluoroscopic multiplanar imaging in identification of simulated spondylolytic fractures through the parts interarticularis in cadaveric lumbar vertebrae; 2) To compare sensitivity and specificity of spondylolysis identification between this fluoroscopic imaging system, plain radiographs and conventional CT scan; and 3) To compare radiation dose between these three imaging modalities.