Comparison of L5 pedicle morphology in patients with and without L5 spondylolysis

Only a small number of studies have reported on L5 pedicle morphology in the presence of spondylolisthesis let alone isolated spondylolysis and findings are therefore variable. The aim of this radiographic study was to analyze L5 pedicle morphology in the presence and absence of L5 spondylolysis. The was a retrospective cross-sectional analysis of computed tomographic (CT) imaging. Assessment of the L5 pedicle morphology (height, width, length, transverse angle and screw length) were measured in patients with and without L5 spondylolysis. Pelvic measures including pelvic incidence, sacral anatomic orientation and sacral table angle were recorded. Patients were matched for age and gender. Twenty-three patients with spondylolysis were matched to 46 patients without. The presence of spondylolysis alone did not have a significant influence on either pelvic or pedicle morphologic parameters. Only with the presence of associated spondylolisthesis was there a difference noted with an increase in pedicle length observed. Correlation analysis suggested further morphologic changes may result with increased remodeling. Isolated spondylolysis at L5 appears to have little influence on pedicle morphology in this CT-based analysis. Morphologic changes appear likely to become significant only with associated spondylolisthesis and associated remodeling.