Anatomical research of the lumbar pedicle located by the facet joint and the spinous process

Objective To observe the quantitative relations of the superior facet and the spinous process to the pedicle center,providing anatomical parameters for the pedicle screw placement.Methods 100 Lumbar(L1-L5) CT scans and Lumbar lateral films were enrolled in this research to measure the relative relation of the medial margin of superior facet to the pedicle axis and the superior margin of the spinous process to the pedicle axis.Meanwhile,the lower margin of the inferior facet's and the basilar part of the spinous process' distribution probability in the lumbar pedicle's division were counted.All the data were analyzed to compare the statistical difference.Results Totally the posterior projection points of the pedicle axis were all located at the lateral enthesis margin of the superior facet.The relative position among the superior facet,the spinous process and the pedicle axis were constant.Conclusion The superior facet and the spinous process can be used as references to guide the pedicle screw placement individually,which is simple,practical and has advantage when the facet joint complicated with osteophytes.