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Table 1 Comparison of the classical and evaluated techniques

From: Evidence-based support for S1 transpedicular screw entry point modification

  Classical technique Evaluated technique
Preparation No particular preparation technique Preparing osteotomy
Entry point landmarks Not precisely defined Clearly defined
Individual interpretation at the entry point definition Possible Less likely
Technical difficulty More lateral exposure of the sacrum and soft tissue traction Less extensive lateral exposure demanded and soft tissue traction
Screw trajectory definition in the operating field Information cannot be drawn from local anatomy After osteotomy, S1 facet orientation is close to optimal screw trajectory
Ultimate screw trajectory Optimal Possible to be less convergent
Cortical bone thickness in normal, osteopenic and osteoporotic bone Decreasing lateralward Higher compared to lateral position
BMD values in normal, osteopenic and osteoporotic bone Decreasing lateralward Higher compared to lateral position
Implantation in degenerated spine No particular advantage Potential increase of the cortical thickness due to the proximity of the degenerated facet and spurs formation