چكيده به لاتين
Background: Long-segment fusion in high-grade lumbosacral spondylolisthesis is one of favorite options for surgeons. Several fusion failures because of sacral screw fracture is reported. To overcome this kind of complications associated with fusions ending at S1, sacropelvic fixation using iliac screws has been introduced as a safe alternative.
Objective: This study is proposed to find if using iliac screws in long fusions result is a more reliable treatment of high-grade lumbosacral spondylolisthesis. Hence, the main purpose is evaluation of sacropelvic fixation to see if it has a significant effect on stress distribution in lumbosacral screws and their surrounding bone, especially at the first sacral vertebrae (S1).
Methods: An FE model of the spinopelvic (L3-Pelvis), which included three vertebrae, three discs, and a pelvis, was reconstructed. The geometrical specifications of the spinopelvic were obtained from 64 spiral CT images of a 50-years-old male patient with sacropelvic fixation and a long-segmental lumbosacral fusion from L4 to S1 to manage his high-grade spondylolisthesis resulting in a stabilized spinal column.
Results: Using iliac screws for spinopelvic fixation resulted in significant reduction of maximum von-mises stress in structural fusion, both in pedicular screws and surrounding/contact bones. Reduction of about 35% of maximum von-mises stress has a considerable effect, especially to avoid fracture of pedicular screw in sacrum.
Conclusion: To overcome the complications associated with long fusions ending at S1, sacropelvic fixation with iliac screws has been introduced as a safe alternative. Although this technique provides powerful control of the pelvis and significant reduction of loads/stresses especially in pedicular screws, surgical planning should be comprehensively analyzed because of extensive subfascial dissection in order to expose the posterior-superior iliac spine during implant insertion which can caused complications.
