Abstract：
OBJECTIVE: To compare the stability of a corticopedicular posterior fixation (CPPF) device with traditional pedicle screws for decompression and fusion in adult degenerative lumbar spondylolisthesis.
METHODS: Finite element analysis (FEA) was used in a validated model of grade 1 L4-L5 spondylolisthesis to compare segmental stability after laminectomy alone, laminectomy with pedicle screw fixation, or laminectomy with CPPF device fixation. A 500-N follower load was applied to the model and different functional movements were simulated by applying a 7.5-Nm force in different directions. Outcomes included degrees of motion, tensile forces experienced in the CPPF device, and stresses in surrounding cortical bone.
RESULTS: At maximum loading, laminectomy alone demonstrated a 1° increase in flexion range of motion, from 6.35° to 7.39°. Laminectomy with pedicle screw fixation and CPPF device fixation both reduced spinal segmental motion to ≤1° at maximum loading in all ranges of motion, including flexion (0.94° and 1.09°), extension (-0.85° and -1.08°), lateral bending (-0.56° and -0.96°), and torsion (0.63° and 0.91°), respectively. There was no significant difference in segmental stability between pedicle screw fixation and CPPF device fixation during maximum loading, with a difference of ≤0.4° in any range of motion. Tensile forces in the CPPF device remained ≤51% the ultimate load to failure (487 N) and stress in surrounding cortical bone remained ≤84% the ultimate stress of cortical bone (125.4 MPa) during maximum loading.
CONCLUSIONS: CPFF fixation demonstrated similar segmental stability to traditional pedicle screw fixation whereas tensile forces and stress in surrounding cortical bone remained below the load to failure.
METHODS: Finite element analysis (FEA) was used in a validated model of grade 1 L4-L5 spondylolisthesis to compare segmental stability after laminectomy alone, laminectomy with pedicle screw fixation, or laminectomy with CPPF device fixation. A 500-N follower load was applied to the model and different functional movements were simulated by applying a 7.5-Nm force in different directions. Outcomes included degrees of motion, tensile forces experienced in the CPPF device, and stresses in surrounding cortical bone.
RESULTS: At maximum loading, laminectomy alone demonstrated a 1° increase in flexion range of motion, from 6.35° to 7.39°. Laminectomy with pedicle screw fixation and CPPF device fixation both reduced spinal segmental motion to ≤1° at maximum loading in all ranges of motion, including flexion (0.94° and 1.09°), extension (-0.85° and -1.08°), lateral bending (-0.56° and -0.96°), and torsion (0.63° and 0.91°), respectively. There was no significant difference in segmental stability between pedicle screw fixation and CPPF device fixation during maximum loading, with a difference of ≤0.4° in any range of motion. Tensile forces in the CPPF device remained ≤51% the ultimate load to failure (487 N) and stress in surrounding cortical bone remained ≤84% the ultimate stress of cortical bone (125.4 MPa) during maximum loading.
CONCLUSIONS: CPFF fixation demonstrated similar segmental stability to traditional pedicle screw fixation whereas tensile forces and stress in surrounding cortical bone remained below the load to failure.
摘要：
目的：比较骨椎弓根后路固定（CPPF）装置与传统椎弓根螺钉在成人退变性腰椎滑脱减压融合术中的稳定性。
方法：在经过验证的1级L4-L5脊椎滑脱模型中使用有限元分析（FEA）来比较单行椎板切除术后的节段稳定性，椎弓根螺钉固定椎板切除术，或椎板切除术与CPPF装置固定。在模型上施加了500N的从动件载荷，并通过在不同方向上施加7.5Nm的力来模拟不同的功能运动。结果包括运动程度，CCPPF装置承受的拉力，和周围皮质骨的应力。
结果：在最大负载时，单独的椎板切除术显示屈曲运动范围从6.35°增加到7.39°。椎弓根螺钉固定和CPPF装置固定的椎板切除术在所有运动范围的最大载荷下都将脊柱节段运动减小至≤1°。包括屈曲（0.94°和1.09°），延伸（-0.85°和-1.08°），横向弯曲（-0.56°和-0.96°），和扭转（0.63°和0.91°），分别。在最大载荷下，椎弓根螺钉固定和CPPF装置固定之间的节段稳定性没有显着差异，在任何运动范围内差异≤0.4°。在最大载荷期间,CPPF装置中的拉伸力保持≤失效极限载荷(487N)的51%,周围皮质骨中的应力保持≤皮质骨极限应力(125.4MPa)的84%。
结论：CPFF固定显示与传统椎弓根螺钉固定相似的节段稳定性，而周围皮质骨的拉力和应力保持在失效负荷以下。
方法：在经过验证的1级L4-L5脊椎滑脱模型中使用有限元分析（FEA）来比较单行椎板切除术后的节段稳定性，椎弓根螺钉固定椎板切除术，或椎板切除术与CPPF装置固定。在模型上施加了500N的从动件载荷，并通过在不同方向上施加7.5Nm的力来模拟不同的功能运动。结果包括运动程度，CCPPF装置承受的拉力，和周围皮质骨的应力。
结果：在最大负载时，单独的椎板切除术显示屈曲运动范围从6.35°增加到7.39°。椎弓根螺钉固定和CPPF装置固定的椎板切除术在所有运动范围的最大载荷下都将脊柱节段运动减小至≤1°。包括屈曲（0.94°和1.09°），延伸（-0.85°和-1.08°），横向弯曲（-0.56°和-0.96°），和扭转（0.63°和0.91°），分别。在最大载荷下，椎弓根螺钉固定和CPPF装置固定之间的节段稳定性没有显着差异，在任何运动范围内差异≤0.4°。在最大载荷期间,CPPF装置中的拉伸力保持≤失效极限载荷(487N)的51%,周围皮质骨中的应力保持≤皮质骨极限应力(125.4MPa)的84%。
结论：CPFF固定显示与传统椎弓根螺钉固定相似的节段稳定性，而周围皮质骨的拉力和应力保持在失效负荷以下。
