经椎间孔椎间融合术与Coflex棘突间固定装置的生物力学仿真

Biomechanical Simulation on Transforaminal Lumbar Interbody Fusion and Interspinous Process Device Coflex

本文的目的是研究比较经椎间孔椎间融合术(transforaminal lumbar interbody fusion, TLIF)与腰椎棘突间Coflex动态固定装置的腰椎术后生物力学性能,为腰椎术式的临床应用与改进创新提供借鉴。基于医学影像数据建立人体腰骶椎L3-S1节段有限元模型,并结合临床手术方案建立TLIF与Coflex术后有限元模型,模拟腰骶椎的屈伸、侧弯与旋转运动,比较不同工况下的腰椎活动度与器械应力分布。仿真结果表明,TLIF与Coflex术式对责任节段屈伸活动度的限制作用相近,TLIF术式对责任节段侧弯运动的限制作用更强,对邻近节段活动度的影响更为显著;两类内固定器械的最大应力都发生在后伸运动下,且TLIF钉–棒系统的总体应力更高,在术后应尽量避免过度的后伸运动,降低器械的断裂风险。

This study aimed to investigate and compare the lumbar biomechanical characteristics after trans-foraminal lumbar interbody fusion (TLIF) and lumbar interspinous process device Coflex, and provided reference for clinical application and innovation of lumbar spine surgery. The finite element (FE) model of L3-S1 lumbosacral spine was constructed based on the medical image data, and the FE models of TLIF and Coflex were established based on the clinical guidelines. The range of motion (ROM) of the lumbar spine and stress distributions on instruments were observed in extension, flexion, lateral bending, and axial rotation motions. Results showed that the TLIF and Coflex had a similar influence on the lumbar flexion-extension ROM, and TLIF had a stronger effect on the lateral bending motion for surgical segment, and more significant effect on the ROM of the adjacent segments. Furthermore, the maximum stress of two fixation instruments both occurred in extension motion, and the overall stress of the TLIF nail-rod system was higher than Coflex, thus, the excessive extension motion should be avoided to minimize the risk of device fracture.