【摘要】 目的建立L1椎体爆裂骨折的有限元模型,分析比较经椎弓根椎体内植骨和经椎管椎体内植骨的应力分布。方法通过CT扫描、Mimics三维重建、ANSYS前处理等方法建立胸腰段T12~L2有限元模型,据此建立L1椎体爆裂骨折后经椎弓根椎体内植骨和经椎管椎体内植骨加椎弓根钉棒后路固定模型。并对模型在前屈、后伸、侧弯和旋转下加载350N/8Nm,观察分析应力分布情况。结果正常胸腰段、L1椎体爆裂骨折、经椎弓根植骨和经椎管植骨模型的等效应力峰值如下,前屈:6.89、54.10、8.03、5.92MPa;后伸:56.70、109.00、12.50、8.61 MPa;侧弯:6.83、47.50、11.30、3.60 MPa;旋转:23.80、112.00、13.10、7.65 MPa。未植骨时应力主要集中于螺钉的尾部和连接棒,植骨后应力明显降低,并向螺钉中部分散分布。结论两种植骨方式的模型均重建了伤椎的强度,增加即时稳定性,但经椎管椎体内植骨更充分、更有效减小内固定应力,增加其力学安全性,从生物力学角度是一种植得推广的术式。更多还原

【Abstract】 Objective To construct a finite element model(FEM)of first lumbar vertebral burst fracture,and compare the stress distributions between transpedicular grafting and transcanal grafting.Method The FEM of normal thoracolumbar segment T12~L2with first lumbar vertebral burst fracture was established through thin layer CT scan,three- dimensional reconstruction by using Mimics and ANSYS software,respectively.The model was fixed by the posterior pedicle screws.On the basis of the models,we subsequently generated another 2 models simulating 2 types of surgical techniques,transpedicular grafting(TPG)and transcanal grafting(TCG).The stress distribution of model was observed in the respective 4models when spine was exposed to a stress of 350N/8Nm in the position of flexion,extension,lateral bending and rotation.Results Through the static analysis of Ansys software,it was concluded 4 model under various conditions of equivalent stress nephogram,and display the equivalent stress peak,flexion:6.89,54.10,8.03,5.92 MPa;extension:56.70,109.00,12.50,8.61 MPa;lateral bending:6.83,47.50,11.30,3.60 MPa;rotation:23.80,112.00,13.10,7.65 MPa.Not concentrated stress at the time of bone graft screw of the tail and connecting rods,stress significantly decreased after bone graft,assuming a scattered distribution to the central screw.Conclusion Both of the 2 types of grafting procedure/technique can reconstruct the strength of injured vertebrae and enhance the instant stability.Nevertheless,the technique of transcanal grafting may offer a better mechanical performance through decreasing the stress on the internal fixation in a more adequate and efficient way.Therefore this study concludes that it is a better surgical technique worth of being popularized in clinic.更多还原