Chinese Journal Of Clinical Anatomy ›› 2016, Vol. 34 ›› Issue (1): 91-95.doi: 10.13418/j.issn.1001-165x.2016.01.023

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Finite element study on two kinds of bone grafting methods for the treatment of first lumbar vertebral burst fracture

LAN Mei-bing1, AO Jun2, ZHANG Mei-chao3   

  1. 1.Department of Anatomy, Zhuhai Campus of Zunyi Medical University, Zhuhai,Guangdong 519041,China; 2.Department of Spinal Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, China; 3.Department of Anatomy, Southern Medical University, Guangzhou 510515,China
  • Received:2015-09-21 Online:2016-01-25 Published:2016-01-28

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~L2 with 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 4 models 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.

Key words: Thoracolumbar, Burst fracture, Bone grafting, Finite element