| Objective: The three-dimensional finite element model of Posttraumatic kyphosis was established by finite element method.Two kinds of osteotomy methods,transpedicular osteotomy and transpedicular osteotomy,were simulated by preoperative planning and design.The orthopedic effect of two kinds of osteotomy methods in the treatment of Posttraumatic kyphosis was discussed.The stress distribution of internal fixation equipment and adjacent segments of intervertebral disc was analyzed,and the possibility of postoperative complications was evaluated Size.Method: One case of Posttraumatic kyphosis was selected,and the imaging data were collected.According to the clinical classification and literature reports,the relevant operation methods were selected,using Mimics、Geomagic、Solidworks、Ansys Workbench established the three-dimensional finite element model of Posttraumatic kyphosis,and the osteotomy model was established by simulating the two osteotomy methods: Pedicle subtraction osteotomy(PSO)and Ponte osteotomy(Ponte).The finite element model was obtained by applying the load to simulate the orthopedic process,Collect and analyze the parameters of sagittal plane and the stress change data of pin bar and adjacent segment disc.Results(1)The three-dimensional finite element model of Posttraumatic kyphosis was successfully created with 760389 elements and 1165205 nodes.(2)Stress distribution of adjacent segments of the disc: the stress of the 7-8 disc is mainly concentrated in the front edge and the middle point of the front edge(PSO: 7.6942 MPa,Ponte: 7.7532 MPa);The stress of thoracic 12-lumbar 1 disc is mainly around the disc,especially at the leading edge,and the maximum stress is at the leading edge(PSO : 9.2542 MPa,Ponte : 9.6653 MPa).(3)The stress of the screw rod: the stress value of the right screw of the thoracic 9 is the largest(PSO : 367.37 MPa,Ponte : 434.82 MPa);the stress area of the left side of the thoracic 8 and9 vertebrae and the tail of the bilateral screws of the thoracic 12 vertebrae is large.(4)The maximum displacement of vertebral body was in lumbar vertebrae 1(PSO: 37.925 mm,Ponte:39.12mm);the values of TK,LL,Cobb angle were larger after PSO than after Ponte osteotomy;the values of SVA and TLK were smaller after PSO than after Ponte osteotomy(SVA was within the normal range).Conclusions(1)High quality 3D finite element model of Posttraumatic kyphosis can be established by using the finite element analysis method,and fine preoperative planning and design can be realized;(2)When the orthopedic load is the same,the displacement of lumbar vertebra 1 is the largest(the stress after Ponte osteotomy is greater than that after PSO osteotomy),and the stress of adjacent segment is concentrated in the front edge of intervertebral disc(the stress after Ponte osteotomy is greater than that after PSO osteotomy);the stress of screws on the left side of thoracic 8,9 and bilateral screw tail of thoracic 12 are large,but the maximum value is all on the right side of thoracic 9(Ponte osteotomy Greater stress after osteotomy than after PSO);(3)In the treatment of Posttraumatic kyphosis with sagittal balance,PSO osteotomy and Ponte osteotomy can achieve satisfactory orthopedic effect on the appearance of the spine under the same orthopedic load,and Ponte osteotomy is better than PSO osteotomy.If the osteotomy volume is considered,Ponte osteotomy can be selected first,but the stress of pin rod and adjacent segment disc after Ponte osteotomy is greater,and internal fixation occurs after operation The probability of definite failure and borderline kyphosis is higher. |
