改良Galveston技术与拉力螺钉固定单侧骶髂关节脱位的有限元分析

Objective To explore biomechanical properties of modified Galveston technique and lag screw fixation for dislocation of the unilateral sacroiliac ioint through finite element analysis. Methods Soft-ware Mimics 10.0l and Geomagic 10.0 was used to develop a geometric reconstruction of the pelvis based on the CT scan data.Geometric reconstructions of different internal fixations were also developed using software Solidworks 2007.The models were meshed,assembled and given the material properties through software Hypermesh 10.0.Five models of three-dimensional finite element(3D FE)were established for dislocation of the sacroiliac ioint:double L4-ilium Galveston fixation,double L5-ilium Galveston fixation,single L4-ilium Galveston fixation.single L5-ilium Galveston fixation,and lag screw fixation,Finally the models were imported to software Ansys 10.0.An axial load of 500 N was compressed above the L4 vertebral body.Stress-strain nephograms for the 5 different fixations were compared.and biomechanical stabilities of different internal fixations were analyzed. Results The stress-strain nephograms showed the maximum pelvic stresses in the 5 fixations were respectively 1.690×109Pa(double L4-1 Galveston),1.130×109Pa(double 1.584×109Pa(1ag screw fixation).Displacements of the sacrum were downward,forward,and rightward.The total displacements were respectively 1.589×10-3m,1.871×10-3m,2.404×10～m,2.468×10-3m and 0.308 ×103 m. Conclusions The maximum displacement in bilateral fixation is smaller than that in unilateral fixation with modified Galveston technique.In both bilateral and unilateral Galveston fixations for L4and L5,the maximum displacements are not significantly different,but they are larger than that in lag screw fixation.

Modified Galveston technique and lag screw fixation for dislocation of the unilateral sacroiliac joint:a finite element analysis