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

目的 通过对改良Galveston技术与拉力螺钉同定单侧骶髂关节脱位的三维有限元模型进行分析,比较其生物力学稳定性.方法基于CT扫描数据,利用Mimics10.01软件和Geomagic10.0软件埘骨盆模型进行几何重建;利用Solidworks2007软件对内固定器械进行几何重建.导人Hypermesh 10.0软件中进行刚格划分和装配,赋予材料属性.建立右侧骶髂关节脱位双侧L4-髂骨Galveston固定、双侧L5-髂骨Galveston固定、单侧L4-髂骨Galveston同定、单侧L5-髂骨Galveston固定和拉力螺钉固定5种有限元模型.最后导入Ansys10.0软件中,在L4椎体上方模拟施加500 N轴向压缩载荷,分析不同内固定方式的von Mises应力分布和应变分布.结果从应力和应变云图可知,双侧L4-髂骨Galveston固定、舣侧L5-髂骨Galveston固定、单侧L4-髂骨Galveston固定、单侧L5-髂骨Galveston固定及拉力螺钉固定后骨盆的最大应力值分别为1.690×109 Pa、1.310×109 Pa、0.834×109 Pa、0.836×109 Pa、1.584×109 Pa;骶骨相对于左侧髋骨的移位方向为向下、向前和向右,总位移依次为1.589×10-3m、1.871×10～m、2.404×10-3 m、2.468×10-3m、0.308×10-3m.结论各种内固定下 Von Mises应力集中分布于腰髂螺钉与骨质的结合部位.改良Galveston技术双侧固定较单侧固定应变小,无论是双侧固定还是单侧固定,固定于L4和L5的应变无明显差异,但均明显大于拉力螺钉吲定.

Abstract：

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

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.