摘要
目的探讨腰椎单侧椎弓根体部无移位型骨折经伤侧椎弓根置入椎弓根螺钉对伤椎椎弓根和临近椎体生物力学的影响。方法基于正常成人L_(4～5)椎体的CT扫描影像资料,通过Mimics软件建立L_4椎体腰椎单侧椎弓根体部无移位型骨折模型(以下称L_4椎体骨折模型)。将制作好的L_4椎体骨折模型与L_5椎体以stl格式导入3-matic中建立椎间盘并进行网格划分。参照以上步骤,CT扫描椎弓根螺钉后建立三维实体模型并划分网格。将L_4椎体骨折模型置入椎弓根螺钉前后赋予材料属性,并导入Ansys有限元分析软件中,运用弹簧单元功能模拟韧带。固定L_5椎体底部,分别在置入椎弓根螺钉前后于L_4椎体上表面施加500 N应力,模拟生理情况下椎体承受垂直载荷的受力情况,并给予10 N/m力矩,模拟椎体垂直、前屈、后伸、左屈、右屈、左旋、右旋活动工况,获得L_4椎体在置入椎弓根螺钉前后L_5椎体的应力分布,L_4椎弓根应力分布以及椎弓根螺钉前、中、后部应力分布情况。结果L_4椎体经伤侧椎弓根置入椎弓根螺钉后,L_5椎体在后伸位所受应力最大。置入椎弓根螺钉后,后伸工况时伤椎椎弓根所受应力较置入椎弓根螺钉前明显降低(P <0. 05),其所受应力主要集中于椎弓根螺钉中部。在腰椎左旋、右旋工况时,伤椎椎弓根所受应力均较术前增加,椎弓根螺钉在旋转运动时承受应力最高,应力集中于骨折断端处,而下位椎体承受应力较术前明显降低(P均<0. 05)。椎体在垂直、前屈、左弯、右弯工况时,椎弓根螺钉置入前后伤椎椎弓根及临近椎体应力均无明显变化(P均> 0. 05)。结论腰椎单侧椎弓根体部无移位型骨折经伤椎置钉可减轻骨折断端所受应力,提高其稳定性,促进骨折愈合,但需适度限制腰椎后伸、左旋、右旋运动。
Objective To investigate the effect of pedicle screw placement through the injured side on the biomechanics of injured vertebral pedicle and adjacent vertebral body in the unilateral pedicle of the lumbar vertebra.Methods Based on the CT scan image data of normal adult L4-5vertebral body,the unilateral pedicle screw displacement model of L4vertebral body was established by Mimics software(the following is called the L4vertebral fracture model).The prepared L4vertebral fracture model and the L5vertebral body were introduced into the3-matic in the stl format to establish the intervertebral disc and then we did the mesh generation.Referring to the above steps,we used the CT scan of the pedicle screw to create a three-dimensional solid model and meshed it.We imparted the L4vertebral fracture models material propertiesas before and after the pedicle screws were placed,and were introduced into the Ansys finite element analysis software to simulate the ligament using the spring unit function.The bottom of the L5vertebral body was fixed,and500N stress was applied to the upper surface of the L4vertebral body before and after the pedicle screw was inserted.The force of the vertebral body under vertical load was simulated under physiological conditions,and a torque of10N/m was given to simulate the vertebra.We simulated the activity of the vertebral body in vertical,anteflexion,backward extension,left flexion,right flexion,left spin,and right spin.The stress distribution of the L5vertebral body before and after the placement of the pedicle screw,the stress distribution of the L4pedicle and the stress distribution of the anterior,middle and posterior pedicle screws were obtained.Results After the pedicle screw was inserted into the L4vertebral body through the injured pedicle,the L5vertebral body was most stressed in the posterior extension.After the pedicle screw was placed,the stress of the injured vertebral arch was significantly lower than that before the pedicle screw was inserted(P<0.05),and the stress was mainly conce
作者
文毅
马朋朋
苏峰
宗治国
李月轩
毛振
张志敏
WEN Yi;MA Pengpeng;SU Feng;ZONG Zhiguo;LI Yuexuan;MAO Zhen;ZHANG Zhimin(Hebei North University, Zhangjiakou 075000, China)
出处
《山东医药》
CAS
2018年第44期5-8,共4页
Shandong Medical Journal
基金
河北省省级重大医学科研课题(zd2013050)
关键词
腰椎椎弓根骨折
椎弓根螺钉内固定术
三维有限元分析
lumbar pedicle fracture
pedicle screw internal fixation
three-dimensional finite element analysis
