摘要
目的研究生理载荷作用下,椎体成形术和椎体后凸成形术对邻近椎体应力、椎间盘压力的影响。方法基于健康成年男性T12-L1-L2节段CT图像,MSC.Marc软件建立T12-L1-L2节段骨质疏松有限元模型。L1椎体为楔形压缩骨折椎体,前缘高度较正常降低35%。模拟椎体成形术和椎体后凸成形术,在L1椎体内注入骨水泥。椎体后凸成形术L1椎体高度较正常降低10%,代表骨折椎体复位。观察直立位时,上身重力(260N)、随动载荷(200N)和竖脊肌力作用下,椎体成形术和椎体后凸成形术之竖脊肌力、邻近椎体最大von Mises应力、椎间盘压力变化。结果①与骨折前比较,椎体成形术和椎体后凸成形术竖脊肌力分别增高183%、56%,邻近椎体最大von Mises应力分别增高81%、27%,椎间盘压力分别增高61%、22%。②无论骨折与否,L1椎体骨水泥强化以后邻近椎体应力、椎间盘压力分别增高2.2%～2.6%、3.3%～3.6%。结论椎体楔形骨折使重力弯矩和竖脊肌力增大,造成椎体和椎间盘承载明显增加,骨水泥强化的影响相对较小。椎体后凸成形术纠正后凸畸形,降低了脊柱负载。
Objective To determine the effects of vertebroplasty and kyphoplasty on adjacent vertebral body stresses and intradiscal pressure under physiological load that includes muscle forces. Methods A three-dimensional finite element model of the osteoporotic thoracolumbar spine （T12-L1-L2） was created by MSC.Marc software. A wedgeshaped L1 vertebral body was simulated in finite element models. For the vertebroplasty （kyphoplasty） model, an anterior height of L1 vertebral body was reduced by 35% （10%）, related to the intact one. In order to simulate ＂standing＂, the models were loaded with the upper body weight （260N）, a follower load （200N）, and the force in the m. erector spinae. The force in the m. erector spinae, intradiscal pressure, and maximum von Mises stress in the adjacent vertebral bodies were investigated. Results ①The force in the m. erector spine increased by 183% for vertebroplasty and by only 56% for kyphoplasty compared to the intact spine. Maximum von Mises stress in the adjacent vertebral bodies increased by 81% and 27% for vertebroplasty and kyphoplasty, respectively. Intradiscal pressure increased by 61% and 22% for vertebroplasty and kyphoplasty, respectively. ②Bone cement augmentation had a much smaller effect on intradiscal pressure and vertebral body stresses. Conclusion The effect of upper body shift after a wedge-shaped vertebral body fracture on spinal loads was more pronounced than that of stiffness due to cement infiltration. The advantages of kyphoplasty found in this study will be apparent only if nearly full fracture reduction is achieved.
出处
《中国药物与临床》
CAS
2008年第9期705-707,共3页
Chinese Remedies & Clinics
基金
山西医科大学校青年基金资助项目(200503)
