Biomechanical rationale of sacral rounding deformity in pediatric spondylolisthesis: a clinical and biomechanical study
Biomechanical rationale of sacral rounding deformity in pediatric spondylolisthesis: a clinical and biomechanical study
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DOI：
10.1007/s00402-010-1257-2
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发表时间：
2011-01
影响因子：
2.3
通讯作者：
T. Terai;K. Sairyo;V. Goel;N. Ebraheim;A. Biyani;Faizan Ahmad;A. Kiapour;Kosaku Higashino;T. Sakai;N. Yasui
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文献类型：
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作者：
T. Terai;K. Sairyo;V. Goel;N. Ebraheim;A. Biyani;Faizan Ahmad;A. Kiapour;Kosaku Higashino;T. Sakai;N. Yasui
目的峡部裂性腰椎滑脱患者骶椎穹隆表面圆整，椎体楔形变形是常见的临床表现。最近，一项动物研究表明，由于峡部缺损导致生物力学改变后，未成熟儿童椎体中的生长板受累可导致畸形。然而，这些畸形的病理机制和生物力学尚未阐明。为了证明，骶骨圆的畸形，观察到的儿童脊椎滑脱患者可以扭转，并了解从生物力学的角度来看，通过分析应力的变化，周围的生长板的椎体由于spondylozy. Methods三维有限元小儿腰椎模型的L3-L5段的畸形的病理机制。与成人模型不同，该儿科模型具有生长板和骨突环。我们分析了351°N轴向压缩和屈曲、伸展、侧弯和轴向旋转时10 N m力矩的应力分布。在L4节段的模型中创建双侧椎弓峡部裂。在双边缺陷模型中的应力进行了比较，以完整的模型的预测和结果在儿童患者骶骨rounding modified.ResultsTwo患者提出了在S1在首次访问的前上角的圆形畸形。他们被要求停止体育活动，并使用柔软的躯干支架。12个月后，在X线片上未观察到圆形畸形，表明这种畸形在儿科病例中是可逆的。生物力学研究表明，在小儿峡部裂脊柱，机械应力增加在前上角在腰椎motion.ConclusionIn存在峡部裂，机械应力增加在生长板在前上角。反复增加的机械应力可能会导致骶骨圆顶变圆畸形介导的生长板参与。当生长板处的机械应力通过佩戴支具而减少时，生长板的正常功能可以帮助将骶骨圆顶重塑到其正常形状。
AimRounding surface of the sacral dome and wedging deformity of the vertebral body are commonly observed in patients with isthmic spondylolisthesis. Recently, an animal study showed that the deformity can be caused by the growth plate involvement in the immature pediatric vertebral body after biomechanical alteration due to the pars defects. However, the pathomechanism and biomechanics of these deformities have yet to be clarified. To demonstrate that the sacral rounding deformity observed in pediatric patients with spondylolisthesis can be reversed, and to understand the pathomechanism of the deformity from the biomechanical standpoint by analyzing changes of stress around the growth plate of the vertebral body due to spondylolysis.MethodThree-dimensional finite element pediatric lumbar models of the L3–L5 segment were utilized. Unlike the adult model, this pediatric model had growth plates and apophyseal rings. We analyzed stress distribution in response to 351°N axial compression and 10 N m moment in flexion, extension, lateral bending, and axial rotation. Bilateral spondylolysis was created in the model at the L4 level. The stress in the bilateral defect model was compared to the intact model predictions and the results obtained in the pediatric patients with sacral rounding deformity.ResultsTwo patients presented rounding deformity of the anterior upper corner at S1 at the initial visit. They were asked to stop sports activities and use a soft trunk brace. Twelve months later, no rounding deformity was observed on the radiographs indicating that this deformity was reversible in pediatric cases. The biomechanical study indicated that in the pediatric spondylolytic spine, mechanical stress increased at the anterior upper corner during lumbar motion.ConclusionIn the presence of spondylolysis, mechanical stress increases in the growth plate at the anterior upper corner. Repetitive increases of mechanical stress may cause rounding deformity of the sacral dome mediated by growth plate involvement. When mechanical stress at the growth plate is reduced by wearing a brace, the proper functioning of the growth plate can help to remodel the sacral dome to its normal shape.