Tschirhart C E Craig E, Nagpurkar Amik, Whyne C M Cari M
Orthopaedic Biomechanics Laboratory, Sunnybrook & Women's College Health Sciences Centre, Toronto, Ont., Canada.
J Biomech. 2004 May;37(5):653-60. doi: 10.1016/j.jbiomech.2003.09.027.
Spinal metastatic disease occurs in up to one-third of all cancer patients. Advanced spread can lead to vertebral burst fracture, which may result in neurologic compromise. Developing a better understanding of factors affecting burst fracture risk has significant clinical importance, as early intervention can prevent vertebral fracture in high-risk patients. The primary objective of this study was to quantify the effects of tumor location and shape on vertebral body stability and burst fracture risk in the metastatic spine using poroelastic parametric finite element modeling. This study also compared two distinct surface modeling techniques in the representation of lytic defects. A total of 16 ellipsoidal tumor scenarios were analyzed. Single tumors were situated in central, anterior, posterior, superior, inferior, and lateral locations, with smooth and serrated tumor surfaces. Two central shapes and two serrated surface multi-tumor scenarios were also analyzed. Outcome parameters of maximum vertebral bulge and axial displacement were assessed as representative of burst fracture risk. Posterior movement of the tumor caused the greatest increase in vertebral bulge. Tumor shape also affected burst fracture risk. The multi-tumor scenarios yielded the greatest reductions in both vertebral bulge and axial displacement. Serrated tumor scenarios abided by similar trends as smooth tumor scenarios, although tumor serration caused a slight increase in fracture risk. Tumor shape and volume are best controlled by smooth surface modeling. Improved understanding of factors contributing to metastatic burst fracture risk will aid in directing future modeling efforts and in the development of accurate risk assessment criteria.
脊柱转移性疾病在所有癌症患者中发生率高达三分之一。疾病的进展扩散可导致椎体爆裂骨折，进而可能导致神经功能受损。更好地了解影响爆裂骨折风险的因素具有重要的临床意义，因为早期干预可预防高危患者发生椎体骨折。本研究的主要目的是使用多孔弹性参数有限元模型量化肿瘤位置和形状对转移性脊柱中椎体稳定性和爆裂骨折风险的影响。本研究还比较了两种不同的表面建模技术在溶骨性缺损表现方面的差异。共分析了16种椭圆形肿瘤情况。单个肿瘤位于中央、前部、后部、上部、下部和外侧位置，肿瘤表面有光滑和锯齿状两种。还分析了两种中央形状和两种锯齿状表面多肿瘤情况。将最大椎体膨出和轴向位移的结果参数作为爆裂骨折风险的代表进行评估。肿瘤向后移动导致椎体膨出增加最多。肿瘤形状也影响爆裂骨折风险。多肿瘤情况导致椎体膨出和轴向位移的最大减少。锯齿状肿瘤情况与光滑肿瘤情况遵循相似趋势，尽管肿瘤锯齿状会导致骨折风险略有增加。肿瘤形状和体积最好通过光滑表面建模来控制。更好地了解导致转移性爆裂骨折风险的因素将有助于指导未来的建模工作和制定准确的风险评估标准。
