椎体后凸成形骨水泥注入对骨质疏松邻近腰椎生物力学的作用

Effect of percutaneous kyphoplasty bone cement injection on biomechanics of adjacent lumbar spine in animal models with osteoporosis

背景:术后邻近椎体继发性骨折是经皮椎体后凸成形骨水泥注入最常见的并发症,研究经皮椎体后凸成形骨水泥注入对骨质疏松邻近腰椎生物力学功能的影响对临床应用具有一定的指导意义。目的:分析经皮椎体后凸成形骨水泥注入对骨质疏松兔模型邻近腰椎生物力学功能的影响。方法:切除36只雌性新西兰大白兔双侧卵巢,建立L3椎体骨质疏松骨折模型,造模成功后随机均分为2组,实验组行椎体后凸成形骨水泥注入,对照组行开放复位内固定手术。术后5,10,15个月,检测L2、L4椎体骨密度及最大弯曲与压缩载荷,L3椎体前缘、后缘高度与L2及L4椎体平均高度的比值,L2与L4椎体矢状面Cobb角。结果与结论:实验组术后不同时间点的骨密度值及最大弯曲与压缩载荷、椎体高度比值均高于术前(P<0.05),矢状面Cobb角低于术前(P<0.05);对照组术后不同时间点的骨密度值、最大弯曲与压缩载荷均高于术前(P<0.05),椎体高度比值及矢状面Cobb角与术前比较无差异;实验组术后不同时间点的骨密度值及最大弯曲与压缩载荷、椎体高度比值均高于对照组(P<0.05),矢状面Cobb角低于对照组(P<0.05)。表明椎体后凸成形骨水泥注入可改善骨质疏松骨折邻近椎体的骨密度、承载能力及后凸角度。

BACKGROUND： Adjacent vertebral secondary fracture after operation is the most common complication of percutaneous kyphoplasty bone cement injection. Studying the effects of percutaneous kyphoplasty bone cement injection on biomechanical function of adjacent lumbar spine in animal model with osteoporosis will have some guiding significance for clinical practice. OBJECTIVE： To investigate the effects of percutaneous kyphoplasty bone cement injection on biomechanical function of adjacent lumbar spine in rabbit models with osteoporosis. METHODS： Thirty-six New Zealand female white rabbits were ovariectomized to establish L3 vertebral osteoporotic fracture model, and then randomly and evenly divided into control group（treated with open reduction and internal fixation operation） and experimental group（treated with percutaneous kyphoplasty bone cementinjection）. At the 5^th, 10 ^th and 15^ th months after operation, L2, L4 bone mineral density, L2, L4 maximum bending and compressive load, the ratio of anterior and posterior heights of L3 vertebrae to average height of L2 and L4 vertebrae, and the sagittal Cobb angle of L2 and L4 vertebrae were detected. RESULTS AND CONCLUSION： The bone mineral density, maximum bending and compressive load, vertebral height ratio at different time points after operation in experimental group were higher compared with the preoperative level（P〈0.05）. The sagittal Cobb angle in experimental group was smaller compared with the preoperative level（P〈0.05）. In the control group, the bone mineral density, maximum bending and compressive load at different time points after operation were all higher compared with preoperative level（P〈0.05）. There were no significant difference of the vertebral height ratio and sagittal Cobb angle compared with the preoperative level. The bone mineral density, maximum bending and compressive load, vertebral height ratio at different time points after operation in experimental group were higher compared with the control group（P〈0.05）. The sagittal Cobb angle was smaller compared with the control group（P〈0.05）. These results demonstrate that percutaneous kyphoplasty bone cement injection can better improve the bone density, carrying capacity and kyphosis of osteoporosis fractures adjacent vertebrae.