不同长度钛笼植骨对山羊椎体融合的影响

Effect of titanium cage implantation with different lengths on vertebral fusion in goat model

中文关键词:  钛笼植骨  椎体融合  生物力学  山羊

英文关键词:Titanium cage bone graft  Vertebral fusion  Biomechanics  Goat

中文摘要:

  【摘要】 目的：通过切除不同长度的山羊椎体，构建腰椎切除的山羊模型，观察不同长度的钛笼对椎体植骨融合的影响。方法：成年山羊15只，体重25~35kg，随机分成3组，每组5只，构建经前路L3椎体为中心腰椎椎体切除融合的山羊动物模型，根据切除椎体长度分为A组（切除0.5个椎体）、B组（切除1个椎体）和C组（切除1.5个椎体），选取合适长度钛笼，将切除的椎体去除软组织后钛笼植骨。术后14d静脉采血，比较骨钙素（bone gla protein，BGP）、骨碱性磷酸酶（bone alkaline phosphatase，BALP）、骨形态蛋白（bone morphogenetic protein-2，BMP-2）、转化生长因子β（transforming growth factor-β，TGF-β）、血管内皮生长因子（vascular endothelial growth factor，VEGF）3组间的表达水平。4个月后处死山羊，测定钛笼内距骨接触面不同距离（0mm，5mm，10mm）椎体的相对CT值，分析植骨愈合情况。利用力学测试仪检测椎体标本前屈、后伸、侧弯、扭转等不同运动状况下的变形及位移，三维CT扫描提供的数据造模，进行有限元分析。丽春红染色观察钛笼内距骨接触面不同距离骨小梁生长情况。结果：术后14d，A组的BGP、BALP、BMP-2、TGF-β和VEGF表达水平（OD值分别是0.271±0.032、0.522±0.060、0.306±0.046、0.314±0.055和0.364±0.033）均显著低于B组（OD值分别是0.657±0.085、1.360±0.145、0.775±0.065、0.767±0.068和1.037±0.039）和C组（OD值分别是0.664±0.041、1.348±0.113、0.741±0.066、1.038±0.079和1.280±0.067）（P＜0.05）。A、B、C三组钛笼和骨接触面0mm处相对CT值分别为0.82±0.13、0.75±0.12、0.40±0.06，距离骨接触面5mm处相对CT值分别为0.57±0.11、0.52±0.03、0.26±0.05，距离骨接触面10mm处，相对CT值分别为0.42±0.07、0.28±0.08、0.14±0.03，与距接触面0mm处比较，5mm处、10mm处相对CT值均存在统计学差异（P＜0.05）。生物力学检测和有限元分析法显示：A、B、C三组在扭矩为1N·m时，扭角分别为1.23±0.12、2.53±0.19、3.93±0.27，扭矩为3N·m时，扭角分别为4.05±0.39、10.26±0.90、13.78±0.81，扭矩为5N·m时，扭角分别为8.65±0.69、21.15±1.62、26.45±2.29。各组之间均存在统计学差异（P＜0.05）。结论：较短的钛笼植骨山羊模型中外周血中促进骨生长相关因子表达低，植骨区域融合强度大，椎体间稳定性好。组织学切片检测显示钛笼内骨小梁生长情况随距离钛笼界面的距离越远，骨小梁的生长情况逐渐变差，而且随着钛笼的变长，钛笼内骨小梁生长也变得越差。

英文摘要:

  【Abstract】 Objectives: To study the effect of implantation of different lengths of titanium cage on the bone graft fusion of vertebral body, and to construct the lumbar vertebra resection model by removing the different length of goat vertebra. Methods: A total of 15 goats were randomly divided into 3 groups, 5 goats in each group, an animal model was constructed by means of anterior extraperitoneal approach. According to the length of the resected vertebral body, the goats were divided into group A(removal of 0.5 vertebral body), group B(removal of 1 vertebral body) and group C(removal of 1.5 vertebral bodies). The venous blood samples were taken at fourteenth days to detect the levels of BGP, BALP, BMP-2, TGF-β and VEGF. The goats were sacrificed 4 months after the artificial feeding. The bone healing in different lengths of titanium cage was analyzed by imaging, and the growth of trabecular bone in different length position from the titanium cage and bone contact surface was observed by tissue dying. The deformation and displacement of vertebral body under different motion conditions such as flexion, extension, lateral bending and torsion were detected by mechanical testing instrument. The data provided by three-dimensional CT scanning were used for finite element analysis. Results: At the fourteenth day, the expression levels of BGP, BALP, BMP-2, TGF-β and VEGF in group A(the OD values were 0.271±0.032, 0.522±0.060, 0.306±0.046, 0.314±0.055 and 0.364±0.033) were significantly lower than those in group B(the OD values were 0.657±0.085, 1.360±0.145, 0.775±0.065, 0.767±0.068 and 1.037±0.039) and group C(the OD values were 0.664±0.041, 1.348±0.113, 0.741±0.066, 1.038±0.079和1.280±0.067)(P＜0.05). The CT values in the contact surface of titanium cage and bone trabecular of A, B, C groups were 0.82±0.13, 0.75±0.12 and 0.40±0.06, respectively. However, the distance of bone contact surface was 10mm, CT values decreased to 0.42±0.07, 0.28±0.08, 0.14±0.03, compared with the 0mm point, there were significant differences in three groups(P＜0.05). Imaging results showed that the trabecular bone in titanium cage was less than the trabecular bone in interface, and the longer the titanium cage was, the worse the trabecular growth was. The biomechanical test and finite element analysis showed that the longer the fixed section was, the smaller the mobility was, the worse the deformation resistance was. Histological analysis showed that the farther the distance from titanium cage interface, the worse the bone trabecula growth, and as the titanium cage longer, the growth of bone trabecula in titanium cage became worse, indicating that titanium cage was longer, the bone trabecular density of same length position from titanium cage and bone contact surface was small. Conclusions: The shorter the length of the titanium cage bone, the better the bone growth, the lower the expression of inflammatory factors, the better the vertebral mobility.