硫酸钙骨水泥强化骨质疏松绵羊腰椎的生物力学研究

目的评价硫酸钙骨水泥(CSC)强化骨质疏松绵羊腰椎力学强度的效果。方法成年雌性绵羊4只,行去势手术后饲养1年,测量去势前后腰椎骨密度。取L2～5共16个椎体,分为CSC组和对照组,每组8个椎体。CSC组经椎弓根向椎体内注射CSC(2.0 ml),对照组不给于任何处理。CSC组于术后12周测量L2～5单个椎体的骨密度,然后处死绵羊。取出椎体行压缩实验,测量各组中椎体的最大压缩应力(σult)和能量吸收值(EAV)。结果去势1年后绵羊腰椎骨密度显著下降,与去势前比较差异有统计学意义(P<0.05),骨质疏松绵羊模型建立成功。注射CSC 12周后椎体骨密度(BMD)、σult、EAV均高于对照组(P<0.05),且椎体的σult和EAV均与BMD成正相关关系(P<0.05)。结论 CSC可以提高骨质疏松椎体的BMD,强化骨质疏松椎体的力学强度,有利于避免或减少骨质疏松椎体骨折的风险。

Biomechanical study on augmentation of osteoporotic sheep vertebrae with calcium sulfate cement:in vivo study

Objective To evaluate biomechanical performance of osteoporotic lumbar vertebral body augmented with calcium sulfate cement(CSC) in ovariectomized sheep.Methods Four female adult sheep were treated with bilateral ovariectomy.Bone mineral density(BMD) of lumbar vertebrae of all sheep was measured before the treatment and one year after of the treatment.L2~L5 of each sheep and total 16 vertebrae were grouped into CSC and blank group with 8 vertebrae in each group.In CSC group,vertebrae were augmented with CSC(2.0 ml) through transpedicular approach.There was no augmentation in blank group.Each vertebra BMD of L2~L5 in CSC group was measured 12 weeks later.Then all sheep were killed and L2~L5 were prepared for compression test.The ultimate compared stresses(σult)and energy absorption value(EAV)of each group were recorded.Results There was a significant decrease in average BMD of lumbar one year after ovariectomy(P<0.05).The osteoporotic lumbar vertebral experiment was successful.12 weeks after augmentation with CSC,BMD,σult and EAV in CSC group were significantly higher than those in blank group(P<0.05).There was a positive linear relationship between BMD and σult as well as between BMD and EAV(P<0.05).Conclusions Calcium sulfate cement can significantly increase BMD of osteoporotic vertebrae and enhance biomechanical strength,which will avoid or decrease the risks of osteoporotic vertebral fractures.