球囊扩张椎体成形修复椎体压缩骨折的生物力学分析

背景：对于球囊扩张椎体成形的椎体压缩性骨折来说，临近椎体骨折到底是骨质疏松症进展的结果，还是椎体注入骨水泥干预和椎体强化的结果，目前生物力学研究和临床研究均存在争议，需要更深入的研究和更为长期的随访方可得出更为准确的结论。目的：评价球囊扩张椎体成形治疗对椎体压缩性骨折椎体及未强化临近椎体生物力学性能的影响。方法：制备40例猪椎体压缩骨折标本，随机分为研究组和对照组。研究组行球囊扩张椎体成形治疗，对照组仅采用生理盐水纱布包裹。比较两组标本的生物力学性能(椎体高度、最大载荷)以及500 N载荷下的应力、应变及位移值；另外测量观察组球囊扩张椎体成形治疗前和治疗后未强化临近椎体的应力值和应变值，并与对照组进行比较。结果与结论：与原始高度相比，研究组椎体行球囊扩张椎体成形治疗后能够恢复至原有高度，差异无显著性意义(P > 0.05)。比较研究组和对照组前、后、左、右的椎体高度，研究组显著高于对照组(P < 0.01)。研究组采用骨水泥强化后，刚度较对照组降低，最大载荷较对照组增加，差异有显著性意义(P < 0.05)。固定载荷500 N下，与对照组相比，研究组球囊扩张椎体成形治疗后椎间盘位移值显著降低，椎间盘应变值及应力值显著升高(P < 0.05)。比较观察组球囊扩张椎体成形治疗前和治疗后未强化临近椎体的应力值和应变值，差异均无显著性意义(P > 0.05)；观察组治疗后未强化临近椎体的应力值和应变值与对照组比较，差异无显著性意义(P > 0.05)。提示经球囊扩张椎体成形治疗椎体压缩骨折，椎体最大载荷和刚度的恢复状况良好，可达到预防椎体再次骨折的效果。同时球囊扩张椎体成形治疗并不能改变临近椎体的生物力学性能，难以影响并导致临近椎体的再次骨折，安全性较好。  中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Balloon vertebroplasty repairs vertebral compression fractures: biomechanical analysis

BACKGROUND: For vertebral compression fractures treated by balloon vertebroplasty, there were still controversies in biomechanical and clinical studies about adjacent vertebral fractures is the result of osteoporosis progress, or the result of vertebral intervention and strengthening by injecting bone cement. More accurate conclusions can be obtained through more in-depth research and long-term follow-up. OBJECTIVE: To evaluate the effect of balloon vertebroplasty on biomechanical properties of vertebral body with compression fractures and unstrengthened adjacent vertebral body. METHODS: Totally 40 pig specimens with vertebral compression fractures were prepared and randomly divided into study and control groups. Specimens in the study group were subjected to balloon vertebroplasty. Specimens in the control group only wrapped with normal saline gauze. The biomechanical properties (vertebral height, maximum load), stress, strain and displacement values of specimens under 500 N loading in these two groups were compared. The stress and strain values of unstrengthened adjacent vertebral body before and after the balloon vertebroplasty in the study group were measured, and compared with the control group. RESULTS AND CONCLUSION: Compared with the original height, specimens in the study group can restore to its original height after balloon vertebroplasty, the differences were not significant (P > 0.05). The former, back, left and right vertebral height in the study group were significantly higher than those in the control group (P < 0.01). After the bone cement augmentation, the stiffness of vertebral body in the study group was significantly lower than that in the control group, the maximum loading was significantly increased compared with that in the control group (P < 0.05). Under a fixed loading of 500N, compared with the control group, the disc displacement value after the balloon vertebroplasty was significantly reduced and the disc strain and stress values were significantly increased in the study group (P < 0.05). There were no significant differences in the strain and stress values of the unstrengthened adjacent vertebral body before and after the balloon vertebroplasty in the study group (P > 0.05). There were no significant differences in the strain and stress values of the unstrengthened adjacent vertebral body after the balloon vertebroplasty between study group and control group (P > 0.05). These results suggest that vertebral maximum loading and stiffness recover well after the treatment of balloon vertebroplasty for vertebral compression fractures, which can achieve the effect of preventing vertebral fractures again. Meanwhile, balloon vertebroplasty treatment can not alter the biomechanical properties of adjacent vertebrae, and it is difficult to influence and lead vertebral fractures again, with a better security.