经皮椎体成形术中骨水泥注射量与分布的生物力学研究

目的：明确低量的骨水泥灌注对于椎体生物力学性能的影响以及骨水泥的偏侧分布是否增加了椎体向未强化侧塌陷的风险。方法：自4具老年尸体取得胸腰段脊柱标本（T8-L3）。将标本游离成单个椎体，用材料试验机前屈加载，制成椎体压缩骨折模型。经2ml或4ml骨水泥中位或偏侧注射强化后，对椎体再度压缩获得强度与刚度数据。初始、压缩后和再度压缩后椎体的前后左右高度均被测得。结果：注入骨水泥后椎体强度均得到了恢复，而注射4ml骨水泥后的强度明显高于初始水平。刚度均未能得到相应的恢复，但4ml组刚度恢复的程度明显高于2ml组。椎体的高度在强化后与最终压缩后的变化比较差异无统计学意义。结论：低量的骨水泥灌注可以恢复椎体的强度，不能恢复椎体的刚度。骨水泥的偏侧分布未增加椎体向偏侧塌陷的风险。

Biomechanical Research on the Effect of Cement Volume and Placement of Percutaneous Vertebroplasty

Objective： To examine the effect of low - volume infusion of bone cement on mechanical - property of Vertebral bodies and to determine if placing the cement laterally rather than centrally resulted in risk of collapse on the nonaugmented side. Methods： Thoracolumbal vertebral bodies （ T8-L3） were harvested from four old cadavers, separated into individual vertebral bodies and then were compressed in a materials testing machine to determine their initial strength and stiffness. They were stabilized by injecting 2.0 or 4.0 mL of cement centrally or laterally and then were recompressed to determine their augmented strength and stiffness. Anterior, posterior,left, and right lateral heights were measured initially, after augmentation, and after recompression. Results：All the strength of vertebral bodies were restored after injected with bone cement and 4.0 - mL injections was significantly greater than it was initially. Although all the stiffness of vertebral bodies were not restored ,4.0 - mL injections was significantly more than 2.0 - mL injections. Vertebral heights did not significantly differ between the augmented and the final compression. Conclusion： Low- volume infusion of bone cement could restore the strength of vertebral bodies, but not of the stiffness. Vertebral bodies in which cement is placed laterally do not appear to be at risk for collapse on the unaugmented side.