3rd Department of Orthopaedic Surgery, University of Athens, Medical School, Nikis 2, 14562 Kifissia, Athens, Greece; Baylor College of Medicine, Baylor Clinic, 6620 Main St, 13th floor, Suite 1325, Houston, TX 77030, USA.
Spine J. 2013 Dec;13(12):1921-7. doi: 10.1016/j.spinee.2013.06.054. Epub 2013 Aug 24.
Percutaneous vertebroplasty has been used successfully for many years in the treatment of painful compressive vertebral fractures due to osteoporosis.
To compare the effect of vertebroplasty on the compressive strength of unfractured vertebral bodies.
Biomechanical study on cadaveric thoracic vertebrae.
Forty vertebral bodies from four cadaveric thoracic spines were used for this experiment. Before testing, each thoracic spine was submitted to bone density testing and radiographic evaluation to rule out any obvious fractures. Under image intensification, 6 mL of a mixture of polymethylmethacrylate (PMMA) with barium (8 g of barium/40 g of PMMA) was injected into every other vertebral body of each spine specimen. After vertebroplasty, all soft tissues were dissected from the spine, and the vertebral bodies were separated and potted for mechanical testing. Testing to failure was performed using a combination of axial compression and anterior flexion moments. Two pneumatic cylinders applied anterior and posterior loads at a distance ratio of 4:3 relative to the anterior vertebral body wall, whereas two additional cylinders applied lateral loads, each at a constant rate of 200 N/s.
The average failure loads for nonvertebroplasty specimens was 6724.02 ± 3291.70 N, whereas the specimens injected with PMMA failed at an average compressive force of 5770.50 ± 2133.72 N. No statistically significant difference in failure loads could be detected between intact specimens and those that had undergone vertebroplasty.
Under these specific loading conditions, no significant increase in compressive strength of the vertebral bodies could be documented. This suggests that some caution should be applied to the concept of "prophylactic" vertebroplasty in patients at risk for fracture.
经皮椎体成形术已成功应用于治疗骨质疏松性压缩性骨折多年。
比较椎体成形术对未骨折椎体抗压强度的影响。
尸体胸椎的生物力学研究。
本实验使用了 4 具尸体胸椎的 40 个椎体。在测试之前，对每个胸椎进行骨密度测试和影像学评估，以排除明显的骨折。在影像增强下，将 6mL 聚甲基丙烯酸甲酯（PMMA）与钡（8g 钡/40g PMMA）的混合物注入每个脊柱标本的每两个椎体中。椎体成形术后，从脊柱上解剖所有软组织，并将椎体分离并进行盆栽进行力学测试。采用轴向压缩和前屈力矩相结合的方法进行失效测试。两个气动缸在距前椎体壁 4:3 的距离处施加前后负荷，而另外两个缸以恒定的 200N/s 速率施加侧向负荷。
非椎体成形术标本的平均失效负荷为 6724.02±3291.70N，而注入 PMMA 的标本在平均压缩力为 5770.50±2133.72N 时失效。未发现未行椎体成形术的标本与行椎体成形术的标本之间的失效负荷有统计学差异。
在这些特定的加载条件下，未发现椎体抗压强度有显著增加。这表明，对于有骨折风险的患者，“预防性”椎体成形术的概念应谨慎应用。
