Higgins Kathryn B, Harten Robert D, Langrana Noshir A, Reiter Mitchell F
Department of Mechanical and Aerospace Engineering, Rutgers, the State University of New Jersey, Piscataway 08854, USA.
Spine (Phila Pa 1976). 2003 Jul 15;28(14):1540-7; discussion 1548.
To assess the biomechanical effects of unipedicular vertebroplasty on nonfractured vertebrae.
To evaluate the potential benefits of vertebroplasty as a preventative treatment. To evaluate the effects of cement volume and bone mineral density on the mechanics of augmented intact vertebral bodies.
Many studies have been undertaken to examine the effects of augmentation procedures such as vertebroplasty or kyphoplasty on fractured vertebral bodies. However, the role of such procedures as a prophylactic or interventional tool has not been well studied. This approach may be of clinical interest due to the high occurrence of secondary compression fractures and potentially altered biomechanics following an isolated vertebroplasty procedure.
Nonfractured osteoporotic vertebrae were measured to calculate volume and DEXA scanned to obtain bone mineral density information. Randomly selected specimens were injected with 10% and 20% bone cement by volume or left unfilled to serve as controls. After radiographs and noted cement leakage, specimens were subjected to destructive compression testing.
It was found that the injection of 20% bone cement by volume in the lumbar levels resulted in a statistically significant 36% strength increase as compared with the unfilled controls regardless of density levels. However, in the upper thoracic vertebrae there was no significant difference between the strengths of the three groups. Additionally, injection of 20% bone cement frequently resulted in extravasation through vascular channels or into the spinal canal.
The introduction of 20% bone cement by volume results in a significant increase in the compressive strength of intact lumbar vertebrae, however upper thoracic vertebrae do not demonstrate a similar strength improvement. There was no difference in the stiffness of the vertebrae injected with cement regardless of location. Bone mineral density (BMD) may play a role in the magnitude of the strength increase, with lower BMD specimens realizing a relatively greater strength improvement. Cement leakage was frequently noted with 20% cement injection, especially in the specimens with higher BMD. The location of the cement did not appear to have an effect on the loading behavior of the bone but should be controlled to minimize the chance of cement escaping into the spinal canal.
评估单侧椎体成形术对未骨折椎体的生物力学影响。
评估椎体成形术作为预防性治疗的潜在益处。评估骨水泥体积和骨密度对强化完整椎体力学性能的影响。
已经开展了许多研究来检验椎体成形术或后凸成形术等强化手术对骨折椎体的影响。然而，此类手术作为预防性或干预性工具的作用尚未得到充分研究。由于孤立椎体成形术后继发压缩骨折的高发生率以及潜在的生物力学改变，这种方法可能具有临床意义。
对未骨折的骨质疏松椎体进行测量以计算体积，并进行双能X线吸收法扫描以获取骨密度信息。随机选择的标本按体积注入10%和20%的骨水泥，或不注入作为对照。在进行X线检查并记录骨水泥渗漏情况后，对标本进行破坏性压缩试验。
发现无论密度水平如何，在腰椎节段注入20%体积的骨水泥与未注入的对照相比，强度在统计学上显著增加了36%。然而，在上胸椎，三组的强度之间没有显著差异。此外，注入20%骨水泥经常导致通过血管通道或进入椎管的渗漏。
按体积注入20%骨水泥可使完整腰椎椎体的抗压强度显著增加，但上胸椎未显示出类似的强度改善。无论位置如何，注入骨水泥的椎体刚度没有差异。骨密度（BMD）可能在强度增加的幅度中起作用，骨密度较低的标本实现相对更大的强度改善。注入20%骨水泥时经常注意到骨水泥渗漏，尤其是在骨密度较高的标本中。骨水泥的位置似乎对骨的加载行为没有影响，但应加以控制以尽量减少骨水泥漏入椎管的机会。
