Knop C, Lange U, Bastian L, Oeser M, Blauth M
Department of Trauma Surgery, Hannover Medical School, 30623 Hannover, Germany.
Eur Spine J. 2001 Feb;10(1):30-7. doi: 10.1007/s005860000211.
The authors present an investigation into the biomechanical functioning of a new titanium implant for vertebral body replacement (Synex). Possible indications are fractures and/or dislocations with damage of the anterior column, posttraumatic kyphosis and tumors of the thoracolumbar spine. The construction must be supplemented by a stabilizing posterior or anterior implant. For best fit and contact with adjacent end-plates, Synex is distractable in situ. We performed comparative compression tests with Synex and MOSS ("Harms mesh cage") on human cadaveric specimens of intact vertebrae (L1). The aim of the study was to measure the compressive strength of the vertebral body end-plate in uniaxial loading via both implants to exclude collapse of Synex in vivo. Twelve human cadaveric specimens of intact vertebrae (L1) were divided into two identical groups (matched pairs) according to bone mineral density (BMD), determined using dual-energy quantitative computed tomography (DE-QCT). The specimens were loaded with an axial compression force at a constant speed of 5 mm/min to failure, and the displacement was recorded with a continuous load-displacement curve. The mean ultimate compression force (Fmax) showed a tendency towards a higher reading for Synex: 3396 N versus 2719 N (non-significant). The displacement until Fmax was 2.9 mm in the Synex group, which was half as far as in the MOSS group (5.8 mm). The difference was significant (P < 0.001). The compression force was twice as high, and significantly (P < 0.05) higher with Synex at displacements of 1 mm, 1.5 mm and 2 mm. A significant (P < 0.001) correlation (R = 0.89) between Fmax and BMD was found. Synex was found to be at least comparable to MOSS concerning the compressive performance at the vertebral end-plate. A possible consequence of the significantly higher mean compression forces between 1 and 2 mm displacement might be decreased collapse of the implant into the vertebral body in vivo.
作者介绍了一种用于椎体置换的新型钛植入物（Synex）生物力学功能的研究。可能的适应症包括前柱损伤的骨折和/或脱位、创伤后脊柱后凸以及胸腰椎肿瘤。该结构必须辅以稳定的后路或前路植入物。为了与相邻终板实现最佳贴合和接触，Synex可在原位进行撑开。我们对完整椎体（L1）的人体尸体标本进行了Synex和MOSS（“哈姆斯网笼”）的比较压缩试验。该研究的目的是通过两种植入物测量椎体终板在单轴加载下的抗压强度，以排除Synex在体内塌陷的情况。根据使用双能定量计算机断层扫描（DE-QCT）测定的骨矿物质密度（BMD），将12个完整椎体（L1）的人体尸体标本分为两个相同的组（匹配对）。以5mm/min的恒定速度对标本施加轴向压缩力直至破坏，并通过连续的载荷-位移曲线记录位移。平均极限压缩力（Fmax）显示Synex有更高读数的趋势：3396N对2719N（无统计学意义）。Synex组达到Fmax时的位移为2.9mm，仅为MOSS组（5.8mm）的一半。差异具有统计学意义（P<0.001）。在1mm、1.5mm和2mm位移时，Synex的压缩力是MOSS的两倍，且差异具有统计学意义（P<0.05）。发现Fmax与BMD之间存在显著（P<0.001）相关性（R=0.89）。结果发现，Synex在椎体终板的抗压性能方面至少与MOSS相当。在1至2mm位移之间平均压缩力显著更高的一个可能结果是，植入物在体内向椎体塌陷的情况可能减少。
