The effect of anterior-posterior shear on the wear of CHARITÉ total disc replacement.
The effect of anterior-posterior shear on the wear of CHARITÉ total disc replacement.
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DOI：
10.1097/brs.0b013e31823cbd6e
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发表时间：
2012-04-20
期刊：
影响因子：
3
通讯作者：
Hall RM
中科院分区：
文献类型：
--
作者：
Vicars R;Prokopovich P;Brown TD;Tipper JL;Ingham E;Fisher J;Hall RM
Charité腰椎全腰椎间盘置换术磨损率的体外研究目的探讨前后向剪切对Charité腰椎全腰椎间盘置换术体外磨损率的影响。目前的标准只规定了4个自由度(DOF)的输入来评估全关节盘置换术的体外磨损，尽管功能脊柱单位包含6个自由度。前后方剪切已被强调为一个重要的负荷，特别是在腰椎。先前的一项研究调查了前后剪切对ProDisc-L的影响，发现磨损率与四自由度磨损试验没有显著差异。6个Charité腰椎间盘安装在5自由度脊柱磨损模拟器中，并在4自由度(ISO18192)条件下进行测试。另外6个Charité腰椎间盘在5个自由度的条件下进行测试，包括4个自由度的条件加上+2/-1.5 mm的前后剪切位移。将位移先减小后增大2倍，以考察位移大小的影响。在磨损试验前后对盘片进行µCT扫描，并计算盘片的高度损失。将这些测量结果与从另一家机构扫描的Charite光盘上获得的相同测量结果进行了比较。4自由度磨损率(12.2±1.0 mg/MC)与ProDisc-L的4自由度磨损率无显著差异。在标准的5自由度条件下，磨损率显著增加(p<；0.01)，降低了5DOF(24.3±4.9 mg/MC)，增加了5DOF(29.1±7.6 mg/MC)。外植体的高度损失与体外测试的盘没有显著差异(p>；0.05)。Charité腰椎全盘置换的磨损测试输入增加了前后剪切，显著提高了磨损率，这与之前在ProDisc上进行的5自由度测试形成了直接对比。这项研究强调了临床相关测试方案的重要性，不同的设计理念可能会有不同的测试输入。
An in-vitro study of the wear rates of the Charité lumbar total disc replacement. To investigate the effect of anterior-posterior shear on the in-vitro wear rates of the Charité lumbar total disc replacement. Current standards prescribe only 4 degree of freedom (DOF) inputs for evaluating the in-vitro wear of total disc replacements, despite the functional spinal unit incorporating 6DOF. Anterior-posterior shear has been highlighted as a significant load, particularly in the lumbar spine. A previous study investigated the effect of an anterior-posterior shear on the ProDisc-L, finding that wear rates were not significantly different from 4DOF wear tests. 6 Charité lumbar discs were mounted in a 5 active DOF spine wear simulator and tested under 4DOF (ISO18192) conditions. 6 further Charité lumbar discs were tested under 5DOF conditions, consisting of 4DOF conditions plus an anterior-posterior shear displacement of +2/-1.5mm. The displacement was decreased and then increased by a factor of 2, to investigate the effect of the magnitude of displacement. µCT scans were taken of the discs before and after wear testing, and the height loss of the discs calculated. These were compared to the same measurements taken from explanted Charite discs, µCT scanned at another institution. 4DOF wear rates (12.2±1.0mg/MC) were not significantly different from 4DOF tests on the ProDisc-L. Wear rates were significantly increased (p<0.01) for ‘standard’ 5DOF conditions (22.3±2.0 mg/MC), decreased 5DOF (24.3±4.9 mg/MC) and increased 5DOF (29.1±7.6mg/MC). The height loss of the explants and in-vitro tested discs were not significantly different (p>0.05). The addition of anterior-posterior shear to wear testing inputs of the Charité lumbar total disc replacement increases the wear rate significantly, which is in direct contrast to the previous 5DOF testing on the ProDisc. This study highlights the importance of clinically relevant testing regimens, and that test inputs may be different for dissimilar design philosophies.