Mechanical Analysis of Notch-Free Pre-Bent Rods for Spinal Deformity Surgery
Mechanical Analysis of Notch-Free Pre-Bent Rods for Spinal Deformity Surgery
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DOI：
10.1097/brs.0000000000003269
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发表时间：
2020-03-15
期刊：
影响因子：
3
通讯作者：
Chiba, Akihiko
中科院分区：
文献类型：
--
作者：
Yamada, Katsuhisa;Sudo, Hideki;Chiba, Akihiko
研究设计。根据美国材料测试学会(ASTM)F2193静态和动态四点弯曲方法对脊柱棒进行的实验研究。目标。这项研究的基础假设是，与传统的有缺口的曲线杆相比，无缺口的曲线杆具有显著更高的极限载荷和疲劳强度。本研究旨在分析无缺口曲杆与常规缺口杆的力学性能。背景数据摘要。脊柱内固定融合术治疗脊柱畸形的目的是重新调整脊柱，保持脊柱的矫正和稳定，以获得关节融合术。虽然棒的曲率可能起到重要作用，但术中直棒的轮廓会导致棒上的凹槽，导致疲劳强度降低。方法：研究方法。商业生产的钛合金(Phi 6.0 mm)和钴铬合金(Phi 5.5 mm)脊柱棒根据ASTM F2193进行了四点弯曲试验。结果。弯曲脊柱棒的静态四点弯曲试验表明，钴铬合金棒的刚度明显高于钛合金棒。无缺口钴铬合金棒材的极限载荷显著高于常规缺口钴铬合金和钛合金棒材。动态四点弯曲试验表明，无缺口钴铬合金棒材在2500,000次循环时的最小力/位移值大于有缺口钴铬合金棒材。结论。无缺口弯曲钴铬合金棒可能在脊柱畸形手术后保持其曲率，降低断裂风险，并可克服传统有缺口棒的断裂和回弹等问题。
Study Design. Experimental study of spinal rod as per the American Society for Testing Materials (ASTM) F2193 methodology for static and dynamic four-point bending. Objective. The hypotheses underlying this study were that the notch-free, curved rod would have a significantly higher ultimate load and fatigue strength compared with conventional notched curved rods. This study aimed to analyze the mechanical properties of notch-free curved rods compared with conventional notched rods. Summary of Background Data. The goal of instrumented spinal fusion in the management of spinal deformities is to realign the spine and maintain the correction and stability in order to obtain arthrodesis. Although rod curvature could play an important role, intraoperative contouring of the straight rod induces notches into the rod, leading to decreased fatigue strength. Methods. Commercially produced titanium alloy (phi 6.0 mm) and cobalt chromium alloy (phi 5.5 mm) spinal rods were assessed by four-point bending tests in accordance with the ASTM F2193. Results. Static four-point bending tests for the curved spinal rods showed that cobalt chromium alloy rods had significantly higher stiffness compared with titanium alloy rods. Notch-free cobalt chromium alloy rods had a significantly higher ultimate load than the conventional notched cobalt chromium alloy and titanium alloy rods. The dynamic four-point bending test showed that force/displacement at a minimum force at 2,500,000 cycles was larger in the notch-free cobalt chromium alloy rod than in the notched cobalt chromium alloy rod. Conclusion. The notch-free curved cobalt chromium alloy rod is likely to maintain its curvature after spinal deformity surgery with a decreased risk of breakage and could overcome the problems of the conventional notched rod such as breakage and spring-back.