Department of Urologic Surgery, University of Minnesota, Minneapolis, MN, USA.
J Endourol. 2012 Mar;26(3):271-4. doi: 10.1089/end.2011.0332. Epub 2011 Oct 19.
Extrinsic ureteral compression challenges a ureteral stent's ability to facilitate urinary drainage and to protect the kidney. Our purpose was to evaluate the performance of new metallic coil-based ureteral stents in terms of tensile strength and radial compression force.
Three stent designs tested from Prosurg Inc included Passage 7.0F, Snake 6.0F, and Snake 7.0F with the straight section covered with a biocompatible polymer tubing. A MTS Microbionix Testing System using Testworks II software, vibration isolation table, and a 5-N load cell were used to measure tensile and compressive strength. Stents were placed in hydraulic grips and stretched at a rate of 5 mm/s for 1 second under uniaxial tension. Extrinsic compression was exerted in 0.1-mm increments to maximum compression. The Young Modulus, E, was calculated from each trial using engineering stress. Data were analyzed using Mann-Whitney and t tests.
The Passage, Snake 6F, and Snake 7F stents had tensile strengths of 27±3, 5±0.1, and 73±26 kPa, respectively. Mann-Whitney tests show statistically significant difference between stents (P<0.05). Elastic modulus needed to cause extrinsic compression was highest for Snake 6F (145,842±14332 Pa) compared with that of Passage (124,999±3182 Pa) and Snake 7F (126,132±19316 Pa), (P<0.05).
The Snake 6F stent had the lowest tensile strength and was least resistant to extrinsic compression. The Snake 7F had the highest tensile strength and was most resistant to extrinsic compression. All three stents are more resistant to extrinsic compression than the Applied Silhouette or Cook Resonance, yet have lower tensile strengths.
外在输尿管压迫会挑战输尿管支架促进尿液引流和保护肾脏的能力。我们的目的是评估新型金属丝线圈输尿管支架的拉伸强度和径向压缩力性能。
从 Prosurg Inc 测试了三种支架设计，包括 Passage 7.0F、Snake 6.0F 和 Snake 7.0F，其直段覆盖有生物相容性聚合物管。使用 MTS Microbionix 测试系统和 Testworks II 软件、隔振台和 5-N 负载单元测量拉伸和压缩强度。将支架放置在液压夹具中，在单向拉伸下以 5mm/s 的速率拉伸 1 秒。以 0.1mm 的增量施加外在压缩，直至达到最大压缩。使用工程应力从每个试验计算杨氏模量，E。使用 Mann-Whitney 和 t 检验分析数据。
Passage、Snake 6F 和 Snake 7F 支架的拉伸强度分别为 27±3、5±0.1 和 73±26kPa。Mann-Whitney 检验表明支架之间存在统计学显著差异（P<0.05）。引起外在压缩所需的弹性模量对于 Snake 6F（145,842±14332 Pa）最高，与 Passage（124,999±3182 Pa）和 Snake 7F（126,132±19316 Pa）相比，（P<0.05）。
Snake 6F 支架的拉伸强度最低，对外在压迫的抵抗力最小。Snake 7F 的拉伸强度最高，对外在压迫的抵抗力最大。所有三种支架对外在压迫的抵抗力都强于 Applied Silhouette 或 Cook Resonance，但拉伸强度较低。
