Clinical sampling of tissue that is read by a pathologist is currently the gold standard for making a disease diagnosis, but the few minimally invasive techniques available for small duct biopsies have low sensitivity, increasing the likelihood of false negative diagnoses. We propose a novel biopsy device designed to accurately sample tissue in a biliary stricture under fluoroscopy or endoscopic guidance. The device consists of thin blades organized around the circumference of a cylinder that are deployed into a cutting annulus capable of comprehensively sampling tissue from a stricture. A parametric study of the device performance was done using finite element analysis; this includes the blade deployment under combined axial compression and torsion followed by an axial ‘cutting’ step. The clinical feasibility of the device is determined by considering maximum deployment forces, the radial expansion achieved and the cutting stiffness. We find practical parameters for the device operation to be an overall length of 10 mm and a diameter of 3.5 mm for a $50~\mu \text{m}$ blade thickness, which allow the device to be safely deployed with a force of 10N and achieve an expansion over 3x its original diameter. A model device was fabricated with these parameters and a $75~\mu \text{m}$ thickness out of a NiTi superalloy and tested to validate the performance. The device showed strong agreement with an equivalent numerical model, reaching a peak force within 2% of that predicted numerically and fully recovering after compression to 20% of its length. Clinical and Translational Impact Statement –This pre-clinical research conceptually demonstrates a novel expandable device to biopsy tissue in narrow strictures during an ERCP procedure. It can greatly improve diagnostic tissue yield compared to existing methods.

中文翻译：

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专为胆道设计的导管内组织取样装置

病理学家读取的组织临床样本目前是做出疾病诊断的金标准，但可用于小导管活检的少数微创技术灵敏度低，增加了假阴性诊断的可能性。我们提出了一种新型活检装置，旨在在透视或内窥镜引导下准确地对胆道狭窄中的组织进行取样。该装置由围绕圆柱体圆周组织的薄刀片组成，这些刀片被部署到能够从狭窄处全面取样组织的切割环中。使用有限元分析对器件性能进行了参数研究；这包括叶片在轴向压缩和扭转组合下展开，然后是轴向“切割”步骤。该装置的临床可行性是通过考虑最大展开力、实现的径向扩张和切割刚度来确定的。我们发现设备操作的实际参数是 10 毫米的总长度和 3.5 毫米的直径 $50~\mu \text{m}$刀片厚度，使设备能够以 10N 的力安全展开，并实现超过其原始直径 3 倍的膨胀。用这些参数和一个模型设备制造 $75~\mu \text{m}$NiTi 高温合金的厚度并经过测试以验证性能。该装置与等效数值模型表现出很强的一致性，达到了数值预测值的 2% 以内的峰值力，并且在压缩到其长度的 20% 后完全恢复。临床和转化影响陈述 – 这项临床前研究在概念上展示了一种新型可扩展装置，用于在 ERCP 手术过程中对狭窄狭窄处的组织进行活检。与现有方法相比，它可以大大提高诊断组织的产量。