Introduction

Colonoscopy is a commonly-performed procedure to diagnose pathology of the large intestine. Perforation of the colon is a rare but feared complication. It is currently unclear how much force is actually required to cause such injury nor how this is altered in certain diseases. Our aim was to analyze the forces required to perforate the colon in experiments using porcine tissues.

Methods

Using 3D printing technology, models of two commercially available colonoscope heads were printed under three configurations: straight (I), 90°- bent (L) and fully bent (U). Samples of porcine colon were assessed with the models and configurations under perpendicular and angular load application and these data compared to the maximum force typically exerted by experienced colonoscopists.

Results

The force required for perforation was significantly lower for the I compared to the L of the larger colonoscope head configuration under angular loading (14.1 vs. 46.5 N). Similar differences were found for linear stiffness when loaded (I vs. L small when loaded perpendicular: 0.8 vs. 2.4 N/mm, I vs. L large when loaded angled 0.7 vs. 2.1 N/mm). The mode and site of failure varied significantly between the scopes, with delamination of the mucosa/submucosa below the sample (96%) for the I, blunt mucosa/submucosa/muscularis failure adjacent to the loading site (77%) for the L, and failure of all colon layers lateral to the loading site (59%) for the U configuration, respectively. Perpendicular and angulated loading resulted in similar load-deformation values. Maximum forces typically exerted by colonoscopists averaged 13.9–27.9 N, depending on the colonoscope model and head configuration.

Discussion

The force required for colon perforation varies depending on the type mode of loading and is likely lower than the force an experienced colonoscopist would exert in daily practice. There is a real risk of perforation, especially when the end of the scope is advancing directly into the colonic wall. The given experimental setup allowed to obtain reliable data of the colon in a standardized scenario, forming the basis for further experiments.

中文翻译：

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在结肠镜检查中需要多少力才能穿透结肠？实验研究。

介绍

结肠镜检查是诊断大肠病理的常用方法。结肠穿孔是一种罕见但令人恐惧的并发症。目前尚不清楚，实际上需要多大的力才能造成这种伤害，或者在某些疾病中这种状况如何改变。我们的目的是分析在使用猪组织进行的实验中穿孔结肠所需的力。

方法

使用3D打印技术，以三种配置打印两个市售结肠镜检查头的模型：笔直（I），90°弯曲（L）和完全弯曲（U）。在垂直和角向载荷作用下，用模型和构型评估猪结肠样品，并将这些数据与经验丰富的结肠镜检查专家通常施加的最大力进行比较。

结果

与较大的结肠镜检查头配置的L在角向负载（14.1 vs. 46.5 N）下相比，I穿孔所需的力明显较低。加载时的线性刚度也发现了类似的差异（垂直加载时，I与L较小：垂直加载时为0.8与2.4 N / mm；加载角度为0.7与2.1 N / mm时，I与L较大）。失效的方式和部位在两个范围之间变化很大，I以下的粘膜/粘膜下层分层（I为96％），L邻近加载部位的钝性粘膜/粘膜下层/肌层衰竭（77％），对于U形结构，分别位于装载部位侧面的所有结肠层的破坏（59％）。垂直和成角度的载荷导致相似的载荷-变形值。通常由结肠镜检查专家施加的最大力为13.9–27.9 N，

讨论

结肠穿孔所需的力因负荷类型而异，可能比有经验的结肠镜医师在日常练习中所施加的力要低。确实存在穿孔的风险，尤其是当示波器的末端直接进入结肠壁时。给定的实验设置可以在标准化情况下获得可靠的结肠数据，从而为进一步的实验奠定了基础。