Investigation of colorectal stapled anastomosis by means of experimental and numerical approaches

结肠疾病是消化道的下部，是非常常见的疾病，根据美国胃肠和内窥镜外科医生协会(SAGS)的数据，美国每年要进行60多万例外科手术来治疗这些疾病。结直肠手术是为了修复由癌症、憩室炎、肠息肉和炎症性肠炎等疾病引起的结肠、直肠和肛门的损伤。请注意，结直肠癌是全球男性第四大常见癌症和女性第三大常见癌症。在切除结肠的过程中，病变的肠段被切除，两段健康的结肠被重新连接，这被称为结肠吻合术。传统上，吻合术受到外科医生选择缝合或缝合的影响。尽管后一种方法比前一种方法更规范、更快速、更容易，具有良好的血液控制、减少组织操作、组织适应均匀等优点，但仍存在渗漏、狭窄和术后出血等并发症。吻合口漏是最严重的并发症，也是发病率和死亡率的重要原因。据报道，术后漏和死亡率分别高达16%和3.2%。科学文献表明，技术错误可能起重要作用，潜在地增加术后并发症的风险。吻合线的完整性依赖于足够的组织压迫，是形成稳定吻合口的主要因素。了解组织如何与订书机和订书机相互作用是改善患者预后的关键。本研究的目的是通过实验测量和有限元模拟的方法研究结肠端端吻合术的整体力学性能，以期初步填补吻合术中存在的知识空白。这将有助于制造商开发最优的吻合器配置，帮助外科医生正确操作这些器械，并随后改善患者的预后。为此，将进行生物力学测试，以确定结肠组织的特征。基于目前在结直肠手术中常用的两种圆形吻合器的计算模型将被开发和模拟。将通过参数研究来研究初始组织厚度和特性、缝合高度、缝合行数和每行缝合数量的影响。将确定用于微创手术的圆形吻合器的最佳设计。最合适的缝合高度作为组织厚度的函数也将被评估和讨论以供临床决策。

Diseases of the colon, the lower part of the digestive tract, are very common and according to the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) more than 600,000 surgical procedures are performed in the United States every year to treat them. Colorectal surgery is performed to repair damage to the colon, rectum, and anus, caused by diseases such as cancer, diverticulitis, intestinal polyps and inflammatory bowel. Note that colorectal cancer is the fourth most common cancer in men and the third most common cancer in women worldwide. During a colon resection, the diseased part of the bowel is removed and the two healthy sections of the colon are reattached which is called a colorectal anastomosis. Anastomotic technique has traditionally been influenced by surgeons’ preference to use either suturing or stapling. Although the later technique is more standardized, quicker and easier than the former one with benefits such as excellent blood control, reduced tissue manipulation and uniformity of tissue adaptation, there remain complications like leakage, stricture and postoperative bleeding. Anastomotic leak is the most serious complication and is a significant cause of morbidity and mortality. Postoperative rates of leak and mortality up to 16% and 3.2% have been reported. Scientific literature shows that technical errors can play a significant role, potentially increasing the risk of postoperative complications.The integrity of the staple lines, which depends on adequate tissue compression, is the primary factor in making a stable anastomosis. Understanding how tissues interact with stapler and staples is the key to improving patient outcomes. The purpose of this research is to study the overall mechanical performance of the end-to-end stapled colorectal anastomosis by means of experimental measurement and finite element simulation in order to initially fill the existing knowledge gap in anastomotic technique. This would help manufacturers to develop optimal stapler configurations and surgeons to handle these instruments correctly, and subsequently to improve patient outcomes. To do this, biomechanical tests will be done to characterize colon tissues. Computational models based on two current circular staplers that are frequently used in colorectal surgery will be developed and simulated. The effect of initial tissue thickness and properties, staple height, number of staple rows and number of staples per row will be investigated through a parametric study. Optimal design of circular stapler for use in minimally invasive surgery will be ascertained. Best-fitted staple heights as a function of the tissue thickness will also be evaluated and discussed for clinical decision making.