Collaborative Research: Understanding Dynamic Behaviors of Tissue Welding for High Quality Electrosurgical Tissue Joints

组织焊接，也被称为电外科组织连接，是外科手术中用来封闭血管以控制出血的一种过程。它使用电阻加热和机械夹持相结合的方式来提高组织温度和变性胶原蛋白，从而使分离的组织可以重新连接。组织焊接变得越来越普遍，因为越来越多的人使用微创手术程序，只需做几个小切口就可以接触到手术部位。在这些情况下，由于可获得性有限，很难使用传统的手工缝合技术来封闭伤口。美国每年有超过150万例涉及组织焊接过程的外科手术。2011年，美国电外科设备的总体市场规模超过10亿美元，并以每年5%-6%的速度增长。尽管组织焊接很重要，但由于缺乏对组织焊接过程的良好理解和适当的质量控制，组织焊接接头的质量往往不一致。关节损坏会导致严重出血，延长手术时间，并影响手术效果。这项研究将导致更一致和可靠的组织关节，从而提高医疗保健的安全性和质量。它还将促进用于组织焊接的电外科工具的进步，并增加美国医疗器械制造的竞争力。研究小组将研究组织焊接过程中组织热阻抗和电阻抗的动态行为，并将这些行为与接头强度相关联。组织的热阻抗和电阻抗将在不同的热剂量水平上进行实验测定。研究结果将被用于建立多物理有限元模型，以根据电能输入来预测接头部位的时空温度分布。探讨夹紧力对电刀与组织接触面积的影响。使用不同水平的热剂量和机械夹紧力对一系列组织接头进行试验，并对这些接头进行强度测试，建立焊接质量预测模型。从这项关于生物材料对热反应的研究中获得的基本理解将在其他外科手术过程中得到许多应用，如激光和超声肿瘤消融术。

Tissue welding, also known as electrosurgical joining of tissues, is a process used in surgery to seal blood vessels in order to control bleeding. It uses a combination of electro-resistive heating and mechanical clamping to elevate tissue temperature and denature collagen, such that separate tissue can be reconnected. Tissue welding is becoming more prevalent because of the increasing use of minimally invasive surgical procedures, where only a few small incisions are made to access the surgical site. In these cases, it is difficult to use the traditional hand suturing technique to seal wounds because of limited accessibility. There are more than 1.5 million surgical procedures done in US annually that involve the tissue welding process. The overall market size for electrosurgical devices is more than 1 billion dollars in US in 2011 and is increasing by 5-6 percent each year. Despite its importance, the quality of tissue welding joints is often inconsistent due to the lack of good understanding and proper quality control of the tissue welding process. Failed joints can cause severe bleeding, prolonged operative time, and impaired surgical outcomes. This research will lead to more consistent and reliable tissue joints, thus improved healthcare safety and quality. It will also lead to the advancement of electrosurgical tools for tissue welding, and increase the competitiveness of US medical device manufacturing. The research team will study the dynamic behavior of tissue's thermal and electrical impedances during the tissue welding process and to correlate these behaviors to the joint strength. The tissue thermal and electrical impedances will be experimentally determined at different levels of thermal dose. The results will be used to develop a multi-physics finite element model to predict spatial and temporal temperature distribution of the joint site from the electrical energy input. The effect of clamping force on the contact area between the electrosurgical tool and tissue will be explored. A series of tissue joints using various levels of thermal dose and mechanical clamping force will be conducted and the strength of these joints tested to establish a weld quality prediction model. The fundamental understanding obtained from this research on biological material responses to heat will find many applications in other surgical processes, such as laser and ultrasonic tumor ablation.