Fahmy Youssef, Trabia Mohamed B, Ward Brian, Gallup Lucas, Froehlich Mary
Department of Mechanical Engineering, Howard R. Hughes College of Engineering, University of Nevada, Las Vegas, NV 89154, USA.
Department of Surgery, Kirk Kerkorian School of Medicine, University of Nevada, Las Vegas, NV 89154, USA.
Bioengineering (Basel). 2024 Jan 8;11(1):64. doi: 10.3390/bioengineering11010064.
Many colonic surgeries include colorectal anastomoses whose leaks may be life-threatening, affecting thousands of patients annually. Various studies propose that mechanical interaction between the staples and neighboring tissues may play an important role in anastomotic leakage. Therefore, understanding the mechanical behavior of colorectal tissue is essential to characterizing the reasons for this type of failure. So far, experimental data characterizing the mechanical properties of colorectal tissue have been few and inconsistent, which has significantly limited understanding their behavior. This research proposes an approach to developing an anisotropic hyperelastic material model for colorectal tissues based on uniaxial testing of freshly harvested porcine specimens, which were collected from several age- and weight-matched pigs. The specimens were extracted from the same colon tract of each pig along their circumferential and longitudinal orientations. We propose a constitutive model combining Yeoh isotropic hyperelastic material with fibers oriented in two directions to account for the hyperelastic and anisotropic nature of colorectal tissues. Experimental data were used to accurately determine the model's coefficients (circumferential, R = 0.9968; longitudinal, R = 0.9675). The results show that the proposed model can be incorporated into a finite element model that can simulate procedures such as colorectal anastomoses reliably.
许多结肠手术都包括结直肠吻合术，其吻合口漏可能危及生命，每年影响数千名患者。各种研究表明，吻合钉与相邻组织之间的机械相互作用可能在吻合口漏中起重要作用。因此，了解结直肠组织的力学行为对于确定此类失败的原因至关重要。到目前为止，表征结直肠组织力学特性的实验数据很少且不一致，这严重限制了对其行为的理解。本研究提出了一种基于对新鲜采集的猪标本进行单轴测试来开发结直肠组织各向异性超弹性材料模型的方法，这些标本取自几只年龄和体重匹配的猪。标本从每头猪的同一结肠段沿其圆周和纵向方向提取。我们提出了一个本构模型，将Yeoh各向同性超弹性材料与两个方向上取向的纤维相结合，以考虑结直肠组织的超弹性和各向异性特性。实验数据用于准确确定模型的系数（圆周方向，R = 0.9968；纵向方向，R = 0.9675）。结果表明，所提出的模型可以纳入有限元模型，该模型能够可靠地模拟结直肠吻合术等手术过程。
