A Novel Parameter for Predicting Arterial Fusion and Cutting in Finite Element Models

Abstract

Current efforts to evaluate the performance of laparoscopic arterial fusion devices are limited to costly, time consuming, empirical studies. Thus, a finite element (FE) model, with the ability to predict device performance would improve device design and reduce development time and costs. This study introduces a model of the heat transfer through an artery during electrosurgical procedures that accounts for changes in thermal material properties due to water loss and temperature. Experiments then were conducted by applying a known heat and pressure to carefully sectioned pieces of porcine splenic arteries and measuring cut completeness. From this data, equations were developed to predict at which temperature and pressure arterial tissue is cut. These results were then incorporated into a fully coupled thermomechanical FE model with the ability to predict whole artery cutting. An additional experiment, performed to examine the accuracy of the model, showed that the model predicted complete artery cut results correctly in 28 of 32 tests. The predictive ability of this FE model opens a gateway to more advanced electrosurgical fusion devices and modeling techniques of electrosurgical procedures by allowing for faster, cheaper and more comprehensive device design.

Thermal Resistance Anastomosis Device for the Percutaneous Creation of Arteriovenous Fistulae for Hemodialysis

“…Tissue fusion occurs when collagen I is denatured by tissue temperatures greater than 1401C while subjected to pressures of 30-330 psi causing crosslinking collagen fibrils in adjacent tissues (20,21). Cutting occurs with additional application of heat and pressure (22). Tissue fusion is widely used in laparoscopic surgery to ligate and divide vessels by using various types of energy to provide immediate and durable sealing of vessels (23).…”

Overview on the Evolution of Laser Welding of Vascular and Nervous Tissues

“…According to these authors, the single-spot method may be more beneficial when applied through multiple laser pulses in the surgical area, enabling tissue to cool down between pulses, and therefore, decreasing the thermal damage. Research has also been conducted to predict tissue damage and the corresponding effect by a finite element method, which may provide useful pre-operative information for the laser-welding procedure [74].…”

A Small Deformation Thermoporomechanics Finite Element Model and Its Application to Arterial Tissue Fusion

“…Transactions of the ASME 2.9 Experimental Measurements. The experimental results used to evaluate the performance of the FE model were taken from data published within the literature [2,26,27] as well as supplemental experiments conducted by the first and third authors following the same procedures outlined in these papers. The temperature measurements were taken within the lumen of a compressed artery using an array of thermocouples.…”

“…To obtain the Young's Modulus, E, used in the finite element simulations, a best fit analysis was conducted using the engineering stress and strain recorded in the tissue after mechanically loading the tissue, but before heating. A more detailed explanation of the MTS attachments and experimental setup can be found in the work by Fankell et al [2].…”

“…Biological tissue undergoes thermal loading in several manners ranging from surgical devices that heat or cool biological tissue to cauterize or ablate it [1][2][3][4], to natural causes such as hyperthermia or frostbite [5]. Scientists and physicians seek to understand these processes and their impact on tissue mechanics to create novel, safer, and more effective medical devices and procedures.…”