Characterization of the Electrosurgical Tissue Joining Process Using Dynamic Impedance and Energy Efficiency

Abstract

Electrosurgical tissue joining is an effective way to create hemostasis, especially in surgical procedures performed in the minimally invasive manner. The quality of tissue joints and potential thermal damages to the surroundings are the two main concerns when using electrosurgical tissue joining tools. A more robust method for quality control is still needed. The goal of this study is to characterize the joining process using dynamic impedance and energy efficiency. Three joining times (4, 6, and 8 s) and three compression levels (80%, 90%, and 95%) were used to join porcine arterial tissues while the process parameters including voltage, current, and impedance were monitored. Tensile tests were performed to evaluate the quality of tissue joints. A new index, the strength-energy coefficient (mmHg/J), which is defined as the tensile strength divided by the consumed energy, is introduced to evaluate the energy efficiency of the joining process. Strength-energy coefficient offers a new way to estimate the required joining time to achieve sufficient joining strength while minimizing the energy consumption to reduce thermal damages. The 95% compression level has the highest strength-energy coefficient for 4- and 6-s joining times. This indicates that the 95% compression level has higher energy efficiency and can form a good tissue joint with less energy and time in comparison with those required by a lower compression level. The progression of the tissue joining process was characterized by the real-time impedance measurement, which can be used as a tool for quality control.