Dissertation
Minimization of Thermal Spread During the Electrosurgical Tissue Joining Process
Doctor of Philosophy (PhD), Washington State University
01/2019
Handle:
https://hdl.handle.net/2376/117884
Abstract
Electrosurgical vessel sealing is commonly performed in the surgical process to maintain hemostasis. The process involves mechanical clamping and joule heating to achieve the good quality of vessel sealing. However, many factors have been noticed and reported such as compressive ratio, elevated temperature, and size of the tissue known to influence the quality of vessel sealing. The goal of the research is to minimize the thermal damage with a high joining strength.
In order to minimize the thermal damage during the joining process, a hybrid method combining experimental measurement with inverse heat transfer analysis was proposed to determine the thermal conductivity of thin tissue sample with varying thermal dose. A regression model was created to describe thermal conductivity as a function of thermal dose. This regression model was further optimized using an iterative approach to correlate thermal conductivity to a more accurately calculated thermal dose. The finite element model implemented with this regression model can predict temperature more accurately, especially for tissues in between the electrodes.
The progression of the tissue joining process was characterized by real-time impedance measurement. This result was cross compared to the finite element model prediction and a better understanding of the tissue joining process was achieved. A new index, strength-energy the coefficient, was introduced to evaluate the energy efficiency in converting electrical energy into joining strength. It was found that a higher compression level yields a higher strength-energy coefficient and a high-quality joint can be achieved while consuming less energy when using a higher compression level.
A new concept for tissue joining – sequential compression which uses a pair of small electrodes to achieve a high compression level with a smaller compressive force, was proposed and validated. This concept resulted in the strength-energy coefficient that is three times higher than the traditional method and has the potential to reduce thermal damages during the process.
Metrics
27 File views/ downloads
78 Record Views
Details
- Title
- Minimization of Thermal Spread During the Electrosurgical Tissue Joining Process
- Creators
- Che-Hao Yang
- Contributors
- Kuen-Ren Chen (Advisor)Arda Gozen (Committee Member)Jin Liu (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 117
- Identifiers
- 99900581505101842
- Language
- English
- Resource Type
- Dissertation