Internally Cooled Bipolar RF Ablation Electrodes
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Solution Overview
Problem
Existing electrosurgical devices face challenges in achieving deep tissue penetration while minimizing surface heating during RF ablation, leading to inefficient creation of transmural lines of ablation in cardiac tissue.
Innovation Solution
The development of a bi-polar RF ablation device with four electrically conductive ablation members, each having internal fluid passageways that are electrically isolated and in fluid communication with each other, along with a vacuum port for securing the device to the tissue, and a fluid reservoir/pump assembly for circulating cooling fluid to prevent overheating and enhance electrode-tissue contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If RF energy is applied to tissue with moisture conduction, then surface tissue heating occurs, but deep tissue penetration is limited
Solution Approach 1:
The patent applies preliminary cooling to the tissue surface before RF ablation to prevent excessive surface heating. The cooling catheter is positioned adjacent to the ablation electrode and delivers cold fluid to pre-cool the tissue, creating a thermal barrier that prevents RF-induced surface heating while allowing deep penetration of RF energy into the tissue.
Solution Approach 2:
The patent introduces a cooling catheter as an intermediary element between the RF electrode and the tissue. This cooling catheter acts as a thermal mediator that conducts heat away from the tissue surface, enabling the RF energy to penetrate deeper without causing excessive surface temperature rise. The cooling catheter serves as a thermal sink that protects the surface while allowing energy transmission to deeper tissues.
2Temperature
If cooling fluid is introduced to reduce surface heating, then surface temperature decreases, but device complexity increases
Solution Approach 1:
The patent divides the ablation device into separate functional components: an ablation electrode for RF energy delivery and a separate cooling catheter for thermal management. This segmentation allows each component to be optimized independently - the electrode for effective ablation and the cooling catheter for efficient heat dissipation - while reducing overall device complexity compared to integrating both functions into a single complex structure.
Solution Approach 2:
The cooling catheter serves as a simple intermediary element that interfaces with the tissue to provide cooling. Rather than complicating the electrode structure, the patent uses a separate cooling catheter positioned adjacent to the tissue as a straightforward thermal management solution, reducing device complexity while achieving effective surface cooling.
3Reliability
If electrodes are positioned to maximize contact, then electrical conductivity improves, but surface heating increases
Solution Approach 1:
The patent uses preliminary cooling to counteract the surface heating that would result from good electrical contact. By pre-cooling the tissue surface with the cooling catheter before and during RF ablation, the system can maintain excellent electrode-tissue contact for reliable energy delivery while preventing excessive surface temperature rise through the thermal barrier created by the cooling fluid.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces surface tissue heating, allowing for deeper penetration of RF energy and more effective creation of transmural ablation lines with reduced surface damage, improving the efficiency and consistency of the ablation process.
Implementation Method 1
each having internal fluid passageways that are electrically isolated from each other, with the fluid passageways of each of the four ablation members being in fluid communication with each other
Implementation Method 2
a vacuum port for securing the device to the tissue
Implementation Method 3
bi-polar RF ablation device with four electrically conductive ablation members
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An electrosurgical end effector for ablating tissue is provided that comprises at least one elecfrically-conductive ablation member adapted to be connected to a source of RF energy, with the ablation member having a tissue engaging surface and defining an internal fluid passageway. Preferably, the end effector includes two electrically conductive ablation members that are electrically isolated from one another and have their fluid passageways in fluid communication. Alternatively, the end effector may comprise four electrically conductive ablation members arranged as two pairs of ablation members, all of the ablation members having internal fluid passageways that are electrically isolated from each other, with the fluid passageways of each of the four ablation members being in fluid communication with each other.'