Asymmetric RF Electrode Shaft for Side-Outlet Cannula Lesion Control
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Solution Overview
Problem
Current RF electrode systems for tissue ablation often result in symmetric heat lesions, limiting the ability to precisely control the size and location of the ablation area, especially when using straight electrodes with side-outlet cannulas, which can restrict the extension of the electrode shaft and affect the uniformity of tissue heating.
Innovation Solution
The use of RF electrodes with straight, stiff shafts that extend from a side opening in the cannula, allowing for asymmetric heat lesion formation by conducting RF current from both the cannula active tip and the electrode shaft, which remains straight over its entire length, including within and around the cannula side opening, to enhance the size and control of the ablation area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a straight electrode is used with a side-outlet cannula, then the electrode placement is simplified, but the electrode shaft extension is restricted and tissue heating uniformity is affected
Solution Approach 1:
The electrode shaft is configured to extend in multiple directions: primarily along the longitudinal axis of the cannula, and secondarily laterally through the side outlet. This multi-dimensional extension allows the electrode to overcome the restrictions of side-outlet cannula placement while maintaining ease of insertion, enabling both simplified placement and adequate shaft extension for effective tissue heating.
2Device complexity
If a straight electrode is used with a side-outlet cannula, then the electrode structure is simplified, but the ablation area control precision is reduced
Solution Approach 1:
The electrode shaft is designed with an asymmetric configuration where the distal portion extends laterally through the side outlet at an angle relative to the longitudinal axis. This asymmetric extension creates a controlled, non-uniform heating pattern that enables precise ablation area control while maintaining a relatively simple overall electrode structure without complex mechanical components.
3Volume of moving object
If the electrode shaft extends through the side opening, then the ablation volume is increased, but the heat lesion symmetry is reduced
Solution Approach 1:
The electrode shaft exhibits different geometric properties at different locations: the proximal portion maintains a straight configuration along the longitudinal axis for uniform heating, while the distal portion extends laterally through the side outlet to create asymmetric heating in the target tissue. This local variation in geometry enables increased ablation volume while controlling the symmetry characteristics in different spatial zones.
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 configuration enables the generation of larger, asymmetric RF heat lesions, improving the precision and effectiveness of tissue ablation by allowing the electrode shaft to consistently extend from the side opening, thereby increasing the treated volume and controlling the lesion's location relative to the cannula axis.
Implementation Method 1
heating of the target tissue by RF power dissipation of the RF signal output in the target tissue
Implementation Method 2
Temperature monitoring of the target tissue by a temperature sensor in the electrode can control the process
Data Source
AI summary
An RF electrode can have a straight shaft to generate an RF heat lesion that is asymmetric about the central axis of the cannula through which the RF electrode is introduced into bodily tissue.