RF Electrode Cannula Sidewall Ejection for Ablation and Fluid Flow
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Solution Overview
Problem
Existing cannula and electrode assemblies for tissue ablation fail to efficiently control the volume of ablation and allow fluid flow while preventing the electrode from extending beyond the distal end of the cannula.
Innovation Solution
A cannula design featuring a sidewall opening and a cannula tip with a ramp configuration that ejects the electrode through the sidewall, allowing fluid flow and controlling electrode position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electrode extends out of the distal end of the cannula, then the ablation current flows through a larger volume of tissue, but the electrode cannot be properly positioned or controlled
Solution Approach 1:
The electrode is directed laterally through a sidewall opening rather than extending axially through the distal end of the cannula. This dimensional change allows the electrode to emerge perpendicular to the cannula axis, enabling both adequate ablation volume and precise position control through the side-opening mechanism.
2Manufacturing precision
If the cannula tip is designed to prevent electrode protrusion, then electrode position control is improved, but fluid flow through the cannula tip is blocked
Solution Approach 1:
The cannula tip is divided into functionally distinct segments: a proximal tip portion with a ramp structure for electrode ejection, and a distal tip portion with an opening for fluid flow. This segmentation allows the electrode and fluid to be directed through separate pathways, preventing electrode protrusion while maintaining fluid flow capability.
3Ease of operation
If a sidewall opening is provided in the cannula, then the electrode can be ejected laterally for better position control, but the structural integrity of the cannula is compromised
Solution Approach 1:
The sidewall opening is provided only in the proximal portion of the cannula, where it is needed for electrode ejection, while the distal portion of the cannula wall remains intact to maintain structural integrity. The localized opening minimizes weakening of the overall cannula structure while enabling the required functional capability.
Data Source
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AI summary
Described herein are cannulas that comprise a cannula tube and a cannula tip. The cannula tube comprises a proximal end, a distal end, a cannula tube lumen, a sidewall, and a sidewall opening extending through the sidewall, the sidewall opening a proximal end and distal end. The cannula tip is secured to the distal end of the cannula tube and comprises a proximal tip portion that is inserted into the cannula tube lumen and a distal tip portion that extends beyond the distal end of the cannula tube. The cannula tip is configured to allow fluid to flow therethrough and is configured to eject a distal tip of an elongated device through the sidewall opening of the cannula tube as the elongated device is inserted through the cannula tube from the proximal end of the cannula tube.