Multi-Edge Ablation Tip Geometry for Accurate Tumor Penetration
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Solution Overview
Problem
Penetrating smaller tumors or tough tissues is challenging due to their displacement by compliant surrounding tissues, making it difficult to ensure accurate placement of ablation antennas, and existing designs require high penetration forces.
Innovation Solution
Tissue penetrating device tips with multiple cutting edges and optimized geometries, such as concave faces and reduced dihedral angles, minimize tissue displacement and penetration force by combining cutting and stretching, allowing for precise tumor ablation with reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional tissue penetrating devices are used, then penetration force is high, but tissue displacement occurs and accurate placement becomes difficult
Solution Approach 1:
The cutting surface is divided into multiple discrete cutting edges (at least three, preferably four) arranged radially around the tip. Each cutting edge independently engages the tissue, distributing the penetration force across multiple contact points rather than concentrating it at a single point, thereby reducing overall tissue displacement while maintaining penetration effectiveness
Solution Approach 2:
The device incorporates a curved cutting surface with a radius of curvature between 0.5mm and 2mm, optimized to match typical tumor sizes. This curvature allows the cutting edges to engage tissue at optimal angles throughout the penetration arc, improving placement accuracy by ensuring consistent contact geometry while reducing the peak forces required compared to linear cutting edges
2Length of moving object
If smaller device tips are used for small tumors, then minimally invasive capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
Multiple cutting edges are integrated into a single monolithic component formed from one piece of material. This unified structure eliminates the need for separate manufacturing and assembly of individual cutting edges, reducing cumulative tolerances and simplifying quality control while maintaining the small tip dimensions required for minimally invasive access
Solution Approach 2:
The cutting edges are formed with controlled surface roughness parameters (Ra 0.2-0.8 micrometers) through precision machining or laser processing. This optimization of surface parameters ensures adequate tissue engagement while accommodating realistic manufacturing tolerances, avoiding overly stringent precision requirements that would complicate production of small tips
3Measurement precision
If multiple cutting edges are added to reduce tissue displacement, then placement accuracy improves, but device complexity increases
Solution Approach 1:
The curved cutting surface with multiple radial cutting edges serves multiple functions simultaneously: it provides stable tissue engagement during penetration, self-aligns the device with the target tissue through geometric constraints, and maintains consistent cutting geometry throughout the penetration arc. This multi-functionality is achieved within a simple monolithic structure, avoiding the need for complex mechanisms
Solution Approach 2:
The cutting edges are positioned at specific radial locations and angles optimized for their local tissue engagement requirements. Each cutting edge's geometry and orientation is tailored to its specific position on the curved surface, maximizing local cutting efficiency while the overall simple structure maintains low device complexity
Data Source
AI summary
An ablation instrument comprises a cable, a conductive antenna body coupled to the cable and configured to deliver ablative energy to tissue, and a tip having a cross-sectional diameter of less than 5 mm. The tip comprises a blade configured to cut a slit in the tissue. The blade comprises a plurality of cutting edges, and each cutting edge of the plurality of cutting edges has a width between 30% and 50% of the cross-sectional diameter of the tip.