Flared Electrode Ablation Probe for Asymmetric Lesions
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Solution Overview
Problem
Existing RF ablation devices face challenges with electrodes having low column strength, which leads to buckling issues, and they often create symmetrical lesions, failing to accommodate customized or voluminous lesion shapes effectively.
Innovation Solution
The design incorporates electrodes with curvilinear or flared profiles that change configuration when deployed, featuring a distal portion with an angle of 120° or less from the cannula axis, and a distal tip spaced at least 20% of the electrode's length from the cannula exit, enhancing column strength and allowing for asymmetric lesion creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If longer wires are used to create longer tines to span across larger tissue areas, then the treatment coverage is improved, but the column strength of the tines decreases causing them to buckle easily
Solution Approach 1:
The electrode is divided into multiple segments or sections along its length, with each section having different geometric characteristics. This segmentation allows the electrode to maintain structural integrity while extending over longer distances, preventing buckling by creating multiple shorter, stiffer segments rather than one long flexible element
Solution Approach 2:
The electrode incorporates curved or flared geometric profiles rather than straight linear designs. The curvature and flaring increase the moment of inertia and column strength of the electrode, allowing it to span larger tissue volumes without buckling while maintaining the necessary mechanical rigidity
2Strength
If the cross-sectional size of the electrode is increased to improve column strength, then the buckling resistance is improved, but the overall size of the ablation probe increases making it less desirable
Solution Approach 1:
Instead of increasing the cross-sectional dimensions of the electrode (which would increase probe size), the design utilizes the longitudinal dimension by creating flared profiles and varying the electrode geometry along its length. This dimensional approach increases column strength without increasing the probe's overall size
Solution Approach 2:
The flared and curved electrode profiles increase the moment of inertia and structural rigidity along the electrode's length, providing enhanced column strength without requiring a larger cross-sectional area, thus avoiding an increase in overall probe size
3Shape
If electrodes with sharp 90° bends and flat profiles are used to create flat lesions, then the lesion shape control is improved, but the electrodes undergo excessive bending stress when housed within the cannula
Solution Approach 1:
The design replaces sharp 90° bends with gradual curved transitions and uses flared profiles that distribute bending stresses more evenly along the electrode structure. This curvature approach maintains precise lesion shape control while significantly reducing peak bending stresses during deployment from the cannula
Solution Approach 2:
The electrode geometry parameters are optimized to create flared profiles with specific angle ranges (120° or less from the cannula axis) that balance lesion shape control with stress reduction. By changing the geometric parameters from sharp angles to controlled curves, both lesion precision and structural integrity are achieved
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 improves the mechanical stability of electrodes, reduces buckling, and enables the creation of customized, asymmetric lesions with improved column strength, addressing the limitations of existing devices.
Implementation Method 1
RFA treatment involves destroying undesirable cells by generating heat through agitation caused by the application of alternating electrical current (radio frequency energy) through the tissue.
Implementation Method 2
The buckling of the electrodes may occur within the cannula as the electrodes are being advanced within the cannula. In other cases, the buckling of the electrodes may occur outside the cannula as the electrodes penetrate through tissue
Data Source
AI summary
An ablation device includes a cannula having a proximal end, a distal end, and a lumen extending between the proximal and the distal ends, and a first array of electrodes at least partially disposed within the lumen, the first array of electrodes slidable relative to the cannula, each of the electrodes having a first configuration when inside the lumen, and a second configuration when unconfined outside the lumen, wherein one of the electrodes has a flared deployed profile.