Variable Thickness Electrosurgical Snare for Tissue Resection
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Solution Overview
Problem
Existing electrosurgical snares with uninsulated distal loops of constant diameter struggle to achieve a balance between cutting and coagulation during tissue resection, often resulting in excessive coagulation or bleeding due to inconsistent current density, which complicates tissue removal and regeneration.
Innovation Solution
An electrosurgical snare with a distal loop featuring uninsulated portions of varying thickness, where a thinner portion is used for cutting and a thicker portion for coagulation, allowing for controlled current distribution and retraction to optimize tissue resection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant diameter uninsulated distal loop is used, then the RF current is distributed evenly over the entire length of the exposed wire, but the current density is too low to effectively cut the tissue and may cause excessive coagulation
Solution Approach 1:
The distal loop is designed with variable thickness: a thinner portion for cutting and a thicker portion for coagulation. This local differentiation allows the thinner section to concentrate current density for effective cutting while the thicker section provides lower current density for controlled coagulation, resolving the contradiction between cutting effectiveness and excessive coagulation.
Solution Approach 2:
The distal loop is segmented into functionally distinct regions based on thickness variations. The thinner uninsulated portion serves as a cutting element while the thicker uninsulated portion serves as a coagulation element, allowing independent optimization of each function within a single continuous loop structure.
2Productivity
If power settings are increased to improve cutting, then cutting effectiveness improves, but circumferential coagulation increases and may cause excessive bleeding
Solution Approach 1:
By varying the thickness of the distal loop, the patent creates localized zones with different current densities. The thinner portion delivers high current density for rapid cutting without requiring high overall power settings, while the thicker portion delivers lower current density for controlled coagulation, preventing excessive bleeding even during high-power operation.
3Object-generated harmful factors
If a thicker distal loop is used, then coagulation is improved, but current density is reduced and cutting effectiveness decreases
Solution Approach 1:
The variable thickness design allows the distal loop to have a thicker portion for optimal coagulation control and a thinner portion for optimal cutting capability. Each section is locally optimized for its specific function, resolving the contradiction between coagulation control and cutting effectiveness that would exist in a uniform thickness design.
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 design enables precise cutting and coagulation, reducing bleeding and improving tissue sample quality while facilitating better histopathological evaluation by varying current density across the loop, thus enhancing the resection process.
Implementation Method 1
RF current is also applied to the tissue, which cuts the tissue
Implementation Method 2
the current density may be the same) over the portions of the distal loop in contact with the tissue
Implementation Method 3
the RF current may coagulate the tissue
Implementation Method 4
current density over the portions of the distal loop in contact with the tissue may be correspondingly too low
Data Source
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AI summary
An electrosurgical snare may include a conductive distal loop that includes an uninsulated thinner portion and an uninsulated thicker portion. Respective current densities over the outer surfaces of the thinner and thicker portions may cause the uninsulated thinner portion to immediately begin cutting tissue, while the uninsulated thicker portion may initially begin coagulating the tissue.