Variable Cross-Section Snare for Tissue Resection
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Solution Overview
Problem
Conventional snares used in medical procedures for tissue resection are stiff, leading to deflection away from the tissue wall, inadequate traction, and inefficient cutting, resulting in suboptimal resection and potential tissue damage.
Innovation Solution
A medical device with a snare member having a distal portion with a smaller cross-sectional area than the proximal portion, featuring a transition portion and radially extending traction members, enhancing flexibility and traction for improved conformance to the tissue plane during resection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional snaire with uniform cross-section is used, then the snare structure is simple, but the snare becomes stiff and deflects away from the tissue plane during resection
Solution Approach 1:
The snare member is designed with non-uniform cross-sectional area along its length. The distal portion has a smaller cross-sectional area than the proximal portion, creating local variation in flexibility. This allows the distal portion to be more flexible and conform to the tissue plane while the proximal portion maintains structural integrity.
Solution Approach 2:
The cross-sectional area parameter of the snare member is varied along its length. By reducing the cross-sectional area at the distal portion, the flexibility parameter is increased locally, enabling better conformance to the tissue plane during resection procedures.
2Force
If downward force is applied to improve snare traction, then traction on target tissue increases, but the distal portion deflects away from the tissue wall
Solution Approach 1:
The distal portion of the snare member is designed with smaller cross-sectional area to be more flexible, allowing it to maintain contact with the tissue wall even when downward force is applied. This local flexibility prevents deflection away from the tissue wall while still enabling adequate traction.
3Ease of manufacture
If a uniform cross-section snare loop is used, then the snare is easier to manufacture, but the current density delivered to target tissue is reduced
Solution Approach 1:
The snare member has varying cross-sectional area along its length, with the distal portion having smaller area. This creates local concentration of electrical current at the distal portion where it contacts the tissue, increasing current density for more effective cutting and resection.
4Strength
If a thick uniform cross-section snare loop is used, then the snare has adequate structural strength, but greater force is required to extend and retract the snare loop
Solution Approach 1:
The proximal portion of the snare member maintains larger cross-sectional area for structural strength, while the distal portion has smaller cross-sectional area for flexibility and ease of actuation. This local differentiation reduces the force required to extend and retract the snare loop while maintaining adequate structural integrity.
5Stability of the object's composition
If a stiff snare loop is used, then the snare maintains its shape, but the risk of unintended tissue trauma and perforation increases
Solution Approach 1:
The distal portion of the snare member is designed with smaller cross-sectional area to be more flexible, reducing the risk of tissue trauma and perforation. The proximal portion maintains larger cross-sectional area for shape maintenance. This local differentiation allows the snare to maintain overall shape while being gentle on the tissue at the contact point.
Data Source
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Figure 7A~8B
AI summary
In accordance with an aspect of the present disclosure, the medical device includes a snare member having a proximal portion and a distal portion. The medical device also includes an operating member extending proximally of the snare member. The operating is enabled to extend and retract the snare member from a sheath. The snare member includes a transition portion extending between the proximal portion and the distal portion. The transition portion connects the proximal portion to the distal portion. The distal portion has a different cross-sectional area than the proximal section of the snare member.