Tissue Excision Snare Wire Segmentation for Complete Constriction
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Solution Overview
Problem
Existing tissue excision instruments, such as snares, face challenges in effectively constraining and removing target tissues like polyps from the digestive tract due to limitations in loop size adjustment and distribution, leading to incomplete constriction and increased pressure on the sheath.
Innovation Solution
A tissue excision instrument featuring a snare wire with a first and second wire portion and a curved portion, coupled to a manipulation wire, which adjusts its protrusion from a sheath using a holder with a through-hole to ensure complete constriction of the target tissue, reducing the risk of tissue damage and improving excision efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional snare loop is used, then the snare loop can protrude and retreat with manipulation wire movement, but the loop size adjustment is limited and distribution is uneven leading to incomplete constriction
Solution Approach 1:
The snare wire is divided into multiple independent wire portions (first wire portion, second wire portion, third wire portion) that can be manipulated separately. Each wire portion can be advanced or retracted independently through the holder's through-hole, allowing differential control of the loop's different sections to achieve complete and uniform constriction of the target tissue.
Solution Approach 2:
The snare wire is designed to be movable relative to the holder through the through-hole, enabling dynamic adjustment of the wire portions' positions. This allows the loop to adapt its configuration and protrusion amount based on the target tissue's characteristics, improving both adjustability and constriction reliability.
2Force
If the snare loop protrudes from the sheath, then the loop can constrict target tissue, but pressure on the sheath increases leading to tissue damage risk
Solution Approach 1:
The wire portions are extracted from the sheath and holder structure, allowing them to be positioned independently. This enables the constricting force to be applied directly to the target tissue by the wire portions themselves, rather than through the sheath, thereby reducing pressure transmission to the sheath and minimizing the risk of tissue damage during the constriction process.
Solution Approach 2:
The holder acts as an intermediary structure that guides and controls the wire portions while isolating them from direct contact with the sheath. The through-hole in the holder allows the wire portions to pass through and apply force to the target tissue without transmitting excessive pressure to the sheath, serving as a mechanical mediator that decouples the constricting force from the sheath structure.
3Ease of manufacture
If a single elastic wire is bent back to form the snare loop, then the loop can be formed simply, but the distribution of wire portions is insufficient for complete constriction
Solution Approach 1:
Instead of using a single bent wire, the snare is constructed from multiple separate wire portions (first, second, and third wire portions) that can be independently formed and positioned. This segmentation allows each wire portion to be optimized for its specific function in the constriction process, improving overall constriction completeness while maintaining manufacturing simplicity through modular assembly.
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
The instrument achieves effective constriction and removal of target tissues with reduced pressure on the sheath, preventing tissue damage and enhancing the precision and efficiency of the excision process.
Implementation Method 1
The snare loop is formed by bending back a single elastic wire at a distal end thereof. The snare loop can protrude or retreat at a distal end of the sheath when the manipulation wire is advanced or retracted in the axial direction.
Data Source
AI summary
A tissue excision instrument that includes a sheath having a lumen, a manipulation member movably disposed inside the lumen, a snare wire coupled to a distal end of the manipulation member, and a holder provided at a distal portion of the sheath and configured to have a through-hole. The snare wire includes a first wire portion that has a first proximal portion including one end and a first distal portion, a second wire portion that has a second proximal portion including the other end and a second distal portion, extends through a through-hole between the second proximal portion and the second distal portion, and extends across the first wire portion, and a curved portion that extends to be curved between the first distal portion and the second distal portion and has at least a part disposed on a distal side relative to the through-hole.