Flexible Three-Arm Snare for Stone Retrieval
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Solution Overview
Problem
Conventional snare instruments are inefficient in trapping foreign bodies and concretions due to limitations in their snaring function and are costly to produce.
Innovation Solution
A snare instrument with noose arches extending over multiple bending tube circumferential spacings, forming an intersecting structure that allows for a 360° noose and synchronized axial movement of base portions to enhance trapping and ease of detachment, while being cost-effective to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional snare instruments are used, then the structure is simple and production cost is low, but the snaring function is inefficient and trapping reliability is poor
Solution Approach 1:
The snare structure is divided into multiple bending tubes (first, second, and third bending tubes) arranged circumferentially, with noose wires distributed among them. This segmentation allows the snare to engage targets from multiple points simultaneously, improving trapping reliability while maintaining manageable structural complexity through modular arrangement.
Solution Approach 2:
The noose wires are configured to extend not only axially but also in the circumferential direction, creating a three-dimensional noose structure. The noose arches form loops that can encircle targets from multiple angles, transforming a simple linear closure into a volumetric trapping mechanism that significantly enhances snaring effectiveness.
2Reliability
If noose arches extend over multiple bending tube circumferential spacings to form 360° noose, then snaring function is improved, but device complexity increases
Solution Approach 1:
The noose wires serve multiple functions: they provide structural support for the bending tubes, create the noose arches for target engagement, and enable circumferential encirclement. This multi-functionality allows the same structural elements to achieve both structural integrity and enhanced snaring capability without proportionally increasing complexity.
Solution Approach 2:
The noose wires are integrated with the bending tube structure, where the wires extend through and are supported by the bending tubes. This merging of components allows the noose arches to be formed using the same structural framework, reducing the need for separate complex mechanisms while achieving 360° encirclement capability.
3Ease of operation
If intersecting noose structure is formed, then detachment from tissue wall is easier due to shearing effect, but manufacturing complexity increases
Solution Approach 1:
The noose structure is designed to dynamically transition from an open configuration during insertion to an intersecting closed configuration during target engagement. The intersecting noose arches create shearing forces that facilitate detachment, while the dynamic nature of the structure allows it to adapt its geometry during the procedure, reducing manufacturing complexity by relying on functional configuration rather than fixed complex geometry.
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 snare instrument provides reliable trapping and secure holding of foreign bodies and concretions with improved snaring functions and reduced production costs, facilitating easy detachment from tissue walls.
Implementation Method 1
the flexible bending tubes, and therefore the snare structure as a whole, return elastically again to their opened starting position
Data Source
AI summary
An endoscopic instrument provides a flexible three-arm snare structure that is adapted to retrieve stones from a human body.