Snare Instrument Tubular Capture Structure

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Solution Overview

Problem

Existing safety wire instruments face challenges in achieving good catch functionality and high functional reliability while being manufactured with minimal effort, particularly in medical applications where they need to efficiently capture and remove foreign bodies from body tissues.

Innovation Solution

A safety wire instrument with a cup-shaped safety section and a distal safety opening is designed, featuring axial slits that form a capture port with a specified length and configuration, allowing for efficient trapping and retrieval of particles without the need for wire connections, using a one-piece tubing structure that can be easily bent and folded for deployment and retrieval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a basket-shaped capture structure with multiple wire sections is used to capture particles transversely, then the capture functionality is improved, but the device complexity and manufacturing effort increase due to multiple wire connections and welding joints

Engineering Contradiction:
Improvecapture functionalityVSAvoidwire connections
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple separate wire sections are merged into a single continuous tube that is slit and bent to form the capture structure. The tube is provided with longitudinal slots and bent to form a capture basket with front and rear cup bodies, eliminating the need for multiple wire connections and welding joints while maintaining capture functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single tube is segmented through longitudinal slots into multiple wire sections that form the capture basket structure. These slots create front wire sections and rear wire sections that are connected through curved sections, providing both segmentation for capture openings and continuity for structural integrity.

Inventive Principle:
Principle #1Segmentation

2Strength

If wire connections and welding joints are used to assemble the capture structure, then the structural integrity is improved, but the functional reliability decreases due to potential breakage or failure at connection points

Engineering Contradiction:
Improvestructural integrityVSAvoidfunctional reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention uses a single continuous tube without any welding joints or separate wire connections. The tube is slit and bent to form the complete capture structure, ensuring structural integrity throughout the entire assembly and eliminating potential failure points at connection locations.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If a one-piece tubing structure is used to simplify manufacturing, then the ease of manufacture is improved, but the capture cross-section and functionality may be compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcapture functionality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The single tube is segmented through longitudinal slots into multiple wire sections that form the capture basket. The slots are positioned and dimensioned to create front wire sections and rear wire sections with appropriate curved connections, ensuring both manufacturing simplicity and effective capture functionality with adequate capture cross-section.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tube is bent in multiple dimensions to form the three-dimensional capture basket structure with front and rear cup bodies. The bending creates radial and axial dimensions that provide adequate capture cross-section while maintaining the one-piece construction for manufacturing simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If the capture structure is designed with a large capture cross-section, then the particle capture efficiency is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveparticle capture efficiencyVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The tube is segmented into front wire sections and rear wire sections through longitudinal slots, with the slot positioning and dimensions optimized to create adequate capture openings and capture cross-section. The curved sections connecting the wire sections are designed with appropriate radii to maintain structural integrity while forming the desired capture geometry.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3119292B1Snare instrument with snare structure composed of a tubular piece
Publication Date: 2023.08.16 COLOPLAST AS
  • EP3119292B1 patent drawingFigure 1~6
  • EP3119292B1 patent drawingFigure 7~10
  • EP3119292B1 patent drawingFigure 11~16

AI summary

2.1 The invention relates to a snare instrument with a snare structure (1) which is formed by slitting and bending open a tubular piece (2) and which has a proximal base portion (3) and, extending axially forwards from the latter, a distal catching portion (4), and which is movable between a catching position, in which it is moved forwards out of an enclosure (6) with the catching portion folded open, and a securing position, in which it is moved back at least partially into the enclosure with the catching portion folded in. 2.2 In the snare instrument according to the invention, the catching portion, in the folded open state, has a bell shape with a distal catching opening (7). For this purpose, a distal end area of the tubular piece is provided with open axial slits of suitable length introduced from the direction of the distal end of the tubular piece, and, lying between these, with associated closed axial slits which end at a distance in front of the distal end of the tubular piece and are of greater length than the open axial slits. Through the open and closed axial slits, wire sections are formed from the tubular piece which, when the tubular piece is bent open, form peripheral portions of the catching opening. 2.3 Use, for example, as medical instruments for catching stones.