Medical Stent Marker Coil for Radioscopy Visibility
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Solution Overview
Problem
Conventional medical stents for bile ducts face challenges in maintaining lumen size and visibility under radioscopy, with issues of migration and difficulty in confirming flap engagement with the stricture, especially when bent or subjected to external forces.
Innovation Solution
A medical stent design featuring a coil structure with a polyurethane elastomer outer layer and a fluorine resin inner layer, providing flexibility and resistance to collapse, along with radiopaque markers for enhanced visibility, and flaps that can engage and open to prevent migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the stent is made from soft resin to enhance ease of bending, then flexibility is improved, but the stent may collapse in the radial direction and lumen-maintaining properties deteriorate
Solution Approach 1:
The stent employs a composite structure combining soft resin material (polyurethane elastomer) with a metal mesh reinforcement layer. The soft resin provides flexibility and ease of bending, while the metal mesh reinforcement maintains lumen size and prevents radial collapse, resolving the contradiction between flexibility and structural strength.
Solution Approach 2:
The stent uses a flexible outer shell made of polyurethane elastomer that can bend easily, combined with an inner metal mesh structure that provides structural support. This allows the stent to be flexible for easy bending while maintaining lumen integrity through the reinforcing mesh.
2Ease of operation
If the stent is made from soft resin to enhance flexibility, then ease of bending is improved, but the thickness must be increased to prevent collapse, which complicates the structure
Solution Approach 1:
Instead of increasing thickness, the patent uses a composite structure where a thin layer of soft resin is combined with a metal mesh reinforcement. This allows maintaining flexibility while preventing collapse through the reinforcing mesh, avoiding the need to increase overall thickness.
Solution Approach 2:
The stent employs a thin flexible outer shell of polyurethane elastomer combined with an inner metal mesh structure. This thin-film approach provides flexibility without requiring increased thickness, as the metal mesh provides the necessary structural support.
3Reliability
If flaps are provided on the stent to prevent migration, then reliability is improved, but visibility under radioscopy becomes difficult when flaps are closed
Solution Approach 1:
The patent incorporates radiopaque markers or contrast agents that change the radiographic appearance of the stent and flaps. This allows the flaps to remain visible under radioscopy even when closed, as the radiopaque elements provide contrast against the surrounding tissues, enabling simultaneous migration prevention and visibility.
4Strength
If a metal wire mesh is added to maintain lumen size, then strength is improved, but ease of bending deteriorates
Solution Approach 1:
The stent uses a composite structure where a soft resin material (polyurethane elastomer) is combined with a metal wire mesh. The soft resin outer layer provides flexibility and ease of bending, while the inner metal mesh reinforcement maintains lumen size and provides structural strength, resolving the contradiction between these two properties.
Solution Approach 2:
The stent employs a flexible outer shell made of polyurethane elastomer that allows easy bending, combined with an inner metal mesh structure that provides lumen support. This flexible shell approach enables the stent to bend easily while the internal mesh maintains structural integrity.
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 stent maintains lumen size and resistance to collapse while being flexible and easy to bend, with improved visibility under radioscopy, reducing the risk of migration and facilitating placement and removal.
Implementation Method 1
a coil (3) formed by winding a wire (2) around an axis (C1)
Implementation Method 2
a marker coil part (32) formed by winding the wire (2) around the axis (C1) so as to be substantially close-coiling
Data Source
AI summary
A medical stent comprising a coil formed by winding a wire around an axis, an outer layer formed substantially tubular made from a first resin material, provided on an outer peripheral side of said coil and coaxial to said coil, and an inner layer formed substantially tubular made from a second resin material, provided on an inner peripheral side of said coil and coaxial to said coil.