Nested Anti-Migration Stent With Silicone Film
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Solution Overview
Problem
Conventional stents for expanding narrowed or blocked lumens in the body are prone to migration due to external forces such as body fluids, food pressure, or body movement, and are difficult to remove after a procedure.
Innovation Solution
An anti-migration stent design featuring a first stent with a hollow cylindrical shape made of super elastic shape memory alloy and PTFE film parts, combined with a second stent that is shorter and fitted over the first stent, using a silicone film to facilitate easy removal and prevent migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stent is inserted to expand a narrowed lumen, then the lesion area is expanded and lumen function is restored, but the stent migrates when external forces occur due to body fluids, food pressure, or body movement
Solution Approach 1:
The patent employs a nested structure where an inner stent is placed inside an outer stent. The inner stent has a smaller diameter and is positioned within the outer stent's cylindrical body, creating a nested configuration. This nested arrangement enhances position stability through combined structural support while preventing migration through the interaction between the two stents
Solution Approach 2:
The stent system is divided into two separate stent components rather than a single monolithic structure. The inner stent and outer stent function as independent segments that work together, allowing each to contribute differently to stability and migration prevention while maintaining individual structural integrity
2Duration of action of stationary object
If a stent is left in place for an extended period to maintain lumen expansion, then the lesion area remains open, but the stent becomes difficult to remove and may cause lumen damage
Solution Approach 1:
The patent incorporates dynamic characteristics through the interaction between the inner and outer stents. The flexible membrane structure and the relative positioning of the two stents allow the system to adapt its rigidity and interaction forces over time, facilitating easier removal after the therapeutic period while maintaining structural support during retention
Solution Approach 2:
The patent utilizes a flexible membrane structure as part of the stent design. This thin film component provides the necessary structural support to maintain lumen expansion during the retention period while allowing for controlled deformation and movement that facilitates removal, reducing the risk of lumen damage during extraction
3Reliability
If the stent structure is made more complex to prevent migration, then migration resistance is improved, but the device becomes harder to remove and more difficult to maneuver in the lumen
Solution Approach 1:
The nested configuration of the inner stent within the outer stent provides migration prevention through a relatively simple geometric arrangement. The concentric cylindrical structures interact to prevent displacement without requiring complex mechanical locking mechanisms or additional components, maintaining ease of maneuverability while improving position stability
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 effectively expands the lesion area, prevents migration during external forces, and can be easily removed after a predetermined period due to its flexible and bonded film structure, reducing the risk of lumen damage.
Implementation Method 1
a first cylindrical body formed in a hollow cylindrical shape by weaving or crossing wires made of a super elastic shape memory alloy in a mesh shape
Implementation Method 2
a first film part made of polytetrafluoroethylene (PTFE) formed on an inner surface of the first cylindrical body, with the first film part formed in a spiral shape to have predetermined intervals defined therein, and a second film part made of polytetrafluoroethylene (PTFE) formed on an entire outer surface of the first cylindrical body so that the second film part is bonded to the first film part
Data Source
AI summary
Proposed is an anti-migration stent which expands a lesion area occurring in a lumen and is prevented from migrating, is deformed to fit the lumen of a curved shape, and can be easily removed from the lumen. More specifically, the anti-migration stent includes a first stent including a first cylindrical body, a first film part, and a second film part, and a second stent including a second cylindrical body, a connection part formed by having a diameter decreasing at one side of the second cylindrical body, and a third film part made of silicone formed on the second cylindrical body and the connection part, wherein after the second stent is fitted over one side of the first stent, the one side of the first stent and the connection part are connected to each other, and the second stent is held in the lumen.