Electrospun Stent Covering for Aneurysm Delivery
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Solution Overview
Problem
Existing medical stents for treating aneurysms in small cerebral blood vessels face challenges in compressibility due to textile coverings, which limit their ability to be delivered through small, tortuous vessels while still effectively covering the aneurysm and allowing nutrient supply.
Innovation Solution
A stent with a highly flexible, compressible mesh structure combined with an electrospun fabric covering that has irregular pores, allowing for high permeability and thinness, enabling the stent to be compressed to a small diameter and delivered through small vessels while maintaining the ability to cover aneurysms and supply nutrients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent is provided with a textile covering to cover an aneurysm, then the aneurysm coverage function is improved, but the compressibility of the stent is compromised
Solution Approach 1:
The patent applies porous electrospun fabric as the covering material, which has controlled porosity allowing blood flow while providing aneurysm coverage. The porous structure enables the fabric to be thin yet functional, resolving the contradiction between coverage reliability and compressibility by allowing the covering to maintain its function at reduced thickness.
Solution Approach 2:
The patent uses composite construction combining a metal mesh structure with an electrospun fabric layer. This composite material approach allows the metal mesh to provide structural support and compressibility while the fabric layer provides aneurysm coverage, thus resolving the contradiction between these two requirements.
2Reliability
If multiple layers of electrospun structure are overlaid to obtain low porosity, then the aneurysm coverage is improved, but the wall thickness increases compromising compressibility
Solution Approach 1:
The patent changes the porosity parameter of the electrospun fabric by controlling the electrospinning process parameters (voltage, flow rate, distance) to achieve the desired balance between coverage and thickness. Instead of adding multiple layers, the porosity is optimized within a single or minimal layer structure.
Solution Approach 2:
The patent utilizes the inherent porosity control capability of electrospun materials to achieve effective aneurysm coverage with controlled pore size and distribution, eliminating the need for multiple thick layers and thereby maintaining wall thinness and compressibility.
3Reliability
If a nonwoven fabric with impermeable inner layer and sponge-like outer layer is used, then the liquid permeability control is improved, but the wall thickness increases limiting compressibility
Solution Approach 1:
The patent replaces the multi-layer nonwoven fabric structure with a single-layer electrospun fabric having controlled porosity. The electrospun structure provides sufficient liquid permeability control through its nanofiber mat configuration without requiring multiple layers, thus maintaining thin walls and high compressibility.
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 solution allows for the successful delivery and deployment of the stent in small blood vessels with reduced delivery forces, maintaining effective coverage of aneurysms and preventing rupture by ensuring sufficient nutrient supply through high permeability without compromising structural integrity.
Implementation Method 1
The covering is formed from electrospun fabric which has irregular pores. The covering comprises at least 10 pores with a size of at least 15 μm2 over an area of 100,000 μm2
Data Source
AI summary
A medical device for inserting into a hollow organ of the body, said medical device having a compressible and expandable lattice structure made of webs, which are integrally connected to each other by web connectors and which bound closed cells of the lattice structure, wherein the web connectors each have a connector axis extending between two cells which, in a longitudinal direction of the lattice structure, are adjacent to each other. During the transition of the lattice structure from the production state to a compressed state, the web connectors rotate in such a way that an angle between the connector axis and a longitudinal axis of the lattice structure changes, in particular increases, during the transition of the lattice structure from a completely expanded production state to a partially expanded intermediate state.