Permeable Shell Filamentary Device for Aneurysm Occlusion
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Solution Overview
Problem
Current treatments for cerebral aneurysms, such as surgical clipping and endovascular coiling, are invasive and have limitations like poor packing density, compaction due to hydrodynamic pressure, and difficulty in deploying devices in wide-necked aneurysms.
Innovation Solution
A self-expanding resilient permeable shell device made of woven elongate filaments, designed to expand radially and occlude the aneurysm neck, allowing blood flow at a velocity below the thrombotic threshold to facilitate clotting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surgical clipping is used to treat cerebral aneurysms, then the aneurysm can be effectively occluded, but the procedure becomes highly invasive with extended anesthesia time and high patient risk
Solution Approach 1:
A stent-graft device serves as an intermediary structure deployed within the parent blood vessel to redirect blood flow away from the aneurysm neck. The stent-graft acts as a mediator between the blood flow and the aneurysm sac, creating a new flow path that bypasses the aneurysm and promotes thrombosis within the aneurysm cavity without requiring direct surgical intervention on the aneurysm itself
Solution Approach 2:
The invention replaces the mechanical surgical clipping system with an endovascular delivery system. Instead of using a surgical clip applied through craniotomy, the treatment is delivered through a catheter-based system that deploys a stent-graft and embolic material minimally invasively, substituting open surgical mechanics with endovascular mechanics
2Object-affected harmful factors
If endovascular coiling is used to treat cerebral aneurysms, then the procedure is less invasive, but the packing density is poor and devices compact under hydrodynamic pressure
Solution Approach 1:
The stent-graft employs a flexible membrane or thin film structure that can be deployed radially expanded within the parent vessel. This flexible shell provides a stable framework that maintains its configuration under hydrodynamic pressure while allowing embolic material to be contained and packed effectively against the aneurysm neck
Solution Approach 2:
The invention changes the physical parameters of the treatment approach by using a radially expanded stent-graft structure that provides radial strength and structural integrity. This structural parameter change enables better containment and packing of embolic material compared to loose coiling, while maintaining the less invasive endovascular approach
3Ease of operation
If conventional stents are used to bridge the aneurysm neck, then blood flow can be redirected, but the stents lack sufficient density to effectively block flow into the aneurysm
Solution Approach 1:
The invention uses a composite structure combining a stent framework with a grafted membrane or thin film material. This composite construction provides both the structural support needed for blood flow redirection and the surface density required to effectively block flow into the aneurysm, achieving both ease of operation and reliability
4Reliability
If the permeable shell has large openings to allow blood flow, then thrombosis is promoted, but the structural integrity and stability of the device may be compromised
Solution Approach 1:
The stent-graft employs a porous or permeable membrane structure with controlled opening sizes. The porosity is designed to allow blood flow passage that promotes thrombosis while the overall membrane structure maintains sufficient structural integrity. The porous material provides the necessary balance between flow permeability for thrombosis induction and structural strength for device 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 device effectively blocks blood flow into the aneurysm, promoting thrombosis and occlusion while maintaining stability and flexibility to fit through microcatheters, thus offering a less invasive treatment option.
Implementation Method 1
self-expanding resilient permeable shell having a proximal end, a distal end, and a longitudinal axis. The permeable shell also includes a plurality of elongate resilient filaments with a woven structure
Implementation Method 2
allowing blood flow at a velocity below the thrombotic threshold to facilitate clotting
Data Source
AI summary
Methods and devices for treatment of a patient's cerebral aneurysm is described. The device includes a permeable shell having a radially constrained elongated state configured for delivery within a catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate filaments that are woven together to form a mesh. The proximal ends of each of the plurality of filaments are gathered by a proximal hub and the distal ends of each of the plurality of filaments are gathered by a distal hub. The proximal portion of the permeable shell includes a swellable polymer. The method includes advancing the implant in a microcatheter to a region of interest in the cerebral vasculature, deploying the implant within the cerebral aneurysm, and withdrawing the microcatheter from the region of interest after deploying the implant.