Eversible Cover Retrieval Structure for Safer Clot Extraction
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Solution Overview
Problem
Existing medical procedures for removing obstructions from body lumens, particularly in the cerebral vasculature, face risks of dislodging fragments that can cause further harm and complicate the procedure due to the potential for migration and trauma to the vessel walls, especially when using stents for thrombectomy.
Innovation Solution
The use of an interventional vascular device with an eversible cover that expands against the vessel wall, allowing the cover to evert over the retrieval device as it is proximally translated, providing passive protection and reducing shearing forces by resisting movement, thus securing the obstruction for safe removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stent is used to push the clot to the side of the vessel for thrombectomy, then the obstruction can be removed, but the stent may dislodge fragments or cause trauma to the vessel walls
Solution Approach 1:
A protective cover is positioned over the stent before engagement with the clot. This cover acts as a cushioning layer that prevents direct contact between the stent and vessel walls during retrieval, thereby reducing shear forces and preventing vessel wall trauma while allowing effective thrombectomy
Solution Approach 2:
The protective cover serves as an intermediary element between the stent and the vessel wall. It mediates the interaction by providing a protective barrier that allows the stent to perform thrombectomy while preventing harmful direct contact with the vessel wall, thus reducing trauma and fragment dislodgement
2Productivity
If the retrieval device is advanced to remove the obstruction, then the blockage can be cleared, but fragments may break free and flow downstream causing additional blockages
Solution Approach 1:
The protective cover is deployed beforehand to cushion and contain the obstruction during retrieval. This prevents fragments from breaking free and migrating downstream, as the cover creates a contained environment that maintains fragment containment throughout the retrieval process
3Strength
If the stent is expanded against the clot for secure engagement, then the obstruction can be firmly held, but the friction against the vessel wall increases causing potential dislodgement
Solution Approach 1:
The device is segmented into two functional components: the stent for engaging the obstruction and the protective cover for interacting with the vessel wall. This segmentation allows the stent to provide strong engagement while the cover distributes forces along the vessel wall, reducing localized shear forces that could cause dislodgement
Solution Approach 2:
Different parts of the device have different properties optimized for their specific functions. The stent portion is designed for strong engagement with the obstruction, while the cover portion is designed to interact gently with the vessel wall, providing protection and distributing forces to prevent dislodgement
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 eversible cover mechanism minimizes the risk of dislodging fragments and vascular trauma by passively securing the obstruction during retrieval, facilitating safe and efficient removal through tortuous anatomy.
Implementation Method 1
the eversible cover being axially compliant such that when the interventional vascular device retrieval device is positioned through the shaft lumen and moved in a proximal direction, the friction of the eversible cover against the vessel wall causes the eversible cover to evert over the interventional vascular device
Implementation Method 2
the friction of the eversible cover against the vessel wall causes the eversible cover to evert over the interventional vascular device
Data Source
AI summary
The devices and methods described herein relate to improved structures for removing obstructions from body lumens. Such devices have applicability in through-out the body, including clearing of blockages within the vasculature, by addressing the frictional resistance on the obstruction prior to attempting to translate and/or mobilize the obstruction within the body lumen.