Tapered Stent Graft Extraction Sheath for Atraumatic Removal
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Solution Overview
Problem
The extraction of endovascular stent grafts often causes significant damage to the vessel wall due to the engagement of prongs, contributing to high morbidity during the removal process.
Innovation Solution
A cylindrical device with a tapered sidewall and blunt edges is used to slide over the stent graft, compressing it and releasing prongs from the vessel wall, allowing for atraumatic removal by minimizing contact and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stent grafts are made durable and integrated with tissue, then reliability is improved, but device complexity and difficulty of removal increase
Solution Approach 1:
A delivery sheath acts as an intermediary device to facilitate the extraction of the stent graft. The sheath is positioned over the stent graft, engages it, and provides controlled manipulation for removal. This intermediary tool resolves the contradiction by enabling extraction of a device that was designed for durability and integration, without requiring modification to the stent graft itself.
Solution Approach 2:
The extraction system segments the removal process into distinct components: the delivery sheath for engagement, manipulation elements for control, and extraction mechanisms for removal. This segmentation allows the stent graft to maintain its integrated design while the extraction system provides the necessary complexity only where needed for removal.
2Reliability
If stent grafts are designed for permanent implantation, then reliability is improved, but ease of operation for removal deteriorates
Solution Approach 1:
The delivery sheath serves as a mediator that enables easy operation for removal without compromising the permanent implantation design. The sheath engages the stent graft and provides mechanical advantage for controlled extraction, making the removal process as easy as reinsertion while the stent graft itself remains designed for permanent implantation.
Solution Approach 2:
The extraction system inverts the approach by using a delivery device (sheath) in reverse - instead of delivering the stent graft, the same type of device is used to extract it. This inversion provides ease of operation for removal while maintaining the original permanent implantation design of the stent graft.
3Adaptability or versatility
If stent grafts are made resilient and adaptable, then adaptability is improved, but ease of extraction deteriorates
Solution Approach 1:
The delivery sheath acts as an intermediary that overcomes the resistance to extraction caused by the stent graft's resilience and adaptability. The sheath engages the stent graft structure and provides controlled manipulation, enabling extraction despite the device's designed adaptability to surrounding tissues.
Solution Approach 2:
The extraction system employs dynamic manipulation elements that can adapt to the stent graft's resilient structure during extraction. These elements provide controlled forces and movements that work with the stent graft's adaptability rather than against it, facilitating removal while maintaining the device's inherent dynamic properties.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5B
AI summary
A device for extracting an endovascular stent graft from a vessel including a cylindrical body and an opening formed in the cylindrical body. The cylindrical body has a first open end, a second open end, and a sidewall surrounding a hollow bore of the cylindrical body. The opening is formed in the sidewall between the first open end and the second open end forming a first ring portion at the first open end and a second ring portion at the second open end. Additionally, a thickness of the sidewall at the first open end tapers toward the opening and wherein a thickness of the sidewall at the second open end tapers toward the opening such that the hollow bore is narrower at each end than at the opening.