Endograft Introducer Capsule Assembly Retrieval Mechanism
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Solution Overview
Problem
Existing capsule assemblies for stent graft introducers can dislodge deployed stent grafts due to the distally facing opening of the capsule, which engages with the stent graft and causes premature removal during retrieval.
Innovation Solution
A capsule assembly with a retriever having a plug portion and a tail portion, where the plug portion has a lead-in surface and the tail portion includes a barb to prevent re-entry into the capsule tube, ensuring secure engagement and stable retrieval of the stent graft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capsule with a distally facing opening is used to encompass the stent graft during introduction, then the stent graft can be securely contained during deployment, but the capsule edge can engage with the deployed stent graft and cause dislodgement during retrieval
Solution Approach 1:
The patent inverts the traditional capsule design by providing a capsule assembly where the capsule tube is slidably movable relative to the retriever, allowing the capsule to be pulled back along the retriever rather than remaining fixed. This inversion of the retrieval mechanism prevents the capsule edge from engaging with and dislodging the stent graft while maintaining secure containment during deployment.
Solution Approach 2:
The patent introduces dynamic movement capability to the capsule assembly by making the capsule tube slidably movable relative to the retriever. This dynamic configuration allows the capsule to transition from a fixed state during deployment to a movable state during retrieval, enabling the capsule to be pulled back along the retriever without engaging with the deployed stent graft.
2Ease of operation
If moveable capsule plugs are provided to facilitate retrieval, then the capsule can be removed from the stent graft, but known capsule assemblies have various shortcomings including potential dislodgement and complex structures
Solution Approach 1:
The patent segments the capsule assembly into distinct functional components: a retriever with a lead-in surface for engagement, a capsule tube for containing the stent graft, and a tail portion with a barb for securing to the retriever. This segmentation allows each component to perform its specific function independently, simplifying the overall structure while enabling easy retrieval through coordinated movement of the segments.
Solution Approach 2:
The patent uses the retriever as an intermediary component between the capsule tube and the operator. The retriever's lead-in surface engages with the capsule tube, and the tail portion with the barb secures to the retriever, creating a controlled intermediary mechanism that facilitates easy retrieval without requiring complex direct manipulation of the capsule itself.
3Device complexity
If the capsule tube is fixed relative to the retriever, then the structure is simple, but the capsule cannot be pulled back along the retriever and may dislodge the stent graft
Solution Approach 1:
The patent transforms the fixed relationship between the capsule tube and retriever into a dynamic sliding relationship. The capsule tube is made slidably movable relative to the retriever, allowing it to be pulled back along the retriever during extraction. This dynamic configuration prevents dislodgement of the stent graft while maintaining relatively simple structure through the use of a straightforward sliding mechanism.
Data Source
AI summary
A capsule assembly for an endograft introducer is disclosed. The assembly comprises: a capsule retriever having a plug portion and a tail portion, the plug portion having a lead-in surface, the tail portion having an elongate body extending proximally from the plug portion to an end stop feature receiver; a capsule tube having an end stop feature at a proximal end thereof and terminating in a distal end, the end stop feature and the end stop receiver arranged such that proximal movement of the capsule tube relative to the plug portion is limited; and a capsule cavity inside the capsule tube, a proximal end of a prosthesis being receivable in the cavity. The capsule tube is slidably movable with respect to the capsule retriever to a position in which the distal end of the capsule tube is adjacent to the lead-in surface of the plug portion.