Flared Stent Graft for Secure Aortic Iliac Connection
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Solution Overview
Problem
The challenge in treating abdominal aortic aneurysms is the difficulty in securely connecting branched iliac stent grafts with bifurcated stent grafts due to the limited distance distally of the aortic bifurcation, requiring a reliable and stable fluid connection.
Innovation Solution
An iliac extension stent graft with a flared cuff, preferably a zigzag style Gianturco stent made from stainless steel or Nitinol, is designed to connect internally to a pre-deployed branched iliac graft at its distal end and extend into the leg of a bifurcated aortic stent graft at its proximal end, providing a variable and secure fluid connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate branched iliac stent graft is deployed in the common iliac artery to treat aneurysms extending into iliac arteries, then the aneurysm can be treated, but the connection between the branched iliac stent graft and the bifurcated stent graft becomes difficult and insecure due to limited distance distally of the aortic bifurcation
Solution Approach 1:
The flared cuff is designed with a dynamic expansion capability, transitioning from a compressed delivery state to an expanded flared configuration at the distal end. This dynamic transformation allows the cuff to adapt to the limited space distally of the aortic bifurcation while maintaining secure connection, resolving the contradiction between connection security and ease of operation in constrained anatomical spaces
Solution Approach 2:
The flared cuff introduces a dimensional change by expanding radially outward to create a flared configuration. This dimensional transformation increases the effective surface area for attachment and creates a mechanical interlock geometry that enhances connection security within the limited longitudinal distance available distally of the aortic bifurcation
2Reliability
If the distance distally of the aortic bifurcation is limited, then the available space for connection is reduced, but a secure connection between stent grafts is still required
Solution Approach 1:
The flared cuff changes the geometric parameters of the connection interface by creating a flared configuration with increased radial dimension. This parameter change allows the connection to achieve sufficient security through enhanced surface area and mechanical interlocking, compensating for the limited longitudinal distance available distally of the aortic bifurcation
3Reliability
If a flared cuff is added to the distal end of the stent graft to improve connection security, then connection reliability is enhanced, but the device complexity increases
Solution Approach 1:
The flared cuff is merged with the stent graft structure as an integrated component rather than a separate attachment. This merging approach enhances connection security while minimizing the increase in device complexity, as the flared cuff and stent graft form a unified structure that can be deployed together as a single unit
Data Source
Figure 1~3A
Figure 3~3B
Figure 5A~6
AI summary
A leg extension (10) for a stent grafting system to connect between an aortic graft (120) and an iliac graft (180). The leg extension is a tubular body (12) of a biocompatible graft material with self-expanding stents (15) connected along the length of the tubular body and the tubular body having a distal end (24) with a connection region (14). The connection region has a flared stent (16) defining an external frusto-conical surface to provide a connection arrangement to engage within an internally flared portion (90) of an iliac graft.