Helical Side Arm Tie Down for Stent Graft Positioning
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Solution Overview
Problem
The correct visualization and placement of helically extending side arms in stent grafts during introduction procedures are hindered due to distortion during assembly onto introduction devices, making it difficult to accurately position the open end of the side arm with respect to branch vessels.
Innovation Solution
A temporary tie down arrangement using tie down wires stitched into the graft material to hold the side arm against the tubular body, ensuring it remains in a desired position during loading onto a deployment device, with radiopaque markers aiding visualization and a resilient reinforcing ring at the open end for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the side arm is allowed to extend helically around the stent graft body, then the side arm can reach branch vessels in the aorta, but the side arm distorts out of its helical position during assembly onto the introduction device, making correct radiographic visualization difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming the side arm in its desired helical configuration and temporarily constraining it in that position before the actual deployment procedure. The side arm is pre-shaped to extend helically around the stent graft body, and temporary tie-down arrangements are applied beforehand to maintain this configuration during assembly and introduction, ensuring correct radiographic visualization is achieved when the side arm is released at the deployment site.
2Ease of operation
If the side arm is constricted into an introduction device under a delivery sheath for introduction into a patient, then the stent graft can be introduced using endovascular techniques, but the side arm distorts out of its helical position making correct radiographic visualization very difficult
Solution Approach 1:
The patent uses temporary tie-down arrangements as intermediary elements that mediate between the side arm and the stent graft body during the introduction procedure. These tie-downs temporarily constrain the side arm to maintain its helical position and associated radiographic markers in view, allowing the physician to visualize the side arm's position relative to branch vessels even while the device is being introduced through the delivery sheath. The intermediary tie-downs are removed or released after deployment.
3Manufacturing precision
If the side arm is held flat against the tubular body during loading, then the side arm remains in its desired position for introduction, but additional temporary tie down arrangements are required
Solution Approach 1:
The patent applies the discarding and recovering principle by using temporary tie-down arrangements that are discarded (removed or released) after they have served their purpose during assembly and introduction. The temporary tie-downs are applied to hold the side arm in its desired position during loading and introduction, then they are discarded once the side arm is deployed and no longer needs constraint. This allows the use of additional components during assembly without permanently increasing device complexity.
Data Source
AI summary
An arrangement for temporarily retaining a side arm (36) of a stent graft (30) in a selected position during loading thereof onto a deployment device, the side arm extending from an ostium (38) in the tubular body (32) and substantially helically around and along the tubular body to an open end (40). A first tie down wire (48) is stitched through the tubular body and through the side arm and then through the biocompatible graft material of the tubular body at the open end of the side arm. The stent graft can then be loaded into a sheath of a deployment device for the stent graft. There can be a second tie down wire (50) stitched through the biocompatible graft material of the tubular body and through the side arm and then through the biocompatible graft material of the tubular body at the ostium end of the side arm. The first and/or second tie down wires can be withdrawn after the stent graft is loaded into the sheath or left in place until delivery.