Repositionable Stent Graft Diameter Control
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Solution Overview
Problem
Current stent grafts are limited in their ability to adjust diameter after initial expansion, making repositioning difficult and potentially requiring additional grafts for adequate treatment, which increases procedural time and patient trauma.
Innovation Solution
A system comprising a biocompatible graft with a rotatable cannula and adjustable suture that allows the stent graft to be at least partially expanded and subsequently compressed, enabling repositioning by varying the graft's diameter through cannula rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent graft is expanded to treat the vascular defect, then the ability to provide outward pressure on the luminal wall is improved, but the ability to reposition the stent graft is worsened
Solution Approach 1:
The stent graft incorporates a dynamic diameter adjustment mechanism that allows the graft to transition between expanded and compressed states. The graft includes a compression mechanism with a first portion and a second portion that can move relative to each other, enabling the graft to be compressed after initial expansion for repositioning, then re-expanded for treatment
Solution Approach 2:
The invention changes the physical parameter of graft diameter dynamically. The graft is designed to maintain an expanded diameter for treating the vascular defect, but can be compressed to a smaller diameter for repositioning. The diameter adjustment is controlled by a compression mechanism that moves between a first position (expanded state) and a second position (compressed state)
2Object-affected harmful factors
If the stent graft is delivered in a compressed state through a catheter, then the trauma to the patient is reduced, but the ability to expand and reposition the graft is limited
Solution Approach 1:
The stent graft employs a dynamic compression and expansion mechanism that allows it to be delivered in a compressed state through the catheter (minimizing trauma) and then expanded at the target site for repositioning and treatment. The mechanism maintains adaptability throughout the entire procedure from delivery to deployment
Solution Approach 2:
The compression mechanism is divided into a first portion and a second portion that can move independently relative to each other. This segmentation allows the graft to be compressed for delivery while maintaining the capability to expand for repositioning and treatment
3Reliability
If additional stent grafts are delivered to adequately treat the defect due to initial misplacement, then the treatment effectiveness is improved, but the procedural time and patient trauma increase
Solution Approach 1:
The invention allows changing the graft diameter parameter dynamically. If misplacement is detected, the graft can be compressed to a smaller diameter, repositioned, and then re-expanded to the treatment diameter, eliminating the need to deliver additional grafts and reducing procedural time
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
Enables precise repositioning of the stent graft within the vasculature by allowing the surgeon to adjust the graft's diameter, reducing the need for additional grafts and minimizing patient trauma through controlled expansion and compression.
Implementation Method 1
the lengths of the first and second portions adjust in response to rotation of the rotatable cannula to vary the diameter of the graft
Data Source
AI summary
An endoluminal prosthesis includes an expandable stent graft (12) that includes a cannula (22) extending through a lumen of the stent graft. A suture (26) is threaded along the perimeter of the graft through openings (32) therein, with an inner end (22a) of the suture mounted to the cannula (22). The cannula (22) is rotatable relative to the graft (12) to wind or unwind the suture (26) around the cannula and cause the graft to become compressed when wound or allow the graft to expand when unwound. The cannula (22) includes an attachment member (46) for retaining an inner end of the suture, and the attachment member can release the inner end of the suture when adjustment of the graft diameter is no longer desired.