Radially Adjustable Stent Graft for Precise Aortic Deployment
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Solution Overview
Problem
Existing endovascular repair methods for aortic aneurysms face challenges in accurately deploying stent grafts to span the proximal and distal ends of the aneurysm, ensuring complete exclusion of the aneurysm sac while maintaining minimal endoleaks and preserving blood flow to vital organs, without significantly compromising surrounding structures.
Innovation Solution
A stent graft delivery system with a control rod and ligature mechanism that allows for radial constriction and release of stents, enabling precise positioning and deployment of the stent graft at the aneurysm site, allowing for rotational repositioning and axial adjustment post-expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stent graft is deployed in the aorta to treat an aneurysm, then the aneurysm sac is excluded and blood flow is restored, but the stent graft may distort or misposition after deployment, compromising the intended shape and location
Solution Approach 1:
The stent graft incorporates radially adjustable stents with ligatures that can be dynamically constricted and released. The ligatures traverse the stent struts and can be selectively tightened to radially constrict the stent, allowing dynamic adjustment of the stent graft's radial dimensions after deployment. This enables correction of positioning errors and maintenance of the intended shape without distortion.
2Reliability
If the stent graft is firmly anchored in the aorta to prevent migration, then the aneurysm is effectively excluded, but the delivery system lacks the ability to reposition the stent graft if initial positioning is inaccurate
Solution Approach 1:
The radially adjustable stent mechanism allows the stent graft to be securely anchored through radial constriction via ligatures while maintaining the capability for repositioning. The ligatures can be released and re-tightened at different positions, enabling the operator to adjust the stent graft's location along the aorta before final anchoring, thus combining reliable anchoring with repositioning flexibility.
Solution Approach 2:
The delivery system maintains continuous control over the stent graft's position and shape through the ligature mechanism. The ligatures remain under tension during the positioning process, allowing continuous adjustment and refinement of the stent graft's location and configuration until optimal positioning is achieved, rather than requiring release and re-deployment.
3Strength
If the stent graft is designed with a fixed radial shape to maintain structural integrity, then the stent provides reliable support, but it cannot be adjusted to accommodate variations in patient anatomy or correct positioning errors
Solution Approach 1:
The stent incorporates ligatures that traverse its struts, enabling dynamic radial adjustment. The ligatures can be selectively tightened to radially constrict the stent, changing its radial dimensions while maintaining structural integrity. This allows the stent to adapt to variations in patient anatomy and correct positioning errors without compromising its strength and support function.
Solution Approach 2:
The radial dimensions of the stent are changed by adjusting the tension on the ligatures. By varying the ligature tension, the stent's radial parameter can be modified to accommodate different anatomical conditions or positioning requirements, while the stent's structural integrity is maintained through controlled constriction rather than compromising its design strength.
Data Source
AI summary
A stent graft delivery system and method for implanting a stent graft includes and employs at least one control rod that extends along a luminal wall of a stent graft and at least one ligature. The ligature extends about radial stents. Rotation of the control rod or a tube extending about the control rod wraps the ligature about the control rod, thereby radial constricting the stent about which the ligature extends.