Actively Controllable Stent Graft for Irregular Anatomy
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Solution Overview
Problem
Current endovascular stent grafts face challenges in achieving a secure seal and precise positioning within irregularly shaped anatomic spaces, such as aortic aneurysms, due to limitations in radial force distribution and inability to reposition after deployment, leading to issues like migration and leakage.
Innovation Solution
The development of actively controllable stent grafts with adjustable elements that can change configuration to accommodate irregular anatomies, featuring expandable sealable collars and retractable retention tines, allowing for remote actuation and repositioning post-deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing endografts use fixed radial force from stent material to secure a seal, then the device structure remains simple, but the device cannot accommodate irregular anatomic spaces and irregularities in the aortic wall leading to migration and leakage
Solution Approach 1:
The stent graft incorporates an actively controllable stent with adjustable elements that can change configuration post-deployment. The stent includes multiple struts with adjustable positions and angles, allowing the device to dynamically adapt to irregular anatomic spaces and aortic wall irregularities, resolving the contradiction between adaptability and structural simplicity
Solution Approach 2:
The stent geometry parameters (strut positions, angles, and spacing) can be actively modified after deployment to optimize the seal and accommodate anatomical variations. This allows the device to transition from a fixed structure to one with variable parameters, improving adaptability without requiring complete structural redesign
2Reliability
If existing endografts are deployed in place, then the deployment process is straightforward, but the implant cannot be repositioned leading to migration and leakage
Solution Approach 1:
The actively controllable stent allows for post-deployment repositioning and adjustment of the stent graft. The adjustable elements can be actuated remotely to move the device to the optimal position, ensuring reliable sealing and preventing migration while maintaining ease of operation
Solution Approach 2:
The system incorporates the ability to assess deployment accuracy and make adjustments based on observed positioning. The adjustable elements allow real-time feedback and correction of placement errors, improving position stability without compromising ease of operation
3Manufacturing precision
If pre-sizing is required based on CAT-scan measurements, then the deployment process becomes complex and time-consuming, but mis-sized grafts lead to unstable seals and migration
Solution Approach 1:
The actively controllable stent allows for post-deployment adjustment of size and configuration, eliminating the need for precise pre-sizing. The device can be resized and reconfigured after implantation to achieve optimal fit, reducing the complexity of the sizing process while improving sizing accuracy
Solution Approach 2:
The stent is designed with adjustable elements that can be configured after deployment to achieve the optimal size and shape. This preliminary configuration capability allows the device to adapt to the actual anatomy rather than relying on pre-deployment measurements, simplifying the overall process
4Reliability
If barbs or hooks are incorporated to retain the endograft, then retention improves, but the device structure becomes more complex and invasive
Solution Approach 1:
The actively controllable stent provides retention through dynamic adjustment of stent geometry and radial force distribution, eliminating the need for barbs or hooks. The adjustable elements can be configured to optimize anchoring to the aortic wall, improving retention while maintaining simpler device structure
Solution Approach 2:
The stent parameters (radial force, strut configuration, and expansion ratio) can be actively modified to enhance retention without adding mechanical anchoring features. This allows optimization of the seal and retention through parameter adjustment rather than structural complexity
Data Source
AI summary
Sealable and repositionable implant devices are provided to increase the ability of endovascular grafts and valves to be precisely deployed or re-deployed, with better in situ accommodation to the local anatomy of the targeted recipient anatomic site, and with the ability for post-deployment adjustment to accommodate anatomic changes that might compromise the efficacy of the implant. A surgical implant includes a self-expanding stent of a shape-memory material set to a given shape. The stent has a wall with a portion having a first thickness and a second portion having a thickness greater than the first. The second portion defines a key-hole shaped longitudinal drive orifice. The implant includes a selectively adjustable assembly having adjustable elements and being operable to force a configuration change in at least a portion of the self-expanding stent. The adjustable elements have a part rotatably disposed within the longitudinal drive orifice.