Two-Stage Deployment Sheaths for Precise Stent Positioning
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Solution Overview
Problem
Existing minimally invasive delivery techniques for implantable medical devices face challenges in controlling the deployment and constraining expandable devices, particularly self-expanding stents and stent-grafts, to ensure precise positioning and minimize displacement during deployment.
Innovation Solution
A two-stage constraining system using knit sleeves with varying properties and release zones, allowing for sequential deployment of implantable medical devices, where one constraining member is released at a lower tension force than the other, providing controlled deployment and anchoring capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single constraining member is used to hold the expandable device, then the device can be delivered through minimally invasive access, but the device cannot be precisely positioned and controlled during deployment
Solution Approach 1:
The constraining system is divided into two separate constraining members (first and second constraining members) that can be independently controlled and released. Each constraining member has its own deployment line, allowing sequential deployment of different portions of the expandable device. This segmentation enables precise positioning control during deployment while maintaining overall system manageability.
2Ease of operation
If the constraining member is released by applying tension force, then the expandable device can be deployed, but the device may experience uncontrolled displacement
Solution Approach 1:
The release mechanism is segmented into two independent constraining members with separate deployment lines. By releasing one constraining member before the other, the system allows controlled, sequential deployment that prevents sudden uncontrolled displacement. The operator can manage the expansion process in stages, improving both ease of operation and deployment stability.
Solution Approach 2:
The first constraining member is released before the second constraining member during the deployment sequence. This preliminary action allows the expandable device to begin expanding in a controlled manner from one end, establishing a stable configuration before the second constraining member is released, thereby preventing uncontrolled displacement.
3Ease of manufacture
If the constraining member is designed to be removed after deployment, then the delivery system can be withdrawn, but the deployment process becomes more complex
Solution Approach 1:
The constraining system is designed as two separate, removable constraining members rather than a single integrated component. This segmentation allows each constraining member to be independently manipulated and removed after serving its constraining function. The simplified individual structures of each constraining member make the overall deployment procedure more manageable despite the additional component.
Data Source
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AI summary
An implantable medical device including an expandable device having a longitudinal length and operable to be compressed to a first diameter and deployed to a second diameter, wherein the second diameter is greater than the first diameter, and wherein a first portion that is less than the longitudinal length of the expandable device and a second portion that is less than the longitudinal length of the expandable device are defined on the expandable device. The medical device includes a first constraining member operable to constrain the first portion of the expandable device at the first diameter; a second constraining member operable to constrain the second portion of the expandable device at the first diameter.