Removable Stent with Segmented Flexible Elements
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Solution Overview
Problem
Current stent removal and repositioning technologies face challenges such as high friction between stent components, risk of damage to the stent and surrounding tissue, and difficulty in accessing the stent for removal, especially when tissue has grown over the suture thread.
Innovation Solution
A stent design featuring engageable members that can be individually engaged by a stent removal device to reduce the stent's diameter without creating a purse-string effect, using a scaffolding of struts and flexible elements with eyelets and suture material, and a stent removal assembly with prongs and gripping members that bias between open and closed positions to facilitate easier removal and repositioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thread or wire is guided or braided in multiple windings around the support frame to enable removal, then the stent can be removed or repositioned, but a high degree of friction results between the two stent components which has a disadvantageous effect on the explantation process
Solution Approach 1:
The continuous thread or wire is divided into multiple separate flexible elements (e.g., three elements) that are independently secured to the scaffolding at different circumferential positions. Each element functions as an independent engagement point, reducing the cumulative friction that would occur with a single multi-winding thread while maintaining effective stent compression and removal capability.
2Reliability
If forceps or similar instruments are used to grasp the thread ends to reposition or remove the stent, then the stent can be removed, but this can be complex when tissue has grown over the suture thread and may lead to damage to the stent or difficulty in accessing the thread
Solution Approach 1:
The flexible elements are configured to extend from the exterior of the stent into the interior region, creating multiple access dimensions. This allows removal instruments to engage the elements from either the proximal end (exterior) or the distal end (interior), providing dimensional flexibility that overcomes tissue overgrowth obstacles and simplifies the removal procedure.
3Reliability
If grasping forceps are used to grab the struts of the stent at a proximal end for removal, then the stent can be removed from the deployment site, but this risks damage to the lumen or the stent as the proximal end may be difficult to access
Solution Approach 1:
The flexible elements serve as intermediary structures between the removal instrument and the stent struts. Instead of directly grasping the struts (which risks damage), the instrument engages the flexible elements that are secured to the struts, transferring the removal force through this intermediary medium and reducing the risk of direct contact damage to both the stent and surrounding lumen.
Data Source
AI summary
A removable stent for placement within a lumen is provided. The stent includes a scaffolding of struts formed from a tube of memory material and having a proximal end, a distal end, and an interior region. The stent includes at least two flexible elements independently secured to the scaffolding and spaced circumferentially from one another. Each element defines an engageable member such that an inwardly directed force applied to the engageable members reduces a diameter of the scaffolding.