Removable Stent With Internal Thread Guidance
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Solution Overview
Problem
Existing stents face challenges in removal due to high friction and complex grasping of thread ends, especially when new tissue growth occurs, making explantation difficult and potentially complicated.
Innovation Solution
A stent with a modular design featuring axially successive annular segments connected by positively intermeshing coupling elements and a thread system where ends are guided internally for reduced friction and easier grasping, allowing for adaptable lengths and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the support frame is surrounded by a thread or wire for removal, then the stent can be removed from the body, but high friction results between the thread and support frame making removal difficult
Solution Approach 1:
A connector is introduced as an intermediary component between the thread and the support frame. The connector is coupled to the support frame and has a threaded bore that receives the thread, serving as a mediator that reduces direct friction between the thread and support frame while enabling effective force transmission for stent removal.
Solution Approach 2:
The connector includes an x-ray visible portion that allows for detection and visualization during the removal process, enabling medical personnel to locate and manipulate the connector and thread assembly effectively during explantation procedures.
2Reliability
If the thread is guided or braided in multiple windings around the support frame to secure it, then the stent can be held firmly, but a high degree of friction results which has a disadvantageous effect on the explantation process
Solution Approach 1:
The connector serves as an intermediary that provides secure attachment of the thread to the support frame through a threaded bore, eliminating the need for multiple windings. This single-point secure connection maintains reliability while dramatically reducing friction during removal.
3Ease of operation
If the thread ends are provided with loops or the like for grasping, then the stent can be removed, but the grasping of the thread ends can be complex at times
Solution Approach 1:
The complex loop structures are extracted and replaced with a simplified connector design that has a threaded bore receiving the thread ends. The connector itself serves as the grasping point, eliminating the need for separate loops and simplifying the overall removal mechanism.
4Ease of manufacture
If a one-piece support frame is used, then manufacturing is simpler, but if an annular segment is defective the entire stent would be unusable
Solution Approach 1:
The support frame is segmented into multiple modular annular segments that can be independently manufactured and assembled. This segmentation allows defective segments to be identified and replaced individually while maintaining the functionality of the remaining segments, thereby improving overall stent reliability and reducing waste.
Data Source
AI summary
The invention is relative to a stent with a tubular support frame consisting of axially successively following, interconnected annular segments, which support frame is surrounded on its outside by a thread. The thread ends are guided via a deflection from the outside into support frame, where they are coupled by a connector consisting of a material visible in x-rays. Deflection is realized by two deflection elements in the form of eyelets provided on annular segment. Deflection elements are arranged on the circumference of support frame at an interval from one another and are provided on end-side annular segment, viewed in longitudinal direction L of the stent.