Stent Removal Device with Suture Loop Mechanism
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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 and gripping the stent during removal or repositioning, especially in complex anatomical locations like the trachea.
Innovation Solution
A stent removal device featuring a suture arrangement with a hook and pusher mechanism that allows for crimping and constriction of the stent, reducing radial force and enabling safe repositioning or removal by encircling the stent with a low-friction tube and funnel-shaped end, minimizing contact with the lumen.
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 stent removal, then the stent can be constricted and removed, but a high degree of friction results between the stent components which complicates the explantation process
Solution Approach 1:
The patent extracts the friction problem by separating the constriction function from the thread-wire configuration. Instead of using multiple windings that create friction, the invention uses a simple loop configuration that minimizes contact and friction between the removal element and stent components, enabling smooth explantation.
Solution Approach 2:
The patent inverts the conventional approach by using a loop configuration that goes through eyelets rather than winding around the stent frame. This inversion reduces the contact surface area and friction between the removal element and stent, simplifying the explantation process while maintaining effective constriction capability.
2Reliability
If eyelets are provided in the stent for looping the thread, then the stent can be constricted, but sharp edges of the eyelets may cause the thread to tear or break during removal
Solution Approach 1:
The patent applies beforehand cushioning by providing rounded or beveled edges on the eyelets before the thread is looped through them. This pre-treatment prevents stress concentration and thread damage during the constriction and removal process, maintaining thread integrity throughout the procedure.
Solution Approach 2:
The patent applies local quality by modifying only the critical regions (eyelet edges) where the thread makes contact. The eyelets have rounded or beveled edges at the thread contact points while maintaining their structural function, locally improving thread compatibility without changing the overall stent design.
3Ease of operation
If forceps are used to grasp the stent for repositioning or removal, then the stent can be manipulated, but there is a risk of damage to the stent and/or surrounding tissue
Solution Approach 1:
The patent introduces an intermediary mechanism (the loop-and-eyelet system) that mediates between the operator and the stent. Instead of directly grasping the stent with forceps which risks tissue damage, the loop engages with the eyelets to provide controlled manipulation and constriction, reducing direct contact forces on surrounding tissue.
Solution Approach 2:
The patent segments the manipulation function into two parts: the loop provides distal engagement with the stent through eyelets, while the proximal end of the loop provides controlled pulling force. This segmentation allows precise manipulation without concentrated forces that could damage tissue or the stent structure.
4Ease of operation
If the stent is grasped with forceps in its deployed state with an expanded diameter, then the stent can be manipulated, but the vocal chords may be damaged in tracheal applications
Solution Approach 1:
The patent applies preliminary action by providing the loop and eyelet configuration during stent deployment. This allows the loop to be engaged with the eyelets while the stent is still in place, enabling subsequent constriction and removal without needing to grasp the expanded stent with forceps, thereby preventing vocal cord damage in tracheal applications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively reduces the risk of stent and tissue damage, facilitates easy access and removal, and allows for precise repositioning without expanding the stent, suitable for both vascular and nonvascular applications.
Implementation Method 1
The support frame can be radially constricted by pulling on the thread ends that are each provided with a loop or the like, creating a 'purse-string' effect
Implementation Method 2
enabling safe repositioning or removal by encircling the stent with a low-friction tube and funnel-shaped end
Data Source
AI summary
A stent removal device for removing or repositioning a stent from within a lumen is provided. The stent typically comprises at least one element arranged circumferentially about the stent. The stent removal device includes a tube positioned within the lumen proximate to the stent, wherein the tube is capable of receiving at least a portion of the stent. The stent removal device also includes a pusher positioned within the tube capable of engaging the stent and/or the element. The stent removal device further includes a hook positioned within the tube and including a hook member capable of engaging the element such that force applied to the hook causes the stent to purse string.