Pig-Tail Stent Kit with Conformal Inner Catheter
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Solution Overview
Problem
Pig-tail shaped stents are difficult to restore to their characteristic shape when an inner catheter is left inserted for a long time, making them challenging to place correctly and requiring time-consuming reinsertion if they are pushed too far, as existing delivery systems do not allow for reliable restoration of the stent's arcuate shape or easy retrieval.
Innovation Solution
A stent kit comprising a pig-tail shaped stent tube with a removable inner catheter that matches the arc-shaped parts of the stent, allowing the stent to maintain its shape and enabling easy insertion and retrieval, along with a pusher catheter for coupling and potential straightening to facilitate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an inner catheter is left inserted in a pig-tail stent for a long time, then the stent can be easily handled and positioned, but the stent cannot restore its characteristic pig-tail shape
Solution Approach 1:
The stent is pre-formed with arc-shaped parts at its ends before insertion. The memory effect is built into the stent structure in advance, so that when the inner catheter is removed, the stent automatically restores its pig-tail shape without requiring additional actions during the procedure.
2Productivity
If a pig-tail stent is pushed too far forward, then placement is complete, but the stent cannot be pulled back and requires time-consuming removal and reinsertion
Solution Approach 1:
The coupling between the inner catheter and stent is designed to be dynamic and controllable. During the procedure, the inner catheter remains coupled to push the stent forward. When retrieval is needed, the coupling can be easily released by pulling the inner catheter, allowing the stent to be pulled back without complex manipulation or permanent attachment.
3Force
If coupling means are assembled between stent and pusher catheter, then the stent can be pushed forward effectively, but the system becomes more complex and harder to assemble
Solution Approach 1:
The coupling means integrates the pusher catheter and stent into a unified assembly. The inner catheter serves dual purposes: as a pusher and as part of the coupling mechanism. This merging eliminates the need for separate complex coupling devices while maintaining effective pushing capability.
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
Enables reliable restoration of the stent's shape and allows for the pig-tail stent to be pulled back if necessary during placement, reducing the complexity and time required for insertion and placement procedures.
Implementation Method 1
The inner catheter and stent tube are arranged such that the inner catheter can be pulled out of the stent tube... the arc-shaped part or parts of the stent are not deformed by the inner catheter even if the inner catheter remains inside the stent for a long time. Thus, the shape of the arc-shaped part or parts is reliably restored when the inner catheter is pulled out.
Data Source
AI summary
In a stent kit in which a stent tube has an arc-shaped part at one or both ends, an inner catheter includes an arc-shaped part fitting in, and conforming to, each arc-shaped part of the stent tube. Because of the conforming shapes, the stent tube is not deformed by the inner catheter even if the inner catheter remains within the stent tube over a long time. Consequently, the arcuate shape of the arc-shaped part or parts of the stent tube are reliably restored when the inner catheter is pulled out.