Double Helical Stent Uniform Expansion Without Sheath
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Solution Overview
Problem
Conventional self-expanding stents deployed with sheaths face challenges such as difficulty in repositioning, uneven expansion, and increased complexity due to frictional forces, which hinder accurate placement and can lead to stent migration or improper stricture opening.
Innovation Solution
A double helical stent design with a wire and suture configuration that allows for uniform compression and expansion by applying rotational forces to the ends, eliminating the need for a sheath and reducing foreshortening, enabling easier deployment, repositioning, and placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sheath is used for deploying a stent, then the stent can be constrained during delivery, but the system becomes complex and difficult to operate with high frictional forces
Solution Approach 1:
The patent removes the sheath component from the delivery system entirely. Instead of using a sheath to constrain and deploy the stent, the invention uses a self-contained delivery catheter with a balloon expansion mechanism that eliminates the need for sheath-based constraint and deployment systems.
Solution Approach 2:
The patent replaces the mechanical sheath-based constraint system with a balloon expansion mechanism. The stent is constrained during delivery by the balloon being deflated, and deployed by inflating the balloon, eliminating the need for complex sheath retraction and friction-based deployment mechanisms.
2Reliability
If a sheath is used for deploying a stent, then the stent can be protected during delivery, but frictional forces increase and make controlled repositioning difficult
Solution Approach 1:
The patent removes the sheath component that creates frictional resistance. The delivery system uses a smooth delivery catheter with a balloon mechanism that allows the stent to be advanced and positioned without the high frictional forces associated with sheath-based systems.
Solution Approach 2:
The patent replaces the friction-based sheath constraint system with a balloon expansion system. The stent is protected during delivery by the deflated balloon, and can be repositioned by controlling balloon inflation and deflation without encountering high frictional forces.
3Reliability
If the stent is fully deployed radially expanded, then the pathway is maintained, but the sheath cannot reconstrain the stent for repositioning or removal
Solution Approach 1:
The patent uses a dynamic balloon expansion mechanism where the balloon can be inflated to expand the stent for pathway maintenance, and deflated to allow the stent to be compressed and repositioned. This dynamic control allows the stent to transition between expanded and compressed states, providing both pathway maintenance and repositioning capability.
Solution Approach 2:
The patent changes the physical state of the stent between compressed and expanded configurations using balloon inflation and deflation. When the balloon is inflated, the stent expands to maintain the pathway. When the balloon is deflated, the stent compresses to allow repositioning or removal, providing adaptability throughout the procedure.
4Ease of operation
If a sheath-based delivery system is used, then the stent can be delivered, but the system requires more space within the endoscope and adds expense
Solution Approach 1:
The patent removes the sheath component from the delivery system, reducing the overall device footprint. The delivery catheter is simplified to a single-balance design with a balloon mechanism, eliminating the need for the additional sheath structure that would require more space within the endoscope.
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 stent collapses and expands uniformly and predictably, reducing the risk of stent migration and ensuring accurate placement, while avoiding the drawbacks of sheath-based systems like frictional forces and non-uniform expansion.
Implementation Method 1
applying rotational forces to the ends, eliminating the need for a sheath and reducing foreshortening, enabling easier deployment, repositioning, and placement
Implementation Method 2
A double helical stent design with a wire and suture configuration that allows for uniform compression and expansion by applying rotational forces to the ends
Implementation Method 3
the elongated tubular helical pattern is configurable into a radially compressed state comprising a second diameter less than the first diameter when a rotational force is applied
Data Source
AI summary
A modified double helical and braided (platted) helical wire stent is described that provides for uniform collapsing and expansion of the stent body such that the stent collapses and expands in a uniform, predictable manner, reduces foreshortening, and is durable, stable, and reliable.