Venous Sinus Stent Delivery With Graduated Flexibility and Support
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Solution Overview
Problem
Existing stent delivery systems face challenges in navigating the tortuous venous sinuses due to inadequate length, diameter mismatch, and high radial outward expansion strength, leading to potential vessel collapse, incorrect positioning, and blockage of sinus lumens, as well as increased risk of vein obstruction.
Innovation Solution
A self-expanding stent with varying flexibility and radial outward expansion strength from the distal to the proximal end, designed to match the venous sinus anatomy, combined with a flexible stent delivery system that gradually increases in stiffness, allowing for enhanced navigation and precise placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional stent with uniform properties is used, then the stent structure is simple and manufacturing is easy, but the stent cannot properly match the varying anatomy of venous sinuses leading to collapse, incorrect positioning, or vessel obstruction
Solution Approach 1:
The stent is divided into multiple segments along its length, with each segment having different properties (flexibility, radial outward expansion strength, diameter) tailored to the specific anatomical requirements of different venous sinus regions. This segmentation allows the stent to adapt to the tortuous anatomy while maintaining manageable structural complexity through modular design.
Solution Approach 2:
Different portions of the stent are assigned different local properties: the proximal end has greater radial outward expansion strength for areas requiring robust support, while the distal end has lower strength and higher flexibility for navigating tortuous anatomy. The diameter also varies along the length to match the venous sinus geometry, optimizing both adaptability and positioning accuracy.
2Strength
If the stent has high radial outward expansion strength throughout, then the stent provides sufficient support to prevent collapse, but the stent may block the sinus lumen or cause tissue damage
Solution Approach 1:
The radial outward expansion strength is distributed non-uniformly along the stent length. The proximal end maintains high strength for effective scaffolding and collapse prevention, while the distal end progressively reduces strength to minimize tissue damage and lumen blockage. This gradient design allows the stent to provide necessary support where needed without causing harmful effects in other regions.
3Stability of the object's composition
If the stent is made stiffer to maintain its shape, then the stent provides better structural support, but the stent becomes difficult to navigate through the tortuous venous sinuses
Solution Approach 1:
The stent exhibits varying flexibility along its length, with the distal end being more flexible to facilitate navigation through tortuous venous sinuses and the proximal end being stiffer to provide structural support and maintain shape. This gradient in mechanical properties allows the stent to be easily deployed while maintaining stability once positioned.
4Ease of operation
If the stent delivery system is made more flexible to navigate the venous sinuses, then the system can be positioned accurately, but the stent may be incorrectly positioned or the sinus lumen may be blocked
Solution Approach 1:
The stent delivery system incorporates a flexible distal portion that can navigate the tortuous venous sinus anatomy to reach the target location, while the proximal portion maintains sufficient rigidity to control and stabilize the stent during deployment. This local quality differentiation ensures both accurate positioning and reliable placement without causing incorrect positioning or lumen blockage.
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 solution enables effective scaffolding of the venous sinuses, minimizing the risk of re-collapse and stent jailing, while ensuring proper endothelium tissue growth and maintaining sinus patency, thus improving blood flow and reducing tissue damage.
Implementation Method 1
A self-expanding stent with varying flexibility and radial outward expansion strength from the distal to the proximal end, designed to match the venous sinus anatomy
Data Source
AI summary
A stent delivery system includes a shaft extending from a proximal end of the system into a delivery tip at a distal end. The shaft includes a coil and a stent bed. A stent is loaded onto the stent bed and has a first portion at its distal end having a greater flexibility than a second portion at its proximal end. Sheathing is moveable over the stent bed between pre-deployed and deployed positions. The sheathing includes a flexible section at the sheathing distal end, a semi-flexible section adjacent the flexible section, and a stiff section adjacent the semi-flexible section. The delivery tip is more flexible than the combination of the stent bed, the first portion of the stent, and the flexible section of the sheathing, which is more flexible than the combination of the stent bed, the second portion the stent, and the flexible section of the sheathing.