Stent Delivery System with Spiral-Cut Flex Zones for Repositioning
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Solution Overview
Problem
Conventional methods for delivering intravascular stents to treat aneurysms often result in suboptimal placement, as it is difficult to reposition the stent within the vessel once it has been partially expanded.
Innovation Solution
A stent delivery system featuring a core member with an elongate, spiral-cut tube that has distinct flex zones and transition zones, allowing for precise navigation and potential repositioning of the stent within the vasculature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional stent delivery methods are used, then the stent can be delivered to the treatment site, but the stent cannot be repositioned once partially expanded
Solution Approach 1:
The delivery system employs a dynamic mechanism where the stent can be recaptured and repositioned before final deployment. The system transitions from a static deployed state to a dynamic recapturable state, allowing the stent to be moved along the delivery catheter if suboptimally positioned, thereby resolving the contradiction between ease of repositioning and placement reliability
2Manufacturing precision
If the stent is expanded to support the vessel wall, then vessel support is achieved, but the stent cannot be moved to optimal position
Solution Approach 1:
The system performs preliminary positioning actions before final stent expansion. The stent is first delivered to the approximate treatment site in a compressed state, allowing for position adjustment, and only after optimal positioning is achieved is the stent expanded to provide vessel support, thus resolving the contradiction between placement precision and vessel support
3Ease of operation
If the stent is fully expanded immediately, then vessel support is provided, but the ability to correct placement errors is lost
Solution Approach 1:
The delivery system maintains a dynamic state where the stent can be recaptured and repositioned for a limited time after initial deployment. This temporary adjustability window allows correction of placement errors without significantly impacting treatment efficiency, as the stent can be quickly repositioned and redeployed if needed
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 system enables precise placement and potential repositioning of the stent, ensuring optimal support for the vessel wall and minimizing the risk of stent misplacement.
Implementation Method 1
an elongate, spiral-cut tube extending proximally of the intermediate portion, the tube having first and second flex zones, the second flex zone being proximal of the first flex zone, and a transition zone between the first and second flex zones; the first flex zone having a bending stiffness of less than 12 N*mm^2 so as to be navigable through the internal carotid artery bifurcation
Data Source
AI summary
A stent delivery system can include a core member, an introducer sheath, and a microcatheter. The core member can have a distal segment. The stent engagement member can have a generally tubular body positioned about the core member distal segment and can be rotatably coupled to the core member. The engagement member can include an inner layer that has a first durometer and an outer layer that has a second durometer less than the first durometer. The stent can extend along the core member distal segment such that an inner surface of the stent is engaged by the engagement member outer layer for facilitating rotation of the stent relative to the core member.