Stent Delivery Cover Positioning for Repositioning
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Solution Overview
Problem
Current methods for delivering intravascular stents to treat aneurysms face challenges in precision placement, as it is difficult to reposition or retract the stent once partially expanded within the vessel, leading to potential suboptimal initial landing and limited control over stent placement.
Innovation Solution
A medical device delivery system featuring a core member with a distal portion and a cover that transitions between positions to facilitate stent deployment, allowing for the stent to self-expand and decouple from the cover, enabling precise placement and potential retraction of the stent within the catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent is expanded at the treatment location using traditional methods, then the stent can be deployed to support the vessel, but it becomes very difficult or impossible to reposition, recapture, or retract the stent once partially expanded
Solution Approach 1:
The delivery system employs a dynamic mechanism where the stent transitions from a constrained compressed state during delivery to an expanded state at deployment. The system allows controlled transition between states, enabling the stent to be recaptured and repositioned by manipulating the delivery catheter and core member before full expansion occurs. This dynamic capability resolves the contradiction by providing both reliable placement (when expanded) and operational flexibility (when partially expanded).
Solution Approach 2:
The system performs preliminary actions by positioning the stent in a compressed state within the delivery catheter before reaching the treatment site. The stent remains constrained during navigation through tortuous vasculature, and only upon deliberate deployment does it expand. This preliminary constrained positioning allows for easy repositioning if needed before final deployment, resolving the contradiction between placement precision and repositioning capability.
2Manufacturing precision
If the stent is initially landed in a suboptimal location within the vessel using traditional methods, then the stent cannot be easily repositioned, but precise placement is critical for successful treatment
Solution Approach 1:
The system changes the physical state parameters of the stent during deployment. The stent transitions from a compressed low-profile state during delivery to an expanded state at deployment. This parameter change enables the operator to adjust the stent position by manipulating the delivery system before full expansion, providing both precision (when fully deployed) and flexibility (during the transition phase) to correct suboptimal landing positions.
3Strength
If the cover remains in the first position during stent expansion, then the stent is constrained, but the stent needs to expand to provide vessel support
Solution Approach 1:
The delivery system is segmented into distinct functional components: the delivery catheter, the core member, and the cover. The cover can be selectively positioned in different states (first position for constraint, second position for expansion). This segmentation allows independent control of each component, enabling the operator to manage the transition from constrained to expanded state while managing the complexity through modular design.
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 enhances the precision and control of stent placement, allowing for accurate positioning and potential retraction of the stent, reducing the risk of suboptimal placement and improving the success of vascular interventions.
Implementation Method 1
The stent can be expanded at the treatment location, often by allowing a first end of the stent to expand and thereafter slowly expanding the remainder of the stent
Data Source
AI summary
A stent delivery system can include a core member having a distal portion, where the distal portion is configured to be positioned within a lumen of the stent; a cover having a first end portion coupled to the distal portion of the core member and a free second end portion, the cover having (a) a first position in which the second end portion of the cover is configured to at least partially surround a proximal end portion of the stent while the stent is positioned over the core member in a compressed state, and (b) a second position in which the second end portion of the cover is uncoupled from the stent; and a shoulder coupled to the distal portion of the core member at a location distal to the first end portion of the cover, the shoulder configured to abut the proximal end portion of the stent.