Nitinol Y-Stent Delivery Catheter for Bronchial Junctions
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Solution Overview
Problem
Existing methods for restoring patency in collapsed bronchial airways, such as those caused by neoplastic occlusion or chronic mitral valve disease, often fail to effectively deploy stents at bronchial junctions due to material incompatibility and structural limitations, leading to erosion and mucociliary clearance issues.
Innovation Solution
The development of Y-stents made from braided or woven nitinol, which are collapsible and self-expanding, along with a delivery catheter system featuring guide wires and a plunger shaft, allows for precise placement and expansion of the stent at bronchial junctions, minimizing frictional forces and preventing dislodgement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stents are made from rigid materials to maintain structural strength, then the stent can provide adequate support, but the stent causes erosion of the airway and long term problems with mucociliary clearance
Solution Approach 1:
The patent changes the material parameters from rigid metals to flexible nitinol alloy, which has unique properties including shape memory and superelasticity. This allows the stent to maintain structural strength while being flexible and biocompatible, resolving the contradiction between strength and airway compatibility
Solution Approach 2:
The patent uses nitinol, a composite alloy of nickel and titanium, which combines the benefits of both metals to create a material that is both strong and flexible. This composite material provides the necessary structural support while being gentle on the airway tissue
2Ease of operation
If the distal end of the delivery catheter is obstructed by delivery system structures, then the stent can be controlled during deployment, but proximally directed forces are exerted on the stent during withdrawal causing potential dislodgement
Solution Approach 1:
The patent removes the obstructing structures from the distal end of the delivery catheter, creating an open distal end. This eliminates the source of harmful proximally directed forces while the stent deployment is still controlled by the plunger shaft and delivery catheter body
Solution Approach 2:
The patent introduces a plunger shaft as an intermediary mechanism to control stent deployment. The plunger shaft pushes the stent forward for deployment but does not obstruct the distal end, allowing controlled deployment without creating harmful forces during withdrawal
3Strength
If the Y-stent is made non-collapsible to maintain structural integrity, then the stent provides continuous support, but the stent cannot be compressed into the delivery catheter for minimally invasive placement
Solution Approach 1:
The patent makes the stent dynamic by using nitinol's shape memory and superelastic properties. The stent can be compressed into a small configuration for delivery, then automatically returns to its expanded functional shape at the deployment site, providing continuous support throughout the process
4Manufacturing precision
If the delivery catheter has an obstructed distal end to control stent deployment, then the stent can be precisely positioned, but frictional forces and proximally directed forces increase during withdrawal
Solution Approach 1:
The patent removes obstructing structures from the distal end of the delivery catheter, eliminating the source of excessive frictional and proximally directed forces. Precise placement is achieved through other means such as guide wires and delivery catheter 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 nitinol Y-stents effectively restore and maintain airway patency with reduced risk of erosion and mucociliary clearance issues, as they are biocompatible, flexible, and allow tissue ingrowth, while the delivery system ensures accurate positioning and expansion without proximally directed forces.
Implementation Method 1
the Y-stent has sufficient inherent shape memory so that when pushed from the delivery catheter the Y-stent takes its original desired shape
Implementation Method 2
the nitinol Y-stents effectively restore and maintain airway patency with reduced risk of erosion and mucociliary clearance issues, as they are biocompatible, flexible
Data Source
AI summary
Y-stents and delivery apparatus for delivering the Y-stents include a delivery catheter with an open distal end having two, circumferentially opposed extensions separated by two receiving portions which receive an anatomical junction.