Loading Mandrel Projections for Stent Buckling Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Long, flexible stent devices face the risk of axial damage or buckling during loading into a stent device delivery system due to uneven distribution of axial forces from frictional interactions with the crimping head and outer sheath, particularly in self-expanding stents that require radial expansion upon deployment.
Innovation Solution
A loading method using a loading mandrel with projections and recesses that deform the stent device, allowing for a form fit engagement along its inner surface to distribute axial forces uniformly, maintaining contact and frictional support even after expansion within the outer sheath, ensuring stable transfer and deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a loading mandrel is used to push the stent device into the outer sheath, then the stent device can be transferred into the outer sheath, but axial forces from frictional interactions cause uneven force distribution along the stent device, increasing the risk of buckling and axial damage
Solution Approach 1:
The loading mandrel is segmented with multiple projections spaced along its length, which engage with corresponding recesses in the stent device. This segmentation distributes the axial pushing force into multiple localized contact points along the stent device, preventing concentration of stress at a single point and thereby reducing the risk of buckling and axial damage during loading.
Solution Approach 2:
The loading mandrel features localized protrusions at specific positions along its length, creating corresponding localized engagement points with the stent device recesses. This local quality ensures that axial forces are applied at multiple distributed locations rather than uniformly, optimizing force distribution to match the stent device's structural characteristics and prevent buckling.
2Adaptability or versatility
If the stent device is made long and flexible to traverse tortuous vascular pathways, then it can navigate complex anatomy, but it becomes more susceptible to axial damage and buckling during loading
Solution Approach 1:
The loading mandrel's segmented design with multiple spaced projections provides distributed axial support along the entire length of the stent device. This segmentation is particularly beneficial for long, flexible stents, as it prevents buckling by creating multiple engagement points that collectively support the stent's flexibility while resisting axial compression forces during loading.
Solution Approach 2:
The loading mandrel is pre-configured with projections and recesses in specific geometric relationships before the loading procedure. This preliminary arrangement ensures that when the stent device is pushed into the outer sheath, the forces are automatically distributed in an optimal pattern that prevents buckling, allowing long and flexible stents to be loaded safely.
3Force
If frictional forces are increased between the loading mandrel and stent device to maintain engagement, then axial force transmission is improved, but the risk of axial damage and buckling increases due to uneven force distribution
Solution Approach 1:
The loading mandrel is divided into multiple projection elements that engage with recesses in the stent device at different locations. This segmentation distributes the axial force transmission across multiple contact points, allowing sufficient frictional engagement for effective force transmission while preventing concentration of stress at any single point, thereby reducing the risk of axial damage and buckling.
Solution Approach 2:
The loading mandrel features localized protrusions at specific positions along its length, creating corresponding localized engagement points with the stent device recesses. This local quality ensures that axial forces are applied at multiple distributed locations rather than uniformly, optimizing force distribution to match the stent device's structural characteristics and prevent buckling.
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
This method effectively reduces the risk of buckling and maintains structural integrity by distributing axial forces along the stent device's length, enabling successful traversal of tortuous vascular pathways and ensuring the stent expands correctly upon deployment.
Implementation Method 1
The stent device is subject to radially compressive forces in a crimping head to crimp the stent device into a radially collapsed configuration
Implementation Method 2
frictional interactions with the crimping head and outer sheath
Implementation Method 3
self-expanding stent devices that are so made that they automatically expand to the radially expanded configuration once given the radial freedom to do so
Data Source
AI summary
A method of moving a stent device into an outer sheath of a stent device delivery system is disclosed. The stent device is crimped into a collapsed configuration onto the loading mandrel. The loading mandrel is pushed toward the outer sheath as the engaging surfaces resist relative longitudinal movement between the stent device and the loading mandrel to move the stent device into the outer sheath. Upon entering the outer sheath, the stent device expands radially until radially constrained by the outer sheath.