Stent Delivery System Collapsible Frame Friction Reduction
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Solution Overview
Problem
Loading large diameter stents into stent delivery systems often results in increased friction forces between the stent and the exterior sheath, making it difficult to manage, especially when using larger stents in medical procedures.
Innovation Solution
A stent delivery system with a collapsible frame that radially collapses over the stent using an actuation member, such as a pull wire, to minimize friction and facilitate loading, allowing the stent to be expanded or collapsed from an expanded configuration to a collapsed configuration for delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an exterior sheath is slid overtop the stent during loading, then the stent can be contained and delivered, but friction forces between the stent and exterior sheath increase significantly
Solution Approach 1:
Instead of sliding the exterior sheath over the stent in the conventional manner, the patent inverts the approach by having the stent pushed through the exterior sheath from the distal end. This reversal of the loading direction eliminates the rubbing friction that occurs when the sheath is pulled over the stent, significantly reducing friction forces during loading.
2Adaptability or versatility
If large diameter stents are used, then they can effectively support large body lumens, but friction forces during loading increase making them difficult to manage
Solution Approach 1:
The patent applies the inversion principle specifically to large diameter stents by reversing the loading sequence. Rather than attempting to pull the exterior sheath over the large stent (which creates excessive friction), the stent is pushed through the sheath from the distal end, making large diameter stents manageable and easy to load despite their size.
3Length of moving object
If the stent is kept in collapsed configuration during delivery, then it can be delivered through catheters, but friction forces increase when using conventional loading methods
Solution Approach 1:
The patent resolves the friction problem during collapsed stent delivery by inverting the loading method. The stent is loaded in collapsed configuration by pushing it through the exterior sheath from the distal end rather than pulling the sheath over the stent, thereby maintaining the space-constrained delivery requirement while minimizing friction forces throughout the delivery process.
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 reduces friction forces during stent loading and deployment, enabling the efficient placement of large diameter stents in body lumens by maintaining the stent in a collapsed configuration during delivery and allowing it to expand naturally upon deployment, thus supporting the lumen effectively.
Implementation Method 1
this process may result in increased friction forces between the stent and the exterior sheath
Data Source
AI summary
A stent delivery device including an elongate shaft having a proximal region, a distal region and at least one lumen extending therein. The stent delivery device also includes a collapsible frame attached to the distal region of the elongate shaft. The collapsible frame includes a plurality of arms configured to surround a stent such that the plurality of arms define a stent containment region. The stent delivery device also includes an inner member extending within a least a portion of the stent containment region and an actuation member configured to actuate the plurality of arms of the collapsible frame from an expanded configuration to a collapsed configuration.