Lobed Biliary Stent with Creases for Drainage
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Solution Overview
Problem
Conventional biliary stents, especially expandable ones, face issues with clogging due to their smooth cylindrical shape, which limits their expansion and drainage capabilities during endoscopic deployment.
Innovation Solution
A biliary stent design featuring alternating lobes with creases that can expand mechanically, forming exterior channels for drainage, and a delivery device with retractable wings to facilitate easy expansion within the bile duct.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a smooth cylindrical stent shape is used, then the stent can be easily delivered through the endoscopic device channel, but the stent quickly becomes clogged due to limited drainage capability
Solution Approach 1:
The stent is segmented into multiple lobes separated by creases, transforming the smooth cylindrical surface into a multi-lobed structure. This segmentation creates exterior channels between adjacent lobes that enable effective drainage and prevent clogging, while the lobes can still be compressed into a compact form for delivery through endoscopic channels.
Solution Approach 2:
The invention adds a radial dimension to the stent structure by creating lobes that extend outward from the central axis. This dimensional change transforms the traditional two-dimensional cylindrical surface into a three-dimensional multi-lobed structure with exterior drainage channels, enabling improved drainage capability without compromising deliverability.
2Reliability
If an expandable stent design is used, then the stent can provide better drainage, but the expansion mechanism becomes complex and difficult to deploy
Solution Approach 1:
The stent employs a dynamic expansion mechanism where lobes transition from a compressed state during delivery to an expanded state after deployment. The creases between lobes act as hinges that facilitate this dynamic transformation, allowing the stent to expand radially outward to create exterior drainage channels without requiring complex mechanical components.
Solution Approach 2:
The invention replaces complex mechanical expansion systems with a simpler structure-based expansion mechanism. The lobed geometry itself, with creases acting as natural hinges, provides the expansion capability without requiring additional mechanical components, reducing device complexity while maintaining expandability.
3Reliability
If the stent is made with a larger cross-sectional diameter, then drainage capability improves, but the stent cannot be delivered through standard endoscopic device channels
Solution Approach 1:
The stent employs a nested configuration where the lobes are compressed inward against the central axis during delivery, allowing the stent to fit within the limited diameter of endoscopic device channels. After deployment, the lobes expand outward from this nested state to achieve the larger cross-sectional diameter needed for effective drainage, combining small deliverable size with large functional size.
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 stent design allows for effective expansion and enhanced drainage by creating exterior channels, reducing clogging and improving the stent's functionality and longevity within the bile duct.
Implementation Method 1
each of the plurality of lobes has a first contracted position biased inwards from the creases such that the biliary stent has a first cross-sectional diameter; and wherein each of the plurality of lobes has a second expanded position biased outwards from the creases
Data Source
AI summary
Devices, systems, and methods for deploying a biliary stent. A biliary stent has lobes and creases to expand between contracted and expanded positions. The stent is delivered to a bile duct in a contracted position loaded on a shaft of a delivery device. When the shaft is retracted through the stent, wings on the shaft force the stent outward into the larger expanded position. In the expanded position, the creases form drainage channels to reduce blockage over the life of the stent.