Segmented Suture Stent Deployment System
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Solution Overview
Problem
Current self-expanding stent delivery systems using outer sheaths require high deployment force, leading to positioning difficulties and potential damage to body lumens, and result in inaccurate stent placement due to sequential expansion from distal to proximal ends, with high frictional forces during withdrawal.
Innovation Solution
A stent delivery system employing individual suture loops along the stent's longitudinal length, secured by a longitudinal pull member, which separates from the stent upon removal, allowing for controlled expansion and reduced deployment force, and optionally using multiple pull members for precise deployment control and a retrieval member for suture loop removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an outer sheath is used to compress and deliver the self-expanding stent, then the stent can be delivered through the body lumen, but high deployment force is required to remove the outer sheath which causes positioning difficulties and potential damage to the body lumen
Solution Approach 1:
The outer sheath is divided into multiple segmented sheaths that can be independently removed. This segmentation reduces the deployment force required at any single moment and allows for more controlled, incremental stent expansion, thereby improving positioning accuracy while reducing the risk of body lumen damage
Solution Approach 2:
The stent is pre-compressed within the segmented sheath structure before delivery. The sheath segments are designed to separate in a controlled sequence, allowing the stent to gradually expand to its final configuration. This preliminary compression and controlled release mechanism reduces the peak deployment force needed while maintaining positioning precision
2Ease of operation
If the outer sheath is pulled from distal to proximal end to expand the stent, then the stent deploys, but the distal end expands first and proximal end last resulting in inaccurate stent placement
Solution Approach 1:
The sheath is segmented into multiple sections that can be removed independently or in controlled sequences. This allows the stent to expand in a more uniform manner across its length, rather than sequentially from distal to proximal end, thereby improving both placement accuracy and expansion uniformity
Solution Approach 2:
Instead of pulling the sheath from distal to proximal end (sequential expansion), the segmented sheath design allows for simultaneous or reverse-sequenced removal, enabling the proximal end to expand first or in parallel with the distal end, thus achieving more uniform expansion and accurate placement
3Volume of moving object
If the stent is compressed to a smaller diameter using an outer sheath, then delivery through the body lumen is enabled, but greater deployment force is required which may damage the stent
Solution Approach 1:
The compression force is distributed across multiple sheath segments rather than a single continuous sheath. During deployment, each segment can be removed independently, distributing the expansion force over time and reducing peak stresses on the stent structure, thereby preventing stent damage while maintaining compact delivery dimensions
Solution Approach 2:
The sheath segments are designed with dynamic release characteristics, allowing controlled separation during stent expansion. This dynamic release mechanism ensures that the stent expands gradually rather than suddenly, preventing structural damage while achieving the required compression for delivery through the body lumen
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 enables lower profile delivery, reduced deployment force, and more precise stent placement with lower trauma to the body lumen, while allowing biodegradable suture loops to safely dissolve or be absorbed, and facilitating controlled deployment and retrieval.
Implementation Method 1
Self-expanding stents are often made of a wire or mesh material that can elastically contract and expand
Implementation Method 2
The self-expanding stent is compressed using an outer sheath: a simple tubular structure with a lumen running through it
Implementation Method 3
Once in the deployed state, the self-expanding stent is secured to the walls of the body lumen through friction
Data Source
Figure 1~2
Figure 3A~4
Figure 5~6
AI summary
A stent delivery system is provided that includes a self-expanding stent with a longitudinal length and a plurality of individual suture loops spaced along the longitudinal length of the stent, wherein the stent is compressed by the plurality of individual suture loops. The stent delivery system also includes a longitudinal pull member that secures the plurality of individual suture loops about the stent, wherein the plurality of individual suture loops are configured to separate from about the stent when the longitudinal pull wire is removed.