Atraumatic Delivery System for Stent Deployment
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Solution Overview
Problem
The deployment of self-expanding metal stents in anatomical areas with limited distal space is hindered by the elongated profile of the stent when loaded on the delivery system, leading to improper alignment, kinking, or perforation due to insufficient space for the distal flange.
Innovation Solution
A delivery system comprising a flexible elongate member and an inner member, where the stent is constrained between them, allowing the inner member to transition from a longer to a shorter length upon deployment, with a handle to control the extension and retraction, and a shape-memory distal portion to minimize contact with anatomical obstructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the stent is loaded onto the delivery system in a conventional elongated configuration, then the stent can be delivered through the body lumen, but the stent cannot be properly deployed in anatomical areas with limited distal space due to insufficient head space
Solution Approach 1:
The distal portion of the inner member is nested within loops formed by the stent's distal flange in the deployed configuration. This nesting allows the inner member to be contained within the stent structure itself, enabling the stent to foreshorten upon deployment without requiring excessive distal space beyond the delivery system.
Solution Approach 2:
The inner member transitions from a first length in the constrained configuration to a second, shorter length in the deployed configuration. This dynamic length change allows the delivery system to accommodate the stent's foreshortening during deployment, enabling proper positioning in anatomical areas with limited distal space.
2Strength
If the delivery system is made rigid to maintain structural integrity during delivery, then the system can withstand delivery forces, but the system cannot navigate anatomical obstructions or conform to curved pathways
Solution Approach 1:
The inner member has different flexibility characteristics at different portions: the distal portion is more flexible to navigate obstructions and curved pathways, while the proximal portion maintains sufficient rigidity to transmit delivery forces and maintain structural integrity during the delivery process.
Solution Approach 2:
The inner member is divided into functional segments with different mechanical properties - a distal portion designed for flexibility and navigation, and a proximal portion designed for strength and force transmission. This segmentation allows each portion to optimize its function while working together as a unified delivery system.
3Stability of the object's composition
If the distal portion of the inner member remains at the first length during deployment, then the stent can be constrained properly, but the delivery system will kink or bend and cause improper alignment or perforation in confined spaces
Solution Approach 1:
The distal portion of the inner member is pre-configured with loops that will form upon deployment. These pre-formed loops allow the inner member to automatically shorten to the second length when the stent is deployed, preventing kinking and perforation before they can occur.
Solution Approach 2:
The inner member undergoes a parameter change in length from the first length to the second length during stent deployment. This parameter change is coordinated with the stent's expansion, allowing the system to maintain stability during constraint while avoiding harmful kinking in the deployed configuration.
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
Enables proper deployment of the stent flange without kinking or perforation, maintaining structural integrity and ensuring accurate positioning within confined anatomical spaces.
Implementation Method 1
The distal portion of the inner member may be formed of a shape-memory material
Data Source
AI summary
The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to delivery systems configured to position a distal portion of a medical device within a restricted anatomical area. In one example, a delivery system may include a flexible elongate member with an inner member within a lumen of the flexible elongate member. A stent may be constrained therebetween. The stent may be configured to move between a first configuration to a second deployed configuration when unconstrained from the flexible elongate member. When the stent moves from the first configuration to the second configuration, the inner member may change from a first length to a second, shorter length. Other embodiments are contemplated.