Nested Tube Endoprosthesis Delivery Device for Long Stents
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Solution Overview
Problem
Existing endoprosthesis delivery devices face challenges in efficiently loading and accurately deploying long endoprostheses due to complexity and difficulty in handling, particularly with polymeric or plastic self-expanding stents, which require elongation and precise placement at desired locations within body lumens.
Innovation Solution
A delivery device comprising nested concentric tubes with retaining mechanisms at both ends of the endoprosthesis, allowing for controlled displacement and release of the endoprosthesis ends to facilitate accurate placement and expansion within the body lumen, enabling the deployment of endoprostheses up to 60 centimeters or longer with reduced radial force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional delivery device is used to deliver a long endoprosthesis (30 cm or greater), then the endoprosthesis can be delivered, but the device becomes excessively long or requires high delivery force
Solution Approach 1:
The delivery device employs a nested tube configuration where an inner tube is disposed within a middle tube lumen, and the middle tube is disposed within an outer tube lumen. This nesting arrangement allows the delivery device to maintain a compact overall length while accommodating a long endoprosthesis (30 cm or greater) through the concentric tube structure, eliminating the need for an excessively long delivery device.
2Length of moving object
If a conventional delivery device is used to deliver a long endoprosthesis, then the endoprosthesis can be delivered, but high delivery force is required
Solution Approach 1:
The nested tube configuration (inner tube within middle tube within outer tube) distributes the structural support load across multiple concentric elements rather than requiring a single long rigid structure. This reduces the delivery force needed to push the long endoprosthesis through the delivery device, as each tube segment contributes to load bearing and the nested structure provides mechanical advantage.
Solution Approach 2:
The delivery device is segmented into multiple functional tube components (inner tube, middle tube, outer tube) with retaining mechanisms at different locations. This segmentation allows the long endoprosthesis to be supported and delivered in a controlled manner, reducing the peak delivery force required compared to a conventional single-tube design.
3Ease of manufacture
If the endoprosthesis is elongated during loading, then it can be loaded on the delivery device, but accurate delivery at the desired location becomes difficult
Solution Approach 1:
The nested tube structure provides a stable, organized pathway for the endoprosthesis during loading and delivery. The concentric arrangement of inner, middle, and outer tubes with retaining mechanisms ensures that the endoprosthesis maintains its position and orientation, preventing displacement or misalignment that would occur with elongation, thereby enabling accurate delivery at the desired location.
Solution Approach 2:
The retaining mechanisms are pre-positioned on the nested tubes to engage with the endoprosthesis ends before delivery. This preliminary securing action prevents the endoprosthesis from shifting or elongating during the delivery process, ensuring accurate placement at the target location while still allowing easy loading.
4Ease of operation
If retaining mechanisms are added to both ends of the endoprosthesis, then loading and deployment is simplified, but device complexity increases
Solution Approach 1:
The retaining mechanisms are integrated into the nested tube structure itself, combining the functions of the delivery device tubes with the retention function. The inner tube distal end region includes a first retaining mechanism, and the outer tube distal end region includes a second retaining mechanism, merging structural support and retention functions into a unified design that simplifies operation without proportionally increasing complexity.
Solution Approach 2:
The nested tubes serve multiple functions: they provide structural support for the long endoprosthesis, guide its delivery, and incorporate retaining mechanisms for securing and releasing the endoprosthesis ends. This multi-functionality reduces the need for separate dedicated retention components, balancing ease of operation with device complexity.
Data Source
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Figure 3A
AI summary
An delivery device (100) including an inner tube (110) having an inner tube proximal end region (112) and an inner tube distal end region (114), the inner tube distal end region comprising a first retaining mechanism; a middle tube (120) having a middle tube distal end region (122) and a middle tube proximal end region (124) and defining a middle tube lumen, the inner tube disposed within the middle tube lumen; and an outer tube (130) having an outer tube proximal end region (132) and an outer tube distal end region (134) and defining an outer tube lumen, the middle tube disposed within the outer tube lumen, the outer tube distal end region comprising a second retaining mechanism; wherein the inner tube is structured and arranged to displace proximally and distally relative to the middle tube, and wherein the outer tube is structured and arranged to displace proximally and distally relative to the middle tube. A method of deploying an endoprosthesis is also disclosed.