Stent Delivery System Proximal Constraining Arrangement
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Solution Overview
Problem
Conventional stent delivery systems face challenges such as difficulty in repositioning or removing the stent after deployment, inaccurate placement due to sheath-related issues, and high force requirements, which can lead to stent malpositioning and increased complexity in deployment and retrieval.
Innovation Solution
A stent delivery system with an elongate shaft and constraining arrangements, including proximal and distal constraining members and a release wire, allows for controlled deployment and repositioning of the stent by applying axial mechanical force and enabling the stent to be moved between constrained and expanded configurations, facilitating precise placement and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sheathed delivery device is used to deploy a stent, then the stent can be delivered through the body lumen, but the device becomes difficult to reposition or remove and slow to operate once the stent is deployed
Solution Approach 1:
The patent removes the outer sheath entirely from the delivery system, extracting the constraining function to a separate proximal constraining arrangement that can be independently controlled. This allows the stent to be deployed without the sheath interference that causes repositioning difficulties, while maintaining deployment control through the proximal constraining mechanism.
Solution Approach 2:
The patent segments the constraining function from the delivery catheter by using a separate proximal constraining arrangement that can be independently manipulated. This segmentation allows the stent to be constrained during delivery but freely repositioned after deployment by simply adjusting the proximal constraining mechanism without affecting the entire delivery system.
2Manufacturing precision
If the outer sheath is proximally withdrawn to deploy the stent, then the stent expands, but accurate placement of the proximal portion of the stent becomes difficult
Solution Approach 1:
The patent introduces a proximal constraining arrangement as an intermediary mechanism between the operator and the stent. This proximal constrainer provides precise control over stent expansion and positioning by allowing incremental release of the constraining force, enabling accurate placement of the proximal stent portion without the jerky motion caused by sheath retraction.
3Reliability
If a sheathed delivery system is used, then the stent can be contained during delivery, but the sheath prevents or obscures direct visualization of the stent location
Solution Approach 1:
The patent extracts the containment function from an outer sheath to a proximal constraining arrangement. This removal eliminates the visual obstruction caused by the sheath while maintaining stent containment during delivery through the proximal constrainer, allowing direct visualization of the stent location throughout the delivery and deployment process.
4Reliability
If a conventional sheathed stent delivery system is used, then the stent can be delivered, but high force is required to overcome friction between the stent and sheath
Solution Approach 1:
The patent removes the outer sheath that creates friction against the stent, eliminating the high force requirements. The stent is delivered without sheath contact, and only the low-friction proximal constraining arrangement remains to provide containment and controlled deployment.
5Reliability
If the stent is fully deployed before repositioning attempts, then the stent is radially expanded, but the sheath cannot reconstrain the stent for repositioning
Solution Approach 1:
The patent uses a dynamic proximal constraining arrangement that can be adjusted after stent deployment. The proximal constrainer can be manipulated to reconstrain the stent even after radial expansion, allowing repositioning by simply adjusting the proximal constraining mechanism without requiring the stent to be fully committed to its final position.
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 enhances control and accuracy in stent placement, reduces the risk of malpositioning, and allows for smoother, quicker deployment and retrieval, addressing the limitations of conventional sheathed systems.
Implementation Method 1
A proximal constraining arrangement is engaged with a proximal end of the stent... A distal constraining arrangement is engaged with a distal end of the stent
Implementation Method 2
Conventional sheathed stent delivery devices also require a high force to overcome the friction between the stent and the sheath
Data Source
AI summary
A stent delivery system includes an elongate shaft including a proximal portion, a distal portion, at least one lumen extending at least partially therethrough, and a stent receiving portion on the distal portion of the elongate shaft. A stent is positioned on the stent receiving portion of the elongate shaft, the stent having a first configuration and a second configuration. A proximal constraining arrangement is engaged with a proximal end of the stent. A distal constraining arrangement is engaged with a distal end of the stent. A release wire is disposed through the elongate shaft and releasably engaged with portion of the proximal constraining arrangement and the distal constraining arrangement member. A handle assembly is operably connected to the proximal constraining arrangement and the distal constraining arrangement, the handle assembly comprising a brake assembly. The proximal arrangement and the distal arrangement are coupled to the brake of the handle.