Stent Delivery System Proximal Release Assembly
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Solution Overview
Problem
Current aortic stent delivery systems lack accurate deployment control, often requiring open surgery for stent removal when improperly deployed, due to self-expansion issues after outer sheath retrieval.
Innovation Solution
A second release assembly is introduced at the proximal end of the delivery system, allowing for incomplete deployment of the stent with its proximal end still restrained, enabling fine adjustments for precise positioning before complete expansion, utilizing a proximal fixing part, restrain part, and control guidewire configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a simple covered stent deployment method involving retrieval of an outer sheath is used, then the stent can self-expand, but deployment control accuracy deteriorates
Solution Approach 1:
The release assembly is divided into multiple independent components: an outer sheath for initial stent containment, an inner sheath for selective proximal end containment, and a control mechanism with pull wires. This segmentation allows independent control of stent expansion at different locations, enabling the distal end to expand first while the proximal end remains restrained, thus improving deployment control accuracy without sacrificing operational simplicity
Solution Approach 2:
The delivery system is pre-configured with the inner sheath positioned to restrain the proximal end of the stent before deployment. The control mechanism is pre-assembled with pull wires attached to the inner sheath, allowing the operator to selectively release the proximal end at the desired moment. This preliminary arrangement enables precise control over the timing and sequence of stent expansion, resolving the contradiction between simple operation and deployment accuracy
2Manufacturing precision
If the stent is improperly located and self-expands immediately, then deployment control is lost, but open surgery with high fatality is required for removal
Solution Approach 1:
The release assembly employs dynamic, movable components including the inner sheath that can slide relative to the outer sheath, and pull wires that can be tensioned or relaxed. This dynamic configuration allows the operator to adjust the restraint on the stent's proximal end in real-time during deployment, enabling correction of positioning errors and preventing uncontrolled self-expansion, thus improving positioning accuracy without requiring overly complex fixed mechanisms
Solution Approach 2:
The inner sheath acts as an intermediary component between the operator's control inputs and the stent's proximal end. By manipulating the inner sheath through the control mechanism, the operator can indirectly control the release of the proximal end, providing a buffer that enhances positioning precision and prevents premature expansion, thereby reducing the need for corrective open surgery
3Manufacturing precision
If the proximal end of the stent is restrained after outer sheath retrieval, then fine adjustments can be made for accurate deployment, but the device structure becomes more complex
Solution Approach 1:
The inner sheath serves multiple functions: it contains the proximal end of the stent during delivery, provides a surface for the stent to expand against when released, and acts as a control element for selective proximal end deployment. This multi-functionality reduces the need for additional specialized components, allowing the system to achieve enhanced deployment precision without proportionally increasing structural complexity
Solution Approach 2:
The inner sheath is nested within the outer sheath, with both components having hollow interiors that accommodate the stent during delivery. This nested configuration allows the proximal end restraint mechanism to be integrated within the existing delivery system structure, adding the necessary complexity for precise control while minimizing the increase in overall device complexity through space-efficient design
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
This design enables delayed and more accurate deployment of the stent, reducing the need for open surgery by allowing precise adjustment and complete expansion only when the stent is accurately positioned.
Implementation Method 1
retrieval of an outer sheath which allows the stent to expand by itself due to its elasticity
Data Source
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AI summary
A stent delivery system and a second release assembly are disclosed. The second release assembly is configured to control the deployment of a proximal end of a vascular stent and is disposed at a proximal end of the delivery system. The second release assembly includes, sequentially from a proximal end (P) to a distal end (D), a proximal fixing part (1), a restrain part (3) and a control guidewire (5). The restrain part is detachably connected to the proximal fixing part (1) at one end and is coupled to the control guidewire (5) at the other end. With the second release assembly, accurately controlled deployment of the vascular stent is achievable by deploying the proximal end of the vascular stent after the vascular stent has been accurately located.