Interventional Delivery System Sheath Segmentation for Retrieval
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Solution Overview
Problem
Current delivery systems for interventional devices face challenges in accurately positioning and retrieving support frames during procedures like aortic and pulmonary valve replacements, leading to potential valve displacement, mispositioning, and increased surgical risks due to limited constraint force and compliance issues.
Innovation Solution
A delivery system featuring a sheath surrounded by an axially movable tube that transitions from an initial to an operation configuration, providing enhanced strength and anti-expansion performance to securely hold and retrieve the interventional device, preventing it from falling out and allowing for precise repositioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the strength of the sheath is increased to prevent the interventional device from falling out, then the constraint force is improved, but the compliance of the sheath is reduced which results in inconvenience for the interventional operation
Solution Approach 1:
The sheath is divided into two functional sections: a carrier section with higher strength to constrain the support frame and prevent it from falling out, and a pusher section with lower strength to maintain compliance for smooth delivery. This segmentation allows each section to have optimized properties for its specific function, resolving the contradiction between constraint force and compliance.
Solution Approach 2:
Different sections of the sheath are assigned different mechanical properties: the carrier section has increased wall thickness and strength to provide constraint force, while the pusher section maintains thinner walls and higher compliance for ease of operation. This local differentiation of properties allows the sheath to simultaneously satisfy both requirements in different locations.
2Reliability
If the sheath is made stronger to retrieve the support frame, then the reliability is improved, but the device complexity increases due to the need for multiple sections with different properties
Solution Approach 1:
The sheath is segmented into a carrier section and a pusher section, where the carrier section is designed with higher strength to reliably retrieve the support frame. This segmentation improves retrieval success rate while keeping the overall structure relatively simple by only dividing the sheath into two functional parts rather than using complex mechanisms.
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 effectively reduces the risk of surgical complications and mortality by ensuring accurate positioning and retrieval of the support frame, enhancing the success rate of interventional operations while maintaining compliance for smooth operation.
Implementation Method 1
the tube can assume an initial configuration in which a proximal end portion of the tube is located at an outer periphery of the pusher section and an operation configuration in which the proximal end portion of the tube is held tightly around the carrier section
Data Source
AI summary
A delivery system facilitating retrieval of interventional device includes a sheath, an operation handle for driving the sheath to move, and a tube axially slidably engaging with the pusher section. The sheath includes a carrier section at a proximal end for surrounding the interventional device and a pusher section connected with the carrier section. Depending on different axial positions, the tube assumes an initial configuration in which a proximal end portion thereof is at a periphery of the pusher section, and an operation configuration in which the proximal end portion is held tightly around the carrier section and limits further expansion of the carrier section. The delivery system functions to hold the support frame tightly by surrounding the sheath with the axially movable tube, retrieving the support frame and preventing the support frame from falling off from a core shaft, thereby reducing risks in surgery and the mortality rate. The tube may be manually driven or driven in other ways, which is convenient to coordinate with known control handles or sheaths.