Retractable Catheter Sleeve for Vascular Gap Minimization
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Solution Overview
Problem
Existing catheter-based delivery systems face challenges in minimizing the gap between semi-rigid compacted medical devices and soft flexible tips, leading to potential vascular trauma and maneuverability issues during deployment.
Innovation Solution
A catheter system incorporating a flexible, tubular restraining member with a retractable section that extends over both the compacted device and the catheter tip to bridge the gap, which retracts as the device expands, using an elastomeric material and a tensioned stitch line to maintain the restraining member in a stretched state until release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rigid catheter is used to constrain the device into a small profile and cover the gap, then the gap between the device and catheter tip is covered, but the device becomes stiffer and more difficult to bend into a small radius
Solution Approach 1:
The catheter shaft is divided into multiple sections with different stiffness characteristics. The proximal portion has a larger outer diameter and greater stiffness, while the distal portion has a smaller outer diameter and lesser stiffness, allowing the catheter to be maneuverable yet provide gap coverage when needed
Solution Approach 2:
Different sections of the catheter shaft are assigned different mechanical properties locally. The proximal section provides structural support and gap coverage, while the distal section provides flexibility for navigation, allowing each part to optimize its function without compromising the whole system
2Ease of operation
If the catheter is made more flexible to improve maneuverability through curved vessels, then ease of navigation increases, but the ability to maintain a small profile and constrain the device effectively decreases
Solution Approach 1:
The catheter is segmented into proximal and distal portions with different stiffness properties, allowing the distal portion to be flexible for navigation while the proximal portion maintains sufficient stiffness for device constraint and gap coverage
Solution Approach 2:
The catheter's effective stiffness is dynamically adjusted through its segmented design, where the flexibility varies along its length to provide maneuverability at the tip while maintaining structural integrity and constraining capability at the proximal section
3Object-affected harmful factors
If a soft flexible tip is positioned distal to the compacted device to minimize vascular trauma, then vascular trauma is reduced, but a gap opens up between the stiff device and soft tip during advancement through curved vessels
Solution Approach 1:
The proximal portion of the catheter shaft acts as an intermediary element between the compacted device and the distal tip, providing structural support to bridge the gap that forms during advancement through curved vessels while allowing the soft tip to continue minimizing vascular trauma
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
Effectively minimizes the gap between the device and the catheter tip, allowing for smoother navigation through curved vessels and ensuring accurate positioning by maintaining the restraining member in a tensioned state until the device is fully expanded, reducing vascular trauma and enhancing deployment accuracy.
Implementation Method 1
The retractable section can be made from an elastomeric material and stretched such that the retractable section is releasably maintained in a tensioned state
Data Source
Figure 1
Figure 2
Figure 2a
AI summary
A medical device constraint includes an elastic element having proximal and distal ends, a continuous lumen extending between the proximal and distal ends of the tubular elastic element; and a medical device disposed at least partially within the continuous lumen, wherein the generally tubular element has a first state in which the tubular element is longitudinally held in tension to conceal a gap between the medical device and a distal tip and a second state in which the tubular element is longitudinally relaxed and spaced apart from the gap.