Expandable-Mouth Catheter Introducer for Low-Force Sheath Insertion
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Solution Overview
Problem
Existing catheters with expandable members face difficulty in being introduced into delivery sheaths due to friction and deformation, especially in tapered sections, requiring excessive pushing force and hindering advancement.
Innovation Solution
The introducer tool features a variable-diameter distal portion that collapses radially inward when contacting the delivery sheath's tapered interior, reducing friction and allowing deeper insertion, thus facilitating the introduction of the catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a catheter with an expandable member is introduced into a delivery sheath with a tapered section, then the catheter can be delivered to the target site, but excessive pushing force is required and the catheter may deform
Solution Approach 1:
The introducer tool incorporates a collapsible distal portion with axial extensions that can flex and collapse radially inward. This flexible structure allows the distal portion to compress against the tapered interior surface of the delivery sheath, reducing friction and enabling easier catheter introduction without requiring excessive pushing force.
Solution Approach 2:
The distal portion of the introducer tool is designed to dynamically change its configuration from an expanded state to a collapsed state as it engages with the tapered section of the delivery sheath. This dynamic adaptation allows the introducer to navigate the tapered section smoothly, reducing the force required to advance the catheter.
2Strength
If the distal portion of the introducer tool is rigid, then structural strength is maintained, but the tool cannot advance farther into the tapered portion of the delivery sheath
Solution Approach 1:
The distal portion of the introducer tool is segmented into multiple axial extensions that can collapse independently. This segmentation allows the structure to maintain overall strength while enabling localized compression against the tapered sheath surface, facilitating deeper insertion without compromising structural integrity.
Solution Approach 2:
The axial extensions of the distal portion are designed to collapse and nest within each other when engaged with the tapered delivery sheath. This nested configuration allows the introducer tool to advance farther into the tapered portion while maintaining structural strength through the interconnected extension design.
3Object-affected harmful factors
If the distal portion collapses radially inward, then friction is reduced and insertion depth increases, but the pushing force required to collapse the structure must be applied
Solution Approach 1:
The design converts the harmful friction force into a beneficial collapsing force. As the introducer tool is pushed forward, the friction against the tapered sheath surface actually helps to collapse the distal portion radially inward, rather than resisting the motion. This eliminates the need for separate collapsing mechanisms and reduces the overall force required.
Solution Approach 2:
The distal portion is designed to collapse automatically through the friction force generated during insertion. The friction between the collapsed distal portion and the tapered sheath surface provides the necessary force to maintain the collapsed state, eliminating the need for additional collapsing mechanisms or excessive pushing force.
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 reduces the pushing force required to introduce the catheter into the sheath, enhancing navigability and reducing deformation, thereby improving thrombus engagement and aspiration efficiency.
Implementation Method 1
a distal tool portion of the introducer tool configured to collapse or compress radially inward to reduce an outer profile of the distal tool portion
Implementation Method 2
The beveled exterior surface may help the distal tool portion to conform to the tapered interior surface of the delivery sheath as the distal tool portion collapses radially inward
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A medical assembly 10 includes an expandable-mouth catheter 12 and an introducer tool 14 configured to facilitate advancement of the catheter into a delivery sheath 16. In some examples, a distal-most portion of the introducer tool includes a plurality of axial extensions (38A, 38B) separated by triangular-shaped slits. When the catheter is received within the introducer tool and when the introducer tool is received within a tapered portion of the delivery sheath, the axial extensions are configured to collapse radially inward to radially compress the expandable member and to enable the introducer to extend farther into the delivery sheath.