Expandable Introducer Sheath with Elastomeric Outer Layer
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Solution Overview
Problem
Existing expandable introducer sheaths for medical procedures face issues such as vessel trauma and high insertion forces due to protruding edges and require additional steps for expansion, particularly with larger profile devices.
Innovation Solution
An introducer sheath with an inner shape-memory folded layer and an outer elastomeric layer that expands atraumatically to accommodate large profile devices and then collapses back to its original profile, minimizing vessel trauma and reducing insertion forces through the elastomeric layer's compressive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an expandable introducer sheath with a longitudinal slit is used to reduce profile, then the introducer can be inserted into smaller vessels, but protruding edges cause vessel trauma
Solution Approach 1:
The introducer sheath is constructed as a flexible, thin-walled structure that can be collapsed to a low profile for insertion and then expanded to accommodate large profile devices. The flexibility of the thin film structure allows it to deform without creating sharp protruding edges that would cause vessel trauma.
Solution Approach 2:
The introducer sheath transitions from a collapsed state during insertion to an expanded state during device passage. This dynamic transformation allows the sheath to adapt its profile - small during insertion to access vessels, then large enough to accommodate big profile devices, eliminating the need for protruding edges.
2Adaptability or versatility
If force is applied to expand the introducer sheath, then large profile devices can pass through, but insertion forces become excessively high
Solution Approach 1:
The flexible thin-walled construction of the introducer sheath allows it to expand with minimal force. The material properties and structural design enable the sheath to deform and expand smoothly as devices are passed through, avoiding the high forces that would be required with rigid structures.
Solution Approach 2:
The introducer sheath changes its physical parameters - specifically its diameter and cross-sectional area - as devices are passed through. The sheath transitions from a collapsed low-profile state to an expanded high-profile state, allowing accommodation of large devices without requiring excessive expansion forces.
3Adaptability or versatility
If commercially available expandable introducers are used, then large profile devices can be accommodated, but additional expansion steps and prolonged balloon inflation are required
Solution Approach 1:
The introducer sheath is designed to expand and contract automatically in response to the passage of devices through its lumen. The sheath self-adjusts its profile without requiring external balloons, inflation mechanisms, or additional expansion steps, thereby reducing procedure time and complexity.
Solution Approach 2:
The introducer sheath dynamically adjusts its profile in real-time as devices are passed through. The sheath transitions between collapsed and expanded states automatically based on the presence and size of devices, eliminating the need for staged expansion procedures and prolonged balloon inflation.
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 solution enables atraumatic expansion and contraction of the introducer sheath, reducing the risk of vessel trauma and lowering insertion forces, while allowing for the passage of large profile devices without the need for additional steps or prolonged balloon inflation.
Implementation Method 1
an inner folded shape-memory layer having an inside passage; wherein the inner folded shape-memory layer has a first inside diameter in a folded condition and is expandable to a second inside diameter during passage of a device through the inside passage
Implementation Method 2
the elastomeric outer layer is constructed to compress the inner folded shape-memory layer which has been expanded to the second inside diameter by passage of the device so that the inner folded shape-memory layer is compressed to a folded state
Data Source
AI summary
An expandable introducer sheath for use in interventional procedures. The expandable introducer sheath can be inserted into a treatment vessel in a first unexpanded configuration. The expandable introducer sheath can expand in diameter during insertion of a device through its main lumen and can then re-collapse down to its unexpanded diameter. The device comprises an inner heat-set folded layer and an outer elastomeric layer. The outer elastomeric layer provides a barrier between the inner folded layer and a vessel wall during unfolding of the inner folded layer to minimize the risk of vessel trauma.