Expandable Introducer Sheath With Embedded Coil

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Solution Overview

Problem

Existing introducer devices often require large sheaths to accommodate large delivery devices, leading to larger incisions and increased trauma and complications during minimally invasive procedures.

Innovation Solution

An expandable introducer device with a sheath that radially expands from a folded state to an unfolded state, featuring a thick wall region with a coil embedded in the sheath wall, allowing for increased diameter accommodation while maintaining a compact folded state, and utilizing shape memory materials for expansion and contraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a large sheath is used to accommodate large delivery devices, then the delivery device can be delivered to the desired site, but the incision size increases and causes more trauma and complications

Engineering Contradiction:

Improvedelivery device accommodation capabilityVSAvoidincision trauma and complications

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sheath is designed with dynamic expandability, transitioning from a compressed low-profile state during insertion to an expanded high-capacity state at the delivery site. The sheath wall includes embedded coils that enable radial expansion, allowing the same sheath to accommodate both small delivery devices during insertion and large delivery devices at the destination, thereby resolving the contradiction between delivery device accommodation capability and incision trauma.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If the sheath is made expandable with embedded coils, then smaller incisions are possible, but the device complexity increases

Engineering Contradiction:

Improveincision traumaVSAvoidsheath structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The sheath utilizes a flexible wall structure with embedded coils that can radially expand and contract. This flexible shell design allows the sheath to transition between compressed and expanded states, reducing incision trauma while maintaining structural integrity. The coil embedding provides the necessary mechanical complexity only where needed for expansion, rather than throughout the entire device.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The sheath design incorporates nested functionality where the embedded coils are integrated within the sheath wall layers. The thick wall region contains the coil structure, which is nested within the sheath material, creating a compact yet functional design that reduces overall device complexity compared to having separate expansion mechanisms.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Volume of moving object

If the sheath wall is made thin to reduce profile, then the folded state is more compact, but the structural strength decreases

Engineering Contradiction:

Improvefolded state compactnessVSAvoidsheath wall strength

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The sheath wall is designed with non-uniform thickness, featuring a thick wall region that contains the embedded coil and a thinner wall region for reduced profile. This local quality variation allows the sheath to maintain structural strength where needed (in the thick wall region with coil) while achieving compactness in other areas (thinner wall region), resolving the contradiction between folded state compactness and structural strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The sheath wall functions as a composite structure combining different material properties - the thick wall region with embedded coil provides structural reinforcement and expandability, while the thinner wall region provides flexibility and compactness. This composite approach allows the sheath to achieve both compact folded state and adequate structural strength.

Inventive Principle:

Principle #40Composite materials

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

Enables minimally invasive procedures with smaller incisions by accommodating larger devices within a smaller profile, reducing trauma and complications through controlled radial expansion and contraction.

Implementation Method 1

the coil is a shape memory material and is shape set to the radially unexpanded, folded state

Methodology Applied

Scientific EffectShape memory material: Shape Memory Alloy

Data Source

PatentUS20250001139A1Expandable introducer

Publication Date: 2025.01.02 MEDTRONIC INC

AI summary

An expandable introducer includes a hub having a distal end and a proximal end, and a sheath coupled to the hub and extending distally therefrom, the sheath defining a central lumen. The sheath is configured to radially expand from a radially unexpanded, folded state having a first diameter and to a radially expanded, unfolded state having a second diameter larger than the first diameter in response to a device passing through the central lumen. A wall of the sheath includes a thick wall region having a first wall thickness and a thin wall region having a second wall thickness smaller than the first wall thickness, wherein the thick wall region includes a coil embedded within the wall of the sheath.