Introducer Sheath Helical Strand Segmentation

Solution Overview

Problem

Conventional introducer sheaths with coil or braid reinforcements tend to stretch and elongate during deployment of longer or coated medical devices, leading to inefficiencies in stent deployment due to increased radial forces and reduced sheath diameter, which can hinder full deployment and require higher push forces.

Innovation Solution

A sheath design comprising a tubular proximal segment with a helical strand profile and a distal segment with a reinforcing coil, where the proximal segment has a greater length and smaller diameter than the distal segment, and a tapered transition between them, minimizing elongation and maintaining radial integrity during stent deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a coil reinforcement is used in the sheath to minimize kinking and ovalization, then the sheath maintains flexibility and kink resistance, but the sheath tends to stretch longitudinally during withdrawal from longer or coated devices, causing elongation and reducing deployment effectiveness

Engineering Contradiction:

Improvekink resistanceVSAvoidsheath elongation

Core Design Contradiction:

Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The sheath is divided into multiple segments with different reinforcement structures: a proximal segment with coil reinforcement for kink resistance and a distal segment with braid reinforcement for minimal elongation. This segmentation allows each part to perform its specialized function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the sheath are given different local properties: the proximal segment has coil reinforcement optimized for flexibility and kink resistance where the sheath is manipulated, while the distal segment has braid reinforcement optimized for minimal elongation where it contacts the deployed device.

Inventive Principle:

Principle #3Local quality

2Strength

If a braid reinforcement is used in the sheath to impart stiffness and pushability, then the sheath gains structural support, but the sheath is prone to longitudinal stretching upon withdrawal due to increased deployment forces

Engineering Contradiction:

ImprovepushabilityVSAvoidsheath elongation

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The sheath is divided into multiple segments with different reinforcement structures: a proximal segment with coil reinforcement for kink resistance and a distal segment with braid reinforcement for minimal elongation. This segmentation allows each part to perform its specialized function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the sheath are given different local properties: the proximal segment has coil reinforcement optimized for flexibility and kink resistance where the sheath is manipulated, while the distal segment has braid reinforcement optimized for minimal elongation where it contacts the deployed device.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the sheath is designed with uniform diameter throughout, then the structure is simple to manufacture, but the sheath cannot efficiently handle longer or coated devices that require varying flexibility and structural support along its length

Engineering Contradiction:

Improvestructural simplicityVSAvoiddevice compatibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The sheath is divided into multiple segments with different reinforcement structures: a proximal segment with coil reinforcement for kink resistance and a distal segment with braid reinforcement for minimal elongation. This segmentation allows each part to perform its specialized function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the sheath are given different local properties: the proximal segment has coil reinforcement optimized for flexibility and kink resistance where the sheath is manipulated, while the distal segment has braid reinforcement optimized for minimal elongation where it contacts the deployed device.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9119740B2Introducer sheath

Publication Date: 2015.09.01 COOK MEDICAL TECHNOLOGIES LLC

AI summary

An introducer sheath has a proximal segment and distal segment. The proximal segment includes an inner portion, and a polymeric outer covering portion. The inner portion is formed from a plurality of elongated strands circularly positioned around a longitudinal axis. Each strand includes axial twist portions arranged to define a generally helical strand profile, wherein the twist portions are complementary with twist portions of adjacent strands to define the tubular segment. A tubular distal segment is dimensioned to receive an elongated stent for deployment. The length of the proximal segment is greater than the length of the distal segment, and the outer diameter of the distal segment may exceed that of the proximal segment. A stability sheath may be received over the proximal segment to enhance the stability of the sheath.