Stent Deployment via Cannula Coiled Member Rotation

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Solution Overview

Problem

Conventional stent deployment systems using trigger wires can cause damage to stents, especially nickel-titanium ones, due to crimping and entanglement issues, and require high deployment forces, which complicates the delivery and positioning of stents in vascular procedures.

Innovation Solution

A system employing a cannula with a coiled member where a portion of the stent is looped around the unsecured end of the coiled member, allowing rotation to disengage the stent from the coiled member for deployment, reducing the need for trigger wires and minimizing stent damage, while enabling more precise and controlled deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If trigger wires are used to deploy the stent, then the stent can be deployed, but the trigger wires may become crimped at the vertices during compression, causing damage to the stent and trigger wires

Engineering Contradiction:

Improvestent deployment reliabilityVSAvoidcrimping damage to stent and trigger wires

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the trigger wire component entirely from the stent deployment system. Instead of using trigger wires that loop through vertices and cause crimping, the invention uses a delivery catheter with a expandable balloon that inflates to deploy the stent, eliminating the harmful crimping effect while maintaining deployment functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an expandable balloon as an intermediary mechanism between the delivery catheter and the stent. The balloon serves as a mediator that applies uniform radial force to expand the stent without direct mechanical contact and crimping, replacing the direct trigger wire-stent interaction that causes damage

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If multiple trigger wires are used to control stent deployment, then deployment control is improved, but the profile of the delivery system increases

Engineering Contradiction:

Improvestent deployment controlVSAvoiddelivery system profile

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The patent combines multiple deployment control functions into a single balloon mechanism. Instead of using multiple separate trigger wires that would increase the delivery profile, the single balloon performs both the deployment and control functions, reducing the overall volume and profile of the delivery system while maintaining operational control

Inventive Principle:

Principle #5Merging (Combining)

3Volume of moving object

If trigger wires are used with acute bend stents, then the stent can be compressed to reduced diameter, but barbs near the apices may become entangled with stent struts and trigger wires

Engineering Contradiction:

Improvestent delivery profileVSAvoidbarb entanglement

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent removes the trigger wire component that causes barb entanglement. By using balloon expansion instead of trigger wires, the system eliminates the mechanical interaction between trigger wires and barbs that causes entanglement, while still achieving compressed delivery and controlled deployment

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical trigger wire system with a pneumatic/hydrodynamic balloon expansion system. This substitution eliminates the direct mechanical contact and friction between trigger wires and barbs, preventing entanglement while maintaining the ability to compress and deploy the stent

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach reduces stent damage, simplifies deployment, and allows for more precise positioning of the stent, minimizing the radial profile of the delivery system and reducing deployment forces, thereby enhancing the efficiency and accuracy of stent placement in vascular procedures.

Implementation Method 1

at least one coiled member having proximal and distal ends and a plurality of turns disposed therebetween

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2674135B1Systems and methods for deploying a portion of a stent using at least one coiled member

Publication Date: 2017.10.18 COOK MEDICAL TECHNOLOGIES LLC

AI summary

The present embodiments provide systems and methods for deploying at least a portion of a stent. In one embodiment, the system comprises a cannula (30) having an outer surface, and at least one coiled member (40) having proximal and distal ends and a plurality of turns disposed therebetween. One of the proximal and distal ends of the coiled member (40) is secured to the outer surface of the cannula (30), and the other of the proximal and distal ends of the coiled member (40) is unsecured relative to the outer surface of the cannula (30). A portion of a stent (60) is looped around the unsecured end of the coiled member (40) and disposed within spacing between adjacent turns of the coiled member (40). Rotation of the cannula (30) subsequently causes the portion of the stent (60) to disengage from the coiled member (40). A protective cage may encircle the coiled member (30).