Expandable Constraint Deflection Mechanism for Catheters

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Solution Overview

Problem

Current deflection catheter designs face challenges in achieving significant deflection of body lumens due to external constraints like connective tissue, requiring high pull forces that are difficult to achieve due to constrained pull wires, which limits mechanical advantage and increases force requirements.

Innovation Solution

A deflection mechanism with expandable constraints that allows the pull wire to move laterally away from the beam during deflection, providing greater mechanical advantage while limiting the maximum distance to maintain consistency with body lumen dimensions, combined with a catheter system that includes inflatable balloons to expand the lumen and facilitate deflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pull wire is constrained within the catheter shaft, then the device diameter is reduced for easier introduction, but the mechanical advantage is limited and high pull forces are required to deflect the body lumen

Engineering Contradiction:

Improveforce required to deflect body lumenVSAvoidconstraint mechanism structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The constraint member transitions from a constrained state during catheter insertion to an expanded state during deflection. The constraint member is configured to constrain the pull wire to movement within a first distance when compressed, and allow movement beyond this distance when expanded, enabling dynamic adaptation to different operational phases

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The constraint member is divided into multiple segments or sections that can move relative to each other. This segmentation allows the constraint member to expand and contract along its length, providing the necessary mechanical advantage during deflection while maintaining a compact profile during insertion

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the pull wire is allowed to move freely away from the beam, then greater mechanical advantage is achieved, but the maximum deflection distance cannot be controlled

Engineering Contradiction:

Improvemechanical advantageVSAvoiddeflection distance control

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The constraint member dynamically adjusts its constraint level based on the deflection phase. During initial deflection, it allows greater pull wire movement for mechanical advantage, then progressively constrains movement as the desired deflection distance is approached, achieving both mechanical advantage and precision control

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The constraint member provides inherent feedback through its mechanical structure. As the pull wire moves away from the beam, the constraint member responds by increasing its constraining force, automatically regulating the deflection distance without requiring external control mechanisms

Inventive Principle:

Principle #23Feedback

3Force

If high pull forces are applied to overcome external constraints like connective tissue, then significant deflection is achieved, but the force requirements become difficult to meet with conventional constrained pull wires

Engineering Contradiction:

Improvedeflection forceVSAvoidforce application feasibility

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The constraint member enables the pull wire to transition from a constrained configuration during insertion to an expanded configuration during force application. This dynamic expansion allows the pull wire to achieve greater lateral displacement, converting axial pull force into more effective lateral deflection force to overcome external constraints like connective tissue

Inventive Principle:

Principle #15Dynamics

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 the force required to deflect a body lumen, allows for easier introduction and positioning, and provides a safer and more effective method for clinical applications by minimizing tissue damage and maintaining the circular profile of the lumen.

Implementation Method 1

allows the pull wire to move laterally away from the beam during deflection, providing greater mechanical advantage

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

catheter system that includes inflatable balloons to expand the lumen

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS11744993B2System and method for deflection mechanism with expandable constraint

Publication Date: 2023.09.05 INNOVATIONS IN MEDICINE LLC

AI summary

A deflection system for deflecting a body lumen that includes a deflection mechanism, wherein the deflection mechanism includes: a beam having a proximal end and a distal end, wherein the beam includes a neutral position and a deflected position, a pull wire coupled to the distal end of the beam, wherein the beam is configured to be placed in the deflected position when a tension force is applied to the pull wire, and wherein at least a portion of the pull wire is configured to move to a displacement distance away from the beam when the tension force is applied to the pull wire, and one or more constraint members operatively coupled to the beam, wherein each one of the one or more constraint members is configured to limit the displacement distance of the pull wire from the beam when the tension force is applied to the pull wire.