Steerable Elongate Instrument with Shape Memory Alloy Stiffness Control

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Solution Overview

Problem

Minimally invasive surgical procedures are challenging due to the difficulty in using and controlling extension tools, limiting the number of surgeons skilled enough to perform complex procedures, which may lead to the preference for standard surgical methods despite their lesser benefits for patients.

Innovation Solution

Development of a steerable elongate instrument with adjustable shape and articulation control, featuring flexible and movable tubes that can be manipulated to conform to body pathways, using a combination of passive and active control mechanisms to facilitate precise navigation and control within the body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If extension tools are used for minimally invasive surgical procedures, then physical trauma to the patient is minimized, but the difficulty of manipulating and controlling the tools increases

Engineering Contradiction:

Improvephysical trauma to patientVSAvoiddifficulty of manipulating extension tools

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The instrument incorporates a shape memory alloy wire that can dynamically change the stiffness of the elongate body from flexible to rigid states. This allows the instrument to be flexible during insertion to minimize trauma, then become rigid when positioned to enable precise control and manipulation for the surgical procedure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the physical parameter of stiffness by utilizing the phase transition properties of shape memory alloy. By applying thermal or mechanical activation, the alloy transitions between austenite (rigid) and martensite (flexible) phases, thereby adjusting the instrument's stiffness to match different operational requirements - flexible for navigation, rigid for manipulation

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If standard surgical procedures are used instead of minimally invasive procedures, then ease of manipulation is improved, but physical trauma to the patient increases

Engineering Contradiction:

Improveease of manipulationVSAvoidphysical trauma to patient

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The dynamic stiffness adjustment capability allows the instrument to provide easy manipulation when needed (rigid state) while still enabling minimally invasive access (flexible state during insertion), thus combining the benefits of both standard and minimally invasive approaches

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

By changing the stiffness parameter in-situ after insertion, the instrument achieves precise controllability similar to standard surgical tools without requiring large incisions, thereby maintaining minimal patient trauma while improving ease of manipulation

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If flexible elongate instruments are used to navigate body pathways, then adaptability to body pathways is improved, but control precision deteriorates

Engineering Contradiction:

Improveadaptability to body pathwaysVSAvoidcontrol precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The instrument dynamically adjusts its mechanical properties from flexible to rigid based on operational phase - flexible during navigation to adapt to body pathways, then rigid when positioned to ensure precise control and stable manipulation during the surgical procedure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The phase transition of the shape memory alloy enables parameter change in stiffness, allowing the instrument to be compliant and adaptable during insertion and navigation, then transition to a rigid state with high structural integrity for precise positioning and controlled surgical operations

Inventive Principle:

Principle #35Parameter changes

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 instrument allows for easier manipulation and control, enabling more surgeons to perform complex minimally invasive procedures with precision, reducing physical trauma to patients and recovery time.

Implementation Method 1

a shape memory alloy wire configured to change the stiffness of the elongate body from flexible to rigid

Methodology Applied

Scientific EffectShape memory alloy: Shape Memory Alloy

Data Source

PatentEP3090776B1Flexible and steerable elongate instruments with shape control and support elements

Publication Date: 2020.08.12 AURIS HEALTH INC

Figure 1
Figure 2A~2B
Figure 2C

AI summary

An instrument having a flexible and elongated body includes at least a lumen and a flex member disposed within the lumen. The flex member may be capable of providing steering control to a first portion of the elongate body while providing load bearing support to a second portion of the elongate body. A pull wire may be disposed within the flex member, and at least a distal portion of the pull wire may be coupled to the elongate body and a proximal portion of the pull wire may be operatively coupled to a control unit. The control unit may be coupled to a proximal portion of the elongate body.