Fiber Optic Shape Sensing for Steerable Medical Instruments

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Solution Overview

Problem

Conventional medical instruments for minimally invasive procedures lack accurate shape measurement capabilities, leading to errors in control and navigation due to unmodeled anatomical constraints and environmental interactions, which affect the actual position and shape of shapeable instruments during procedures.

Innovation Solution

A robotic medical system that incorporates a localization system to measure the shape of shapeable instruments using fiber optic sensors and other localization technologies, providing real-time shape data for feedback to improve control and navigation by comparing actual shapes with desired configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional control systems are used without shape measurement, then the device complexity is lower, but the control precision and navigation accuracy deteriorate due to unmodeled anatomical constraints

Engineering Contradiction:
Improveshape measurement precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical shape sensing methods with optical fiber-based sensing. Optical fibers are embedded within the shapeable instrument to directly measure shape, eliminating the need for complex mechanical models and inference algorithms. This substitution provides direct shape measurements with high precision while keeping the overall system relatively simple.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from indirect mechanical inference to direct optical measurement. By using optical fibers that detect shape through light propagation characteristics, the system achieves precise shape measurement without requiring complex mechanical models or multiple sensors, thus improving measurement precision without proportionally increasing system complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If shape measurement is not incorporated, then the device complexity is lower, but the control reliability deteriorates due to errors from unmodeled constraints

Engineering Contradiction:
Improvecontrol reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by continuously measuring the actual shape of the shapeable instrument using embedded optical fibers and comparing it with the desired configuration. The control system generates correction signals based on the shape differential, creating a closed-loop control mechanism that improves reliability by compensating for unmodeled anatomical constraints and environmental interactions.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If fiber optic sensors are embedded in the instrument, then the shape measurement precision improves, but the device complexity increases

Engineering Contradiction:
Improveshape measurement precisionVSAvoidinstrument complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies nesting by embedding optical fibers within the existing structure of the shapeable instrument. The optical fibers are integrated into the instrument body, utilizing the existing lumens and structural spaces. This nesting approach allows shape measurement functionality to be added without significantly increasing the external dimensions or overall complexity of the instrument.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Measurement precision

If real-time shape feedback is provided, then the navigation accuracy improves, but the use of energy increases due to continuous measurement and processing

Engineering Contradiction:
Improvenavigation accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by updating shape measurements and control signals at discrete time intervals rather than continuously. The system captures shape data at regular intervals, processes the information, and updates control commands periodically. This approach maintains navigation accuracy by providing timely feedback while reducing energy consumption by avoiding constant measurement and processing operations.

Inventive Principle:
Principle #19Periodic action

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

Enhances the precision and accuracy of medical instrument control by providing real-time shape feedback, reducing errors and improving navigation within anatomical regions, thereby improving procedure outcomes.

Implementation Method 1

at least one optical fiber in communication with one or more optical gratings and having a distal end configured to measure a shape of at least a portion of the elongate member

Methodology Applied
Scientific EffectBragg diffraction: Bragg Diffraction

Implementation Method 2

obtaining a plurality of data of Rayleigh scatter of the optic fiber

Methodology Applied
Scientific EffectRayleigh scattering: Rayleigh Scattering

Data Source

PatentEP2584991B1Fiber optic instrument sensing system
Publication Date: 2020.11.25 AURIS HEALTH INC
  • EP2584991B1 patent drawingFigure 1A~1B
  • EP2584991B1 patent drawingFigure 1C~1D(c)
  • EP2584991B1 patent drawingFigure 2A~2B

AI summary

Systems are described herein that improve control of a shapeable or steerable instrument using shape data. Additional systems use such shape data for improved mapping or adjusting models of the instrument. Such systems include robotic medical systems for controlling a shapeable instrument within an anatomical region having a controller, one or more actuators, and a localization system for guiding one or more shapeable instruments.