Medical Navigation Instrument Identification via Dynamic Marker Distance Measurement

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Solution Overview

Problem

Medical navigation systems face challenges in accurately identifying instruments with marker elements, particularly those that are inaccurately produced or have undergone deformation, due to stringent production accuracy requirements and stored geometries that do not match altered instrument geometries.

Innovation Solution

A method using a medical optical tracking system to measure the relative distances of marker elements on a reference array, allowing for identification of the instrument without pre-stored marker geometries, by recognizing the rigid body geometry and assigning it to the instrument, enabling the use of cost-effective and deformed instruments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pre-stored marker geometries are used for instrument identification, then identification accuracy is improved, but manufacturing precision requirements increase and deformed instruments cannot be identified

Engineering Contradiction:

Improveinstrument identification accuracyVSAvoidproduction accuracy requirement

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The system transitions from static pre-stored geometries to dynamic real-time measurement of marker element positions and distances. The navigation system actively measures current spatial arrangements during surgery, allowing identification of instruments regardless of manufacturing variations or deformation, thus resolving the contradiction between identification accuracy and manufacturing precision requirements

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the identification parameter from fixed geometric templates to measured spatial distances between marker elements. By using actual measured distances rather than comparing against stored ideal geometries, the system can accommodate variations in manufacturing precision while maintaining reliable instrument identification

Inventive Principle:

Principle #35Parameter changes

2Reliability

If pre-stored marker geometries are used, then identification reliability is improved, but adaptability to deformed or reused instruments deteriorates

Engineering Contradiction:

Improveidentification reliabilityVSAvoidadaptability to deformed instruments

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system implements feedback by continuously measuring the actual spatial arrangement of marker elements during surgery and using this real-time information for instrument identification. This feedback mechanism allows the system to adapt to any instrument configuration, including deformed or reused instruments, while maintaining reliable identification through active measurement rather than relying on pre-stored ideal geometries

Inventive Principle:

Principle #23Feedback

3Measurement precision

If high production accuracy is required for marker geometries, then identification accuracy is improved, but instrument cost increases

Engineering Contradiction:

Improvespatial arrangement identification accuracyVSAvoidinstrument manufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The system replaces the mechanical requirement for high-precision manufacturing with an optical/measurement-based solution. Instead of relying on mechanically precise instrument fabrication, the system uses optical tracking to measure marker element positions and calculate spatial distances, substituting manufacturing precision requirements with measurement capability, thereby reducing instrument costs while maintaining identification accuracy

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 method enhances the reliability and applicability of surgical navigation systems by reducing production accuracy demands, allowing the use of inexpensive, disposable instruments and instruments that have changed geometry due to use, while avoiding errors by dynamically identifying the instrument's spatial arrangement.

Implementation Method 1

using a medical optical tracking system that is assigned to the navigation system

Methodology Applied

Scientific EffectOptical tracking:

Implementation Method 2

a distance of the marker elements (A, B, C) from each other is measured

Methodology Applied

Scientific EffectDistance calculation:

Data Source

PatentUS9622824B2Method for automatically identifying instruments during medical navigation

Publication Date: 2017.04.18 BRAINLAB AG

AI summary

A method for using a medical navigation system to identify an instrument to be navigated is provided, wherein the instrument includes a reference array having a plurality of markers that form a rigid body, and a location of the markers with respect to each other is not previously known in the navigation system as a characteristic arrangement for a particular instrument. The method includes measuring a distance of each marker relative to the other markers; identifying a spatial arrangement of the markers having the measured distance as an assignable marker array; assigning the assignable marker array to the instrument; and identifying the instrument based on the assigned marker array.