Surgical Navigation Localizer Motion Detection by Relative Tracker Comparison

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Solution Overview

Problem

Surgical navigation systems face issues with localizer movement that is undetectable, leading to inaccuracies in tracking and potential complications during surgeries.

Innovation Solution

A surgical navigation system that includes a first and second tracker, a localizer, and controllers to track and compare the relative motions of the trackers to detect movement of the localizer, using tracking and kinematic data, and apply filtering algorithms to enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the localizer moves during surgery, then the tracking data becomes inaccurate, but the system cannot detect this movement

Engineering Contradiction:
Improvetracking accuracyVSAvoidlocalizer stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors the relative motion patterns of multiple trackers and feeds this information back to detect localizer movement. By comparing expected tracker motion with actual observed motion, the system generates feedback signals that indicate when the localizer has moved, allowing for real-time correction or alerting.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary detection mechanism that does not directly track the localizer but instead tracks multiple objects relative to the localizer. By using these trackers as intermediaries, the system indirectly detects localizer movement through changes in the relative motion patterns of the tracked objects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple trackers are used to detect localizer movement, then detection accuracy improves, but system complexity increases

Engineering Contradiction:
Improvelocalizer movement detection accuracyVSAvoidnumber of trackers and processing requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the tracking task into multiple independent tracker units, each monitoring a specific region or object. By segmenting the detection function across multiple trackers, the system achieves better overall detection accuracy while maintaining modular simplicity in each individual tracker component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines the data from multiple trackers into a unified motion analysis framework. By merging the tracking information and analyzing collective motion patterns, the system achieves accurate localizer movement detection while sharing processing loads across multiple sensors, thereby managing complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If real-time comparison of tracker motions is performed, then localizer movement is detected promptly, but processing time and computational load increase

Engineering Contradiction:
Improvedetection response timeVSAvoidcomputational processing load
Core Design Contradiction:
SpeedVSUse of energy by stationary object

Solution Approach 1:

The system performs partial comparisons of tracker motions, focusing only on the essential motion parameters needed to detect localizer movement. By implementing just enough comparison logic to achieve reliable detection without exhaustive analysis of all motion dimensions, the system maintains fast response times while limiting computational overhead.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The motion comparison operates continuously at optimized intervals, maintaining constant monitoring capability without excessive processing. The system sustains useful detection action through streamlined continuous operation rather than intermittent intensive processing, balancing responsiveness with energy efficiency.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4670664A1Surgical navigation systems and methods for detecting localizer motion
Publication Date: 2025.12.31 MAKO SURGICAL CORP
  • EP4670664A1 patent drawingFigure 1
  • EP4670664A1 patent drawingFigure 2
  • EP4670664A1 patent drawingFigure 3

AI summary

Systems and methods for detecting localizer motion are provided. One such system is a surgical navigation system which includes a first tracker, a second tracker, a localizer, and one or more controllers. The localizer is configured to track the first tracker to generate first tracking data, and to track the second tracker to generate second tracking data. The one or more controllers are configured to receive the first tracking data and the second tracking data, calculate a relative motion of the first tracker based on the first tracking data, calculate a relative motion of the second tracker based on the second tracking data, compare the relative motions of the first and second trackers to one another, and detect a movement of the localizer based on the comparison.