Surgical Navigation With Tool Profile Calibration for Asymmetrical Tools

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Solution Overview

Problem

Existing surgical navigation systems are not operational for asymmetrical tools and have limited accuracy in determining the pose of surgical tools due to neglecting the general shape or profile of the tool.

Innovation Solution

A surgical navigation system that includes a calibrating device with a reflector and holder to capture the profile of the surgical tool using infrared radiation, allowing the data processor to compute the pose accurately by considering the tool's actual shape, even for asymmetrical tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If only the rotating axis and tip are taken into account for pose computation, then the system is simple to operate, but the measurement precision of the surgical tool pose is limited

Engineering Contradiction:
Improvepose computation accuracyVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from tracking only 1D/2D points (tip and rotating axis) to capturing the full 3D profile of the surgical tool. The profile capture device records the complete cross-sectional shape of the tool, adding dimensional information that enables more accurate pose computation through profile matching algorithms, thereby resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent creates a digital copy of the surgical tool's profile by capturing its geometric shape with the profile capture device. This digital profile model is then used for comparison and matching during pose computation, allowing the system to achieve high measurement precision by referencing the known profile shape without requiring complex physical calibration artifacts.

Inventive Principle:
Principle #26Copying

2Adaptability or versatility

If the general shape (profile) of the surgical tool is not considered, then the calibration device is simpler, but the system cannot accurately calibrate asymmetrical surgical tools

Engineering Contradiction:
Improvecompatibility with asymmetrical toolsVSAvoidcalibration device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal calibration system that can handle both symmetrical and asymmetrical surgical tools through the profile capture device. By capturing and storing the specific profile of each tool, the system becomes adaptable to different tool geometries without requiring tool-specific calibration mechanisms, thus achieving versatility while maintaining relatively simple device architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the calibration approach from relying on fixed geometric assumptions (suitable only for symmetrical tools) to using captured profile parameters that can represent any tool shape. The profile capture device records specific geometric parameters of each tool's cross-section, allowing the calibration algorithm to adapt to asymmetrical geometries by using these measured parameters rather than assuming symmetry.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If manual radius input is required for error correction, then the automation level is reduced, but the calibration accuracy can be improved

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration process automation
Core Design Contradiction:
Measurement precisionVSExtent of automation

Solution Approach 1:

The patent implements a self-calibrating system where the profile capture device automatically records the tool's profile and the processing unit automatically performs the matching and error correction calculations. The system serves itself by using the captured profile data to automatically adjust and improve calibration accuracy without requiring manual radius input or operator intervention, thus maintaining high automation while achieving improved precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates a feedback mechanism where the captured profile is compared against the stored reference profile, and the difference is used to automatically correct pose computation errors. The processing unit continuously refines the calibration by using the profile matching feedback, eliminating the need for manual error correction while maintaining high calibration accuracy through automated iterative improvement.

Inventive Principle:
Principle #23Feedback

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

Improves the accuracy of surgical tool pose computation by capturing and processing the tool's profile, enabling precise navigation of asymmetrical tools.

Implementation Method 1

a light source, configured to emit infrared radiations

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

the camera is arranged to detect the infrared radiations which are reflected by the surgical tool and by the reflector

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4302718B1Surgical navigation system
Publication Date: 2025.08.27 ECENTIAL ROBOTICS
  • EP4302718B1 patent drawingFigure 1~2
  • EP4302718B1 patent drawingFigure 3~4
  • EP4302718B1 patent drawingFigure 5~6

AI summary

A surgical navigation system, comprising: - a surgical tool (1), having a profile (10); - an optical tracking system, comprising: a light source (S), configured to emit infrared radiations; an optical tracker (2); a camera (3); a data processor; - a calibrating device, configured to calibrate the surgical tool (1) tracked by the optical tracking system; and comprising: a reflector (5); a holder (6); wherein the light source (S) is arranged to irradiate the profile of the surgical tool (1) held by the holder (6), the camera (3) is arranged to detect the infrared radiations which are reflected by the surgical tool (1) and by the reflector (5) so as to capture images of the profile (10) of the surgical tool (1), and the data processor is configured to compute the pose of the surgical tool (1) from the captured images of both the optical tracker (2) and the profile (10) of the surgical tool (1).