Optical Tracking Force Measurement for Flexible Surgical Tools

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Solution Overview

Problem

Existing orthopedic implant procedures face challenges in accurately determining the force applied to a joint, leading to inconsistent surgical outcomes due to subjective force application and the lack of objective force measurement tools, which are often costly and require additional components.

Innovation Solution

A surgical system utilizing an optical tracking system to measure force applied to a device, providing real-time data on force magnitude and direction, integrated with a computer-assisted surgical system to enhance surgical workflows and reduce the need for additional force measurement tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional force measurement tools are used, then force measurement capability is provided, but device complexity and cost increase due to additional components

Engineering Contradiction:
Improveforce measurementVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical tracking system is designed to serve multiple functions: it tracks the position and orientation of surgical instruments while also measuring forces applied to the joint. By integrating force measurement capabilities into the existing tracking system rather than adding separate measurement devices, the system achieves multi-functionality that reduces overall complexity and cost.

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

Solution Approach 2:

The patent combines force measurement functionality with the optical tracking system by integrating force sensors into the instrument or using the tracking system to monitor displacement and calculate forces. This merging of functions eliminates the need for independent force measurement devices, thereby reducing device complexity while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If conventional force measurement tools are used, then force measurement capability is provided, but cost increases due to additional components

Engineering Contradiction:
Improveforce measurementVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The optical tracking system is designed to serve multiple functions: it tracks the position and orientation of surgical instruments while also measuring forces applied to the joint. By integrating force measurement capabilities into the existing tracking system rather than adding separate measurement devices, the system achieves multi-functionality that reduces overall complexity and cost.

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

Solution Approach 2:

The system uses its own optical tracking infrastructure to derive force measurement data through displacement tracking and calculation, rather than requiring external dedicated force measurement equipment. This self-service approach leverages existing system resources to provide additional measurement capabilities without increasing manufacturing costs.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If subjective force application is used in implant procedures, then surgical flexibility is maintained, but measurement precision and consistency deteriorate

Engineering Contradiction:
Improvesurgical flexibilityVSAvoidforce application consistency
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system provides real-time feedback to the surgeon about the forces being applied to the joint during the procedure. By continuously monitoring displacement through optical tracking and calculating corresponding forces, the system gives objective numerical feedback that helps the surgeon maintain consistent and appropriate force levels, improving measurement precision while preserving surgical flexibility.

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

The system enables standardized, objective force measurement during surgical procedures, improving surgical accuracy and reducing costs by leveraging existing tracking systems, thereby enhancing surgical outcomes.

Implementation Method 1

A surgical system utilizing an optical tracking system to measure force applied to a device

Methodology Applied
Scientific EffectOptical tracking: Light

Data Source

PatentEP3930584B1Measuring force using a tracking system
Publication Date: 2025.10.15 SMITH & NEPHEW INC
  • EP3930584B1 patent drawingFigure 1
  • EP3930584B1 patent drawingFigure 2A
  • EP3930584B1 patent drawingFigure 2B

AI summary

Methods of measuring a force using a tracking system are disclosed. A first vector is determined between a first tracking array and a second tracking array on a tool. The tool has a flexible portion that has a known modulus of elasticity and moment of inertia. A force is applied to the tool, and a second vector is determined between the first tracking array and the second tracking array. An amount of deflection is determined for the tool, and the magnitude and direction of the applied force are determined based on at least the amount of deflection, the modulus of elasticity and the moment of inertia. Information pertaining to the magnitude and direction of the applied force is provided to a user.