Inertial Sensor Positioning Block for Bone Alteration

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Solution Overview

Problem

Current computer-assisted surgery systems face challenges with the size and visibility requirements of tracking systems, particularly in orthopedic surgeries, where miniaturized technologies providing fewer than 6 degrees of freedom are lacking, leading to inaccuracies and difficulties in integrating tracking devices with disposable instruments.

Innovation Solution

A computer-assisted surgery system utilizing a positioning block with an inertial sensor unit providing orientation-based data for at least two degrees of freedom, allowing adjustable orientation and integration with a processing system for calculating bone alteration parameters, which includes a caliper for dimension measurement using MEMS sensors and a polyaxial mounting screw for secure bone attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional optical tracking systems with multiple light sources are used, then six degrees of freedom tracking precision is achieved, but the device size becomes large and obstructive

Engineering Contradiction:

Improvetracking precisionVSAvoidtrackable reference size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces traditional optical tracking systems with electromagnetic tracking technology. The electromagnetic field-based tracking eliminates the need for large optical elements and light sources, achieving six degrees of freedom tracking with a compact form factor that can be integrated into disposable surgical instruments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the tracking methodology from optical to electromagnetic parameters. By using electromagnetic fields instead of light, the system achieves the same tracking precision with significantly reduced physical dimensions of the trackable references.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If active tracking systems with transmitters are used, then position and orientation data are obtained, but wires are required in sterile zones

Engineering Contradiction:

Improveposition and orientation dataVSAvoidwire presence in sterile zone

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces wired active tracking systems with wireless electromagnetic tracking. The electromagnetic transmitters communicate position and orientation data wirelessly through the electromagnetic field, eliminating the need for physical wires in sterile surgical zones while maintaining tracking precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If passive optical tracking elements are used, then no power source is needed, but line of sight visibility is required between sensor and elements

Engineering Contradiction:

Improvepower source requirementVSAvoidline of sight visibility requirement

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent replaces line-of-sight optical tracking with electromagnetic tracking. Electromagnetic waves can penetrate through tissue and obstacles, eliminating the line of sight requirement while maintaining the advantage of no power source needed for the trackable reference elements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Volume of moving object

If miniaturized tracking technologies are used, then device size is reduced, but fewer than 6 degrees of freedom are provided

Engineering Contradiction:

Improvetracking device sizeVSAvoiddegrees of freedom

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent uses electromagnetic field interactions to achieve six degrees of freedom tracking with miniaturized components. The electromagnetic tracking system can determine three positional coordinates and three orientational angles using compact transmitters and receivers, unlike mechanical or optical systems that require larger physical structures.

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 solution enhances precision and ease of use in orthopedic surgeries by providing accurate orientation data for bone alterations and implant placement without the need for external tracking systems, reducing the invasiveness and complexity of surgical procedures.

Implementation Method 1

an inertial sensor unit producing orientation-based data for at least two degrees of freedom in orientation of the positioning block

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS10251653B2Method and system for planning/guiding alterations to a bone

Publication Date: 2019.04.09 ORTHOSOFT ULC

AI summary

A computer-assisted surgery system for guiding alterations to a bone, comprises a trackable member secured to the bone. The trackable member has a first inertial sensor unit producing orientation-based data. A positioning block is secured to the bone, and is adjustable once the positioning block is secured to the bone to be used to guide tools in altering the bone. The positioning block has a second inertial sensor unit producing orientation-based data. A processing system providing an orientation reference associating the bone to the trackable member comprises a signal interpreter for determining an orientation of the trackable member and of the positioning block. A parameter calculator calculates alteration parameters related to an actual orientation of the positioning block with respect to the bone.