Augmented Reality Surgical Tool Alignment with Real-Time EM Tracking

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Solution Overview

Problem

Existing computer-assisted surgical systems provide limited real-time assistance during surgeries, primarily focusing on pre-registered 3D imagery and are not effectively enhancing surgical workflows.

Innovation Solution

A computer-assisted surgical system (CASS) utilizing augmented reality (AR) and electromagnetic (EM) tracking systems with multiple sensors, including small diameter EM sensors inserted via pins, to provide real-time guidance and enhance surgical precision and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pre-registered 3D imageries are used for surgical assistance, then surgical preparation and planning are improved, but real-time surgical guidance and information provision are limited

Engineering Contradiction:
Improvesurgical precisionVSAvoidreal-time assistance
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system transitions from static pre-registered 3D imageries to dynamic real-time AR overlays that update continuously during surgery. The AR display dynamically superimposes anatomical structures, surgical tools, and guidance information onto the live surgical field view, enabling both precise preoperative planning and real-time adaptive guidance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an AR display system as an intermediary between the surgeon and the surgical field. This intermediary layer overlays virtual information (anatomical structures, tool positions, guidance cues) onto the physical surgical environment, allowing the surgeon to access multiple data sources simultaneously without diverting attention from the actual procedure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If traditional surgical displays are used, then surgical workflow is maintained, but additional real-time information and guidance are insufficient

Engineering Contradiction:
Improvesurgical efficiencyVSAvoidadditional information
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The system merges multiple information streams (preoperative imaging, intraoperative sensor data, tool positioning, anatomical overlays) into a single integrated AR display. This consolidation provides comprehensive real-time information without requiring the surgeon to switch between multiple screens or references, thereby improving efficiency and reducing cognitive load.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent adds a dimensional layer of virtual information overlay onto the physical surgical field. By projecting 3D anatomical models, tool trajectories, and measurement data directly onto the surgical site through AR, the system creates an enhanced perceptual dimension that combines physical and digital information spaces.

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

3Measurement precision

If electromagnetic sensors with small diameter are inserted via pins, then tracking precision is improved, but device complexity and insertion procedures increase

Engineering Contradiction:
Improvetracking precisionVSAvoidsensor insertion system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system employs disposable pin trackers with integrated electromagnetic sensors that are inserted during surgery and removed afterward. These single-use trackers eliminate the need for complex reusable sensor arrays and simplify the tracking infrastructure, reducing overall system complexity while maintaining high precision through the small-diameter pin insertion method.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

Enables real-time, precise surgical procedures by providing additional information and guiding surgeons through AR displays, improving surgical accuracy and efficiency.

Implementation Method 1

electromagnetic (EM) tracking systems with multiple sensors, including small diameter EM sensors inserted via pins

Methodology Applied
Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Data Source

PatentEP3937825B1Augmented reality assisted surgical tool alignment
Publication Date: 2025.08.06 SMITH & NEPHEW INC
  • EP3937825B1 patent drawingFigure 1
  • EP3937825B1 patent drawingFigure 2
  • EP3937825B1 patent drawingFigure 3A~3C

AI summary

Computer-assisted surgical systems and methods for assisting with tool alignment using one or more mixed reality displays are disclosed. The system may provide for obtaining an existing surgical plan that may include specific patient information and data about the surgical procedure. The system may receive from a tracking system, locational information of a patient bone and determine, based on the surgical plan and the locational information, a preferred location and angle for use of a surgical device. Once determined, the system may display on a mixed reality display one or more visual indicators associated with the preferred location and the preferred angle.