Surgical Tracker IR-LED Layout With Low-Current Button Cell Power

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Solution Overview

Problem

Existing surgical trackers for navigation systems face issues such as contamination susceptibility, weight imbalance causing surgeon fatigue, and structural deformation or damage due to battery packs or power cords, with pulsed operation requiring complex synchronization.

Innovation Solution

A tracker with an arrangement of infrared light emitting diodes (IR-LEDs) on a lightweight polymer carrier, powered by a single button cell battery, limiting current to 15mA per LED, allowing continuous or quasi-continuous operation without synchronization, and featuring a lightweight design and wireless power reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a battery pack or power cord is used to power the active tracker, then the tracker can generate light continuously, but the weight of the battery pack or power cord affects the centre of gravity and makes holding the instrument tiresome

Engineering Contradiction:
Improvepower supply capabilityVSAvoidtracker weight
Core Design Contradiction:
Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The patent employs disposable button cell batteries (e.g., CR2032, CR2025, CR2016, or CR2020) instead of rechargeable battery packs or power cords. These small, inexpensive batteries provide sufficient power for the duration of a surgical procedure, eliminating the need for heavy rechargeable systems while maintaining continuous light generation capability.

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

Solution Approach 2:

The patent reduces the current consumption of each IR-LED to not more than 15mA through circuit design optimizations. This parameter change allows the use of smaller, lighter button cell batteries that can sustain continuous operation throughout a surgical procedure without requiring heavy power sources.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the tracker uses a battery pack or power cord, then the tracker can operate continuously, but structurally weak instruments like biopsy needles may deform or be damaged by the weight of the tracker

Engineering Contradiction:
Improvepower supply capabilityVSAvoidinstrument structural integrity
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The use of disposable button cell batteries eliminates the need for heavy rechargeable battery packs and power cords that could deform or damage structurally weak instruments like biopsy needles. The minimal weight of the button cell battery and lightweight tracker housing preserves instrument integrity.

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

Solution Approach 2:

By reducing IR-LED current consumption to ≤15mA, the patent enables continuous operation with minimal power requirements, allowing the use of extremely lightweight components that do not compromise the structural strength of delicate surgical instruments.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the tracker operates in a pulsed manner to reduce power consumption, then the battery life is extended, but synchronization with the navigation camera is required which increases the complexity of the tracker

Engineering Contradiction:
Improvepower consumptionVSAvoidtracker complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent employs continuous operation of the IR-LEDs powered by small button cell batteries, eliminating the need for pulsed operation and camera synchronization. The low current consumption (≤15mA per LED) ensures sufficient battery life for continuous illumination throughout the surgical procedure without requiring complex timing circuits or communication interfaces.

Inventive Principle:
Principle #20Continuity of useful action

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 solution provides accurate, contamination-resistant, and lightweight tracking without the need for external power sources, reducing surgeon fatigue and instrument deformation, while maintaining tracking accuracy and simplicity.

Implementation Method 1

The electrical circuit comprises an arrangement of more than two infrared light emitting diodes, IR-LEDs

Methodology Applied
Scientific EffectLight emitting diode: Light Emitting Diode

Implementation Method 2

The electrical circuit further comprises a battery that is a single button cell, wherein the battery is configured to provide power to operate all of the IR-LEDs of the arrangement

Methodology Applied
Scientific EffectBattery: Battery (electricity)

Data Source

PatentEP3593750B1Tracker for a surgical navigation system
Publication Date: 2026.02.25 STRYKER EUROPEAN OPERATIONS HOLDINGS LLC
  • EP3593750B1 patent drawingFigure 1A
  • EP3593750B1 patent drawingFigure 1B
  • EP3593750B1 patent drawingFigure 2

AI summary

A tracker for a surgical navigation system and a surgical navigation system are provided. The tracker comprises a carrier and an electrical circuit disposed on the carrier. The electrical circuit comprises an arrangement of more than two infrared light emitting diodes, IR-LEDs, wherein the arrangement has no rotational symmetry, and a battery or a wireless power reception device configured to receive power wirelessly, wherein the battery or the wireless power reception device is configured to provide power to operate at least one IR-LED of the arrangement. The electrical circuit is configured to limit a current for at least one of the at least one IR-LED to not exceed 15mA.