RFID Surgical Item Tracking for Accurate Retained Item Detection

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Solution Overview

Problem

Existing inventory systems for surgical items are inadequate as they either have physically large components that interfere with procedures or suffer from degraded detection performance in the presence of dielectric and conductive materials, leading to potential retention issues and unintended medical consequences.

Innovation Solution

An RFID-based system with an antenna over the surgical site, using triangulation to determine the position and velocity of RFID tags affixed to surgical items, providing real-time detection and inventory management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RFID tags are attached to surgical items for tracking, then detection capability is improved, but the physical size of the tag may interfere with surgical procedures

Engineering Contradiction:

Improvedetection capabilityVSAvoidphysical size of RFID tag

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The RFID tag is integrated within or attached to the surgical item in a nested configuration, where the tag components are contained within the surgical instrument housing or attached to the handle portion, minimizing external protrusion and interference with the surgical function while maintaining detection capability

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The RFID tag uses thin film or flexible substrate materials that allow the tag to conform to the surgical item without adding significant bulk, enabling the tag to be attached to curved or irregularly shaped instruments while maintaining a low profile that does not interfere with surgical procedures

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If RFID detection is performed in the presence of dielectric and conductive materials, then surgical item tracking is enabled, but detection performance degrades rapidly

Engineering Contradiction:

Improvesurgical item trackingVSAvoiddetection performance

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system uses an intermediary reference signal or calibration procedure that accounts for the effects of dielectric and conductive materials in the surgical environment, allowing the RFID detection system to compensate for signal degradation and maintain accurate tracking performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The RFID detection system dynamically adjusts operational parameters such as frequency, power output, or signal processing algorithms based on the detected presence of dielectric or conductive materials, optimizing detection performance under varying surgical conditions

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If additional detection equipment is added to improve surgical item detection, then detection accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The RFID transceiver system is designed to perform multiple functions including detection, tracking, and inventory management using a single integrated platform, eliminating the need for separate specialized equipment and reducing overall system complexity while maintaining high detection accuracy

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The detection, tracking, and inventory management functions are merged into a single RFID-based system that uses shared hardware and software resources, reducing device complexity compared to having separate systems for each function while maintaining comprehensive surgical item monitoring capability

Inventive Principle:

Principle #5Merging (Combining)

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 accurate detection and tracking of surgical items, ensuring they are not left in the patient, with automated counting and real-time feedback to clinicians, reducing the need for additional surgeries and medical complications.

Implementation Method 1

The plurality of RFID transceivers is configured to generate an energizing signal for the RFID tag and to receive the return signal transmitted by the RFID tag

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

determine an initial position of the surgical item based on the first return signal by triangulation

Methodology Applied

Scientific EffectTriangulation:

Data Source

PatentUS12502230B2Inventory systems and methods for retained surgical item detection

Publication Date: 2025.12.23 COVIDIEN LP

AI summary

An inventory system configured for detecting and counting surgical items includes an RFID tag affixed to a surgical item, a plurality of RFID transceivers, a processor, and a memory. The memory includes instructions stored in the memory, which when executed by the processor cause the system to: energize the RFID tag; receive a first return signal from the RFID tag by the plurality of RFID transceivers; determine an initial position of the surgical item; receive a second return signal from the RFID tag by the plurality of RFID transceivers; determine a last known position of the surgical item and a velocity of the RFID tag; determine a difference between the last known position of the RFID tag and the initial position of the RFID tag; and determine a count of the surgical item based on the determined difference and the velocity and/or direction of the RFID tag.