RLC Coil Position Sensing for Medical Needle Advancement

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Solution Overview

Problem

Existing medical devices lack effective methods to determine the precise longitudinal position of a second medical device within a first medical device during procedures, which can lead to inefficiencies and potential patient safety risks.

Innovation Solution

An RLC circuit is integrated into a medical device system, comprising a coil and magnetic core, to monitor the output voltage changes as a second device is advanced through a lumen, providing real-time indicators of its position relative to the first device, using a processor to generate visual or graphical outputs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an RLC circuit with coil and magnetic core is integrated into the medical device system to monitor output voltage changes, then the measurement precision of the longitudinal position is improved, but the device complexity increases

Engineering Contradiction:

Improvelongitudinal position measurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical position indication methods with an electrical measurement system. An RLC circuit with a coil and magnetic core is used to detect changes in inductance caused by the movement of the second medical device through the lumen. The output voltage of the RLC circuit serves as an indicator of the longitudinal position, eliminating the need for complex mechanical positioning mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary substance - a magnetic core - that mediates between the mechanical movement of the second medical device and the electrical detection system. The magnetic core changes its position relative to the coil as the second device moves through the lumen, converting mechanical displacement into detectable inductance changes without direct mechanical coupling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If real-time position monitoring is implemented using an RLC circuit, then the reliability of the medical procedure is improved, but the use of energy increases

Engineering Contradiction:

Improveprocedure reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic action by using an alternating excitation voltage source to drive the RLC circuit. The circuit is excited at a resonant frequency, allowing it to respond periodically to the movement of the second medical device. This periodic excitation enables continuous monitoring while minimizing energy consumption compared to continuous DC monitoring.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent utilizes the phase transition characteristics of the RLC circuit at resonance. By operating the circuit at its resonant frequency, the system achieves maximum sensitivity to inductance changes with minimal energy input. The phase relationship between the excitation voltage and current changes predictably with position, providing reliable detection with efficient energy use.

Inventive Principle:

Principle #36Phase transitions

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

Enhances the ease of use and safety of medical procedures by accurately determining the position of the second device, ensuring timely and controlled deployment, particularly in transseptal perforation procedures.

Implementation Method 1

an inductor including a coil that is supported by the first medical device and wound around the lumen. As the needle is advanced through the lumen, an output voltage of the RLC circuit is an indicator of a longitudinal position of the needle with respect to the elongate member

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

the inductor further includes a magnetic core positioned radially inwardly of the coil and supported by the first medical device. The magnetic core can be embedded in the sidewall

Methodology Applied

Scientific EffectMagnetic Core Effect: Ferromagnetism

Data Source

PatentUS20250205458A1Methods for determining a position of a first medical device with respect to a second medical device, and related systems and medical devices

Publication Date: 2025.06.26 BOSTON SCI MEDICAL DEVICE LTD

AI summary

A system of medical devices includes a first medical device, a second medical device, an RLC circuit, a processor, and an output device. The first medical device includes an elongate member having a lumen. The second medical device includes a needle advanceable through the lumen. The RLC circuit includes an excitation voltage source, a resistor, a capacitor, an inductor, and an output voltage sensor. The inductor includes a coil that is supported by the first medical device and wound around the lumen. As the needle is advanced through the lumen, an output voltage of the RLC circuit is an indicator of a longitudinal position of the needle with respect to the elongate member. The voltage sensor is configured to sense the output voltage, and the processor and output device are configured to generate an output that is an indicator of the longitudinal position of the needle.