Thermal Feedback Control for Fluid-Cooled Antenna Assembly

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Solution Overview

Problem

Existing electrosurgical devices face challenges in maintaining precise temperature control during tissue ablation procedures, as they often experience overheating issues due to inadequate cooling, leading to tissue desiccation and char, which impede treatment effectiveness and increase the risk of device failure.

Innovation Solution

A thermal-feedback-controlled system that regulates the fluid flow to a fluid-cooled antenna assembly using temperature and flow sensors, adjusting the coolant flow rate to maintain optimal temperatures and prevent overheating, thereby ensuring effective tissue ablation while protecting the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electromagnetic energy is applied to heat tissue for ablation, then tumor cells are destroyed, but surrounding healthy tissue may be damaged due to excessive heating

Engineering Contradiction:
Improvetumor cell destruction effectivenessVSAvoiddamage to surrounding healthy tissue
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system employs temperature sensors that continuously monitor tissue temperature during ablation and feed this information back to the control system. The controller adjusts electromagnetic energy delivery in real-time based on temperature feedback, maintaining tissue temperature within the therapeutic window (41-45°C) to destroy tumor cells while preventing overheating of surrounding healthy tissue

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes operational parameters including electromagnetic energy power levels, pulse duration, and cooling fluid flow rate based on real-time temperature measurements. This allows precise control of thermal dose delivered to tissue, enabling selective tumor cell destruction while protecting adjacent healthy structures

Inventive Principle:
Principle #35Parameter changes

2Reliability

If cooling fluid flow is increased to prevent overheating, then device components are protected from thermal damage, but treatment efficiency may be reduced

Engineering Contradiction:
Improvedevice component thermal protectionVSAvoidtreatment efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts cooling fluid flow rate based on real-time temperature measurements from sensors monitoring both tissue and device component temperatures. The control system optimizes cooling intensity to provide sufficient thermal protection of the antenna assembly while minimizing interference with the ablation heating process, thereby maintaining treatment efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system maintains continuous cooling fluid flow throughout the ablation procedure, ensuring uninterrupted thermal management of the antenna assembly. This continuous cooling allows sustained high-power electromagnetic energy delivery without thermal damage to device components, thereby maintaining consistent treatment efficiency throughout the procedure

Inventive Principle:
Principle #20Continuity of useful action

3Object-affected harmful factors

If temperature monitoring is continuously performed to maintain precise temperature control, then tissue damage is minimized, but system complexity increases

Engineering Contradiction:
Improvetissue desiccation and charVSAvoidthermal feedback control system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system incorporates temperature sensors positioned to monitor tissue temperature during ablation. The sensor signals are fed back to a controller that automatically adjusts electromagnetic energy delivery to maintain temperature within the therapeutic window, preventing tissue desiccation and charring while minimizing system complexity through automated control

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system employs self-regulating thermal control where temperature sensors monitor tissue conditions and the control algorithm automatically adjusts energy delivery without requiring constant manual intervention. This self-service approach minimizes tissue damage while keeping the operational interface simple for the operator

Inventive Principle:
Principle #25Self-service

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 enables more precise temperature control, reducing tissue damage and device failure risks by dynamically adjusting coolant flow based on real-time temperature feedback, ensuring efficient and safe ablation procedures.

Implementation Method 1

a fluid-cooled antenna assembly

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a temperature sensor adapted to provide a signal indicative of a temperature of the antenna assembly

Methodology Applied
Scientific EffectThermal detection: Thermocouple

Implementation Method 3

a flow sensor adapted to provide a signal indicative of a rate of fluid flow to the antenna assembly

Methodology Applied
Scientific EffectFlow measurement: Venturi Effect

Implementation Method 4

a feedback control system adapted to provide a thermal-feedback-controlled rate of fluid flow to the antenna assembly when energized

Methodology Applied
Scientific EffectThermal feedback control: Feedback

Data Source

PatentEP2671529B1Systems for thermal-feedback-controlled rate of fluid flow to fluid-cooled antenna assembly
Publication Date: 2016.11.23 COVIDIEN LP
  • EP2671529B1 patent drawingFigure 1
  • EP2671529B1 patent drawingFigure 2
  • EP2671529B1 patent drawingFigure 3

AI summary

An electrosurgical system includes an electrosurgical device adapted to direct energy to tissue, one or more temperature sensors associated with the electrosurgical device, a fluid-flow path leading to the electrosurgical device, and a flow-control device disposed in fluid communication with the fluid-flow path. The system also includes a processor unit communicatively-coupled to the one or more temperature sensors and communicatively-coupled to the flow-control device. The processor unit is configured to control the flow-control device based on determination of a desired fluid-flow rate using one or more electrical signals outputted from the one or more temperature sensors.