Dual-Temperature Medical Ablation System for Reduced Stray Heating

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Solution Overview

Problem

Endoluminal ablation systems face challenges in managing heat generated during the ablation process, leading to undesired damage to adjacent tissues and organs due to the heat sink effect of blood flow and the limited power capacity of RF electrodes, which restricts their effectiveness and application.

Innovation Solution

A dual-temperature ablation system that preheats the vessel or tissue to a lower temperature before applying higher ablation temperatures, reducing the energy required for ablation and minimizing collateral tissue damage by using a resistive heating device and an electrical ablation element, with a control unit to manage the heating process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RF ablation is used to heat blood plasma or tissue to elevated temperatures for vessel closure or tissue destruction, then ablation effectiveness is improved, but collateral damage to adjacent tissues, nerves or organs increases

Engineering Contradiction:
Improveablation effectivenessVSAvoidcollateral tissue damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a pre-heating element that heats the vessel or tissue to a first temperature before the ablation element is activated. This preliminary heating action reduces the temperature differential required during ablation, thereby achieving the desired ablation effect while reducing the risk of collateral damage to adjacent structures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs two distinct temperature parameters: a first temperature for pre-heating and a second temperature for ablation. By controlling and separating these temperature parameters, the system optimizes the ablation process to achieve effective tissue destruction while minimizing damage to surrounding healthy tissues, nerves, or organs.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If higher power is applied to the RF electrode to overcome the heat sink effect of blood flow, then ablation effectiveness is improved, but the electrode exceeds its power capacity and causes charring

Engineering Contradiction:
Improveablation effectivenessVSAvoidelectrode charring
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The pre-heating element is activated before the ablation element to raise the baseline temperature of the blood plasma and tissue. This preliminary thermal preparation reduces the additional energy required from the ablation electrode, preventing it from exceeding its power capacity and causing charring while still achieving effective ablation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pre-heating element acts as an intermediary that prepares the thermal environment before the ablation element operates. By introducing this intermediate heating step, the system reduces the direct energy demand on the ablation electrode, thereby avoiding charring while maintaining ablation effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single-temperature ablation system is used, then device complexity is reduced, but the energy required for successful ablation increases due to the heat sink effect

Engineering Contradiction:
Improvesystem simplicityVSAvoidenergy required for ablation
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The ablation system is segmented into two functional elements: a pre-heating element and an ablation element. This segmentation allows the pre-heating element to address the heat sink effect by raising the baseline temperature, thereby reducing the energy required by the ablation element while maintaining manageable overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pre-heating element performs a preliminary thermal preparation function that reduces the energy burden on the ablation element. This preliminary action effectively addresses the heat sink effect of blood flow without requiring a substantial increase in the ablation element's power output.

Inventive Principle:
Principle #10Preliminary 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 dual-temperature approach reduces the energy needed for ablation, avoids exceeding the electrode's power capacity, and minimizes collateral tissue damage, allowing for more controlled and effective vessel closure or tissue treatment.

Implementation Method 1

A technique which has been considered suitable is RF ablation, in which an electrical terminal is fed endoluminally into the vessel and an electrical pulse at RF frequencies applied through the electrical terminal. The conductivity of blood and/or the vessel tissues causes localised heating

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

an electrical pulse at RF frequencies applied through the electrical terminal. The conductivity of blood and/or the vessel tissues causes localised heating, which can be used to cause damage to the tissue (intima) of the vessel wall, resulting in vessel contraction

Methodology Applied
Scientific EffectRF ablation heating: Joule Heating

Implementation Method 3

In other devices RF ablation heats the surrounding blood, causing this to coagulate around the electrical terminal, forming a blood clot which blocks the vessel

Methodology Applied
Scientific EffectBlood coagulation: Coagulation

Data Source

PatentEP3072468B1Medical ablation system with reduced stray heating
Publication Date: 2019.09.18 COOK MEDICAL TECHNOLOGIES LLC
  • EP3072468B1 patent drawingFigure 1~3
  • EP3072468B1 patent drawingFigure 4~5
  • EP3072468B1 patent drawingFigure 6

AI summary

A medical ablation system (10) includes an elongate element (12) to be inserted endoluminally into a patient's vessel (140) and includes at its distal end (14) a pre-heating element (22) and an ablation element (20, 210, 310, 410). The system (10) provides pre-heating of, for example, blood to a first threshold temperature above body temperature but below ablation temperature; and then a second heating stage provided by the ablation element (20, 210, 310, 410). Preheating reduces the amount of energy required to effect ablation, resulting in more focussed embolization with a higher proportion of energy delivered to the area in a more controlled manner. The arrangement can reduce the amount of damage to surrounding tissues and organs.