Inferred Temperature Monitoring for Irrigated Ablation
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Solution Overview
Problem
Conventional RF ablation techniques face limitations in treating tissue volume due to maximum heating occurring at the interface between the instrument and tissue, leading to tissue instability and potential steam pops. Additionally, existing methods for monitoring tissue temperature at remote locations are complex and costly, making it difficult to prevent overheating.
Innovation Solution
The method involves positioning an elongate body with an ablation element and a temperature sensor proximate to the tissue, delivering ablative energy and liquid, and then pausing this delivery to monitor the temperature of the ablation element. Based on the temperature change during the pause, the method infers the temperature of tissue remote from the instrument, allowing for effective monitoring without additional sensors or structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is positioned at a remote location in tissue using tines or extending structures, then tissue temperature at remote locations can be detected, but the instrument's complexity and cost increase
Solution Approach 1:
The patent uses the ablation element itself as an intermediary thermal conductor to transmit temperature information from remote tissue locations back to the temperature sensor at the instrument base. By establishing thermal contact between the ablation element and remote tissue, then using the ablation element as a heat transfer medium, the system can infer remote tissue temperature without placing sensors directly in the tissue.
Solution Approach 2:
The patent replaces the mechanical approach of physically extending sensors into tissue with a thermal field-based approach. Instead of mechanically positioning a sensor at the remote location, the system uses thermal conduction through the ablation element to transmit temperature information, substituting a mechanical sensor positioning system with a thermal field measurement system.
2Temperature
If liquid irrigation is used to regulate ablation element temperature, then maximum heating at the instrument-tissue interface is prevented, but maximum heating can occur at remote tissue locations that cannot be detected
Solution Approach 1:
The patent establishes a feedback loop where the temperature sensor continuously monitors the ablation element temperature, and this information is used to infer remote tissue temperature. The system uses the thermal coupling between the ablation element and remote tissue to create an indirect feedback mechanism that provides information about remote tissue conditions without direct sensing.
Solution Approach 2:
The ablation element serves multiple functions: it delivers ablative energy to the tissue, it acts as a thermal conductor to transmit temperature information from remote locations, and it serves as the sensing element itself. This multi-functionality eliminates the need for separate sensing structures while providing remote temperature monitoring capability.
3Device complexity
If conventional RF ablation is used without irrigation, then simpler instrumentation is required, but maximum heating occurs at the interface reducing treatable tissue volume
Solution Approach 1:
The system uses the ablation element's own thermal properties and its thermal coupling with the tissue to provide self-diagnosis of remote tissue temperature. The ablation element serves its primary function of energy delivery while simultaneously providing temperature monitoring capability through its thermal interaction with the tissue, eliminating the need for separate monitoring systems.
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 approach enables monitoring of tissue temperature at remote locations without increasing instrument complexity or cost, effectively preventing overheating and reducing the risk of steam pops during ablation therapy.
Implementation Method 1
Radio frequency (RF) ablation, for example, can be effected by placing one or more electrodes against or into tissue to be treated and passing high frequency electrical current into the tissue
Implementation Method 2
In irrigated ablation therapy, liquid can be circulated past the ablation element, such as the above-mentioned one or more electrodes, to prevent the above-described maximum heating at the interface between the instrument and tissue
Implementation Method 3
a temperature sensor, such as a thermocouple, can be used to monitor a temperature of the ablation element directly
Data Source
AI summary
Methods and systems utilizing inferred maximum temperature monitoring for irrigated ablation therapy are described herein. In one embodiment, a method for ablating tissue includes positioning an elongate body proximate to tissue, where the elongate body includes an ablation element and at least one temperature sensor coupled thereto. The method can include simultaneously delivering ablative energy to the tissue through the ablation element and liquid through the elongate body. The method can further include pausing delivery of ablative energy and liquid, as well as sensing a temperature of the ablation element while delivery of ablative energy and liquid is paused. The method can further include any of terminating delivery of ablative energy and liquid and resuming delivery of ablative energy and liquid based on a comparison of the sensed temperature to a reference temperature.