Cooled Ablation Probe with External Temperature Sensor
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Solution Overview
Problem
Existing medical devices for lesioning target tissue using radiofrequency energy face challenges in accurately monitoring tissue temperature and efficiently delivering ablative energy while minimizing tissue charring and cavitation.
Innovation Solution
The development of a probe with an elongate member featuring a cooled active electrode and a temperature sensor positioned proximally of the distal end to measure the temperature in the heat affected zone, allowing for real-time monitoring and adjustment of ablative energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If radiofrequency energy is delivered to target tissue to form a lesion, then the thermal ablation zone size increases, but tissue charring and cavitation occur due to excessive temperature
Solution Approach 1:
The active electrode is divided into multiple cooled sections with independent cooling fluid delivery, allowing different regions to be cooled to different extents. This segmentation enables precise temperature control across the electrode surface, preventing localized charring while maintaining effective ablation zones
Solution Approach 2:
A cooling fluid is introduced as an intermediary substance between the radiofrequency energy source and the target tissue. The cooling fluid absorbs excess heat from the active electrode, mediating the thermal interaction to prevent harmful temperature spikes that cause charring and cavitation
2Measurement precision
If a temperature sensor is positioned at the distal end of the probe to monitor tissue temperature, then real-time temperature feedback is achieved, but the cooled section interferes with accurate temperature measurement
Solution Approach 1:
The temperature sensor is extracted from the cooled section and repositioned to contact only the non-cooled portion of the active electrode. This separation removes the interfering cooling effect from the measurement location, allowing accurate temperature monitoring of the tissue-heating portion without contamination from the cooling fluid
Solution Approach 2:
The active electrode is designed with non-uniform cooling characteristics, creating distinct cooled and non-cooled regions with different thermal properties. The temperature sensor is strategically positioned to contact only the non-cooled region, utilizing the local quality difference to achieve accurate temperature measurement independent of the cooling system
3Reliability
If cooling fluid is delivered through the entire active electrode to prevent charring, then temperature control improves, but the complexity of the fluid delivery system increases
Solution Approach 1:
The cooling fluid delivery system is segmented into multiple independent lumens, each supplying cooling fluid to specific sections of the active electrode. This modular segmentation allows for simplified control of each cooling zone while maintaining overall temperature control reliability across the entire electrode
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 controlled and effective lesion formation by accurately monitoring tissue temperature and optimizing energy delivery, reducing the risk of tissue damage and improving the size and consistency of the thermal ablation zone.
Implementation Method 1
The first active electrode includes a cooled section that is coolable by receipt of a cooling fluid delivered through the elongate member
Implementation Method 2
at least a first temperature sensor is positioned external of the elongate member to measure a temperature in a heat affected zone of the target tissue
Implementation Method 3
Each of the probe assemblies has an electrically conductive energy delivery device electrically coupled to the energy source... the energy source delivers energy to the spinal tissue through the energy delivery devices in a bipolar mode that concentrates delivered energy between the energy delivery devices to create a lesion
Data Source
AI summary
A probe for forming a lesion in a target tissue includes an elongate member extending longitudinally between a proximal end and a distal end. The elongate member has an active electrode proximate the distal end for delivering ablative energy to the target tissue, and an electrically insulated section proximal of the active electrode. The active electrode includes a cooled section that is coolable by receipt of a cooling fluid delivered through the elongate member. At least a first temperature sensor is positioned external of the elongate member to measure a temperature in a heat affected zone of the target tissue. The first temperature sensor is positioned proximally of the distal end and is spaced from the cooled section.