Virtually-Shorted Electrodes for Uniform IRE Tissue Ablation
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Solution Overview
Problem
Existing irreversible electroporation (IRE) procedures face challenges in achieving uniform electroporation across larger tissue areas due to local impedance differences and contact impedance variations between electrodes and tissue, leading to non-uniform voltage and phase waveforms, which can result in unsatisfactory ablation effects.
Innovation Solution
A medical apparatus and method that includes a probe with a distal assembly of electrodes, an electrical signal generator, and a controller to apply biphasic electrical pulses while measuring and adjusting time-varying voltage differences between electrodes to ensure that voltage differences do not exceed a predetermined threshold, effectively creating a 'virtual shorting' of electrodes to achieve uniform electroporation across a larger area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple electrodes are used to treat larger tissue areas, then treatment coverage is improved, but voltage and phase uniformity deteriorates due to local impedance differences
Solution Approach 1:
The system actively controls the voltage at each electrode to maintain equipotential conditions across the electrode array. By measuring the actual voltage at each electrode and applying compensating adjustments, the system ensures that all electrodes operate at the same potential level, eliminating the voltage non-uniformity that would otherwise occur when treating larger tissue areas with multiple electrodes.
Solution Approach 2:
The system incorporates real-time voltage measurement and feedback control for each electrode. The controller continuously monitors the voltage at each electrode and adjusts the applied voltage accordingly to maintain uniformity. This closed-loop feedback mechanism compensates for local impedance differences and contact variations, ensuring consistent voltage distribution across all electrodes during treatment of larger tissue areas.
2Productivity
If electrode voltage is increased to improve ablation effectiveness, then electroporation efficiency is improved, but non-uniform current flow paths increase causing unsatisfactory ablation
Solution Approach 1:
The system applies local quality control by independently adjusting the voltage at each electrode based on its specific local conditions. Rather than applying a uniform voltage to all electrodes, the system tailors the voltage application to each local site, compensating for variations in tissue impedance and electrode-tissue contact. This ensures that each electrode contributes uniformly to the ablation process, maintaining ablation uniformity even at high voltage levels that improve overall ablation efficiency.
3Ease of operation
If bipolar mode is used between electrode groups, then current flow control is improved, but voltage difference control becomes more complex
Solution Approach 1:
The system uses feedback control to simplify bipolar mode operation. By continuously monitoring the actual voltage at each electrode and automatically adjusting the applied voltage to maintain the desired voltage difference between electrode groups, the system provides intuitive current flow control without requiring the operator to manually manage the complex voltage relationships. The feedback loop handles the complexity internally, maintaining simple operation for the user.
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 ensures consistent and efficient electroporation by maintaining uniform voltage and phase waveforms across electrodes, improving ablation precision and effectiveness by preventing unsatisfactory current flow paths and enhancing tissue treatment outcomes.
Implementation Method 1
Irreversible electroporation (IRE) is a soft tissue ablation technique that applies short pulses of strong electrical fields to create permanent and hence lethal nanopores in the cell membrane
Implementation Method 2
A controller is coupled to measure time-varying voltage differences between the electrodes in the at least one group
Data Source
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AI summary
A medical apparatus includes a probe, which includes an insertion tube configured for insertion into a body cavity of a patient, and a distal assembly, which is connected distally to the insertion tube and comprises a plurality of electrodes, which are configured to contact tissue within the body cavity. An electrical signal generator is configured to apply biphasic electrical pulses simultaneously to at least one group of two or more of the electrodes with energy sufficient to irreversibly electroporate the tissue contacted by the electrodes in the at least one group. A controller is coupled to measure time-varying voltage differences between the electrodes in the at least one group and to adjust the biphasic electrical pulses applied to the electrodes in the at least one group so that the voltage differences do not exceed a predetermined threshold at any time during application of the biphasic electrical pulses.