Electrosurgical Apparatus Waveguide Isolator RF Isolation
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Solution Overview
Problem
Electrosurgical apparatuses face challenges in efficiently cutting and coagulating fatty tissue due to reduced efficiency in fatty tissue, leading to increased energy requirements and undesirable tissue appearance during procedures.
Innovation Solution
The use of a waveguide isolator at the junction between the microwave and signal combiner to prevent RF power from entering the microwave channel, reducing capacitive coupling and enhancing electrical safety, while maintaining high microwave power transmission and withstanding voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF energy is used to cut and coagulate tissue, then cutting and coagulation functions are achieved, but efficiency is reduced when fatty tissue is present due to fewer ionic constituents
Solution Approach 1:
The patent divides the electromagnetic energy treatment into two separate channels: an RF channel for cutting and a microwave channel for coagulation. This segmentation allows each channel to be optimized for its specific function, with the microwave channel providing additional heating capability that overcomes the limitation of RF energy in fatty tissue with fewer ionic constituents.
Solution Approach 2:
The patent employs a composite electromagnetic energy delivery system that combines RF and microwave energy through a signal combiner. The probe delivers both RF and microwave energy simultaneously to the tissue, creating a composite thermal effect that improves efficiency in fatty tissue where RF alone is less effective.
2Device complexity
If RF and microwave channels are combined in a single feed structure, then device complexity is reduced, but capacitive coupling between channels causes safety issues
Solution Approach 1:
The patent introduces a waveguide isolator as an intermediary component in the microwave channel between the signal combiner and the probe. This isolator acts as a barrier that prevents RF energy from the RF channel from coupling capacitively into the microwave channel, while still allowing microwave energy to pass through to the probe.
Solution Approach 2:
The patent extracts the harmful capacitive coupling effect by removing the direct electrical connection between the RF and microwave channels at the probe interface. The waveguide isolator separates the two channels electrically, taking out the source of the capacitive coupling problem while maintaining the benefits of a combined feed structure.
3Productivity
If microwave power is increased to improve coagulation in fatty tissue, then coagulation effectiveness increases, but unwanted heating and safety risks increase
Solution Approach 1:
The patent implements a control system that monitors the impedance and power delivery to the probe and adjusts the microwave power accordingly. This feedback mechanism ensures that sufficient power is delivered to achieve effective coagulation in fatty tissue while preventing excessive power delivery that could cause unwanted heating or safety issues.
Solution Approach 2:
The patent uses dynamic control of the microwave power delivery based on real-time detection of tissue conditions. The system can adjust the microwave power level during the procedure to match the actual tissue impedance and thermal conditions, optimizing coagulation effectiveness while minimizing the risk of overheating.
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 effectively isolates the microwave channel from RF power, preventing unwanted capacitive coupling and ensuring safe operation, thereby improving the apparatus's ability to efficiently cut and coagulate tissues, including fatty tissues, while meeting electrical safety standards.
Implementation Method 1
a waveguide isolator connected to isolate the separate signal pathway on the microwave channel from the RF electromagnetic radiation
Implementation Method 2
a capacitive structure between the ground conductor of the output from the combining circuit and the conductive input section of the waveguide isolator, the capacitive structure being arranged to inhibit coupling of the RF electromagnetic energy
Implementation Method 3
a RF signal generator for generating RF electromagnetic (EM) radiation having a first frequency
Implementation Method 4
a microwave signal generator for generating microwave EM radiation having a second frequency that is higher than the first frequency
Implementation Method 5
a probe arranged to deliver the RF EM radiation and the microwave EM radiation separately or simultaneously from a distal end thereof
Data Source
AI summary
An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.