Electrosurgical Generator Tissue Impedance Measurement
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Solution Overview
Problem
Current electrosurgical systems lack the ability to consistently and effectively measure tissue properties during sealing procedures, leading to inefficiencies in energy application and tissue treatment.
Innovation Solution
An electrosurgical system that includes a generator capable of supplying an initial interrogatory signal at constant voltage to tissue, continuously monitoring tissue impedance response, and using a microprocessor to generate treatment parameters based on initial impedance, impedance drop, impedance minimum, and impedance rise, allowing for adaptive energy application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrosurgical systems apply fixed energy parameters to tissue, then the device complexity is reduced, but the tissue sealing consistency and effectiveness deteriorate
Solution Approach 1:
The system performs preliminary impedance measurement before applying electrosurgical energy to characterize the tissue properties. This preliminary action allows the system to adapt energy parameters to the specific tissue being treated, improving sealing consistency without requiring complex real-time adjustments during energy delivery
Solution Approach 2:
The system measures tissue impedance during and after energy application, using this feedback information to determine when sealing is complete. The impedance rise detection provides an automatic endpoint criterion that improves reliability while keeping the control logic manageable through clear threshold-based decision-making
2Reliability
If the generator applies high energy to tissue to ensure effective sealing, then the tissue treatment effectiveness is improved, but the risk of thermal damage to surrounding tissue increases
Solution Approach 1:
The system dynamically adjusts energy delivery based on real-time impedance measurements. By monitoring impedance changes during energy application, the system can terminate delivery when sealing is achieved, preventing excessive energy application that would cause thermal damage to surrounding tissue
Solution Approach 2:
The system changes energy delivery parameters based on tissue impedance characteristics. Different tissue types exhibit different impedance profiles, and the system adapts energy parameters accordingly to achieve effective sealing at lower energy levels, reducing the risk of thermal spread to adjacent structures
3Measurement precision
If the system uses complex real-time impedance analysis to determine treatment parameters, then the tissue sealing precision is improved, but the measurement and detection difficulty increases
Solution Approach 1:
The impedance measurement process is segmented into distinct phases: initial impedance measurement before energy delivery, impedance monitoring during energy delivery, and impedance rise detection after energy delivery. This segmentation simplifies the measurement complexity by breaking down the continuous monitoring task into manageable discrete events with clear decision points
Solution Approach 2:
The system replaces complex mechanical tissue assessment methods with electrical impedance measurement. Instead of relying on visual inspection or tactile feedback, the system uses electrical properties to characterize tissue and determine sealing completion, providing more precise and objective measurement while simplifying the operator's task
4Productivity
If the electrosurgical system continuously monitors tissue impedance throughout the procedure, then the productivity is improved through automated control, but the energy consumption increases
Solution Approach 1:
Impedance monitoring is performed periodically at key stages rather than continuously throughout the entire procedure. The system measures initial impedance before energy delivery, monitors during delivery, and detects impedance rise after delivery to determine completion. This periodic approach maintains automated control and productivity while minimizing unnecessary energy consumption from continuous monitoring
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
Enables precise and consistent tissue sealing by accurately determining tissue properties and adjusting energy parameters in real-time, improving the efficiency and effectiveness of electrosurgical procedures.
Implementation Method 1
supplying an initial interrogatory signal at constant voltage to tissue and measuring initial tissue impedance response
Implementation Method 2
sensor circuitry adapted to continuously monitor tissue impedance response
Implementation Method 3
application of high radio frequency electrical current to a surgical site to cut, ablate, coagulate, cauterize, desiccate or seal tissue
Implementation Method 4
application of high radio frequency electrical current to a surgical site
Data Source
AI summary
An electrosurgical system and method are disclosed. The system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The generator is further adapted to supply an electrical signal having at least one substantially constant value to tissue to determine initial tissue impedance response. The generator includes sensor circuitry adapted to continuously monitor initial tissue impedance response, wherein the initial tissue impedance response includes one of an initial impedance, an impedance drop, an impedance minimum and a first impedance rise. The generator also includes a microprocessor adapted to generate at least one tissue parameter based as a function of the initial impedance, the impedance drop, the impedance minimum and the first impedance rise. The system also includes an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue for treatment.