Impedance Mediated Electrosurgical Power Delivery Control
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Solution Overview
Problem
Existing electrosurgical systems face challenges in delivering precise amounts of energy for tissue sealing while minimizing damage to surrounding tissue, as tissue impedance increases during energy absorption, requiring a method to control energy delivery based on real-time impedance feedback.
Innovation Solution
The system delivers energy in a series of pulses with adjustable profiles, using sensed tissue impedance to compare against preset threshold values for RF setpoint, cumulative time, and energy cutback, allowing for dynamic adjustment of energy delivery, including ceasing, increasing, or cutting back energy based on impedance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high RF electrical current is applied to seal tissue, then sealing effect is achieved, but excess energy may damage surrounding tissue
Solution Approach 1:
The system continuously monitors tissue impedance during energy delivery and uses this feedback to dynamically adjust the RF power output. As tissue impedance increases during sealing, the system detects this change and reduces energy delivery accordingly, preventing excess energy from damaging surrounding tissue while ensuring reliable sealing at the target site
Solution Approach 2:
The electrosurgical system transitions from static, pre-set power delivery to dynamic, real-time power modulation based on measured tissue impedance. The RF power level is continuously adjusted during the sealing process to match the changing electrical properties of the tissue, optimizing both sealing effectiveness and safety
2Object-affected harmful factors
If precise energy control is implemented based on impedance feedback, then tissue damage is minimized, but system complexity increases
Solution Approach 1:
The system incorporates real-time impedance sensing and feedback control mechanisms that automatically adjust RF power delivery based on measured tissue properties. This closed-loop control minimizes tissue damage by preventing excess energy delivery while maintaining relatively straightforward system architecture through automated feedback rather than complex manual control 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 ensures efficient tissue processing by matching energy delivery to tissue absorption rates, minimizing excess energy spread and achieving optimal sealing while preventing tissue damage.
Implementation Method 1
Bipolar electrosurgical instruments apply high radiofrequency (RF) electrical current to a surgical site to cut, ablate, or coagulate tissue
Implementation Method 2
As tissue absorbs energy, such as radiofrequency energy, its impedance of radiofrequency energy increases
Data Source
AI summary
In a method of controlling electrosurgical power delivery based on a comparison of sensed tissue impedance to various impedance threshold values, energy is delivered to tissue in a sealing cycle as a series of pulses. An initial pulse has a profile with a preset energy starting value that increases at a ramping rate to a preset end value. Sensed impedance data are monitored throughout each pulse and compared to an impedance threshold value for RF setpoint, an impedance threshold value for cumulative time, and an impedance threshold value for energy cutback. Based on sensed impedance during a pulse, the profile of a subsequent pulse can be modified. In a high impedance event that reflects low tissue presence, energy may be cutback. A sealing cycle is stopped when a cumulative amount of time with an impedance value over the impedance cumulative time threshold value reaches a sealing cycle duration limit.