Circuit Topologies for Combined RF and Ultrasonic Generator Signals
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Solution Overview
Problem
Current surgical instruments lack the ability to fully control and customize the functions of ultrasonic and electrosurgical systems, leading to inefficiencies in surgical procedures.
Innovation Solution
A mixed energy surgical instrument that utilizes both ultrasonic and RF energy modalities, with multiple circuit topologies that enable a generator to drive both energies into tissue simultaneously or by switching between them, using high frequency filters, bandstop filters, resonators, and solid state switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a generator delivers both RF and ultrasonic energies through a single output, then device versatility and surgical customization are improved, but circuit complexity and signal interference increase
Solution Approach 1:
The patent divides the combined RF/ultrasonic signal into separate frequency components using bandpass filters. Each filter segment isolates specific frequency ranges (e.g., 20-100 kHz for ultrasonic, higher frequencies for RF), allowing independent delivery to tissue without mutual interference. This segmentation resolves the contradiction by maintaining signal purity while enabling dual-energy versatility from a single generator output.
Solution Approach 2:
The patent introduces resonators as intermediary components tuned to specific ultrasonic frequencies. These resonators act as mediators that selectively amplify desired ultrasonic frequencies while attenuating RF components, enabling clean separation of energy types. The resonator intermediaries resolve the contradiction by providing frequency-selective coupling between the combined signal source and the tissue target.
2Power
If high power is delivered to achieve effective cutting and coagulation, then surgical effectiveness is improved, but tissue damage and patient trauma increase
Solution Approach 1:
The patent applies different energy types (RF and ultrasonic) with different penetration depths and heating characteristics to achieve localized effects. RF energy provides deeper penetration for coagulation while ultrasonic energy offers superficial precision for cutting. This local quality differentiation allows effective tissue modification while minimizing collateral damage through selective energy application zones.
Solution Approach 2:
The patent employs pulsed or intermittent delivery of high-power RF and ultrasonic energies rather than continuous exposure. By controlling duty cycles and alternating between energy types, the system achieves effective surgical outcomes through periodic high-power bursts while allowing thermal diffusion and minimizing cumulative tissue trauma between pulses.
3Measurement precision
If separate generators are used for RF and ultrasonic energies, then signal purity and control precision are improved, but device complexity and procedural time increase
Solution Approach 1:
The patent combines RF and ultrasonic energy delivery into a single generator system with a unified control architecture. The generator produces a combined signal containing both frequency ranges, which is then separated using passive filtering components (bandpass filters and resonators). This merging approach maintains signal purity through frequency-based separation while reducing device complexity by eliminating the need for two independent generators and their associated 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
Enables precise control and customization of surgical procedures by allowing simultaneous or alternating application of ultrasonic and RF energies, improving tissue cutting, coagulation, and hemostasis while minimizing patient trauma.
Implementation Method 1
Vibrating at high frequencies (e.g., 55,500 times per second), the ultrasonic blade denatures protein in the tissue to form a sticky coagulum
Implementation Method 2
RF energy is a form of electrical energy that may be in the frequency range of 200 kilohertz (kHz) to 1 megahertz (MHz). In application, an electrosurgical device can transmit low frequency RF energy through tissue, which causes ionic agitation, or friction, in effect resistive heating, thereby increasing the temperature of the tissue
Implementation Method 3
high frequency filters configured to filter a combined ultrasonic and RF frequency signal into signals having only ultrasonic frequency content and separately, RF frequency content
Implementation Method 4
resonators configured to resonate at the ultrasonic frequency to block the ultrasonic frequency from the RF energy output
Data Source
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AI summary
Provided is an apparatus, system, and method for managing radio frequency (RF) and ultrasonic signals output by a generator that includes a surgical instrument comprising an RF energy output and an ultrasonic energy output and a circuit configured to receive a combined RF and ultrasonic signal from the generator, where the circuit may be configured to filter frequency content of the combined signal and is configured to provide a first filtered signal to the RF energy output and a second filtered signal to the ultrasonic energy output or the circuit may be configured to switch between outputs of the surgical instrument.