Patent Application
20190223937
The present disclosure generally relates to electrosurgical devices, and more particularly to electrosurgical devices powering ablation devices usable in surgical procedures.
Ablation devices have been used to remove tissue within patients in a variety of medical procedures. When in use, ablation devices are often operated throughout a range of power settings. Higher power settings are often used to remove tissue via vaporization and lower settings are used for desiccation. Some ablation devices include aspiration systems to remove fluid or particulates, or both, from a surgery site within a patient. Conventional aspiration systems remove fluid and particulates from a surgery site at the same aspiration rate regardless of the power setting of the active electrode. An aspiration rate large enough to properly remove material generated at a high power setting for an active electrode is too large of an aspiration rate for a low power setting for the active electrode. In particular, the aspiration rate corresponding with the high power setting interferes with a plasma field or ionized gas vapor layer at the active electrode generated at a low power setting such as by pulling the plasma field away from the active electrode, thus affecting the behavior of the plasma field.
An electrosurgical system including an electrosurgical unit with amplitude modulated output for ablation surgical devices, whereby the electrosurgical unit generates a signal in either a high mode or low mode, both of which are greater than zero, is disclosed. In at least one embodiment, the electrosurgical unit may be configured such that the power delivered to an electrode assembly of an ablation device in electrical communication with the electrosurgical unit is controlled by varying the duration or the intensity of power delivered during the high and low modes, or both. In another embodiment, the duration of the high mode may remain constant while the duration of the low mode may vary in order to vary the power output from the electrosurgical unit.
In at least one embodiment, the electrosurgical system may include an ablation device formed from an electrode assembly having an active electrode and a return electrode, wherein the active electrode is insulated from the return electrode. The electrosurgical system may be configured as a bipolar configuration, and in an alternative embodiment, may be a monopolar configuration. The electrosurgical system may include an electrosurgical unit configured to power the electrode assembly by generating a radio frequency output to drive the electrode assembly. The electrosurgical unit may be configured to generate an amplitude modulated waveform in which the waveform operates in a high mode or in a low mode, whereby both the high mode and the low mode are greater than zero amps. The electrosurgical unit may be configured to power the electrode assembly by generating the radio frequency output to drive the electrode assembly with the high mode continuously at a fixed time or the low mode at a variable time. The electrosurgical unit may be configured to power the electrode assembly by generating the radio frequency output to drive the electrode assembly with the high mode continuously at the fixed time or the low mode at the variable time at more than 0 Amps. In another embodiment, the electrosurgical unit may be configured to power the electrode assembly by generating the radio frequency output to drive the electrode assembly with the high mode continuously at the fixed time or the low mode at the variable time at more than 0.75 Amps. The electrosurgical unit may be configured to power the electrode assembly by generating a radio frequency output to drive the electrode assembly with the low mode at a variable time that is a function of impedance at a surgical site. In another embodiment, the electrosurgical unit may generate a radio frequency output with a variable time high mode and a fixed time low mode. In yet another embodiment, the electrosurgical unit may generate a radio frequency output with a variable time high mode and a variable time low mode.
The electrosurgical system may include a RF voltage sensor module and a RF current sensor module, which are configured to monitor, during each high mode, an RF signal generated by the electrosurgical unit to determine a voltage and a current, respectively, delivered to a surgical site via the electrode assembly. The electrosurgical system may also include one or more microcontrollers configured to communicate with the RF voltage current sensor module to determine impedance at a surgical site by dividing voltage by current at the electrosurgical unit. The electrosurgical system may also include one or more DC microcontrollers configured to use the impedance to determine how to deliver the RF output power to a surgical site by applying the impedance to a voltage, current and power curve. The impedance may be applied to the duration of the low mode to reduce the power defined by the VIP curve to a level that produces the appropriate RMS power. The DC microcontroller may be configured to store multiple voltage, current, power curves, whereby each voltage, current, power curve corresponds to a power setting on the ablation device. By determining the impedance, the DC microcontroller may work with the VIP curve and adjust the RMS power by appropriately adjusting the low mode time to adjust the output power.
The electrosurgical unit may be configured to power the electrode assembly by generating the radio frequency output to drive the electrode assembly with the high mode continuously at a fixed time of between about 15 and 40 milliseconds. In at least one embodiment, the electrosurgical unit may be configured to power the electrode assembly by generating the radio frequency output to drive the electrode assembly with the high mode continuously at a fixed time of about 25 milliseconds.
A method of controlling power deliver in an electrosurgical system may include receiving power in the electrosurgical system, whereby the electrosurgical system may include an ablation device formed from an electrode assembly having an active electrode and a return electrode, wherein the active electrode is insulated from the return electrode, and an electrosurgical unit configured to power the electrode assembly by generating a radio frequency output to drive the electrode assembly. The method may also include sending an amplitude modulated waveform from the electrosurgical unit to the electrode assembly, whereby the waveform operates in a high mode or in a low mode and both the high mode and the low mode are greater than zero amps, from the electrosurgical unit to the electrode assembly.
These and other embodiments are described in more detail below.
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.
As shown in
In at least one embodiment, the electrosurgical system 10 may be formed from an ablation device 16 formed from an electrode assembly 14 having an active electrode 18 and a return electrode 20. The active electrode 18 may be insulated from the return electrode 20. The electrosurgical system 10 may include an electrosurgical unit 12 configured to power the electrode assembly 14 by generating a radio frequency (RF) output to drive the electrode assembly 14. The electrosurgical unit 12 may be configured to genera an amplitude modulated waveform in which the waveform operates in a high mode or in a low mode, whereby both the high mode and the low mode are greater than zero amps. The electrosurgical unit 12 may be configured to power the electrode assembly 14 by generating the radio frequency output to drive the electrode assembly 14 with the high mode continuously at a fixed time or the low mode at a variable time. The electrosurgical unit may be configured to power the electrode assembly 14 by generating the radio frequency output to drive the electrode assembly 14 with the high mode continuously at the fixed time or the low mode at the variable time at more than zero Amps. In at least one embodiment, the electrosurgical unit may be configured to power the electrode assembly 14 by generating the radio frequency output to drive the electrode assembly 14 with the high mode continuously at the fixed time or the low mode at the variable time at more than 0.75 Amps. The electrosurgical unit 12 may be configured to power the electrode assembly 14 by generating a radio frequency output to drive the electrode assembly 14 with the low mode at a variable time that is a function of impedance at a surgical site.
The electrosurgical system 10 may also include a RF voltage sensor module 42 and a RF current sensor module 43 configured to monitor, during each high mode, an RF signal generated by the electrosurgical unit 12 to determine a voltage and a current, respectively, delivered to a surgical site via the electrode assembly 14. The electrosurgical system 10 may also one or more microcontrollers 24 configured to communicate with the RF voltage current sensor module 42 to determine impedance at a surgical site by dividing voltage by current at the electrosurgical unit 12. In at least one embodiment, the microcontroller 24 may be a DC microcontroller. The DC microcontroller 24 may be configured to use the impedance to determine how to deliver the RF output power to a surgical site by applying the impedance to a voltage, current and power curve. The DC microcontroller 24 may be is configured to store multiple voltage, current, power curves (VIPs) 26, whereby each voltage, current, power curve 26 corresponds to a power setting 28 on the ablation device 16. The electrosurgical unit 12 may be configured to power the electrode assembly 14 by generating the radio frequency output to drive the electrode assembly 14 with the high mode continuously at a fixed time of between about 15 and 40 milliseconds. In at least one embodiment, the electrosurgical unit 12 may be configured to power the electrode assembly 14 by generating the radio frequency output to drive the electrode assembly 14 with the high mode continuously at a fixed time of about 25 milliseconds.
In at least one embodiment, the electrosurgical unit 12 may be a generator that provides a RF output to drive a bipolar electrosurgical ablation device 16 through the application of an electric current conducted using two electrodes of the ablation device 16. The electrosurgical unit 12 may generate an RF output having a square wave at about 100 kHz or other appropriate output. The electrosurgical unit 12 may include one or more voltage, current, power curves 26, as shown in
In at least one embodiment of the electrosurgical system 10, as shown in
A drive circuit 36 drives one or more transistors, such as, but not limited to upper and lower power transistors, in the full-bridge DC amplifier 34, whose output may be applied to a DC power supply transformer 40. The DC power supply transformer 40 may provide isolation between the AC main circuits and the high-voltage intermediate circuits. When the RF amplifier 38 begins to deliver RF energy to a surgical site, the electrosurgical unit 12, such as, but not limited, to the PFC circuit 28 sense the DC voltage and current and feed back into the DC microcontroller 24. The DC microcontroller 24 may control the output power using a controller algorithm and RMS voltage and current produced by RF voltage/current and arc detection circuitry 42. In at least one embodiment, the DC microcontroller 24 may control the output power via software contained in the DC microcontroller 24. In at least one embodiment, the microcontroller 24 of the electrosurgical unit 12 uses a control algorithm to properly control the RF output characteristics of the electrosurgical unit 12 to provide a stable RF output to a surgical site on or within a patient.
In at least one embodiment, the ablation device 16 may include controls 44 for controlling operating of the electrode assembly 14. In particular, the controls 44 may include controls for ablation mode, coagulation mode and power levels. In at least one embodiment, the controls 44 may be physical buttons for ablation mode, coagulation mode and power levels. In other embodiments, the controls 44 may be formed from other appropriate devices. The power level control may include power level settings from 1 to 9. The electrosurgical system 10 may also include one or more footswitches to control the on/off settings of the electrosurgical unit 12. As such, a surgeon using the ablation device 16 may be able to prioritize operation and control between the ablation device 16 and footswitch.
In at least one embodiment, the electrosurgical system 10 may be configured to operate in two different modes of operation: ablation and coagulation. The ablation mode may have two different operating characteristics: continuous waveform and amplitude modulated waveform. The amplitude modulated waveform may include a High mode continuously for a fixed amount of time and a Low mode as a variable time that is a function of the impedance at the surgical site. During each High mode, the RF voltage/current sense circuit 42 may monitor the actual current and voltage being delivered to the surgical site. The DC microcontroller 24 may obtain the impedance at the surgical site by dividing the voltage by the current. The microcontroller 24 applies the measured impedance to a voltage, current, power (VIP) curve to define how the RF output power is to be delivered to the surgical site. Each power setting, such as power settings 1-9, is matched with a different VIP power curve. Each VIP power curve is defined to match the output characteristics of the ablation device 16. An exemplary VIP power curve is shown in
As shown in
An impedance switching point is defined for each power setting. The impedance switching point is a point at which the output operates in the continuous waveform or the amplitude modulated waveform for the ablation mode as discussed above. As shown in the exemplary VIP curve in
The DC microcontroller 24 may use energy sensed by the voltage sense circuit 28 and current sense circuit 29 (i.e., the measured impedance) to define where the electrosurgical unit 12 should be operating in relation to the VIP power curve, such as in one of the regions with a voltage limit, current limit, or power limit. The DC microcontroller 24 may continuously monitor where the electrosurgical unit 12 should be operating in relation to the VIP power curve and may maintain a condition throughout a 25 ms timeframe. At the end of a 25 ms duration, the DC microcontroller 24 may determine the output impedance and may determine whether the output characteristic generated from the electrosurgical unit 12 as an RF signal should be transmitted in a continuous waveform or an amplitude modulated waveform. If the electrosurgical unit 12 is operating in the amplitude modulated waveform, the DC microcontroller 24 may determine an appropriate duration to operate in the Low mode that, when combined with the duration of the High mode, will generate a variable amplitude modulation (HIGH amplitude modulated duration/(HIGH amplitude modulated duration+LOW amplitude modulated duration) ratio, where the High duration time is always a fixed time, such as, but not limited to 25 ms). By combining the amplitude modulation with the VIP power curve, such as with the DC microcontroller 24, a desired RMS output power can be defined. In particular, for a given power setting, as shown in the exemplary VIP curve in
As shown in
The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include sending the amplitude modulated waveform, whereby the amplitude modulated waveform is a radio frequency output configured to drive the electrode assembly with the high mode continuously at a fixed time or the low mode at a variable time. The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include sending the amplitude modulated waveform, whereby the amplitude modulated waveform is formed from both the high mode operating continuously at the fixed time or the low mode operating at the variable time at more than 0.75 Amps. The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include sending the amplitude modulated waveform, whereby the amplitude modulated waveform is a radio frequency output configured to drive the electrode assembly 14 with the low mode at a variable time that is a function of impedance at a surgical site.
The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include determining a current and a voltage delivered to a surgical site via the electrode assembly with use of a RF voltage current sensor module 42 configured to monitor, during each high mode, an RF signal generated by the electrosurgical unit 12. The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include determining impedance at a surgical site via at least one microcontroller 24 configured to communicate with the RF voltage current sensor module 42 to determine impedance at a surgical site by dividing voltage by current at the electrosurgical unit 12.
The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include determining impedance at a surgical site via the DC microcontroller 24 using the impedance to determine how to deliver the RF output power to a surgical site by applying the impedance to a voltage, current and power curve. The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include determining impedance at a surgical site via the DC microcontroller 24 accessing multiple voltage, current, power curves, whereby each voltage, current, power curve corresponds to a power setting on the ablation device 16. The step at 54 of sending the amplitude modulated waveform from the electrosurgical unit 12 to the electrode assembly 14 may include generating the radio frequency output to drive the electrode assembly 14 with the high mode continuously at a fixed time of between about 15 and 40 milliseconds.
The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.
