Electrosurgical device, impedance measuring device of the electrosurgical device, energy control method for tissue coagulation, and impedance measuring method
It relates to an electrosurgical device, an impedance measuring device of the electrosurgical device, an energy control method for tissue coagulation, and an impedance measuring method, the electrosurgical device is comprised of an instrument for surgery on a target tissue, a processor configured to control energy supply to the instrument and an impedance measurement unit configured to measure an impedance of the target tissue, wherein the processor is further configured to if the impedance measured by the impedance measurement unit exceeds a first reference value, stop the energy supply to the instrument during a stop period, resume the energy supply to the instrument after the stop period has elapsed, and determine a coagulation state based on the impedance of the target tissue measured after the resumption of the energy supply by the impedance measurement unit.
1 . An electrosurgical device, the device comprising:
an instrument for surgery on a target tissue;
a processor configured to control energy supply to the instrument;
an impedance measurement circuit configured to measure an impedance of the target tissue;
a voltage-current measuring circuit; and
wherein the processor is further configured to stop the energy supply to the instrument during a stop period when the impedance measured by the impedance measurement circuit exceeds a first reference value, resume the energy supply to the instrument after the stop period has elapsed, and determine a coagulation state based on the impedance of the target tissue measured after the resumption of the energy supply by the impedance measurement circuit,
wherein the voltage-current measuring circuit comprises:
a capacitor;
an isolation transformer connected to the capacitor and configured to output a first voltage signal corresponding to a voltage;
a PCB Rogowski coil installed adjacent to a conducting wire to which the capacitor is connected; and
an active integrator connected to the PCB Rogowski coil and configured to correct a phase of the active integrator to output a second voltage signal corresponding to a current, and
wherein the impedance measurement circuit comprises:
a first active low-pass filter configured to remove a harmonic component of the first voltage signal, the first active low-pass filter having a cutoff frequency lower than a second harmonic of a frequency to be measured such that the harmonic component is removed;
a first multiplication processor configured to perform a multiplication process on an output of the first active low-pass filter;
a first passive low-pass filter configured to obtain a direct current component corresponding to a voltage from a result of the first multiplication processor;
a second active low-pass filter configured to remove a harmonic component of the second voltage signal, the second active low-pass filter having a cutoff frequency lower than a second harmonic of a frequency to be measured such that the harmonic component is removed;
a second multiplication processor configured to perform a multiplication process on an output of the second active low-pass filter;
a second passive low-pass filter configured to obtain a direct current component corresponding to a current from a result of the second multiplication processor;
a third multiplication processor configured to perform a multiplication process on an output of the first active low-pass filter and the second active low-pass filter;
a third passive low-pass filter configured to obtain a direct current component corresponding to a phase from a result of the third multiplication processor; and
a result acquisition processor configured to determine a voltage and a current, based on the direct current component corresponding to the voltage and the direct current component corresponding to the current, to determine a phase by dividing the direct current component corresponding to the phase by a magnitude of the voltage and a magnitude of the current and performing an inverse trigonometric function operation on a result of the division, and to determine an impedance based on the voltage, the current, and the phase.
2 . The electrosurgical device of claim 1 ,
wherein the processor is configured to control the energy supply to the instrument using at least one lookup table.
3 . The electrosurgical device of claim 1 ,
wherein the processor is further configured to determine a moisture amount of surrounding tissues of the target tissue by using the impedance of the target tissue measured by the impedance measurement circuit after the energy supply is resumed, and determine the coagulation state based on the moisture amount.
4 . The electrosurgical device of claim 1 ,
wherein the processor is configured to block the energy supply to the instrument when a total surgical time exceeds a reference time.
5 . An electrosurgical method, the method comprising:
supplying energy to an instrument for surgery of a target tissue;
measuring an impedance of the target tissue;
stopping the energy supply to the instrument during a stopping period when the impedance measured by the impedance measuring circuit exceeds a first reference value;
resuming the energy supply to the instrument after the stopping period has elapsed; and
determining a coagulation state based on the impedance of the target tissue measured after resuming the energy supply,
wherein the measuring an impedance of the target tissue comprises:
measuring a voltage and a current; and
obtaining an impedance based on a first voltage signal and a second voltage signal,
wherein the voltage and the current are measured by using a voltage-current measuring circuit,
wherein the voltage-current measuring circuit comprises:
a capacitor;
an isolation transformer connected to the capacitor and outputting the first voltage signal corresponding to the voltage;
a PCB Rogowski coil installed adjacent to a conducting wire to which the capacitor is connected; and
an active integrator connected to the PCB Rogowski coil and correcting a phase to output the second voltage signal corresponding to the current, and
wherein the obtaining an impedance based on the first voltage signal and the second voltage signal comprises: p 2 removing a harmonic component from each of the first voltage signal and the second voltage signal, by allowing each of the voltage signals to have a cutoff frequency lower than a second harmonic of a frequency to be measured;
performing multiplication on each of the first voltage signal from which the harmonic component is removed and the second voltage signal from which the harmonic component is removed;
obtaining a direct current component corresponding to a voltage and a direct current component corresponding to a current from each multiplication result;
performing multiplication by using both the first voltage signal from which the harmonic component is removed and the second voltage signal from which the harmonic component is removed;
obtaining a direct current component corresponding to a phase from a multiplication result using both the first voltage signal from which the harmonic component is removed and the second voltage signal from which the harmonic component is removed;
determining a voltage and a current, based on the direct current component corresponding to the voltage and the direct current component corresponding to the current;
determining a phase by dividing the direct current component corresponding to the phase by a magnitude of the voltage and a magnitude of the current and performing an inverse trigonometric function operation on a result of the division; and
determining the impedance based on the voltage, the current, and the phase.
6 . The electrosurgical method of claim 5 ,
wherein the supplying energy to an instrument for surgery of a target tissue comprises:
supplying energy to the instrument for the surgery of the target tissue using at least one lookup table.
7 . The electrosurgical method of claim 5 ,
wherein the determining the coagulation state based on the impedance of the target tissue measured after resuming the energy supply comprises:
determining a moisture amount of surrounding tissue of the target tissue by using the impedance of the target tissue measured after the energy supply resumption; and
determining the coagulation state based on the moisture amount around the target tissue.
8 . The electrosurgical method of claim 5 , further comprising:
blocking the energy supply to the instrument when a total surgical time exceeds a reference time.