DE102015119694A1 - Electrosurgical system for the resection of body tissue - Google Patents

Abstract

The invention relates to an electrosurgical system (10) for the resection of body tissue of a body with an electrosurgical instrument (12), a first electrode (20), a second electrode (22), a high voltage supply unit (14, 16) and a control unit (18). The electrosurgical instrument (12) has the first electrode (20). The first electrode (20) is adapted for electrosurgical cutting and coagulation of body tissue. The high voltage supply unit (14, 16) is electrically connected to the first electrode (20) and the second electrode (22) and formed to supply these electrodes (20, 22) with voltage pulses. The controller (18) is connected to the high voltage supply unit (14, 16) and configured to control delivery of energy via the electrosurgical instrument (12). The electrosurgery system (10) is designed to generate short-lived gas bubbles (34a, 34b, 34c, 34d) by means of the electrosurgical instrument (12) in a liquid (24) that is in contact with the electrosurgical instrument (12) during operation.

Description

The invention relates to an electrosurgical system for the resection of body tissue of a body and to a method for operating such an electrosurgical system.

Electrosurgical systems for the resection of body tissue are known in principle. Electrosurgical systems typically include two or more electrodes for cutting, vaporizing, vaporizing, and / or coagulating tissue. For example, a first electrode may be disposed on an electrosurgical instrument, and a second electrode may be disposed as a neutral electrode with a larger area than the first electrode. Alternatively, two or more electrodes may also be arranged on the electrosurgical instrument. The electrodes are typically connected to a high frequency, high voltage power supply that supplies the electrodes with a high frequency AC voltage so that they can dissipate energy in the form of heat, as an arc between the electrodes, or as a plasma. For example, the arc or plasma can be used to cut tissue.

Electrosurgical systems are used, among other things, to treat so-called Benign Prostatic Hyperplasia (BPH). Benign Prostatic Hyperplasia (BPH) is a benign tissue proliferation that results in enlargement of the prostate gland. As a result, the urinary tract can be narrowed or blocked, so that a bladder emptying difficult or prevented.

One or more electrodes of the electrosurgical system are brought near the treatment site for the treatment of benign prostatic hyperplasia (BPH). The electrodes of the electrosurgical system can then be used, for example, for piecewise removal of the tissue proliferation. Here, i. in the piecewise resection, a high-frequency AC voltage is applied to the electrodes in order to cut and ablate the tissue in pieces. Alternatively, the tissue can also be vaporized by means of the electrodes. Alternative methods, such as the so-called HoLEP (holmium laser enucleation of the prostate) method allow the tissue to be vaporized by means of a pulsed high-energy laser. Pulsed high energy lasers and the electrodes may also be used for so-called enucleation of the hyperplastic tissue, i. Removing a delimited area along an anatomical layer, can be used.

The treatment of the tissue is typically made possible by a temperature increase of the tissue to over 100 ° C during cutting or vaporization and between 60 ° C and 70 ° C during coagulation. When coagulated, the proteins denature in the tissue wall. In a conductive medium, such as in an isotonic saline solution, further, a cold plasma can be generated, which can cut and / or coagulate the tissue even at a lower temperature.

In the HoLEP process, a laser beam is transported through an optical fiber. In front of the optical fiber, the laser beam is focused and defocused behind the optical fiber with the same pulse energy, pulse time and pulse frequency. This creates an inhomogeneous temperature profile in the HoLEP process that allows for simultaneous vaporization (at the focal point of the light) and coagulation of the tissue (behind the focal plane at lower energy density). The energy of the laser beam is essentially absorbed by water. This can either be water within a body, in particular within body cells, or an added water-containing rinsing liquid. The focus of the laser beam is due to the increased energy density for vaporization and in the surrounding areas for coagulation. The HoLEP method uses a holmium laser with a pulsed laser beam at a frequency of about 50 Hz. In addition to increasing the temperature in the liquid, short-lived water vapor bubbles are generated at the focal point of the laser light, producing pressure surges when they decay. The waves generated by the pressure surges are comparable to cavitation waves, which can be generated by fast movements of objects in the liquid. This has three effects on the tissue to be treated when the HoLEP method is used to resect the tissue. First, the tissue is vaporized due to the increased energy density or temperature. Second, the tissue is coagulated. Third, there is a mechanical breakdown of the tissue by the pressure surges, which are due to the implosions or the disintegration of the gas bubbles.

The aim of the invention is to provide an improved electrosurgical system.

This object is achieved by an electrosurgical system for the resection of body tissue of a body with an electrosurgical instrument, at least one first electrode, at least one second electrode, a high voltage supply unit and a control unit. The electrosurgical instrument has the first electrode. The first electrode is adapted for electrosurgical cutting and coagulation of body tissue. The high voltage power supply unit is electrically connected to the first electrode and the second electrode and forms these electrodes to supply with voltage pulses. The controller is connected to the high voltage supply unit and configured to control a delivery of energy via the electrosurgical instrument. The electrosurgical system is designed to generate short-lived gas bubbles by means of the electrosurgical instrument in a liquid which is in contact with the electrosurgical instrument during operation.

The electrosurgical system may include two or more electrodes, for example, three, four, or more electrodes. The additional electrodes may be disposed near the first or second electrode to independently regulate the streams for vaporising, coagulating, or generating vapor bubbles. If the second electrode is designed as a neutral electrode, the additional electrodes can be arranged, for example, remotely to the electrosurgical instrument. In particular, during operation, the neutral electrode may be disposed on a surface of the body whose body tissue is treated by means of the electrosurgical system. The additional electrodes can also be arranged on the electrosurgical instrument. The electrodes comprise an electrically conductive material, preferably a metal such as platinum, gold or the like, a metallic alloy such as steel or the like, another electrically conductive material or other electrically conductive material composition. The electrically conductive material, in particular the metal, is preferably biocompatible.

The high voltage power supply unit may be, for example, a voltage generator, an AC voltage generator, a DC voltage generator, a high frequency high voltage power supply unit, or the like. Preferably, the high voltage supply unit is a voltage generator which can generate both AC voltage and DC voltage. The high voltage power supply may also include an AC generator and a DC generator. Preferably, the high voltage supply unit controls the different electrodes.

The controller may be configured to be manually activated by a user, manually operated by a user, automatically activated and / or programmed under predetermined conditions. The electrosurgical system can have, for example, a user interface with which the control unit can be manually activated and / or operated by the user. As a result, the electrosurgical system can be manually activated and / or operated by the user. A predetermined condition may be, for example, the recognition of a particular tissue or a particular type of tissue. For this purpose, the electrosurgical system can have a sensor system which is designed to detect different types of tissue or tissue and their properties. For example, the controller may be programmed to operate the electrosurgical system for a predetermined amount of time upon activation.

With conventional electrosurgical systems with electrodes, a similar temperature distribution can be achieved as for the HoLEP method described above, by controlling the current density between two electrodes. This is possible, for example, via the shape of the electrodes. A higher current density generates a higher temperature than a lower current density in a medium with a constant resistance. However, the other benefits of the HoLEP method for the enucleation of hyperplastic tissue using the electrodes are not achieved. The invention has recognized that the treatment of tissue can be improved by forming an electrosurgical system with electrodes for generating short-lived gas bubbles in a liquid that is in contact with the electrosurgical instrument during operation. In this way, additional pressure surges are introduced into the liquid, which act on the tissue and this damage and weaken. In particular, damage, weakening or disassembly occurs along a separation layer between two different types of tissue. One aspect of the invention is therefore that three effects on the tissue to be treated, when an electrosurgical instrument according to the invention for resection of body tissue is used. First, the body tissue is vaporized or cut due to the elevated temperature around the first electrode. Second, the body tissue is coagulated. Third, mechanical breakdown of body tissue occurs through pressure surges due to implosions of the short-lived gas bubbles generated by the electrosurgical system. In addition, a mechanical dissection of the body tissue is possible by a shaft of the electrosurgical instrument is pressed against the body tissue.

The voltage pulses are preferably short DC voltage pulses and / or AC voltage pulses. AC pulses are preferably used to cut and coagulate the tissue. Short DC pulses are preferably used to generate short-lived gas bubbles. The DC pulses are short in relation to the AC pulses used to cut and coagulate the tissue. The pulse duration of the DC voltage pulses is preferably less than 1 ms and the pulse duration of the AC voltage pulses more than 1 ms. The AC pulses are with created a first frequency. The first frequency of the AC pulses may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz. An AC voltage in this frequency range can reduce neuromuscular stimulation when used in a body. Preferably, the first frequency of the alternating voltage pulses in an embodiment with two electrodes between 100 kHz and 2 MHz, and more preferably between 200 kHz and 400 kHz.

In a preferred embodiment, the control device is designed to control the high-voltage supply unit such that it supplies the electrosurgical instrument with DC voltage pulses and / or AC voltage pulses. A peak amplitude or voltage amplitude of the voltage applied to the electrosurgical system and / or an energy output to the electrosurgical system are preferably set such that the electrosurgical instrument generates short-lived gas bubbles in the liquid that is in contact with the electrosurgical instrument during operation.

In a further preferred refinement, the control unit is designed to control the high-voltage supply unit in such a way that the output voltage varies in time in two or more sections. For this purpose, the electrosurgical instrument can be supplied with two or more different voltage pulses, wherein in one or more time periods no voltage pulse or a voltage pulse with a voltage value of 0 V can be output. Particularly preferably, the control device is designed to repeat a sequence of voltage pulses with different output lengths to produce a continuous output of a voltage sequence. Furthermore, the control unit is particularly preferably designed to repeat the sequence of voltage pulses with a frequency between 1 Hz and 10 kHz. Preferably, the peak voltage of at least one of the voltage pulses applied to the electrosurgical system is adjusted such that the electrosurgical instrument generates short-lived gas bubbles in the liquid in contact with the electrosurgical instrument. The values of frequency, waveform, peak voltage, and duration may vary for the voltage pulses in the different time periods of the output voltage. In particular, a DC voltage can also be output in one or more time periods. The control unit can thus be designed to control the high-voltage supply unit in such a way that DC voltage pulses are generated alternating with AC voltage pulses. The pulse duration of the DC voltage pulses is preferably less than 1 ms and the pulse duration of the AC voltage pulses greater than 1 ms. The control unit may also be designed to control the high-voltage supply unit in such a way that it alternately generates alternating-voltage pulses with different amplitudes and frequencies of different duration. In this case, two, three or more different AC pulses may alternate. Alternatively or additionally, an energy delivery to the electrosurgical system is preferably set such that the electrosurgical instrument generates a short-lived gas bubbles in the liquid which is in contact with the electrosurgical instrument during operation by means of a DC voltage. Thus, either the peak amplitude, the energy output or both can be set so that short-lived gas bubbles arise. The key is that short-lived gas bubbles are generated, i. Gas bubbles are generated, which disintegrate again after a short time. On the one hand, this can be achieved by a particularly high peak amplitude for a short period, i. a high power is delivered for a short time. On the other hand, this can also be achieved by delivering less power over a somewhat longer period of time sufficient to produce short-lived gas bubbles, i. Although a slightly lower power is delivered, but this allows it to generate short-lived gas bubbles, given the slightly longer delivery period. This embodiment of the electrosurgical system makes it possible to improve the treatment of tissue, since in this embodiment pressure surges or pressure waves are introduced into the fluid with the aid of the voltage applied to the electrodes with the second function. Thus, it is possible with the design to achieve the three effects for the treatment of the tissue.

In a preferred embodiment, the control unit is designed to control the high voltage supply unit such that it emits a series of voltage pulses, so that the energy delivery to the electrosurgical system is set such that periodically plasma discharges emanate from the first electrode and in this way short-lived gas bubbles in the in operation arise with the first electrode in contact liquid and surrounding tissue is vaporized or coagulated.

In a further refinement, the high-voltage supply unit is designed to continuously supply the electrodes with alternating-current pulses so that, as a result, they are continuously supplied with an alternating voltage having a first frequency. This alternating voltage is preferably used for cutting and coagulating. Preferably, the applied AC voltage can be modulated by a second function as a modulation function with a second frequency. The modulation function is in this case designed to modulate the AC voltage with the first frequency to a function with a second frequency. Preferably, the second frequency is less than 200 kHz. Particularly preferably, the second frequency is between 1 Hz and 10 kHz. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The modulation function can be, for example, a pulse wave oscillation with a predetermined pulse length, pulse amplitude and pulse frequency. This results in a more complex voltage output which is repeated with the modulation frequency. Preferably, a peak amplitude of the modulated AC voltage is set such that periodically plasma discharges emanate from the first electrode and in this way short-lived gas bubbles are formed in the liquid in contact with the first electrode during operation. Additionally or alternatively, an energy delivery to the electrosurgical system is preferably set in such a way that plasma discharges periodically emanate from the first electrode and in this way short-lived gas bubbles are formed in the liquid which is in contact with the first electrode during operation. Even with this embodiment, it is possible to improve the treatment of the tissue.

In a preferred embodiment, the electrosurgical system has at least three electrodes. The electrosurgical system may also include four or more electrodes. Preferably, the controller is adapted to drive the high voltage supply unit such that the high voltage supply unit supplies two of the three or four electrodes with voltage pulses having a predetermined DC voltage or first AC voltage having a predetermined frequency, pulse duration and peak voltage for generating the gas bubbles and the high voltage supply unit is two of the three or four Electrodes are continuously supplied with voltage pulses with a second AC voltage of predetermined frequency, pulse duration and peak voltage for cutting and coagulation, ie the high voltage supply unit supplies the electrodes with a continuous AC voltage having a frequency which is preferably different from the frequency of the first AC voltage. In this case, in an electrosurgical system with three electrodes, one of the three electrodes is supplied by the high-voltage supply unit both with the voltage pulses and with the continuous second AC voltage. In the case of an electrosurgical system with four electrodes, preferably two electrodes each are supplied with the voltage pulses of first direct voltage or first alternating voltage and two electrodes of the continuous second alternating voltage. In electrosurgery systems having more than four electrodes, the controller is preferably configured to drive the high voltage supply unit to supply two non-voltage pulsed electrodes with the continuous second AC voltage to cut and coagulate with these tissues. Gas bubbles may be selectively generated during cutting and coagulation, either periodically by means of voltage pulses delivered to the other electrodes, for example by means of a sensor system that detects and in turn generates a voltage pulse or manually generates certain types of tissue For example, a user may manually activate the voltage pulses using a user interface, such as a switch.

In a further preferred embodiment, the cross section of at least one of the electrodes has at least four corners. The corners can also be rounded. Particularly preferably, the cross section of the at least one electrode is rectangular, wherein the corners may also be rounded. For example, a rectangular first electrode can be arranged in the electrosurgical instrument and a large-area rectangular or differently shaped second electrode can be arranged as a neutral electrode with distance to the electrosurgical instrument. In particular, during operation, the neutral electrode may be disposed on a surface of the body whose body tissue is treated by means of the electrosurgical system. Preferably, the first and second electrodes are rectangular and arranged in the electrosurgical instrument. In this case, an electrically non-conductive insulation is arranged between them. The insulation may be, for example, an electrically non-conductive insulating layer of an electrically non-conductive or electrically insulating plastic, such as polyamide or the like.

In one embodiment, the electrosurgical system has a supply line connected to the electrosurgical instrument. The supply line is preferably designed to supply the liquid, which is in contact with the first electrode during operation, with a fluid containing purisols and / or saline. The fluid may also include, for example, medicaments, a cooling fluid, marking fluid, or other fluids used to treat body tissue. For example, the delivery conduit may be disposed with a distal end at a treatment site within a body so as to deliver the fluid from a location external to the body to the treatment site. This embodiment makes it possible to improve the treatment by, for example, cooling the electrodes, supplying the body tissue with medication, or the conductivity of the first electrode in contact Liquid can be changed. It is also possible to change other properties of the liquid, for example its viscosity.

In a preferred embodiment, the electrosurgical system is designed to deliver pulses to the first electrode in order to generate pulsed plasma discharges. The pulses preferably have a power between 100 W and 10 kW, more preferably between 1000 W and 5000 W. The pulse duration of the pulses is preferably less than 1 ms, more preferably between 100 ns and 100 μs. The repetition rate F of the pulses is preferably between 1 Hz and 10 kHz, more preferably between 25 Hz and 250 Hz. One aspect is that with the selection of the specific parameters, a similar heat generation as with the holmium laser of the HoLEP method, i. Up to 10 J per pulse can be generated.

In one embodiment of the electrosurgical system, two electrodes may be arranged relative to an optic of an endoscope so that the electrodes of the electrosurgical system are not arranged in the field of view of the optics of the endoscope, so that any flashes of plasma discharges generated by the electrodes will not disturb the endoscopic image ,

In a further preferred embodiment, the electrosurgical instrument is designed to direct the pressure waves resulting from the disintegration of the gas bubbles in a direction away from the electrosurgical instrument. For this purpose, the electrosurgical instrument preferably has a housing with a flat or curved, hard surface into which the electrodes are inserted. The surface may also be designed in such a way that it focuses the pressure waves produced by the disintegration of the gas bubbles to a point. Most preferably, the distal ends of the electrodes terminate with the surface of the housing. The surface may, for example, be parabolic-cylindrical, paraboloid-shaped, hyperbolic-paraboloidal, hemispherical, or have a similar shape that allows steering or focusing of the pressure waves. A preferred form of surface is parabolic-cylindrical.

In a further preferred embodiment, the electrosurgical instrument has an actuator. The actuator is disposed in the fluid during operation and is configured to move back and forth at a speed relative to the rest of the electrosurgical instrument. Preferably, the relative movement between the actuator and the remaining electrosurgical instrument is so fast that short-lived gas bubbles arise as a result of cavitation in the liquid in contact with the actuator. For this purpose, the actuator is preferably supplied with energy by the high-voltage supply unit. The control unit is preferably designed to adjust the energy output of the high-voltage supply unit so that the relative movement between the actuator and the remaining electrosurgical instrument is so fast that gas bubbles are generated as a result of cavitation. This embodiment of the electrosurgical system makes it possible to improve the treatment of tissue, as in this embodiment, pressure surges are introduced into the liquid by means of the rapid back and forth movement of the actuator relative to the rest of the electrosurgical instrument. The pressure surges are caused by the implosion or the decay of the gas bubbles generated during the rapid relative movement. Thus, it is possible with the design to achieve the three effects for the treatment of the tissue. Furthermore, the generation of gas bubbles can also be combined by means of the rapid relative movement of the actuator with the modulation of the amplitude of the alternating voltage applied to the electrodes. As a result, the treatment of the tissue can be further improved. The actuator can be operated independently of the electrodes. The gas bubbles generated by the actuator can therefore also be dispensed, for example, in pulses, while the electrodes are continuously cut and coagulated.

• – Anordnen des Elektrochirurgieinstruments in einer Flüssigkeit,
• – Anlegen wenigstens eines Gleichspannungs- oder Wechselspannungspulses an eine erste Elektrode des Elektrochirurgieinstruments und eine zweite Elektrode des Elektrochirurgiesystems, wobei eine Spitzenamplitude der an das Elektrochirurgiesystem angelegten Spannung und/oder eine Energieabgabe an das Elektrochirurgiesystem derart eingestellt sind, dass das Elektrochirurgieinstruments kurzlebige Gasblasen in einer im Betrieb mit dem Elektrochirurgieinstrument in Kontakt stehenden Flüssigkeit erzeugt. Bevorzugt hat der wenigstens eine Wechselspannungspuls eine erste Frequenz. Die erste Frequenz des Wechselspannungspulses kann zwischen 100 kHz und 2 MHz, beispielsweise zwischen 200 kHz und 400 kHz liegen. Bevorzugt werden die Spannungspulse mit einer zweiten Frequenz wiederholt. Die zweite Frequenz ist bevorzugt geringer als die erste Frequenz und beträgt besonders bevorzugt nur einen Bruchteil der ersten Frequenz. Die Wiederholungsrate der Spannungspulse liegt bevorzugt zwischen 1 Hz und 10 kHz, besonders bevorzugt zwischen 25 Hz und 250 Hz.
• – Anlegen einer Wechselspannung an die erste oder eine weitere Elektrode des Elektrochirurgieinstruments und eine zweite Elektrode des Elektrochirurgiesystems zum elektrochirurgischen Schneiden und Koagulieren. Bevorzugt hat die Wechselspannung eine erste Frequenz. Die erste Frequenz der Wechselspannung kann beispielsweise zwischen 100 kHz und 2 MHz und bevorzugt zwischen 200 kHz und 400 kHz liegen.

The invention further relates to a method for operating an electrosurgical system with an electrosurgical instrument. The method comprises the method steps:

• Arranging the electrosurgical instrument in a liquid,
• Applying at least one DC or AC voltage pulse to a first electrode of the electrosurgical instrument and a second electrode of the electrosurgical system, wherein a peak amplitude of the voltage applied to the electrosurgical system and / or energy delivery to the electrosurgical system is set such that the electrosurgical instrument delivers short lived gas bubbles in an electrosurgical system Operation produced with the electrosurgical instrument in contact fluid. Preferably, the at least one alternating voltage pulse has a first frequency. The first frequency of the alternating voltage pulse may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz. Preferably, the voltage pulses are repeated at a second frequency. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The repetition rate of the voltage pulses is preferably between 1 Hz and 10 kHz, more preferably between 25 Hz and 250 Hz.
• - Applying an AC voltage to the first or another electrode of the electrosurgical instrument and a second electrode of the electrosurgical system for electrosurgical cutting and coagulation. Preferably, the AC voltage has a first frequency. The first frequency of the alternating voltage may for example be between 100 kHz and 2 MHz and preferably between 200 kHz and 400 kHz.

In a preferred embodiment, the output voltage applied to the first and second electrodes is temporally varied in two or more sections, i. a sequence of voltage pulses is applied. Thus, the electrosurgical instrument is supplied with two or more different voltages, wherein in one or more time periods, no voltage can be applied or a series of voltage pulses with a voltage value of 0 V. Preferably, the sequence of voltage pulses with different output lengths is repeated by a continuous Generate output of a voltage sequence. Particularly preferably, the sequence of voltage pulses is repeated at a frequency between 1 Hz and 10 kHz. Alternatively or additionally, an energy delivery to the electrosurgical system can be set such that plasma discharges emanate periodically from the first electrode and in this way short-lived gas bubbles are formed in the liquid in contact with the first electrode during operation.

In a further embodiment, a continuous series of alternating voltage pulses is applied to the first and second electrodes, so that, as a result, a continuous alternating voltage having a first frequency is applied. The continuous alternating voltage is preferably modulated by a second function as a modulation function with a second frequency. The modulation function is designed in this case to modulate the alternating voltage with the first frequency by a function with the second frequency. Particularly preferably, the continuous alternating voltage is modulated in such a way that a peak amplitude of the voltage applied to the electrosurgical system and / or an energy delivery to the electrosurgical system are set such that the electrosurgical instrument generates short-lived gas bubbles in a liquid which is in contact with the electrosurgical instrument during operation. Preferably, the second frequency is less than 200 kHz. Particularly preferably, the second frequency is between 1 Hz and 10 kHz. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The modulation function can be, for example, a pulse wave oscillation with a predetermined pulse length, pulse amplitude and pulse frequency. This results in a more complex voltage output which is repeated with the modulation frequency. Preferably, a peak amplitude of the modulated AC voltage is set such that periodically plasma discharges emanate from the first electrode and in this way short-lived gas bubbles are formed in the liquid in contact with the first electrode during operation.

• – Anordnen des Elektrochirurgieinstruments in einer Flüssigkeit,
• – Anlegen einer Wechselspannung mit einer ersten Frequenz an die erste Elektrode des Elektrochirurgieinstruments und die zweite Elektrode des Elektrochirurgiesystems zum elektrochirurgischen Schneiden und Koagulieren,
• – Betreiben des Aktuators, so dass sich dieser mit einer Geschwindigkeit relativ zum restlichen Elektrochirurgieinstrument vor und zurück bewegt, dass kurzlebige Gasblasen in Folge von Kavitation in der mit dem Aktuator in Kontakt stehenden Flüssigkeit entstehen.

Furthermore, the invention relates to a method for operating an electrosurgical system according to the invention with an electrosurgical instrument having an actuator. The method comprises the method steps:

• Arranging the electrosurgical instrument in a liquid,
• Applying an alternating voltage with a first frequency to the first electrode of the electrosurgical instrument and the second electrode of the electrosurgical system for electrosurgical cutting and coagulation,
• Operating the actuator so that it moves back and forth at a speed relative to the rest of the electrosurgical instrument, resulting in short-lived gas bubbles due to cavitation in the fluid in contact with the actuator.

• – Anordnen des Elektrochirurgieinstruments in einer Flüssigkeit.
• – Anlegen wenigstens eines Gleichspannungspulses und/oder Wechselspannungspulses an eine erste und zweite Elektrode des Elektrochirurgieinstruments, wobei eine Spitzenamplitude der an das Elektrochirurgiesystem angelegten Spannung und/oder eine Energieabgabe an das Elektrochirurgiesystem derart eingestellt sind, dass das Elektrochirurgieinstruments kurzlebige Gasblasen in einer im Betrieb mit dem Elektrochirurgieinstrument in Kontakt stehenden Flüssigkeit erzeugt. Bevorzugt hat der wenigstens eine Wechselspannungspuls eine erste Frequenz. Die erste Frequenz des Wechselspannungspulses kann zwischen 100 kHz und 2 MHz, beispielsweise zwischen 200 kHz und 400 kHz liegen. Bevorzugt werden die Spannungspulse mit einer zweiten Frequenz wiederholt. Die zweite Frequenz ist bevorzugt geringer als die erste Frequenz und beträgt besonders bevorzugt nur einen Bruchteil der ersten Frequenz. Die Wiederholungsrate der Spannungspulse liegt bevorzugt zwischen 1 Hz und 10 kHz, besonders bevorzugt zwischen 25 Hz und 250 Hz.
• – Anlegen einer Wechselspannung an eine dritte Elektrode des Elektrochirurgieinstruments und eine vierte Elektrode des Elektrochirurgiesystems zum elektrochirurgischen Schneiden und Koagulieren. Bevorzugt hat die Wechselspannung eine erste Frequenz. Die erste Frequenz der Wechselspannung kann beispielsweise zwischen 100 kHz und 2 MHz und bevorzugt zwischen 200 kHz und 400 kHz liegen.

The invention further relates to a method for operating an electrosurgical system with an electrosurgical instrument and with at least four electrodes. The method comprises the method steps:

• - Arranging the electrosurgical instrument in a liquid.
• - Applying at least one DC voltage pulse and / or AC pulse to a first and second electrode of the electrosurgical instrument, wherein a peak amplitude of the voltage applied to the electrosurgical system voltage and / or energy delivery to the electrosurgical system are set such that the electrosurgical instrument short-lived gas bubbles in one in operation with the Electrosurgical instrument generates in contact fluid. Preferably, the at least one alternating voltage pulse has a first frequency. The first frequency of the alternating voltage pulse may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz. Preferably, the voltage pulses are repeated at a second frequency. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The repetition rate of the voltage pulses is preferably between 1 Hz and 10 kHz, more preferably between 25 Hz and 250 Hz.
• - Applying an AC voltage to a third electrode of the electrosurgical instrument and a fourth electrode of the electrosurgical system for electrosurgical cutting and coagulation. Preferably, the AC voltage has a first frequency. The first frequency of the alternating voltage may for example be between 100 kHz and 2 MHz and preferably between 200 kHz and 400 kHz.

• – Anordnen einer ersten Elektrode eines Elektrochirurgieinstruments in der Nähe einer Benignen Prostatahyperplasie, insbesondere zwischen Prostatakapsel und Adenomgewebe.
• – Anlegen einer Wechselspannung an die erste Elektrode des Elektrochirurgieinstruments und eine zweite Elektrode des Elektrochirurgiesystems zum elektrochirurgischen Schneiden und Koagulieren. Bevorzugt hat die Wechselspannung eine erste Frequenz. Die erste Frequenz der Wechselspannung kann beispielsweise zwischen 100 kHz und 2 MHz und bevorzugt zwischen 200 kHz und 400 kHz liegen.
• – Anlegen wenigstens eines Gleichspannungspulses und/oder Wechselspannungspulses an das Elektrochirurgieinstrument, wobei eine Spitzenamplitude der an das Elektrochirurgieinstrument angelegten Spannungspulse und/oder eine Energieabgabe an das Elektrochirurgiesystem derart eingestellt sind, dass das Elektrochirurgieinstrument kurzlebige Gasblasen in einer im Betrieb mit dem Elektrochirurgieinstrument in Kontakt stehenden Flüssigkeit erzeugt, die beim Zerfallen insbesondere eine Trennung von Prostatakapsel und Adenomgewebe bewirken. Bevorzugt wird der wenigstens eine Gleichspannungspuls und/oder Wechselspannungspuls an wenigstens zwei Elektroden des Elektrochirurgieinstruments angelegt. Besonders bevorzugt wird eine Folge von Gleichspannungspulsen und/oder Wechselspannungspulsen angelegt.

The invention further relates to a method for treating Benign Prostatic Hyperplasia (BPH) with the aid of an electrosurgical system and with the method steps:

• Arranging a first electrode of an electrosurgical instrument in the vicinity of benign prostate hyperplasia, in particular between prostate capsule and adenoma tissue.
• - Applying an AC voltage to the first electrode of the electrosurgical instrument and a second electrode of the electrosurgical system for electrosurgical cutting and coagulation. Preferably, the AC voltage has a first frequency. The first frequency of the alternating voltage may for example be between 100 kHz and 2 MHz and preferably between 200 kHz and 400 kHz.
• - Applying at least one DC voltage pulse and / or AC pulse to the electrosurgical instrument, wherein a peak amplitude of the voltage applied to the electrosurgical instrument voltage pulses and / or energy delivery to the electrosurgical system are set such that the electrosurgical instrument short-lived gas bubbles in a standing in use with the electrosurgical instrument in contact fluid produced, which cause the disintegration in particular a separation of prostate capsule and adenoma tissue. Preferably, the at least one DC voltage pulse and / or AC voltage pulse is applied to at least two electrodes of the electrosurgical instrument. Particularly preferably, a sequence of DC pulses and / or AC pulses is applied.

• – Betreiben des Aktuators, derart dass sich dieser mit einer Geschwindigkeit relativ zum restlichen Elektrochirurgieinstrument vor und zurück bewegt, so dass kurzlebige Gasblasen in Folge von Kavitation in der mit dem Aktuator in Kontakt stehenden Flüssigkeit entstehen.

As an alternative or in addition to the application of at least one DC voltage pulse and / or AC voltage pulse, the method for treating Benign Prostatic Hyperplasia may comprise the following method step:

• Operating the actuator so that it moves back and forth at a speed relative to the rest of the electrosurgical instrument so that short-lived gas bubbles are created as a result of cavitation in the fluid in contact with the actuator.

As a result, gas bubbles can be generated mechanically as a result of cavitation, which, in addition or as an alternative to the gas bubbles produced by the pulsed plasma discharges, decays and generates further pressure surges which damage the benign prostatic hyperplasia (BPH), in particular cause a separation of prostate capsule and adenoma tissue.

In one embodiment of the method for treating Benign Prostatic Hyperplasia (BPH), the method additionally comprises the step of supplying a fluid near Benign Prostatic Hyperplasia. This process step takes place parallel to the application of the alternating voltage and can also be carried out before the AC voltage is applied. The fluid may include, for example, purisols, saline, medicaments, a cooling fluid, marking fluid, or other fluids used to treat body tissue.

The invention further relates to the use of an electrosurgical system according to the invention for carrying out one of the methods according to the invention.

The invention will now be explained in more detail with reference to embodiments schematically illustrated in the figures. From the figures shows:

1 a schematic representation of a first embodiment of an electrosurgical system;

2a a further schematic representation of the electrosurgical system of 1 ;

2 B a schematic representation of the electrosurgical system of 1 with a first housing surface shape;

2c a schematic representation of the electrosurgical system of 1 with a second housing surface shape;

3a a schematic representation of the electrosurgical system of 2c when generating a gas bubble;

3b a schematic representation of the electrosurgical system of 2c in which the gas bubble increases;

3c a schematic representation of the electrosurgical system of 2c wherein the gas bubble has decayed and a pressure wave and smaller gas bubbles are spreading;

4 a schematic representation of a second embodiment of an electrosurgical system with an actuator;

5 a schematic representation of a third embodiment of an electrosurgical system with a supply line;

6 a schematic representation of a fourth embodiment of an electrosurgical system with a large-area neutral electrode;

7 a schematic representation of a first embodiment of a voltage applied to the electrodes voltage curve, the development of a gas bubble generated by the electrodes in a liquid, as well as the wave motion in the liquid over time;

8th a schematic representation of a second embodiment of a voltage applied to the electrodes voltage waveform over time;

9 a schematic representation of an embodiment of an electrosurgical instrument;

10 a schematic representation of a fifth embodiment of an electrosurgical system with four electrodes;

11a a schematic representation of an embodiment of the first and second electrodes of the electrosurgical system of the 10 applied voltage curve over time;

11b a schematic representation of an embodiment of the third and fourth electrode of the electrosurgical system of the 10 applied voltage curve over time;

12 a schematic block diagram representation of a first embodiment of a method for operating an electrosurgical system;

13 a schematic block diagram representation of a second embodiment of a method for operating an electrosurgical system;

14 a schematic block diagram of an embodiment of a method for the treatment of benign prostatic hypoplasia (BPH);

15 a schematic block diagram representation of an embodiment of a method for operating a electrosurgical system with four electrodes.

1 shows a first embodiment of an electrosurgical system 10 with an electrosurgical instrument 12 , a high voltage power supply unit 14 and a controller 18 , The high voltage supply unit 14 is in this case a high voltage generator 16 , which is designed to generate both high-frequency AC voltage, as well as DC voltages. The high voltage generator 16 has for this purpose an AC voltage generator and a DC voltage generator (not shown). Alternatively, the high voltage supply unit may also be a DC voltage generator or an AC voltage generator. The electrosurgical system 10 is used in the resection of body tissue of a body.

The electrosurgical instrument 12 has in the first embodiment of the electrosurgical system 10 a first electrode 20 and a second electrode 22 , The two electrodes 20 and 22 are at the distal end of a housing 32 of the electrosurgical instrument 12 arranged. Alternatively, as in the fourth embodiment of the electrosurgical system 10 in 6 shown, the electrosurgical instrument 12 also only a first electrode 20 and the second electrode 22 can be used as a neutral electrode at a distance to the first electrode 20 be arranged (s. 6 ). In particular, the neutral electrode is in operation of the electrosurgical system 10 preferably on a body surface of one with the electrosurgical system 10 arranged to be treated body. The first electrode 20 is used to generate short-lived gas bubbles as well as for electrosurgical cutting and coagulation of body tissue. This is the first electrode 20 and the second electrode 22 with the high voltage generator 16 electrically connected. The high voltage generator 16 supplies the two electrodes 20 and 22 with a repetitive series of DC pulses and AC pulses with different pulse durations, voltage amplitudes and frequencies. In a use of the electrosurgical system 10 A DC voltage having a voltage amplitude v1 is applied to the first and second electrodes for a duration t1 followed by an AC voltage having a voltage amplitude v2 and a frequency f1 for a duration t2 followed by a voltage pause for a duration t3 (see FIG. 7 ). This sequence of voltage pulses is repeated at a frequency F = 1 / (t1 + t2 + t3) = f2, which is preferably between 1 Hz and 10 kHz. The first frequency f1 of the alternating voltage pulses can be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz.

The high voltage generator 16 is with the controller 18 connected. The control unit 18 controls the high voltage generator 16 so that over the electrodes 20 and 22 a certain amount of energy is released.

The electrosurgical instrument 12 is in operation in a liquid 24 , So that the first electrode 20 in contact with the liquid 24 stands. In operation, a train of DC pulses and / or AC pulses is applied to the electrodes 20 and 22 created. As a result, a current flows between the two electrodes 20 and 22 , which generates a plasma discharge with correspondingly high energy output. This creates a gas bubble 34a ( 3 and 7 ). When the energy output is stopped, the gas bubble breaks down 34b and 34c ( 3 and 7 ). After generating the plasma discharge to produce a gas bubble, another voltage output, in particular a continuous alternating voltage pulse, can be carried out for cutting or coagulating tissue.

At the first electrode 20 will deliver in this first embodiment of the electrosurgical system DC pulses with a power between 1 kW and 5 kW. The pulses can also have a power of up to 10 kW. The pulse duration of the pulses is preferably less than 1 ms, more preferably between 100 ns and 100 μs. The sequence of voltage pulses can be repeated at a repetition rate F between 1 Hz and 10 kHz. For example, the voltage sequence can also be delivered at a repetition rate F between 25 Hz and 250 Hz. This makes it possible to generate pulsed plasma discharges.

The electrosurgical system 10 is designed by means of the electrosurgical instrument 12 short lived gas bubbles 34a in the liquid 24 to create. In the first embodiment of the electrosurgical system 10 of the 1 controls the controller 18 the high voltage generator 16 such that first a DC pulse for the period t1 at the electrodes 20 and 22 is created. The DC pulse is followed by an AC pulse having a first frequency f1 for a time t2 (FIG. 7 ). The first frequency f1 is greater than the repetition rate F = 1 / (t1 + t2 + t3) = f2 with which the sequence of voltage pulses is repeated. In this first exemplary embodiment, the first frequency f1 is preferably between 200 kHz and 400 kHz. The peak amplitude v1 of the DC voltage pulses is set such that, periodically at the repetition rate F, ie at the second frequency f2, plasma discharges from the first electrode 20 go out and in this way the short-lived gas bubbles 34a in operation with the first electrode 20 in contact with liquid 24 arise. Alternatively or additionally, the energy output can be set such that periodically plasma discharges from the first electrode 20 go out and in this way the short-lived gas bubbles 34a in operation with the first electrode 20 in contact with liquid 24 arise.

Preferably, the pulse duration or time duration t1 of the DC voltage pulses is less than 1 ms and the pulse duration or time duration t2 of the AC voltage pulses is greater than 1 ms. It is also possible alternately AC pulses with different amplitudes, pulse durations and frequencies are delivered. In this case, two, three or more different AC pulses may alternate. It can also alternate different DC pulses with different AC pulses. The voltage pulses can also overlap in time. The voltage pulses may have a pulse power between 100 W and 10 kW, a pulse duration between 10 μs and 10 ms and a repetition rate F with a second frequency f2 between 1 Hz and 10 kHz.

The short-lived gas bubbles 34a generate pressure surges or pressure waves during decay 35 ( 3 ), which can damage body tissues and therefore can aid in the treatment of body tissue.

The electrosurgical system 10 Therefore, three effects are exploited to damage body tissue or to separate levels of operation between different types of tissue. First, the body tissue may be due to an elevated temperature around the first electrode 20 be vaporized or cut. Second, the body tissue can be coagulated. Third, there is a mechanical breakdown of the body tissue by pressure surges, which are due to the implosions or the disintegration of the short-lived gas bubbles 34a decline. Another way to damage or mechanically dissect the body tissue is by placing a shaft (not shown) of the electrosurgical instrument 12 pressed against the body tissue.

In an alternative operating mode ( 8th ) of the electrosurgical system 10 of the 1 controls the controller 18 the high voltage generator 16 such that it modulates a continuous alternating voltage having a first frequency f1 by a second function with a second frequency f2. The second function serves as a modulation function. The modulation function can also be, for example, a pulse wave oscillation with a predetermined pulse length, pulse amplitude and pulse frequency. These may be different than the AC voltage excited at the first frequency f1. In 8th the function is modulated with the first frequency f1 having a modulation function with the second frequency f2. The modulation function in this case is a function with a second frequency f2 periodically repeating DC pulses with a predetermined pulse duration. During the pulse duration or time duration t2 of the modulation function, the alternating voltage is amplified at the first frequency f1 (FIG. 8th ). When the AC voltage through a Modulation function is modulated, the repetition rate F of the voltage pulses equal to the frequency f2 of the modulation function. In modulating, a peak amplitude is preferably set such that periodically plasma discharges from the first electrode 20 go out and in this way short-lived gas bubbles 34a in operation with the first electrode 20 in contact with liquid 24 arise. This mode of operation also makes it possible to achieve the three effects for the treatment of the tissue.

2a shows the electrosurgical system 10 with the electrosurgery instrument 12 of the embodiment of 1 in an alternative representation.

In the illustration shown, only one line between the high voltage generator 16 and the electrosurgical instrument 12 located. This is to serve here and in the following figures only to simplify the presentation and is not to be understood as a limitation to a single line. There may also be more than one or two lines between the high voltage generator 16 and the electrosurgical instrument 12 run.

The electrodes 20 and 22 are in the case 32 of the electrosurgical instrument 12 arranged and extend to the distal end of the housing 32 , The electrodes 20 and 22 are made of steel. Alternatively, electrodes can also be used 20 . 22 can be used, which have an electrically conductive material composition or an electrically conductive material, for example a metal such as platinum, copper, a metallic alloy or other electrically conductive materials.

Between the electrodes 20 and 22 is arranged an electrical insulation, which is the first electrode 20 from the second electrode 22 electrically isolated (not shown). In this embodiment, the electrical insulation is an electrically non-conductive insulating layer (not shown). The insulating layer consists of a polyamide or a ceramic. Alternatively, the electrical insulation may also include one or more non-electrically conductive plastics such as polyamide or the like.

The distal end of the case 32 is from a surface 33 educated. In this embodiment, the surface is 33 flat. The electrodes 20 and 22 extend to the surface 33 and form part of this. The electrical insulating layer extends to the electrodes 20 and 22 parallel to the surface 33 ,

In this embodiment, the electrodes have 20 and 22 a rectangular cross-section. The cross sections of the electrodes 20 and 22 may also have other shapes, such as square, hexagonal, octagonal, circular or other shape. The electrodes 20 and 22 can also be arranged coaxially, so that, for example, the first electrode 20 within the second electrode 22 is arranged (not shown). One or more coaxially arranged electrodes may for example also be annular. The rectangular cross-sectional area of the electrodes 20 and 22 optimizes the utilization of the cross-sectional area to enable a particularly efficient energy transport with the lowest possible resistance per length.

The electrosurgical instrument 12 may have an electrically non-conductive insulating sheath and / or a metallic shield as the housing wall of the housing 32 have (not shown). The insulation cover can be along the length of the housing 32 and extend beyond the distal end thereof (not shown). The insulation sheath can serve to direct the pressure waves generated by the decaying gas bubbles.

2 B shows a schematic representation of a lateral section through the housing 32 of the electrosurgical instrument 12 of the 2a , The distal ends of the electrodes 20 and 22 form part of the flat, even surface 33 ,

2c shows a schematic representation of a lateral section through the housing 32 a further embodiment of an electrosurgical instrument 12 similar to that of 2a , In contrast to the embodiment of the electrosurgical instrument 12 of the 2a is the surface 33 ' curved. In this embodiment, the surface has 33 ' a parabolic cylindrical shape. Alternatively, the surface may also have a hyperbolic-parabolic, parabolic, hemispherical, semi-spherical shape or other shape that enhances steering of the pressure waves generated by the disintegrating gas bubbles.

Also in this embodiment form the distal ends of the electrodes 20 and 22 a part of the flat, even surface 33 , Alternatively, the electrodes can 20 and 22 even to the distal end of the case 32 of the electrosurgical instrument 12 extend (not shown).

3 shows the formation of a gas bubble 34a and a first pressure wave 35 ( 3a ), the enlargement of the gas bubble 34b ( 3b ) and the formation of directed pressure waves 35 with decaying smaller gas bubbles 34c ( 3c ).

3a shows how a gas bubble through a short voltage pulse with a high voltage 34a on the surface 33 ' of the housing 32 between the first electrode 20 and the second electrode 22 is produced. The gas bubble 34a results from a plasma discharge between the electrodes 20 and 22 , The plasma discharge also generates a pressure wave in the electrosurgery instrument 12 surrounding liquid 24 ,

3b shows how the gas bubble 34b increases while an AC voltage between the electrodes 20 and 22 is applied, which can be used for cutting or coagulating. The surface 33 ' of the housing 32 of the electrosurgical instrument 12 is curved so that the gas bubble 34b in one direction away from the electrosurgical instrument 12 increased.

3c shows a time shortly after the gas bubble 34b imploded or disintegrated. The gas bubble 34b is in smaller gas bubbles 34c decay and has pressure waves 35 generated due to the surface shape of the surface 33 ' of the housing 32 in one direction away from the electrosurgical instrument 12 be steered. The surface 33 ' may also be formed the pressure waves 35 to focus. Dealing with the pressure waves 35 moving gas bubbles 34c disintegrate after a short period of time and release new pressure waves 35 off (not shown).

4 shows a second embodiment of an electrosurgical system 10 with an actuator 26 , The second embodiment of the electrosurgical system 10 differs from the first embodiment of the in 1 shown electrosurgical system 10 essentially by the additional actuator 26 ,

The actuator 26 is with the high voltage generator 16 electrically connected and is supplied by this with an AC voltage. In this embodiment, the actuator is 26 over two lines with the high voltage generator 16 connected. The actuator 26 can also work with more than two wires with the high voltage generator 16 be connected. The control unit 18 controls the supply of the actuator 26 with energy.

In operation of the electrosurgical system 10 is the actuator 26 in the liquid 24 arranged. If the actuator 26 is supplied with an AC voltage, it moves at a speed relative to the remaining electrosurgical instrument 12 back and forth. This movement is generated in the liquid 24 mechanical waves and, if applicable, as long as conditions are fulfilled for gas bubbles resulting from cavitation.

In this second embodiment of the electrosurgical system 10 controls the controller 18 the high voltage generator 16 such that this an AC voltage to the actuator 26 so that it moves at such a speed that short-lived gas bubbles as a result of cavitation in the liquid 24 arise. This is a consequence of the reduced static pressure in the liquid 24 at a high speed of movement of the actuator 26 , When the static pressure drops below the evaporation pressure of the liquid, gas bubbles are formed. These are entrained with the flow of liquid and collapse or disintegrate abruptly, so that pressure surges or pressure waves form. These pressure surges can contribute to damage to body tissue and to the treatment of body tissue or support the treatment. Furthermore, these pressure surges can also serve to separate levels of operation between different types of tissue.

The control unit 18 can in the second embodiment of the electrosurgical system 10 also the high voltage generator 16 such that one to the electrodes 20 and 22 applied continuous AC voltage is modulated by a modulation function with a second frequency f2 ( 8th ). The second frequency f2 is smaller in this second embodiment than the first frequency f1 and preferably between 1 Hz and 10 kHz, ie, the second frequency f2 is only a fraction of the first frequency f1. A peak amplitude of the AC voltage is set such that periodically plasma discharges from the first electrode 20 go out and in this way short-lived gas bubbles 34a in operation with the first electrode 20 in contact with liquid 24 arise.

This can cause gas bubbles 34a with the help of the electrodes 20 and 22 , as well as by the actuator 26 be generated. This makes it possible to intensify the treatment by means of pressure surges.

In an alternative use of the electrosurgical system 10 According to the second embodiment is a continuous alternating voltage between the electrodes 20 and 22 created. This makes it possible to cut and coagulate with the help of the electrodes. The actuator 26 is operated with short voltage pulses. As a result, the actuator generates 26 Gas bubbles due to cavitation.

The two electrodes 20 . 22 and the actuator 26 can be operated independently of each other.

The electrosurgical system 10 For example, it may have a switch or other user interface through which the user can control or activate the controller (not shown). This allows the user to control, for example, whether only the electrodes, only the actuator or both are supplied with voltage and when Power supply is activated or deactivated (not shown).

Other alternative modes of operation of the second embodiment of the electrosurgical system 10 as described in the disclosure of this text may be used. In particular, the control unit 18 the high voltage generator 16 such that it modulates the first frequency f1 by a second function with a second frequency f2. The second function then serves as a modulation function. In modulating, a peak amplitude is set such that periodically plasma discharges from the first electrode 20 go out and in this way short-lived gas bubbles 34a in operation with the first electrode 20 in contact with liquid 24 arise.

In 5 is a third embodiment of the electrosurgical system 10 shown that a fluid pump 28 and a supply line 30 having. The third embodiment of the electrosurgical system 10 differs from the first embodiment of the in 1 shown electrosurgical system 10 So essentially by the additional fluid pump 28 and the supply line 30 ,

The fluid pump 28 is with the high voltage generator 16 electrically connected and is powered by this. Alternatively, the fluid pump 28 be supplied by another source of energy (not shown). The control unit 18 controls the high voltage generator 16 to transfer the energy to the electrodes 20 and 22 as well as to the fluid pump 28 to coordinate in time. During operation of the fluid pump 28 pumps this fluid from a fluid reservoir (not shown).

The feed line 30 is with the fluid pump 28 and the electrosurgical instrument 12 connected. During operation, the supply line is used 30 to that of the fluid pump 28 fluid pumped from the fluid reservoir into the fluid 24 respectively. In the third embodiment of the electrosurgical system 10 the fluid contains purisols or saline. However, the fluid may also contain, for example, medicaments, a cooling fluid, marking fluid or other fluids used to treat body tissue.

6 shows the fourth embodiment of the electrosurgical system 10 which is a neutral second electrode 22 that is outside the electrosurgical device 12 is arranged. The fourth embodiment of the electrosurgical system 10 differs from the first embodiment of the in 1 shown electrosurgical system 10 essentially in that the second electrode 22 separated from the first electrode 20 and outside the electrosurgical instrument 12 is arranged.

In this fourth embodiment, a large neutral second area electrode 22 placed outside of a body in contact with the body, leaving a circuit between the first electrode 20 and second electrode 22 over the liquid 24 can be closed. In this way, a current flows through a larger part of the body, its highest energy density near the first electrode 20 lies.

7 shows a schematic representation of one of the electrodes 20 and 22 applied exemplary voltage waveform over time for a mode of operation of the electrosurgical system 10 ( 7e ). Furthermore, the development of the gas bubble 34a . 34b . 34c and 34d in the 7a to 7d shown after a DC pulse has been delivered. Furthermore, in addition, the direction of the wave motion 36 indicated in the liquid over time.

In this exemplary voltage curve, three voltage pulse shapes are applied to the electrodes 20 and 22 created. First, a DC voltage pulse having a voltage amplitude v1 is applied for a period of time t1, followed by an AC voltage pulse having a voltage amplitude v2 and a first frequency f1 for a time t2, followed by a voltage pause for a period t3 in which no voltage pulse is applied.

In 7a a plasma discharge is generated which coincides with the voltage amplitude v1 of the DC voltage. This creates a gas bubble 34a , This creates a wave motion 36 towards the electrodes 20 and 22 ,

7b shows the gas bubble 34b after the DC pulse with the peak amplitude v1 is turned off and the electrodes 20 and 22 continuously deliver energy with the AC voltage at the first frequency f1 to cut or coagulate surrounding tissue. The gas bubble 34b grows due to the inertia of the water even after the DC pulse is turned off (s. 7b ) and finally disintegrates (s. 7c ). The disintegration of the gas bubble creates a pressure wave away from the electrodes 20 and 22 (S. 7b to 7d ). The time duration t2 is orders of magnitude greater than the time duration t1. The structure and decay of the gas bubbles is generally much shorter than the time t2 for cutting or coagulation.

By the generation and disintegration of the gas bubbles 34a to 34d Pressure surges or pressure waves are generated, which damage body tissues can and can be used to treat body tissue.

8th shows a schematic representation of a second embodiment of a to the electrodes 20 and 22 applied voltage curve over time. The first frequency f1 is modulated by a second function with a second frequency f2. The second function serves as a modulating function that modulates the first frequency f1 with periodically repeating DC pulses having a predetermined pulse duration at a frequency f2.

9 shows an embodiment of an electrosurgical instrument 12 , The electrosurgical instrument 12 has a housing 32 to which a first electrode 20 and a second electrode 22 , as well as an actuator 26 are arranged.

The electrosurgical instrument 12 can as in the descriptions too 1 and 4 described, operated. In contrast to the embodiment of 4 is the actuator 26 not here in the middle between the first electrode 20 and second electrode 22 arranged but next to the electrodes 20 and 22 ,

The actuator 26 can be powered by an AC voltage so that it moves at a speed relative to the remaining electrosurgical instrument 12 in the directions of movement 38 can move. As a result, gas bubbles can be generated at sufficiently high speeds as a result of cavitation.

10 shows a fifth embodiment of an electrosurgical system 10 , In contrast to the first embodiment of the 1 has the fifth embodiment of the electrosurgical system 10 four electrodes, namely the first electrode 20 , the second electrode 22 , the third electrode 23 and the fourth electrode 25 ,

The first three electrodes 20 . 22 and 23 are in this embodiment in the electrosurgical instrument 12 arranged. The fourth electrode 25 is as an external electrode near the distal end of the electrosurgical instrument 12 arranged. Alternatively, the fourth electrode 25 also be arranged as a neutral electrode on a body surface. A possible mode of operation of the electrosurgery system 10 according to the fifth embodiment is based on the in the 11a and 11b explained voltage waveforms explained in more detail.

The at the first electrode 20 and the second electrode 22 applied voltage is determined by the in 11a shown voltage waveform shown. The at the third electrode 23 and fourth electrode 25 applied voltage is determined by the in 11b shown voltage waveform shown.

11a shows a periodically repeating with the repetition rate F DC pulse. The DC pulse has a pulse duration or duration t3 and is used to generate a plasma discharge and from this resulting short-lived gas bubbles, which generate pressure waves during decay.

11b shows an alternating voltage pulse repetitively repeated at the repetition rate F at a first frequency f1. The AC voltage pulse corresponds to an AC voltage applied continuously for the pulse duration t1. The AC voltage is used for cutting and coagulating tissue.

It is also possible at the same time DC voltage pulses and AC voltage pulses or combinations of the respective voltage pulses to the electrodes 20 and 22 such as 23 and 25 be created. The systems consisting in each case of two electrodes in this exemplary embodiment can be operated independently of one another.

It is also possible to generate gas bubbles periodically by means of periodically delivered DC pulses, while the AC voltage used for cutting and coagulation is continuous to the first and second electrodes 20 and 22 is created. The gas bubbles may also be selectively generated, for example, by means of a sensor system that detects certain tissue types and, in response, initiates the delivery of a DC pulse (not shown). Furthermore, the gas bubbles can also be generated manually, for example by a user manually activating the voltage pulses via a switch or another user interface (not shown).

12 shows a block diagram representation of a first embodiment of a method for operating an electrosurgical system with an electrosurgical instrument. The method comprises the method steps:
100 Placing the electrosurgical instrument in a liquid,
110 Applying at least one DC or AC pulse to a first electrode of the electrosurgical instrument and a second electrode of the electrosurgical system, wherein a peak amplitude of the voltage applied to the electrosurgical system voltage and / or a power delivery to the electrosurgical system are set such that the electrosurgical instrument in a short-lived gas bubbles in operation generated with the electrosurgical instrument in contact liquid. Preferably, the at least one AC voltage pulse a first frequency. The first frequency of the alternating voltage pulse may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz. Preferably, the voltage pulses are repeated at a second frequency. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The repetition rate F of the voltage pulses is preferably between 1 Hz and 10 kHz, more preferably between 25 Hz and 250 Hz.
120 Applying an AC voltage to a first or further electrode of the electrosurgical instrument and a second electrode of the electrosurgical system for electrosurgical cutting and coagulation. Preferably, the AC voltage has a first frequency between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz.

The method according to the embodiment of the 12 For example, it can be used to treat an electrosurgical system, such as in 1 or 4 to 6 is shown to operate.

13 shows a block diagram representation of a second embodiment of a method for operating an electrosurgical system, as shown for example in 4 is shown. The method comprises the method steps:
200 Placing the electrosurgical instrument in a liquid,
210 Applying an alternating voltage at a first frequency to the first electrode of the electrosurgical instrument and the second electrode of the electrosurgical system for electrosurgical cutting and coagulation,
220 Operating the actuator so that it moves back and forth at a speed relative to the rest of the electrosurgical instrument, resulting in short-lived gas bubbles resulting from cavitation in the fluid in contact with the actuator.

Alternatively or in addition to step 220 the following step can be performed:
230 Applying at least one DC or AC pulse to a first electrode of the electrosurgical instrument and a second electrode of the electrosurgical system, wherein a peak amplitude of the voltage applied to the electrosurgical system voltage and / or a power delivery to the electrosurgical system are set such that the electrosurgical instrument in a short-lived gas bubbles in operation generated with the electrosurgical instrument in contact liquid. Preferably, the at least one alternating voltage pulse has a first frequency. The first frequency of the alternating voltage pulse may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz. Preferably, the voltage pulses are repeated at a second frequency. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The repetition rate F of the voltage pulses is preferably between 1 Hz and 10 kHz, more preferably between 25 Hz and 250 Hz.

14 FIG. 12 is a block diagram of one embodiment of a method for treating benign prostate hyperplasia (BPH) using an electrosurgical system and with the steps of:
300 Placing a first electrode of an electrosurgical instrument near a benign prostate hyperplasia,
310 Applying an AC voltage to the first electrode of the electrosurgical instrument and a second electrode of the electrosurgical system for electrosurgical cutting and coagulation. Preferably, the AC voltage has a first frequency. The first frequency of the alternating voltage may for example be between 100 kHz and 2 MHz and preferably between 200 kHz and 400 kHz.
320 Applying at least one DC voltage pulse and / or AC voltage pulse to the electrosurgical instrument, wherein a peak amplitude of voltage pulses applied to the electrosurgical instrument and / or energy delivery to the electrosurgical system are set such that the electrosurgical instrument generates short lived gas bubbles in a liquid in contact with the electrosurgical instrument which cause damage to benign prostatic hyperplasia during disintegration and, in particular, cause a separation of prostate capsule and adenoma tissue. Preferably, the at least one DC voltage pulse and / or AC voltage pulse is applied to at least two electrodes of the electrosurgical instrument. Particularly preferably, a sequence of DC pulses and / or AC pulses is applied.

Alternatively or in addition to step 320 the following step can be performed:
330 Operating the actuator such that it moves back and forth at a speed relative to the rest of the electrosurgical instrument so that short-lived gas bubbles are created as a result of cavitation in the fluid in contact with the actuator.

As a result, gas bubbles can be generated mechanically as a result of cavitation, which, in addition to or as an alternative to the gas bubbles produced by the pulsed plasma discharges, decays and generates further pressure surges which damage the benign prostatic hyperplasia and in particular cause a separation of the prostate capsule and adenoma tissue.

• – Zuführen eines Fluids in die Nähe der benignen Prostatahyperplasie aufweisen.

The method may additionally include the step

• - Having a fluid near benign prostatic hyperplasia.

The method step takes place parallel to the application of the alternating voltage and can also be carried out before the application of the alternating voltage. The fluid may include, for example, purisols, saline, medicaments, a cooling fluid, marking fluid, or other fluids used to treat body tissue.

15 FIG. 14 shows a block diagram representation of an embodiment of a method for operating a four-electrode electrosurgical system, as described in, for example, FIG 10 is shown. The method comprises the method steps:
400 Placing the electrosurgical instrument in a liquid,
410a Applying at least one DC and / or AC voltage pulse to a first electrode and a second electrode of the electrosurgical instrument, wherein a peak amplitude of the voltage applied to the electrosurgical instrument and / or energy delivery to the electrosurgical instrument are adjusted so that the electrosurgical instrument has short lived gas bubbles in operation generated with the electrosurgical instrument in contact liquid. Preferably, the at least one alternating voltage pulse has a first frequency. The first frequency of the alternating voltage pulse may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz. Preferably, the voltage pulses are repeated at a second frequency. The second frequency is preferably less than the first frequency and is particularly preferably only a fraction of the first frequency. The repetition rate F of the voltage pulses is preferably between 1 Hz and 10 kHz, more preferably between 25 Hz and 250 Hz.
410b Applying an AC voltage to a third electrode of the electrosurgical instrument and a fourth electrode of the electrosurgical system for electrosurgical cutting and coagulation. The first frequency of the AC voltage may be between 100 kHz and 2 MHz, for example between 200 kHz and 400 kHz.

The steps 410a and 410b can be performed parallel to each other or serially or in succession. It can also be one of the process steps 410a or 410b be carried out continuously and the other method step for a predetermined period of time, for example, t1 or t2. It can also be both process steps 410a and 410b each for a period t1 or t2 be executed. The process steps 410a and 410b can be executed in overlapping time periods. The voltage pulses applied to the first and second electrodes may be DC voltage pulses and / or AC voltage pulses. A DC voltage is preferably applied only for a short period of time, for example t1.

LIST OF REFERENCE NUMBERS

10

 An electrosurgical system

12

 Electrosurgical instrument

14

 High voltage power supply unit

16

 High voltage generator

18

 control unit

20

 first electrode

22

 second electrode

23

 third electrode

24

 liquid

25

 fourth electrode

26

 actuator

28

 fluid pump

30

 feed

32

 casing

33

 surface

34

 gas bubble

36

 wave motion

38

 Aktuatorbewegungsrichtungen

F

 repetition rate

f1

 first frequency

f2

 second frequency

V

 tension

v1

 Voltage amplitude of the DC voltage

v2

 Voltage amplitude of the AC voltage

t

 timeline

t1

 first period of time

t2

 second period of time

t3

 third period of time

Claims (16)

Electrosurgical system ( 10 ) for the resection of body tissue of a body, comprising: - an electrosurgical instrument ( 12 ), the at least one first electrode ( 20 ), which is designed for the electrosurgical cutting and coagulation of body tissue, - at least one second electrode ( 22 ), - a high voltage supply unit ( 14 . 16 ) connected to the first electrode ( 20 ) and the second electrode ( 22 ) is electrically connected and which is formed, these electrodes ( 20 . 22 ) with voltage pulses, and - a control unit ( 18 ) connected to the high voltage supply unit ( 14 . 16 ) and is adapted to release a release of energy via the electrosurgical instrument ( 12 ), characterized in that the electrosurgical system ( 10 ) is formed by means of Electrosurgical instruments ( 12 ) short-lived gas bubbles ( 34a . 34b . 34c . 34d ) in operation with the electrosurgical instrument ( 12 ) in contact ( 24 ) to create. Electrosurgical system ( 10 ) according to claim 1, characterized in that the voltage pulses are short DC voltage pulses and / or AC voltage pulses. Electrosurgical system ( 10 ) according to claim 1 or 2, characterized in that the control unit ( 18 ), the high voltage supply unit ( 14 . 16 ) such that the electrosurgical instrument ( 12 ) supplied with DC pulses and / or AC pulses, wherein a peak amplitude (v1) of the to the electrosurgical system ( 10 ) applied voltage and / or an energy delivery to the electrosurgical system ( 10 ) are set such that the electrosurgical instrument ( 12 ) short-lived gas bubbles ( 34a . 34b . 34c . 34d ) in operation with the electrosurgical instrument ( 12 ) in contact ( 24 ) generated. Electrosurgical system ( 10 ) according to one of claims 1 to 3, characterized in that the control unit ( 18 ), the high voltage supply unit ( 14 . 16 ) such that it emits a series of voltage pulses, so that the energy delivery to the electrosurgical system ( 10 ) is set such that periodically plasma discharges from the first electrode ( 20 ) and thus short-lived gas bubbles ( 34a . 34b . 34c . 34d ) in operation with the first electrode ( 20 ) in contact ( 24 ) and surrounding tissue is vaporized or coagulated. Electrosurgical system ( 10 ) according to one of claims 1 to 4, characterized in that the high voltage supply unit is adapted to continuously supply the electrodes with AC pulses, so that they are continuously supplied with an AC voltage having a first frequency (f1), which serves for cutting and coagulation and wherein the applied AC voltage is modulated by a second function as a modulation function at a second frequency (f2). Electrosurgical system ( 10 ) according to claim 5, characterized in that the second frequency (f2) is less than 200 kHz, in particular between 1 Hz and 10 kHz. Electrosurgical system ( 10 ) according to one of claims 1 to 6, characterized in that the cross-section of at least one of the electrodes ( 20 . 22 ) has at least four corners. Electrosurgical system ( 10 ) according to one of claims 1 to 7, characterized in that the electrosurgical system ( 10 ) one with the electrosurgery instrument ( 12 ) connected supply line ( 30 ) which is designed to be in use with the first electrode ( 20 ) in contact ( 24 ) to supply a fluid containing purisols and / or saline. Electrosurgical system ( 10 ) according to one of claims 1 to 8, characterized in that the electrosurgical system ( 10 ) is formed on the first electrode ( 20 ) To output voltage pulses with a power between 100 W and 10 kW in order to generate pulsed plasma discharges. Electrosurgical system ( 10 ) one of claims 1 to 9, characterized in that the electrosurgical system ( 10 ) is formed on the first electrode ( 20 ) To emit voltage pulses having a pulse duration between 100 ns and 100 μs and a repetition rate (F) between 1 Hz and 10 kHz in order to generate pulsed plasma discharges. Electrosurgical system ( 10 ) one of claims 1 to 10, characterized in that the electrosurgical system ( 10 ) is formed by the disintegration of the gas bubbles resulting pressure waves in a direction away from the electrosurgical instrument ( 12 ) to steer. Electrosurgical system ( 10 ) according to one of claims 1 to 11, characterized in that the electrosurgical instrument ( 12 ) an actuator ( 26 ), which in operation in the liquid ( 24 ) and is formed at a speed relative to the remaining electrosurgical instrument ( 12 ) to move back and forth so that short-lived gas bubbles ( 34a . 34b . 34c . 34d ) due to cavitation in the with the actuator ( 26 ) in contact ( 24 ) arise. Method for operating an electrosurgical system ( 10 ) with an electrosurgical instrument ( 12 ) and the steps of: arranging the electrosurgical instrument ( 12 ) in a liquid ( 24 ), - applying at least one DC voltage and / or AC voltage pulse to a first electrode ( 20 ) of the electrosurgical instrument ( 12 ) and a second electrode ( 22 ) of the electrosurgical system ( 10 ), wherein a peak amplitude (v1) of the to the electrosurgical system ( 10 ) applied voltage and / or an energy delivery to the electrosurgical system ( 10 ) are set such that the electrosurgical instrument ( 12 ) short-lived gas bubbles ( 34a . 34b . 34c . 34d ) in operation with the electrosurgical instrument ( 12 ) in contact ( 24 ) generated, Applying an alternating voltage to a first or further electrode ( 20 ) of the electrosurgical instrument ( 12 ) and a second electrode ( 22 ) of the electrosurgical system ( 10 ) for electrosurgical cutting and coagulation. A method according to claim 13, characterized in that a continuous sequence of alternating voltage pulses to the first ( 20 ) and second electrode ( 22 As a result, a continuous alternating voltage having a first frequency (f1) is applied, and the continuous alternating voltage is modulated by a second function as a modulation function at a second frequency (f2), so that a peak amplitude of the voltage applied to the electrosurgical system ( 10 ) applied voltage and / or an energy delivery to the electrosurgical system ( 10 ) are set such that the electrosurgical instrument ( 12 ) short-lived gas bubbles ( 34a . 34b . 34c . 34d ) in operation with the electrosurgical instrument ( 12 ) in contact ( 24 ) generated. Method for operating an electrosurgical system ( 10 ) according to claim 12 and with the method steps: - arranging the electrosurgical instrument ( 12 ) in a liquid ( 24 ), - applying an alternating voltage (V) with a first frequency (f1) to the first electrode ( 20 ) of the electrosurgical instrument ( 12 ) and the second electrode ( 22 ) of the electrosurgical system ( 10 ) for electrosurgical cutting and coagulation, - operating the actuator ( 26 ), so that this at a speed relative to the remaining electrosurgical instrument ( 12 ) back and forth moves that short-lived gas bubbles ( 34a . 34b . 34c . 34d ) due to cavitation in the with the actuator ( 26 ) in contact ( 24 ) arise. Method for operating an electrosurgical system ( 10 ) with an electrosurgical instrument ( 12 ) with at least four electrodes ( 20 . 22 . 23 . 25 ) and the steps of: arranging the electrosurgical instrument ( 12 ) in a liquid ( 24 ), - applying at least one DC voltage pulse and / or AC voltage pulse to a first ( 20 ) and second electrode ( 22 ) of the electrosurgical instrument ( 12 ), wherein a peak amplitude (v1) of the to the electrosurgical system ( 10 ) applied voltage (V) and / or an energy delivery to the electrosurgical system ( 10 ) are set such that the electrosurgical instrument ( 12 ) short-lived gas bubbles ( 34a . 34b . 34c . 34d ) in operation with the electrosurgical instrument ( 12 ) in contact ( 24 ), - application of an alternating voltage (V) to a third electrode ( 23 ) of the electrosurgical instrument ( 12 ) and a fourth electrode ( 25 ) of the electrosurgical system ( 10 ) for electrosurgical cutting and coagulation.

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