Therapeutic apparatus and control method

Abstract

A treatment apparatus and a control method. A treatment device (10) according to the invention comprises an instrument (11) connected to a power supply (12). The instrument (11) and the device (12) can control each other. The generator can be activated in a first or second type of operation by means of an activation device (24) provided or otherwise provided on the instrument (11). The instrument (11) comprises a variable switch (30) to direct the power provided by the generator to the first or second electrode pair (20 / 21) or (22 / 21). The variable switch (30) is controlled by the generator (12). This provides the possibility of storing treatment progresses in the generator and executing them with the instrument 11 without the user changing the type of operation.

Description

Technical Field

[0001] The present invention relates to a therapeutic device which is particularly suitable for the coagulation and cutting of biological tissue of a human or animal patient. Background Art

[0002] Treatment devices for tissue coagulation and / or cutting are known in different configurations.

[0003] EP 3895642 A1 describes such a therapeutic device consisting of a generator and an instrument, wherein the generator is configured to generate a voltage sufficient for coagulating biological tissue. A transformer is provided in the instrument, which is connected to the cutting electrode and is configured to generate a voltage sufficient for cutting tissue by means of a conversion from a voltage configured for coagulation. An electric switch that can be activated by means of a button provided on the instrument is used to activate the electrode arrangement. With this button or an alternative second button, an activation signal is generated for the generator to turn the generator on and off.

[0004] From EP 1287788 A1 a therapeutic device with a generator and an apparatus is known, wherein the apparatus comprises a switch in order to alternately connect the first or second electrode pair to the generator. The activation of the generator and the apparatus is controlled by an activation device in the form of a manual or foot switch. Thus, the power factor of the generator is switched.

[0005] Additional therapeutic devices are known from EP 1 545 360 A1, US 2010 / 0137854 A1, EP 1 599 146 B1 and EP 1 711 116 B1. Summary of the invention

[0006] It is an object of the present invention to provide an improved therapeutic apparatus.

[0007] The treatment device according to the present invention comprises a generator and an instrument powered by the generator. The generator is configured to output a voltage according to a generator control signal, wherein the voltage is suitable for a first treatment mode, such as tissue coagulation, or alternatively suitable for a second treatment mode, such as tissue cutting. The generator is configured to switch between two indicated treatment modes. If necessary, the generator can also be switchable between other and / or multiple treatment modes.

[0008] The generator is configured to be controlled by means of a generator control signal defining a therapy mode. Furthermore, the generator is configured to output a variable switch control signal which controls a variable switch preferably arranged in the instrument in order to provide a voltage output by the generator and thus also a current provided by the generator to the electrodes (or respective electrode pairs) which is suitable for the respectively selected therapy mode.

[0009] In the present invention, a signal carrier is used to transmit a generator control signal and a variable switch control signal. The generator is configured to provide a signal carrier. The instrument is connected to the generator via a line and to the signal carrier so that the signal carrier is transmitted from the generator to the instrument. The signal carrier is preferably an alternating voltage in the sound frequency range of 20 Hz and 20 kHz, such as a square wave AC voltage. Preferably, the frequency of the signal carrier is approximately 2 kHz. The signal carrier can be an AC signal that alternates at an indicated frequency (e.g., alternates between positive and negative values). The positive and negative values ​​can have the same absolute value.

[0010] An activation device configured to generate a generator control signal can be assigned to the instrument. For this purpose, the activation device can be configured to apply different resistances to the AC signal for different desired operating modes. The resulting voltage is then the generator control signal, which is detected by the control device of the generator and used to control the generator.

[0011] Alternatively, the signal carrier can also be an alternating voltage signal with a suitable frequency (e.g. 20 Hz to 20 kHz, e.g. 2 kHz), wherein in the instrument or again in the activation device, different resistors that can be activated via a button can be applied together with the signal carrier. In this case, the resulting alternating current is the generator control signal, wherein the control device of the generator is configured to control the generator accordingly.

[0012] The activation device can be arranged in the instrument or in a separate operating part separate therefrom.

[0013] According to the invention, the apparatus of the treatment device comprises a variable switch circuit which connects the electrode provided for the first treatment mode or the electrode provided for the second treatment mode to the line from the generator. Thus, for both electrodes, a same counter-electrode can be provided which forms an electrode pair with the corresponding electrode of the selected treatment mode. The variable switch can also be configured to switch the electrode of the first treatment mode to a neutral electrode of the second treatment mode.

[0014] Depending on the selected treatment mode, the variable switch circuit is controlled by means of a variable switch control signal. The generator is configured to generate the variable switch control signal and apply it to the signal carrier. For example, the signal carrier may have a variable duty cycle so that the average value of the signal carrier alternating between positive and negative values ​​becomes a positive value or a negative value. Thus, a first average value may be assigned to the first treatment mode and a second average value may be assigned to the second treatment mode. The variable switch circuit may be configured to connect the first or second electrode to the line, and therefore to the generator, respectively, based on the detection of different average values ​​of the signal carrier. The average value of the signal carrier is then the variable switch signal.

[0015] The system according to the invention allows to control a variable switch provided in the instrument by means of a generator. The generator in turn is controlled by an activation device which can be arranged in the instrument or in a separate element (eg a pedal).

[0016] In the present invention, the treatment current is provided in a controlled manner only to the electrodes provided for the respective treatment. The variable switch provided in the apparatus is thereby controlled by means of a device comprising a generator. The variable switch is configured to connect only the electrodes or those electrodes associated with the selected mode in which the apparatus operates with the generator.

[0017] Since the variable switch controlled by the generator provides current only to the activated electrode, and no current flows through the electrode associated with the different mode, the generator voltage and / or the generator current can be detected particularly accurately and can be sensitively controlled in a closed loop. Based on the voltage and current output by the generator and the phase shift between the two, the output power can be determined. In addition, the tissue resistance can be calculated and adjusted as needed.

[0018] By means of a rapid alternating switching of the variable switch and a corresponding guidance of the generator voltage, an activation can be produced, wherein current is supplied to both electrodes simultaneously. For example, with a coagulation and cutting instrument, it is possible to pre-seal a vessel or another tissue in this way before performing a tissue cut in the context of cutting. If an artery or other vessel is clamped with a forceps-like instrument which also includes a cutting electrode, current can first be applied to the coagulation electrode, and the cutting can be performed in a delayed or slowed manner. This increases the safety of the treatment, since it is prevented that an artery that has not yet been completely sealed slips out of the closed forceps-like instrument.

[0019] A further advantage of the therapeutic device according to the invention is that no transformer is required in the instrument, whereby a particularly light and thin instrument with low technical effort can be provided.

[0020] Preferably, the generator is a high frequency generator and is configured to output an alternating voltage having a frequency between 100 kHz and 5 MHz. Preferably, the generator frequency is between 300 kHz and 600 kHz and can be varied with respect to its peak-to-peak voltage and, for example, different current and / or power limits. Furthermore, the generator can be configured to provide a modulated voltage, for example a voltage that is switched on and off, in order to obtain different desired crest factors.

[0021] The invention is particularly applicable to a forceps-like instrument with a non-movable cutting electrode, wherein the first treatment mode may be a coagulation mode. Coagulation electrodes are provided on two jaws in the forceps-like fork portion. One of the two electrodes may be considered a neutral electrode, while the other electrode of the other jaw is a designated coagulation electrode. The neutral electrode and the coagulation electrode form an electrode pair for tissue coagulation and / or tissue fusion.

[0022] The second treatment mode may be a cutting mode. In this mode, the immovable cutting electrode is activated. In turn, one of the two electrodes provided on the jaws may form a neutral electrode. It is also possible to configure the variable switching circuit so that the two electrodes provided on the jaws are electrically connected to each other in the cutting mode. In this mode, the electrode provided on the jaws is then the neutral electrode.

[0023] In principle, the invention is also applicable to other instruments, for example instruments having cutting and ablation functions or the like.

[0024] By using the concept according to the present invention, it is possible to ensure that the generator control signal is set to temporarily start after the variable switch control signal and temporarily end before the variable switch control signal. In doing so, it is possible to ensure that the generator outputs a voltage provided for one mode when and only when a designated electrode is connected to the generator.

[0025] Furthermore, due to the variable switches provided in the instrument being controlled by the generator, the concept according to the invention allows an automatic mode progression to be performed, during which different modes are subsequently used according to a provided program. For example, in a sealing and cutting instrument, it can be ensured that vessel or tissue sealing is started first and only thereafter dissection (tissue cutting) is performed. In this case, it is sufficient if the activation device outputs a simple on / off signal as the generator control signal. The mode progression can then be controlled by the generator itself, which also takes over the control of the variable switches of the instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further details of advantageous embodiments of the invention are the subject matter of the claims as well as the drawings and the associated description. The drawings show:

[0027] Figure 1 is an exemplary illustration of an instrument and associated generator in the form of a schematic overview diagram,

[0028] Figure 2 is a therapeutic device according to the invention having a generator and an apparatus in the form of a block diagram,

[0029] Figure 3 is an apparatus which is a part of a therapeutic apparatus according to the invention in the form of a block diagram,

[0030] Figure 4 is used according to Figure 3 Electronic switches in instruments,

[0031] Figure 5 is the signal carrier as a time diagram,

[0032] Figure 6 is a variable switch control signal in the time course as a schematic diagram,

[0033] Figure 7 is the high frequency voltage output by the generator as a schematic diagram, and

[0034] Figure 8 In the form of a diagram, Figure 5 The duty cycle of the signal carrier is used to obtain a variable switching control signal. DETAILED DESCRIPTION

[0035] Figure 1 1 shows a therapeutic device 101, which comprises an instrument 11 and a device 12 to which the instrument 11 is connected by means of a cable 13. As an example, the instrument 11 is Figure 1 1 is shown as a laparoscopic instrument. For this purpose, it comprises a handle 14 provided on a housing 15, from which a handle 16 extends in the distal direction, at the end of which a forceps-like tool 17 is held. The tool 17 is used for tissue coagulation and tissue cutting, i.e., for example, for sealing vessels (e.g., blood vessels) and for cutting vessels.

[0036] The tool 17 comprises coagulation electrodes 20, 21 at its jaws 18, 19, between which tissue can be grasped and clamped in a compressed manner. Due to the flow of current between the coagulation electrodes 20, 21, the tissue is heated and coagulated. For example, blood vessels and other hollow structures can thereby be fused and thus sealed.

[0037] At least one of the jaws 18, 19 is also equipped with a cutting electrode 22. The cutting electrode is used to cut through tissue. It is usually operated at a higher voltage and at a higher local current density than the coagulation electrode.

[0038] The instrument 11 is indicated in this form only for exemplary purposes. It can also be configured as an instrument for open surgical use or endoscopic use. Instead of the coagulation electrodes 20, 21 and the cutting electrode 22, electrodes for other therapeutic purposes can also be provided, such as ablation electrodes or the like, which can be activated at different points in time and for this purpose are connected to the generator by means of a switching device.

[0039] In order to open and close the jaws 18, 19, at least one operating element 23, for example in the form of a hand lever, is arranged on the housing 14. In addition, an activation device 24 with one or more switches or buttons 25, 26 can be provided for activating the electrodes 20, 21, 22 (see Figure 2 ). The activation device 24 may be a part of the apparatus 11, such as Figure 1 Alternatively, the activation device 24 can also be arranged in a separate housing and can be configured as a manual or foot switch, for example.

[0040] Furthermore, the device 12 may have an operating unit 27, by means of which the operation of the instrument 11 can be influenced. The operating unit 27 may be configured to set operating parameters for the treatment modes coag, cut or to perform other adjustments.

[0041] Figure 2 1 and 2. The treatment device 10 is illustrated separately and in an abstract manner. The device 12 includes a generator 28, which is configured to output a high-frequency voltage U suitable for performing different treatments on biological tissues. The voltage U is preferably a high-frequency voltage, and its peak value can vary in a range of approximately 100V to multiples of 100V or even larger. In addition, the generator 28 is preferably configured to modulate the high-frequency voltage. For example, the voltage U can be output as a continuous voltage or can also be output as an on / off switching voltage, wherein the pulse / pause ratio can be variable according to the desired treatment mode. For example, the generator 28 can be configured to output a voltage Ucoag for a first treatment mode coag (e.g., a coagulation mode), wherein the voltage should be effective between the two electrodes 20, 21. In addition, the generator 28 can be configured to output a voltage Ucut for a second treatment mode cut (e.g., a cutting mode), which is sufficient for tissue cutting and should be effective between the electrodes 22, 21.

[0042] The control of the generator is performed in dependence on the generator control signal sg. A control device 29 may be provided which is configured to evaluate the generator control signal sg and use it for controlling the generator 28. The control device 29 may be part of the apparatus 12 and may also be connected to the operating unit 27.

[0043] The cable 13 includes at least three lines NE, AE and AK leading to the instrument 11. When the line AE provides a neutral potential, the generator 28 outputs a therapy voltage and a therapy current to the instrument 11 via the line NE.

[0044] The instrument 11 comprises an electrically variable switch 30, by means of which the therapy voltage and the corresponding therapy current from the line NE are selectively directed to the electrode 20 provided for coagulation or to the electrode 22 provided for cutting. The variable switch 30 is a switching device which is switched by the control device 29 as part of the generator 28 by means of a variable switch control signal sw. The variable switch control signal sw is transmitted via the line AK. Similarly, the generator control signal sg is transmitted via the line AK. For this purpose, reference is made to Figure 3 :

[0045] The variable switch includes Figure 4 The two electronic switches 31, 32 are configured as an example. Figure 4 For this purpose, a switch 31 is shown by way of example, which has two field effect transistors T1, T2 oriented with opposite polarity and switched in series, the gate electrodes of which can be controlled in a potential-free manner via an optocoupler 33. The optocoupler 33 receives at its input a signal from the activation device 24 ( Figure 3 ) The signal a provided by the switch 31 can be connected to the electrode 22 via the coupling capacitor C1. Similarly, the second switch 32 can be connected to the electrode 22 via the coupling capacitor C2.

[0046] As an option, a third switch 34 that connects the capacitor side output of the switch 31 to the neutral line AE when receiving the control signal b can be additionally included as part of the variable switch 30. This switch 34 can be used to make the electrode 20 without voltage, while the electrode 22 for cutting is applied with current. In this case, the two electrodes 20, 21 together form a neutral electrode for the cutting voltage derived from the cutting electrode 22.

[0047] An electrical switch 25, 26, for example in the form of a button, is provided in or on the activation device 24 for switching on and off the generator 28. Figure 3 It is clear that these switches 25, 26 are switched in series with resistors R1, R2 located between the neutral potential on line AE and line AK. Line AK conducts the signal carrier. In order to activate the communication of the device 24 with the control device 29 and the communication of the control device 29 with the variable switch 30, the generator control signal sg and the variable switch control signal sw can be applied to the signal carrier.

[0048] The resistors R1 and R2 can have different values ​​in order to influence the signal carrier on the line AK in different ways to generate the generator control signal sg. For example, the signal carrier on the line AK is a square wave alternating current symmetrical to zero, having a frequency of, for example, 2 kHz, at which it alternates between two current values ​​of +25 mA and -25 mA. Depending on the value of the resistor R1 or R2 activated by actuating the switch 25 or 26, the control device 29 detects the resulting voltage as the generator control signal sg. Therefore, it activates the generator 28 in the first operating mode or in the second operating mode (i.e., for example, in the coagulation mode coag or in the cutting mode cut), whereupon the generator 28 outputs the desired voltage Ucoag or Ucut.

[0049] The signal carrier on line AK can also be a voltage signal with a defined frequency (e.g. 2 kHz) alternating between positive and negative voltage values. The control device 29 then detects the resulting current as the generator control signal sg and accordingly causes the generator 28 to operate in the signaled operating type.

[0050] The control device 29 is also configured to generate a variable switch control signal sw for controlling the variable switch 30 and output it via the line AK after detecting the generator control signal sg. The variable switch control signal sw is detected in the instrument 11 by a detector device 35, which can be configured as an average value detector 36 ( Figure 3 ).

[0051] The control device 29 is configured to encode the variable switch control signal sw in the duty cycle of the signal carrier. Figure 5 The duty cycle here means Figure 5 The ratio of the duration of positive voltage or positive current to the duration of negative voltage or negative current within a wave train illustrated in . Figure 5 The duty cycle characterized by the term "cut" is small in the left part of the diagram, while the duty cycle characterized by the term "coag" is high during the right phase. Used to detect these ratios is an average value detector 36, which can be configured, for example, in the form of an RC low-pass. The output of the low-pass can be connected to a light-emitting diode (e.g., of an optocoupler), thereby forming the input of the corresponding electronic switch 31, 32 (and 34 if appropriate). These light-emitting diodes are Figure 3 However, they can also be arranged in switches 31, 32, 34, such as from Figure 4Furthermore, between the light emitting diodes or other inputs of the switches 30, 32, 34 and the average value detector 36, switching or amplifying components can be arranged, which preferably have high-ohmic inputs which put little or no stress on the average value detector 36 and thus on the voltage on the capacitor C.

[0052] The treatment apparatus 10 described thus far operates as follows:

[0053] After startup, the instrument 11 is connected to the device 12, such as Figure 1 and 2 . If now, for example, biological tissue, such as a vessel or another vessel, is to be sealed and cut through, it is clamped by the jaws 18, 19, which are closed and compress the tissue by means of the operating device 23. By means of the activation device 24, in particular for example the activation of the switch 25, the generator 28 is now activated. This is performed by closing the switch 25, whereby a current flows through the resistor R1 and through the line AK. This is detected by the control device 29 as a generator control signal sg.

[0054] The generator control device 29 interprets the generator control signal sg as a command for adopting the coagulation mode and Figure 5 The modulation shown on the right side of the figure is applied to the signal carrier on line AK. The duty cycle is high, so that after low-pass filtering, according to Figure 6 On the right side of the figure, the positive variable switch control signal sw is detected by the average value detector 26 and provided as the control signal a to the switch 31. When the switch 31 is closed, the variable switch 30 connects the electrode 20 to the line NE and thus to the high frequency generating part of the generator 28. The other switches 32 and 34 remain open (non-conductive). In doing so, the coagulation voltage Ucoag is applied to the electrode 20, whereby the coagulation current can flow from the electrode 20 to the electrode 21.

[0055] If it should be changed to cutting mode, the user operates another switch 26. Now, the second resistor R2 switches between the neutral potential of line AE and the signal carrier on line AK. This is interpreted by the control device 29 as a generator control signal sg for cutting mode. It therefore changes according to Figure 5 The left side in FIG. 1 changes the modulation of the signal carrier (line AK).

[0056] Depending on the generator control signal sg, the generator voltage U now has a different value Ucut (left) compared to the coagulation mode Ucoag (right), as shown Figure 7The average value of the signal carrier is now negative, which is why the detector 35 opens the switch 31 and closes the switches 32, 34. If this has occurred, the high-frequency voltage U is now applied to the output 22 as a cutting voltage Ucut with a correspondingly higher amplitude, as shown in FIG. Figure 7 When the switch 34 is closed, the cutting voltage Ucut is directed to the electrode 22 via the variable switch 30. Thus, the two electrodes 20, 21 are connected in parallel and together form the neutral electrode of the cutting electrode 22.

[0057] As from Figure 8 It is clear that the switching of the variable switches and the opening and closing of the high voltage part of the generator 28 are performed with a time offset. The closing of the switches 31, 32, 34 is always performed before the activation of the high voltage part of the generator 28. Vice versa, the generator 28 is always closed before the corresponding switch of the variable switch 30 is opened. This is based on Figure 6 and 7 The temporal sequence of the generator control signal sg and the variable switch control signal sw shown in the figure is clear.

[0058] The described switching process can be performed sequentially once or multiple times, or in rapid sequence, to achieve, for example, virtual simultaneous cutting and coagulation. During the first operating mode (e.g., coagulation) and during the second operating mode (e.g., cutting), it is possible to accurately monitor the current and voltage of the generator or the power output by the generator or the tissue condition, and control the generator accordingly. In addition, the current and voltage are individually adjustable for each operating mode (coag, cut) on the device 12.

[0059] In addition to the manual switching between the different operating modes described above, it is also possible to store and retrieve different treatment schedules in the generator 28. In this case, after a start signal has been output from the activation device 24, the generator 28 controls the variable switch 30 according to the predefined treatment schedule and outputs the corresponding voltage and current to the respectively activated electrode 20 or 22 according to the variable switch position.

[0060] The therapeutic device 10 according to the invention comprises an instrument 11 connected to a power supply device 12. The instrument 11 and the device 12 can control each other. With the aid of an activation device 24 provided on the instrument 11 or otherwise provided, the generator can be activated in a first or second operating type. The instrument 11 comprises a variable switch 30 to direct the power provided by the generator to the first or second electrode pair 20 / 21 or 22 / 21. The variable switch 30 is controlled by the generator 12. This provides the possibility of storing treatment schedules in the generator and executing them with the instrument 11 without the user having to change the operating type.

[0061] List of reference symbols:

[0062] 10 Treatment Equipment

[0063] 11 Instruments

[0064] 12 Installation

[0065] 13 Cables

[0066] 14 handles

[0067] 15 Shell

[0068] 16 handles

[0069] 17 Tools

[0070] 18 Upper jaw

[0071] 19 Lower jaw

[0072] 20 Upper electrode

[0073] 21 Lower electrode

[0074] 22 Cutting Electrode

[0075] 23Operation equipment

[0076] 24Activate the device

[0077] 25, 26 switch

[0078] 27 operation units

[0079] 28 Generator

[0080] 29 Control Equipment

[0081] NE Line for treatment current and treatment voltage AE Line for neutral potential AK Line for signal carrier 30 Variable switch

[0082] sw variable switch control signal sg generator control signal 31, 32 electronic switch

[0083] 33 Optocoupler

[0084] a, b control signal

[0085] C1, C2 coupling capacitor 34 electronic switch

[0086] 35 detector equipment

[0087] 36 Average value detector

[0088] R resistor

[0089] C Capacitor

[0090] U Voltage

[0091] Ucoag coagulation voltage

[0092] Ucut cutting voltage

Claims

1. A therapeutic device (10), in particular for coagulation and cutting of biological tissue of a human or animal patient, A generator (28) is provided, the generator (28) being configured to output a voltage (U) having a first value (Ucoag) for a first treatment mode (coag) and, alternatively, having a second value (Ucut) for a second treatment mode (cut) according to a generator control signal (sg), and to output a variable switch control signal (sw) corresponding thereto in a first condition or a second condition different from the first condition, There is an apparatus (11) comprising two electrodes (20, 22) connected to a generator (28) via an electric line (NE), An electrically variable switch (30) is arranged between the electrodes (20, 22) and the line (NE), which connects one or the other of the electrodes (20, 22) to the line (NE) according to a variable switch control signal (sw), and An activation device (24) is provided, the activation device (24) being configured to generate a generator control signal (sg).

2. The therapeutic device according to claim 1, characterized in that The generator (28) is a high frequency generator configured to output a voltage having a frequency between 100 kHz and 5 MHz.

3. The therapeutic device according to any one of the preceding claims, characterized in that The first treatment mode (coag) is the mode used for tissue coagulation.

4. The therapeutic device according to any one of the preceding claims, characterized in that The second mode (cut) is a mode for tissue cutting.

5. The therapeutic device according to any one of the preceding claims, characterized in that The first value (Ucoag) of the voltage (U) is the peak-to-peak voltage measured from the positive peak to the negative peak, the second value (Ucut) of the voltage (U) is the peak-to-peak voltage measured from the positive peak to the negative peak, and the first value (Ucoag) of the voltage (U) is less than the second value (Ucut).

6. The therapeutic device according to any one of the preceding claims, characterized in that The generator (28) comprises a control device (29) configured to send a signal carrier wave to the activation device (24) via a line (AK).

7. The therapeutic device according to claim 6, characterized in that The activation device (24) is configured to generate a generator control signal (sg) from a signal carrier in accordance with a user input.

8. The therapeutic device according to any one of the preceding claims, characterized in that The activation device (24) comprises at least two switches (25, 26) connected to different resistors (R1, R2).

9. The therapeutic device according to any one of the preceding claims, characterized in that An activation device (24) is arranged in the apparatus (11).

10. The therapeutic device according to claim 6, characterized in that The signal carrier includes a variable switch control signal (sw).

11. The therapeutic device according to claim 6, characterized in that The signal carrier is an AC signal with a variable duty cycle.

12. The therapeutic device according to claim 6, characterized in that The variable switch control signal (sw) is defined by the duty cycle of the signal carrier.

13. The therapeutic device according to any one of the preceding claims, characterized in that A mean value detector (36) is provided to extract the variable switch control signal (sw).

14. The therapeutic device according to any of the preceding claims, characterized in that The generator control signal (sg) is defined to start temporally after the variable switch control signal (sw) and end temporally before the variable switch control signal (sw).

15. A method for controlling a therapeutic device (10) according to claim 1, wherein: providing a signal carrier output from the generator (28) to the activation device (24), generating a generator control signal (sg) corresponding to the desired treatment mode (coag, cut) from the signal carrier by means of the activation device (24) and supplying it to the generator (28), The generator (28) then varies the signal carrier to generate a variable switch control signal (sw), In the apparatus (11), a variable switch control signal (sw) is determined from the signal carrier and provided to the variable switch (30), The variable switch (30) then connects the electrodes (20, 22) suitable for the desired treatment mode (coag, cut) to the line (NE), The voltages (Ucoag, Ucut) for the desired treatment mode (coag, cut) are then generated by means of a generator (28) and supplied to the electrodes (20, 22).

Images