Electrosurgical device

The invention relates to an electrosurgical device according to the preamble of claim 1.

Such an electrosurgical device is known from the document DE 24 29 021 A.

A device of the type mentioned at the outset is used in the so-called electrosurgery. High-frequency currents generated by the HF generator are conducted into the body of a patient via the HF instrument connected to the HF generator, especially in the context of minimally invasive surgery, in order to coagulate tissue at an operation site with the HF instrument under the effect of the high-frequency currents And / or cut. When coagulated, vessels are deserted to bring about blood stagnation in the separation of tissue. Coagulation and cutting by means of high-frequency current differ with regard to the applied power of the high-frequency current and, if applicable, with regard to the duration of the application. In the coagulation mode of an electrosurgical device, as a rule, the RF power is intermittent and intermittent, whereas high frequency power is required to cut tissue by means of high-frequency current in order to generate the arc required for cutting tissue by means of high-frequency current. Furthermore, cutting is not intermittent, but continuous.

According to these two previously described modes of coagulation and cutting, the HF generator of such an electrosurgical device is capable of providing high frequency currents with the corresponding power required for coagulation and cutting.

However, when working with an HF instrument, the "coagulation" and "cutting" modes are usually not required simultaneously, but alternately, ie the working steps of cutting and coagulation take place successively and alternately, but not at the same time. The HF generator can be activated accordingly with the "coagulate" and "cutting" modes.

In order that the surgeon operating the HF instrument does not have to activate the operating modes on the side of the operating table and in the non-sterile area of ​​the operating room, or has to instruct an assistant to switch between the operating modes, An activation possibility of the operating modes is provided in the form of two switches which can be operated with the fingers.

The first switch is assigned, for example, the "coagulate" mode and the second switch the "cutting" mode. The first switch and the second switch thus respectively correspond to a first operating state, for example a higher output power of the HF generator, or a second operating state, for example a lower output power with a possibly intermittent operation.

The first switch and the second switch are connected to at least one control signal line which is connected to the main line of the HF instrument via which the active electrode is fed at the distal end of the HF instrument. A control input signal is fed via the main line in addition to the high-frequency current, from which, according to which of the two switches is actuated, a corresponding control output signal is generated by means of the signal coding means for activating the operating state assigned to the actuated switch, via which control signal line, Is connected to the RF generator in order to activate the corresponding operating state of the HF generator.

The electrosurgical device known from the aforementioned document DE 24 29 021 A has an HF instrument which has three switches. When the first switch is closed, a half-wave of the alternating current flows to excite a first relay. When the second switch is closed, the other half-wave of the alternating current flows to excite a second relay. When the third switch is closed, the main line is directly short-circuited with the signal line so that both half-waves of the alternating current can flow.

In a device known from DE 30 45 996 A1, further switches are provided on the HF instrument, in addition to the aforementioned two switches for switching between the "coagulating" and "cutting" modes, namely for respectively increasing or decreasing the output power in FIG Of the selected operating mode. In this known device, additional signal lines are required in order to realize the further functions for switching the HF generator.

A device comparable to this is known from EP 0 186 369 A1, which also has four switches for switching between the "coagulating" and "cutting" modes, as well as for increasing or decreasing the output power in each of the two operating modes. In this known device, a total of three signal lines are required for the four switches.

The invention is therefore based on the object of further developing an electrosurgical device of the type mentioned in the introduction in such a way that an activation possibility of the first, second and at least a third operating state of the HF generator from the HF instrument is provided with the least possible constructional effort.

According to the invention, this object is achieved with regard to the electrosurgical device mentioned at the beginning in that the signal coding means assigned to the first and second switches are also assigned to the third switch.

Instead of providing additional control signal lines in the HF instrument in the case of more than two provided switches, in the case of the device according to the invention, the design complexity in the realization of the switching to a third operating mode of the HF generator is advantageously kept low by the fact that the third switch, For example common, control signal line, whereby additional control signal lines are saved. The signal coding means for generating the control output signals are preferably designed in such a way that upon actuation of the third switch from the control input signal, which is preferably the same for all three switches, an additional control output signal is produced which differs from the control output signals for activating the first and second operating states , In order to activate the third operating state of the HF generator.

This further control output signal is fed to the HF generator via the common control signal line.

According to the invention, the signal coding means assigned to the first and second switches are also assigned to the third switch.

This measure has the advantage that not only the already existing control signal lines are used for the at least third switching function, so that no additional control signal line is required, but also the already existing signal coding means is used and no additional signal coding means is required Is further reduced.

In a preferred embodiment, the third switch is connected to the first switch and the second switch such that its closed state corresponds to a simultaneous closed state of the first and second switch.

This measure leads to a particularly simple integration of the third switch into the system of the first and second switches, with the further advantage that the same as the signal coding means for generating the control output signals, the same signal coding means can be used as for a device with only two switches as described above . However, instead of having to operate the first switch and the second switch together, this measure has the further advantage of simple operation, since only one switch, namely the third one, must be actuated to establish this switching state.

In a further preferred embodiment, the third switch is electrically connected in parallel to the first and second switch, which can be realized simply by a few additional lines and thus can be constructed in a simple manner.

Alternatively, in a second embodiment, it is also preferred if the third switch is mechanically coupled to the first and second switches such that, upon actuation of the third switch, the first and second switches are simultaneously closed.

This measure has the advantage that the switching effort against the system with two switches by the third switch is not increased at all because the third switch is merely mechanically coupled to the first and the second switch. The mechanical coupling of the third switch with the first and second switch must, of course, satisfy the condition that the first and the second switch must be actuatable independently of one another despite the mechanical coupling with the third switch in order to also, in addition to the third operating state, also the first and second operating states Of the RF generator can be activated independently of one another.

In a particularly preferred embodiment, the signal coding means has a first diode which is assigned to the first switch and a second diode which is assigned to the second switch, the first and second diode being connected to the control signal line in the opposite polarity.

This configuration of the signal coding means, which is already known in devices with a possibility of switching between two operating modes, is particularly advantageous in the context of the present invention because these two diodes connected opposite to one another and connected in parallel are sufficient to activate the third operating mode via the third switch The current flow through both diodes is simultaneously released by actuating the third switch. While the first diode, for example, passes through the positive half-wave of the input signal and thus activates the first operating state, the second diode passes the negative half-wave when the second switch is actuated to activate the second operating state, the full input signal is restored when the third switch is actuated Is fed to the RF generator to activate the third operating state. A special signal detection is not necessary for the HF generator.

Further features and advantages will become apparent from the following description and from the attached drawing.

It is to be understood that the features mentioned above and those which are still to be explained below can be used not only in the particular combination indicated but also in other combinations or in a single setting without departing from the scope of the present invention.

An exemplary embodiment of the invention is shown in the drawing and will be described in more detail with reference to the following. Show it:<dl id="dl0001"><dt>FIG</dt><dd>4 is a schematic overall illustration of an electrosurgical device which allows three operating modes;</dd><dt>FIG</dt><dd>A circuit diagram of a known device with two switches for switching between two operating modes;</dd><dt>FIG</dt><dd>2 is a circuit diagram of the device in FIG. 1, in which, according to the present invention, the device in FIG. 2 has been extended with two switches to three switches; and</dd></dl>

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows an electrosurgical device provided with the general reference numeral 10. The device 10 is used in the context of HF surgery.

The device 10 has an HF generator 12 which generates high-frequency currents or voltages of several hundred kHz. The RF generator 12 is capable of generating high frequency currents with an output power suitable for coagulating tissue, as well as high frequency currents with an output power suitable for cutting tissue.

The device 10 also has an HF instrument 14 with which the high-frequency currents generated by the HF generator 12 in the human or animal body can be applied to the tissue to be treated.

The HF instrument 14 has a handpiece 16 at its proximal end, as well as a shaft 18 connected to the handpiece 16, which is long-stretched and small in diameter, so that it is suitable for minimally invasive surgery.

An electrode 20 is arranged at the distal end of the shaft 18, which electrode can be acted upon by the high-frequency current of the HF generator 12 as an active electrode. For this purpose, the HF generator 12 is connected to the handpiece 16 of the HF instrument 14 via a corresponding cable 22, and the high-frequency current of the HF generator through the handpiece 16 and through the shaft 18 to the active power supply is supplied via a corresponding current supply, not shown Electrode 20.

A neutral electrode 24 is also connected to the HF generator 12 via a line 26, the neutral electrode 24 usually being connected to the body surface of the patient in order to close the HF circuit over the body surface of the patient. The arrangement shown in FIG. 1 is accordingly a monopolar HF arrangement, but the present invention is not limited to such a monopolar application, but is also suitable for bipolar applications. In the case of bipolar applications, the neutral electrode is arranged in the immediate vicinity of the active electrode 20 on the HF instrument itself.

A first switch 28 in the form of a first button 28, a second switch 30 in the form of a second button, and a third switch 32 in the form of a third button are arranged on the handpiece 16.

The three switches 28, 30 and 32 serve to activate a certain operating state of the HF generator when they are actuated selectively.

1, an operating state of the HF generator 12, which corresponds to the "coagulate" mode, ie the HF generator 12 generates a high-frequency current, is activated when the first switch 28 is actuated. In the exemplary embodiment shown in FIG Lower output power and, if necessary, intermittently interrupted. When the second switch 30 is actuated, a second operating state of the HF generator 12 which corresponds to the "cutting" mode is activated, ie, in this operating state, the HF generator generates a high-frequency current with an output power higher than the first operating state and without a time interruption. When the third switch 32 is actuated, a third operating state of the HF generator 12 is activated which corresponds to a third operating mode "rapid, alternating activation of the cutting and coagulation current", ie, in this operating state, the HF generator alternately generates high-frequency currents, Are suitable for cutting.

The switches 28, 30 and 32 are preferably designed in the form of keys, ie an activation of the corresponding operating state is effected as long as the corresponding key is held down.

With reference to FIGS. 2 and 3, the activation of the operating states of the HF generator 12 will now be described in more detail with reference to two circuit diagrams.

FIG. 2 shows a circuit diagram of an HF instrument known from the prior art, which has only two switches 28 'and 30', in order to switch between the "coagulating" and "cutting" modes. Components comparable to the HF instrument 14 in FIG. 1 are provided with the same reference symbols, supplemented by a raised line. Electrode 20 'is connected to the RF generator via a main lead 34' extending through the shank and handpiece of the RF instrument.

Branches 36 'and 38' extend from the main line 34 ', via which the switches 28' and 30 'are connected to the main line 34'.

Signal coding means 40 'are assigned to the switches 28' and 30 '.

The switches 28 'and 30' are also connected via the branch lines 36 'and 38' to a control signal line 42 'common in the preferred embodiment shown, which in turn is connected to the HF generator 12'.

In addition to the high-frequency current with which the electrode 20 'is acted upon, a control input signal is fed via the main line 34' from which the signal coding means 40 'produce a corresponding control signal as a function of the switching state of the first switch 28' and of the second switch 30 ' Which is fed back into the HF generator 12 'via the control signal line 42' in order to activate the operating state which is assigned to the corresponding switch 28 'or 30'.

The signal coding means 40 'comprise a first diode 44' and a second diode 46 'which are connected to one another in the opposite direction to the control signal line 42'.

The mode of operation of the circuit shown in FIG. 2 will now be described in more detail. A preferably low-frequency alternating current is fed into the main line 34 'as a control input signal in addition to the high-frequency alternating current, with which the electrode 20' is applied.

If the first switch 28 'is then actuated, ie, closed, the circuit for this additionally fed alternating current is closed via the branch line 36', the first switch 28 ', the first diode 44' and the control signal line 42 '. The first diode 44 'leaves only the positive half-wave of the alternating current. The positive half-wave of the additionally supplied alternating current now serves as a control output signal which is fed via the control signal line 42 'to the HF generator 12 in order to activate the first operating state, ie to activate the "coagulate" mode.

If, instead of the first switch 28 ', the second switch 30' is actuated, ie closed, the circuit for the additionally fed alternating current is closed via the branch line 38 ', the second switch 30', the second diode 46 'and the common control signal line 42'. The second diode 46 'transmits only the negative half-wave of the additionally fed alternating current, in the opposite direction to the diode 44', this negative half-wave now being fed to the HF generator 12 'as a control output signal via the common control signal line 42', as a result of which the second operating state of the HF generator 12 ' Generator 14 'is activated. This activates the "cutting" mode.

FIG. 3 shows the corresponding circuit diagram for the device according to the invention in FIG. 1, in which all switching elements from FIG. 2 are reproduced, as a result of which the structural simplicity of the present invention becomes clear.

Without requiring a further control signal line, the third switch 32 is also connected to the control signal line 42. The signal coding means 40 are designed in such a way that when the third switch 32 is actuated, ie, when the third switch 32 is closed, a further control output signal is generated for activating the third operating state of the HF generator 12, this control output signal being generated by means of the control signals generated with the switches 28 And 30 common control signal line 42 is fed to the HF generator 12.

In the exemplary embodiment shown, this is realized by the fact that the third switch 32 is connected to the first switch 28 and the second switch 30 in such a way that its closed state corresponds to a simultaneous closed state of the first switch 28 and the second switch 30. For this purpose, the third switch 32 is connected, on the one hand, to the main line 34 via two further branch lines 48 and 50 and, on the other hand, to the branch lines 36 and 38 of the first switch 28 and of the second switch 30, respectively.

When the third switch 32 is closed, the circuit is now closed via the first diode 44 as well as via the second diode 46, whereby the alternating current, which is additionally fed into the main line 34, is supplied unchanged via the common signal line 42 to the HF generator 12, The third operating state of the HF generator 12 is activated, which in the present exemplary embodiment consists in switching alternately between the "coagulating" and "cutting" modes. Therefore, neither an additional control signal line nor an additional control input signal fed into the main line 34 is required for the third switch 32, and thus for the third operating state, nor is an additional signal detection required in the HF generator 12. The rapid alternating activation of the cutting and coagulation current during the actuation of the third switch 32 takes place with the frequency of the alternating current fed in as a control input signal when the third switch 32 is closed and accordingly the positive and negative half waves of the additionally fed alternating current via the control signal line 42 Is fed back to the HF generator 12.

The frequency of the fed alternating current can advantageously be preset at the HF generator.

3, the third switch 32 is connected in parallel with the first switch 28 and parallel to the second switch 30.

Instead of an electrical parallel circuit of the third switch 32 with the switches 28 and 30, the same effect can be achieved within the scope of the present invention by the fact that the third switch 32 is mechanically coupled to the first and second switches 28 and 30 such that, Actuation of the third switch 32, the first and second switches 28 and 30 can be simultaneously closed. The mechanical coupling, however, must be configured in such a way that the first switch 28 and the second switch 30 can also be actuated independently of one another in order to be able to selectively activate the first operating state and the second operating state.