FR2558368A1 - ELECTROSURGICAL UNIT - Google Patents

Abstract

SURGICAL UNIT FOR USE IN SURGICAL DIATHERMIA, INCLUDING A MICROCOMPUTER 1 TO CONTROL THE OUTPUT OF THE UNIT. THE MICRO-COMPUTER IS CONNECTED AS: AA BE ADDRESSED BY ONE OR MORE SIGNALS COMING FROM A USER INTERFACE 3A TO 3J, 4A, 4B, 5A TO 5C FOR SELECTION OF A DESIRED OUTPUT OF THE ELECTROSURGICAL UNIT, AND MEANS 13 SERVING TO SAMPLE, IN ONE OR MORE LOCATIONS, THE ELECTRICAL STATE OF THE ELECTROSURGICAL UNIT, AND BA PROVIDING ONE OR MORE CONTROL SIGNALS TO AN ENERGY GENERATOR CIRCUIT 9, 10, 7M, 7B, 11 SERVING TO PRODUCE OUTPUT ENERGY FROM THE ELECTROSURGICAL UNIT AND TO ONE OR MORE DEVICES 14A TO 14C, 15A TO 15H, 16A TO 16C, 18 SERVING TO TRANSMIT TO THE USER INFORMATION REGARDING THE STATUS OF THE ELECTROSURGICAL UNIT .

Description

The invention relates to an electrochemical unit

  gical for use in surgical diathermy.

  Surgical diathermy is a process by which heat is used to cut tissue and coagulate blood. This heat is generated by the passage of a high frequency electric current which, in unipolar electrosurgery, passes through the body of the patient from the place of cutting or coagulation. This high frequency current, which is typically of the order of 500 kHz to 1 MHz with a power output of several hundred watts, is provided by an electrosurgical unit. The surgical effect obtained, ie cutting or coagulation, is

  determined by the waveform of the output current used.

  In unipolar electrosurgery, the electrosurgical unit is connected to both an "active" electrode and a "plate" electrode. The active electrode has a very small surface area and is used for cutting and / or coagulating blood. The plate electrode, which is usually attached to the thigh of the patient, has a much larger surface area and reduces the active current

to the electrosurgical unit.

  Given the high power levels used in electrosurgery, the patient may experience severe burns if the plate electrode is not in good electrical contact with the skin or if the electrical connection between the electrode and the unit

  electrosurgical is mediocre or broken.

  Thus, it is extremely important that the circuit formed by these two electrodes and in particular, that the plate electrode is constantly monitored and Reliable and that the electrosurgical unit is provided with

  safety circuit breaker responding to this monitoring.

  Circuits that monitor the connection between the plauque electrode and the electrosurgical unit are known and widely used, as well as those that monitor contact between the patient and the plate electrode. For this purpose, these circuits generally monitor the current flow and / or the voltage on the electrode

in plate.

  In addition, the electrosurgical unit must in itself be as fault-proof as possible, ensuring automatic cuts if

  any electrical or electronic fault occurs.

  For this purpose, the unit must be self-controlled.

  Until now, these command functions

  and monitoring available in electrosurgical units

  wedges are provided by electrical / electronic circuits using valves, relays, transistors and circuits

  integrated solid, together with separate components.

  The formed units are complex and expensive to manufacture and do not easily adapt to the increasing demand

security and flexibility.

  In addition, the electrical output of electrosurgical units currently available

  is limited both in form and level.

  The operating voltage waveforms that are used today have been chosen on the basis of a crude and subjective observation of this limited range of waveform choices. However, it is believed that the optimal level and optimal waveform composition may vary not only from one operation to another, but also during an individual process of cutting or coagulation. Thus, a unit capable of producing a wide variety of output waveforms is desired

  for the study and possible adoption of advanced techniques

  surgical diathermy.

  An object of the invention is to provide an electrochemical unit which is economical to manufacture and which at the same time allows more flexible functions of safety and control control and the provision of

various outlets.

  Accordingly, the invention provides an electrosurgical unit for use in surgical diathermy, the unit comprising a microcomputer for controlling the output of the unit, the microcomputer being connected so as to: a) be addressed by one or more signals from a user interface for selecting a

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  desired output of the electrosurgical unit, and means for sampling, in one or more

  locations, the electrical state of the electrochemical unit

  and (b) supplying one or more command signals to an energy generating circuit for generating the output energy of the electrosurgical unit and to one or more devices for transmitting to the user information about the state of

the electrosurgical unit.

  In a preferred embodiment, the electrosurgical unit is designed to generate both unipolar and bipolar outputs.

  for selection by the user.

  In an embodiment where the electrosurgical unit has a unipolar output, a safety circuit is provided for monitoring a plate electrode circuit, the microcomputer being connected to this circuit and addressable by

signals from it.

  Preferably, the safety circuit monitors the connection between a plate electrode and the electrosurgical unit, the voltage of the plate electrode relative to the earth and the electrical contact.

  between this electrode and the patient's body.

  The waveform of the output of the electrosurgical unit is preferably generated by the microcomputer. The microcomputer may be designed to be connected to an external computer, for example by a telephone line. This allows the external computer to acquire operating data stored in the microcomputer and also to reprogram this microcomputer. Operating data obtained in this way from a large number of electrosurgical units can thus be collated and analyzed centrally. to obtain

  data concerning the optimum output of the electronic unit

  surgical danc different conditions. This data can then be used in reprogramming and thus updating the operation of these same

electrosurgical units.

  In a preferred embodiment of the invention, the microcomputer is directly programmable by the user, which makes it possible to choose the outputs that the unit can provide according to the user.

  and / or the surgical method to be used. This reprogramming

  Preferably, the microcomputer is replaced by a pluggable preprogrammed memory device.

  In another embodiment, the microorganism

  is programmed so that the electrochemical unit

  gique performs a self-test circuit test routine.

  diagnosis when switching on and / or when instructed to do so by activation of a manually operable switch. This facility provides significant benefits in terms of general unit security and localization

faults.

  Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIG. 1 shows a block diagram illustrating

  the operation of an electrochemical unit execution mode.

  in accordance with the invention, FIG. 2 is a block diagram illustrating a preferred embodiment of the invention, FIG. 3 is a block diagram illustrating an embodiment of a unipolar power control and amplification circuit and FIG. 4 is a block diagram illustrating a mode of execution of a bipolar amplification circuit

- power.

  In FIG. 1, the electrosurgical unit comprises a microcomputer 1 which can be addressed by

  instruction signals A coming from a user interface

  B signals generated by a safety monitoring circuit and C signals from other parts of the electrosurgical unit and indicating the state of these parts. The microcomputer processes the received signals and generates control signals D for controlling the type, shape and level of the output power of the electrosurgical unit and for connecting and disconnecting this output, and E signals for controlling visual displays. and audible devices that transmit to

  the user information on the status of the electronic unit

surgical.

  Fig. 2 shows an electrosurgical unit

  which is designed to provide both a unipolar output waveform and a bipolar output waveform, at a respective output. Unlike unipolar modes of "cutting" and "coagulation", bipolar electrosurgery

  does not use a large plate electrode.

  In this case, the diathermy current is formed between two branches of a clamp. It is used for the coagulation of blood vessels and has a particular application in delicate processes that require precise localized coagulation such as neurosurgery, plastic surgery and laparoscopic sterilization. Bipolar electrochicrurgy requires only low power outputs, of the order of 50 W, unlike the 400W generally used in unipolar electrosurgery and therefore, unlike unipolar electrosurgery, it does not represent in itself even no big

potential risk for the patient.

  In this embodiment, the microcomputer 1 comprises a pulse pattern generator 2, in addition to the devices such as a microprocessor, program and data memories, address decoders, a clock, excitation exciters, and so on. bus, a monitoring timer and other peripheral devices, which together constitute a microcomputer. The program memory contains the program instructions and

  data for the overall operation of the microproces-

  while the data memory temporarily stores status data of various parts of the electrosurgical unit. In this embodiment, the microcomputer is constituted by the

microchip family NSC 800.

  The pulse pattern generator 2 is a timer whose output is determined by the microprocessor in accordance with waveforms set in advance for unipolar and bipolar operation and stored in the program memory. The output of this generator 2 determines the waveform obtained at the respective outputs of the unit, as will be described in more detail below. In this embodiment, the

  generator 2 is made up of meter chips

timer.

  The microcomputer 1 is programmed to receive binary input signals at a bit of ten two-position switches 3a-3j for the selection of operating modes via appropriate interface devices such as, for example, Schmitt flip-flops. , potential dividers and low-pass filters. Of these, three finger switches are provided for the respective selection of one of the three main modes of operation, namely "cut", "coagulation" and "bipolar". Three foot-operated electrical contact switches reproduce the action of these finger switches and another pneumatically operated foot switch

  additional selection of bipolar operation.

  Three other two-position switches are provided on the electrosurgical unit. A switch

  3j lock allows the locking of the three

  Bipolar selectors 3c, 3d, and 39 so that an operator can use any of these

  switches or use them all during the same process.

  The 3h switch allows the selection of unipolar operation without specifying the "cut" mode or the "coagulation" mode and the switch 3j makes it possible to switch from unipolar operation to bipolar operation.

or vice versa.

  The microcomputer 1 also receives one-bit binary signals from two other switches 4a and 4b provided on the electrosurgical unit for

  the selection of certain secondary modes of operation.

  Switch 4a is a two-position switch that selects one of two voltage levels, high and low, for bipolar operation. The switch 4b is provided on the unit and has four positions for the selection of any one of four waveforms

  preprogrammed programs contained in the program memory.

  Again, these binary signals are provided to the microordinate

  1 through appropriate interface devices.

  The microcomputer 1 can also be addressed by an eight-bit binary coded signal coming from three digital power level adjustment switches Sa a 5c which are respectively provided for preselection by the user of the power level.

  of each of the three main modes of operation.

  As indicated above, the output waveform of the electrosurgical unit is controlled by means of the pulse pattern generator 2. On command of the microprocessor, this generator provides two two-line bit signals 19 of which one is connected to two power amplifiers 7m and 7b and the other to the power amplifier only 7m, to control the impulse configuration of the form

waveform of the output current.

  The unipolar or bipolar output selection is effected by means of a signal sent by the microprocessor on one of the two muting lines 8m and Bb respectively connected to a "unipolar" power controller 10 "amplifier" bipolar "7b. This signal inhibits the power supply to the output

  not selected by the user.

  To generate a unipolar output, the microcomputer 1 supplies an eight-bit signal, via a digital-to-analog converter 9, to set the output voltage of the high-power control member 10 which supplies the unipolar amplifier 4n. Control member 10 provides continuously variable power supply, at a fixed voltage Jictée by the voltage level signal provided by the microcomputer. In the present embodiment, this voltage can take any value between 0 and 150 V. The control member 10 is constituted by a switch mode regulator, such regulators are well known and in this embodiment, as shown in FIG. 3, it constitutes a MOS switching transistor with a high-voltage field effect (200 V), FET1, which charges a capacitor C1 via an inductor L1. A diode D2 maintains the flow of current through the inductor L1 for periods of time when the transistor FET1 does not conduct. A voltage feedback circuit, formed of a power control amplifier 22 and associated components including a switch mode controller 25, ensures that the voltage of

  output of the control member 10 follows the input of the ampli-

  This input is taken from the microprocessor via the analog-to-digital converter 9. The entire switch mode regulator is powered by a conventional source of power.

DC current 21.

  The voltage output of the controller is fed directly to the unipolar power amplifier 7m. As shown in FIG. 3, this circuit comprises two FET2 and FET3 high power field effect MOS transistors designed to operate in the symmetrical mode and connected at one end of each of the two parallel primary windings of an output transformer TM, the other ends being connected to the output of the power control member 10. The pulse pattern derived from the microcomputer interfaces with the gates of the MOS field effect transistor switches FET2, FET3 via buffer circuits suitable for high-speed forming a pulse generator circuit 24 of known type to provide fast switching with a rise time less than 100 ns. In the cut mode, this generator circuit supplies pulses of constant width and range in response to a signal from the pulse pattern generator

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  2 while in mixing and coagulation modes, this circuit provides a waveform that has a configuration

  pulse group generated by the generator 2.

  This combination of voltage control and pulse configuration enables any desired pulse configuration to be generated at any voltage level up to approximately

  3 kV peak-to-peak on the secondary winding of the transformer

TM.

  In order to protect the power generating circuit 24 against overloads and excessive current, the voltage on each transistor FET2 and FET3 is measured

  during the conduction period. This tension is transferred

  diode D5 and D6 to a current limit trip circuit 23. If the voltage at the input of circuit 23 exceeds a predetermined value, a signal is supplied to the pulse generator so as to cause an increase in the pulse interval to several hundred times its normal value. This ensures that excessive currents can not pass

by the transistors FET2 and FET3.

  The bipolar amplifier 7b is connected to a fixed voltage rail and the voltage level selection between "high" and "low" is effected by means of a one-bit signal supplied by the microprocessor via the line 11 connected to the 7bo bipolar amplifier Precise adjustment of the output power level of the bipolar amplifier 7b is achieved by means of pulse group modulation, as dictated by the microcomputer via of the output of the pulse configuration general 2, in response to the positioning of the bipolar power level control switch 5co as illustrated in FIG. 4, the power bipolar amplifier 7b comprises two medium power field effect FET4 and FET5 MOS transistor switches operating in the symmetrical mode and connected to an axis of each of two parallel primary windings of an output transformer T. The pulse pattern drawn from the microcomputer interfaces with the grids of the FET4, FET5 Field Effect MOS Transistor Switches by means of suitable high gain buffer circuits forming a pulse group generator to provide fast switching. with a rise time of less than 100 ns. The voltage level "high" / "low" is applied

  at the other ends of the primary windings of the

  TB meter. This combination of impulse configuration control and "high" / "low" voltage level enables any desired pulse configuration to be generated at either 400V peak-to-peak (high power) or 200V peak. -crest (low power) at the secondary drain of the transformer TB; the variation of the configuration

  impulses controlling the total power supplied.

  The output of the amplifiers 7m and 7b is supplied to the corresponding output of the unit via the respective transformer TM, TB and the isolation capacitors Cm, Cb. A safety circuit 12 is provided and

  monitors the plate electrode when the electrosurgical unit

  wedge is used in unipolar mode. In the event of a failure in the connection between the plate and the electrosurgical unit, a one-bit binary signal is sent to the microcomputer 1 which in turn sends signals to inhibit an output of the unipolar amplifier 7m and actuates signals of alarm. During the surgical procedure, the safety circuit monitors the voltage on the plate electrode relative to the earth, compares it to a voltage reference level, and if its value exceeds a safety margin, sends a one-bit signal to the microcomputer which acts to disconnect the amplifier 7m and / or the switch during alarm signals. The safety circuit also monitors patient isolation by measuring the impedance between the plate circuit and the ground. Again, if the detected impedance indicates the possibility of excessive conduction to earth through the patient, a one-bit signal is sent to the microcomputer to inhibit the power output.

  and activate alarm signals.

  We also monitor the conditions of 1 1

  operation of the electrosurgical unit itself.

  A one-bit signal indicating an excessive output voltage supplied to the output of the power controller is fed to the microcomputer 1 through a power detection line 13 and the microcomputer is operated to shut off the power output. if

  it is appropriate and to activate the alarm signals.

  Computer programming ensures that an "unsafe" or "not available" combination of selected parameters is transmitted to the rest of the unit

  and that an alarm condition is indicated if it is appropriate.

  In this embodiment, the amplifier circuits 7m and 7b are inherently protected against excessive current and this avoids the need for a thermostat to monitor the temperature.

reached by these amplifiers.

  The electrosurgical unit is provided with various acoustic and visual displays that are connected to respective outputs of the microcomputer to transmit to the user information on the state of the unit and provide alarm signals. In the unit shown in FIG. 2, the microcomputer 1 provides a one-bit output signal, via respective current buffers, to connect a respective one of the three visual displays 14a-14c to indicate which of the three main modes

is in action.

  Nine light-emitting diodes 15a-15 indicate which of the disallowable secondary modes of operation was selected and other unit 4tai information in response to a respective signal at

a bit coming from the microcomputer.

  The power output adjustment selected by means of the corw; Power level readers 5a to 5c are read by the microcomputer 1 and displayed by a respective display, ie the three display devices - a: r's 16a to 16c. Each bar display is actuated by an eight-bit signal coming from the microcomputer 1 through a digital-to-analog converter

respective 17a to 17c.

  The microcomputer is also programmed to communicate to the user, via

  visual display devices, function parameters,

  which are available before selection. Accordingly, at each stage of the unit setting process, the appropriate display (s) in a respective series of visual displays 14a to 14c, S15a at 15h and 16a to 16c are illuminated so as to indicate those of selection options that are available and as a result

  guide the user to an appropriate combination.

  In a fault or alarm state, the microcomputer sends a one bit signal simultaneously to an acoustic and visual indicator device 18, passing through a current buffer and the two muting lines 8m, 8b, so cut the power

  of the two outputs, unipolar and bipolar.

  In another embodiment, when a fault or alarm state occurs, the microcomputer 1 also outputs an eight-bit signal to the alarm code visual display device to indicate the type of alarm.

  Fault status / alarm detected.

  In yet another embodiment, the eight-bit binary signal indicating the type of alarm or fault state that has occurred is provided by the microcomputer 1 to an integrated circuit for synthesizing speech to provide To the user, so

audible the appropriate information.

  Instead of the bar display devices 16a to 16c, the unit may include a seven segment digital display for level display.

chosen power.

  In another embodiment, the microorganism

  The controller is programmed so that the unit performs a self-diagnostic test routine when turned on and / or when instructed to do so by operating a manual switch. In this routine, for example, all the visual and acoustic indicators, 14a to 14c, 15a to 15h, 16a to 16c and 18 are activated in a specified order in advance and the failure of any of the components or sub-systems of the unit that can transmit information to the user can be recognized before the elec- toral surgery unit is used. In yet another embodiment, the voltage between the active and the plate electrodes is monitored periodically by the microcomputer together with the output current and the actual power supplied by the unit is calculated and compared to the output power. chosen by the user. If there is

  these values a discrepancy that exceeds a predetermined limit

  mined, the microcomputer activates alarm signals

and / or cut the power output.

  In another embodiment, the microorganism

  the voltage and current appearing on the active electrode, the "crimp factor", which is expressed Vcrate e by and fixes these quantities so as to ensure a high crest factor and therefore a speed

optimal coagulation.

  In another embodiment, the microproces-

  monitors the resistance of the active electrode during a cutting or coagulation process and controls the output current to ensure that it is always

an optimal value.

  Since the shape and level of the output voltage of the electrosurgical unit can be directly controlled by the microcomputer, in all practical respects a 3-0 number can be obtained from these combinations. This flexibility means that the unit is particularly suited to the use of research in the development of

  surgical diathermy techniques.

  In addition, the unit of the invention may be used in conjunction with additional devices to detect the physiological condition of the patient and / or the iss4 at the diathermy site, the output of these diagnoses being brought directly, going through a trench, to the microcomputer of the unit where it is

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  collated and stored with the corresponding operating data for subsequent analysis. The microcomputer may also monitor this incoming physiological data to indicate undesirable physiological effects so that, where necessary, appropriate signals may be emitted by the microprocessor to shut off the power output and / or activate alarm signals. As already explained, the overall operation of the microcomputer and consequently the output of the unit is determined by the program in the program memory which can be formed for example of a read-only memory, a programmable read-only memory, an electrically programmable read-only memory or similar device. Thus, by simply replacing the corresponding integrated circuit (s), the operation of the electrosurgical unit can be customized. In addition, in a preferred embodiment, the unit is adapted so that the user can himself modify the operating program by replacing a preprogrammed memory device. This allows each user to adapt the output of an electrosurgical unit to ensure a particular selection of output waveforms and power levels according to his or her preference and / or the surgical process to be performed. In yet another embodiment, the microcomputer can be connected by means of a bus to an external computer for data acquisition and reprogramming of the electrosurgical unit.

by this computer.

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Claims (13)

R E V E N D I C A T I 0 N S   1. Electrosurgical unit for use in surgical diathermy, characterized in that it comprises a microcomputer (1) for controlling the output of the unit, the microcomputer being connected so as: a) to be addressed by one or more signals coming from a user interface for selecting a desired output from the electrosurgical unit, and means for sampling, in one or more   locations, the electrical state of the electrosurgical unit   and (b) providing one or more control signals to an energy generating circuit for producing the output energy of the electrosurgical unit and at one or   several devices for transmitting to the user   information about the state of the electrochemical unit rurgicale.   2. Unit according to claim 1, characterized   due to the fact that the waveform configuration   the output of the unit is generated by the microcomputer.   3. Unit according to claim 2, characterized   due to the fact that the waveform configuration   is generated by means of counter-timer chips.   4 unit according to any one of the claims   1 to 3, having a unipolar output and characterized in that the power generating circuit comprises a power controller whose output voltage is determined by the microcomputer and a power amplifier circuit for providing a selected output at the unipolar output and to which the output voltage of the power control member is provided   and a computer waveform configuration.   5. Unit according to any one of the claims   1 to 4, having a unipolar output and characterized in that a safety circuit is provided for monitoring a plate electrode circuit connected to the unipolar output.   and has an output connected to the microcomputer.   6. Unit according to any one of   Claims 1 to 5, having a bipolar output   and characterized by the fact that the power generating circuit comprises a power amplifier circuit for supplying power to the bipolar output and to which, at respective inputs, a determined voltage and waveform configuration is provided by the microcomputer.   7. Unit according to any one of the claims   1 to 6, having a bipolar output and characterized by the fact that the control of the power supplied to this bipolar output is achieved by modulation. group of pulses.   8. Unit according to any one of the claims   1 to 7, adapted to provide power at a selected output, unipolar or bipolar and characterized in that the unipolar and bipolar output power is generated in a respective circuit, between   two circuits isolated from each other.   9. Unit according to claim 8, characterized   in that means are provided for inhibiting the power supply at the unipolar output during the bipolar power supply, and at the bipolar output   during unipolar power supply.   Unit according to claim 9, characterized   in that if one or more signals received by the microcomputer   indicate a fault or alarm state, the inhibiting means are activated by the microcomputer so as to inhibit the power supply at least at the output unipolar.   11. Unit according to any one of   Claims 1 to 10, characterized in that the microcomputer is reprogrammable.   12. Unit according to any one of   Claims 1 to 10, characterized in that   the microcomputer has a program memory in the form of a plug-in preprogrammed device   which can be replaced by the user.   13. Unit according to any one of   claims 1 to 12, characterized in that the   microcomputer is programmed to perform a self-diagnostic test routine