Electrosurgery Unit And Instrument

Abstract

An electrosurgery unit for carrying out various medical or dental operations. An oscillator of the unit provides an output signal of a given high frequency, and this signal is received by a pre-amplifier which provides an amplified signal. An output amplifier receives the latter signal and provides a given output, while an output coupler connects the output of the output amplifier to a high-impedence load which in the case of dental surgery may be the gums which are treated. A power supply is provided for supplying voltage to the oscillator, pre-amplifier and output amplifier. For coagulating operations the unit provides a fully modulated high frequency signal. For cutting operations, the unit provides a ripple-free constant amplitude high frequency output. A selecting switch is provided for selecting between the operations.

Description

BACKGROUND OF THE INVENTION

The present invention relates to electrosurgery devices and to instruments capable of being used for carrying out medical or dental operations.

In general there are two types of electrosurgery devices. One type operates with spark gap generators while another type utilizes electronic circuits made up of vacuum tubes with perhaps part of the circuits including semiconductor diodes. This latter type of device is usually undesirably bulky and heavy. It generates an undesirably excessive amount of heat even when it is only in a standby condition. The filaments of the tubes require a given warm-up time, and the time required during the turn-on waiting period is generally longer than the very short time required for the actual operations. The vacuum tubes unavoidably age, so that devices of this type generally require constant servicing.

With conventional devices of the latter type, the power oscillator on indicator, mounted on the front panel of the electrosurgery device, does not indicate positively whether the output current is available at the probe tip. As a result there is a safety hazard for the nurse in the event that she attempts to clean the tip, as by using a piece of gauze.

On the other hand, vacuum tubes are high-impedance devices. The output power thereof can be easily coupled through a probe and tip to the load which is of high-impedance. Also, the output power can easily be varied simply by adjusting the tube screen grid potential.

However, the large bulk and weight of these conventional devices, as well as the constant servicing thereof, with the inconvenience simply involved in the time for waiting for the device to become operative, creates considerable problems which up to the present time have not been solved.

SUMMARY OF THE INVENTION

It is accordingly a primary object of the present invention to provide a unit which will avoid the above drawbacks.

Thus, it is an object of the invention to provide an electrosurgery unit which is extremely small and extremely light.

It is also an object of the invention to provide an electrosurgery unit which will generate heat only during operation, with the heat which is generated during standby being negligible.

It is also an object of the present invention to provide an electrosurgery unit which is capable of achieving for cutting operations a constant amplitude signal, commonly referred to as a fully rectified current.

Also, it is an object of the invention to provide an electrosurgery unit which can provide a fully modulated signal, commonly referred to as unrectified current, for coagulating purposes.

It is also an object of the present invention to provide a unit of this type which eliminates all effects of aging, so that servicing due to aging is eliminated.

Furthermore, it is an object of the invention to provide for use with a unit of this type or with other units, an instrument having a probe capable of giving a positive indication that high frequency power is present at the probe tip.

Also it is an object of the present invention to provide an instrument of this latter type which will greatly reduce the possibility of radio frequency interference, so that other electrical units used in the vicinity of the unit of the invention will not be undesirably influenced.

According to the invention the electrosurgery unit includes an oscillator means for providing of signal of given high frequency output. A pre-amplifier means is connected with the oscillator means for providing an amplifier signal, and an output amplifier means receives the latter amplified signal to provide an output therefrom. An output coupler means receives the output from the output amplifier means and couples the output to the high-impedance load which may be the gums in the case of dental operations. A power supply means is provided for supplying voltage to the oscillator means, the pre-amplifier means, and the output amplifier means. A selecting means is connected with the power supply means for selecting between an operation where the cutting circuit means is operative, for cutting operations, or where the cutting circuit means does not enter into the operation, so that coagulating operations can be carried out. The output coupler means includes a coaxial cable of predetermined length connected at one end to a probe which removably carries a probe tip. Within the probe there is visible a neon lamp one lead of which is connected to the probe and the other lead of which has a capacitive relation with respect to the coaxial cable. The neon lamp glows when the voltage at the tip exceeds the breakdown voltage of the bulb.

BRIEF DESCRIPTION OF DRAWINGS

The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a wiring diagram illustrating the circuitry of the electrosurgery unit of the invention;

FIG. 2 is an enlarged sectional illustration of the probe showing the structure in a plane which contains the longitudinal central axis of the probe;

FIG. 3 is a side view of the electrosurgery unit; and

FIG. 4 is a plan view taken along line 4--4 of FIG. 3 in the direction of the arrows and showing the operating panel of the electrosurgery unit.

DESCRIPTION OF PREFERRED EMBODIMENTS

Basically the device of the present invention forms an electrosurgery unit which is in the form of a high frequency power oscillator having an output power applied to the patient at the part which is to be treated. For example, in the case of dental surgery the output power is applied to the patient's gums through a probe and a tip. However, the electrosurgery unit can be used for general medical purposes such as in dermatology to remove various growths at the skin, and for many other medical purposes. A power level control is provided in order to vary the output power to the required amount. Also with the instrument of the invention there is an indicator lamp which either is turned on or which glows brighter in intensity when the high frequency power oscillator is turned on.

The oscillator is capable of achieving a coagulating current and a cutting current. The coagulating current is characterized by alternating surging peaks of energy similar to an amplitude modulated signal with full one hundred percent modulation. This current is used to stop bleeding such as bleeding of the gums. The cutting current is characterized by a constant amplitude signal achieving a constant flow current used for cutting or removing small amounts of flesh, or small amounts of gums in the case of dental surgery.

Referring now to FIG. 1, it will be seen that the electrosurgery unit of the invention includes an oscillator means 10, pre-amplifier means 12, an output amplifier means 14, an output coupler means 16, a power supply means 18 and a power-level control means 20.

The oscillator means is adapted to be turned on or off by actuation of a foot switch 22 of conventional construction. The circuit includes components such as the capacitor 24, the Zener diode 26, and the resistors 28 and 30 as well as the inductance coil 32, resistor 34, and capacitors 36, 38 and 40, all of which are used to achieve the proper impedance matching for the circuitry. However, one of the important features of the oscillator circuit is that it includes a crystal 40 which will achieve a constant frequency signal which is received by the pre-amplifier means 12.

This output signal is received at the base of the pre-amplifier transistor 44. The pre-amplifier includes the variable capacitance 46 as well as the inductance coil 48, the resistor 50, the capacitor 52 and the inductance coil 54. The pre-amplifier means 12 amplifies the high frequency signal received from the oscillator means 10. The amplified signal is fed from the pre-amplifier means to the output amplifier means 14 where it is received at the base of the transistor 56. The output amplifier means includes the various capacitances, inductance coils and resistors illustrated so as to have proper impedance matching.

A further important feature of the invention resides in the power-level control means 20. The pre-amplifier transistor 44 is a class C amplifier. The output of a class C amplifier is proportional to the square of the collector supply voltage. In order to vary the gain of a class C amplifier it is conventional to connect a potentiometer between the supply voltage and the collector of the transistor so that the collector voltage or the amplifier gain can be varied. The result is that a large amount of DC supply power will be dissipated in the potentiometer. A potentiometer of high power dissipation is therefore required for gain control. It is unavoidable, therefore, that with this type of construction a physically large control will be essential and there will be a decrease in the efficiency of the entire design.

In contrast, with the present invention the power-level control means includes the transistor 58, connected into the circuit as a diode, the capacitor 60, and the potentiometer 62. These latter components connected into the circuit as illustrated in FIG. 1 constitute the power-level control circuit means. The circuit is an amplitude detector. It converts a portion of the high-frequency signal at the base of transistor 44 into direct current power. This converted DC power is then dissipated in the potentiometer 62. The amount of signal power which is dissipated depends upon the setting of the potentiometer 62. The more power is dissipated in the potentiometer 62, the less the signal power is amplified by the amplifier means 12 and 14. As a result, the output power of the unit depends on the setting of the potentiometer 62.

The output coupler means 16 receives the output from the transistor 56 of the output amplifier means 14. The output transistor 56 requires a very low impedance on the order of a few ohms depending upon the maximum output power and power supply DC voltage. The impedance of the load, such as the gums in the mouth, has an impedance level on the order of a few thousand ohms. A special coupling network that transforms the output load impedance into the desired collector impedence is required, so that the power generated by the transistor can be effectively transferred to the load. Since the power oscillator operates at a high frequency, a tuned coupling network is required.

Another requirement of the output coupler means 16 is that the output power be connected from the power oscillator by a flexible cable in the form of the coaxial cable 64. This flexible cable is of a few feet in length and is connected to a probe 66 which in turn removably carries through a suitable chuck a probe tip 68, so that one tip can be exchanged for another as required. The cable 64 has a characteristic impedance of 50 ohms. It is not terminated at the probe end. Since the probe length is less than one-quarter of the wave length of the output power signal, the impedance looking into the cable end 70 is capacitive. This capacitor together with the capacitors 72 and 74 in series constitute the output tuning capacitor of the output coupler network. Other components in the network are the illustrated inductor coil and grounded cable shields.

As may be seen from FIG. 2, the coaxial cable 64 extends into the tubular housing 76 of the probe 66. This tubular housing has a transparent tubular wall portion 78 so that a glowing neon lamp 81 will be visible therethrough.

The coaxial cable 64 includes an inner conductor 80 embedded in and surrounded by a suitable dielectric 82. This dielectric 82 is in turn situated within and surrounded by a tubular metallic shield 84 which in turn is covered by the insulation 86. The inner conductor 80 of the coaxial cable 64 is electrically connected directly with the probe 88 provided with any suitable chuck 90 for removably connecting to the probe the operating tip 92. Thus, one operating tip may be exchanged for another. The neon lamp 81 has one lead 94 connected electrically with the lead 80; directly to the probe 88. The other lead 96 of the neon lamp, however, is not connected to any element. It simply rests within the tubular housing 76 at the region of the exterior of the coaxial cable 64 so as to have a capacitive relationship with respect to the shield which is surrounded by the insulation. Thus, this lamp 81 will indicate positively whether high frequency power is present at the tip 92 and therefore forms a means for indicating the presence of high frequency power at the tip. The small capacitance between the lead 96 and the cable shield provides the ground return and also limits the maximum current passing through the neon lamp 81. This neon lamp glows when the voltage at the tip exceeds the breakdown voltage of the lamp.

It is to be noted that the coaxial cable 64 has at its end distant from the probe assembly 66 a prong capable of being received in any suitable receptacle so that the coaxial cable together with the probe and other details of FIG. 2 form a separate instrument which can be used with other suitable sources of energy for general medical, dental, and other like purposes.

The power supply means 18 includes the plug 100 which can be inserted into any wall outlet receptacle for receiving the line voltage. An on-off switch 102 is provided. The line voltage is delivered to a transformer 104 which converts the line voltage into a lower voltage rectified by the bridge rectifier 106. The power from the power supply means 18 is delivered through a conductor 108 to the output amplifier means 14. The power supply means further includes a cutting circuit formed primarily by the large electrolytic filtering capacitor 110, and a diode 112.

For coagulating operations the power supply means 18 will provide a collector supply to the output transistor 56 which has the wave shape of a fully rectified sine wave. This supply voltage modulates the oscillator signal so that the output signal takes the form of a 100 percent modulated signal with alternating peaks of power occurring at twice the line frequency. For selecting this latter type of operation a selecting means is provided in the form of a selecting switch 114 which can be displaced by the operator to the coagulating position in which it is illustrated in FIG. 1. When the switch 114 is in the cut position the diode 112 is shorted and the line ripple is filtered out by the large electrolytic capacitor 110. As a result the supply voltage for the oscillator, pre-amplifier, as well as the output amplifier is line ripple free and the high frequency output has a constant amplitude. When the switch 114 is set to the coagulating position, the diode 112 prevents the line ripple from being filtered by the capacitor 110, with the result that the above fully modulated signal is achieved.

The above-described circuitry, with the exception of the coaxial cable and probe connected thereto can be housed within a suitable housing such as the housing 116 illustrated in side elevation in FIG. 3. All of the above fully transistorized circuitry is enclosed within the housing 116 with the cable which is connected to the plug 100 extending from the housing so that the plug 100 can be connected with a suitable wall outlet or the like.

The housing 116 has at its front upper portion an inclined panel 118 carrying a rotary knob 120 which forms the adjusting element for the potentiometer 62. Referring to FIG. 4, the panel 118 is illustrated therein. The knob 120 coacts with a suitable scale for indicating the adjustment of the potentiometer 62. Available at the panel 118 is also the on-off switch 102. Also the selecting switch 114 capable of being placed either in the cut or in the coagulating position is illustrated. The foot control switch 22 can be removably connected with a receptacle 124. There is also an IND receptacle 126 for receiving a conductor engaged by the patient for forming a ground connection with the patient. The end of the coaxial cable 64 distant from the probe 66 terminates in a prong which can be received in the receptacle 128.

Thus, with a conductor from receptacle 126 properly engaging the patient, with a foot-control switch connected to the receptacle 124, and with the probe 66 of the invention connected to the receptacle 128, it is possible, when the plug 100 is connected to a suitable source, to turn the switch 102 into the on position for starting the operation, and there is virtually no waiting period required for warm-up purposes. Depending upon whether cut or coagulating operations are to be carried out the switch 114 will be placed in one or the other of the positions apparent from FIG. 4.

It is apparent from the above description and the drawings that the fully transistorized electrosurgery unit of the invention overcomes all of the drawbacks of the vacuum-tube type of structure. With the structure of the invention the entire unit can be made quite small and of an exceedingly light weight. The only heat which is generated is generated during the actual operation. Any heat generated during standby is negligible. There is achieved with the circuitry of the invention a proper constant amplitude signal for cutting operations. Also it is possible to achieve for coagulating operations a fully modulated signal, commonly referred to as unrectified current. With the structure of the invention servicing due to aging of the components is completely eliminated. Furthermore, by way of the neon lamp there is a positive indication that high frequency power is present at the probe tip.

Claims

What is claimed is:

1. In an electrosurgery unit, oscillator means for providing an output of a given frequency, pre-amplifier means receiving said output from said oscillator means and providing an amplified signal therefrom, output amplifier means receiving said signal from said pre-amplifier means and providing therefrom a predetermined output, output coupler means receiving said output from said output amplifier means for coupling the latter output to a high-impedance load, power supply means electrically connected with said oscillator means and pre-amplifier means for supplying at all times a constant amplitude output thereto, said power supply means normally providing for coagulating operations a supply voltage in the form of a fully rectified sine wave to said output amplifier means, cutting circuit means electrically connected with said power supply means for coacting therewith to provide an output of constant amplitude, and selecting means coacting with said power supply means and cutting circuit means for selectively operating said power supply means either without said cutting circuit means for coagulating operations or with said cutting circuit means for cutting operations, said oscillator means, pre-amplifier means, and output amplifier means being fully transistorized.

2. The combination of claim 1 and wherein said oscillator means includes a crystal for providing a stable high-frequency output signal therefrom.

3. The combination of claim 1 and wherein a power-level control means is connected with the input of said pre-amplifier means for acting on the output from said oscillator means for converting a portion of the signal therefrom into direct current power and for then dissipating the latter power.

4. The combination of claim 1 and wherein a foot switch is operatively connected with said oscillator circuit means for turning the latter on and off.

5. The combination of claim 1 and wherein said output coupler means includes a coaxial cable of predetermined length and a probe connected electrically thereto and terminating in an operating tip, and a neon lamp connected electrically with the probe and having a capacitive relation with respect to said coaxial cable for glowing when the voltage at the probe tip exceeds the breakdown voltage of said lamp.

6. The combination of claim 5 and wherein said probe includes a selected operating tip and a chuck removably connecting said selected operating tip thereto, so that one operating tip may be exchanged for another.

7. In an electrosurgery unit, oscillator means for providing an output of a given frequency, pre-amplifier means receiving said output from said oscillator means and providing an amplified signal therefrom, output amplifier means receiving said signal from said pre-amplifier means and providing therefrom a predetermined output, output coupler means receiving said output from said output amplifier means for coupling the latter output to a high-impedance load, power supply means electrically connected with said oscillator means, pre-amplifier means and output amplifier means for supplying a voltage thereto, cutting circuit means electrically connected with said power supply means, and selecting means coacting with said power supply means and cutting circuit means for selectively operating said power supply means either without said cutting circuit means for coagulating operations or with said cutting circuit means for cutting operations, said oscillator means, pre-amplifier means, and output amplifier means being fully transistorized, a power-level control means connected with the input of said pre-amplifier means for acting on the output from said oscillator means for converting a portion of the signal therefrom into direct current power and for then dissipating the latter power, said power-level control means including a transistor connected as a diode, a capacitor, and a potentiometer, said capacitor and potentiometer being electrically connected in parallel with each other and in series with the transistor between ground and the input of said pre-amplifier means, and said transistor and capacitor converting the signal from said oscillator means into direct current power and said potentiometer dissipating the direct current power, with the extent of signal power dissipation being determined by the setting of said potentiometer.

8. In an electrosurgery unit, oscillator means for providing an output of a given frequency, pre-amplifier means receiving said output from said oscillator means and providing an amplified signal therefrom, output amplifier means receiving said signal from said pre-amplifier means and providing therefrom a predetermined output, output coupler means receiving said output from said output amplifier means for coupling the latter output to a high-impedance load, power supply means electrically connected with said oscillator means, pre-amplifier means and output amplifier means for supplying a voltage thereto, cutting circuit means electrically connected with said power supply means, and selecting means coacting with said power supply means and cutting circuit means for selectively operating said power supply means either without said cutting circuit means for coagulating operations or with said cutting circuit means for cutting operations, said oscillator means, pre-amplifier means, and output amplifier means being fully transistorized, said cutting circuit means including a filtering capacitor and a diode connected between the latter capacitor and said power supply means for preventing filtering by said filtering capacitor, said selecting means bridging said diode when set for cutting operations to render said filtering capacitor operative.

9. In an electrosurgery unit, oscillator means for providing an output of a given frequency, pre-amplifier means receiving said output from said oscillator means and providing an amplified signal therefrom, output amplifier means receiving said signal from said pre-amplifier means and providing therefrom a predetermined output, output coupler means receiving said output from said output amplifier means for coupling the latter output to a high-impedance load, power supply means electrically connected with said oscillator means, pre-amplifier means and output amplifier means for supplying a voltage thereto, cutting circuit means electrically connected with said power supply means, and selecting means coacting with said power supply means and cutting circuit means for selectively operating said power supply means either without said cutting circuit means for coagulating operations or with said cutting circuit means for cutting operations, said oscillator means, pre-amplifier means, and output amplifier means being fully transistorized, said output coupler means including a coaxial cable of predetermined length and a probe connected electrically thereto and terminating in an operating tip, and a neon lamp connected electrically with the probe and having a capacitive relation with respect to said coaxial cable for glowing when the voltage at the probe tip exceeds the breakdown voltage of said lamp, said coaxial cable including an inner conductor, a dielectric surrounding said conductor, and a shield surrounding said dielectric and covered by insulation, said neon lamp having one lead connected to said probe and another lead terminating in the region of said shield for providing the capacitive relationship therewith.

10. An instrument for carrying out electrosurgical operations, comprising an elongated coaxial cable having at one end a means for connecting the cable to a suitable source, a probe electrically connected with the opposite end of said cable, said probe carrying an operating tip, and a neon lamp carried by said probe for providing a visible signal when said lamp glows, said lamp being electrically connected with said probe and having a capacitive relationship with respect to said cable for glowing when the voltage at said tip exceeds the breakdown voltage of said lamp, said coaxial cable including an inner conductor, a dielectric surrounding the latter conductor, a shield surrounding the dielectric and insulation surrounding the shield, said conductor being electrically connected with said probe and one lead of said neon lamp also being electrically connected with said probe, the other lead of said neon lamp being situated in the vicinity of said shield to have a capacitive relationship therewith.