US3100489A

US3100489A - Cautery device

Info

Publication number: US3100489A
Application number: US687150A
Authority: US
Inventors: Russell W Bagley
Original assignee: Medtronic Inc
Current assignee: Medtronic Inc
Priority date: 1957-09-30
Filing date: 1957-09-30
Publication date: 1963-08-13
Anticipated expiration: 1980-08-13

Description

Aug. 13, 1963 R. w. BAGLEY CAUTERY DEVICE Filed Sept. 30, 1957 IIIIIIIIII!!! I!!! 0 ll M 0 RL v. mm E E5 m w m Mm R% B United States Patent Filed Sept. 30, 1957, Ser. No. 687,150 6 Claims. 01. 128303.17)

This invention relates to a control unit for a radio frequency cautery instrument or the like. More particularly, this inventionrelates to the combination of an elec tro-coagulation forceps with a relay control unit for actuating cautery instruments.

It is a common practice in some surgical techniques to use radio frequency currents forthe cauterizat-ion or electro-coagulation of small blood vessels and the like. The usual practice is to control the operation of the radio frequency apparatus by a switch operated by a foot edal at the surgeons command. The use of foot pedal control has been fraught with danger, both to the patient and to the surgeon. According to prior practice, it has been necessary for the surgeon to contact the tissue to be canterized and then with his foot actuate the foot pedal switch. Often this necessitates removing his eyes from the operative field to locate the foot switch. There has been the possibility of accidental cautery of edges of incisions and adjacent tissues and the like. There has also been the possibility of burning surgeons hands. In addition, there has been the possibility of 110 volt shock dueto faulty wiring in the foot control.

It is the principal object of this invention to afford the surgeon absolute control of electro-coagulations by providing acontrol unit for radio frequency apparatus actuated by a switch in the forceps through a relay.

It is a further object of this invention to overcome the deficiencies of existing control units for radio frequency cauterizing apparatus by providing an insulated electrocoagulation forceps having a built-in control switch automatically operative from the surgeons hand through a relay control unit.

Other objects of the invention will become apparent as the description proceed-s.

To the accomplishment of the foregoing and related ends, this invention thencomprises the features hereinafter fully described and particu-larly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

The invention is illustrated by the drawings in which the same numeralsrefer to corresponding parts and in which:

FIGURE lis schematic and diagrammatic representation of a radiofrequency cauterizing circuit as used surgically in conjunction with the forceps and relay control according to this invention;

, FIGURE 2 is a side elevation of the electro-coagulat-ion [forceps according to this invention;

FIGURE 3 is a sectional view taken generally along the lines 3-3 of FIGURE 2 and in the direction of the arrows; and

.FIGUR.E 4 is a circuit diagram of the relay control unit.

Referring to FIGURE 1 of the drawings, a radio frequency cautery instrument is indicated generally at 19. This instrument is a standard device, the construction of which forms no part of this invention except that it is controlled by the forceps and relay of this invention.

Qneexample of such a conventional radio frequency apparatus is illustrated and described in United States Patent 31,100,489 Patented Aug. 13, 1963 1,841,968. It is to be understood that the contnol unit of this invention is not limited to any specific cautery instrument but may be adapted to any such present instruments.

The instrument It) is provided with a plug 11 attached to a cord 12 by which the instrument is connected to the ordinary available commercial electrical current. In most instances, this will be volt, 60 cycle alternating current, but, of course, such instruments may be adapted to operate from standard current of different voltage. The instrument is provided with a single terminal socket 0r jack 13 by means of which a radio frequency current conductor 14 may be connected to the instrument. The radio frequency line 1-4 is connected by means of a sin gle terminal socket or jack 15 to a relay control unit or box indicated generally at 16. The radio frequency instrument 10 is provided With a multiple terminal socket 17 by which it is connected through a multiple conductor cable or cord 18 to a similar multiple terminal socket 19 in the relay control unit 16 for purposes which will be explained in detail hereinafter. The instrument 10 is also provided with a single terminal jack or socket 20- through whichit is connected by means of a conductor 21 to a ground plate 22 which is in contact with the body of a patient, indicated generally at 23, for grounding the patient to the instrument to complete the path of'the radio frequency circuit.

other conductor 26 from the relay box 16 is connected in electrical contact with a switch contact element 29 disposed on the inner surface of the other arm of the forceps but electrically insulated from the forceps. Conductor Wire 26 is likewise electrically insulated from the forceps body.

The

switch contacts

28 and 29 are disposed on the inside surfaces of the arms of the forceps so as to touch one another when the forceps arms are closed under pressure of the surgeons fingers to bring the

tips

30 and 31 together. The curvature of the arms of the forceps is preferably such that after the tips 30 and 3:] are brought together, a slight additional pressure is required to bring the switch contacts 28 and 29' together. The conductor 25 may desirably be connected to the forceps body by means of any suitable connector member 32 riveted as at 33 or soldered, welded or otherwise secured in contact with the metal forceps body. The switch contact surface 28 is direct metallic contact with the forceps body, and is rigidly secured by means of riveting, soldering, welding or the like. The switch contact surface 29 on the other hand is provided with a conducting metallic pin 34 which extends through the side arm of the forceps and is insulated from it by means of a sleeve 35 of insulating material set in an opening in the forceps arm. The conductor '26 is soldered or otherwise suitably attached to the pin 34 of the switch contact 29. The entire surface of the forceps with the exception of the switch con-

tact surfaces

28 and 29 and the forceps tips 30* and 31 are provided with an over-all pliable insulating coating of rubber or synthetic rubber-like material applied by dipping, brushing, etc. and indicated at 36. The conductor 26 is spaced and insulated from the metal of the forceps body by an intermediate layer of the insulating coating.

Referring to FIGURE 4 there is shown a circuit diagram of the relay control unit 16. A conductor 37 I carries the radio frequency current between the terminal of socket 15 and one of the terminals of the socket 24 from whence it is passed through conductor 25 to the body of the forceps 27. The relay circuit includes a 12.6 volt transformer 38 the primary of which is connected by means of conductors 39 and All to terminals .41 and 42 of the socket 19'. By this means, the primary of the transformer draws through the multi-conductor cable 18 from the power circuit of the cautery instrument it).

One side of the secondary of transformer 38 is connected in series through a conductor 43 to the choke coil 44 of a relay. The double pole, single throw switch 45 is connected by means of conductors 46 and 47 to terminals 48 and 49 of the multiple socket 19. The

switch45 is thus connected through the cable 18 to the operating circuit of the cautery instrument it to control the operation of that circuit. The contacts of switch 45 :are normally disengaged when coil 44 is deenergized and are brought into engagement when the coil is energized. The relay box is grounded through I conductor 56 to terminal 51 of the socket l9 and thence through the multiple conductor cable 18 to the ground circuit of the cautery instrument 10. r

The other side of the secondary of the transformer 38 is connected through a conductor 52, a 4 mh., 600 ma. radio frequency choke 53 and aconductor 54 to the terminal 55 of socket 24 and thence through conductor 26 to-the switch contact surface 29 on the forceps. The opposite side of relay choke coil 44 is connected through conductor 56, a 4 mh., 600 me. radio frequency choke to the metal relay box are connected across the radio frequency chokes on the low frequency relay side the circuit. I

The radio frequency choke circuit acts as a low pass filter unit to insulate the relay circuit from the high frequency radio current. The chokes have high reactanceto radio frequency current and tend to isolate radio frequency flow to prevent loss of radio frequency current to the relay circuit which is grounded. The con- ;densers 61 and 62 have low reactance to radio frequency current and tend to hold the relay circuit side of the chokes at ground potential so far as radio frequency current is. concerned. The condenser 60 has low reactance to radio frequency current and effectively shorts the control wires so far as radio frequency current is concerned.

The resistance 59 is a limiting resistance to protect the condenser against surges in current. The double pole relay switch is used as a safety factor. A single pole switch would be effective to control the cautery instrument but a double pole switch insures better contact and prolongs the life of the relay unit. Twelve vol-t current is induced in the transformer secondary coil although only 6 volt is required by the relay. However, about lralf of the voltage is lost across the radio frequency chokes which have high internal resistance.

In the operation of the control device of this invention, the patient 23 rests in-contact with plate 22 which is grounded to the cautery, instrument 10. A radio frequency circuit runs from the cautery instrument through conductor 14 to the relay box, through con.-

.ductor 37 in the relay box, through conductor '25 to the forceps, through the forceps to the patient and thence to the ground plate and conductor 21 back to the cautery'instrumeut. The relay box 16 is grounded to the cautery instrument and the relay circuit is powered from the power circuit of the cautery instrument;

The operating (radio frequency generating) circuit runs from the cautery instrument 10 to the relay box 16, through terminal 48 and conductor 46 to the switch 45 and back through'the conductor 47 and terminal 49' to the cautery instrument 10 So long as the forceps switch control circuit is open switches 45 are open and the cautery instrument is inoperative. The control circuit is powered through the tnansformer'lls' and runs from the secondary to the relay coil 44, through radio frequency choke 57, through radio frequency conductor 37 and through conductor 25 to the forceps 27 and switch contact surface $8 and thence from switch contact surface 29, through conductor 26 and radio frequency choke 53 back to the secondary of the transformer. It will be noticed thata portion of conductor 37, all of conductor 25 and a portion of the forceps 27 carry both high radio frequency current and low frequency control current. i v

The operating surgeon grasps the tissue to be cauterized between the exposed tips 30' and 31 of'the forceps 27. 'With the tissue thus grasped, he then exerts the slight additional amount of pressure required to bring

contacts

28 and 29 together to close the controlswitch and complete the control circuit. Current then flows from the secondary of the transformer 38 to the relaycoil to energize its core to actuate switch 45 to close it. With switch 45 'clo'sedthe operating circuit of the radio frequency apparatus is closed. Radio frequency current is genera-ted and flows through the previously described ci-rcuitto the patient 23.

As soon as the desired coagulation has taken place, the

, surgeon relaxes his grip upon the forceps. The normal spring tension of the forceps separates the contact surfaces 28'and 2? to open the control switch and break the control circuit. Current then ceases to pass through the circuit, the relay is de energized and switch 45 is opened therebyshutting off the operating circuit of the cautery instrument. I

The surgeon is provided with immediate and absolute 7 in a conventional foot control has been eliminated. The

loss of radio frequency current to'the relay circuit during cauterization is prevented by the'radio frequency choke.

Although the construction of the device of this invention has lbeendescribed with specific reference to a 110 volt, -60 cycle alternating operating current and various circuit elements have beenidescribed by reference to their specific resistances, inductances, capacities, etc., it will be understood that this represents merely a preferred embodiment of the invention and those specifically described elements may have varying relative values.

It is apparent that many modifications and variations of this invention as herein-before set forth may be made without departing from the spiritfand scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

I claim: V

1. A control unit for .a radio frequency cautery instrument, said control unit comprising a forceps comprising a pair of opposed elongated forceps arms secured together at one end and adapted to be brought together at their free ends by slight pressure on the opposite arms, a pair of electrical switch contact elements positioned on the respective inside surfaces of said forceps arms intermediate of their free and secured ends, said switch elements being positioned to come into contact with each other upon application of pressure to the outside surfaces of said forceps arms, one of said switch contact elements being in direct electrical contact with the body of said forceps, the second of said switch contacts being electrically insulated airornsaid :Eorceps body, a first electrical conductor secured in electrical contact with said forceps body and first switch contact element, a second electrical conductor secured in electrical contact with said second switch con-tact element but electrically insulated from said forceps body and an insulating coating covering all of said forceps except the tree end tips and said switch contact elements, means for connecting the first conductor secured in electrical contact with said forceps body and first switch contact element to the radio frequency output terminal of said cautery instrument, a relay having an operating coil and cooperating movable and fixed contacts, said contacts being normally disengaged when said coil is deenergized and normally engaging one another when said coil is energized, means for connecting said relay contacts in the operating circuit of said cautery instrument to govern the operation thereof, a transformer having a primary and secondary, a power circuit adapted for connection to an alternating current power supply and including said primary, the secondary being connected in series with one of said forceps conductors and the operating coil of said relay, the operating coil of the relay also being connected to the other of said forceps conductors, and a low pass filter unit in the circuit between said forceps conductors and said relay.

2. A control unit according to claim 1 further characterized in that said low pass filter unit includes a parallel pair of radio frequency chokes.

3. A control unit according to claim 2 further characterized in that a pair of condensers and a ground connection are connected across the circuit containing said radio frequency chokes between the chokes and relay.

'4. A control unit according to claim 2 further characterized in that a limiting resistance and condenser in series are connected across the circuit containing said radio frequency chokes between the chokes and forceps contact elements:

5. A control unit according to claim 1 further characterized in that means are provided for grounding said low pass filter units to said cautery instrument.

6. A control unit according to claim 1 further characterized in that means are provided for connecting said power circuit to the power circuit of said caute-ry instrument.

References Cited in the file of this patent UNITED STATES PATENTS 1,071,978 Wlhite Sept. 2, 1913 2,012,937 Benoy Sept. 3, 1935

Claims

1. A CONTROL UNIT FOR A RADIO FREQUENCY CAUTERY INSTRUMENT, SAID CONTROL UNIT COMPRISING A FORCEPS COMPRISING A PAIR OF OPPOSED ELONGATED FORCEPS ARMS SECURED TOGETHER AT ONE END AND ADAPTED TO BE BROUGHT TOGETHER AT THEIR FREE ENDS BY SLIGHT PRESSURE ON THE OPPOSITE ARMS, A PAIR OF ELECTRICAL SWITCH CONTACT ELEMENTS POSITIONED ON THE RESPECTIVE INSIDE SURFACES OF SAID FORCEPS ARMS INTERMEDIATE OF THEIR FREE AND SECURED ENDS, SAID SWITCH ELEMENTS BEING POSITIONED TO COME INTO CONTACT WITH EACH OTHER UPON APPLICATION OF PRESSURE TO THE OUTSIDE SURFACES OF SAID FORCEPS ARMS, ONE OF SAID SWITCH CONTACT ELEMENTS BEING IN DIRECT ELECTRICAL CONTACT WITH THE BODY OF SAID FORCEPS, THE SECOND OF SAID SWITCH CONTACTS BEING ELECTRICALLY INSULATED FROM SAID FORCEPS BODY, A FIRST ELECTRICAL CONDUCTOR SECURED IN ELECTRICAL CONTACT WITH SAID FORCEPS BODY AND FIRST SWITCH CONTACT ELEMENT, A SECOND ELECTRICAL CONDUCTOR SECURED IN ELECTRICAL CONTACT WITH SAID SECOND SWITCH CONTACT ELEMENT BUT ELECTRICALLY INSULATED FROM SAID FORCEPS BODY AND AN INSULATING COATING COVERING ALL OF SAID FORCEPS EXCEPT THE FREE END TIPS AND SAID SWITCH CONTACT ELEMENTS, MEANS FOR CONNECTING THE FIRST CONDUCTOR SECURED IN ELECTRICAL CONTACT WITH SAID FORCEPS