US 2708933 A
Description (OCR text may contain errors)
May 24, 1955 w. AUGUST 2,708,933
GAS BLANKETED ELECTRO-SURGICAL DEVICE Filed May 17. 1951 FIG. L
INVENTOR. A WML/AM ,4am/5T www ATTORNEY Unite anni GAS HSURGECAL DEVlCE Wiliiam August, hat' Rockaway, N. Y.
Appiication May 17, 95E-r, Serial No. 226,i7
3 Claims. (Qi. E28-$03.14)
The present invention relates to electrosurgical devices and more particularly to devices of this character in which the cutting action of a surgical instrument is produced in large measure through energization of the instrument by a high frequency current of appropriate characteristics. High frequency current of somewhat diiferent characteristics may also be employed for purposes of coagulation in connection with the incision.
From the foregoing it will be apparent that during the use of an electrosurgical instrument of this character there will be a tendency to produce a spark as the cutting instrument is brought into proximity to the tissue to be cut. It is common practice, in the course of an operation, to administer an anaesthetic to the patient which anaesthetic may be of a highly explosive character, such as ether vapor, for example.
Accordingly, it is among the objects of the invention to provide an electrosurgical instrument which may be safely employed in the presence of ether fumes or other explosive vapors without danger of causing an explosion.
Another object of the invention is to provide an electrosurgical instrument in which freedom from explosion hazard is obtained without detriment to the usefulness or to the convenience of manipulation of the instrument.
A further object of the invention is to provide an electrosurgical instrument having an interlock arrangement which will prevent the device from being electrically energized unless the explosion prevention feature is prepared for operation.
Other and further objects will become apparent upon reading the following specification together with the accompanying drawing forming a part hereof.
Referring to the drawing:
Fig. 1 is a diagrammatic representation of an embodi ment of the invention.
Fig. 2 is an enlarged view in sectional elevation of a surgical instrument embodying the invention.
Fig. 3 is a sectional View of a pressure switch used in practicing the invention.
Fig. 4 is a schematic diagram of the electrical circuit of an embodiment of the invention.
Referring to Pig. 1, there is shown the fragmentary upper portion of a storage tank l1 of usual construction for the retention and storage of compressed gases and similar substances. Tank 11 is shown provided with a pressure reducing valve 12 having an adjustment knob 13 and a pressure gauge 14. The low pressure side of reducing valve 12 is shown connected by a ilexible hose or tubing 15 to a gas-tight housing 16.
Disposed within gas-tight housing 16 is a high frequency generator 17 which may be of any well-known type appropriate for producing the cutting current or coagulating current for use with electrosurgical instruments.
A generator 17 is shown provided with an output terminal 18 to which a flexible conductor 19 is connected for carrying the high frequency current to the surgical instrument.
The exible conductor 19 extends through a exible Cir hose or tubing 20 to a surgical instrument designated generally as 21. The tubing 20 which interconnects the gastight housing 16 and the instrument 21 is constructed to carry gas under pressure and also to accommodate the ilexible conductor 19 without interfering with the how of gas. The walls of the flexible tubing 2t) may also serve as electrical insulation for the conductor 19.
Referring to Fig. 2, it will be seen that the surgical instrument 21 comprises a rigid handle portion 22 of electrically insulative material. The exible tubing 2t) is shown suitably secured to the handle 22 at one end thereof. Extending axially within handle 22 is a hollow electrically conductive member 23. The flexible conductor 19 is connected to one end of the said hollow member 23, the other end of the said member 23 being shaped for engagement with a knife holding member 24. A length of electrically conductive rigid hollow tubing 25 forms a part of the knife holding member 24. The tubing 25 is xedly secured in and extends axially through the knife holding member 2d, its interior being shaped for engagement with the shank portion 2e of a removable cutting blade 27.
The knife holding member 24.- niay be threadedly secured to the handle member 22 thus bringing one end of hollow tubing into firm engagement with the adjacent end of hollow electrically conductive member 23. The s ik portion 25 of the blade 27 is removably held in tube 25' by radialiy extending iin portions 2S on the tool shank which engage the inside surface of tube 2S. The blade 27 is thus securely although removably heldr in proper working position and the fin portions 2S of its shank 26 provide longitudinal passage for the flow of gas lengthwise of blade 27. it is understood that any other suitable type of cutting blade may be employed in place of the blade 27.
A form of high frequency generator is shown illustrativeiy in Fig. 4, only the schematic circuit diagram be- Iing indicated. Other forms of high frequency generator may 'oe used, if desired, as long as they produce the required amount of power at the desired frequency and with the proper voltage and wave-shape characteristics. ln the embodiment illustrated in Fig. 4, a suitable source of power 39 is connected through contacts 3i-32 of an electromagnetic cut-or' switch 33 to the primar winding 3d of a step-up transformer designated generally as 35.
Primary winding 34 is shown provided with a plurality of voltage taps 36 which may be selectively contacted by a movable switch arm 37, this arrangement being provided to permit compensation for variations in line voltage supplied by source Disposed on top of gas-tight housinf7 Std is a pressure switch di) communicating directly with the interior of housing le through a short pipe 43.. The pressure switch 4i) comprises a pressure chamber L52 which is at the ame pressure as the interior of housing 16 by reason of the short interconnecting pipe The chamber is closed at its upper side 'oy a iiexible diaphragm 43 which is displaced in accordance with variations in the pressure of the gas in chamber .Directly above the pressure chamber d2 is a further chamber 4d closed by a removable screw-type cover d5. Disposed in the chamber 44 are a pair of fixed contacts #t7 and 423 arranged for selective engagement with a movable contact member 49. One end of the contact member 49 is fixedly pivoted at Sd, the opposite end being movable for engagement with either of the two fixed contacts i7 and A link member interconnects diaphragm 43 and movable contact member d?. When the pressure in chamber l2 and hence in housing i6 is low, engagement between contacts 4e* occurs and correspondingly similar engagement between contacts 4'7-49 occurs when the pressure in chamber 4Z is at a high value. By means well known in the art, the pressure values at which contact closure occurs may be made adjustable and may be brought within almost any desired range of pressures.
Winding 52 of cut-off switch 33 is connected vra a conductor 53 to both contacts 47 and 4S in multiple, movable contact 49 being connected via conductor 54 to one side of the power source 3b. Engagement of the movable contact 49 with either of the two stationary contacts 67 or 48 will energize operating winding 52 of switch 33 causing it to open its contacts 3ft- 3&3 and thus prevent energization of primary winding 34 of step-up transformer 35. One side of power source 36 may be connected through a foot-operated switch 56 to one side of the primary winding 34 of transformer 35. Accordingly, primary winding 34 may be energized upon closure of foot switch 56 unless contacts 31-32 of cut-off switch 33 have been caused to open by either a high or low pressure condition at pressure switch 4t).
A plurality of spark gaps 6G are connected for energization by the high-voltage secondary winding 61 of transformer 35. High frequency oscillatory currents are induced in a resonant circuit comprising a high-frequency tuning coil 62 and capacitors 63. These high frequency currents are shown by way of illustration as being taken off through coupling capacitors 64, one of these capacitors being connected to a ground terminal 65 and the other being connected to output terminal 18. A suitable ground electrode 66 is shown connected to terminal 65 by a conductor 67. Ground electrode 66 is intended, as and when required, to complete the circuit to the body of the patient undergoing the operation.
In use, inert gas at appropriate pressure is admitted into the housing 16 from storage cylinder 1.1 through reducing valve 12 and tubing 15, the pressure being indicated by gauge 14. lf the correct pressure prevails in housing 16, then the contacts 47-48-49 of pressure switch 4t) will all be open and consequently the contacts of cut-off switch 33 will be closed thereby permitting energization of transformer 35 from source 38 upon closure of foot switch 56 which is serially included in the transformer primary circuit. If the pressure in housing 16 is either too high or too low, the transformer 35 cannot be energized.
The gas in cylinder 11 is preferably an inert gas and may be of any suitable type such as carbon dioxide, neon, helium, etc. The principal requirement is that the gas shall not be capable of forming an explosive mixture with air, nor with the fumes of any other gas or vapor which may be used for purposes of anaesthesia. The gas must, of course, be sterile and of such concentration as to be non-toxic insofar as the patient and the operating room personnel are concerned.
The inert gas from housing 16 passes through tubing 2t? and through hollow member 23 entering tubing 25 and flowing around tin portions 28 of removable knife 27. The shape of the cooperating portions of knife 27 and the other parts of instrument 21 which form passages for the inert gas is such that they constitute a nozzle causing a smoothly flowing envelope of inert gas to surround completely the knife 27. By maintenance of the gas pressure in housing 16 within suitable limits, turbulence of the envelope may be avoided and the gas flow will always be of sufficient volume to insure adequate thickness of the explosion preventing gaseous envelope. The actual dimensioning of the gas passages in any particular case will depend upon the gas pressure together with the size and shape of the cutting implement. Any spark which may occur within the envelope of inert gas cannot ignite an explosive mixture outside the envelope.
It will also be noted that the presence of gas under pressure in housing 16 which encloses high frequency generator 17 will avoid any danger of an explosion being caused by any spark emanating from the high frequency generator 17. No explosive vapor can enter housing 16 since it is filled with inert gas under pressure. -Moreover, any explosive vapor which may have entered housing 16 during a period of idleness or accumulated in some other manner will immediately become'diluted by circulating inert gas passing from storage tank 11 to surgical instrument 21.
In accordance with the U. S. patent statutes, I have shown what l believe to be the best embodiment of my invention. I do not wish, however, to be confined to the embodiment shown, but by the invention as defined in the appended claims.
l. A gas-blanketed electrically energizable surgical cutting apparatus including a cutting instrument for use in an atmosphere which may be of an explosive nature, comprising means for energizing the cutting instrument being connected to said instrument, a source of gas under pressure, conduit means connected to the apparatus for conveying gas from said source to the cutting instrument; nozzle means surrounding said cutting instrument and connected to said gas conveying means for causing the gas to form an envelope surrounding those portions of the cutting instrument at which a spark is likely to occur, and pressure controlled switching means interposed between the source of gas and the energizing means for preventing energization of the cutting instrument upon deviation of the gas pressure outside predetermined limits.
2. A gas-blanketed electrically energized surgical apparatus including a cutting instrument, comprising: a handle portion having a passage therein for an inert gas under pressure, said cutting instrument being removably carried by the handle portion, and nozzle means comprising the engaging portions of the handle portion and the cutting instrument for causing the inert gas to surround those portions of the cutting instrument at which a spark may be likely to occur, means for energizing the cutting instrument connected to said instrument, and pressure actuated switching means in communication with said passage and connected to prevent energization of the cutting instrument upon deviation of the gas pressure in said passage outside predetermined limits.
3. A gas-blanketed electro-surgical device, comprising: a handle portion having a passage therein for an inert gas under pressure, a cutting portion removably carried by the handle portion, nozzle means communicating with said passage and comprising the engaging portions of the handle portion and the cutting portion for causing the inert gas to form an envelope surrounding those portions of the cutting instrument at which a spark would be likely to occur, a gas tubing engaging one end of said handle portion and communicating with said passage, an electrical conductor disposed within said tubing and connected to said cutting portion for energizing said cutting portion, a housing, the other end of said tubing being in communicative engagement therewith, a source of high frequency current disposed within said housing, said electrical conductor being connected to said source, and pressure actuated switching means exposed to gas pressure in said housing responsive to said gas pressure for rendering said source inoperative upon deviation of the gas pressure within the housing outside of predetermined limits.
References Cited in the file of this patent UNITED STATES YPATENTS 1,813,902 Bouie July 14, 1931 2,376,265 Meredith May 15, 1945 2,517,739 Tyrner et al Aug. 8, 1950 2,555,017 Tuthill May 17, 1951 2,618,267 Hanriot Nov. 18, 1952 FOREIGN PATENTS 934,257 France lan. 10, 1948 986,527 France Mar. 28, 1951