Finger Actuated Surgical Electrode Holder

Abstract

A surgical electrode holder is provided with an improved finger pressure operated switch that also incorporates an electrode gripping collet. The collet, which is electrically connected to the control circuit for a radio frequency generator, extends through and slides within a metal pipe. An annular switch element having solid ends and a number of metal strips extending between the ends is mounted coaxial to and surrounding the metal pipe by insulating supports at each end of the switch element. The switch element is encased and protected by a stock into which the metal pipe is inserted, a nose piece in front of the pipe and a rubber tube which surrounds the annular switch element and extends from the stock to the nose piece. The radio frequency generator is activated by squeezing the rubber tube to depress one or more of the metal strips, which are electrically connected to the control circuit for the generator and to the output terminal of the generator, and make contact with the metal pipe.

Description

BACKGROUND OF THE INVENTION

This invention relates to a hand tool, and more particularly to a holder for surgical electrodes.

Radio frequency current is used in a number of surgical techniques, including cutting, cauterizing and the like. A variety of systems for supplying the radio frequency current have been developed. In some, a control circuit which activates the electro-surgical generator is completed when the electrode contacts the body. Simple electrode holders can be used with this type of system, but this type of system does not allow the surgeon to position the electrode and be sure that he has it where he wants it before he applies the current.

Another type of system utilizes a foot switch to activate the generator. However, with this type of system the surgeon must coordinate his hand and foot movements. In addition, the foot switch limits the surgeon's freedom of movement, may require him to assume somewhat awkward positions, and requires him to keep track of the switch, all of which can detract from his overall efficiency.

A number of attempts have been made to produce a satisfactory electrode holder with a finger actuated switch in the holder itself. However, most of these holders have been too bulky and/or have required the surgeon to place his hand in a particular position on the electrode holder. Due to the differences in physicians' physiques and operating techniques, a switch that was properly positioned for one physician would require another to place his hand in an awkward position. Another drawback of most prior art electrode holders with finger switches was that they were difficult to clean. Standard hospital practice for cleaning objects such as these holders is to sterilize them by autoclaving or the like. Most electrode holders with built in switches have had crevices or pockets which made them difficult to clean properly.

U.S. Pat. No. 3,089,496 to Degelman discloses a surgical electrode holder which is superior to most prior art electrode holders in that the switch may be closed by finger pressure at any point around an annular metal clip which is divided by slots into four resilient metal leaves. However, the flexibility of these leaves varies across the width of each leaf. Thus, the amount of pressure needed to close the switch varies from point to point around the holder. As a result, the surgeon may accidentally close the switch too soon if he applies pressure at a particularly flexible spot or, conversely, fail to close the switch if he applies the pressure at a stiffer point. In addition, since only one end of the leaves is supported, they must be rather short. Thus, the physician's choice of hand positions is still somewhat limited.

The exposed nature of Degelman's switch element leads to certain other drawbacks. Pockets which are rather difficult to clean are created and the exposed electrical contacts are subject to corrosion during cleaning. In addition, since the switch element is exposed and is only supported at one end, the clip must be rather rugged to prevent accidental closure and/or damage to the switch element from accidental bumps or the like. This limits the amount of flexibility which can be built into the switch, which in turn means that the leaves must be fairly close to the metal ring with which they make contact. As a result, fairly close manufacturing tolerances must be maintained in order to avoid excessive variations in the amount of pressure needed to operate the switch.

It is an object of this invention to provide a surgical electrode holder with a relatively long switching area containing a finger actuated switch that may be operated by approximately the same pressure at any spot within the switching area. Another object is to provide a surgical electrode holder with a finger pressure operated switch which is completely encased to prevent damage to the switch, accidental closure of the switch, corrosion of the switch during cleaning operations and to provide a holder with a smooth outer surface that facilitates cleaning.

Still another object of this invention is to combine a finger operated switch with a spring loaded gripping collet. Different electro-surgical techniques require a variety of different electrodes. Thus, it is desirable to have rapid and easy interchangeability of the electrodes. U.S. Pat. No. 3,494,364 to Peters and U.S. Pat. No. 3,532,095 to Miller et al. disclose surgical electrode holders with spring loaded collets which facilitate replacement of the electrodes. However, neither of these holders incorporate a hand switch. Thus, they can only be used with systems utilizing an automatically activated generator or a generator activated by a foot switch. It is an object of this invention to provide a simple compact electrode holder combining a finger pressure switch with a spring loaded collet.

Other objects and advantages of this invention will be apparent from the following description.

SUMMARY OF THE INVENTION

This invention provides a switch in which one of the contacts is an inner conductive member such as a metal pipe. An annular switch element having a larger diameter than the inner conductive member is mounted coaxial to and surrounding the inner conductive member. The annular switch element has a plurality of flexible, resilient conductive strips which are preferably attached at each end to a solid ring. The conductive strips are normally displaced from the inner conductive member. When one or more of the flexible resilient conductive strips are depressed to make contact with the inner conductive member, the electrical circuit is completed.

In the preferred embodiment of this invention, the electrical connections to the inner conductive member are made through a collet rod which extends through and slides within the conductive member. The front end of the collet is split into several sections to form jaws which are adapted to grip an object, such as a surgical electrode inserted in the jaws. The rear end of the collet extends beyond the conductive member and the electrical connection to this collet is made by a spring contact past which the rear end of the collet slides.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of one embodiment of this invention.

FIG. 2 is a sectional side view of the embodiment shown in FIG. 1.

FIG. 3 is a cross section taken along lines 3--3 of FIG. 2.

FIG. 4 is a detail view of a partially completed switch element for the holder shown in the other figures.

FIG. 5 is an enlarged sectional side view taken along lines 5--5 of FIG. 3.

DETAILED DESCRIPTION

The preferred embodiment of this invention has a stock 11 into which is threaded a short metal pipe 12. An annular switch element, generally referred to as 13, is supported coaxial to and surrounding the metal pipe by an insulating spacer ring 14 slidably mounted on pipe 12 and by a shoulder 15 on stock 11.

Switch element 13 is formed by cutting away portions of a flat metal sheet, a detail view of which is shown in FIG. 4, to form slots 16 which define a plurality of flexible, resilient metal strips 17 that extend between the solid ends 18 of the sheet. The sheet is then bent around a mandrel into an annular shape and retaining rings 19 are slipped over both ends of the sheet and soldered thereto. These retaining rings maintain the annular shape of the switch element.

The switch element is enclosed by stock 11; by a plastic nose piece 20 which slips over and is adhesively bonded to a metal sleeve 21, which in turn is threaded onto the front end of metal pipe 12; and by a rubber tube 22 which surrounds the annular switch element and extends from the stock to the nose piece. Also incorporated in the stock are means, which will be described in greater detail below, for electrically connecting the metal pipe and the annular switch element to the leads from the control circuit for a radio frequency electro-surgical generator. The surgeon activates the generator by squeezing rubber tube 22 to depress one or more of the metal strips 17 to make contact with the metal pipe 12.

As can be seen in FIGS. 1 and 2, the metal strips 17 have outwardly bowed central portions 23 that are farther away from the metal pipe 12 than the ends of the metal strips are. As a result, the pressure needed to operate the switch is approximately the same along the entire length of the switching area.

When the metal strips 17 of the switch element are bowed out in this manner, at least one end of the switch should be free to move longitudinally. If this freedom is not provided, the strips will have a tendency to remain down after they are depressed and keep the switch from opening.

In the illustrated embodiment, freedom is provided by slidably mounting the switch element on the retaining ring 14 and the shoulder 15 on the stock. As is best shown in FIG. 5, both the ring and the shoulder are stepped to provide small ends 24, 25 and adjacent larger portions 26, 27 that are at least as large as the ends of the switch element 13. The ends of the switch element are slidably mounted on the small end 24 of spacer ring 14 and the small end 25 of shoulder 15. The adjacent larger portions 26 and 27 support the rubber tube 22. Gaps 28, 29 are provided between the ends of switch element 13 and the larger portions 26, 27 of the spacer ring and shoulder. These gaps provide room for longitudinal movement of the end of the switch element. Since the rubber tube 22 is supported by the larger portions of the spacer ring and shoulder, the tube does not prevent movement of the switch element in gaps 28 and 29.

Since the metal strips 17 are supported at both ends, the desired spacing between the strips and the metal pipe can be maintained despite the fact that the strips are relatively long and narrow and are quite flexible. As a result, a relatively long switching area is provided and the pressure needed to operate the switch is approximately the same around the entire periphery of the switching area. Thus, the surgeon is not forced to adapt his grip to fit the switch. In addition, since the strips are long and flexible, they can be spaced a reasonable distance away from the metal pipe. Thus, a reasonably uniform operating pressure can be achieved without extremely close manufacturing tolerances.

The number, width, length and thickness of the strips may be varied to suit a number of different manufacturing techniques as long as enough strips are provided so that the pressure required to operate the switch remains fairly uniform around the periphery of the switching area. For most methods of manufacture, as the number of strips is reduced the manufacturing cost will be reduced somewhat. However, a point is eventually reached where excessive variations in the operating pressure will occur. For the manufacturing technique described above, we have found that a satisfactory balance of these practical consideration is achieved when the switch element has at least seven strips which are separated from each other by slots approximately as wide as the strips.

The pressure needed to operate the switch can be modified easily by changing the width, thickness, and/or the length of the strips. Thus, a variety of switch elements may be provided so that each surgeon can have a holder which operates at the pressure that suits him best.

Since the switch element is protected by the nose piece and stock, both of which are larger in diameter than the switch element, the chances of accidentally closing the switch and/or damaging the switch element are reduced. In addition, since the switch element is enclosed within the holder by the nose piece, stock and rubber tube the possibility of corrosion of the switch element during cleaning is reduced; and a smooth, easily cleaned outer surface is provided. The stock and nose piece are preferably made of a heat resistant plastic which will withstand the temperatures encountered during autoclaving. Similarly, the rubber tube is preferably made of a material such as silicone rubber which will withstand these temperatures. In order to insure that the switch is hermetically sealed within the holder, a sealant such as an epoxy or silicone adhesive may be used at the interfaces between the nose piece and rubber tube and between the stock and rubber tube.

The electrical connection to metal pipe 12 is made through a conductive collet 30 which extends through and slides within the metal pipe. The front end of the collet is split into four outwardly bowed jaws 31 that are adapted to grip an electrode 32 inserted into the jaw. Ceramic or hard rubber insulation 33 may be provided on the electrode to reduce the chances that the surgeon will accidentally contact the electrode.

The rear end of collet 30 extends through a stepped bore 34 in stock 11. A release button 35 is screwed on the rear end of the collet. A spring 36 in the larger end of stepped bore 34 bears against the release button 35 and biases the collet towards the rear of the holder. This presses jaws 31 against a conical bearing surface 37 within the metal sleeve 21 attached to the front of pipe 12 and thereby compresses the jaws against the electrode.

Electrical connection to the collet is made through a spring contact 38 mounted in a stepped opening 39 that extends from the bottom of stock 11 through to the stepped bore 34 containing the collet. This opening is sealed and access to the electrical connections is provided by a cap 40 secured to stock 11 by a screw 41 that extends through a boss 42 in the cap 40 and into a boss 43 in the stock.

A generally U shaped lip 44, extending from the front of the cap to boss 42, slides into the larger portion of the stepped opening 39 in the stock. Sealant may be applied to the outer surfaces of lip 44 and/or the inside of stepped opening 39 to provide a better seal. The sealant should be a material which does not harden appreciably with age so that the cap may be removed to provide access to the electrical connections. The space enclosed by the cap is divided by an insulator 45, the edges of which rest on the annular shoulder 46 of stepped opening 39. The insulator separates spring contact 38 from the electrical connections to switch element 13, thereby reducing the chances of accidental short circuits. In addition, the insulator provides a water barrier that helps keep the electrical leads and connections and switch element 13 dry, which helps to prevent deterioration of these elements. Sealant may be provided between the insulator 45 and shoulder 46 to keep the space between the insulator and the cap as dry as possible. Again, a sealant which does not harden with age is preferred.

The spring contact 38, which is in sliding contact with collet rod 30, is mounted to stock 11 by a screw 47 which extends through insulator 45, through the spring contact 38, and into the annular shoulder 46. Spring contact 38 is mounted between the annular shoulder and the insulator. The end 48 of the spring contact extends around the insulator and the head of screw 47 into the space between the insulator and cap. This end may be bent up to provide access to screw 47 or bent down into the position shown in FIG. 2 to provide additional room for making electrical connections to the contact.

Electrical connection to the flexible strips 17 of the annular switch element 13 are made through a tab 49, best seen in FIG. 4, extending from the sheet that is bent to form the switch element. A wire 50 is attached to tab 49 and extends through a duct 51 through stock 11 that opens into the space between insulator 45 and cap 40.

The mating surfaces of the rear of cap 40 and stock 11 define a stepped bore 52 extending inwardly from the rear of the electrode holder. A flexible rubber collar 53 in bore 52 supports and seals a cable 54 which is connected to the electro-surgical generator (not shown). Two leads 55, 56 extend from cable 54 and run through grooves 57 around the boss 42 on the stock, which provides additional strain relief for the leads, and into the space between the cap 40 and insulator 45.

One of the leads 55, which is connected to the control circuit for the electro-surgical generator and to the radio frequency output terminal of the generator is connected to the wire 50 attached to the annular switch element 13. The other lead 56, which is connected to the control circuit only, is connected to spring contact 38. When one of the strips 17 of the switch element is depressed and contacts metal pipe 12, the control circuit is completed, the generator is activated and radio frequency current flows through lead 55, wire 50, switch element 13, pipe 12 and collet 21 to electrode 23.

As can be seen in FIG. 2, locating the electrical connections in the rear of the holder makes it possible to produce a holder with a relatively small front end. This makes it easier for the surgeon to grip and use the holder.

While we have described our invention in connection with a surgical electrode holder, our novel switch and collet may be used to advantage in a number of other hand tools. The foregoing description is merely illustrative and is not intended to limit the scope of this invention, which is defined by the appended claims.

Claims

We claim:

1. A normally open switch for a hand tool comprising:

a. an inner conductive member;

b. an annular switch element having a larger diameter than the inner conductive member and comprising:

i. a sheet having solid ends and slots extending between the ends that define flexible, resilient conductive strips extending between the ends, said sheet being formed from flat stock and curved into an annular shape; and

ii. retaining rings secured to each end of said sheet that maintain said annular shape; and

c. supports at both ends of the annular switch element which locate the switch element coaxial with and surrounding the inner conductive member, whereby the switch is closed by depressing at least one of the flexible conductive strips to make contact with the inner conductive member.

2. A normally open switch for a hand tool comprising:

a. an inner conductive member;

b. an annular switch element having a larger diameter than the inner conductive member and comprising a plurality of rings and a plurality of flexible, resilient conductive strips extending between the rings;

c. supports at both ends of the annular switch element which locate the switch element coaxial with and surrounding the inner conductive member, whereby the switch is closed by depressing at least one of the flexible conductive strips to make contact with the inner conductive member, at least one of said supports having a small end and a larger portion adjacent said small end, said annular switch element being slidably mounted on the small end of the support, with a gap between the annular switch element and the larger portion of the support;

d. one end of the inner conductive member being inserted in a stock and the other end of the inner conductive member having a nose piece attached thereto, said nose piece and said stock having a diameter greater than the diameter of the annular switch element, whereby the switch element is protected from damage and accidental closure by the stock and the nose piece; and

e. a flexible non-conductive tube surrounding the annular switch element and extending from the stock to the nose piece, said flexible tube being supported by the larger portion of the support, whereby the flexible tube does not prevent longitudinal movement of the switch element in said gap.

3. A surgical electrode holder comprising:

a. an inner conductive member;

b. an annular switch element having a larger diameter than the inner conductive member and comprising a plurality of rings and a plurality of flexible, resilient conductive strips extending between said rings, said strips having outwardly bowed central portions that are farther away from the inner conductive member than the ends of the conductive strips are;

c. supports at both ends of the annular switch element which locate the switch element coaxial to and surrounding the inner conductive member; and

d. means connecting the inner conductive member and the annular switch element to the control circuit of an electro-surgical generator, whereby said generator is activated by depressing at least one of said strips to make contact with the inner conductive member.

4. A surgical electrode holder according to claim 3 wherein the annular switch element is slidably mounted on at least one of said supports, whereby at least one end of the switch element is free to move longitudinally when the strips are depressed.

5. A surgical electrode holder comprising:

a. an inner conductive member;

b. an annular switch element having a larger diameter than the inner conductive member and comprising:

i. a sheet having solid ends and slots extending between said ends that define a plurality of flexible, resilient conductive strips extending between said ends, said sheet being formed from flat stock and curved into an annular shape; and

ii. retaining rings secured to each end of the sheet to maintain said annular shape;

c. supports at both ends of the annular switch element which locate the switch element coaxial to and surrounding the inner conductive member; and

d. means connecting the inner conductive member and the annular switch element to the control circuit of an electrosurgical generator, whereby said generator is activated by depressing at least one of said strips to make contact with the inner conductive member.

6. A surgical electrode holder comprising:

a. an inner conductive member;

b. an annular switch element having a larger diameter than the inner conductive member and comprising a plurality of rings and a plurality of flexible, resilient conductive strips extending between said rings;

c. supports at both ends of the annular switch element which locate the switch element coaxial to and surrounding the inner conductive member;

d. a stock behind the annular switch element and a nose piece in front of the switch element, said stock and said nose piece having a diameter larger than the annular switch element, whereby the switch element is protected by the stock and the nose piece; and

e. means connecting the inner conductive member and the annular switch element to the control circuit of an electrosurgical generator, whereby said generator is activated by depressing at least one of said strips to make contact with the inner conductive member.

7. A surgical electrode holder according to claim 6 further comprising a flexible non-conductive tube surrounding the annular switch element and extending from said stock to said nose piece.

8. A surgical electrode holder according to claim 7 wherein:

a. at least one of said supports has a small end and a larger portion adjacent said small end;

b. the annular switch element is slidably mounted on the small end of the support;

c. a gap is provided between the annular switch element and the larger portion of the support; and

d. said flexible tube is supported by the larger portion of the support, whereby the flexible tube does not prevent longitudinal movement of the switch element in said gap.

9. A surgical electrode holder comprising:

a. a hollow, conductive tube;

b. a conductive collet rod extending through and adapted to slide within said hollow tube, said collet rod having a front end split into a plurality of jaws adapted to grip a surgical electrode inserted therein and a rear end that extends through the hollow tube;

c. an annular switch element having a larger diameter than the hollow tube and comprising a plurality of rings and a plurality of flexible resilient conductive strips extending between said rings;

d. supports at both ends of the annular switch element which locate the switch element coaxial to and surrounding the hollow tube; and

e. means connecting the collet rod and the annular switch element to the control circuit of an electrosurgical generator, said hollow tube being connected to the control circuit through said collet rod, whereby said generator is activated by depressing at least one of said strips to make contact with the hollow tube.

10. A surgical electrode holder according to claim 9 wherein the electrical connection from the control circuit to the collet rod is made through a spring contact past which the rear end of the collet rod slides.

11. A surgical electrode holder according to claim 10 wherein:

a. said collet rod extends through a stock;

b. a cap is detachably mounted on said stock;

c. said cap and said stock define an electrical connection cavity in the holder at a location remote from the annular switch element; and

d. said spring contact is mounted in said cavity.

12. A surgical electrode holder according to claim 11 further comprising:

a. a duct extending through said stock to said electrical connection cavity; and

b. an electrical conductor attached to the annular switch element, and extending through said duct into said electrical connection cavity.

13. A combination normally open switch and gripping collet for a hand tool comprising:

a. a hollow conductive member;

b. an electrically conductive collet rod extending through and adapted to slide within the hollow conductive member, said collet having a front end that is divided into a plurality of jaws adapted to grip an object inserted into the jaws and a rear end that extends through the hollow conductive member;

c. an annular switch element comprising a plurality of flexible, resilient conductive strips adjacent to but normally displaced from the hollow conductive member; and

d. means for connecting the annular switch element and the conductive collet rod to an electrical circuit, whereby said electrical circuit is completed by depressing at least one of the flexible resilient conductive strips to make contact with the hollow conductive member.

14. A combination switch and collet according to claim 13 wherein the means for electrically connecting said electrical circuit to the collet rod comprises a spring contact past which the rear end of the collet slides.