JPH03280946A - Counter electrode plate for electric surgical knife - Google Patents

Abstract

PURPOSE:To simultaneously contrive improvement of capacitance and dielectric strength so as to contrive improvement of safety and characteristic by providing such constitution as interposing a conductive adhesive agent between an electrode sheet and an insulating dielectric film. CONSTITUTION:A capacitance type counter electrode plate is obtained by adhesively mounting an insulating dielectric film 7 through a conductive adhesive agent layer 6 under an electrode sheet 5 and further an exfoliation film 9 through an adhesive agent layer 8 under this insulating dielectric film 7. Since the conductive adhesive agent layer 6 is interposed thus between the electrode sheet 5 and the insulating dielectric film 7, capacitance is increased by determining a substantial distance of obtaining the capacitance not by a distance D between the electrode sheet 5 and a living body 13 but by a further short distance (d) between the conductive adhesive agent layer 6 and the living body 13. As a result, improvement of capacitance and dielectric strength can simultaneously be realized b) enabling thickness of the insulating dielectric film 7 to increase. The counter electrode plate is suited for a counter electrode plate for medical treatment by improving safety and characteristic according to the above.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a return electrode plate for an electric scalpel, particularly to a capacitive return electrode plate.

[Summary of the invention]

The present invention provides a counter electrode plate for an electric scalpel, which is used as a counter electrode of a scalpel tip electrode in an electric scalpel, and which has an electrode sheet and an insulating dielectric film, in which a conductive adhesive is interposed between the electrode sheet and the insulating dielectric film. By configuring this structure, it is possible to improve capacitance and withstand voltage at the same time.

[Conventional technology]

Generally, an electric scalpel converts electrical energy into thermal energy, and uses the thermal energy to perform incision and coagulation of living tissue.

Here, to briefly explain the principle of the electric scalpel, as shown in Figure 6, the electric scalpel body (3
1) and the living body (32) between the scalpel tip electrode (active electrode) (
33) and a return electrode plate (34).

The high frequency current i from the electric scalpel main body (31) flows from the scalpel tip electrode (33) to the living body (32), and circulates to the electric scalpel main body (31) through the return electrode (34). Incision or coagulation of living tissue occurs where the current density is high. That is, when a high frequency voltage is applied to the scalpel tip electrode (33), an arc discharge occurs between the scalpel tip electrode (33) and the living tissue, and if this arc discharge continues for several tens of microseconds, the temperature of the living tissue during the discharge increases to 100°C or more. The water in the cells evaporates rapidly and the living tissue is incised.

At this time, the current density is low near the incision layer, so the temperature rise is low and the living tissue is coagulated. In this way, by moving the scalpel tip electrode (33) while supplying the high frequency current l to the scalpel tip electrode (33), it is possible to provide an incision action accompanied by hemostasis due to coagulation action. Also,
When a high-frequency pulse current of about 10 μs is supplied to the living tissue at intervals of about 50 ALS, the temperature of the living tissue is suppressed to 100° C. or less, and the living tissue is not incised and only has a coagulating effect. In addition, when the pulse width of the high-frequency pulse current is set to several tens of microseconds, it is possible to create an incision (mixed incision) effect with strong hemostatic ability (ME equipment handbook I edited by Japan Electronics Machinery Industry Co., Ltd. P284-P28
5).

In such an electric scalpel, the return electrode plate (34) plays the role of safely returning the high frequency current flowing from the scalpel tip electrode (33) to the living tissue to the electric scalpel body (31).

In order to safely return the high frequency current l to the electric scalpel body (31), it is necessary to increase the contact area between the living body (32) and the return electrode (34) and reduce the current density. At present, a diameter of 15 square inches or more is usually used.

By the way, among various return electrodes, capacitance type return electrodes can be made to have a thin and soft structure, and have good adhesion to living organisms, so they are suitable for senior use as return electrodes. It tends to expand.

As shown in the schematic cross-sectional view of FIG. 7, a conventional capacitive return electrode plate includes a base material (41), an adhesive layer (42), an insulating film (43), an electrode sheet (44), and agent layer (45
), an insulating dielectric film (46), an adhesive layer (47), and a release film (48) are laminated in this order. When in use, peel off the release film (48) and attach the return electrode plate to a living body (indicated by a two-dot chain line) through the exposed adhesive layer (47).
32).

[Problem to be solved by the invention]

However, in the conventional return electrode, the electrode sheet (
Since the adhesive layer (45), the insulating dielectric film (46), and the adhesive layer (47) are interposed between the electrode sheet (44) and the living body (32), the distance between the electrode sheet (44) and the living body (32) is This has the disadvantage of increasing the capacitance of the return electrode and reducing the capacitance of the return electrode. Therefore, adhesive layers (45) and (47)
) could be considered to increase the capacitance by reducing the thickness of the capacitor, but this method has the disadvantage that the withstand voltage decreases and safety to the living body (32) cannot be ensured. others,
There is a method to increase capacitance by dispersing a ferroelectric material such as barium titanate in the adhesive layer (45), (47), but barium titanate is a material designated as a deleterious substance. , not suitable for use in the medical field.

The present invention has been made in view of these points, and an object of the present invention is to provide a return electrode plate for an electric scalpel that can improve capacitance and withstand voltage at the same time.

[Means to solve the problem]

The present invention provides a counter electrode plate (A) for an electric scalpel, which is used as a counter electrode of a scalpel tip electrode (23) in an electric scalpel and has an electrode sheet (5) and an insulating dielectric film [7].
A conductive adhesive (6) is interposed between an electrode sheet (5) and an insulating dielectric film (7).

[Effect]

According to the configuration of the present invention described above, since the conductive adhesive (6) is interposed between the electrode sheet (5) and the insulating dielectric film (7), the substantial distance for obtaining capacitance is between the electrode sheet and the insulating dielectric film (7). (
The capacitance is determined not by the distance between the conductive adhesive (6) and the living body (13), but by the shorter distance d between the conductive adhesive (6) and the living body (13). As a result, it is possible to increase the thickness of the insulating dielectric film (7), and it is possible to simultaneously improve capacitance and withstand voltage. Along with this, the safety and properties are further improved, making it suitable as a medical return electrode.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1 to 5.

FIG. 1 is an exploded perspective view showing the structure of a capacitive return electrode plate (A) for an electric scalpel according to this embodiment, and FIG. 2 is a cross-sectional view thereof.
FIG. 3 is a schematic enlarged sectional view thereof.

As shown in the figure, this return electrode plate (A) includes a base material (1), an adhesive layer (2), an insulating film (3), an adhesive layer (4), an electrode sheet (5), a conductive adhesive layer ( 6), an insulating dielectric film (7), an adhesive layer (8) and a release film (9) are sequentially laminated.The insulating film (3), adhesive layer (4), electrode sheet (5) and The conductive adhesive layer (6) is the other member (1).

It is formed one size smaller than (2), (7), (8) and (9).

Two through holes (li), (2h), (3h) were provided at each end from the base material (1) to the electrode sheet (5).
), (4h), 2 rivets in (5h)) (10
a) and (10b) respectively, and insert them into the two rings (lla) and (llb) located below the through hole (5h) of the electrode sheet (5), and further these rivets) (10a ), (10b) are caulked. Each ring (lla) and (llb) is connected to the electric scalpel body (not shown) via conductor wires (12a) and (12b), respectively, so this rivet
By caulking (10a) and (10b), the electric scalpel main body and the electrode sheet (5) are electrically connected. Then, an insulating dielectric film (7) is bonded under the electrode sheet (5) via a conductive adhesive layer (6), and then peeled off via an adhesive layer [8] under this insulating dielectric film (7). A capacitive return electrode (A) according to this example is obtained by adhering the film (9).

In addition, in this example, rivets (10a), (10b)
For the rings (lla) and (llb), those with sparrows are used. In addition, a conducting wire (12a),
In principle, only one wire (12b) is required, but in this example, the conductor (12a), (12b) itself and the electrode sheet (5) are checked for disconnection, and the base material [1] and the insulating film (3) are checked for disconnection. Two conductive wires (12a) and (12b) are used to check for mechanical damage such as. That is, to check for disconnections, etc., check the conductors (12a) and (12b).
This is done by connecting both the positive and negative poles to the terminals, passing a current through one conductor (12a), and confirming that the current flows back to the other conductor (12b). On the other hand, when using it as a return electrode for an electric scalpel, use a release film (9
) and attach the return electrode (
A> is a living body (indicated by a two-dot chain line in Fig. 3) (13)
and connect the same polarity to the conductors (12a) and (12b) respectively.

As the conductive material for the conductive adhesive layer (6), for example, metal powder or fiber such as carbon, Ni, Au, Ag, Cu, solder, or metal-coated resin powder is used. Moreover, the thickness t of the conductive adhesive layer (6)
is 5 to 100 μm, preferably 10 to 40 μm, and the conduction resistance in the thickness direction in the effective use area is 100 μm.
The resistance should be Ω or less, preferably 10Ω or less. still,
The conductive material may be used alone or in combination of two or more kinds.

Here, the adhesive layers (2) and (8) used in this example
And a method for producing the conductive adhesive layer (6) will be explained.

First, 2 ethylhexyl acrylate 60g 1 ethyl acrylate 35g 1 glycidyl methacrylate 5F! ,
0.7g of azobisisobutylnitrile to 10g of ethyl acetate
0 g, reacted in a nitrogen stream at about 70° C. for 10 hours, and further diluted by adding 133 g of toluene to obtain an acrylic copolymer solution. Next, 2 g of a crosslinking agent was added to 100 g of the acrylic copolymer solution and mixed uniformly to form an adhesive layer (2) according to this example.

(8) is obtained. The conductive adhesive layer (6) is obtained by adding 3 g of carbon black to 100 g of the adhesive obtained by the above-mentioned manufacturing method and uniformly mixing the mixture.

Next, withstand voltage experiments for the above examples and capacitance values obtained in the experiments will be explained based on the table below.

In this withstand voltage experiment, 3
A high voltage of kV was applied for 5 minutes, and the time until dielectric breakdown and the capacitance value at that time were investigated, and each test was repeated three times.

Here, the examples include a base material (1), an adhesive layer (2), an insulating film (3), an adhesive layer (4), an electrode sheet (5),
The thicknesses of the conductive adhesive layer (6), the insulating dielectric film (7), and the adhesive layer (8) are 1.0 mm and 12 μm, respectively.
25μm, 3μm, 12μm.

Comparative example 1: 12 μm, 38 μm, 12 μm
Of the above examples, the insulating dielectric film (7) had a thickness of 25 μm and the adhesive layer (8) had a thickness of 25 μ0. Comparative Example 2 used the conventional product shown in FIG. .

As can be seen from the experimental results shown in the above table, in the case of the example, no dielectric breakdown occurred in the three withstanding voltage experiments, and the capacitance value was 7 nF or more, which is preferable for a counter electrode. On the other hand, in Comparative Example 1, although an increase in the capacitance value was observed,
Dielectric breakdown occurs in 10 to 15 seconds and it cannot be used as a return electrode. In Comparative Example 2, the time until dielectric breakdown is longer than in Comparative Example 1, but it is about 3 to 4 minutes;
The capacitance value is also less than 7nF.

As described above, according to this example, since the conductive adhesive layer (6) is interposed between the electrode sheet (5) and the insulating dielectric film (7), the substantial distance for obtaining capacitance is , the capacitance is determined not by the distance between the electrode sheet (5) and the living body (13) but by the shorter distance d between the conductive adhesive (6) and the living body (13), which increases the capacitance. As a result, it is possible to increase the thickness of the insulating dielectric film (7), and improve capacitance and withstand voltage at the same time.As a result, safety and characteristics are improved, making it suitable for medical use. This makes it suitable as a counter electrode plate.

Incidentally, in actual surgery using an electric scalpel, as shown in FIG. 4, an electric scalpel main body (21) and an electrocardiogram monitor (22) are used together. In addition, (23) is a scalpel tip electrode. In this actual surgery using an electric scalpel, if the contact between the return electrode (A) and the living body (13) is poor, the diffusion effect of the current density by the return electrode (A) will be poor and current will flow locally. There is a problem in that burns occur in areas where the current flow is concentrated. In addition, the high-frequency current i from the scalpel tip electrode (23) flows through the electrode (24) of the electrocardiogram monitor (22) attached to the limbs of the living body (13), causing burns at the attachment site of the electrode (24). There is also the problem of causing

Therefore, in this example, as shown in FIG.
5) is divided into two parts, an outer part (5a) and an inner part (5b), each of which takes a return path for high-frequency current independently. At this time, the outer part (
5a) and the area of the inner part (5b) are respectively Sl and S2
, each return current is 1. and 1. Then, the total current I.

is the following formula % formula % Also, each return current i and 12 are determined by the following formula and the above formula (
From 1) and (2), calculate the calculated values for each return current ll and 120 current amount and ratio, and quickly find out the contact state of the return electrode <A> with the living body (13) from the calculated values and actual measured values. be able to.

According to this example, it is used as a return electrode for an electric scalpel.

Therefore, since the state of contact with the living body (13) can be monitored at the same time, safety can be further improved.

〔Effect of the invention〕

According to the return electrode plate for an electric scalpel of the present invention, it is possible to simultaneously improve capacitance and withstand voltage, as well as improve safety and characteristics, making it suitable as a medical return electrode plate. Become.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing the structure of a capacitive return electrode plate for an electric scalpel according to this embodiment, Fig. 2 is a sectional view thereof, Fig. 3 is a schematic enlarged sectional view thereof, and Fig. 4 is an electrical An explanatory diagram showing how the scalpel is used, Fig. 5 is a plan view showing the configuration of an electrode sheet according to another embodiment, Fig. 6 is an explanatory diagram showing the principle of the electric scalpel, and Fig. j@7 shows a conventional example. It is a schematic cross-sectional view. (A) is a return electrode, [1] is a base material, (2) is an adhesive layer,
(3) is an insulating film, (4) is an adhesive layer, (5) is an electrode sheet, (6) is a conductive adhesive layer, (7) is an insulating dielectric film, (8) is an adhesive layer, (9 ) is a release film. Agent: Hide Matsukuma (T% female/) Explanatory diagram showing the shape of the eyebrows in Fig. 4) = Sheet (Plane showing the 11 smoldering electrodes)

Claims (1)

[Scope of Claims] A counter electrode plate for an electric scalpel, which is used as a counter electrode of a scalpel tip electrode in an electric scalpel and has an electrode sheet and an insulating dielectric film, wherein a conductive adhesive is used between the electrode sheet and the insulating dielectric film. A return electrode plate for an electric scalpel with a