JP2010227462A - Electrode for medical device and medical treatment instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for medical devices and a medical treatment instrument which are used at a low voltage and suppress a deterioration of treatment performance due to adhesion of living tissues. <P>SOLUTION: A high-frequency treatment instrument 10 includes an electrode part 1 used by abutting on a subject to be treated. The electrode part 1 includes an electrode body 2 constituted of a metallic material and a coating layer 3 formed on a surface of the electrode body 2. A group of materials showing thermal oxidation resistance higher than that of the metallic material of the electrode body 2 belong to a first group. A group of materials showing electrochemical oxidation resistance higher than that of the metallic material of the electrode body 2 belong to a second group. A group of materials having a water contact angle greater than that of the metallic material of the electrode body 2 belong to a third group. The coating layer 3 is formed by mixing two or more kinds of materials including one or more kinds of low stickiness materials constituted of one or more kinds of materials belonging to one or more groups among the first, second, and third groups and one or more kinds of conductive materials with electric conductivity higher than that of the metallic material of the electrode body 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrode for a medical device and a medical treatment tool.

2. Description of the Related Art Conventionally, for example, a high-frequency treatment tool that incises or coagulates a living tissue by applying a high-frequency voltage to the living tissue that is an object to be treated is known. In such a high-frequency treatment tool, an electrode for medical equipment that applies a high-frequency voltage in a state of being in contact with a living tissue is used.
In such electrodes for medical devices, the impedance and discharge characteristics of the electrode change due to the biological tissue adhering to the electrode surface during treatment of the biological tissue, and the treatment performance such as sharpness and coagulation performance deteriorates. Therefore, there has been a strong demand for an electrode for medical equipment in which living tissue is difficult to adhere to the electrode surface.
As such a technique, conventionally, it is known to provide a coat layer for reducing adhesion of a living tissue on the surface of an electrode body.
For example, in Patent Document 1, a high-frequency electrode is disposed at the distal end of an electrically insulating sheath that is inserted into and removed from a treatment instrument insertion channel of an endoscope so as to contact the living body and cauterize the contact surface of the living body. An endoscopic high-frequency treatment instrument (medical treatment instrument), wherein a coating made of a metal or an alloy of gold or white metal is formed on a part or all of the high-frequency electrode. The ingredients are listed.
Here, the coating formed on a part of the high-frequency electrode covers at least the electrode surface in a range that is a contact surface with the living body.
Patent Document 2 discloses a bipolar tweezers (medical treatment tool) having a pair of sandwiching portions and having a function of applying high-frequency power to a sandwiched body sandwiched by the pair of sandwiching portions. A bipolar tweezers is described in which the surface of an electrode (medical device electrode) in a clamping part is mirror-finished and a film for preventing scratches is formed on the surface of the electrode.
The film for preventing damage of the bipolar tweezers is made of a titanium nitride film.

JP 2006-68407 A JP 2000-107194 A

However, the conventional medical device electrode and medical treatment tool as described above have the following problems.
In the technique described in Patent Document 1, since the coating on the electrode surface is made of gold, a white metal, or an alloy thereof, it is considered that the living tissue is difficult to be fixed. Since the hardness is lower than that of steel or the like, the electrode surface is easily scratched. When scratches occur on the electrode surface and fine irregularities are formed on the surface, when high-frequency voltage is applied, discharge concentrates on the projections of the irregularities. Heat generation at the part becomes remarkable. Therefore, there is a problem that the living tissue is rapidly dried and solidified, and the living tissue is easily fixed on the electrode surface, and the treatment performance is deteriorated.
In the technique described in Patent Document 2, since a titanium nitride film is formed on the surface of the electrode, the hardness of the surface can be improved compared to stainless steel and the like, and the living body due to the generation of scratches on the surface of the electrode. Although the adhesion of the tissue can be reduced, the surface of the electrode is covered with an insulator. As a result, the impedance becomes larger than that of the conductor electrode, and it is necessary to apply a higher voltage. When the voltage increases in this way, there is a problem that operability as a medical treatment instrument used for a human body is deteriorated.

  The present invention has been made in view of the above problems, and can be used at a low voltage, and can be used for medical device electrodes and medical treatment tools that can suppress deterioration of treatment performance due to fixation of biological tissue. The purpose is to provide.

In order to solve the above-mentioned problems, the medical device electrode of the present invention is a medical device electrode used in contact with an object to be treated, the electrode main body made of a metal material, and the surface of the electrode main body The coating layer is formed of a first group of materials having higher heat-resistant oxidation characteristics than the metal material of the electrode body, and more electrochemical oxidation resistance than the metal material of the electrode body. When the material group having a higher contact angle with water than the metal material of the electrode body is referred to as the third group, the first group, the second group, and the third group. Two or more types each including one or more types of low-adhesion materials comprising at least one type included in any one group or more and one or more types of conductive materials having higher electrical conductivity than the metal material of the electrode body The material is mixed.
According to the present invention, the coating layer formed on the surface of the electrode body is composed of one or more kinds of low-adhesion materials and electrodes included in one or more of the first group, the second group, and the third group. Since two or more types of materials each including one or more types of conductive materials having a higher electrical conductivity than the main body are mixed, it is possible to suppress the fixation of the living tissue on the electrode surface by the low adhesion material, Good impedance can be ensured by the conductive material.
Since the first group is a group of materials having higher heat-resistant oxidation characteristics than the metal material of the electrode body, the coat layer is less likely to be thermally oxidized than the electrode body even if the temperature rises. For this reason, the surface of the coat layer is thermally oxidized, so that no fine irregularities on the surface are generated, and there is no change in the concentration of current distribution due to the generation of oxides, thereby suppressing the cause of adherence of living tissue. .
The second group is a group of materials having higher electrochemical oxidation resistance than the metal material of the electrode body, so that the surface of the coat layer is not oxidized, and fine surface irregularities are not generated. Since there is no change such as concentration of current distribution due to generation, the cause of sticking of living tissue is suppressed.
The third group is a group of materials having a contact angle with water larger than that of the metal material of the electrode body, so that the living tissue is less likely to adhere to the surface of the coat layer, and the cause of the sticking of the living tissue is suppressed.

  In the medical device electrode of the present invention, the electrode body is made of stainless steel, and the low-adhesion material is included in the first group, such as high hardness DLC (diamond-like carbon), titanium carbonitride (TiCN). ), Titanium nitride (TiN), chromium nitride (CrN), and titanium aluminum nitride (TiAlN).

  In the medical device electrode according to the present invention, the electrode body is made of stainless steel, and the low-adhesion material is silver (Ag), platinum (Pt), and gold (Au) included in the second group. It is preferable to include any one or more of the above.

  In the medical device electrode of the present invention, the electrode body is made of stainless steel, and the low-adhesion material is a fluorine-containing DLC, a silicone-based resin, or a fluorine-based resin included in the third group. It is preferable that any one or more of these are included.

  In the medical device electrode of the present invention, the electrode body is made of stainless steel, and the conductive material is made of copper (Cu), gold (Au), aluminum (Al), platinum (Pt), and chromium ( Preferably, one or more of (Cr) are included.

The medical treatment instrument of the present invention includes the medical device electrode of the present invention.
According to this invention, since the medical device electrode of the present invention is provided, the same operation as the medical device electrode of the present invention is provided.

  According to the medical device electrode and the medical treatment instrument of the present invention, the low adhesion having lower adhesion than the electrode body in at least one of the heat oxidation resistance, electrochemical oxidation resistance, and contact angle with water. Since a coating layer containing an adhesive material and a conductive material having a higher electrical conductivity than the electrode body is formed on the surface of the electrode body, it can be used at a low voltage and suppresses deterioration of treatment performance due to adhesion of living tissue. There is an effect that can be done.

It is a typical block diagram which shows schematic structure of the medical treatment tool provided with the electrode for medical devices which concerns on embodiment of this invention. It is AA sectional drawing in FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
A medical device electrode and a medical treatment tool according to an embodiment of the present invention will be described.
FIG. 1 is a schematic configuration diagram showing a schematic configuration of a medical treatment instrument including a medical device electrode according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG.

  The high-frequency treatment tool 10 of this embodiment is a medical treatment tool for incising and excising a living tissue as a treatment object or coagulating (hemostasis) the living tissue by applying a high-frequency voltage. As shown in FIG. 1, the schematic configuration of the high-frequency treatment instrument 10 includes a grasping portion 4 for an operator to hold by hand, and an electrode portion 1 protruding from the distal end of the grasping portion 4.

The electrode unit 1 is an electrode for medical equipment that applies a high-frequency voltage by contacting a living tissue as a treatment object, and is provided on a shaft portion 2a connected to a high-frequency power source 5 and a distal end side of the shaft portion 2a. The electrode body 2 has a spatula-like treatment portion 2b, and the coat layer 3 is formed on the surface of the shaft portion 2a.
As the material of the electrode body 2, an appropriate metal material can be adopted. In this embodiment, as an example, stainless steel excellent in strength and corrosion resistance, for example, SUS304 is employed.
The thermal oxidation start temperature To of SUS304 is about 500 ° C., the contact angle with water is about 80 °, and the electrical conductivity σ is σ = 1.4 × 10 ¹⁶ (1 / Ω · m)). is there.
SUS304 is an iron-based alloy containing iron (Fe) as a main component and containing nickel (Ni) and Cr. The standard electrode potentials Es of Fe, Ni, and Cr are -0.447 (V), respectively. , −0.257 (V), −0.744 (V), both of which take negative values, the standard electrode potential Es is more easily oxidized than a positive metal material.

The coat layer 3 covers the outer surface of the treatment portion 2b of the electrode body 2 with a substantially constant layer thickness. The coat layer 3 has a low adhesion material having a lower adhesion to living tissue than the metal material of the electrode body 2, and an electrode The film is formed by mixing two or more kinds of materials each including one or more kinds of conductive materials having higher electrical conductivity than the metal material of the main body 2. Here, mixing means that a low adhesion material and a conductive material are mixed at least on the surface of the coat layer 3.
Further, the low-adhesion material for living tissue refers to a material group (hereinafter referred to as a first group) having higher heat-resistant oxidation characteristics than the metal material of the electrode body 2, and more electrochemical acid resistance than the metal material of the electrode body 2. Included in any one or more of a material group (hereinafter referred to as the second group) having high chemical properties and a material group (hereinafter referred to as the third group) having a larger contact angle with water than the metal material of the electrode body 2 Means one or more materials.
Thereby, as shown in FIG. 2, the treatment portion 2 b is covered with the coat layer 3 on both the front and back surfaces in the thickness direction.
The layer thickness of the coat layer 3 may be an appropriate layer thickness depending on the required surface hardness and conductivity, but is preferably 0.5 μm to 30 μm, for example. When the layer thickness is less than 0.5 μm, the surface roughness due to normal machining (cutting, grinding, etc.) cannot be covered by the coat layer 3, and the base material of the treatment portion 2b is exposed. On the other hand, if the layer thickness exceeds 30 μm, the possibility of cracking due to internal stress of the coat layer 3 increases. The layer thickness of the coat layer 3 is more preferably 4 μm to 10 μm. By setting the layer thickness to 4 μm or more, it becomes possible to prevent the substrate from being exposed even in parts obtained by processing that increases the surface roughness, such as forging, etc. Can also be covered. In addition, by setting the layer thickness to 10 μm or less, it becomes possible to prevent the coating layer 3 from being cracked or peeled off due to a difference in thermal expansion coefficient between the base material of the treatment portion 2 b and the coating layer 3 due to heating or cooling.
Further, the number of types of the low-adhesion material and the conductive material is not particularly limited as long as one or more types are included, and two or more types of materials are included.
Moreover, as long as the low adherence of the electrode part 1 to the living tissue and the impedance can be kept good, the adherence to the living tissue and the electrical conductivity σ may include a material that becomes the electrode body 2 or less.
The impedance of the electrode part 1 is preferably 0.1Ω or more and 1000Ω or less.

  The thermal oxidation characteristics of the first group of low adhesion materials are determined by the thermal oxidation start temperature To of the material. Therefore, when the electrode body 2 is made of stainless steel as in the present embodiment, high hardness DLC (trade name: HA • DLC, manufactured by Japan IT-F Co., Ltd., To = about 550 (° C.)), TiCN (To = about 520 (° C.)), TiN (To = about 600 (° C.)), CrN (To = about 800 (° C.)), and TiAlN (To = about 900 (° C.)) Including materials can be employed.

The electrochemical oxidation resistance of the second group of low adhesion materials shall be determined by the standard electrode potential Es or by experiment. As in the present embodiment, when the electrode body 2 is made of stainless steel, a material having a positive standard electrode potential Es can be preferably used. For example, a material containing one or more of Ag (Es = + 0.8 (V)), Pt (Es = + 1.11 (V)), and Au (Es = + 1.50 (V)) is used. Can be adopted.
In the case where the electrode body 2 is made of a metal element, a metal material having a value larger than the standard electrode potential Es of the metal element of the electrode body 2 can be adopted as the second group of low adhesion materials. In this case, the standard electrode potential Es may be negative.
Moreover, the magnitude of electrochemical oxidation resistance between alloys can be determined by experiment.

As an example of the low adhesion material of the third group, when the electrode body 2 is made of stainless steel as in this embodiment, any one or more of fluorine-containing DLC, silicone resin, and fluorine resin is used. The material containing can be adopted.
For example, the contact angle with water is about 96 ° in a fluorine-added DLC (manufactured by Japan ITF Co., Ltd.) which is an example of a fluorine-containing DLC. Further, CYTOP resin (manufactured by Asahi Glass Co., Ltd.), which is an example of a fluorine-based resin, has an angle of approximately 118 °, and Nanoscoat (manufactured by T & K Corp.) has an angle of approximately 124 °.

As an example of the conductive material, when the electrode body 2 is made of stainless steel as in this embodiment, Cu (σ = 59 × 10 ¹⁶ (1 / Ω · m)), Au (σ = 45. 2 × 10 ¹⁶ (1 / Ω · m)), Al (σ = 37 × 10 ¹⁶ (1 / Ω · m)), Pt (σ = 9.4 × 10 ¹⁶ (1 / Ω · m)), and A material containing one or more of Cr (σ = 7.5 × 10 ¹⁶ (1 / Ω · m)) can be used. Here, the electric conductivity showed a value of 25 ° C.

In the present embodiment, since the coating layer 3 includes two or more types of materials each including one or more types of low-adhesion materials and conductive materials, various characteristics of the coating layer 3 can be adjusted. For example, since Au has low adhesion and good conductivity, it is conventionally known that only an Au film is formed on the electrode body. However, since Au has low hardness, the surface is easily scratched, When fine scratches are made on the surface, the discharge from the convex portions of the scratches becomes large, and the living tissue is locally heated, which tends to cause sticking to the convex portions of the scratches.
Therefore, when adopting Au as either one of the low-adhesion material and the conductive material, it is preferable to adopt a material having higher hardness than Au as the other of the low-adhesion material and the conductive material. .
And the hardness of the coat layer 3 as a whole is improved by adjusting the degree of dispersion so that the adjacent distance between the higher hardness material exposed on the surface of the coat layer 3 and Au becomes sufficiently small. , Au can be made hard to be damaged. Thereby, adherence of the living tissue can be stably suppressed. For example, by adopting a combination of Au and TiN or a combination of Au and Cr, the low adhesion can be further stabilized.

  Such a coat layer 3 can be formed by sputtering, ion plating or the like PVD method, heat or plasma, CVD method by laser, plating or the like, which targets a low adhesion material and a conductive material. It is not particularly limited. Moreover, the mixing ratio of each material can be adjusted by changing the film formation rate ratio of each material or the amount of reactive gas introduced.

The operation of the high-frequency treatment instrument 10 having such a configuration will be described.
The high-frequency treatment instrument 10 applies a high-frequency voltage to the electrode portion 1 of the high-frequency treatment instrument 10 by the high-frequency power source 5 with the counter electrode 6 attached to the patient, and the operator applies the electrode portion 1 to the treatment target portion of the patient. Of these, the portion corresponding to the treatment portion 2b covered with the coat layer 3 is used in contact.
At this time, a high-frequency current is generated between the electrode portion 1 and the counter electrode plate 6 via the coat layer 3, but the contact portion between the electrode portion 1 and the living tissue is extremely small compared to the electrode area of the counter electrode plate 6. Because of the area, the current density becomes extremely large only in the vicinity of the contact portion between the electrode portion 1 and the living tissue, and Joule heat is generated. At this time, if the temperature rise is moderate, the tissue is dried and denatured due to the evaporation of moisture, and the tissue is solidified. When the temperature rise is rapid, the carbonization of the tissue is likely to proceed, and the tissue is easily fixed to the electrode portion 1.

At this time, if the surface of the electrode unit 1 that comes into contact with the living tissue is made of a material having high adhesion to the living tissue, the living tissue is fixed to the surface of the electrode unit 1. Thereby, the discharge characteristic of the surface of the electrode part 1 changes, and the treatment performance, for example, sharpness etc. of the high frequency treatment tool 10 deteriorates.
In the electrode unit 1 of the present embodiment, when the coat layer 3 provided on the surface of the treatment unit 2b includes a low-adhesion material, the electrode body 2 having higher adhesion to living tissue is exposed on the surface. In comparison with this, it is possible to suppress adherence of living tissue.
Thereby, degradation of treatment performance due to fixation of living tissue can be suppressed.

The adhesion to the living tissue can be evaluated from various viewpoints. In this embodiment, the adhesion is increased by oxidizing the surface of the electrode unit 1, and the living tissue with moisture is the electrode unit. In view of the fact that the adhesiveness is increased because it easily adheres to the surface of 1, a low adhesiveness material is selected.
Since the first group of low-adhesion materials have higher heat-resistant oxidation characteristics than the metal material of the electrode body 2, even when the temperature of the electrode unit 1 rises during use of the high-frequency treatment instrument 10, thermal oxidation of the surface hardly occurs. In addition, since the smoothness of the surface is kept good, it is possible to suppress the adherence of the living tissue.
The second group of low-adhesion materials have a higher electrochemical oxidation resistance than the metal material of the electrode body 2 and are therefore substances that are less likely to oxidize than the metal material of the electrode body 2. As a result, thermal oxidation of the surface is unlikely to occur and the smoothness of the surface is kept good, so that sticking of living tissue can be suppressed.
Since the third group of low-adhesion materials have a larger contact angle with water than the metal material of the electrode body 2, the adhesive force to the surface of the electrode portion 1 of the biological tissue containing moisture is small. Therefore, incision or the like is performed in a state where the area of attachment to the surface of the electrode unit 1 is small, and thus it is possible to suppress adherence of living tissue.

On the other hand, when a film made of only a low-adhesive material with low conductivity is formed on the treatment portion 2b, the impedance of the electrode portion 1 increases, and the power of the high-frequency power source 5 must be increased. Since a conductive material is mixed in 3, impedance can be set satisfactorily.
For example, if the impedance of the electrode unit 1 is set to be as low as 0.1Ω or more and 1000Ω or less, the power of the high frequency power supply 5 can be suppressed.
For example, the impedance of a conventional electrode coated with an organic material such as PTFE or silicone resin is 200 to 400 kΩ. When the tissue is coagulated with such an electrode, a power supply of about 80 W is required in the coagulation mode. However, by setting the impedance of the electrode unit 1 to 0.1Ω to 1 kΩ as in the present invention, the same treatment can be performed with a power of about 20 W.
For this reason, compared with the high frequency treatment tool which requires more electric power, handling of the high frequency treatment tool 10 becomes easy, and operativity improves. In addition, the size of the high-frequency power source 5 can be reduced.

  In the above description, an example in which the medical device electrode is used in a high-frequency treatment tool that is an example of a medical treatment tool has been described. However, the medical treatment tool is not limited to a high-frequency treatment tool. For example, any shape such as a probe, forceps, tweezers, scalpel, snare, and wire can be used, and any of bipolar and monopolar can be applied.

1 Electrode part (Electrode for medical equipment)
2 Electrode body 2b Treatment section 3 Coat layer 5 High frequency power supply 10 High frequency treatment instrument (medical treatment instrument)

Claims (6)

A medical device electrode used in contact with an object to be treated,
An electrode body made of a metal material;
A coating layer formed on the surface of the electrode body,
The coat layer is
A first group of materials having higher thermal oxidation resistance than the metal material of the electrode body, a second group of materials having higher electrochemical oxidation resistance than the metal material of the electrode body, and a metal material of the electrode body When the group of materials having a larger contact angle with water is referred to as the third group,
A low-adhesion material composed of one or more types included in any one or more of the first group, the second group, and the third group;
An electrode for a medical device, wherein two or more kinds of materials each including one or more kinds of conductive materials having higher electrical conductivity than the metal material of the electrode body are mixed. The electrode body is made of stainless steel,
The low adhesion material includes high hardness DLC (diamond-like carbon), titanium carbonitride (TiCN), titanium nitride (TiN), chromium nitride (CrN), and titanium aluminum nitride (TiAlN) included in the first group. The medical device electrode according to claim 1, comprising at least one of the above. The electrode body is made of stainless steel,
3. The low adhesion material includes one or more of silver (Ag), platinum (Pt), and gold (Au) included in the second group. The electrode for medical devices described in 1. The electrode body is made of stainless steel,
3. The conductive material according to claim 1, wherein the conductive material includes one or more of copper (Cu), gold (Au), aluminum (Al), platinum (Pt), and chromium (Cr). The electrode for medical equipment as described. The electrode body is made of stainless steel,
The low adhesion material includes any one or more of fluorine-containing DLC, silicone resin, and fluorine resin included in the third group. The electrode for medical devices described in 1.   A medical treatment instrument comprising the medical device electrode according to claim 1.

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