JPH09135906A - Sensor for intra-corporeal medical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and cheap sensor for an intra-corporeal medical instrument having a simple structure which can certainly sense a pressure applied to the end of the instrument. SOLUTION: This sensor 3 is attached to the tip of an intra-corporeal medical instrument 1 such as a catheter and performs a sensing operation at the position. A resilient resin member 4 constructing the sensor 3 includes a conductive substance and electrodes 5a, 5b, 6a, and 6b are arranged at a plurality of positions in the resilient resin member 4 so as to be apart from each other. Pairs among the electrodes 5a, 5b, 6a, and 6b, that is, 5a-5b and 6a-6b are arranged so as to be along an axial line C1 of the resilient resin member 4. Consequently, the degree of deformation of the resilient resin member 4 is sensed on the basis of a change in value of resistance between the electrodes 5a-5b and between the electrodes 6a-6b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for an internal medical instrument.

[0002]

2. Description of the Related Art For example, endoscopes and catheters have been conventionally known as medical instruments which are inserted into various kinds of pipes inside a human body and perform a medical treatment there. This kind of device usually comprises a thin guide tube to be inserted into the body and an operating means provided at the proximal end of the guide tube for operating the guide tube outside the body. Further, in the guide tube, a mechanism necessary for each medical device, for example, a medication tube or an air supply tube for balloon expansion in a medical catheter, and an optical fiber as a light transmission means in an endoscope are housed. ing.

For example, an operator who uses an endoscope needs to push the guide tube forward while operating the tip of the guide tube by operating means so as to surely reach the target portion. However, the tube in the body is not always straight, and it is often the case that it is partially bent or branched. Therefore, an operator with low skill may guide the tip to a site that is not the desired site.

On the other hand, an operator with a high degree of skill predicts the presence of a bent portion and the like by recognizing the increase in the insertion resistance of the guide tube by the sense of his / her own hand, and determines the traveling direction accordingly. However, even an operator with a high degree of skill depends on the operation, and therefore cannot always guide the user to the intended place.

As a measure for solving the above problems, for example, some kind of sensor is provided at the tip of the guide tube, and the magnitude of the pressure received by the contact with the inner wall of the tube is
It is believed to measure direction with the sensor. Also,
As an example of embodying such an idea, Japanese Patent Laid-Open No. 6-190
There is a technique disclosed in Japanese Patent Publication No. 050.

In the medical device of this publication, a tactile sensor is attached to the tip of the guide tube. This tactile sensor is configured by disposing a strain gauge for detecting pressure near the tip edge of the soft tube. More specifically, a plurality of beams and slits are formed in the tip edge of the soft tube, and a strain gauge is mainly arranged in the beam portion. Therefore, when the sensor contacts the inner wall of the tube, the beam is elastically deformed by the external force. At this time, the strain gauge converts the distortion of the beam into electrical impedance and outputs it to the outside. As a result, the magnitude and direction of the pressure applied to the distal end of the guide tube is detected, and the convenience for determining the traveling direction when the operator operates is designed.

Also, instead of such a tactile sensor,
It has been conventionally proposed to provide a semiconductor pressure sensor having a diaphragm as a pressure detection unit. Note that this type of sensor has an advantage that it is suitable for downsizing as a whole.

[0008]

However, the above-mentioned sensor for a medical instrument inserted into the body has the following problems.

I) In the case of a tactile sensor using a strain gauge, since it is necessary to form a fine beam, a slit and a strain gauge on the tip edge of the sensor, the structure is inevitably complicated and its manufacture is difficult. Also,
With such a configuration, miniaturization of the sensor may be hindered.

Ii) In recent years, medical instruments that can be inserted into the body (to be exact, guide tubes, sensors, etc. that are inserted portions) have been
In order to prevent secondary infection of viruses such as DS, it is becoming common practice to dispose of it. Therefore, it is preferable that the sensor used therefor be inexpensive.
However, since the semiconductor pressure sensor is expensive at present, it cannot be said that this condition is satisfied. Further, since the tactile sensor using the strain gauge has the difficulty in manufacturing as described above, it is inevitable that the tactile sensor becomes expensive to some extent. Therefore, it cannot be said that the sensor also satisfies the above conditions.

The present invention has been made in view of the above problems, and its main purpose is not only to be able to reliably detect the pressure applied to the tip of an instrument, but also to have a simple structure, which is small and inexpensive. Another object of the present invention is to provide a sensor for a medical instrument that can be inserted into the body.

[0012] Another object of the present invention is to provide a sensor for an implantable medical device which is highly compatible with the living body.

[0013]

In order to solve the above-mentioned problems, the invention according to claim 1 is a sensor which is attached to the distal end of an internal-insertion-type medical instrument and which performs sensing at that position, Electrodes inserted at a plurality of locations in an elastic resin member containing a conductive substance are separated from each other, and the degree of deformation of the elastic resin member is detected based on a change in resistance value between the electrodes. The gist is a sensor for a medical device.

According to a second aspect of the present invention, in the first aspect, the elastic resin member is hollow. According to a third aspect of the present invention, in the second aspect, the elastic resin member is a tubular body, and the plurality of electrodes are arranged on an inner peripheral surface of the tubular body.

The invention according to a fourth aspect is the first to the third aspects.
In any one of the above items, one pair of the plurality of electrodes is arranged so as to be aligned along the axial direction of the elastic resin member.

The invention according to claim 5 is the same as claims 1 to 3.
In any one of the above items, the plurality of electrodes are two pairs, and one of them is arranged so as to form an angle of 90 ° with another pair with respect to the axis of the elastic resin member.

[0017] The invention according to claim 6 is the invention according to claims 1 to 5.
In any one of the above items, the elastic resin member and the electrode are covered with a protective layer made of a biocompatible material.

The invention according to claim 7 is the invention according to claims 1 to 6
In any one of the above items, the elastic resin member is formed by dispersing carbon particles in silicone rubber.

The invention as defined in claim 8 is defined by claim 1 through claim 7.
In any one of the above items, the electrode is an electrode made of gold or platinum. Next, the "action" of the present invention
Will be described.

According to the first aspect of the invention, since the elastic resin member forming the sensor has elasticity, it elastically deforms when pressure is applied from the outside, and returns to its original shape when the external force disappears. . Further, since the elastic resin member contains a conductive substance, a certain amount of current can flow between the electrodes arranged apart from each other.

When the elastic resin member is elastically deformed by the application of an external force, the distance between the electrodes is increased or decreased depending on the direction of the external force, and the resistance value between the electrodes is also increased or decreased accordingly. That is, it can be understood that this elastic resin member is, so to speak, a resistor connected between the electrodes. Therefore, the degree of deformation of the elastic resin member can be detected based on the change in the resistance value, and further, the direction and magnitude of the external force causing such deformation can be detected. As described above, according to the sensor of the present invention, the pressure applied to the tip of the instrument can be reliably sensed.

Further, in the sensor of the present invention, it is not necessary to form a beam, a slit, a strain gauge, etc., so that the structure is simple as compared with the above-mentioned conventional sensor. Therefore, miniaturization is easy, and manufacturing difficulty is small. Further, as a result of less manufacturing difficulty, the sensor can be made cheaper than the conventional sensor. This also allows the sensor to be disposable.

According to the second aspect of the present invention, in addition to the above actions, the following actions are provided. That is, since the elastic resin member is hollow, the degree of elastic deformation increases when an external force is applied. Therefore, the sensing sensitivity is improved as compared with the case where it is not hollow.

According to the invention described in claim 3, in addition to the above-mentioned action, there is the following action. That is, when the elastic resin member is a tubular body, the tip of the instrument can be fitted into the opening. Therefore, the work of attachment / detachment becomes easy. Further, when the elastic resin member is a tubular body, light passing through along the axial direction is not blocked, so that it can be used as, for example, a sensor for an endoscope.

According to the invention of claim 4, in addition to the above-mentioned action, there is the following action. Central axis direction (ie Z
When an external force from (axial direction) is applied, the elastic resin member expands or contracts according to the magnitude and direction of the external force, and the resistance value between the electrodes accordingly increases or decreases. Therefore, the magnitude and direction of the external force in the Z-axis direction can be detected. Furthermore, when an external force is applied from a direction orthogonal to the central axis direction (that is, the XY axis direction), the head of the elastic resin member tilts in either direction. In this case, an extension portion and a contraction portion are formed on the peripheral surface of the elastic resin member, and if electrodes are present at the same portion, the resistance value between the electrodes increases or decreases accordingly. Therefore, in a fixed case, it is also possible to detect the magnitude and direction of the external force in the X-Y axis direction.

According to the invention of claim 5, in addition to the above-mentioned action, there is the following action. That is, since the two pairs of electrodes are arranged in a mutually orthogonal relationship, both the magnitude and direction of the external force from the X-axis direction and the magnitude and direction of the external force from the Y-axis direction can be reliably detected. .

According to the sixth aspect of the present invention, by covering with the protective layer made of the biocompatible material, direct contact between the elastic resin member and the electrode and the in-vivo substance is avoided. Therefore, even if the elastic resin member or the electrode is not a biocompatible material, the sensor as a whole can be highly compatible with the living body. The term “having biocompatibility” means low reactivity with blood, lymph, and other substances in the body.

According to the invention described in claim 7, the silicone rubber is not only a material having appropriate elasticity but also a material having biocompatibility. Further, the carbon particles dispersed in the silicone rubber may be considered to be a biocompatible material. Therefore, the sensor can be made highly compatible with the living body.

According to the eighth aspect of the present invention, since the electrode made of gold or platinum is a biocompatible material, the sensor can be made highly compatible with a living body.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to FIGS.

This vascular dilatation catheter 1, which is a type of medical instrument inserted into the body, has a thin guide tube to be inserted into the body and an operating means provided at the proximal end of the guide tube for operating the guide tube outside the body. It consists of and. The operation means is composed of, for example, a plurality of wires inserted in a guide tube and a wire operation section for operating them. An air compressor is provided at the base end of the guide tube.

An air supply pipe for balloon expansion is connected to the air compressor. This air supply pipe is inserted into the guide tube, and the tip end side thereof projects from the tip end port of the guide tube. A balloon for vasodilation (not shown) is provided at a position that is returned from the tip 2 of the air supply tube to the base end side by several centimeters. Compressed air is supplied to the balloon via an air supply pipe. Then
When the balloon is inflated, the narrowed blood vessel is expanded.

As shown in FIG. 1, a sensor 3 is attached to the tip 2 of this air supply pipe. This sensor 3
The elastic resin member 4 constituting is a so-called pressure-sensitive rubber in which carbon particles as a conductive substance are non-uniformly dispersed in silicone rubber. The elastic resin member 4 is slightly larger than the air supply pipe and has a cylindrical shape as a whole. A recess is formed on the bottom surface of the elastic resin member 4,
The tip 2 of the air supply tube is fitted in the recess.

On the outer peripheral surface of the elastic resin member 2, two pairs of electrodes 5a, 5b, 6a, 6b made of gold or platinum are arranged apart from each other. In addition, these electrodes 5a, 5
b, 6a, 6b are attached to the outer peripheral surface using, for example, a conductive adhesive.

Of the four electrodes 5a, 5b, 6a and 6b, 5a and 5b are mainly for detecting an external force in the X-axis direction, and 6a and 6b are mainly for detecting an external force in the Y-axis direction. It is a thing. The pair of X-axis direction electrodes 5a and 5b are arranged side by side along the direction of the axis C1 of the elastic resin member 4. Similarly, the pair of Y-axis direction electrodes 6a and 6b are also arranged so as to be aligned along the direction of the axis C1 of the elastic resin member 4. In addition,
X-axis direction electrodes 5a and 5b and Y-axis direction electrodes 6a and 6b
And 90 ° with respect to the axis of the elastic resin member 4
Has made. In addition, as shown in FIG. 1, the distance between the X-axis direction electrodes 5a and 5b and the Y-axis direction electrodes 6a and 6b.
The distance between them is designed to be equal when no external force is applied.

Each of the electrodes 5a, 5b, 6a and 6b has
For example, one end of each wiring 7 is connected by soldering or the like. These wires 7 are insulated from the elastic resin member 4, pass through the inside of the guide tube, and reach the base end portion thereof. Further, the end of the wiring 7 reaching the base end is connected to the input side of a computer having a function of displaying the result of measuring the resistance value on the screen.

Then, the elastic resin member 4, the electrodes 5a, 5
The b, 6a, 6b and the wiring 7 are entirely covered with a silicone rubber cover 8 as a protective layer made of a biocompatible material.

When the elastic resin member 4 comes into contact with the inner wall of the pipe or the like, the elastic resin member 4 receives pressure from the outside. At that time, elastic deformation occurs in the elastic resin member 4. When the external force disappears, the elastic resin member 4 returns to its original shape.

The graph of FIG. 2 (a) shows the relationship between the degree of elastic deformation (Δx) in the X-axis direction and the magnitude of external force (Fx) in the X-axis direction. The “degree of elastic deformation Δx in the X-axis direction” is defined herein as the distance that the tip end surface of the elastic resin member 4 moves in response to elastic deformation when an external force is applied from −X direction to + X direction. In the graph, the horizontal axis is Δx and the vertical axis is Fx. The relationship between the two is expressed by the following equation (1).

Fx = k · Δx (1) [where k is an elastic coefficient determined by the size and material of the elastic resin member 4] Therefore, the above equation (1) is a simple increasing straight line passing through the origin, and Fx and It has a direct proportional relationship with Δx.

Similarly, the graph of FIG. 2B shows the relationship between the degree of elastic deformation in the Y-axis direction (Δy) and the magnitude of the external force in the Y-axis direction (Fy). The “degree of elastic deformation Δy in the Y-axis direction” is −Y here.
Direction is defined as the distance that the tip end surface of the elastic resin member 4 moves due to elastic deformation when an external force is applied in the + Y direction. The graph of FIG. 2C shows the relationship between the degree of elastic deformation in the Z-axis direction (Δz) and the magnitude of the external force in the Z-axis direction (Fz). The “degree of elastic deformation Δz in the Z-axis direction” is defined herein as the distance that the tip end surface of the elastic resin member 4 moves in accordance with the elastic deformation when an external force is applied from −Z direction to + Z direction. Then, the relationship between Fy and Δy and the relationship between Fz and Δz are as follows.

Fy = kΔy (2) Fz = kΔz (3) Therefore, both the equations (2) and (3) are simple increasing straight lines passing through the origin. Further, Fy and Δy, and Fz and Δz are in direct proportion.

Next, a sensing method by the sensor 3 will be described. In performing the sensing, first, between the electrodes 5a-5b for the X-axis direction and the electrode 6 for the Y-axis direction.
Power is supplied between a-6b. Since conductive carbon particles are dispersed in the elastic resin member 4, a certain amount of current flows between the pair of electrodes 5a-5b and between the electrodes 6a-6b. Further, in the initial state of FIG. 1 are not subjected to any external force from any direction, the resistance value Rx is Rx ₀ becomes between X-axis direction electrodes 5a-5b, Y-axis electrode 6a-6
The resistance value Ry between b is Ry ₀ . Incidentally, in the sensor 3 of the present embodiment, the distance between the electrodes 5a-5b and the electrode 6a are
Since the distance between −6b is equal, Rx ₀ = Ry ₀ .

FIG. 3A shows how the elastic resin member 4 is deformed when an external force is applied from the + X direction to the -X direction. In the graph of FIG. 3B, the degree of elastic deformation (Δx) of the elastic resin member 4 at that time and the electrode 5a are shown.
The relationship with the resistance value (Rx) between −5b is shown. In the graph, the symbol Rx is also used as a virtual resistor between the electrodes 5a-5b. Also,
In the same graph, a simple increasing straight line passing through Rx ₀ is drawn. Therefore, when Δx> 0, Rx becomes larger than Rx ₀ , and conversely, when Δx <0, Rx becomes smaller than Rx ₀ .

When an external force is applied from the + X direction to the -X direction, the head of the elastic resin member 4 tilts in the -X direction (see FIG. 3 (a)). In addition, at this time, an extension portion and a contraction portion are formed on the peripheral surface of the elastic resin member 4. In addition,
The degree of contraction is proportional to the moving distance of the tip surface. The part corresponding to the tilted side, that is, the electrode 5a-5
The site where b is installed becomes the contraction site. Therefore, the distance between the electrodes 5a-5b becomes short, and Δx becomes a negative value. Therefore, the value of Rx decreases. On the contrary, the site on the opposite side of this contraction site is the extension site. It should be noted that elastic deformation hardly occurs at the part between the extension part and the contraction part, that is, the part where the electrodes 6a-6b are installed. Therefore, the distance between the electrodes 6a-6b does not change, and Δy = 0. Therefore, the value of Ry does not change.

Then, the computer displays on the display screen, for example, the fact that Ry has not changed and only Rx has increased. In this case, the operator may operate the catheter 1 so that Δx = 0 (that is, Rx = Rx ₀ ). More specifically, by operating the wire operation unit, the traveling direction of the sensor 3 should be directed to the −X direction.

Incidentally, when an external force is applied in the + X direction from the -X direction, the head of the elastic resin member 4 tilts in the + X direction (not shown). As a result, the distance between the electrodes 5a-5b becomes long, and Δx becomes a positive value. Therefore, the value of Rx increases. The distance between the electrodes 5a-5b becomes longer as the moving distance of the tip end surface becomes larger. The electrodes 6a, 6
Since the elastic deformation hardly occurs in the part where b is installed, the value of Ry does not change. From the above, the operator should direct the traveling direction of the sensor 3 to the + X direction.

FIG. 4A shows how the elastic resin member 4 is deformed when an external force is applied from the + Y direction to the -Y direction. In the graph of FIG. 4B, the degree of elastic deformation (Δy) of the elastic resin member 4 at that time and the electrode 6a are shown.
The relationship with the resistance value (Ry) between −6b is shown. In the graph, the symbol Ry is also used as a virtual resistor between the electrodes 6a and 6b. Also,
In the same graph, a simple increasing straight line passing through Ry ₀ is drawn. Therefore, when Δy> 0, Ry becomes larger than Ry ₀ , and conversely, when Δy <0, Ry becomes smaller than Ry ₀ .

When an external force is applied from the + Y direction to the −Y direction, the head of the elastic resin member 4 tilts in the −Y direction (see FIG. 4 (a)). In addition, at this time, an extension portion and a contraction portion are formed on the peripheral surface of the elastic resin member 4. In addition,
The degree of contraction is proportional to the moving distance of the tip surface. The part corresponding to the tilted side, that is, the electrodes 6a, 6
The site where b is installed becomes the contraction site. Therefore, the distance between the electrodes 6a-6b becomes short, and Δy becomes a negative value. Therefore, the value of Ry decreases. On the contrary, the site on the opposite side of this contraction site is the extension site. It should be noted that almost no elastic deformation occurs in the part between the extended part and the contracted part, that is, the part where the electrodes 5a and 5b are installed. Therefore, the distance between the electrodes 5a-5b does not change and Δx = 0. Therefore, the value of Rx does not change.

Then, the computer displays on the display screen, for example, the fact that Rx has not changed and only Ry has increased. In this case, the operator may operate the catheter 1 so that Δy = 0 (that is, Ry = Ry ₀ ). More specifically, it is sufficient to move the sensor 3 in the −Y direction by operating the wire operation unit.

Incidentally, when an external force is applied from the -Y direction to the + Y direction, the head of the elastic resin member 4 tilts in the + Y direction (not shown). As a result, the distance between the electrodes 6a-6b becomes long, and Δy becomes a positive value. Therefore, the value of Ry increases. The value of Rx does not change because almost no elastic deformation occurs in the portion where the electrodes 5a and 5b are installed. From the above, the operator is
Should be advanced in the + Y direction.

FIG. 5A shows how the elastic resin member 4 is deformed when an external force is applied from the -Z direction to the + Z direction. In the graph of FIG. 5B, the degree of elastic deformation (Δz) of the elastic resin member 4 at that time and the electrode 5a are shown.
The relationship with the resistance value (Rx) between −5b is shown. The graph of FIG. 5C shows the relationship between the degree of elastic deformation (Δz) of the elastic resin member 4 and the resistance value (Ry) between the electrodes 6a-6b at that time.

In the graph of FIG. 5B, a simple increasing straight line passing through Rx ₀ is drawn. Therefore, when Δz> 0, Rx becomes larger than Rx ₀ , and conversely, when Δz <0, Rx becomes smaller than Rx ₀ . In the graph of FIG. 5C, a simple increasing straight line passing through Ry ₀ is drawn. Therefore, Ry when the Delta] z> 0 is larger than Ry _0, Ry is smaller than Ry ₀ when the opposite Delta] z <0.

When an external force is applied from the -Z direction to the + Z direction, the elastic resin member 4 will contract entirely along the Z-axis direction. The degree of contraction at this time is proportional to the movement distance of the tip surface. As a result, the electrode 5
The distance between a-5b and the distance between the electrodes 6a-6b are both short (see FIG. 5 (a)). Therefore, Δx and Δy have negative values, and the values of Rx and Ry both decrease.

Then, the computer displays the fact that both Rx and Ry have decreased on, for example, the display screen. In this case, the operator has Δx = 0 and Δy
The catheter 1 may be operated so that = 0. More specifically, it is sufficient to weaken the force for moving the sensor 3.

Incidentally, when an external force is applied from the + Z direction to the −Z direction, the elastic resin member 4 is wholly extended along the Z-axis direction (not shown). As a result, the distance between the electrodes 5a-5b and the distance between the electrodes 6a-6b both become long, and Δx and Δy have positive values. Therefore, Rx,
Both Ry values increase.

The characteristic effects of this embodiment will be listed below. (A) According to the present embodiment, since the elastic resin member 4 is elastically deformed by the external force, the electrode 5a-
The distances between 5b and 6a-6b increase / decrease, and the resistance values Rx, Ry also increase / decrease accordingly. Therefore, this resistance value Rx,
Deformation degree Δ of the elastic resin member 4 based on the change of Ry
It is possible to detect x, Δy, and Δz, and further it is possible to detect the direction and magnitude of the external force causing such deformation. As described above, according to the sensor 3, the pressure applied to the tip of the blood vessel dilation catheter 1 can be reliably sensed. Therefore, the operator can definitely determine the direction in which the tip should be advanced. Therefore, the occurrence rate of operation mistakes such as guiding the tip to a site other than the desired site is extremely low.

(B) With the configuration of this embodiment, it is not necessary to form a beam, a slit, a strain gauge, or the like. Therefore, the structure is simpler than that of the conventional sensor. Therefore, it is easy to miniaturize and the manufacturing difficulty is small. Further, as a result of less manufacturing difficulty, the sensor can be made cheaper than the conventional sensor. This also allows the sensor 3 to be disposable.

(C) In this embodiment, two pairs of electrodes 5a-
5b and 6a-6b are in a relation of being orthogonal to each other, and a pair of members are arranged along the direction of the axis C1. Therefore, it is possible to reliably detect both the magnitude and the direction of the external force in the three directions of the X axis, the Y axis, and the Z axis.

(D) According to the present embodiment, the elastic resin member 4, the electrodes 5a, 5b, 6a, 6b and the wiring 7 are covered with the silicone rubber rubber 8 made of a biocompatible material. Therefore, the elastic resin member 4 and the electrodes 5a, 5b, 6
Direct contact between a, 6b and the like and a substance in the living body (for example, blood) is avoided. Therefore, it is possible to prevent the occurrence of blood clots and the like, and it is possible to obtain the sensor 3 having high compatibility with the living body. If the silicone rubber rubber 8 is applied, the elastic resin member 4 and the electrodes 5a, 5
The room for selecting materials such as b, 6a and 6b is naturally widened. The silicone rubber 8 also has a function as a surface insulating film in the sensor 3.

(E) The silicone rubber used in the elastic resin member 4 of this embodiment is not only a material having appropriate elasticity but also a material having biocompatibility. Also,
Carbon particles dispersed in silicone rubber may also be considered a biocompatible material. Therefore, the sensor 3 as a whole can be made highly biocompatible.
Furthermore, electrodes 5a, 5b, 6a made of gold or platinum,
Since 6b is also a biocompatible material, it contributes to the improvement of biocompatibility of the entire sensor 3.

The present invention is not limited to the above embodiment, and can be modified as follows, for example. (1) Another example 1 in which the present invention is embodied in an endoscope 11 which is a kind of a medical instrument inserted into the body will be described in detail with reference to FIG. Note that detailed description of portions common to the embodiment will be omitted.

The endoscope 11 is composed of a guide tube and operating means, and a white light source or the like is connected to the base end of the guide tube. An optical fiber 12 is connected to the light source. The optical fiber 12 is inserted into the guide tube, and the tip end side thereof is projected from the tip end port of the guide tube. This optical fiber 12
A sensor 13 is attached to the tip of the. The elastic resin member 14 constituting the sensor 13 is a cylindrical body having a through hole 14a unlike the above embodiment.
The tip of the optical fiber 12 is fitted into the opening of the through hole 14 a of the elastic resin member 14. And this other example 1
Then, the X-axis direction electrodes 5a and 5b and the Y-axis direction electrode 6
a and 6b are arranged on the inner peripheral surface of the tubular body. Even with the sensor 13 having such a configuration, basically, the same operational effect as that of the above-described embodiment is exhibited.

Particularly in this sensor 13, the elastic resin member 1
Since 4 is a tubular body, the degree of elastic deformation Δx, Δy, Δz when an external force is applied becomes large. Therefore, the sensing sensitivity is improved as compared with the case where the shape is not hollow. Further, since the tip of the optical fiber 12 can be fitted in the opening, the work of attaching / removing the sensor 13 is facilitated. Further, since the light passing through along the direction of the axis C1 is not blocked, the sensor 13 is extremely suitable for the endoscope 11.

(2) Sensor 21 of another example 2 shown in FIG.
As described above, it is acceptable to provide only a pair of electrodes 5a and 5b on the elastic resin member 4. Of course, it is possible to use three pairs or four pairs.

(3) The electrodes 5a, 5b, 6a, 6b may be formed by a technique such as sputtering or electroless plating, instead of sticking as in the embodiment. Of course, the same applies to the formation of the wiring 7. However, in this case, some insulation structure is required between the wiring 7 and the elastic resin members 4 and 14.

(4) Instead of the silicone rubber 8 as the protective layer, for example, a silicone coat may be selected. Further, the elastic resin members 4, 14 and the electrodes 5a, 5b, 6
It is also permissible to omit the protective layer 8 in certain cases, such as a and 6b being biocompatible materials.

(5) Instead of the carbon resin dispersed in the silicone rubber, metal particles such as gold or copper may be dispersed. (6) In addition to blood vessels, large intestine, small intestine, duodenum, and other gastrointestinal tracts, the sensors 3, 13, 21 of the present invention can be used for urethra, oviduct, bile duct, vagina, lymphatic duct, ear canal, nostril, esophagus,
It is also effective for various medical devices inserted into the bronchus. Further, the sensor 3, 13, 21 of the present invention is attached not only to an externally operated medical device such as the catheter 1 or the endoscope 11 but also to the tip of a self-propelled medical device to which micromachine technology is applied. May be. Of course, the medical device is not limited to humans and may be for animals.

Here, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiment will be listed below together with their effects. (1) The sensor according to claim 6, wherein the protective layer is a silicone rubber cover. With this configuration, it is possible to provide a sensor for a medical instrument that can be inserted into the body and has high compatibility with a living body.

(2) The distal end of the medical instrument for insertion into the body should be advanced by sensing at that position using the sensor according to any one of claims 1 to 8. A method of determining a direction, wherein the direction and magnitude of the pressure applied to the sensor at that time is detected based on the degree of deformation of the elastic resin member, and the pressure is set to a direction such that the pressure becomes zero. A method for determining the advancing direction of an internal-insertion-type medical device, characterized by advancing the tip. By carrying out this method, the tip of the device can be reliably and promptly guided to a desired site in the body.

The technical terms used in this specification are defined as follows. "Guide tube: A long-term flexible tube that is inserted into the body, which is a member that composes a medical device that can be inserted into the body."

[0072]

As described above in detail, according to the invention described in claim 1, not only can the pressure applied to the tip of the instrument be reliably sensed, but also the structure is simple and the size is small and inexpensive. It is possible to provide a sensor for a medical instrument that can be inserted into the body.

According to the invention described in claim 2, in addition to the above effect, the degree of elastic deformation is increased, so that the sensing sensitivity can be improved. According to the invention described in claim 3, in addition to the above effects, the mounting work and the like can be facilitated, and it is suitable as a sensor for an endoscope.

According to the invention described in claim 4, in addition to the above effect, it is possible to detect the magnitude and direction of the external force in a plurality of directions. According to the invention described in claim 5, it is possible to reliably detect the magnitude and direction of the external force in each direction of the X-axis, the Y-axis, and the Z-axis.

According to the invention described in claims 6, 7 and 8,
In addition to the above effects, it is possible to provide a sensor for a medical instrument that can be inserted into the body and has high compatibility with a living body.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an embodiment in which the present invention is embodied in a sensor for a blood vessel dilatation catheter.

2A to 2C are graphs showing the relationship between the degree of elastic deformation of an elastic resin member and the magnitude of external force.

FIG. 3A is a schematic perspective view showing how the elastic resin member is deformed when an external force in the X-axis direction is applied; FIG.
Is a graph showing the relationship between the degree of elastic deformation of the elastic resin member and the resistance value between the electrodes at that time.

FIG. 4A is a schematic perspective view showing how the elastic resin member is deformed when an external force in the Y-axis direction is applied; FIG.
Is a graph showing the relationship between the degree of elastic deformation of the elastic resin member and the resistance value between the electrodes at that time.

FIG. 5A is a schematic perspective view showing how the elastic resin member is deformed when an external force in the Z-axis direction is applied;
(B) and (c) are graphs showing the relationship between the degree of elastic deformation of the elastic resin member and the resistance value between the electrodes at that time.

FIG. 6 is another example 1 in which the present invention is embodied in a sensor for an endoscope.
FIG.

FIG. 7 is a schematic perspective view showing a sensor of Modification 2.

[Explanation of symbols]

1 ... Catheter for blood vessel expansion as a medical instrument inserted into the body, 3, 13, 21 ... Sensor for medical instrument inserted into the body,
4, 14 ... Elastic resin members, 5a, 5b, 6a, 6b ... Electrodes, 7 ... Silicone rubber rubber as a protective layer, 11 ...
An endoscope as a medical instrument inserted into the body, C1 ... Axis, R
x, Ry ... resistance value, Δx, Δy, Δz ... Deformation degree.

Claims (8)

[Claims] 1. A sensor (3, which is attached to the distal end of a medical instrument (1) for insertion into a body and performs sensing at that position.
13, 21), the electrodes (5a, 5b, 6a, 6b) are spaced apart from each other at a plurality of positions in the elastic resin member (4, 14) containing a conductive substance, and the electrodes (5a, 5b, 6a, 6b) insertion type medical device configured to detect the degree of deformation (Δx, Δy, Δz) of the elastic resin member (4, 14) based on the change in resistance value (Rx, Ry). A sensor for instruments. 2. The sensor for an internal medical device according to claim 1, wherein the elastic resin member (14) is hollow. 3. The elastic resin member (14) is a tubular body, and the plurality of electrodes (5a, 5b, 6a, 6b) are arranged on the inner peripheral surface of the tubular body. A sensor for an implantable medical device as described. 4. The plurality of electrodes (5a, 5b, 6a, 6)
4. A pair according to any one of claims 1 to 3, wherein one pair in b) is arranged along the axis (C1) direction of the elastic resin member (4, 14). For medical devices that can be inserted into the body. 5. The plurality of electrodes (5a, 5b, 6a, 6)
b) is two pairs, and one of them is arranged so as to form an angle of 90 ° with the other pair with respect to the axis (C1) of the elastic resin member (4, 14). Three
A sensor for a medical instrument inserted into the body according to any one of 1. 6. The elastic resin member (4, 14) and the electrode (5a, 5b, 6a, 6b) are covered with a protective layer (8) made of a biocompatible material. The sensor for an internal medical device according to any one of claims 1 to 4. 7. The sensor for an internal-body-insertable medical device according to claim 1, wherein the elastic resin members (4, 14) are formed by dispersing carbon particles in silicone rubber. .. 8. The electrodes (5a, 5b, 6a, 6b) are
The sensor for an implantable medical device according to any one of claims 1 to 7, which is an electrode made of gold or platinum.