JP3565982B2 - Catheter with sensor function - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a catheter having a sensor function.
[0002]
[Prior art]
2. Description of the Related Art A catheter for measuring blood pressure and the like by being inserted into various tubes in a human body, for example, a blood vessel or the like is known. Conventionally, this type of catheter has no means for detecting the situation in front of the catheter tube in the traveling direction, and the operator has to rely only on his / her intuition to operate the tube. Therefore, it takes skill to guide the tip of the catheter tube to a desired site.
[0003]
Therefore, it has been conventionally proposed to provide not only a blood pressure sensor but also a sensor mechanism for sensing an obstacle at the tip of the catheter tube and operate the catheter tube based on the sensing result. Hereinafter, an example of the configuration will be described.
[0004]
The distal end portion of the catheter tube is divided into two, a first chamber and a second chamber, by a pressure partition. The semiconductor type pressure sensor chip is accommodated in the first chamber located on the distal end side in a state facing the tube distal direction. Then, the first chamber is filled with a pressure transmitting medium such as silicone gel, and the inlet is sealed with a piston. On the other hand, the one on which the semiconductor type pressure sensor chip is mounted on the pedestal is accommodated in the second chamber located on the base end side, and is filled with the pressure transmitting medium. The sensor chip faces the pressure inlet on the outer periphery of the tube. Note that both sensor chips are provided with bonding pads, respectively, and a signal cable is bonded to them. Further, a back pressure hole is provided in the pedestal so that the air pressure (that is, absolute pressure) in the tube acts on the back surface of the diaphragm of the sensor chip.
[0005]
With the above configuration, the first chamber side functions as an obstacle sensor, and the second chamber side functions as a blood pressure sensor. Each sensor signal is separately output to the outside via each signal cable.
[0006]
[Problems to be solved by the invention]
However, when the sensor chip for obstacle detection is installed separately from the sensor chip for blood pressure measurement as in the conventional catheter, the following problem occurs.
[0007]
A signal cable must be bonded for each sensor chip, a large mounting space is required, and two signal cables are required. Therefore, it is difficult to reduce the diameter of the sensor portion at the distal end of the catheter tube. Also, if the sensor chip is to be assembled separately, the configuration is naturally complicated, and the assembling work is also troublesome. In addition, the necessity of penetrating the back pressure hole in the pedestal is one of the factors that complicates the configuration.
[0008]
Further, in this type of catheter, there is a demand that the presence or absence of an obstacle should be accurately sensed by removing a blood pressure pulsation component.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a catheter having a sensor function that has a relatively simple structure of a sensor portion and can be reduced in size.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, in the invention according to claim 1, a pedestal, a semiconductor type pressure sensor chip, and a pressure transmission medium are accommodated in a catheter tube having a pressure receiving surface at a distal end, and act on the pressure receiving surface. In a catheter configured to transmit pressure to the pressure-sensitive portion of the semiconductor-type pressure sensor chip via the pressure transmission medium, a vertically long sensor chip is mounted on a vertically long pedestal, and the catheter tube A pressure inlet is provided through an outer peripheral portion of the sensor chip, and a first pressure-sensitive portion to which the pressure fluctuation on the pressure receiving surface side is transmitted is disposed in a predetermined area of the sensor chip on a front surface side, and the pressure inlet port side is disposed on a front surface side. A second pressure-sensitive portion to which the pressure fluctuation is transmitted is disposed in another area of the sensor chip, and a pressure partition is provided on the front surface side of the sensor chip for isolating the two pressure-sensitive portions from each other; The catheter with a sensor function, characterized in that partitions the respective pressure reference chamber on the back side of both pressure-sensitive part as its gist.
[0010]
According to a second aspect of the present invention, in the first aspect, the first pressure-sensitive portion is disposed on a distal end side of the tube, and the second pressure-sensitive portion is disposed on a proximal end side of the tube.
According to a third aspect of the present invention, in the first or second aspect, the pressure inlet is sealed with a pressure transmitting medium.
[0011]
Hereinafter, the “action” of the present invention will be described.
First, the operation of the present invention will be described. In the present invention, when there is an obstacle or a stenosis site inside the tube into which the catheter tube is inserted, the insertion resistance of the tube increases, and the pressure acting on the pressure receiving surface also increases accordingly. Such a pressure fluctuation first spreads to the pressure transmitting medium, and finally spreads to the surface side of the first pressure-sensitive portion. That is, the fluctuation of the pressure is transmitted to the surface side of the first pressure-sensitive portion via the pressure transmission medium. The sensor chip converts the pressure fluctuation into an electric signal, and outputs the electric signal to the outside via a wiring such as a signal cable. Therefore, the operator can reliably detect a situation ahead in the traveling direction using the output result as a judgment material. For this reason, it is possible to reliably guide the distal end of the catheter tube to a desired site in the tube. Further, the second pressure-sensitive section in the sensor chip is assigned to another use, for example, for measuring blood pressure. The sensor chip converts the pressure fluctuation into an electric signal, and outputs the electric signal to the outside via the wiring. Therefore, according to this sensor chip, two types of sensing are possible, and further, a part of the external connection terminals and wirings to be provided on the sensor chip can be shared. As a result, the mounting space can be reduced by the omitted structure. Of course, if only one sensor chip is required, the configuration is not complicated, and the assembling work is relatively simple.
[0012]
In the catheter of the present invention, since the pressure reference chambers are provided on the back surfaces of both pressure-sensitive portions, it is not necessary to introduce back pressure into these portions. Therefore, the configuration is simplified by eliminating the need to penetrate the pedestal with a through-hole serving as a back pressure hole.
[0013]
Further, with this catheter, it is possible to remove unnecessary fluctuations in the tube pressure by subtracting the waveform of the tube pressure detection signal from the waveform of the obstacle detection signal. Therefore, this reduces the noise of the obstacle detection signal. In addition, by providing the pressure barrier, the mutual pressure in the region where the obstacle is detected and the region where the tube pressure is detected are not buffered. That is, with this configuration, the sensing accuracy can be reliably increased.
[0014]
According to the second aspect of the present invention, the first pressure-sensitive portion is arranged on the distal end side of the tube, and the second pressure-sensitive portion is arranged on the proximal end side of the tube. Thus, the diameter can be reduced.
[0015]
According to the third aspect of the present invention, since the pressure introducing port is sealed by the pressure transmitting medium, the in vivo substance does not come into direct contact with the sensor chip, which is convenient for in vivo use.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a vascular catheter 1 will be described in detail with reference to FIGS.
[0017]
This vascular catheter 1 is composed of a catheter tube 2 inserted into a blood vessel and operating means provided at a proximal end of the tube 2 for operating the catheter outside the body. The operating means includes, for example, a plurality of wires inserted into the tube 2 and a wire operating unit for operating the wires. At the base end of the tube 2, there is provided an air compressor or the like for sending air to an expansion balloon provided near the distal end of the tube 2. An air supply pipe is connected to the compressor. This air supply pipe is inserted into the tube 2, and a balloon is connected to the distal end thereof. Then, when air is supplied to the balloon, the stenotic blood vessel is expanded from the inner surface side by the action of the inflated balloon.
[0018]
In the catheter 1 of the present embodiment, a sensor assembly having an obstacle sensor unit 3 and a blood pressure sensor unit 4 is formed at the distal end of the catheter tube 2. Hereinafter, the sensor assembly will be described in detail.
[0019]
The sensor assembly includes a pedestal 5, a semiconductor pressure sensor chip 6, a signal cable 7, a piston 8, a pressure transmission medium 9, a pressure partition 10, and the like.
FIG. 2 shows a semiconductor pressure sensor chip 6 as a semiconductor physical quantity sensor chip used in the present embodiment. The sensor chip 6 has a vertically long rectangular shape, and is housed in the catheter tube 2 in a state where the sensor chip 6 is mounted on the pedestal 5 also having a vertically long rectangular shape.
[0020]
A first diaphragm 16 and a second diaphragm 17 as a plurality of pressure sensing portions for sensing pressure fluctuation are formed on a silicon substrate 15 constituting the sensor chip 6 by etching. Four diffusion strain gauges 18 are formed on each of the diaphragms 16 and 17 on the surface (that is, the unetched surface) side of the silicon substrate 15. If the side having the short side is defined as an end of the silicon substrate 15, six bonding pads 19 as external connection terminals are arranged on one end at one end. Each bonding pad 19 and the diffusion strain gauge 18 are connected via a wiring pattern (not shown). FIG. 3B schematically shows the connection.
[0021]
Here, the size of the short side of the silicon substrate 15 and the pedestal 5 is smaller than the inside diameter of the tube 2, and the size of the long side is at least larger than the inside diameter of the tube 2. Therefore, the pedestal 5 with the silicon substrate 15 mounted thereon can be inserted into the elongated tube 2. At this time, the end of the silicon substrate 15 on the side where the bonding pad 19 is formed is disposed on the base end side of the tube 2, and the end on the other side is disposed on the distal end side of the tube 2. That is, the longitudinal direction of the sensor chip 6 and the tube axis direction are in a parallel relationship. Therefore, the sensor chip 6 faces in a direction perpendicular to the tube axis direction, that is, in the tube outer peripheral direction. At this time, the first diaphragm 16 is on the distal end side of the tube, and the second diaphragm 17 is on the proximal end side of the tube.
[0022]
As shown in FIGS. 1 and 2, the pedestal 5 in the present embodiment is made of silicon, and a chip mounting recess 20 to which the sensor chip 6 is to be joined is formed in the center of the upper surface. However, in the present embodiment, no through-hole that functions as a so-called back pressure hole is formed in the sensor chip 6. When the sensor chip 6 is joined to the pedestal 5, a first pressure reference chamber S1 is defined on the back side of the first diaphragm 16 as a first pressure-sensitive portion. In addition, a second pressure reference chamber S2 is defined on the back surface side of the second diaphragm 17 as a second pressure sensing section. These pressure reference chambers S1 and S2 are isolated from the surrounding space.
[0023]
As shown in FIG. 2, a wiring pattern 23 is formed at the base end of the upper surface of the pedestal 5, and a bonding pad 24 is formed at one end thereof. The bonding pads 24 on the pedestal 5 side and the bonding pads 19 on the sensor chip 6 side are electrically connected via bonding wires 25. The other ends of the wiring pattern 23 are soldered with respective leads of the signal cable 7 as wiring. In the present embodiment, there is only one signal cable 7, and the signal cable 7 passes through the tube 2 and reaches the base end thereof.
[0024]
At a position between the first diaphragm 16 and the second diaphragm 17 on the front side of the sensor chip 6, a substantially semicircular pressure barrier 10 is provided. The pressure barrier 10 closes the gap between the pedestal 5 and the sensor chip 6 and the inner wall surface of the tube 2, thereby dividing the inside of the tube 2 into two.
[0025]
As shown in FIG. 1, a pressure introduction port 26 for introducing a pressure in an outer region of the tube into an inner region of the catheter tube 2 is provided through an outer peripheral portion of the catheter tube 2. The pressure inlet 26 is located just above the surface of the second diaphragm 17.
[0026]
A silicone gel 9 as a pressure transmitting medium is filled in a piston sliding space 27 partitioned on the distal end side of the tube 2 by the pressure barrier 10. The silicone gel 9 extends to the surface side of the first diaphragm 16. The opening 2a of the catheter tube 2 is sealed by a piston 8 as a closing member. Therefore, in this embodiment, the outer surface of the piston 8 plays a role as the pressure receiving surface 8a. As a material for forming the piston 8, a biocompatible resin material such as PTFE (polytetrafluoroethylene) or vinyl chloride is used. The silicone gel 9 can also be said to be a biocompatible resin material.
[0027]
Further, the portion through which the pressure introduction port 26 is provided is filled with the silicone gel 9. The silicone gel 9 not only covers the entire surface of the second diaphragm 17 but also extends to the connection between the signal cable 7 and the pedestal 5.
[0028]
Next, sensing by the catheter 1 of the present embodiment having the above-described sensor assembly will be described.
When there is an obstruction (thrombus, tumor, etc.) or a stenosis site inside the blood vessel into which the catheter tube 2 is inserted, the insertion resistance of the tube 2 increases, and the pressure acting on the pressure receiving surface 8a of the piston 8 increases accordingly. To increase. When such a change occurs, the pressure of the silicone gel 9 filled in the piston sliding space 27 increases, and as a result, the pressure applied to the surface of the first diaphragm 16 also increases. That is, a change in pressure occurring outside the distal end of the sensor assembly is indirectly transmitted to the surface of the first diaphragm 16 via the silicone gel 9. Then, the strain of the first diaphragm 16 increases, and the resistance value of the strain gauge 18 on the first diaphragm 16 changes. At this time, the sensor chip 6 converts the change in pressure into an electric signal, and outputs the electric signal to the pedestal 5 via the bonding wire 25. The obstacle detection signal output at this time is based on the pressure in the pressure reference chamber S1. The obstacle detection signal output to the pedestal 5 further reaches the base end of the tube 2 via the signal cable 7.
[0029]
On the other hand, the fluctuation of the blood pressure is transmitted to the front side of the second diaphragm 17 via the silicone gel 9 sealing the pressure inlet 26. Then, the strain of the second diaphragm 17 increases, and the resistance value of the strain gauge 18 on the second diaphragm 17 changes. At this time, the sensor chip 6 converts the change in pressure into an electric signal, and outputs the electric signal to the pedestal 5 via the bonding wire 25. The blood pressure detection signal output at this time is based on the pressure in the pressure reference chamber S2. The blood pressure detection signal output to the pedestal 5 further reaches the base end of the tube 2 outside the body via the signal cable 7.
[0030]
The blood pressure detection signal among the two signals reaching the base end of the tube 2 is visualized without going through any special arithmetic processing. On the other hand, the obstacle detection signal is visualized after the following arithmetic processing. In this case, the above-described arithmetic processing is performed by subtracting the waveform of the blood pressure detection signal (specifically, a waveform having a magnitude of 1 / k, k: a numerical value that varies depending on the size of each part) from the waveform of the obstacle detection signal. To do. This is because by performing such arithmetic processing, unnecessary blood pressure pulsations are removed, and noise of the obstacle detection signal is reduced.
[0031]
Hereinafter, the characteristic effects of the present embodiment will be listed.
(A) In this catheter 1, one of the two diaphragms 16 and 17 in the sensor chip 6 is assigned for detecting an obstacle, and the other is assigned for detecting blood pressure. Therefore, it is possible to perform a plurality of types of sensing using one sensor chip 6. In this case, the bonding pads 19 to be provided on the sensor chip 6 and a part of the signal cable 7 can be shared. More specifically, while a total of eight bonding pads 19 were conventionally required (see FIG. 3A), six bonding pads 19 are sufficient in the present embodiment (see FIG. 3B). . That is, two bonding pads 19 are omitted. Therefore, the sensor chip 6 is reduced in size correspondingly, and the mounting space can be reduced. Further, the fact that only one signal cable 7 is sufficient has a positive effect on space saving. Therefore, it is possible to sufficiently cope with a reduction in the diameter of the sensor assembly at the distal end of the catheter tube 2. Of course, when such a sensor chip 6 is used, complication of the configuration can be avoided, and the assembling operation is relatively simple.
[0032]
(B) In the catheter 1 of the present embodiment, since the pressure reference chambers S1 and S2 are provided on the back surfaces of both the diaphragms 16 and 17, it is not necessary to introduce back pressure to the portions. Therefore, it is not necessary to penetrate the back pressure hole in the pedestal 5, and the configuration is surely simplified by that much.
[0033]
(C) Further, in the catheter 1, as described above, in addition to reducing the noise of the obstacle detection signal, the pressure barrier in the obstacle detection region and the blood pressure detection region is prevented by the pressure barrier 10. Therefore, with this configuration, the sensing accuracy for both the obstacle and the blood pressure is reliably increased.
[0034]
(D) In the catheter 1, both pressure-sensitive portions are the diaphragms 16 and 17 provided with the diffusion strain gauges 18. Therefore, they can be reliably and finely processed by a conventionally known semiconductor process. Therefore, technical difficulty in manufacturing the sensor chip 6 is also small.
[0035]
(E) In this catheter 1, the bonding pads 19 are concentrated on one end of the silicon substrate 15. Therefore, connection with the pedestal 5 side becomes easy and space saving is achieved.
[0036]
(F) According to the catheter 1, the first diaphragm 16 which is the first pressure-sensitive portion is disposed on the distal end side of the tube 2, and the second diaphragm 17 which is the second pressure-sensitive portion is the proximal end of the tube 2. Is located on the side. Therefore, space saving can be achieved as compared with the case where they are arranged upside down, and the diameter of the sensor assembly can be reduced.
[0037]
(G) According to the catheter 1, the pressure inlet 26 is sealed by the silicone gel 9 which is a pressure transmission medium. For this reason, an in-vivo substance such as blood does not come into direct contact with the sensor chip 6, and the induction of a thrombus or the like is prevented. Therefore, it is convenient for use in vivo.
[0038]
(H) FIG. 4 illustrates a catheter 28 in which the configuration of the catheter 1 of the present embodiment is partially changed. The catheter 28 of this modified example is a so-called relative pressure type, not an absolute pressure type as shown in FIG. Therefore, the pressure reference chambers S1 and S2 are not defined on the back surfaces of the two diaphragms 16 and 17, and a back pressure hole is provided in the chip mounting recess 20 of the pedestal 5 instead. The pressure barrier 10 that partitions the space inside the tube 2 is used at two places. Compared to the catheters 1 and 28, the catheter 1 of FIG. 1 is superior to the catheter 28 of FIG. 4 in that the configuration of the pedestal 5 is simple and the pressure barrier 10 is sufficient at one place.
[0039]
Note that the present invention is not limited to only the above-described embodiment, and can be modified as follows, for example.
(1) The number of pressure-sensitive portions in the sensor chip 6 is not limited to two, and may be three or more. For example, in another example of the sensor chip 31 shown in FIG. 5, three diaphragms 16, 17, and 32 are provided in a straight line along the chip longitudinal direction. With this configuration, not only can it be accommodated in the elongated catheter tube 2, but also the third diaphragm 32 can be assigned to sensing physical quantities other than obstacle detection and blood pressure detection. That is, it is possible to sense different physical quantities for each of the diaphragms 16, 17, and 32. However, the third diaphragm 32 may be used as a backup for the first diaphragm 16 or the second diaphragm 17.
[0040]
(2) The pressure-sensitive portions in the sensor chips 6 and 31 are not limited to the diaphragms 16, 17 and 32 having the diffusion strain gauge 18, but may be, for example, a cantilever having the diffusion strain gauge 18. Further, the sensing units in the sensor chips 6 and 31 are not limited to pressure-sensitive units that can sense pressure fluctuations, and may be those that can sense fluctuations in other physical quantities (eg, acceleration, temperature, magnetic force, etc.). Good. Note that the sensing units formed in one sensor chip 6, 31 may be of the same type as in the above embodiment or another example, or may be of a different type.
[0041]
(3) The external connection terminal is not limited to the bonding pad 19, but may be another structure such as a pin.
(4) The pressure barrier 10 may be separate from the sensor chips 6 and 31 and the pedestal 5 as in the embodiment, or may be one in which a part of them is formed in a convex shape (that is, an integrated one). The pressure barrier may be replaced by projecting the inner wall surface side of the catheter tube 2.
[0042]
(5) By omitting the pedestal 5 and inserting the sensor chip 6 directly into the tube 2, it is also possible to partition the pressure reference chambers S1, S2 between the sensor chip 6 and the inner wall surface of the tube 2. . In this case, the size of the catheter tube 2 can be reduced by an amount corresponding to the reduction in the volume of the pedestal 5.
[0043]
(6) The container in which the sensor chips 6 and 31 are to be accommodated is not limited to the catheter tube 2, but may be another elongated container.
Here, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments are listed below together with their effects.
[0044]
(1) In a catheter in which a semiconductor-type pressure sensor chip is housed in a catheter tube, a pressure introduction port is provided in the outer peripheral portion of the catheter tube, and pressure fluctuation due to contact and separation with an obstacle is transmitted to the surface side. A first pressure-sensitive section is arranged in a predetermined area of the sensor chip, and a second pressure-sensitive section to which a pressure change of the pressure inlet side is transmitted to a front surface side is arranged in another area of the sensor chip; A catheter having a sensor function, wherein pressure reference chambers are defined on the back sides of both pressure-sensitive portions. According to this configuration, the structure of the sensor portion can be relatively simplified, and the size can be reduced.
[0045]
(2) In a catheter in which a semiconductor-type physical quantity sensor chip is housed in a catheter tube, a pressure-sensitive portion to which pressure fluctuation due to contact and separation with an obstacle is transmitted is disposed in a predetermined area on the sensor chip, A pressure reference chamber is defined on the back side of the pressure-sensitive portion, and one or a plurality of sensing portions capable of sensing a specific physical quantity are arranged in a region where the first pressure-sensitive portion is not formed. A catheter having a sensor function. According to this configuration, the structure of the sensor portion can be relatively simplified, and the size can be reduced.
[0046]
The technical terms used in this specification are defined as follows.
"Biocompatible: low reactivity with blood, body fluids, lymph, and other biological materials."
[0047]
【The invention's effect】
As described in detail above, according to the first to third aspects of the present invention, it is possible to provide a catheter having a sensor function, in which the structure of the sensor portion is relatively simple and can be reduced in size. .
[0048]
According to the second aspect of the present invention, further downsizing can be achieved. According to the third aspect of the invention, it is possible to make it convenient for use in a living body.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a sensor assembly provided at a distal end of a catheter according to an embodiment.
FIG. 2 is a partially exploded perspective view of the sensor chip, the pedestal, the pressure barrier, and the catheter tube.
3A is a connection diagram of a conventional sensor chip, and FIG. 3B is a connection diagram of a sensor chip of the present embodiment.
FIG. 4 is a sectional view showing a modified example of the catheter.
FIG. 5 is a perspective view of a sensor chip of another example 1.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Catheter, 2 ... Catheter tube, 5 ... Pedestal, 6,31 ... Semiconductor pressure sensor chip, 8a ... Pressure receiving surface, 9 ... Silicone gel as pressure transmission medium, 10 ... Pressure partition, 16 ... First pressure sensitive part A first diaphragm, 17... A second diaphragm as a second pressure-sensitive part, 26... A pressure inlet, 32... A third diaphragm as a third pressure-sensitive part, S1. S2: second pressure reference chamber.

Claims (3)

A pedestal, a semiconductor pressure sensor chip, and a pressure transmitting medium are accommodated in a catheter tube having a pressure receiving surface at a distal end, and a pressure acting on the pressure receiving surface is applied to the semiconductor type pressure sensor chip via the pressure transmitting medium. A catheter configured to be transmitted to the section;
A vertically long sensor chip is mounted on a vertically long pedestal, a pressure inlet is provided in an outer peripheral portion of the catheter tube, and a first pressure-sensitive portion to which pressure fluctuation on the pressure receiving surface side is transmitted to a front surface side. A second pressure-sensitive portion is disposed in a predetermined area of the sensor chip, and a second pressure-sensitive portion to which a pressure fluctuation on the pressure inlet side is transmitted to another surface of the sensor chip. A catheter having a sensor function, wherein a pressure partition is provided for isolating the pressure-sensitive portions from each other, and a pressure reference chamber is defined on the back side of each of the pressure-sensitive portions. The catheter having a sensor function according to claim 1, wherein the first pressure-sensitive portion is disposed on a distal end side of the tube, and the second pressure-sensitive portion is disposed on a proximal end side of the tube. The catheter having a sensor function according to claim 1, wherein the pressure introduction port is sealed by a pressure transmission medium.

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