JP5136747B2 - Bending degree detecting device and bending degree detecting method using the same - Google Patents

Description

The present invention relates to a bend degree detecting device and a bend degree detecting method using the same, and more particularly to a bend degree detecting device for detecting a bend degree of a catheter and a bend degree detecting method using the same. More specifically, the present invention relates to a bending degree detection device that detects the degree of bending of a distal end portion of a catheter in an aneurysm embolization operation, and a bending degree detection method using the same.

  In the cerebral aneurysm embolization operation, the degree of bending of the catheter tip is important information for knowing the degree of filling of an embolization material such as a platinum coil packed into the cerebral aneurysm via the catheter. When placing the catheter tip in the cerebral aneurysm and filling the cerebral aneurysm from the catheter into the cerebral aneurysm, an appropriate curve is applied to the catheter so that the tip of the catheter does not move. Is held on the vessel wall. If the embolic material is sufficiently packed, the embolizing material cannot be packed. Therefore, the force to be packed acts to push the catheter out of the aneurysm or to increase the degree of bending of the catheter. From the state of the catheter tip, it can be determined whether the embolizing material is sufficiently packed.

  Conventionally, the degree of bending of the catheter tip has been detected by attaching a radiopaque marker to the tip of the catheter and observing an X-ray fluoroscopic image of the catheter tip inserted into the blood vessel.

  Further, Patent Documents 1 and 2 disclose optical fiber sensors that are inserted into a blood vessel or a ureter in the body. The optical fiber sensor of Patent Document 1 is provided with three optical fibers subjected to fiber Bragg grating (FBG), and detects the degree of bending of the optical fiber from the wavelength of Bragg reflection. This fiber optic sensor is used to measure the bending of a body tube.

  Moreover, the optical fiber sensor of patent document 2 makes it easy to bend only the specific location rather than other locations by making the clad layer of the specific location of an optical fiber thin, and when pressure is applied to the tip of an optical fiber. In this case, only the specific portion is bent greatly, the transmission loss due to the bending of the optical fiber is increased, and the pressure is measured from the transmission loss.

In Patent Document 3, an optical fiber sensor is formed by providing irregularities on a part of the outer peripheral surface of an optical fiber, and the amount of light leaking from the irregularities on the outer peripheral surface changes according to the degree of bending of the optical fiber sensor. A bending degree detecting device using the above is disclosed. In this bending degree detection device, an optical fiber sensor is attached to an object, and the amount of light emitted from a light source provided at one end of the optical fiber sensor and passed through the optical fiber sensor is provided at the other end of the optical fiber sensor. The light amount detection unit detects the degree of bending of the object based on the detection result.
Special table 2003-515104 gazette JP 7-328128 A US Pat. No. 5,321,257

  However, the method of detecting the degree of bending of the catheter tip by observing a fluoroscopic image has the following problems. That is, since the X-ray fluoroscopic image is a two-dimensional image, it is impossible to clearly observe the movement of the catheter tip that behaves three-dimensionally. In addition, since the embolic material generally does not transmit X-rays, the position of the X-ray opaque marker at the distal end of the catheter becomes unclear when the embolic material is clogged with a cerebral aneurysm.

  Therefore, it is conceivable to use the optical fiber sensors of Patent Documents 1 to 3 for detecting the degree of bending of the catheter tip, but there are some problems. First, the problems of Patent Document 1 are as follows.

  (1) An optical fiber sensor subjected to FBG can detect the degree of bending, but cannot detect the bending direction. In order to detect the bending degree and the bending direction of a specific location, it is necessary to use three or more optical fiber sensors.

  (2) When detecting the bending direction using three optical fiber sensors, in order to obtain the bending direction from the slight difference in the bending degree generated inside and outside the bending of each optical fiber sensor, The sensitivity is low.

  (3) A laser is used as the light source, and an optical system such as a spectroscope for measuring the wavelength of the laser beam is required on the light receiving side. It is necessary to prepare three optical systems, and the measuring instrument becomes very expensive.

  (4) With the current technology, FBG can be applied to glass optical fibers, but cannot be applied to plastic optical fibers that are flexible and difficult to break. Even if a glass optical fiber has a small diameter, it is easily broken. Also, if attached to a flexible guide wire or catheter that is stiff, the flexibility may be lost.

Next, the problems of Patent Document 2 are as follows.
(1) Since the pressure is measured by making the specific portion of the optical fiber easy to bend, when the optical fiber sensor is attached to the guide wire or the catheter, the feature that makes the specific portion easy to bend cannot be utilized.

  (2) This optical fiber sensor can also detect the degree of bending, but cannot detect the bending direction. In order to detect the bending degree and the bending direction of a specific location, it is necessary to use three or more optical fiber sensors.

  Moreover, in the bending degree detection apparatus of patent document 3, since the light source is attached to one end of the optical fiber sensor and the light amount detection unit is attached to the other end, in order to detect the bending degree of the catheter tip using this apparatus. The optical fiber sensor needs to be bent in two and attached to the catheter, and both ends of the optical fiber sensor must be arranged outside the human body. However, if the optical fiber sensor is bent extremely, the light does not propagate, so the degree of bending cannot be detected.

Therefore, the main object of the present invention is that it can be configured with a plastic optical fiber, a bending direction can be detected with a small number of optical fibers, an inexpensive optical system can be used, and a catheter can be used . It is to provide a bending degree detection device capable of detecting the bending degree of a tip portion and a bending degree detection method using the bending degree detection apparatus.

The bending degree detection device according to the present invention inserts a catheter into a human artery, operates a guide wire provided in the catheter, guides the distal end of the catheter into the aneurysm, and curves the distal end of the catheter. After holding the vessel wall, insert a wire into the hollow part of the catheter, use the wire to pack the embolic material into the aneurysm, and pack the embolic material into the aneurysm based on the bending of the tip of the catheter In an embolization operation of an aneurysm to determine whether or not the bending is sufficient, a bending degree detecting device for detecting the bending degree of the distal end portion of the catheter, comprising: an optical fiber sensor including an optical fiber incorporated in the catheter so as to bend together with the catheter; It is provided. The amount a portion of the core and the cladding boundary at the portion corresponding to the distal end of the catheter out of the optical fibers to be uneven form, of the light propagating in the optical fiber, depending on the degree of bend of the distal end of the catheter Light leaks out of the optical fiber from the irregularities . The degree of bend detection device further includes a light source coupled to the proximal end of the optical fiber, and a reflection member provided on-edge of the optical fiber, coupled to the proximal end of the optical fiber, reflecting member is emitted from the light source And a storage element for storing information for converting the output signal of the light amount detector into the degree of bending of the distal end of the catheter .

  Preferably, in a concavo-convex cross section cut along a plane including the central axis of the optical fiber, a tangent to at least a part of the outer periphery of the concavo-convex intersects with the central axis of the optical fiber.

Preferably, the light source is provided between the light source, the light amount detection unit, and the base end of the optical fiber, and the light emitted from the light source is incident on the optical fiber and the light reflected by the reflecting member is incident on the light amount detection unit. An optical branching unit is provided, and the light source, the light amount detection unit, the optical fiber, and the optical branching unit are fixed so as not to be separated with the optical axes aligned.

Preferably, the unevenness has a V-shaped groove in a direction perpendicular to the central axis of the optical fiber on the outer peripheral surface of the optical fiber so that the bottom of the groove reaches the core beyond the interface between the cladding and the core of the optical fiber. multiple cuts at a predetermined pitch Te, Ru der obtained by forming a coating layer with a material which corresponds to the cladding so as to fill a plurality of grooves.

Also, the degree detecting method bending according to the present invention, the bend of the degree detecting device use multiple, catheter tip based on the plurality of information stored in the detection result and a plurality of storage elements of the plurality of light amount detector It is characterized by detecting the degree of bending.

Preferably , a portion of each optical fiber sensor in which the unevenness is formed is incorporated into the distal end portion of the catheter, and the unevenness of each optical fiber sensor is directed in a direction different from the unevenness of the other optical fiber sensors, and a plurality of light amount detection units The bending degree and the bending direction of the distal end portion of the catheter are detected on the basis of the detection result and a plurality of information stored in the plurality of storage elements .

Also preferably, arranged in a plurality of positions at different distances from a plurality of irregularities of the previous end of the catheter of the optical fiber sensor with incorporating unevenness formed portion of each optical fiber sensor to the distal end of the catheter, The degree of bending of the distal end portion of the catheter is detected based on the detection results of the plurality of light quantity detection units and the plurality of information stored in the plurality of storage elements .
Preferably, one of the plurality of bending degree detection devices is used as a correction detection device, and the optical fiber of the correction detection device is not provided with irregularities, and the portion other than the distal end portion of the catheter is used. When the degree of bending is large, the detection result of the light amount detection unit of each other bending degree detection device is corrected based on the detection result of the light amount detection unit of the correction detection device.

Also preferably, on the basis of the detection result of the degree of bend of the distal end of the catheter, and displays the bent state of the distal end of the catheter on the screen of the image display device.

In the bending degree detecting device according to the present invention, irregularities are formed at a part of the boundary between the core and the clad of the optical fiber, and the bending of the tip of the optical fiber out of the light propagating through the optical fiber incorporated in the catheter. an optical fiber sensor the amount of light is to leak from the irregularities to the outside of the optical fiber according to the degree, and a light source coupled to the proximal end of the optical fiber, and a reflection member provided on-edge of the optical fiber, A light amount detector coupled to the proximal end of the optical fiber, for detecting the amount of light emitted from the light source and reflected by the reflecting member, and for converting the output signal of the light amount detector into the degree of bending of the distal end of the catheter And a storage element for storing information . Therefore, since the unevenness is only formed at a part of the boundary between the core and the clad of the optical fiber, the optical fiber can be made of plastic. Further, the bending direction can be detected by two optical fiber sensors having different concave and convex directions, and the bending direction can be detected by a smaller number of optical fibers than in the prior art. Moreover, a spectroscope is unnecessary and an inexpensive optical system can be used. Further, a light source and a light amount detector is provided on the proximal end of the optical fiber sensor, is provided with the reflecting member to its destination end, the optical fiber sensor catheter together inserted into an artery, from the proximal end of the optical fiber sensor of the catheter tip it is possible to detect the degree of bend of.

  1 and 2 are cross-sectional views showing a configuration of an optical fiber sensor 1 of a bending degree detecting device according to an embodiment of the present invention. In particular, FIG. 1 is cut along a plane including a central axis 1a. It is a figure which shows the cross section of the optical fiber sensor 1, FIG. 2 is the II-II sectional view taken on the line of FIG.

  1 and 2, this optical fiber sensor 1 has an uneven surface 5 formed at a part of the boundary between a core 3 and a cladding 4 of an optical fiber 2. The uneven surface 5 includes a plurality of unevenness 5 a arranged in the length direction of the optical fiber 2. The unevenness 5a has, for example, a shape in which a groove having an arcuate bottom is cut in the outer surface of the core 3 in a direction perpendicular to the central axis 1a and the groove is filled with the material of the clad 4. The tangent line L of at least a part of the outer periphery of the unevenness 5a intersects the central axis 1a.

In FIG. 1, the light beam La that does not enter the unevenness 5 a is totally reflected at the boundary surface between the core 3 and the clad 4 and is totally reflected at the boundary surface between the core 3 and the cladding 4, so Go through. On the other hand, the light beam Lb incident on the unevenness 5a is radiated out of the cladding 4 and propagates through the optical fiber 2 because the angle θb formed with the boundary surface between the core 3 and the cladding 4 is larger than the critical angle θc. Can not. In the optical fiber 2, since the refractive index n1 of the core 3 and the refractive index n2 of the clad 4 are very close, the critical angle θc is very small. The critical angle θc is obtained by the equation θc = sin ⁻¹ √ (2 · Δ) ≈√ (2 · Δ). Here, Δ is a relative refractive index difference, and is obtained by the equation Δ = (n1−n2) / n1.

  In FIG. 1, even when the optical fiber 2 is straight, there is a light beam Lb radiated out of the cladding 4. As shown in FIG. 3, when the optical fiber 2 is bent α degrees inward with the uneven surface 5 on the outside, the amount of light emitted outside the cladding 4 increases. Further, if α is negatively bent in the direction opposite to that in FIG. 3, the light rays radiated out of the cladding 4 are reduced. This phenomenon will be described next.

  In the concavo-convex surface 5 of FIG. 1, a curve indicating the boundary surface between the core 3 and the clad 4 is divided into a number of minute straight lines, and the straight line obtained by extending each minute line and the central axis of the optical fiber 2 (ie, the optical fiber). When the angle formed with the central axis 1a) of the sensor 1 is obtained and the relationship between the angle and the number of micro curves is illustrated, the angle distribution curve A in FIG. 4 is obtained. The curve A becomes maximum at 0 degree and becomes a gentle mountain shape.

  When the same processing is performed on a normal optical fiber or a portion without the uneven surface 5 in FIG. 1, the boundary surface of the core 3 and the clad 4 and the central axis of the optical fiber 2 are parallel. An angle distribution curve B is obtained. The curve B becomes maximum at 0 degree and becomes a steep mountain shape.

  In FIG. 4, the angle βc of the light beam emitted outside the cladding 4 is added. βc is obtained by subtracting the bending angle α of the optical fiber 2 from the critical angle θc (βc = θc−α). When the angle β of the light beam with respect to the central axis of the optical fiber 2 is larger than βc, the light beam is emitted outside the cladding 4. Even in a normal optical fiber, α becomes large when it is bent extremely, so that βc approaches 0, and the light beam is radiated out of the cladding, so that the optical fiber cannot propagate light.

  On the uneven surface 5, even if α is 0, there is an uneven surface 5 a having an angle larger than βc, so that light is emitted outside the cladding 4. When the degree of bending of the optical fiber 2 changes, that is, when α changes, βc changes and the amount of light emitted outside the cladding 4 changes.

  The effect of the bending angle α on βc acts positively on one surface and negatively on the opposite surface with respect to the central axis, but in the present invention, the uneven surface 5 is provided only on one surface. The other side is not affected. Therefore, since the light emitted from the cladding 4 increases or decreases due to the change of α, the amount of light passing through the core 3 of the optical fiber 2 is measured to thereby determine the direction perpendicular to the uneven surface 5 (FIG. 2). Then, the degree of bending in the Y-axis direction) can be known.

  Therefore, as shown in FIG. 5, two optical fiber sensors 1 are prepared, the concave / convex surface 5 of one optical fiber sensor 1 is arranged perpendicular to the Y axis, and the concave / convex surface 5 of the other optical fiber sensor 1 is arranged. By arranging them perpendicular to the X axis (that is, parallel to the Y axis), it is possible to detect a two-dimensional bending degree, that is, a bending degree and a bending direction.

  FIG. 6 is a cross-sectional view illustrating a method for forming the uneven surface 5. In FIG. 6, in the method of forming the uneven surface 5, first, a groove having a V-shaped bottom is cut in the outer peripheral surface of the optical fiber 2 in a direction orthogonal to the central axis 1 a. The depth of the groove is set so that the bottom of the groove reaches the core 3 beyond the interface between the core 3 and the clad 4. A plurality of grooves are formed at a predetermined pitch. Next, the coating layer 6 is formed of a material corresponding to the clad 4 so as to fill a plurality of grooves. Thereby, the uneven surface 5 can be easily formed. The optical fiber 2 can be easily processed by using a plastic one, but a glass one may be used.

  7 (a) and 7 (b) are cross-sectional views showing the configuration of the bending degree detecting device using the optical fiber sensor 1 shown in FIGS. 1 to 6. In particular, FIG. ) Is a cross-sectional view taken along the line VIIA-VIIA, and FIG. 7B is a cross-sectional view taken along the line VIIB-VIIB of FIG.

  7A and 7B, the bending degree detection device includes two optical fiber sensors 1. As shown in FIG. 5, the concave and convex surfaces 5 of the two optical fiber sensors 1 are arranged perpendicular to the Y axis and the X axis, respectively. A reflection film 10 for reflecting light is formed on the distal end surface of each optical fiber sensor 1, and the base end surface is connected to the light source unit 12 and the light receiving unit 13 via the Y-branch optical waveguide 11. The two optical fiber sensors 1 are provided in a catheter 14 that is a medical instrument for insertion into a tube such as a blood vessel in the body. The catheter 14 is a flexible hollow tube. The two optical fiber sensors 1 are enclosed in the catheter 14 along the hollow portion 14 a that penetrates the catheter 14, and bend together with the catheter 14.

  A light beam emitted from the light source unit 12 enters the optical fiber sensor 1 via the Y-branch optical waveguide 11, propagates through the optical fiber sensor 1, is reflected by the reflective film 10, and propagates again through the optical fiber sensor 1. Then, the light enters the light receiving unit 13 through the Y-branch optical waveguide 11. At this time, an amount of light according to the degree of bending of the optical fiber sensor 1 out of the light propagating through the optical fiber sensor 1 leaks from the concave / convex surface 5 to the outside. Therefore, the degree of bending and the bending direction of the distal end of the catheter 14 can be detected by reading the amount of light received by the light receiving unit 13 in each of the two optical fiber sensors 1.

  FIG. 8 is a diagram showing the relationship between the reciprocal 1 / R of the radius of curvature R (degree of bending) of the optical fiber sensor 1 and the output (light receiving amount) of a photodiode as the light receiving unit 13. An LED was used as the light source unit 12, and a plastic optical fiber having a diameter of 0.25 mm was used as the optical fiber 2. As shown in FIG. 9, the radius of curvature R of the optical fiber sensor 1 is the distance (mm) from the center of curvature to the portion where the uneven surface 5 of the optical fiber sensor 1 is formed. Further, the polarity of the radius of curvature R of the optical fiber sensor 1 was positive when the optical fiber sensor 1 was bent inward with the concave / convex surface 5 outside, and negative when reversely bent. As shown in FIG. 8, the output of the photosensor increased in proportion to 1 / R. Therefore, the curvature radius R of the optical fiber sensor 1, that is, the curvature radius R of the catheter 14 can be easily obtained from the output of the photosensor.

  The light source unit 12 and the light receiving unit 13 can be manufactured at low cost by using an LED as the light source unit 12 and using a photodiode as the light receiving unit 13. Alternatively, an LED drive circuit may be incorporated in the light source unit 12 and a photodiode amplification circuit may be incorporated in the light receiving unit 13. The Y branch optical waveguide 11 can also be manufactured at low cost by, for example, heat-sealing two plastic optical fibers. The optical fiber sensor 1, the Y-branch optical waveguide 11, the light source unit 12, and the light receiving unit 13 are fixed so as not to be separated in a state where the optical axes are aligned. Therefore, this bending degree detection device can be made disposable together with the catheter 14. If the optical fiber sensor 1 and the light source unit 12 and the light receiving unit 13 are configured separately, their optical axis alignment and reflection at the junction cannot be ignored, and must be calibrated at the time of use, which is inconvenient. .

  In addition, the optical fiber made of plastic has a greater attenuation of light in the optical fiber than the optical fiber made of glass. Since the length of the catheter 14 inserted into the body tube is about 1.5 m, the distance that light propagates through the optical fiber 2 is about 3 m in a reciprocating manner. Therefore, since the optical attenuation in the optical fiber 2 cannot be ignored, it is preferable to use orange light, which is the color with the smallest optical attenuation in the plastic optical fiber. In addition, the photosensitivity of the photodiode or phototransistor used as the light receiving unit 13 is highest with respect to light having a wavelength from red to infrared. On the other hand, since the optical attenuation of infrared rays is large in plastic optical fibers, it is not preferable to use infrared rays. Accordingly, the light emitted from the light source unit 12 is preferably light having a wavelength from orange to red when a plastic optical fiber is used.

  Hereinafter, various modified examples of this embodiment will be described. In the modification of FIG. 10, four pairs of optical fiber sensors 1 are incorporated into the catheter 14. As shown in FIG. 7, each optical fiber sensor 1 is provided with a reflective film 10, a Y-branch waveguide 11, a light source unit 12, and a light receiving unit 13. The four pairs of optical fiber sensors 1 constitute the main parts of the bending degree detection devices S1 to S4, respectively. As shown in FIG. 11, the uneven surface 5 of the optical fiber sensor 1 of the bending degree detection devices S <b> 1 to S <b> 4 is disposed at positions P <b> 1 to P <b> 4 having different distances from the distal end of the catheter 14. In this modified example, the bending degree and the bending direction at the four positions of the distal end portion of the catheter 14 can be detected, so that the bending state of the distal end portion of the catheter 14 can be known in more detail.

  In the modification of FIG. 12, a Y-branch type optical waveguide 15 and a light receiving unit 16 are added to each optical fiber sensor 1 of the bending degree detection device of FIG. The light emitted from the light source unit 12 is incident on the optical fiber sensor 1 through the Y-branch optical waveguides 11 and 15 and is incident on the light receiving unit 16. The light reflected by the reflective film 10 is incident on the light receiving unit 13 via the Y-branch optical waveguides 15 and 11. The amount of light before being incident on the optical fiber sensor 1 is detected by the light receiving unit 16, and the amount of light emitted from the light source unit 12 is kept constant or detected by the light receiving unit 13 based on the detection result. Correct the amount of reflected light. Thereby, measurement with higher accuracy can be performed.

  In the modified example of FIG. 13, a correction memory 17 and a connector 18 are added to each optical fiber sensor 1 of the bending degree detection apparatus of FIG. 7, the reflectance of the reflective film 10, the angular distribution of the uneven surface 5, the branch distribution of the Y-branch type optical waveguide 11, the coupling state between the light source unit 12 and the light receiving unit 13 and the optical fiber sensor 1. As a result, the detection results vary. The correction memory 17 stores information for correcting such variations in detection results. The correction memory 17 is attached to the input terminal group of the connector 18 together with the light source unit 12 and the light receiving unit 13. The output terminal group of the connector 18 is connected to a control unit (not shown) for controlling the bending degree detecting device, calculating the bending degree, calculating the bending direction, and the like. Since the medical catheter 14 is generally disposable, the correction memory 17 and the like are also discarded together with the catheter 14. Therefore, if the catheter 14 is replaced, the correction memory 17 and the like are also replaced together, so that variations in detection results can be easily corrected.

  14A and 14B, the connector 18 of the bending degree detection device shown in FIG. 13 is connected to the display 21 via the arithmetic control device 20. The arithmetic and control unit 20 obtains the degree of bending and the bending direction of the distal end portion of the catheter 14 based on the signal from the bending degree detecting device, and causes the display 21 to display an image of the distal end portion of the catheter 14 in the obtained bent state. When the bending state of the distal end portion of the catheter 14 changes, the image also changes as shown in FIGS. 14 (a) and 14 (b).

  The catheter 14 is inserted into the artery of the human body 22. The operator 23 operates a flexible guide wire (not shown) provided in the catheter 14, and the distal end of the catheter 14 is connected to the cerebral artery via the cerebral artery 24 as shown in FIG. Guide into the aneurysm 25. Next, the operator 23 forms an appropriate curve on the distal end portion of the catheter 14 so that the distal end of the catheter 14 does not move, and holds the catheter 14 on the blood vessel wall by the curved portion. Next, the operator 23 inserts a wire 26 into the hollow portion 14 a of the catheter 14 and uses the wire 26 to pack an embolization material (platinum coil) 27 into the cerebral aneurysm 25. If the embolic material 27 is sufficiently packed, the embolic material 27 cannot be packed, so that the force to be packed acts to increase the degree of bending of the catheter 14 as shown in FIG. The surgeon 23 can determine from the state of the distal end of the catheter 14 displayed on the display 21 whether the embolization material 27 is sufficiently packed.

  In the modified example of FIG. 16, a correction optical fiber sensor 30 is provided in addition to the two optical fiber sensors 1 in order to detect the degree of bending with higher accuracy. The correction optical fiber sensor 30 has the same configuration as the optical fiber sensor 1 except that the uneven surface 5 is not provided. A reflective film 10 is provided on one end face of the correction optical fiber sensor 30, and the other end face is connected to the light source section 12 and the light receiving section 13 via the Y-branch optical waveguide 11.

  When the optical fiber sensor 1 is bent extremely, light leaks at portions other than the uneven surface 5. Therefore, when an extreme bent portion is present in the middle path, the amount of light reaching the light receiving portion 13 is reduced and the catheter is reduced. 14 The accuracy of detecting the degree of bending of the tip is deteriorated. Since the correction optical fiber sensor 30 does not have the uneven surface 5, the decrease in the amount of light in the light receiving unit 13 corresponding to the correction optical fiber sensor 30 is caused by the presence of an extreme bent portion on the way. Therefore, by adding the decrease to the amount of light received by the light receiving unit 13 corresponding to each optical fiber sensor 1, it is possible to eliminate the influence of the extreme bending portion of the intermediate path, and to accurately determine the degree of bending of the distal end portion of the catheter 14. It can be detected well.

  In the modified example of FIG. 17, three optical fiber sensors 1 are used to detect the degree of bending with higher accuracy. The concavo-convex surfaces 5 of the three optical fiber sensors 1 are sequentially shifted by 120 degrees. When the received light amounts of the three light receiving portions 13 connected to the three optical fiber sensors 1 arranged in this way are added, the influence of the uneven surface 5 can be canceled. Therefore, the amount of light received by the three light receiving sections 13 for the three optical fiber sensors 1 is corrected according to the sensitivity, and the average value is calculated. I understand. The degree of bending of the distal end of the catheter 14 can be accurately detected by correcting the amount of light received by each light receiving unit 13 based on the amount of decrease in the average value and calculating the bending direction and the bending degree.

  In this embodiment, the optical fiber sensor 1 is attached to the catheter 14. However, the present invention is not limited to this, and the optical fiber sensor 1 may be attached to an elongated linear body such as a guide wire for guiding the catheter 14. Good.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing which shows the structure of the optical fiber sensor of the bending degree detection apparatus by one Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a figure for demonstrating the principle of the optical fiber sensor shown in FIG. It is another figure for demonstrating the principle of the optical fiber sensor shown in FIG. It is a figure for demonstrating the effect of the optical fiber sensor shown in FIG. It is a figure which illustrates the production method of the optical fiber sensor shown in FIG. It is sectional drawing which shows the structure of the bending degree detection apparatus using the optical fiber sensor shown in FIGS. It is a figure which shows the relationship between the reciprocal number of the curvature radius of the optical fiber sensor shown in FIG. 7, and the output of the photodiode which is a light-receiving part. It is a figure for demonstrating the curvature radius of the optical fiber sensor shown in FIG. It is sectional drawing which shows the example of a change of this embodiment. It is a figure which shows the position of the uneven surface of the four optical fiber sensors shown in FIG. It is sectional drawing which shows the other example of a change of this embodiment. It is sectional drawing which shows the further another example of a change of this embodiment. It is a figure which shows the further another example of a change of this embodiment. It is sectional drawing which shows operation | movement of the catheter shown in FIG. It is sectional drawing which shows the further another example of a change of this embodiment. It is sectional drawing which shows the further another example of a change of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Optical fiber sensor, 1a Central axis, 2 Optical fiber, 3 Core, 4 Cladding, 5 Irregular surface, 5a Irregularity, 6 Coating layer, 10 Reflective film, 11, 15 Y branch type optical waveguide, 12 Light source part, 13, 16 Light receiving part, 14 catheter, 14a hollow part, S1-S4 bending degree detection device, P1-P4 position, 17 correction memory, 18 connector, 20 arithmetic control device, 21 display, 22 human body, 23 operator, 24 cerebral artery, 25 Cerebral aneurysm, 26 wires, 27 embolic material, 30 correction optical fiber sensor.

Claims (9)

After inserting the catheter into the artery of the human body, manipulating the guide wire provided in the catheter to guide the tip of the catheter into the aneurysm, curving the tip of the catheter and holding it on the blood vessel wall, A wire is inserted into the hollow portion of the catheter, the embolization material is packed into the aneurysm using the wire, and the embolization material is packed into the aneurysm based on the bending state of the distal end portion of the catheter. In the embolization operation of the aneurysm to determine whether it is sufficient, a bending degree detection device for detecting the bending degree of the distal end portion of the catheter ,
An optical fiber sensor comprising an optical fiber incorporated into the catheter so as to bend with the catheter;
The uneven portion of the core and the cladding boundary at the portion corresponding to the distal end of the catheter out of the optical fiber is formed, of the light propagating through the pre-Symbol light in the fiber, the bending of the distal portion of the catheter light in an amount corresponding to the degree of being as leaking out of the optical fiber from the uneven,
Furthermore, a light source coupled to the proximal end of said optical fiber,
A reflecting member provided on-edge of the optical fiber,
A light amount detection unit coupled to the base end of the optical fiber and detecting the amount of light emitted from the light source and reflected by the reflecting member ;
A bending degree detection apparatus comprising: a storage element that stores information for converting an output signal of the light amount detection unit into a bending degree of the distal end portion of the catheter .   In the cross section of the unevenness cut along a plane including the central axis of the optical fiber, a tangent to at least a part of the outer periphery of the unevenness intersects with the central axis of the optical fiber, The bending degree detection apparatus according to claim 1. Provided between the light source, the light amount detection unit, and a base end of the optical fiber, the light emitted from the light source enters the optical fiber, and the light reflected by the reflecting member is the light amount detection unit. A light branching unit that is incident on
The bending degree according to claim 1 or 2, wherein the light source, the light amount detection unit, the optical fiber, and the optical branching unit are fixed inseparably in a state where optical axes are aligned. Detection device. The unevenness is
A V-shaped groove in a direction perpendicular to the central axis of the optical fiber is formed on the outer peripheral surface of the optical fiber, and the groove bottom reaches a core beyond the interface between the cladding and the core of the optical fiber. Multiple cuts at the pitch,
4. The bending degree detection apparatus according to claim 1, wherein a coating layer is formed of a material corresponding to the clad so as to fill a plurality of the grooves . A plurality of the bending degree detection devices according to any one of claims 1 to 4 , wherein a plurality of the light amount detection units and a plurality of the information stored in the plurality of storage elements are used. A method for detecting a degree of bending, comprising detecting a degree of bending of a distal end portion of the catheter . Towards the uneven different directions of the irregularities other of the optical fiber sensor the unevenness of each of the optical fiber sensor with incorporating the portion formed at the distal end of the catheter out of the said optical fiber sensor, a plurality and detecting a bending direction and bending degree of the distal portion of the catheter based of the said light amount detector of the detection result and a plurality of said storage elements a plurality of the information stored in, to claim 5 The bending degree detection method described. Each disposed in a plurality of positions at different distances from the previous end of the irregularities the catheter of the plurality of the optical fiber sensor with incorporating the irregularities are formed portion at the distal end of the catheter out of the said optical fiber sensor and, wherein the detecting the degree of bend of the distal portion of the catheter based on the plurality of the information stored in the detection result and a plurality of the storage elements of the plurality of the light quantity detection unit, to claim 5 The bending degree detection method described. One of the plurality of bending degree detection devices is used as a correction detection device, and the optical fiber of the correction detection device is not provided with the unevenness, and the portion other than the distal end portion of the catheter The detection result of the light amount detection unit of each of the other bending degree detection devices is corrected based on the detection result of the light amount detection unit of the correction detection device when the degree of bending is large. The bending degree detection method according to any one of claims 5 to 7. Based on the detection result of the degree of bend of the distal end of the catheter, the bent state of the distal end of the catheter and displaying on the screen of the image display device, in any one of claims 5 to claim 8 The bending degree detection method described.

Images