Curvature Detection System

Abstract

This base member with a curve detection function is provided with: a base member having a longitudinal direction (LD); and a first linear member and a second linear member which extend in the longitudinal direction (LD). The first linear member is fixed to the base member at a first fixation position (P1) and, on one side that is further along the longitudinal direction (LD) than the first fixation position (P1), is movable in the longitudinal direction (LD) relatively to the base member. The second linear member is fixed to the base member at the second fixation position (P2), which is different from the first fixation position (P1) in the longitudinal direction (LD), and, on one side that is further along the longitudinal direction (LD) than the second fixation position (P2), is movable in the longitudinal direction (LD) relatively to the base member. The present invention is capable of detecting a curve in the base member between the first fixation position (P1) and the second fixation position (P2) on the basis of change in relative positions of the first linear member and the second linear member.

Description

[Technical field]

[0001] The present invention relates to a base member with a curvature detection function, a curvature detection system, and an instrument and a balloon catheter equipped with a base member with a curvature detection function. [Background technology]

[0002] Catheter ablation therapy is a treatment method for ablating a target site in the body using a catheter inserted into the body. For example, a target site is destroyed by ablation to treat diseases such as arrhythmia due to atrial fibrillation, endometriosis, and cancer. As a catheter used in catheter ablation therapy, a balloon catheter having a balloon at its distal end is known, as disclosed in JP4062935B2, JP4226040B2, and JP4222152B2.

[0003] The balloon catheter has a catheter shaft to be inserted into the body and a balloon provided at the tip of the catheter shaft. The catheter shaft is made of a long, flexible base member. After the catheter shaft is inserted into the body and guided to the vicinity of the target site, liquid is supplied into the balloon through the internal space of the catheter shaft, and the balloon expands. The liquid in the balloon is temperature-regulated, so that the surface temperature of the balloon can be controlled. By contacting the balloon, which has been regulated to a predetermined surface temperature, with a circumferential target site, for example, a connection site of a pulmonary vein to the atrium, the circumferential target site can be ablated at once.

[0004] However, when the tip of a balloon catheter is curved, inconveniences such as impaired control of the surface temperature of the balloon may occur. For this reason, one of the needs for balloon catheters is the ability to detect the curvature of the tip of the balloon catheter. A similar need exists for other devices (e.g., other types of catheters, medical endoscopes, industrial endoscopes, etc.) that include a long, flexible base member. In the case of a balloon catheter, it is also possible to check the tip of the balloon catheter using an X-ray fluoroscopic image, but the X-ray fluoroscopic image only provides two-dimensional information. For this reason, it is often difficult to determine the presence or absence of curvature of the tip and the direction of curvature from the X-ray fluoroscopic image. JP3917391B2 discloses a medical endoscope that detects the curvature of a long base member using an optical fiber arranged in the base member. However, when detecting the curvature by arranging an optical fiber in the base member, the base member needs to have a certain thickness (external dimensions). For this reason, it is difficult to apply the above-mentioned curvature detection method to devices such as balloon catheters that have strict restrictions on the external dimensions of the base member (catheter shaft). DISCLOSURE OF THEINVENTION

[0005] The present invention has been made in consideration of the above points, and has an object to detect curvature of a base member while suppressing an increase in the external dimensions of the base member.

[0006] The base member with curvature detection function of the present invention includes a base member having a longitudinal direction, and a first linear member and a second linear member extending along the longitudinal direction. The first linear member is fixed to the base member at a first fixing position, and is movable in the longitudinal direction relative to the base member on one side along the longitudinal direction from the first fixing position. The second linear member is fixed to the base member at a second fixing position different from the first fixing position in the longitudinal direction, and is movable in the longitudinal direction relative to the base member on one side along the longitudinal direction from the second fixing position. The curvature of the base member between the first fixing position and the second fixing position can be detected according to a change in the relative position of the first linear member and the second linear member (the end portion on the one side).

[0007] In the curvature detection function-equipped base member of the present invention, the first linear member and the second linear member may be disposed within a lumen provided in the base member.

[0008] In the base member with a curvature detection function of the present invention, the first linear member and the second linear member may be disposed in different lumens.

[0009] In the base member with a curvature detection function of the present invention, the base member may be a tubular member having a wall portion that defines a hollow portion.

[0010] In the base member with curvature detection function of the present invention, the first linear member and the second linear member are disposed within a lumen provided in the base member, and the lumen may be formed in the wall portion.

[0011] In the base member with curvature detection function of the present invention, markers indicating relative positions of the first linear member and the second linear member may be provided on the first linear member and the second linear member.

[0012] The base member with curvature detection function of the present invention may include a third linear member and a fourth linear member extending along the longitudinal direction at a different position circumferentially of the wall portion from the first linear member and the second linear member, the third linear member being fixed to the base member at the first fixed position and movable in the longitudinal direction relative to the base member on one side along the longitudinal direction from the first fixed position, and the fourth linear member being fixed to the base member at the second fixed position and movable in the longitudinal direction relative to the base member on one side along the longitudinal direction from the second fixed position, and the curvature of the base member between the first fixed position and the second fixed position may be detected in response to a change in the relative position of the third linear member and the fourth linear member (the ends on the one side).

[0013] In this case, the third linear member and the fourth linear member may be disposed in another lumen provided at a different position in the circumferential direction of the wall portion from the lumen.

[0014] In this case, markers indicating relative positions of the third linear member and the fourth linear member may be provided on the third linear member and the fourth linear member.

[0015] Alternatively, the curvature detection system of the present invention includes the base member with the curvature detection function, and a sensor that detects a change in the relative position of the first linear member and the second linear member.

[0016] The device of the present invention includes the above-mentioned base member with a curvature detection function.

[0017] The balloon catheter of the present invention includes a catheter shaft having a balloon, an outer cylindrical shaft connected to a proximal end of the balloon, and an inner cylindrical shaft extending into the balloon and connected to a distal end of the balloon, the inner cylindrical shaft passing through the outer cylindrical shaft, and a gap between the inner cylindrical shaft and the outer cylindrical shaft forming a liquid feed path leading to the internal space of the balloon, and a heating member disposed on an outer circumferential surface of the inner cylindrical shaft within the balloon for heating the liquid in the balloon. The inner cylindrical shaft is the base member with the curvature detection function.

[0018] According to the present invention, it is possible to detect curvature of a base member while suppressing an increase in the outer dimensions of the base member. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view illustrating a base member with a curvature detection function and a curvature detection system for explaining a first embodiment. [Diagram 2] FIG. 2 is a side view of the base member with a curvature detection function shown in FIG. [Diagram 3] FIG. 3 corresponds to FIG. 2 and shows a base member with a bending detection function that is bent downward in a region A. [Figure 4] FIG. 3 corresponds to FIG. 2 and shows a base member with a bending detection function that is bent upward in a region A. [Diagram 5] FIG. 3 corresponds to FIG. 2 and shows a base member with a bending detection function that is bent downward in a region B. [Figure 6] FIG. 3 corresponds to FIG. 2 and shows a base member with a bending detection function that is bent upward in a region B. [Figure 7] FIG. 11 is a perspective view illustrating a base member with a curvature detection function and a curvature detection system for explaining a second embodiment. [Figure 8] FIG. 8 is a top view of the base member with a curvature detection function shown in FIG. 7. [Figure 9] FIG. 9 corresponds to FIG. 8 and shows a base member with a curvature detection function curved to the left in region A. [Figure 10] FIG. 9 corresponds to FIG. 8 and shows a base member with a curvature detection function curved to the right in region A. [Figure 11] 9 corresponds to FIG. 8 and shows a base member with a curvature detection function curved leftward in region B. FIG. [Figure 12] 9 corresponds to FIG. 8 and shows a base member with a curvature detection function curved to the right in region B. FIG. [Figure 13] FIG. 13 is a perspective view illustrating a base member with a curvature detection function and a curvature detection system for explaining a third embodiment. [Figure 14] 1A and 1B are diagrams for explaining application examples of a base member with a curvature detection function and a curvature detection system, and show a balloon catheter and a balloon catheter system. [Figure 15] FIG. 15 shows the distal end portion of the balloon catheter of FIG. 14 with the balloon inflated. [Figure 16] FIG. 15 shows the distal end portion of the balloon catheter of FIG. 14 with the balloon in a deflated and expanded state. [Figure 17] 15 is a cross-sectional view showing the distal end portion and the proximal end portion of the catheter body of the balloon catheter shown in FIG. 14. [Figure 18A] 18 is a cross-sectional view taken along line II in FIG. 17. [Figure 18B] FIG. 18 is a cross-sectional view taken along line II-II in FIG. [Figure 18C] FIG. 18 is a cross-sectional view taken along line III-III in FIG. [Figure 19] FIG. 1 shows a conventional balloon catheter pressed against the ostium of a pulmonary vein. [Figure 20] FIG. 1 shows a conventional balloon catheter pressed against the ostium of a pulmonary vein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] <First embodiment> Hereinafter, the first embodiment of the present invention will be described with reference to the specific examples shown in the drawings. In the drawings attached to this specification, the scale and the aspect ratio are appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding. In addition, the terms such as "parallel," "orthogonal," and "same" that specify the shape, geometric conditions, and their degree, as well as the values ​​of lengths and angles, used in this specification, are not limited to their strict meanings, but are interpreted to include a range within which similar functions can be expected.

[0021] 1 includes a base member 2 with a curvature detection function, a distance displacement sensor 8, and a display device 9. The base member 2 with a curvature detection function also includes a base member 3 having a longitudinal direction LD, and a first linear member 6 and a second linear member 7 extending along the longitudinal direction LD.

[0022] The base member 3 is bendable. As the material of the base member 3, various materials such as metal, ceramic, and resin can be used depending on the application of the base member 2 with a bending detection function.

[0023] In the illustrated example, the base member 3 is a cylindrical member having a wall portion 4 that defines a hollow portion 3a. Of course, the shape of the base member 3 is not limited to a cylindrical shape, and other shapes such as a plate shape or a column shape can also be used.

[0024] The base member 3 is provided with a first lumen 4a and a second lumen 4b extending adjacent to each other in the longitudinal direction LD. The first lumen 4a and the second lumen 4b are formed in the wall portion 4 of the base member 3.

[0025] A first linear member 6 is disposed in the first lumen 4a, and a second linear member 7 is disposed in the second lumen 4b. By disposing the linear members 6, 7 in the lumens 4a, 4b, the risk of damage to the linear members 6, 7 is reduced. In addition, by disposing the linear members 6, 7 in different lumens 4a, 4b, the risk of the linear members 6, 7 becoming entangled is reduced.

[0026] The first linear member 6 has a first end 6a and a second end 6b located on one side of the first end 6a along the longitudinal direction LD. The first end 6a of the first linear member 6 is fixed to a first fixing position P1 of the base member 3 within the first lumen 4a. The other portion of the first linear member 6 including the second end 6b is disposed within the first lumen 4a so as to be movable relative to the base member 3 in the longitudinal direction LD.

[0027] The second linear member 7 also has a first end 7a and a second end 7b located on one side of the first end 7a along the longitudinal direction LD. The first end 7a of the second linear member 7 is fixed to a second fixing position P2 of the base member 3 in the second lumen 4b. The other part of the second linear member 7 including the second end 7b is arranged in the second lumen 4b so as to be movable in the longitudinal direction LD relative to the base member 3 and the first linear member 6. The second fixing position P2 is located at a position different from the first fixing position P1 in the longitudinal direction LD, and in the illustrated example, is located on one side of the first fixing position P1 along the longitudinal direction LD.

[0028] The first linear member 6 and the second linear member 7 are made of a material that is less elastic than the base member 3 and can bend along the curvature of the base member 3. As the material for the first linear member 6 and the second linear member 7, various materials such as metal and resin can be used depending on the application of the base member 2 with a curvature detection function. The first linear member 6 and the second linear member 7 are preferably made of the same material.

[0029] In the illustrated example, the lengths of the first linear member 6 and the second linear member 7 are determined such that the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 are at the same position in the longitudinal direction LD when the base member 3 is not curved at any position in the longitudinal direction LD as shown in Figures 1 and 2. However, this is not limited to this as long as a change in the relative position between the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 can be detected as described later.

[0030] In the base member 2 with curvature detection function configured in this manner, the curvature of the base member 3 between the first fixing position P1 and the second fixing position P2 can be detected in response to a change in the relative position of the second ends 6b, 7b of the first linear member 6 and the second linear member 7. In particular, the curvature of the base member 3 in the up-down direction VD can be detected.

[0031] In the following description, the side of the base member 3 on which the first linear member 6 and the second linear member 7 are provided is referred to as the "upper side", and the side opposite the upper side is referred to as the "lower side". The direction from the lower side to the upper side is referred to as the "upper direction", and the direction from the upper side to the lower side is referred to as the "lower direction". In addition, in Figs. 2 to 6, for ease of understanding, the first linear member 6 and the second linear member 7 are shown at different positions in the vertical direction, but it should be noted that the first linear member 6 and the second linear member 7 are arranged at positions overlapping each other when viewed from the side of the base member 2 with a curvature detection function.

[0032] 2 to 6, the relative movement of the second end portions 6b, 7b of the first linear member 6 and the second linear member 7 caused by the bending of the base member 3 will be described.

[0033] As shown in FIG. 2, when the base member 3 is not curved at any position in the longitudinal direction LD, as described above, the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 are at the same position in the longitudinal direction LD.

[0034] As shown in FIG. 3, when the base member 3 is curved downward in the region A between the first fixing position P1 and the second fixing position P2, the region above the region A (the region where the first linear member 6 is arranged) is stretched by the curve. As a result, for the first linear member 6 extending in the region A, the second end 6b moves to the other side along the longitudinal direction LD (left side in FIG. 3) relative to the base member 3. On the other hand, for the second linear member 7 not extending in the region A, the second end 7b does not move relative to the base member 3. As a result, the second end 6b of the first linear member 6 moves to the other side along the longitudinal direction LD (left side in FIG. 3) relative to the second end 7b of the second linear member 7, and the relative positions of the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 change.

[0035] 4, when the base member 3 is curved upward in the region A, the region above the region A (the region where the first linear member 6 is arranged) contracts due to the curvature. As a result, for the first linear member 6 extending in the region A, the second end 6b moves to one side along the longitudinal direction LD relative to the base member 3 (the right side in FIG. 4). On the other hand, for the second linear member 7 not extending in the region A, the second end 7b does not move relative to the base member 3. As a result, the second end 6b of the first linear member 6 moves relative to the second end 7b of the second linear member 7 to one side along the longitudinal direction LD (the right side in FIG. 4), causing a change in the relative positions of the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7.

[0036] On the other hand, as shown in FIG. 5, when the base member 3 is curved downward in the region B located on one side (the right side in FIG. 5) along the longitudinal direction LD from the second fixing position P2, the region above the region B (the region where the first linear member 6 and the second linear member 7 are arranged) is stretched by the curve. As a result, the second end 6b of the first linear member 6 extending in the region B moves to the other side (the left side in FIG. 5) along the longitudinal direction LD with respect to the base member 3. Also, the second end 7b of the second linear member 7 extending in the region B moves to the other side (the left side in FIG. 5) along the longitudinal direction LD with respect to the base member 3. The distance that the second end 7b of the second linear member 7 moves relative to the base member 3 is the same as the distance that the second end 6b of the first linear member 6 moves relative to the base member 3. As a result, the relative positions of the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 do not change.

[0037] Also, as shown in FIG. 6, when the base member 3 is curved upward in the region B, the region above the region B (the region where the first linear member 6 and the second linear member 7 are arranged) contracts due to the curvature. As a result, the second end 6b of the first linear member 6 extending in the region B moves to one side (the right side in FIG. 6) along the longitudinal direction LD with respect to the base member 3. Also, the second end 7b of the second linear member 7 extending in the region B moves to one side (the right side in FIG. 6) along the longitudinal direction LD with respect to the base member 3. The distance that the second end 7b of the second linear member 7 moves relative to the base member 3 is the same as the distance that the second end 6b of the first linear member 6 moves relative to the base member 3. As a result, the relative positions of the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 do not change.

[0038] Therefore, by detecting the presence or absence of a change in the relative position between the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7, it is possible to detect the presence or absence of curvature of the base member 3 in the region A. In addition, by detecting the direction of displacement of the second end 6b of the first linear member 6 relative to the second end 7b of the second linear member 7, it is possible to detect the curvature direction (upward or downward) of the base member in the region A.

[0039] Furthermore, the amount of displacement of the second end 6b of the first linear member 6 relative to the second end 7b of the second linear member 7 when the base member 3 is curved in region A varies depending on the degree of the curvature (the angle of the direction in which the central axis X of the base member 3 at fixed position P2 extends relative to the direction in which the central axis X of the base member 3 at fixed position P1 extends). Therefore, by detecting the amount of displacement, the degree of curvature of the base member 3 in region A can be detected.

[0040] Next, the distance displacement sensor 8 will be described. The distance displacement sensor 8 detects a change in the relative position between the second ends 6b, 7b of the first linear member 6 and the second linear member 7. The distance displacement sensor 8 includes a first sensor 8a and a second sensor 8b, and can detect a change in the relative position between the first sensor 8a and the second sensor 8b. The first sensor 8a is fixed to the second end 6b of the first linear member 6. The second sensor 8b is fixed to the second end 7b of the second linear member 7. The distance displacement sensor 8 is electrically connected to the display device 9, and when a change occurs in the relative position of the first sensor 8a with respect to the second sensor 8b, the distance displacement sensor 8 inputs a signal according to the displacement direction and displacement amount of the first sensor 8a with respect to the second sensor 8b to the display device 9.

[0041] The display device 9 determines the direction and degree of curvature of the base member 3 in the region A based on the signal input from the distance displacement sensor 8, and displays it on the display section 9a.

[0042] In the illustrated example, the display device 9 indicates the direction of curvature detected by the distance displacement sensor 8 as "up", "middle" and "down". Specifically, when the base member 3 is not curved in region A as shown in Figs. 2, 5 and 6, the display device 9 indicates the direction of the curvature as "middle". When the base member 3 is curved downward in region A as shown in Fig. 3, the display device 9 indicates the direction of the curvature as "down". When the base member 3 is curved upward in region A as shown in Fig. 4, the display device 9 indicates the direction of the curvature as "up".

[0043] In the illustrated example, the display device 9 indicates the degree of the curvature grasped by the distance displacement sensor 8 with "large" and "small". Specifically, when the displacement amount of the first sensor 8a relative to the second sensor 8b (hence, the displacement amount of the second end 6b of the first linear member 6 relative to the second end 7b of the second linear member 7) is 0 (in the case of Figs. 2, 5 and 6), the display device 9 does not display the degree of the curvature. When the displacement amount of the first sensor 8a relative to the second sensor 8b is greater than 0 and less than a predetermined value, the display device 9 indicates the degree of the curvature with "small". When the displacement amount of the first sensor 8a relative to the second sensor 8b is equal to or greater than the predetermined value, the display device 9 indicates the degree of the curvature with "large".

[0044] <Second embodiment> Next, a curvature detection system 11 according to a second embodiment will be described with reference to FIGS.

[0045] 7 to 12 differs from the curvature detection system 1 shown in FIGS. 1 to 6 in that the base member 12 with curvature detection function further includes a third linear member 16 and a fourth linear member 17 extending in the longitudinal direction LD, and a second distance displacement sensor 18. The other configurations are substantially the same as those of the curvature detection system 1 shown in FIGS. 1 to 6. In the example shown in FIGS. 7 to 12, the same parts as those of the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0046] 7 to 12, the base member 3 further has a third lumen 4c and a fourth lumen 4d that are adjacent to each other and extend in the longitudinal direction LD. The third lumen 4c and the fourth lumen 4d are formed in the wall portion 4 of the base member 3.

[0047] 7, the third lumen 4c and the fourth lumen 4d are provided at different positions in the circumferential direction RD of the cylindrical wall portion 4 of the base member 3 from the first lumen 4a and the second lumen 4b. In the illustrated example, the third lumen 4c and the fourth lumen 4d are provided at positions rotated 90° clockwise around the central axis X of the base member 2 from the first lumen 4a and the second lumen 4b when viewing the base member 3 from one end (the end on the region B side) in the longitudinal direction LD.

[0048] A third linear member 16 is disposed in the third lumen 4c, and a fourth linear member 17 is disposed in the fourth lumen 4d. By disposing the linear members 16, 17 in the lumens 4c, 4d, the risk of damage to the linear members 16, 17 is reduced. In addition, by disposing the linear members 16, 17 in different lumens 4c, 4d, the risk of the linear members 16, 17 becoming entangled is reduced.

[0049] The third linear member 16 has a first end 16a and a second end 16b located on one side of the first end 16a along the longitudinal direction LD. The first end 16a of the third linear member 16 is fixed to a first fixing position P1 of the base member 3 within the third lumen 4c. The other portion of the third linear member 16 including the second end 16b is disposed within the third lumen 4c so as to be movable relative to the base member 3 in the longitudinal direction LD.

[0050] The fourth linear member 17 also has a first end 17a and a second end 17b located on one side of the first end 17a along the longitudinal direction LD. The first end 17a of the fourth linear member 17 is fixed to a second fixing position P2 of the base member 3 within the fourth lumen 4d. The other portion of the fourth linear member 17 including the second end 17b is disposed within the fourth lumen 4d so as to be movable relative to the base member 3 and the third linear member 16 in the longitudinal direction LD.

[0051] The third linear member 16 and the fourth linear member 17 are made of a material that is less elastic than the base member 3 and can bend along the curvature of the base member 3. As with the first linear member 6 and the second linear member 7, various materials such as metal and resin can be used as the material for the third linear member 16 and the fourth linear member 17 depending on the application of the base member 12 with a curvature detection function. The third linear member 16 and the fourth linear member 17 are preferably made of the same material.

[0052] In the illustrated example, the lengths of the third linear member 16 and the fourth linear member 17 are determined such that the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 are at the same position in the longitudinal direction LD when the base member 3 is not curved at any portion along the longitudinal direction LD as shown in Figures 7 and 8. However, this is not limited to this as long as a change in the relative position between the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 can be detected as described later.

[0053] In the base member 12 with curvature detection function configured in this manner, the curvature of the base member 3 between the first fixing position P1 and the second fixing position P2 can be detected in response to a change in the relative positions of the second ends 16b, 17b of the third linear member 16 and the fourth linear member 17. In particular, the curvature of the base member 3 in the left-right direction HD can be detected.

[0054] In the following description, the side of the base member 3 on which the third linear member 16 and the fourth linear member 17 are provided is referred to as the "right side", and the side opposite to the right side is referred to as the "left side". The direction from the left side to the right side is referred to as the "right direction", and the direction from the right side to the left side is referred to as the "left direction". In addition, in Figs. 8 to 12, for ease of understanding, the third linear member 16 and the fourth linear member 17 are shown at different positions in the left-right direction, but it should be noted that the third linear member 16 and the fourth linear member 17 are arranged at positions overlapping each other when the base member 12 with curvature detection function is viewed from above.

[0055] 8 to 12, the relative movement of the second ends 16b, 17b of the third linear member 16 and the fourth linear member 17 caused by the bending of the base member 3 will be described.

[0056] As shown in Figure 8, when the base member 3 is not curved at any portion along the longitudinal direction LD, as described above, the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 are at the same position in the longitudinal direction LD.

[0057] As shown in FIG. 9, when the base member 3 is curved leftward in the region A, the region on the right side of the region A (the region where the third linear member 16 is arranged) is stretched by the curve. As a result, for the third linear member 16 extending in the region A, the second end 16b moves to the other side along the longitudinal direction LD relative to the base member 3 (the left side in FIG. 9). On the other hand, for the fourth linear member 17 not extending in the region A, the second end 17b does not move relative to the base member 3. As a result, the second end 16b of the third linear member 16 moves relative to the second end 17b of the fourth linear member 17 to the other side along the longitudinal direction LD (the left side in FIG. 9), and the relative positions of the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 change.

[0058] 10, when the base member 3 is curved to the right in the region A, the region on the right side of the region A (the region where the third linear member 16 is arranged) contracts due to the curvature. As a result, for the third linear member 16 extending in the region A, the second end 16b moves relatively to one side along the longitudinal direction LD with respect to the base member 3 (the right side in FIG. 10). On the other hand, for the fourth linear member 17 not extending in the region A, the second end 17b does not move relative to the base member 3. As a result, the second end 16b of the third linear member 16 moves relatively to one side along the longitudinal direction LD with respect to the second end 17b of the fourth linear member 17 (the right side in FIG. 10), and the relative positions of the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 change.

[0059] On the other hand, as shown in FIG. 11, when the base member 3 is curved to the left in the region B, the region on the right side of the region B (the region where the third linear member 16 and the fourth linear member 17 are arranged) is stretched by the curve. As a result, the second end 16b of the third linear member 16 extending in the region B moves to the other side (left side in FIG. 11) along the longitudinal direction LD with respect to the base member 3. Also, the second end 17b of the fourth linear member 17 extending in the region B moves to the other side (left side in FIG. 11) along the longitudinal direction LD with respect to the base member 3. The distance by which the second end 17b of the fourth linear member 17 moves relative to the base member 3 is the same as the distance by which the second end 16b of the third linear member 16 moves relative to the base member 3. As a result, the relative positions of the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 do not change.

[0060] Also, as shown in FIG. 12, when the base member 3 is curved to the right in the region B, the region on the right side of the region B (the region where the third linear member 16 and the fourth linear member 17 are arranged) contracts due to the curvature. As a result, the second end 16b of the third linear member 16 extending in the region B moves to one side (the right side in FIG. 12) along the longitudinal direction LD with respect to the base member 3. Also, the second end 17b of the fourth linear member 17 extending in the region B moves to one side (the right side in FIG. 12) along the longitudinal direction LD with respect to the base member 3. The distance by which the second end 17b of the fourth linear member 17 moves relative to the base member 3 is the same as the distance by which the second end 16b of the third linear member 16 moves relative to the base member 3. As a result, the relative positions of the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17 do not change.

[0061] Therefore, by detecting the presence or absence of a change in the relative position of the second end 16b of the third linear member 16 and the second end 17b of the fourth linear member 17, it is possible to detect the presence or absence of curvature of the base member 3 in the region A. In addition, by detecting the direction of displacement of the second end 16b of the third linear member 16 relative to the second end 17b of the fourth linear member 17, it is possible to detect the curvature direction (rightward or leftward) of the base member in the region A.

[0062] Furthermore, the amount of displacement of the second end 16b of the third linear member 16 relative to the second end 17b of the fourth linear member 17 when the base member 3 is curved in region A varies depending on the degree of the curvature (the angle of the direction in which the central axis X of the base member 3 at fixed position P2 extends relative to the direction in which the central axis X of the base member 3 at fixed position P1 extends). Therefore, by detecting the amount of displacement, the degree of curvature of the base member 3 in region A can be detected.

[0063] Furthermore, by combining the curvature detection results obtained using the third linear member 16 and the fourth linear member 17 with the curvature detection results obtained using the first linear member 6 and the second linear member 7, the curvature direction of the base member 3 in region A can be grasped in three dimensions.

[0064] Next, the second distance displacement sensor 18 will be described. The second distance displacement sensor 18 detects a change in the relative position of the second ends 16b, 17b of the third linear member 16 and the fourth linear member 17. The second distance displacement sensor 18 includes a third sensor 18a and a fourth sensor 18b, and can detect a change in the relative position of the third sensor 18a and the fourth sensor 18b. The third sensor 18a is fixed to the second end 16b of the third linear member 16. The fourth sensor 18b is fixed to the second end 17b of the fourth linear member 17. The second distance displacement sensor 18 is electrically connected to the display device 9, and when a change occurs in the relative position of the third sensor 18a with respect to the fourth sensor 18b, the second distance displacement sensor 18 inputs a signal according to the displacement direction and displacement amount of the third sensor 18a with respect to the fourth sensor 18b to the display device 9.

[0065] The display device 9 determines the direction and degree of curvature of the base member 3 in the region A based on the signal input from the second distance displacement sensor 18, and displays it on the display section 9b.

[0066] In the illustrated example, the display device 9 indicates the direction of curvature detected by the second distance displacement sensor 18 as "right", "middle" and "left". Specifically, when the base member 3 is not curved in region A as shown in Figs. 8, 11 and 12, the display device 9 indicates the direction of the curvature as "middle". When the base member 3 is curved to the left in region A as shown in Fig. 9, the display device 9 indicates the direction of the curvature as "left". When the base member 3 is curved to the right in region A as shown in Fig. 10, the display device 9 indicates the direction of the curvature as "right".

[0067] In the illustrated example, the display device 9 indicates the degree of curvature grasped by the second distance displacement sensor 18 as "large" or "small". Specifically, when the displacement amount of the third sensor 18a relative to the fourth sensor 18b (hence, the displacement amount of the second end 16b of the third linear member 16 relative to the second end 17b of the fourth linear member 17) is 0 (as in the cases of Figs. 8, 11 and 12), the display device 9 does not display the degree of the curvature. When the displacement amount of the third sensor 18a relative to the fourth sensor 18b is greater than 0 and less than a predetermined value, the display device 9 indicates the degree of the curvature as "small". When the displacement amount of the third sensor 18a relative to the fourth sensor 18b is equal to or greater than the predetermined value, the display device 9 indicates the degree of the curvature as "large".

[0068] <Third embodiment> Next, a bend detection system 101 according to a third embodiment will be described with reference to FIG.

[0069] The example shown in Fig. 13 differs from the curvature detection system 1 shown in Figs. 1 to 6 in that the base member 102 with curvature detection function further includes a fifth linear member 108 extending in the longitudinal direction LD adjacent to the first linear member 6 and the second linear member 7. Also, the distance displacement sensor 8 further includes a fifth sensor 8c. The other configurations are substantially the same as those of the curvature detection system 1 shown in Figs. 1 to 6. In the example shown in Fig. 13, the same parts as those of the first embodiment shown in Figs. 1 to 6 are denoted by the same reference numerals and detailed description thereof will be omitted.

[0070] 13, the base member 3 further has a fifth lumen 4e extending in the longitudinal direction LD adjacent to the first lumen 4a and the second lumen 4b. The fifth lumen 4e is formed in the wall portion 4 of the base member 3.

[0071] A fifth linear member 108 is disposed in the fifth lumen 4e. By disposing the fifth linear member 108 in the lumen 4e, the risk of damage to the fifth linear member 108 is reduced. In addition, by disposing the linear members 6, 7, 108 in different lumens 4a, 4b, 4e, the risk of the linear members 6, 7, 108 becoming entangled is reduced.

[0072] The fifth linear member 108 has a first end 108a and a second end 108b located on one side of the first end 108a along the longitudinal direction LD. The first end 108a of the fifth linear member 108 is fixed to the third fixing position P3 of the base member 3 in the fifth lumen 4e. The other part of the fifth linear member 108 including the second end 108b is arranged in the fifth lumen 4e so as to be movable in the longitudinal direction LD relative to the base member 3 and relative to the first linear member 6 and the second linear member 7. The third fixing position P3 is located at a position different from the first fixing position P1 and the second fixing position P2 in the longitudinal direction LD, and in the illustrated example, is located on one side of the second fixing position P2 along the longitudinal direction LD.

[0073] The fifth linear member 108 is made of a material that is less elastic than the base member 3 and can bend along the curvature of the base member 3. As with the first linear portion 6 and the second linear member 7, various materials such as metal and resin can be used as the material of the fifth linear member 108 depending on the application of the base member 102 with a curvature detection function. The fifth linear member 108 is preferably made of the same material as the first linear member 6 and the second linear member 7.

[0074] In the illustrated example, the length of the fifth linear member 108 is determined so that the second end 108b of the fifth linear member 108 is at the same position in the longitudinal direction LD as the second end 6b of the first linear member 6 and the second end 7b of the second linear member 7 when the base member 3 is not curved at any portion along the longitudinal direction LD as shown in Fig. 13. However, this is not limited to this as long as a change in the relative position between the second end 6b of the second linear member 6 and the second end 108b of the fifth linear member 108 can be detected as described later.

[0075] In the base member 102 with curvature detection function configured in this manner, the curvature of the base member 3 between the first fixing position P1 and the second fixing position P2 can be detected in response to a change in the relative position of the second ends 6b, 7b of the first linear member 6 and the second linear member 7. Furthermore, the curvature of the base member 3 in the region B1 between the second fixing position P2 and the third fixing position P3 can be detected in response to a change in the relative position of the second ends 7b, 108b of the second linear member 7 and the fifth linear member 108.

[0076] Next, the distance displacement sensor 8 of the third embodiment will be described. As described above, the distance displacement sensor 8 of this embodiment has the fifth sensor 8c in addition to the first sensor 8a and the second sensor 8b. The fifth sensor 8c is fixed to the second end 108b of the fifth linear member 108. The distance displacement sensor 8 of this embodiment can detect the change in the relative position of the second sensor 8b and the fifth sensor 8c in addition to the change in the relative position of the first sensor 8a and the second sensor 8b. When the relative position of the first sensor 8a to the second sensor 8b changes, the distance displacement sensor 8 of this embodiment inputs a signal corresponding to the displacement direction and displacement amount of the first sensor 8a to the second sensor 8b to the display device 9. Furthermore, when the relative position of the second sensor 8b to the fifth sensor 8c changes, the distance displacement sensor 8 of this embodiment inputs a signal corresponding to the displacement direction and displacement amount of the second sensor 8b to the fifth sensor 8c to the display device 9.

[0077] The display device 9 determines the direction and degree of curvature of the base member 3 in the region A and the region B1 based on the signal input from the distance displacement sensor 8, and displays it on the display section 9a.

[0078] <Application to balloon catheters> Next, an example of application of the above-mentioned curvature detection system to a balloon catheter will be described. In particular, a balloon catheter to which the curvature detection system of the second embodiment is applied will be described. Fig. 14 is a diagram showing the overall configuration of a catheter system including a balloon catheter.

[0079] 14 includes a balloon catheter 21, a heating device 70, a supply device 74, and a stirring device 75 connected to the balloon catheter 21. The balloon catheter 21 also includes a catheter body 22 having a longitudinal direction LD, and a handle 50 connected to the proximal end of the catheter body 22.

[0080] 15, the catheter main body 22 of this application example has a balloon 25, an outer cylindrical shaft 30 connected to the proximal end 25b of the balloon 25, an inner cylindrical shaft 35 connected to the distal end 25a of the balloon 25, and a heating member 40 disposed within the balloon 25. The inner cylindrical shaft 35 passes through the outer cylindrical shaft 30 and extends into the balloon 25. A liquid delivery path LP leading to the inside of the balloon 25 is formed between the outer cylindrical shaft 30 and the inner cylindrical shaft 35. The heating member 40 is for heating the liquid within the balloon 25.

[0081] The longitudinal direction LD of the catheter main body 22 is specified as the direction in which the central axes 30X, 35X of the outer cylindrical shaft 30 and the inner cylindrical shaft 35 extending from the outer cylindrical shaft 30 extend. In this specification, the "distal" side used for each configuration of the balloon catheter 21 and the catheter main body 22 means the side away from the operator (surgeon) of the handle 50 and the balloon catheter 21 along the longitudinal direction LD of the catheter main body 22, in other words, the tip side. In addition, the "proximal" side used for each configuration of the balloon catheter 21 and the catheter main body 22 means the side close to the operator (surgeon) of the handle 50 and the balloon catheter 21 along the longitudinal direction LD of the catheter main body 22, in other words, the base end side.

[0082] The balloon catheter 21 will be described in more detail below. First, the catheter body 22 of the balloon catheter 21 will be described in detail. As described above, the catheter body 22 of the balloon catheter 21 according to this embodiment has the balloon 25, the outer cylindrical shaft 30, the inner cylindrical shaft 35, and the heating member 40. Furthermore, the catheter body 22 of this embodiment has a temperature sensor 45 disposed in the internal space of the balloon 25.

[0083] Among these, the outer tube shaft 30 and the inner tube shaft 35 are both configured to be tubular, typically cylindrical. Therefore, the outer tube shaft 30 and the inner tube shaft 35 each form a lumen as an internal space. For example, a guide wire (not shown) is inserted into the lumen formed by the inner tube shaft 35. The inner tube shaft 35 is inserted into the lumen formed by the outer tube shaft 30. That is, the outer tube shaft 30 and the inner tube shaft 35 have a double tube shaft configuration. The inner diameter of the outer tube shaft 30 is larger than the outer diameter of the inner tube shaft 35. Therefore, a lumen remains between the outer tube shaft 30 and the inner tube shaft 35. This lumen between the outer tube shaft 30 and the inner tube shaft 35 forms a liquid feed path LP. As shown in FIG. 15, the liquid feed path LP is connected to the inside of the balloon 25. In addition, the liquid feed path LP extends into the handle 50.

[0084] The length of the outer tube shaft 30 and the inner tube shaft 35 is preferably 500 mm or more and 1700 mm or less, and more preferably 600 mm or more and 1200 mm or less. The outer tube shaft 30 and the inner tube shaft 35 are preferably made of a flexible material having excellent antithrombotic properties. Examples of the flexible material having excellent antithrombotic properties include, but are not limited to, fluoropolymers, polyamides, polyurethane polymers, and polyimides. In addition, the outer tube shaft 30 is preferably made by laminating layers of different flexible materials in order to achieve both slidability with the inner tube shaft 35 and adhesiveness or heat welding with the balloon 25.

[0085] The outer diameter of the outer cylindrical shaft 30 is preferably 3.0 mm or more and 5.0 mm or less. The inner diameter of the outer cylindrical shaft 30 is preferably 2.0 mm or more and 4.0 mm or less. The outer diameter of the inner cylindrical shaft 35 is preferably 1.0 mm or more and 3.0 mm or less. The inner diameter of the inner cylindrical shaft 35 is preferably 0.5 mm or more and 2.0 mm or less.

[0086] A balloon 25 is connected to the outer cylindrical shaft 30 and the inner cylindrical shaft 35. The balloon 25 is formed so as to be expandable by filling with liquid and contractable by discharging the liquid. The balloon 25 preferably has a shape that can fit a target site (e.g., blood vessel) to be treated. As an example, a spherical shape with a diameter of 15 mm to 40 mm can be adopted as the shape of the balloon 25 that fits the pulmonary vein junction of the left atrium. Here, the spherical shape includes a perfect sphere, an oblate spheroid, and an oblong spheroid, and further includes a substantially spherical shape.

[0087] The thickness of the balloon 25 is preferably 20 μm or more and 100 μm or less. The material of the balloon 25 is preferably a stretchable material with excellent antithrombotic properties, and specifically, a polyurethane-based polymer material or the like can be used. Examples of polyurethane-based polymer materials used for the balloon 25 include thermoplastic polyether urethane, polyether polyurethane urea, fluorine polyether urethane urea, polyether polyurethane urea resin, and polyether polyurethane urea amide.

[0088] In the illustrated catheter main body 22, as shown in Figs. 14 and 15, the distal end (tip) 25a of the balloon 25 is fixed to the distal end (tip) 35a of the inner cylindrical shaft 35. The proximal end (base end) 25b of the balloon 25 is fixed to the distal end (tip) 30a of the outer cylindrical shaft 30. In the illustrated example, the distal end 30a of the outer cylindrical shaft 30 does not extend into the balloon 25. However, this is not limited to the illustrated example, and the distal end 30a of the outer cylindrical shaft 30 may extend into the balloon 25. The balloon 25, the outer cylindrical shaft 30, and the inner cylindrical shaft 35 can be connected to each other by bonding or heat welding.

[0089] The balloon 25 connected to the outer tube shaft 30 and the inner tube shaft 35 is deformed by the relative movement of the outer tube shaft 30 and the inner tube shaft 35 in the longitudinal direction LD. In the illustrated example, the size of the balloon 25 in the longitudinal direction LD can be adjusted by the relative movement of the outer tube shaft 30 and the inner tube shaft 35. As shown in FIG. 16, the balloon 25 is stretched in the longitudinal direction LD by the inner tube shaft 35 moving distally in the longitudinal direction LD relative to the outer tube shaft 30, and is in a further tensed state. In the illustrated example, the movement range of the inner tube shaft 35 to the distal side in the longitudinal direction LD relative to the outer tube shaft 30 is restricted by the balloon 25. The balloon 25 is in a relaxed state by the inner tube shaft 35 moving proximally in the longitudinal direction LD relative to the outer tube shaft 30 from the state shown in FIG. 16. By introducing liquid into the inside of the relaxed balloon 25, the balloon 25 can be inflated as shown in FIG. 15. That is, the size of the balloon 25 in the longitudinal direction LD can be adjusted by moving the outer cylindrical shaft 30 and the inner cylindrical shaft 35 relative to each other.

[0090] Next, the heating member 40 will be described. The heating member 40 is disposed inside the balloon 25. The heating member 40 is a member for heating the liquid filled in the balloon 25. As an example, a nichrome wire that generates heat by electrical resistance can be used as the heating member 40. As another example of the heating member 40, a coil electrode 41 can be used as shown in Figs. 15 and 16. By applying high-frequency current to the heating member 40 as the coil electrode 41, a high-frequency current flows between the coil electrode 41 and a counter electrode 77 (Fig. 14) disposed outside, and the liquid located between the coil electrode 41 and the counter electrode 77 generates Joule heat. The counter electrode 77 is disposed, for example, on the back of the patient.

[0091] In the example shown in FIG. 15 and FIG. 16, the coil electrode 41 is provided on the inner cylindrical shaft 35 extending inside the balloon 25. The coil electrode 41 may be formed of a conductive wire wound around the inner cylindrical shaft 35. The coil electrode 41 is electrically connected to the wiring 42 for high-frequency current flow. The wiring 42 extends to the handle 50 through the liquid transfer path LP as a lumen between the outer cylindrical shaft 30 and the inner cylindrical shaft 35. As a specific example of the coil electrode 41 constituting the heating member 40, a coil electrode can be adopted in which the insulation-coated lead wire used for the wiring 42 is stripped of its coating and wound around the inner cylindrical shaft 35. Such a coil electrode 41 can effectively suppress the occurrence of defects such as disconnection because it is integrally formed with the wiring 42.

[0092] The diameter of the coil electrode 41 and the wiring 42 is preferably 0.1 mm or more and 1 mm or less, and more preferably 0.1 mm or more and 0.4 mm or less. Examples of conductive materials constituting the coil electrode 41 and the wiring 42 include copper, silver, gold, platinum, and alloys thereof. It is preferable that the wiring 42 has a configuration in which the conductive linear portion is covered with an insulating film such as a fluoropolymer to prevent short circuits.

[0093] Next, the temperature sensor 45 will be described. The temperature sensor 45 is disposed in the internal space of the balloon 25, and acquires information regarding the temperature of the liquid in the balloon 25. In the illustrated example, the temperature sensor 45 has a heat-sensing unit 46 disposed in the vicinity of the heating member 40. This temperature sensor 45 can acquire information regarding the temperature of the liquid located in the vicinity of the heating member 40. By applying electrical energy to the heating member 40 based on the information acquired by the temperature sensor 45, the liquid around the heating member 40 can be heated to an appropriate temperature.

[0094] A thermocouple or a thermistor can be used as the temperature sensor 45. Information about temperature acquired by the temperature sensor 45 is, for example, a potential that can be acquired from a thermocouple or a resistance value that can be acquired from a thermistor.

[0095] 15 and 16, the temperature sensor 45 typically has a heat-sensing part 46 and a lead wire 47 electrically connected to the heat-sensing part 46. In the temperature sensor 45 as a thermocouple, the part where the dissimilar metals are connected forms the heat-sensing part 46. In the temperature sensor 45 as a thermistor, a ceramic element forms the heat-sensing part 46. The lead wire 47 extends to the handle 50 through the liquid sending path LP as a lumen between the outer cylindrical shaft 30 and the inner cylindrical shaft 35.

[0096] The diameter of the lead wire 47 is preferably 0.05 mm or more and 0.5 mm or less, and more preferably 0.05 mm or more and 0.3 mm or less. The temperature sensor 45 as a thermocouple can be formed by, for example, using constantan for the lead wire 47 and copper for the wiring 42 for high-frequency current application, and joining the two. In this example, the heat-sensing part 46 formed by joining the lead wire 47 and the wiring 42 can function as a thermocouple. The lead wire 47 is preferably provided with an electrically insulating coating such as fluoropolymer or enamel to prevent a short circuit with the wiring 42.

[0097] Next, the handle 50 connected to the above-described catheter main body 22 from the proximal side will be described. The handle 50 is a portion that is held by an operator (surgeon) while using the balloon catheter system 20. Therefore, it is preferable that the handle 50 has a design that allows the operator to easily hold and operate it with his or her hand. In addition, the material that constitutes the handle 50 is preferably a material with high chemical resistance, and for example, polycarbonate or ABS resin can be used.

[0098] 14 has a first handle portion 51 and a second handle portion 52 which are slidable relative to each other. The first handle portion (front handle portion) 51 is connected to the outer cylindrical shaft 30 of the catheter body 22. The second handle portion (rear handle portion) 52 is connected to the inner cylindrical shaft 35 of the catheter body 22. By moving the second handle portion 52 relative to the first handle portion 51, the inner cylindrical shaft 35 can be moved relative to the outer cylindrical shaft 30.

[0099] As shown in FIG. 14, the handle 50 also functions as a portion for connecting the balloon catheter 21 to other devices included in the balloon catheter system 20.

[0100] First, the connector 56 extends from the second handle portion 52. This connector 56 electrically connects the wiring 42 and the lead wire 47 to an external heating device 70. The connector 56 extends from one 52a of a plurality of branch portions 52a, 52b, 52c provided on the second handle portion 52.

[0101] The connector 56 is preferably configured to effectively prevent erroneous connection. The connector 56 is also preferably highly waterproof. The configuration of the connector 56 can be determined taking into consideration the convenience of the surgeon and design considerations. The connector 56 is also preferably made of a material having high chemical resistance, similar to the handle 50, and suitable examples include polycarbonate or ABS resin.

[0102] The connector 56 may have a high conductivity metal pin inside. The wiring 42 and the lead wire 47 may be electrically connected to the heating device 70 as a high frequency power supply means by connecting to this high conductivity metal pin. However, the lead wire 47 may be electrically connected to a device other than the heating device 70 as a high frequency power supply means, for example, a temperature indicator. The material of the high conductivity metal pin included in the connector 56 is not particularly limited as long as it is a metal with high conductivity. Examples of the high conductivity metal pin included in the connector 56 include copper, silver, gold, platinum, and alloys thereof. In addition, it is preferable that the outside of the high conductivity metal pin is protected by an electrically insulating and chemically resistant material. Examples of the electrically insulating and chemically resistant material include polysulfone, polyurethane polymer, polypropylene, and polyvinyl chloride.

[0103] The second handle portion 52 has branches 52b and 52c other than the branch 52a to which the connector 56 is connected. These branches 52b and 52c function as portions for supplying liquid to the lumen, which is the internal space of the inner cylindrical shaft 35, and as portions from which a guide wire inserted into the lumen of the inner cylindrical shaft 35 extends. During cardiac ablation treatment, it is common to eject a small amount of physiological saline solution, about 100 ml per hour, into the body through the lumen of the inner cylindrical shaft 35. By ejecting physiological saline solution, backflow of blood into the lumen of the inner cylindrical shaft 35 can be effectively prevented.

[0104] 14, an extension tube 57 extends from the first handle portion 51. The extension tube 57 connects the liquid feed path LP of the catheter main body 22 to an external supply device 74 or agitator 75. The extension tube 57 extends from a branch portion 51a provided in the first handle portion 51. The extension tube 57 is connected to the supply device 74 and the agitator 75 via a valve 58. In the illustrated example, by operating the valve 58, it is possible to select whether the supply device 74 or the agitator 75 is to be connected to the liquid feed path LP. A three-way stopcock can be used as the valve 58.

[0105] Next, the devices constituting the balloon catheter system 20 together with the balloon catheter 21 described above, specifically, the heating device 70, the supply device 74, and the stirring device 75, will be described.

[0106] The illustrated heating device 70 is electrically connected to the coil electrode 41 via the connection cable 56a and the wiring 42. High-frequency power generated by the heating device 70 is supplied to the coil electrode 41 via the connection cable 56a and the wiring 42. The heating device 70 has a high-frequency current control unit 71 that controls high-frequency current to the coil electrode 41. In the illustrated example, the high-frequency current control unit 71 controls high-frequency current to the coil electrode 41, thereby adjusting the output from the heating member 40. In addition, the high-frequency current control unit 71 is electrically connected to the connection cable 56a and the lead wire 47, and can control high-frequency current to the coil electrode 41 based on information on the temperature of the liquid in the balloon 25 acquired by the temperature sensor 45.

[0107] The heating device 70 is configured with hardware such as a CPU. The high-frequency current control unit 71 and one or more of the other components included in the heating device 70 may be configured as separate hardware. At least a part of the heating device 70 may be configured with software. A part of the heating device 70 may be physically located separately. In addition, some of the components of the heating device 70 may be capable of coordinating with other components by communication through a network. In addition, some of the components of the heating device 70 may be on a device that can communicate with other components through an external network, such as a server or database on a cloud.

[0108] Next, the supply device 74 will be described. The supply device 74 supplies liquid into the liquid feed path LP. The supply device 74 can inflate the balloon 25 as shown in FIG. 15 by supplying liquid to the balloon 25 through the liquid feed path LP. On the other hand, the supply device 74 can also deflate the balloon 25 by discharging liquid from the balloon 25 through the liquid feed path LP. As the supply device 74, a syringe can be used as shown in the figure. However, a pump or the like can also be used as the supply device 74. Note that the liquid supplied into the liquid feed path LP is preferably a contrast agent or a contrast agent diluted with saline so that the balloon 25 inflated with the liquid can be confirmed in an X-ray fluoroscopic image.

[0109] Next, the stirring device 75 will be described. The stirring device 75 is provided to stir the liquid in the balloon 25. By stirring the liquid in the balloon 25, the liquid heated by the heating member 40 can be diffused to uniformize the temperature of the liquid in the balloon 25, and as a result, the surface temperature of the balloon 25 can be adjusted. The stirring device 75 repeatedly supplies liquid to the liquid feed path LP and discharges liquid from the liquid feed path LP. As a result, the liquid is repeatedly supplied from the liquid feed path LP to the inside of the balloon 25 and discharged from the inside of the balloon 25 to the liquid feed path LP, and the liquid in the balloon 25 is stirred. As the stirring device 75, a pump selected from the group consisting of a roller pump, a diaphragm pump, a bellows pump, a vane pump, a centrifugal pump, and a pump consisting of a combination of a piston and a cylinder can be adopted.

[0110] The amount of liquid supplied to the liquid sending path LP and the amount of liquid discharged from the liquid sending path LP can be a constant amount (e.g., 0.5 ml to 1.5 ml). The supply of liquid to the liquid sending path LP and the discharge of liquid from the liquid sending path LP may be repeated at a constant cycle (e.g., 1 to 3 times per second). The amount of liquid supplied to the liquid sending path LP and the amount of liquid discharged from the liquid sending path LP may be adjusted by a control signal from an agitation control device (not shown) or by direct input from an operator. Similarly, the cycle of the supply of liquid to the liquid sending path LP and the discharge of liquid from the liquid sending path LP may be adjusted by a control signal from an agitation control device (not shown) or by direct input from an operator.

[0111] In order to adjust the surface temperature of the balloon 25 to an ideal temperature, it is necessary to efficiently diffuse the liquid heated by the heating member 40 in the balloon 25. In order to efficiently diffuse the heated liquid, it is desirable that most (or all) of the liquid flowing into the balloon 25 from the liquid feed path LP heads toward the heating member 40 when the stirring device 75 supplies the liquid from the liquid feed path LP into the balloon 25. However, if the inner cylindrical shaft 35 is curved due to the application of a pressing force to the balloon 25 during treatment, the alignment direction of the distal end 30a of the outer cylindrical shaft 30 and the heating member 40 may be significantly deviated from the discharge direction of the liquid discharged from the distal end 30a of the outer cylindrical shaft 30 (the direction along the central axis 30X of the outer cylindrical shaft 30 at the distal end 30a). Even if liquid is supplied into the balloon 25 in this state, most or all of the liquid flowing into the balloon 25 from the liquid feed path LP does not head toward the heating member 40, and most or all of the heated liquid near the heating member 40 cannot be diffused. As a result, the surface temperature of the balloon 25 cannot be increased as desired. In addition, since the temperature of the liquid near the temperature sensor 45 is maintained high, even if the surface temperature of the balloon 25 has not yet reached the desired temperature, the supply of electrical energy from the heating device 70 to the heating member 40 may be insufficient, and the surface temperature of the balloon 25 may not be increased to the desired temperature. In this way, if the liquid heated by the heating member 40 cannot be efficiently diffused, it is difficult to adjust the surface temperature of the balloon 25 to an ideal temperature.

[0112] 19 shows a balloon catheter 21 in which a balloon 25 is pressed perpendicularly against the opening surface of a pulmonary vein orifice 99a of a simulated living organism 99. In the example shown in FIG. 19, the direction of the force applied to the balloon 25 is along the central axis 30X at the distal end 30a of the outer cylindrical shaft 30. The inner cylindrical shaft 35 is not curved between the distal end 30a of the outer cylindrical shaft 30 and the heating member 40, and the distal end 30a of the outer cylindrical shaft 30 and the heating member 40 are aligned in the discharge direction of the liquid discharged from the distal end 30a of the outer cylindrical shaft 30 (the direction along the central axis 30X of the outer cylindrical shaft 30 at the distal end 30a).

[0113] 20 shows a balloon catheter 21 in which the balloon 25 is pressed against the opening surface of the pulmonary vein orifice 99a of the simulated living organism 99 at an angle of 45 degrees to 60 degrees. In the example shown in FIG. 20, the direction of the force applied to the balloon 25 is a direction intersecting the direction along the central axis 30X at the distal end 30a of the outer cylindrical shaft 30. The inner cylindrical shaft 35 is curved significantly between the distal end 30a of the outer cylindrical shaft 30 and the heating member 40, and the distal end 30a of the outer cylindrical shaft 30 and the heating member 40 are not aligned with the discharge direction of the liquid discharged from the distal end 30a of the outer cylindrical shaft 30.

[0114] 19 and 20, the flow (agitation flow) of liquid discharged from the distal end 30a of the outer cylindrical shaft 30 into the balloon 25 is indicated by arrows.

[0115] As can be seen from FIG. 19, when the inner cylindrical shaft 35 is not curved between the distal end 30a of the outer cylindrical shaft 30 and the heating member 40, most of the liquid discharged from the liquid feed path LP into the balloon 25 moves toward the heating member 40 while surrounding the inner cylindrical shaft 35. Then, while diffusing most of the heated liquid near the heating member 40, it newly surrounds the heating member 40. The diffused liquid moves toward the surface of the balloon 25 and heats the surface of the balloon 25. The liquid newly surrounding the heating member 40 is heated by the heating member 40. In the example shown in FIG. 19, the liquid heated by the heating member 40 is evenly dispersed in the balloon 25, and the inside of the balloon 25 and the surface of the balloon 25, i.e., the regions indicated by h, i, j, and k in the figure, are generally at approximately the same temperature. In addition, since the liquid heated by the heating member 40 is efficiently diffused, it is easy to adjust the surface temperature of the balloon 25 to a desired temperature by adjusting the supply of electrical energy to the heating member 40. As a result, ablation treatment can be performed effectively.

[0116] On the other hand, as can be seen from FIG. 20, when the inner cylindrical shaft 35 is greatly curved between the distal end 30a of the outer cylindrical shaft 30 and the heating member 40, the liquid discharged from the liquid delivery path LP into the balloon 25 deviates from the heating member 40 and heads toward the surface of the balloon 25 without being heated by the heating member 40. For this reason, the liquid heated by the heating member 40 cannot be efficiently diffused. Specifically, most (or all) of the liquid heated by the heating member 40 cannot be diffused by agitation flow. Alternatively, the heated liquid cannot be uniformly dispersed within the balloon 25. As a result, the conduction of heat generated by the heating member 40 depends on the thermal radiation within the balloon 25, and the temperature of the entire balloon 25 becomes low and unstable. Alternatively, the surface temperature of the balloon 25 is biased. For example, when the liquid flows within the balloon 25 as shown in FIG. 20, there is a risk that the temperatures of the surface regions i and h will be lower than the temperatures of the regions indicated by symbols j and k. For this reason, it is difficult to adjust the surface temperature of the balloon 25 to a desired temperature. As a result, ablation therapy cannot be performed as desired.

[0117] Here, in general, the operation of the balloon catheter is performed while observing an X-ray fluoroscopic image of the tip of the balloon catheter. The X-ray fluoroscopic image is a two-dimensional image. For this reason, it is difficult to grasp the curvature of the tip of the balloon catheter based on the X-ray fluoroscopic image. Or, even if the curvature can be grasped, it is difficult to grasp the direction and degree of the curvature. In addition, in general, in order to always be able to grasp the curvature direction and degree of the curvature of the balloon catheter during the procedure, it is necessary to obtain the X-ray fluoroscopic image as a moving image, but in this case, there is a problem in that the amount of exposure to X-rays increases.

[0118] Considering these points, in the balloon catheter 21 of this embodiment, as shown in Figs. 17 to 18C, the base member 12 with curvature detection function shown in Figs. 7 to 12 is used as the inner tubular shaft 35. This allows the surgeon to always easily grasp the curvature state (curvature direction and degree of curvature) of the inner tubular shaft 35. Note that Fig. 17 shows only the first linear member 6 and the second linear member 7 out of the linear members 6, 7, 16, and 17. Also, Fig. 17 omits the illustration of the lumens 4a, 4b, 4c, and 4d.

[0119] In the illustrated example, one end of the base member 3 of the base member 12 with a curvature detection function is the proximal end of the inner cylindrical shaft 35, and the other end is the distal end of the inner cylindrical shaft 35. The first fixing position P1 is located at a position overlapping the proximal end 40b of the heating member 40 when viewed in the radial direction of a circle centered on the central axis X of the base member 3 (the central axis 35X of the inner cylindrical shaft 35). The second fixing position P2 is located at a position overlapping the distal end 35a of the outer cylindrical shaft 30 when the balloon 25 is inflated when viewed in the radial direction of a circle centered on the central axis X of the base member 3. With such an inner cylindrical shaft 35, the curvature of the inner cylindrical shaft 35 between the heating member 40 and the distal end 30a of the outer cylindrical shaft 30 can be constantly grasped while the balloon 25 is inflated to cauterize the target site. Then, the balloon catheter 21 can be operated based on the grasped curved state of the inner cylindrical shaft 35 (curved direction and degree of curvature) to correct the posture of the tip of the inner cylindrical shaft 35.

[0120] In particular, in the illustrated example, the balloon catheter system 20 includes distance displacement sensors 8, 18 connected to the linear members 6, 7, 16, 17 of the inner cylindrical shaft 35, and a display device 9 that receives signal input from the distance displacement sensors 8, 18. Therefore, the surgeon can grasp the state of curvature of the inner cylindrical shaft 35 by looking at the display units 9a, 9b of the display device 9. Note that, of the distance displacement sensors 8, 18 of the inner cylindrical shaft 35, only the distance displacement sensor 8 is shown in FIG. 17. The distance displacement sensors 8, 18 of the inner cylindrical shaft 35 are electrically connected to the display device 9 via a connector 56.

[0121] 17 to 18C, the base member 12 with a curvature detection function shown in Figs. 7 to 12 is used as the outer cylindrical shaft 35. This allows the surgeon to constantly grasp the curvature state (curvature direction and degree of curvature) of the outer cylindrical shaft 30.

[0122] In the illustrated example, one end of the base member 3 of the base member 12 with the curvature detection function is the proximal end of the outer cylindrical shaft 30, and the other end is the distal end of the outer cylindrical shaft 30. The first fixing position P1 of the outer cylindrical shaft 30 is at the distal end of the outer cylindrical shaft 30. The second fixing position P2 of the outer cylindrical shaft 30 is on the proximal end side of the distal end 30a of the outer cylindrical shaft 30. The distance between the first fixing position P1 and the second fixing position P2 of the outer cylindrical shaft 30 is, for example, 1 mm or more and 150 mm or less. With such an outer cylindrical shaft 30, the curvature near the distal end 30a of the outer cylindrical shaft 30 can be constantly detected, and based on this, the pressing direction of the balloon 25 against the target site can be constantly grasped. Then, based on the grasped state of curvature of the outer cylindrical shaft 30 (direction of curvature and degree of curvature), the balloon catheter 21 can be operated to correct the posture of the tip of the outer cylindrical shaft 30 and the direction in which the balloon 25 is pressed against the target site.

[0123] In particular, in the illustrated example, the balloon catheter system 20 includes distance displacement sensors 8, 18 connected to the linear members 6, 7, 16, 17 of the outer cylindrical shaft 30, and a display device 9 that receives signal input from the distance displacement sensors 8, 18. Therefore, the surgeon can grasp the curvature state of the outer cylindrical shaft 30 by looking at the display units 9a, 9b of the display device 9. Note that, of the distance displacement sensors 8, 18 of the outer cylindrical shaft 30, only the distance displacement sensor 8 is shown in FIG. 17. The distance displacement sensors 8, 18 of the outer cylindrical shaft 30 are electrically connected to the display device 9 via a connector 56.

[0124] When the base member 12 with curvature detection function is used as the inner tubular shaft 35 and / or the outer tubular shaft 30 of the balloon catheter 21, the diameter of the linear members 6, 7, 16, 17 is preferably 0.1 mm or more and 0.5 mm or less. In this case, the linear members 6, 7, 16, 17 may be made of a metal wire made of a metal that is resistant to corrosion, such as SUS304 or nickel, or a resin monofilament that has low elasticity and high strength.

[0125] Next, an example of a method of using the balloon catheter system 20 configured as above will be described.

[0126] First, the inner cylindrical shaft 35 is moved relative to the outer cylindrical shaft 30 toward the distal side (tip side) in the longitudinal direction LD to stretch the balloon 25 as shown in Fig. 16. At this time, the outer cylindrical shaft 30 and the inner cylindrical shaft 35 can be moved relatively by operating the first handle portion 51 and the second handle portion 52 of the handle 50. Then, the catheter main body 22 with the balloon 25 stretched is inserted into the body. When the catheter main body 22 is inserted into the body, the balloon 25 is not filled with liquid.

[0127] When the distal end of the catheter body 22 is guided to the vicinity of the target site (affected area), the inner cylindrical shaft 35 is moved proximally (toward the base end) in the longitudinal direction LD relative to the outer cylindrical shaft 30 to relax the balloon 25. Next, the valve 58 is operated to connect the supply device 74 to the liquid feed path LP of the catheter body 22 via the handle 50. Thereafter, the supply device 74 is operated to feed liquid into the liquid feed path LP, and the balloon 25 is inflated with the liquid, as shown in FIG.

[0128] Next, the valve 58 is operated to cut off the supply device 74 from the liquid feed path LP and connect the agitator 75 to the liquid feed path LP. The agitator 75 is controlled by a control signal from an agitation control device (not shown) and repeatedly supplies a certain amount of liquid to the liquid feed path LP and discharges a certain amount of liquid from the liquid feed path LP at a certain period. As a result, the discharge of a certain amount of liquid from the liquid feed path LP into the balloon 25 and the suction of a certain amount of liquid from the balloon 25 to the liquid feed path LP are repeatedly performed at a certain period, and the liquid in the balloon 25 is agitated.

[0129] In addition, the heating member 40 is controlled by a high-frequency current control unit 71 of the heating device 70 to adjust the liquid temperature in the balloon 25. Specifically, high-frequency current is applied from the heating device 70 between the coil electrode 41 of the heating member 40 and a counter electrode 77 arranged outside the patient's body. As a result, a high-frequency current is generated between the coil electrode 41 and the counter electrode 77.

[0130] In this manner, the liquid in the balloon 25 is heated and stirred. Then, the balloon 25 containing the heated liquid is pressed against a target site, and the target site is ablated.

[0131] During ablation, the catheter body 22 is operated to correct the pressing direction of the balloon 25 against the target site while checking the curved state of the outer cylindrical shaft 30 near the distal end 30a displayed on the display parts 9a and 9b of the display device 9. Also, while checking the curved state of the inner cylindrical shaft 35 between the coil electrode 41 and the distal end 30a of the outer cylindrical shaft 30 displayed on the display parts 9a and 9b of the display device 9, the catheter body 22 is operated to align the alignment direction of the coil electrode 41 and the distal end 30a of the outer cylindrical shaft 30 with the extension direction of the central axis 30X of the outer cylindrical shaft 30 at the distal end 30a of the outer cylindrical shaft 30.

[0132] By using such a balloon catheter 21, the surgeon can easily press the balloon 25 against the target site in an appropriate direction. In addition, it is easy to correct the attitude of the tip of the inner cylindrical shaft 35 so that the liquid in the balloon 25 is effectively stirred, and it is easy to adjust the surface temperature of the balloon 25, which is the most important factor during ablation treatment, to an ideal temperature. As a result, the effect of ablation treatment can be dramatically improved.

[0133] When ablation of the target site is completed, the energy supply to the heating member 40 is stopped. In addition, the valve 58 is operated to connect the supply device 74 to the liquid feed path LP of the catheter main body 22 via the handle 50, and the agitator 75 is disconnected from the liquid feed path LP. Then, the supply device 74 is used to discharge liquid from the liquid feed path LP, and the balloon 25 is deflated. Next, the second handle portion 52 is operated to expand the deflated balloon 25 as shown in FIG. 16. Then, the catheter main body 22 with the balloon 25 expanded is removed from the body. This completes the treatment using the balloon catheter system 20.

[0134] 1 to 18C and 19 to 20, the base member 2, 12, 102 with curvature detection function, the curvature detection system 1, 11, 101, and the balloon catheter system 20 to which the curvature detection system 1, 11, 101 is applied according to the present embodiment have been described above, but the configurations of the base member 2, 12, 102 with curvature detection function, the curvature detection system 1, 11, 101, and the balloon catheter system 20 are not limited to those described above. Various modifications can be made to the configurations of the base member 2, 12, 102 with curvature detection function, the curvature detection system 1, 11, 101, and the balloon catheter system 20 shown in Figs. 1 to 18C.

[0135] For example, in the examples shown in Figs. 1 to 18C, the first linear member 6 and the second linear member 7 are disposed in different lumens 4a and 4b, but may be disposed in the same lumen. The first linear member 6 and the second linear member 7 do not have to be disposed in the lumens 4a and 4b, but may be disposed on the surface of the base member 3. In the examples shown in Figs. 7 to 12 and Figs. 14 to 18C, the third linear member 16 and the fourth linear member 17 are disposed in different lumens 4c and 4d, but may be disposed in the same lumen. The third linear member 16 and the fourth linear member 17 do not have to be disposed in the lumens 4c and 4d, but may be disposed on the surface of the base member 3. In the example shown in Fig. 13, the fifth linear member 108 is disposed in a lumen 4e different from the lumens 4a and 4b of the first linear member 6 and the second linear member 7, but the linear members 6, 7, and 108 may be disposed in the same lumen. Furthermore, the linear members 6, 7, and 108 do not necessarily have to be disposed inside the lumens 4a, 4b, and 4e, and may be disposed on the surface of the base member 3.

[0136] 7 to 12 and 14 to 18C, the display device 9 separates the curvature direction of the base member 3 into an up-down direction and a left-right direction and displays them as two pieces of information, but is not limited to this. The display device 9 may perform an operation on the signal input from the distance displacement sensor 8 and the signal input from the second distance displacement sensor 18, and display the curvature direction of the base member 3 in the up-down direction and the curvature direction in the left-right direction as a single curvature direction combined together. This allows the surgeon to more easily grasp the curvature direction of the base member 3.

[0137] 1 to 18C, the display device 9 indicates the curvature direction and the degree of curvature of the base member 3 with characters, but is not limited to this. The display device 9 may indicate the curvature direction with an image, a diagram, a vector, or the like. In particular, when the curvature direction of the base member 3 is displayed as a single curvature direction that combines the curvature direction in the up-down direction and the curvature direction in the left-right direction of the base member 3, it is preferable that the display device 9 indicates the curvature direction with an image, a diagram, or a vector.

[0138] In the example shown in Figs. 1 to 18C, the change in the relative position of the second end portions 6b, 7b; 16b, 17b; 6b, 7b, 108b is detected by the distance displacement sensors 8, 18, but this is not limiting. For example, the change in the relative position of the second end portions 6b, 7b; 16b, 17b; 6b, 7b, 108b may be grasped by a pressure sensor. In this case, the change in the relative position of the second end portions 6b, 7b; 16b, 17b; 6b, 7b, 108b may be detected by detecting the difference in the tensile force or pressing force received from the linear members 6, 7; 16, 17; 6, 7, 108. In addition, a proximity sensor or the like may be adopted as a sensor for detecting the change in the relative position of the second end portions 6b, 7b; 16b, 17b; 6b, 7b, 108b.

[0139] Furthermore, the change in the relative position of the second end portions 6b, 7b; 16b, 17b may be grasped by providing markers on the surfaces of the linear members 6, 16 and the linear members 7, 17 and visually confirming the change in the relative position of the markers provided on the linear members 6, 16 and the markers provided on the linear members 7, 17. One of the markers may be a distance measuring scale capable of measuring the distance of the relative movement of the other marker. These markers may also be provided on other members fixed to the linear members 6, 16 and the linear members 7, 17. The change in the relative position of the second end portions 17b, 108b may also be grasped by using the markers in a similar manner.

[0140] Furthermore, the curvature detection system 1, 11, 101 may include an alarm that issues an alarm to notify the occurrence of curvature.

[0141] The application of the curvature detection system 1, 11, 101 and the base member 2, 12, 102 with a curvature detection function described above is not limited to balloon catheters. The base member 2, 12, 102 with a curvature detection function can also be applied to other types of catheters and other medical devices such as medical endoscopes. Furthermore, the base member 2, 12, 102 with a curvature detection function can also be applied to devices other than medical devices, such as industrial endoscopes.

[0142] In the first to third embodiments described above, the base member 2, 12, 102 with a curvature detection function includes a base member 3 having a longitudinal direction LD, and a first linear member 6 and a second linear member 7 extending along the longitudinal direction LD. The first linear member 6 is fixed to the base member 3 at a first fixing position P1, and is movable in the longitudinal direction LD relative to the base member 3 on one side along the longitudinal direction LD from the first fixing position P1. The second linear member 7 is fixed to the base member 3 at a second fixing position P2 different from the first fixing position P1 in the longitudinal direction LD, and is movable in the longitudinal direction LD relative to the base member 3 on one side along the longitudinal direction LD from the second fixing position P2. Then, the curvature of the base member 3 between the first fixing position P1 and the second fixing position P2 can be detected according to a change in the relative position of the first linear member 6 and the second linear member 7.

[0143] In the first to third embodiments, the first linear member 6 and the second linear member 7 are disposed in lumens 4a, 4b provided in the base member 3. This reduces the risk that the linear members 6, 7 are damaged and the curvature of the base member 3 goes undetected.

[0144] In the first to third embodiments, the first linear member 6 and the second linear member 7 are disposed in different lumens 4a, 4b, which reduces the risk that the first linear member 6 and the second linear member 7 are entangled with each other, resulting in the curvature of the base member 3 not being detected.

[0145] In the first to third embodiments, the base member 3 is a tubular member having a wall portion 4 that defines a hollow portion. Since the base member 3 has such a shape, the base member 2 with a curvature detection function can be applied to catheters, endoscopes, etc.

[0146] In the first to third embodiments, the lumens 4a, 4b are formed in the wall portion 4. This makes it possible to suppress an increase in the dimensions of the base member 3 due to the formation of the lumens 4a, 4b.

[0147] In addition, in the modified example, markers indicating the relative positions of the first linear member 6 and the second linear member 7 are provided on the first linear member 6 and the second linear member 7. This makes it possible to easily grasp the curvature of the base member 3.

[0148] In the second embodiment, the third linear member 16 and the fourth linear member 17 extend along the longitudinal direction LD at positions different from the first linear member 6 and the second linear member 7 in the circumferential direction RD of the wall portion 4. The third linear member 16 is fixed to the base member 3 at the first fixing position P1, and is movable in the longitudinal direction LD relative to the base member 3 on one side along the longitudinal direction LD from the first fixing position P1. The fourth linear member 17 is fixed to the base member 3 at the second fixing position, and is movable in the longitudinal direction LD relative to the base member 3 on one side along the longitudinal direction LD from the second fixing position. Then, the curvature of the base member 3 between the first fixing position P1 and the second fixing position P2 can be detected according to the change in the relative positions of the third linear member 16 and the fourth linear member 17. In particular, the curvature in a direction different from the direction of the curvature detected according to the change in the relative positions of the first linear member 6 and the second linear member 7 can also be detected.

[0149] Specifically, in the second embodiment, the third linear member 16 and the fourth linear member 17 are disposed in separate lumens 4c, 4d that are provided at positions different from the lumens 4a, 4b in the circumferential direction RD of the wall portion 4. This reduces the risk that the linear members 6, 7 and the linear members 16, 17 become entangled, resulting in failure to detect curvature in the above two directions. In addition, because the linear members 16, 17 are disposed in the lumens 4c, 4d, it reduces the risk that the linear members 16, 17 are damaged, resulting in failure to detect curvature of the base member 3.

[0150] In addition, in the modified example, markers indicating the relative positions of the third linear member 16 and the fourth linear member 17 are provided on the third linear member 16 and the fourth linear member 17. This makes it possible to easily grasp the curvature of the base member 3.

[0151] Moreover, in the first to third embodiments, the curvature detection systems 1, 11, 101 include the above-mentioned base members 2, 12, 102 with curvature detection functions, and a sensor 8 that detects a change in the relative position of the first linear member 6 and the second linear member 7. According to such a curvature detection system 1, the curvature of the base member 3 can be easily grasped.

[0152] Moreover, in the second embodiment, the curvature detection system 11 includes the above-mentioned base member 12 with curvature detection function, a sensor 8 that detects a change in the relative position of the first linear member 6 and the second linear member 7, and a second sensor 18 that detects a change in the relative position of the third linear member 16 and the fourth linear member 17. According to such a curvature detection system 1, it is possible to easily grasp the curvature of the base member 3 in two different directions.

[0153] In addition, in the modified example, the device includes the above-mentioned curvature detection function-equipped base member 2, 12, 102. According to such a device, it is possible to detect the curvature of the base member 3 in a place that is difficult to visually observe, and the operability of the device is improved.

[0154] In the above-mentioned application example, the balloon catheter 21 includes the balloon 25, the catheter body 22, and the heating member 40. The catheter body 22 has an outer cylindrical shaft 30 connected to the proximal end 25b of the balloon 25, and an inner cylindrical shaft 35 extending into the balloon 25 and connected to the distal end 25a of the balloon 25. The inner cylindrical shaft 35 passes through the outer cylindrical shaft 30, and the gap between the inner cylindrical shaft 35 and the outer cylindrical shaft 30 forms a liquid feed path LP that leads to the internal space of the balloon 25. The heating member 40 is disposed on the outer circumferential surface of the inner cylindrical shaft 35 in the balloon 25 to heat the liquid in the balloon 25. The inner cylindrical shaft 35 is the base member 2, 12, 102 with the curvature detection function described above. According to such a balloon catheter 21, the curvature of the inner cylindrical shaft 35 disposed inside the body can be grasped, and the operability of the balloon catheter 21 is improved.

[0155] The present invention can be used in various devices, for example, in medical devices such as catheters, such as balloon catheters, for treating arrhythmias, such as atrial fibrillation, endometriosis, cancer, and the like, medical endoscopes, and industrial devices, such as industrial endoscopes. [Explanation of symbols]

[0156] REFERENCE SIGNS LIST 1, 11, 101...curvature detection system, 2, 12, 102...base member with curvature detection function, 3...base member, 3a...hollow portion, 4...wall portion, 4a, 4b, 4c, 4d, 4e...lumen, 6...first linear member, 7...second linear member, 16...third linear member, 17...fourth linear member, 108...fifth linear member, 20...balloon catheter system, 21...balloon catheter, 25...balloon, 30...outer cylindrical shaft, 35...inner cylindrical shaft, 40...heating member, 41...coil electrode, 45...temperature sensor, 70...heating device, 75...mixing device, LD...longitudinal direction, LP...liquid transfer path

Claims

1. A curvature detection system comprising a base member with a curvature detection function and a sensor, The base member with a curvature detection function is A base member having a longitudinal direction; a first linear member and a second linear member extending along the longitudinal direction, the first linear member is fixed to the base member at a first fixing position and is movable in the longitudinal direction relative to the base member on one side along the longitudinal direction of the first fixing position; the second linear member is fixed to the base member at a second fixed position different from the first fixed position in the longitudinal direction, and is movable in the longitudinal direction relative to the base member on one side along the longitudinal direction of the second fixed position, The sensor detects a change in a relative position between the first linear member and the second linear member, A curvature detection system capable of detecting curvature of the base member between the first fixed position and the second fixed position in response to a change in the relative position of the first linear member and the second linear member.

2. The curvature detection system according to claim 1 , wherein the first linear member and the second linear member are disposed within a lumen provided in the base member.

3. The curvature detection system according to claim 2 , wherein the first linear member and the second linear member are disposed in different lumens.

4. 4. The curvature detection system according to claim 1, wherein the base member is a cylindrical member having a wall portion that defines a hollow portion.

5. The first linear member and the second linear member are disposed within a lumen provided in the base member, The curvature detection system of claim 4 , wherein the lumen is formed in the wall portion.

6. The curvature detection system according to claim 1 , wherein markers indicating relative positions of the first linear member and the second linear member are provided on the first linear member and the second linear member.

7. the first linear member and the second linear member include a third linear member and a fourth linear member extending along the longitudinal direction at different positions in a circumferential direction of the wall portion, the third linear member is fixed to the base member at the first fixing position and is movable in the longitudinal direction relative to the base member on one side along the longitudinal direction of the first fixing position; the fourth linear member is fixed to the base member at the second fixing position and is movable in the longitudinal direction relative to the base member on one side along the longitudinal direction of the second fixing position, The curvature detection system according to claim 4 or 5, capable of detecting curvature of the base member between the first fixed position and the second fixed position in response to a change in the relative position of the third linear member and the fourth linear member.

8. The first linear member and the second linear member are disposed within a lumen provided in the base member, The curvature detection system according to claim 7 , wherein the third linear member and the fourth linear member are disposed in a separate lumen provided at a different position from the lumen in the circumferential direction of the wall portion.

9. The curvature detection system according to claim 7 , wherein markers indicating relative positions of the third linear member and the fourth linear member are provided on the third linear member and the fourth linear member.

10. A sensor for detecting a change in the relative position of the first linear member and the second linear member; a second sensor that detects a change in the relative position of the third linear member and the fourth linear member; The curvature detection system according to any one of claims 7 to 9, comprising:

11. Balloons and a catheter shaft having an outer cylindrical shaft connected to a proximal end of the balloon and an inner cylindrical shaft extending into the balloon and connected to a distal end of the balloon, the inner cylindrical shaft passing through the outer cylindrical shaft, and a gap between the inner cylindrical shaft and the outer cylindrical shaft forming a fluid supply path leading to an internal space of the balloon; a heating member disposed on an outer circumferential surface of the inner cylindrical shaft within the balloon for heating the liquid within the balloon; Equipped with The curvature detection system according to any one of claims 1 to 10, wherein the inner cylindrical shaft is a base member with a curvature detection function.

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