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US-12622575-B2 - Base member with curvature detection function, curvature detection system, device comprising base member with curvature detection function, and balloon catheter

US12622575B2US 12622575 B2US12622575 B2US 12622575B2US-12622575-B2

Abstract

A base member includes: a base member having a longitudinal direction; a first linear member extending in the longitudinal direction; and a second linear member extending in the longitudinal direction. The first linear member is fixed to the base member at a first position, and is movable with respect to the base member in the longitudinal direction, on one side of the first position in the longitudinal direction. The second linear member is fixed to the base member at a second position, and is movable with respect to the base member in the longitudinal direction, on the one side of the second position in the longitudinal direction. The base member is capable of detecting curvature of the base member between the first position and the second fixed position based on change in a relative position between the first linear member and the second linear member.

Inventors

  • Kosei Iwakawa

Assignees

  • TORAY INDUSTRIES, INC.

Dates

Publication Date
20260512
Application Date
20210331
Priority Date
20200331

Claims (9)

  1. 1 . A curvature detection system comprising: a base member having a longitudinal direction, wherein the base member is a cylindrical member having a wall delimiting a hollow; a first linear member extending in the longitudinal direction, wherein the first linear member is fixed to the base member at a first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on one side of the first fixed position in the longitudinal direction; a second linear member extending in the longitudinal direction, wherein the second linear member is fixed to the base member at a second fixed position different from the first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on the one side of the second fixed position in the longitudinal direction; a distance displacement sensor, wherein the sensor is configured to detect change in a relative position between the first linear member and the second linear member, thereby detecting curvature of the base member between the first fixed position and the second fixed position based on change in the relative position between the first linear member and the second linear member; a third linear member; and a fourth linear member, wherein the third and fourth linear members extend along the longitudinal direction at a position different from a position of the first linear member and the second linear member in a circumferential direction of the wall, the third linear member is fixed to the base member at the first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on the one side of the first fixed position in the longitudinal direction, the fourth linear member is fixed to the base member at the second fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on the one side of the second fixed position in the longitudinal direction, the system is capable of detecting curvature of the base member between the first fixed position and the second fixed position based on change in a relative position between the third linear member and the fourth linear member, the first linear member and the second linear member are disposed in one or more lumens provided in the base member, and the third linear member and the fourth linear member are disposed in other one or more lumens provided at a position different from a position of the one or more lumens for the first linear member and the second linear member in the circumferential direction of the wall.
  2. 2 . The curvature detection system according to claim 1 , wherein the first linear member and the second linear member are disposed in one or more lumens provided in the base member.
  3. 3 . The curvature detection system according to claim 2 , wherein the first linear member and the second linear member are disposed in separate lumens.
  4. 4 . The curvature detection system according to claim 1 , wherein the first linear member and the second linear member are disposed in one or more lumens provided in the base member, and the one or more lumens are formed in the wall.
  5. 5 . The curvature detection system according to claim 1 , wherein markers indicating a relative position between the first linear member and the second linear member are provided on the first linear member and the second linear member.
  6. 6 . The curvature detection system according to claim 1 , wherein markers indicating a relative position between the third linear member and the fourth linear member are provided on the third linear member and the fourth linear member.
  7. 7 . The curvature detection system according to claim 1 , comprising: a second sensor configured to detect change in a relative position between the third linear member and the fourth linear member.
  8. 8 . A balloon catheter system comprising: a balloon; a base member having a longitudinal direction, wherein the base member is a cylindrical member having a wall delimiting a hollow; a catheter shaft having an outer cylinder shaft connected to a proximal end of the balloon, an inner cylinder shaft having a longitudinal direction and extending into the balloon to be connected to a distal end of the balloon, a first linear member extending in the longitudinal direction, and a second linear member extending in the longitudinal direction, wherein the inner cylinder shaft extends inside the outer cylinder shaft, a gap between the inner cylinder shaft and the outer cylinder shaft serves as a liquid delivery path in communication with an inside space of the balloon, the first linear member is fixed to the base member at a first fixed position and is relatively movable with respect to the base member in the longitudinal direction, on one side of the first fixed position in the longitudinal direction, and the second linear member is fixed to the base member at a second fixed position different from the first fixed position and is relatively movable with respect to the base member in the longitudinal direction, on the one side of the second fixed position in the longitudinal direction; a heating member that heats a liquid in the balloon, the heating member being disposed on an outer circumferential surface of the inner cylinder shaft in the balloon; and a distance displacement sensor, wherein the sensor is configured to detect change in a relative position between the first linear member and the second linear member, thereby detecting curvature of the base member between the first fixed position and the second fixed position based on change in the relative position between the first linear member and the second linear member.
  9. 9 . A curvature detection system, comprising: a base member having a longitudinal direction; a first linear member extending in the longitudinal direction, wherein the first linear member is fixed to the base member at a first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on one side of the first fixed position in the longitudinal direction; a second linear member extending in the longitudinal direction, wherein the second linear member is fixed to the base member at a second fixed position different from the first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on the one side of the second fixed position in the longitudinal direction; and a distance displacement sensor, wherein the sensor is configured to detect change in a relative position between the first linear member and the second linear member, thereby detecting curvature of the base member between the first fixed position and the second fixed position based on change in the relative position between the first linear member and the second linear member, and comprises a first sensor at a second, unfixed, end of the first linear member and a second sensor at a second, unfixed end, of the second linear member.

Description

TECHNICAL FIELD This disclosure relates to a base member with a curvature detection function, a curvature detection system, a device comprising the base member with the curvature detection function, and a balloon catheter. BACKGROUND Catheter ablation therapy is a treatment method that uses a catheter inserted into a body to ablate a target site in the human body. As an example, a target site is destroyed by ablation to treat diseases such as arrhythmia due to atrial fibrillation, endometriosis, cancer and the like. As disclosed in JP 4062935 B2, JP 4226040 B2 and JP 4222152 B2, a balloon catheter having a distal end to which a balloon is attached is known as a catheter used for catheter ablation therapy. A balloon catheter has a catheter shaft inserted into a human body, and a balloon provided at a distant end of the catheter shaft. The catheter shaft is formed of a long flexible base member. The catheter shaft is inserted into a human body and is guided to a vicinity of a target site, and then a liquid is supplied into the balloon through an inside space of the catheter shaft so that the balloon is inflated. Since a temperature of the liquid in the balloon has been controlled, a surface temperature of the balloon can be controlled. By bringing the balloon whose surface temperature has been adjusted to a predetermined one into contact with a circumferential target site, e.g., a connection of a vein to an atrium, the circumferential target site can be ablated at once. When a distant end portion of the balloon catheter is curved, it may cause inconveniences such as loss of control of the balloon surface temperature. Thus, to be able to detect the curvature of a distant end portion of a balloon catheter is one of the needs for balloon catheters. Other devices including a long flexible base member (for example, catheter of another type, medical endoscope, industrial endoscope and the like) have a similar need. Although a distant end portion of a balloon catheter can be seen through a radioscopic image, the radioscopic image provides only two-dimensional information. Thus, it is often difficult to find out, from a radioscopic image, whether the distant end portion is curved, and/or in which direction the distant end portion is curved. JP 3917391 B2 discloses a medical endoscope that detects curvature of a long base member by using an optical fiber disposed in the base member. However, the base member is required to have a certain degree of thickness (external dimensions) to detect curvature by means an optical fiber disposed in the base member. Thus, it is difficult to apply the aforementioned curvature detection method to a device such as a balloon catheter on which severe restrictions on external dimensions of a base member (catheter shaft) are imposed. It could therefore be helpful to detect the curvature of a base member with increase in external dimensions of the base member minimized. SUMMARY I thus provide: A base member with a curvature detection function comprises: a base member having a longitudinal direction; a first linear member extending in the longitudinal direction; and a second linear member extending in the longitudinal direction. The first linear member is fixed to the base member at a first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on one side of the first fixed position in the longitudinal direction. The second linear member is fixed to the base member at a second fixed position different from the first fixed position, and is relatively movable with respect to the base member in the longitudinal direction, on the one side of the second fixed position in the longitudinal direction. The base member with the curvature detection function is capable of detecting curvature of the base member between the first fixed position and the second fixed position based on change in a relative position between the first linear member and the second linear member. In the base member with the curvature detection function, the first linear member and the second linear member may be disposed in one or more lumens provided in the base member. The first linear member and the second linear member may be disposed in separate lumens. The base member may be a cylindrical member having a wall delimiting a hollow. The first linear member and the second linear member may be disposed in one or more lumens provided in the base member, and the one or more lumens may be formed in the wall. Markers indicating a relative position between the first linear member and the second linear member may be provided on the first linear member and the second linear member. The base member with the curvature detection function may comprise a third linear member and a fourth linear member, the third and fourth linear members extending along the longitudinal direction at a position/positions different from a position/positions of the first linear member and the second linear mem