Catheter

Abstract

This catheter is provided with: a shaft that is inserted into a body; and a plurality of sets of splines 3 that are each configured from two splines that are connected to the distal end side of the shaft. The two splines 3 constituting a set of the splines 3 are arranged across at least one spline 3 belonging to another set. The plurality of sets of splines 3 are each constrained by a single restraining member in terms of movement between the same.

Description

catheter

[0001] The present disclosure relates to catheters.

[0002] A catheter is a type of medical device inserted into the body for diagnosis or treatment. For example, a catheter including a shaft and a basket electrode assembly coupled to the distal end of the shaft is known (see, for example, Patent Document 1). The basket electrode assembly includes a plurality of splines. The basket electrode assembly is configured to change shape from a contracted shape to an expanded shape by deforming the splines.

[0003] Special Publication No. 2016-507349

[0004] When the above-described catheter is deformed with the splines in contact with tissue inside the body, the spacing between the splines may become too narrow or too wide.

[0005] The present disclosure has been made in consideration of the above circumstances, and its object is to provide a catheter that can be deformed while maintaining splines at appropriate intervals.

[0006] One aspect of the present disclosure is a catheter. The catheter includes a shaft to be inserted into a body and multiple sets of splines, each consisting of two splines connected to the distal end of the shaft. The two splines constituting a set of splines are arranged with at least one spline belonging to another set sandwiched between them. The movements of the multiple sets of splines are constrained relative to each other by a single restraining member.

[0007] Another aspect of the present disclosure is a catheter. The catheter includes a shaft to be inserted into a body and a plurality of splines connected to a distal end of the shaft. The plurality of splines includes a first spline and a second spline. The first spline and the second spline are arranged with at least one other spline therebetween, and their mutual movement is constrained by a first restraining member.

[0008] Any combination of the above components, and conversion of the expression of the present disclosure into a method, device, system, etc., are also valid aspects of the present disclosure.

[0009] The catheter of the present disclosure can be deformed while maintaining the splines at the appropriate spacing.

[0010] 13 is a perspective view schematically showing an example of a deformed state near the tip of a catheter according to a first embodiment of the present disclosure. FIG. 14 is a perspective view schematically showing another example of a deformed state near the tip of a catheter according to a first embodiment of the present disclosure. FIG. 15 is a perspective view showing a spline removed from among the members constituting the catheter shown in FIG. 1. FIG. 16 is a perspective view showing a tip member removed from among the members constituting the catheter shown in FIG. 1. FIG. 17 is an enlarged view of the tip region shown in FIG. 4. FIG. 18 is a side view schematically showing an example of a structure near the tip of a catheter according to this embodiment. FIG. 19 is a cross-sectional view taken along line A-A shown in FIG. 6. FIG. 19 is a cross-sectional view taken along line B-B shown in FIG. 6. FIG. 19 is a schematic view showing an example of the overall structure of a catheter according to the present disclosure. FIG. 19 is a cross-sectional view taken along line C-C shown in FIG. 6. FIG. 19 is a perspective view schematically showing an example of a deformed state near the tip of a catheter according to a second embodiment. FIG. 19 is an enlarged view of the tip region shown in FIG. 11, showing a tip member removed from among the members constituting the catheter shown in FIG. 11. FIG. 19 is a schematic view from the tip side, showing a tip member removed from among the members constituting the catheter shown in FIG. 11. FIG. 19 is a perspective view schematically showing an example of a deformed state near the tip of a catheter according to a third embodiment. FIG. 19 is an enlarged view of a connecting portion of a plurality of restraining members shown in FIG. 14. 15 is a diagram showing an example in which the connecting portions of the restraining members shown in FIG. 14 are not exposed from the tip end side of the spline. FIG.

[0011] The present disclosure will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are intended to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0012] [First Embodiment] FIG. 1 is a perspective view schematically illustrating an example of a deformed state near the distal end of a catheter 1 according to a first embodiment of the present disclosure. FIG. 2 is a perspective view schematically illustrating another example of a deformed state near the distal end of a catheter 1 according to a first embodiment of the present disclosure. As shown in FIGS. 1 and 2 , the catheter 1 includes a shaft 2 to be inserted into a body, a plurality of splines 3a to 3h connected to the distal end of the shaft 2, and a distal end member 4 connected to the distal end of each of the plurality of splines 3a to 3h. Hereinafter, descriptions common to each of the plurality of splines 3a to 3h will be simply referred to as spline 3. Regarding other reference numerals with an alphabetical character at the end, descriptions common to those reference numerals will be written without the alphabetical character as appropriate. Hereinafter, the side of the catheter 1 inserted into the body will be referred to as the "distal side," and the side disposed outside the body will be referred to as the "proximal side." Furthermore, for each component constituting the catheter 1, the side that is the same as the distal side of the catheter 1 will be referred to as the "distal side" of that component, and the side that is the same as the proximal side of the catheter 1 will be referred to as the "proximal side" of that component.

[0013] The shaft 2 may be a long, cylindrical member. The length of the shaft 2 is, for example, 800 mm to 1800 mm. The outer diameter of the shaft 2 is, for example, 2.0 mm to 5.0 mm. The material forming the shaft 2 may be any material that is flexible and biocompatible. For example, the shaft 2 may be formed from a known resin such as polyolefin or polyamide.

[0014] The spline 3 is a member that connects the shaft 2 and the tip member 4. The spline 3 may be a cylindrical member, similar to the shaft 2. The length of the spline 3 when extended linearly is, for example, 20 mm to 50 mm. The outer diameter of the spline 3 is, for example, 0.5 mm to 2.0 mm. The material that constitutes the spline 3 may be any material that is flexible and biocompatible. For example, the spline 3, like the shaft 2, may be made of a known resin such as polyolefin or polyamide.

[0015] The catheter 1 according to this embodiment includes eight splines 3a to 3h. The splines 3a to 3h are arranged adjacent to each other in the following order in a clockwise direction along the circumferential direction when viewed from the distal end. That is, spline 3a and spline 3b, spline 3b and spline 3c, spline 3c and spline 3d, spline 3d and spline 3e, spline 3e and spline 3f, spline 3f and spline 3g, spline 3g and spline 3h, and spline 3h and spline 3a are adjacent to each other. Furthermore, the splines 3 are arranged spaced apart from each other in a plane perpendicular to the central axis of the shaft 2.

[0016] The spline 3 is connected to the shaft 2. As an example, a portion of the spline 3 including the base end (base end portion) is inserted into the tip side of the shaft 2. The base end portion of the spline 3 and the shaft 2 are joined to each other by a known joining method such as welding or bonding with an adhesive.

[0017] The splines 3 are configured to change, i.e., deform, in response to a deformation operation, which will be described later. Specifically, the shape of each spline 3 changes between a non-deployed or contracted shape in which the splines 3 are not deployed along the central axis of the shaft 2, and a deployed or expanded shape in which the splines 3 are deployed from the non-deployed shape along the central axis of the shaft 2. As will be described in detail later, an example of the non-deployed shape is a "petal shape" (see FIG. 2). On the other hand, an example of the deployed shape is a "basket shape" (see FIG. 1) in which the splines 3 are deployed from the petal shape along the central axis of the shaft 2.

[0018] FIG. 3 is a perspective view of the catheter 1 shown in FIG. 1 , with the spline 3 removed. FIG. 4 is a perspective view of the catheter 1 shown in FIG. 1 , with the tip member 4 removed. FIG. 5 is an enlarged view of the tip region S shown in FIG. 4 . As shown in FIGS. 3 to 5 , the splines 3a and 3c are constrained from moving relative to each other by a restraining member 6a. Here, "their movements are constrained" means that when the splines 3a and 3c are deformed, they maintain an appropriate distance between them. Note that "space" here refers to the shortest distance between the distal end of the spline 3a and the distal end of the spline 3c. Therefore, even if a deformation operation is performed while the spline 3a is in contact with tissue inside the body, the splines 3a and 3c deform while maintaining an appropriate distance between them via the restraining member 6a. Because of this configuration, the catheter 1 of this embodiment can maintain the splines 3 at an appropriate distance and deform into a desired shape, i.e., a non-deployed shape or a deployed shape.

[0019] Spline 3a and spline 3c, whose mutual movement is constrained by constraining member 6a, are disposed on either side of spline 3b and are not adjacent to each other. Therefore, compared to constraining the movement of adjacent splines 3, the movement of distant splines 3 is constrained, making machining easier. The greater the number of splines 3 included in catheter 1, the more precise machining is required, and therefore the above-mentioned effect of this configuration becomes more pronounced.

[0020] The above-described configuration can also be expressed as follows: In other words, when the spline 3a is the first spline, the spline 3c is the second spline, and the restraining member 6a is the first restraining member, the first spline and the second spline are disposed with at least one other spline therebetween, and the movements of the first spline and the second spline are restrained by the first restraining member.

[0021] As described above, spline 3a and spline 3c constitute a pair of splines 3 whose mutual movement is constrained by a single restraining member 6a. Similarly, spline 3b and spline 3d constitute another pair of splines 3 whose mutual movement is constrained by a single restraining member 6b. Furthermore, spline 3a and spline 3c constituting a pair of splines 3 are arranged with one spline 3b belonging to another pair sandwiched between them. As a result, similar to the above, the catheter 1 of this embodiment can maintain the splines 3 at an appropriate interval, can be deformed into a desired shape, and can be more easily processed.

[0022] The above-described configurations for the pair of splines 3a and 3c and the pair of splines 3b and 3d may be similarly applied to the other splines 3. In other words, the splines 3 arranged with at least one spline sandwiched between them may each have their movement constrained by a single restraining member 6. Specifically, the splines 3c and 3e may have their movement constrained by a restraining member 6c. The splines 3d and 3f may have their movement constrained by a restraining member 6d. The splines 3e and 3g may have their movement constrained by a restraining member 6e. The splines 3f and 3h may have their movement constrained by a restraining member 6f. The splines 3g and 3a may have their movement constrained by a restraining member 6g. The splines 3h and 3b may have their movement constrained by a restraining member 6h. In other words, the catheter 1 includes multiple pairs of splines 3 each having their movement constrained by a single restraining member 6. Here, one set of splines 3 is made up of two splines 3. As described above, one spline 3 forms a different set with the other two splines 3. For example, spline 3a forms a set with spline 3c, and also forms a set with spline 3g.

[0023] In the present embodiment, an example has been shown in which a set of splines 3 is disposed with one spline 3 sandwiched between them. However, it is sufficient that a set of splines 3 is disposed with at least one other spline 3 sandwiched between them. In other words, a set of splines 3 may be disposed with two splines 3 sandwiched between them, or may be disposed with three or more splines 3 sandwiched between them.

[0024] The restraining member 6 may have any shape, structure, or material as long as it is a member that can restrain the mutual movement of the two splines 3 that make up one set of splines 3. As an example, the restraining member 6 is a wire. The material of the wire may be a shape memory alloy such as a nickel-titanium alloy.

[0025] The restraining member 6 may have a first end and a second end. Furthermore, at least a portion of the first end of the restraining member 6 may be located within one of the splines 3 constituting the set of splines 3, and at least a portion of the second end of the restraining member 6 may be located within the other of the splines 3 constituting the set of splines 3. The restraining member 6 may have a connecting portion that connects the tip of one of the splines 3 to the tip of the other of the splines 3. In this embodiment, the connecting portion is a protrusion 15 that protrudes distally beyond the tip of one of the splines 3 and the tip of the other of the splines 3. Here, "at least a portion of the first end" refers to a portion of the restraining member 6 that has a constant length continuing from the first end of the protrusion 15. Furthermore, "at least a portion of the second end" refers to a portion of the restraining member 6 that has a constant length continuing from the second end of the protrusion 15. In this way, when the restraint member 6 is configured to connect the tips of a pair of splines 3 together by a connecting portion, the catheter 1 of this embodiment connects the tips of non-adjacent splines 3 that are farther apart than connecting the tips of adjacent splines 3, making processing easier.

[0026] For example, at least a portion of the first end of the restraining member 6 a may be located within the spline 3 a, and at least a portion of the second end of the restraining member 6 a may be located within the spline 3 c. The restraining member 6 a may have a protruding portion 15 a that protrudes distally beyond the tip of the spline 3 a and the tip of the spline 3 c.

[0027] The first end of the restraining member 6 may be located closer to the base end than the base end of one of the splines 3. The second end of the restraining member 6 may be located closer to the base end than the base end of the other spline 3. For example, the first end of the restraining member 6a may be located closer to the base end than the base end of the spline 3a. Also, for example, the second end of the restraining member 6a may be located closer to the base end than the base end of the spline 3c. If such a configuration is satisfied, the restraining member 6 serves as a framework that maintains the shape of the two splines 3 that make up the set of splines 3.

[0028] When the restraining member 6 is a wire, the protrusion 15 may have a U-shaped bend. When at least one of a pair of splines 3 restrained by the restraining member 6 is deformed, the restraining member 6 also deforms in conjunction with the deformation. At this time, stress generated by the deformation is concentrated on the protrusion 15. If the protrusion 15 has a U-shaped bend, the above-mentioned stress can be effectively alleviated, and the risk of the protrusion 15 breaking even when repeatedly deforming is reduced.

[0029] Fig. 6 is a side view schematically illustrating an example of the structure near the distal end of the catheter 1 of this embodiment. Fig. 7 is a cross-sectional view taken along line A-A in Fig. 6. As shown in Fig. 7, the spline 3a may have a multi-lumen structure. Specifically, the spline 3a has four lumens 7 (7a1, 7b1, 7c1, 7d1) extending from the distal end to the proximal end along the central axis of the spline 3a. Here, the lumens 7a1 and 7b1 are located closer to the central axis of the shaft 2 than the lumens 7c1 and 7d1. Furthermore, the lumens 7b1 and 7c1 are located closer to the spline 3b than the lumens 7a1 and 7d1.

[0030] Like the spline 3a, the spline 3c may have a multi-lumen structure. Specifically, the spline 3c has four lumens 7 (7a3, 7b3, 7c3, 7d3) extending from the distal end to the proximal end along the central axis of the spline 3c. The lumens 7a3 and 7b3 are located closer to the central axis of the shaft 2 than the lumens 7c3 and 7d3. The lumens 7a3 and 7d3 are also located closer to the spline 3b than the lumens 7b3 and 7c3.

[0031] The first end of the restraining member 6a may be inserted into the lumen 7c1 of the spline 3a, while the second end of the restraining member 6a may be inserted into the lumen 7d3 of the spline 3c. By inserting the restraining member 6a into the lumen 7c1, 7d3 of the lumens 7 of the spline 3a and the spline 3c that is located farther from the central axis of the shaft 2 and closest to the spline 3a, the spline 3c is maintained at a more appropriate distance.

[0032] In the above-described embodiment, the splines 3a, 3c, and the restraining member 6a have been described as examples, but the same may be true for the other splines 3 and restraining members 6. In this case, the splines 3 in each set are positioned away from the central axis of the shaft 2, and the restraining member 6 is inserted into the set of lumens 7 that are closest to each other, so that the restraining members 6 are unlikely to interfere with each other.

[0033] As shown in Fig. 6, each spline 3 may have one or more electrodes 5. The electrodes 5 are ring-shaped electrodes for measuring electric potential or for cauterization. The electrodes 5 of the same spline 3 are arranged at a distance from each other along the longitudinal direction of the spline 3. In this case, the distance between adjacent electrodes 5 may be constant or may vary. Furthermore, the number of electrodes 5 of each spline 3 may be the same or may vary.

[0034] The electrode 5 is made of a conductive material. For example, the electrode 5 is made of a metal with good electrical conductivity, such as aluminum (Al), copper (Cu), stainless steel, gold (Au), or platinum (Pt). The length of the electrode 5 is, for example, 0.5 mm to 2.0 mm. The outer diameter of the electrode 5 may be equal to the outer diameter of the spline 3, and is, for example, 0.5 mm to 1.6 mm.

[0035] Conductive wires are individually and electrically connected to the electrodes 5. The conductive wires pass from inside the spline 3 through the shaft 2 and the handle 8 (described later) and are connected to an external power supply device via the handle 8. As an example, the conductive wires connected to the electrodes 5 of the spline 3a pass through the lumen 7a1 or 7b1 of the spline 3a while being electrically insulated from each other. The same applies to the splines 3 other than the spline 3a.

[0036] As shown in FIGS. 2 and 4 , the tip member 4 may cover a portion of the spline 3 a including the tip thereof (hereinafter referred to as the “tip portion”), the tip portion of the spline 3 c, and the protrusion 15 a of the restraining member 6 a. In other words, the tip member 4 may cover the tip portions of the spline 3 a, the tip portions of the spline 3 c, and the protrusion 15 of the restraining member 6 a. The tip member 4 may have any shape, and is cap-shaped as an example. The tip member 4 may be made of any material, and is made of known resins such as nylon, nylon elastomer, polycarbonate, etc., or known metals such as stainless steel, etc. Note that the tip member 4 may entirely cover the tip portions of each spline 3 and the protrusion 15 of each restraining member 6.

[0037] 8 is a cross-sectional view taken along line B-B in FIG. 6. As shown in FIG. 8, in a plan view seen from the base end side of the distal end member 4, the wall portion constituting the inner surface of the distal end member 4 may have adjacent recesses 9a and 9b. At least a portion of the tip end of the spline 3a may be located in the recess 9a, and at least a portion of the tip end of the spline 3b may be located in the recess 9b. Here, "at least a portion of the tip end of the spline 3 being located in the recess 9" means that, in a plan view seen from the base end side of the distal end member 4, the spline 3 has a portion that overlaps with the region of the recess 9. If this configuration is satisfied, the recesses 9a and 9b can prevent the tip end of the spline 3a and the tip end of the spline 3b from becoming misaligned when the spline 3a and the spline 3b are deformed.

[0038] As an example, the shapes of the recesses 9a and 9b are semicircular in a plan view seen from the base end side of the tip member 4. Furthermore, the wall portion constituting the recess 9a may or may not be in contact with the spline 3a. Similarly, the wall portion constituting the recess 9b may or may not be in contact with the spline 3b. Note that Figure 8 illustrates an example in which the wall portion constituting the inner surface of the tip member 4 has eight recesses 9. In this way, the wall portion constituting the inner surface of the tip member 4 may have recesses 9 corresponding to each spline 3.

[0039] The inside of the tip member 4 may be filled with adhesive. If such a configuration is satisfied, the splines 3a, 3c, and the restraining member 6a are firmly joined by the adhesive, so that the splines 3a and 3c are maintained at a more appropriate distance. This also applies to the splines 3 other than the splines 3a and 3c, and the restraining members 6 other than the restraining member 6a.

[0040] As shown in Fig. 5, the tip member 4 may include a bundling member 10 therein that bundles the protrusions 15a of the restraining members 6a. Here, bundling the protrusions 15a means restraining the protrusions 15a so that they do not move in a plane perpendicular to the central axis of the shaft 2. If this configuration is satisfied, the bundling member 10 suppresses twisting of the restraining members 6a, making it easier to effectively link the deformation of the splines 3a and 3c via the restraining members 6a. Note that the bundling member 10 may bundle the protrusions 15 of all of the restraining members 6.

[0041] The binding member 10 may have any shape, structure, or material as long as it can bind the protrusions 15a. For example, the binding member 10 is plate-like, having a top surface at the distal end (hereinafter referred to as the "first surface") and a bottom surface at the proximal end (hereinafter referred to as the "second surface") that is the reverse side of the first surface. The second surface faces the distal end surfaces of the splines 3a and 3c. The binding member 10 also has a through-hole 16a that penetrates from the first surface to the second surface, into which the protrusions 15a of the restraining member 6a are inserted. The side surface connecting the first and second surfaces of the binding member 10 (hereinafter referred to as the "third surface") may have any shape corresponding to the wall portion that constitutes the inner surface of the distal end member 4. Specifically, the binding member 10 may have any shape that includes protrusions that correspond to the recesses 9 of the distal end member 4. The binding member 10 may be made of any material that has high rigidity. For example, the binding member 10 may be made of a known metal such as stainless steel. The binding member 10 may be provided with through holes 16 that correspond to the protrusions 15 of the restraining members 6, respectively.

[0042] The through-hole 16a may have any shape as long as the protrusion 15a of the restraining member 6a can be inserted therein. As an example, the shape of the through-hole 16a is elliptical in a plan view seen from the first surface side of the binding member 10. The other through-holes 16 may have a similar shape.

[0043] As shown in Figure 5, the restraining members 6a corresponding to the splines 3a and 3c and the restraining members 6b corresponding to the splines 3b and 3d may have their respective protrusions 15a and 15b bent in different directions when viewed from the distal end. Here, "when viewed from the distal end" means viewing the catheter 1 from the distal end side of the catheter 1. The restraining members 6a and 6b partially overlap in the circumferential direction of the catheter 1. In this embodiment, the restraining member 6a is bent more radially outward than the restraining member 6b. The same may be true for the restraining members 6 other than the restraining members 6a and 6b that partially overlap in the circumferential direction of the catheter 1.

[0044] In this way, the protrusions 15 of the first restraining member 6 corresponding to the first set of splines 3 and the second restraining member 6 corresponding to the second set of splines 3, which includes a spline 3 sandwiched between two splines 3 constituting the first set of splines 3, may be bent in different directions when viewed from the tip side. This makes it less likely for the restraining members 6 to interfere with each other, making processing easier. Such restraining members 6 can be made, for example, of shape memory alloy wires bent into different shapes.

[0045] Fig. 9 is a schematic diagram showing an example of the overall structure of the catheter 1 of the present disclosure. As shown in Fig. 10, the catheter 1 may include a handle 8 connected to the proximal end of the shaft 2. The handle 8 is a part that an operator such as a doctor grasps or holds when using the catheter 1. The handle 8 may include a handle main body 11 attached to the proximal end of the shaft 2, a rotation operation unit 12, and a slide member 13.

[0046] The handle body 11 corresponds to the part that the operator actually grips. The handle body 11 may have any shape. For example, the handle body 11 has a shape that extends along the central axis of the shaft 2. The handle body 11 is made of a known resin such as polycarbonate, polyacetal, ABS, etc.

[0047] The rotation operation unit 12 is a part that is operated by a rotation operation or the like when bidirectionally bending or flexing the vicinity of the tip of the shaft 2. The base ends of a pair of pull wires are fixed to the rotation operation unit 12 within the handle main body 11. The tips of the pair of pull wires pass from the handle main body 11 through the shaft 2 and are fixed to the tip side of the shaft 2. Therefore, when the rotation operation unit 12 is operated, the pull wires are pulled toward the base end, and the tip side of the shaft 2 to which the tips of the pull wires are fixed is bent or flexed.

[0048] The slide member 13 is a part that is slid by an operator when the shape of the spline 3 is changed between the undeployed or contracted shape and the expanded or expanded shape. The slide member 13 is slidable along the central axis of the shaft 2 in the handle body 11.

[0049] The base end of the deformation member 14 is fixed to the slide member 13. The tip of the deformation member 14 passes from inside the handle main body 11 through the shaft 2 and is fixed in the tip member 4. The slide member 13 is movable to any position along the central axis of the shaft 2 in the handle main body 11. Therefore, depending on the position of the slide member 13, the shape of the spline 3 can be deformed to the undeployed shape or contracted shape, the deployed shape or expanded shape, or any intermediate shape between the undeployed shape and the deployed shape.

[0050] The deformation member 14 may have any shape, structure, or material as long as it is long. As an example, the deformation member 14 is a wire that is thicker than the restraint member 6.

[0051] Figure 10 is a cross-sectional view taken along line CC shown in Figure 6. As shown in Figure 10, the shaft 2 has a large lumen 18 at a position including the center of the radially inner side. The large lumen 18 extends from the proximal end to the distal end of the shaft 2. The shaft 2 has eight small lumens 17a to 17h arranged circumferentially around the large lumen 18, and two pullwire lumens 19a, 19b arranged symmetrically about the approximate center of the shaft 2. The eight small lumens 17a to 17h are arranged adjacent to each other in the stated order clockwise along the circumferential direction when viewed from the distal end.

[0052] The first and second ends of each of the multiple restraining members 6 may be disposed within the shaft 2. Specifically, the first end of restraining member 6a is disposed within small lumen 17a, and the second end of restraining member 6a is disposed within small lumen 17c. Similarly, the first end of restraining member 6b is disposed within small lumen 17b, and the second end of restraining member 6b is disposed within small lumen 17d. The same may be true for the other restraining members 6.

[0053] A pair of pull wires 22a, 22b extend from the proximal end to the distal end within shaft 2. Specifically, pull wire 22a is disposed within pull wire lumen 19a. Pull wire 22b is disposed within pull wire lumen 19b. As a result, the pair of pull wires 22a, 22b are disposed symmetrically with respect to approximately the center of shaft 2 in a cross-sectional view perpendicular to the axis of shaft 2 shown in FIG. 10 .

[0054] 10 , the eight small lumens 17a to 17h are arranged symmetrically with respect to a line 24 that passes through the center positions of the pair of pull wires 22a and 22b. Specifically, small lumens 17a and 17f, small lumens 17b and 17e, small lumens 17c and 17d, and small lumens 17g and 17h are each arranged symmetrically with respect to the line 24. Therefore, the multiple restraining members 6 arranged in the multiple small lumens 17 are also arranged symmetrically with respect to the line 24. As a result, when attempting to bend the vicinity of the tip of the shaft 2 in two directions on the same plane using the pair of pull wires 22a and 22b, imbalances in flexibility and weight balance on both sides of the plane are reduced, thereby improving planarity.

[0055] Although the term "axis symmetry" is used for convenience in this embodiment, it is not required that the small lumens 17 be arranged in strict axis symmetry in the actual shaft 2. For example, it is sufficient that the small lumens 17 are arranged within a predetermined distance from the axis symmetric position. Specifically, it is sufficient that the distance from the axis symmetric position of each small lumen 17 is within 30% of the diameter of the lumen 17, preferably within 20%, and more preferably within 10%.

[0056] 10, the eight small lumens 17a to 17h are arranged point-symmetrically with respect to the axis of the shaft 2. Specifically, small lumens 17a and 17e, small lumens 17b and 17f, small lumens 17c and 17g, and small lumens 17d and 17h are each arranged point-symmetrically with respect to the axis of the shaft 2. Therefore, the multiple restraining members 6 arranged in the multiple small lumens 17 are also arranged point-symmetrically with respect to the axis of the shaft 2. This reduces imbalances in flexibility and weight balance at positions facing the axis of the shaft 2, thereby further improving planarity.

[0057] Although the term "point symmetry" is used in this embodiment for convenience, it is not required that the small lumens 17 be provided in strict point symmetry in the actual shaft 2. For example, it is sufficient that the small lumens 17 are disposed within a predetermined distance from the point symmetric position. Specifically, it is sufficient that the distance from the point symmetric position of each small lumen 17 is within 30% of the diameter of the lumen 17, preferably within 20%, and more preferably within 10%.

[0058] Furthermore, as described above, by arranging multiple restraining members 6 inside the small lumen 17 that is arranged around the large lumen 18 of the shaft 2, it is possible to ensure a wide cross-sectional area perpendicular to the axial direction of the large lumen 18. This makes it easier to arrange multiple conducting wires 26, the water supply tube 28, the deformation member 14 that is arranged at a position including the center of the water supply tube 28, and other components that are arranged inside the large lumen 18, as shown in Figure 10.

[0059] As described above, the catheter 1 according to the first embodiment has been described as including eight splines 3a to 3h. However, the number of splines 3 included in the catheter 1 is not limited to eight, and may be four or more. However, as described above, from the viewpoint of achieving a balanced operation using the pair of pull wires 22, it is preferable that the number of splines 3 is an even number.

[0060] [Second embodiment] A second embodiment of the present disclosure will be described with reference to Figures 11 to 13. In the following embodiments, the same content as in the first embodiment may be applied to components described in the first embodiment but not described below. Figure 11 is a perspective view schematically showing an example of a deformation state near the tip of a catheter 101 according to the second embodiment.

[0061] The catheter 101 includes a shaft 102 to be inserted into the body, a plurality of splines 103a to 103l connected to the distal end of the shaft 102, and a distal end member 104 connected to the distal end of each of the splines 103a to 103l. The splines 103a to 103l are arranged adjacent to each other in this order in a clockwise direction along the circumferential direction as viewed from the distal end. The catheter 101 of this embodiment differs from the catheter 1 of the first embodiment in that it includes twelve splines 103a to 103l. The configuration of each spline 103 is similar to the spline 3 of the first embodiment. The shaft 102 and the distal end member 104 are similar to the shaft 2 and the distal end member 4 of the first embodiment, respectively, except that they have shapes corresponding to the twelve splines 103a to 103l. Similar to FIG. 1 of the first embodiment, FIG. 11 shows the spline 103 in an expanded "basket shape."

[0062] Fig. 12 is an enlarged view of the distal end region T shown in Fig. 11 , with the distal end member 104 removed from among the components constituting the catheter 101 shown in Fig. 11 . Fig. 13 is a schematic view seen from the distal end side, with the distal end member 104 removed from among the components constituting the catheter 101 shown in Fig. 11 . As shown in Figs. 12 and 13 , the restraining member 106a restrains the splines 103a and 103d. The restraining member 106b restrains the splines 103b and 103e. The restraining member 106c restrains the splines 103c and 103f. Thus, in this embodiment, one set of splines 103a and 103d are arranged with two splines 103b and 103c belonging to the other set sandwiched between them. This also applies to the other splines 103.

[0063] As shown in FIG. 13 , the protruding portions of the restraining member 106a corresponding to the splines 103a and 103d, the restraining member 106b corresponding to the splines 103b and 103e, and the restraining member 106c corresponding to the splines 103c and 103f may be bent in different directions when viewed from the distal end. The restraining members 106a, 106b, and 106c partially overlap in the circumferential direction of the catheter 101. In this embodiment, the restraining member 106a is bent more radially inward of the catheter 101 than the restraining members 106b and 106c. The restraining member 106b is bent less than the restraining members 106a and 106c. The restraining member 106c is bent more radially outward of the catheter 101 than the restraining members 106a and 106b. The same may be true for the restraining members 106 other than the restraining members 106a, 106b, and 106c that partially overlap in the circumferential direction of the catheter 101. As a result, the catheter 101 of this embodiment can also achieve the same effects as the first embodiment.

[0064] Third Embodiment A third embodiment of the present disclosure will be described with reference to Figures 14 to 16. Figure 14 is a perspective view schematically illustrating an example of a deformed state near the tip of a catheter 201 according to the third embodiment. The catheter 201 includes a shaft 2 and a plurality of splines 3a to 3j connected to the tip side of the shaft 2. Although not shown in Figure 14, the catheter 201 may include a tip member, similar to the catheter 1 of the first embodiment.

[0065] The catheter 201 of this embodiment differs from the catheter 1 of the first embodiment in that the connecting portions of the restraining members 206 do not protrude toward the distal end. FIG. 15 is an enlarged view of the connecting portions of the multiple restraining members 206. As shown in FIG. 15, each restraining member 206 has a structure in which adjacent restraining members 206 in the circumferential direction are intertwined with each other. Specifically, in the example shown in FIG. 15, when the clockwise direction in the circumferential direction as viewed from the distal end is defined as the positive direction, the connecting portion of each restraining member 206 is positioned more distally than the connecting portion of the adjacent restraining member 206 in the negative direction and more proximal than the connecting portion of the adjacent restraining member 206 in the positive direction. By thus configuring the connecting portions of the individual restraining members 206 to be intertwined, the relative positions of the multiple restraining members 206 can be stabilized without using a member such as the binding member 10 of the first embodiment.

[0066] 16 is a diagram showing an example in which the connecting portion of each restraining member 206 is not exposed from the tip end side of the spline 3. Even with this configuration, each restraining member 206 can obtain the same effect as above.

[0067] The embodiments of the present disclosure have been described in detail above. The above-described embodiments merely illustrate specific examples of implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design modifications, such as changing, adding, or deleting components, are possible within the scope of the concept of the present disclosure defined in the claims. A new embodiment with design modifications will combine the effects of the combined embodiments and modifications. In the above-described embodiments, content that allows such design modifications is emphasized by using notations such as "in this embodiment" or "in this embodiment," but design modifications are also permitted even in content without such notation. Any combination of components included in each embodiment is also valid as an aspect of the present disclosure. Hatching on cross sections in the drawings does not limit the material of the hatched object.

[0068] Embodiments may be specified by the following items: [Item 1] A catheter (1) comprising: a shaft (2) to be inserted into a body; and multiple sets of splines (3) connected to the distal end of the shaft (2), wherein two splines (3) constituting one set of splines (3) are arranged with at least one spline (3) belonging to another set sandwiched between them, and wherein the movements of the multiple sets of splines (3) are constrained relative to each other by one restraining member (6). [Item 2] The restraining member (6) has a first end and a second end, wherein at least a portion of the first end side of the restraining member (6) is located within one of the splines (3) constituting the set of splines (3), and at least a portion of the second end side of the restraining member (6) is located within the other spline (3) constituting the set of splines (3), and the restraining member (6) has a connecting portion connecting the distal end of one spline (3) to the distal end of the other spline (3). [Item 3] The catheter (1) according to Item 2, wherein the connecting portion of the restraining member (6) is a protrusion (15) that protrudes distally beyond the tip of one spline (3) and the tip of the other spline (3). [Item 4] The catheter (1) according to Item 3, wherein the protrusions (15) of the first restraining member (6) corresponding to the first set of splines (3) and the second restraining member (6) corresponding to the second set of splines (3), which includes a spline (3) sandwiched between two splines (3) that make up the first set of splines (3), are bent in different directions when viewed from the distal end. [Item 5] The catheter (1) according to any of Items 2 to 4, wherein the first and second ends of each of the multiple restraining members (6) are disposed within the shaft (2), and the multiple restraining members (6) are arranged symmetrically with respect to a line (24) that passes through the centers of each of the pair of pull wires (22) in a cross-sectional view perpendicular to the axis of the shaft (2). [Item 6] The catheter (1) according to any one of Items 2 to 4, wherein the first and second ends of each of the plurality of restraining members (6) are disposed within the shaft (2), and the plurality of restraining members (6) are disposed point-symmetrically with respect to the axis of the shaft (2) in a cross-sectional view perpendicular to the axis of the shaft (2).[Item 7] The catheter (1) according to item 3 or 4, further comprising a tip member (4) covering the tip ends of the multiple sets of splines (3) and the protrusions (15) of the multiple restraining members (6). [Item 8] The catheter (1) according to item 7, wherein the tip member (4) has a bundling member (10) therein that bundles the protrusions (15) of the multiple restraining members (6). [Item 9] The catheter (1) according to item 8, wherein the bundling member (10) is shaped like a plate having a first surface and a second surface that is the reverse of the first surface, the second surface facing the tip ends of the multiple sets of splines (3), and the bundling member (10) is provided with through holes (16) that penetrate from the first surface to the second surface, and into which the protrusions (15) of the multiple restraining members (6) are inserted. [Item 10] The catheter (1) according to any of items 1 to 9, wherein the multiple restraining members are wires. [Item 11] A catheter (1) comprising: a shaft (2) to be inserted into a body; and a plurality of splines (3) connected to the distal end side of the shaft (2), wherein the plurality of splines (3) include a first spline (3) and a second spline (3), and the first spline (3) and the second spline (3) are arranged with at least one other spline (3) sandwiched therebetween, and the movements of the first spline (3) and the second spline (3) are constrained by a first restraining member (6).

[0069] The present disclosure can be utilized in catheters.

[0070] REFERENCE SIGNS LIST 1 catheter, 2 shaft, 3 spline, 4 tip member, 6 restraining member, 10 binding member, 15 protrusion, 16 through hole, 22 pull wire.

Claims

1. A catheter comprising: a shaft to be inserted into the body; and multiple sets of splines, each consisting of two splines connected to the tip side of the shaft, wherein the two splines constituting a set of splines are arranged with at least one spline belonging to another set sandwiched between them, and the movements of the multiple sets of splines are constrained relative to each other by a single restraining member.

2. The catheter of claim 1, wherein the restraining member has a first end and a second end, at least a portion of the first end side of the restraining member is located within one of the splines constituting the spline set, and at least a portion of the second end side of the restraining member is located within the other spline constituting the spline set, and the restraining member has a connecting portion connecting a tip of the one spline to a tip of the other spline.

3. The catheter according to claim 2, wherein the connecting portion of the restraining member is a protruding portion that protrudes distally beyond the tip of the one spline and the tip of the other spline.

4. A catheter as described in claim 3, wherein a first restraint member corresponding to a first set of splines and a second restraint member corresponding to a second set of splines including a spline sandwiched between two splines constituting the first set of splines have their respective protrusions bent in different directions when viewed from the tip side.

5. A catheter as described in any one of claims 2 to 4, wherein the first end and the second end of each of the multiple restraining members are disposed within the shaft, and in a cross-sectional view perpendicular to the axis of the shaft, the multiple restraining members are disposed symmetrically with respect to a line passing through the center positions of each of a pair of pull wires.

6. A catheter as described in any one of claims 2 to 4, wherein the first end and the second end of each of the multiple restraining members are disposed within the shaft, and in a cross-sectional view perpendicular to the axis of the shaft, the multiple restraining members are disposed point-symmetrically with respect to the axis of the shaft.

7. The catheter according to claim 3 or 4, further comprising a tip member covering the tip end of each of the plurality of sets of splines and the protrusions of each of the plurality of restraining members.

8. The catheter according to claim 7, wherein the tip member includes a bundling member therein for bundling the protrusions of each of the plurality of restraining members.

9. The catheter described in claim 8, wherein the binding member is shaped like a plate having a first surface and a second surface that is the reverse side of the first surface, the second surface facing the tip surface of each of the plurality of sets of splines, and the binding member is provided with through holes that extend from the first surface to the second surface, and into which the protrusions of each of the plurality of restraining members are inserted.

10. The catheter of claim 1, wherein the plurality of restraining members are wires.

11. A catheter comprising: a shaft to be inserted into a body; and a plurality of splines connected to a distal end of the shaft, the plurality of splines including a first spline and a second spline, the first spline and the second spline being disposed with at least one other spline therebetween, and the mutual movement of the first spline and the second spline being restrained by a first restraining member.

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