JP6438497B2 - Medical stimulation electrode - Google Patents

Description

  The present invention relates to a medical electrical stimulation electrode.

2. Description of the Related Art Conventionally, medical electrical stimulation electrodes that give electrical stimulation to biological tissues such as nerve tissue and muscle are known. The medical electrical stimulation electrode includes a stimulation electrode part and an elastic member that presses the stimulation electrode part against the inner wall of the blood vessel. The elastic member is folded when an external force is applied, and is inserted into the blood vessel together with the stimulation electrode portion in the folded state. When the external force for folding the elastic member in the blood vessel is released, the elastic member expands. As a result, the stimulation electrode portion is pressed against the inner wall of the blood vessel. The elastic member is locked to the blood vessel.
For example, U.S. Patent No. 6,057,836 discloses a conductive lead body having a proximal end configured to connect to a pulse generator and at least one electrode configured to deliver an electrical pulse across a vessel wall (stimulation electrode). A nerve stimulation lead including a distal end portion including a portion and a lead anchor (elastic member).
The lead anchor in the nerve stimulation lead is configured to expand from a folded shape to an expanded shape formed in advance. The distal end portion of the nerve stimulation lead is coupled to the outside of the lead anchor. When the lead anchor is expanded in the blood vessel, the lead anchor presses the tip of the nerve stimulation lead against the blood vessel wall. As a result, the position of the tip of the nerve stimulation lead in the blood vessel is fixed.

Japanese National Table 2010-516405

In order to appropriately perform electrical stimulation, the stimulation electrode unit needs to be accurately positioned at a stimulation site that appropriately stimulates a stimulation target such as a nerve.
When the nerve stimulation lead described in Patent Document 1 is disposed on the inner wall of a blood vessel, it can be disposed at the stimulation site by rotating within the blood vessel. However, when the position of the distal end portion of the nerve stimulation lead is shifted in the axial direction of the blood vessel with respect to the stimulation site, it is necessary to move the distal end portion also in the axial direction of the blood vessel.
In this case, Patent Document 1 describes that the distal end portion of the nerve stimulation lead is rearranged by reintroducing a guide member such as a guide catheter or a guide wire into the blood vessel and folding the lead anchor. .

However, when the lead anchor is folded again, a large force is applied to the lead anchor, which may cause plastic deformation of the lead anchor. When the lead anchor deformed plastically is expanded again, it does not return to the expanded shape before folding. For this reason, there exists a possibility that the pressing force which acts on a blood vessel from a lead anchor may fall. When the pressing force decreases, the position of the lead anchor in the blood vessel may not be stable.
Further, referring to FIG. 3 of Patent Document 1, the wire diameter of the lead anchor in Patent Document 1 is clearly smaller than the wire diameter of the distal end portion of the nerve stimulation lead. For this reason, the radial pressing force acting on the inner wall of the blood vessel from the distal end portion and the lead anchor of the nerve stimulation lead becomes uneven in the circumferential direction of the inner wall of the blood vessel. As a result, the reaction force acting on each part of the lead anchor from the inner wall of the blood vessel also varies. Accordingly, there is a concern that the portion of the lead anchor that receives an excessive reaction force changes with time during the indwelling period, and the pressing force on the blood vessel wall further decreases.

  The present invention has been made in view of the above problems, and an object thereof is to provide a medical electrical stimulation electrode that can be stably placed in a blood vessel even when folding is repeated.

The electrical stimulation electrode for medical use according to the first aspect of the present invention is formed in a closed loop by bending a linear elastic body, and a connection end where both ends of the linear elastic body are connected, and the connection end And a pair of first linear parts extending from the linearly spaced apart elastic body, and ends of the pair of first linear parts extending in the extending direction. An elastic support having a plurality of elastic members each formed with a second linear portion including at least one bent portion in the middle, and at least one of the plurality of elastic members for applying electrical stimulation through the inner wall of the blood vessel. A stimulating electrode portion arranged in one piece, a wiring electrically connected to the stimulating electrode portion, a linear extension, and the connecting end portions of the plurality of elastic members are connected to a tip member, respectively, the wire and a lead portion which is inserted, the folding in Parts are Ru includes a second bent portion V-shaped convex toward the said connection end.

  According to a second aspect of the present invention, in the medical electrostimulation electrode according to the first aspect, the elastic support member is engaged with the plurality of elastic members at the first linear portion. Accordingly, an opening surrounding the central axis is formed by the linear elastic body including the second linear part, which is formed in a bowl shape centering on the central axis of the tip member of the lead part. Also good.

  According to a third aspect of the present invention, in the medical electrical stimulation electrode according to the second aspect, the elastic support may be formed in a rotationally symmetric shape with the central axis as the axis of symmetry.

  According to a fourth aspect of the present invention, in the medical electrical stimulation electrode according to the first to third aspects, the bent portion is a V-shaped first convex in a direction away from the connecting end portion. You may provide a bending part.

According to a fifth aspect of the present invention, in the medical electrical stimulation electrode according to the first to fourth aspects, each of the plurality of elastic members covers a linear core material and the core material. And a covering member to be provided.

According to a sixth aspect of the present invention, in the medical electrical stimulation electrode according to the fifth aspect, the core material may be a super elastic wire.

According to a seventh aspect of the present invention, in the medical electrical stimulation electrode according to the fifth aspect or the sixth aspect, the plurality of elastic members are arranged such that the stimulation electrode portion is disposed and the wiring is built-in. 1 and a second elastic member that does not have the stimulation electrode portion and the wiring, and the bending rigidity of the core material in the first elastic member is determined by the core in the second elastic member. By making it lower than the bending rigidity of the material, the elastic restoring force generated in the radial direction when the elastic support is reduced by a certain amount may be equalized.

According to an eighth aspect of the present invention, in the medical electrical stimulation electrode according to the fifth aspect or the sixth aspect, the plurality of core members provided in the plurality of elastic members are two or more types having different bending rigidity. When the elastic support is reduced in diameter by a certain amount, the elastic restoring force generated in the radial direction may vary depending on the position in the circumferential direction.

  According to the electrical stimulation electrode for medical use of the present invention, even if folding is repeated, there is an effect that it can be stably placed in a blood vessel.

It is a typical block diagram which shows the structure of the medical electrical stimulation electrode of embodiment of this invention. It is a typical front view which shows the structure of the elastic support body of the medical electrical stimulation electrode of embodiment of this invention. It is a side view of A view in FIG. 2A. It is a typical perspective view which shows the structure of the elastic member of the medical electrical stimulation electrode of embodiment of this invention. It is a top view of the B view in FIG. It is a side view of C view in Drawing 4A. It is a typical front view which shows the structure of an example of the elastic member of the medical electrical stimulation electrode of embodiment of this invention. FIG. 6 is a F view in FIG. 5. It is a D view in FIG. 4B. It is the E view in FIG. 4B. It is a typical top view which shows the structure of the stimulation electrode part of the medical electrical stimulation electrode of embodiment of this invention. It is HH sectional drawing in FIG. 9A. It is JJ sectional drawing in FIG. 9A. It is KK sectional drawing in FIG. It is a G view in FIG. It is LL sectional drawing in FIG. 11A. It is a schematic diagram which shows the external appearance of a patient when the medical electrical stimulation electrode of embodiment of this invention is detained in the patient's body. It is a schematic diagram which shows the state which indwelled the medical electrical stimulation electrode of embodiment of this invention in the superior vena cava. It is a schematic diagram which shows the state of the deformation | transformation in the blood vessel of the elastic support body of the medical electrical stimulation electrode of embodiment of this invention. It is a side view of the M view in FIG. 14A. It is a side view which shows the shape of the diameter-reduced state of the elastic support body of the medical electrical stimulation electrode of embodiment of this invention. It is a side view which shows the shape of the natural state of the elastic support body of the medical electrical stimulation electrode of embodiment of this invention. It is a schematic diagram explaining the effect | action of the elastic member of the medical electrical stimulation electrode of embodiment of this invention. It is a schematic diagram explaining the effect | action of the elastic member of a comparative example. It is a typical enlarged view which shows the deformation | transformation state of the top part of the elastic member of the medical electrical stimulation electrode of embodiment of this invention, and the top part of the elastic member of a comparative example. It is a schematic diagram which shows the structure of the principal part of the elastic member used for the medical electrical stimulation electrode of the 1st modification of embodiment of this invention. It is a typical top view which shows the structure of the elastic member used for the medical electrical stimulation electrode of the 2nd modification of embodiment of this invention. It is a typical top view which shows the structure of the elastic member used for the medical electrical stimulation electrode of the 3rd modification of embodiment of this invention. It is a typical front view which shows the structure of the elastic member used for the medical electrical stimulation electrode of the 3rd modification of embodiment of this invention. It is a typical front view which shows the structure of the elastic member used for the medical electrical stimulation electrode of the 4th modification of embodiment of this invention. It is a typical top view which shows the structure of the elastic member used for the medical electrical stimulation electrode of the 5th modification of embodiment of this invention. It is a typical front view which shows the structure of the elastic member used for the medical electrical stimulation electrode of the 5th modification of embodiment of this invention.

A medical electrical stimulation electrode according to an embodiment of the present invention will be described.
FIG. 1 is a schematic configuration diagram showing a configuration of a medical electrical stimulation electrode according to an embodiment of the present invention. FIG. 2A is a schematic front view showing the configuration of the elastic support of the medical electrical stimulation electrode according to the embodiment of the present invention. FIG. 2B is a side view as viewed in A in FIG. 2A. FIG. 3 is a schematic perspective view showing the configuration of the elastic member of the medical electrical stimulation electrode according to the embodiment of the present invention. 4A is a plan view as viewed from B in FIG. 4B is a side view as seen from C in FIG. 4A. FIG. 5 is a schematic front view showing the configuration of an example of the elastic member of the medical electrical stimulation electrode according to the embodiment of the present invention. FIG. 6 is an F view in FIG. FIG. 7 is a view as viewed from D in FIG. 4B. FIG. 8 is an E view in FIG. 4B. FIG. 9A is a schematic plan view showing the configuration of the stimulation electrode portion of the medical electrical stimulation electrode according to the embodiment of the present invention. 9B is a cross-sectional view taken along line HH in FIG. 9A. 10A is a cross-sectional view taken along line JJ in FIG. 9A. 10B is a cross-sectional view taken along the line KK in FIG. FIG. 11A is a G view in FIG. 11B is a cross-sectional view taken along line LL in FIG. 11A.

An electrical stimulation system 100 shown in FIG. 1 is a system that applies electrical stimulation to surrounding nerve tissue through the inner wall of a blood vessel. The electrical stimulation system 100 is inserted into a patient's blood vessel and left in place for a certain period.
The electrical stimulation system 100 is different from a system that performs nerve stimulation over a long period of time by implanting the entire system in the body. The electrical stimulation system 100 is suitable for performing nerve stimulation for a short period of time.
The electrical stimulation system 100 includes the medical electrical stimulation electrode 1 of the present embodiment and the electrical stimulation device 8.
The medical electrical stimulation electrode 1 stimulates a nerve from within a blood vessel. The electrical stimulation device 8 applies a stimulation pulse to the medical electrical stimulation electrode 1.

The medical electrical stimulation electrode 1 includes stimulation electrodes 21 and 22 (stimulation electrode portion), a lead portion 3, and an elastic support body 2.
The stimulation electrodes 21 and 22 apply electrical stimulation through the inner wall of the blood vessel. The lead portion 3 is formed in a linear shape and passes through a wiring (not shown) electrically connected to the stimulation electrodes 21 and 22. The elastic support 2 is connected to the tip member 3 b of the lead portion 3.

The medical electrical stimulation electrode 1 is introduced into a patient's blood vessel with the lead portion 3 inserted through a tubular guide sheath 7. In the following, when the relative positions of the lead portion 3 and the guide sheath 7 are described, unless otherwise specified, the distal end (front end portion) and the rear end (rear end portion) in the insertion direction with respect to the blood vessel of the patient are simply referred to as “front end”. (Front end) "and" rear end (rear end) ".
When the elastic support 2 of the medical electrical stimulation electrode 1 is introduced into the indwelling position in the blood vessel of the patient, the elastic support 2 is introduced in a state of being folded and accommodated at the distal end portion of the guide sheath 7. When the elastic support body 2 reaches the indwelling position, the elastic support body 2 is pushed into the blood vessel from the distal end of the guide sheath 7. The elastic support 2 expands when pushed out, as will be described later. Thereby, the elastic support body 2 contacts the inner wall of the patient's blood vessel. The elastic support 2 is placed in the patient's blood vessel.
In addition, in the electrical stimulation system 100, it is preferable that an antithrombotic coating is applied to a surface that comes into contact with blood on a member or a part inserted into a blood vessel of a patient in order to suppress thrombus generation.

For example, a tube made of polyurethane or polyamide can be used as the guide sheath 7.
As an example, the dimensions of the tubular portion of the guide sheath 7 in the present embodiment are an outer diameter of 2.8 mm, an inner diameter of 2 mm, and a length of 300 mm.
A branch portion 7 b is provided at the rear end portion of the guide sheath 7. A liquid feeding pipe 6 is connected to the side of the branch part 7b. The liquid feeding tube 6 communicates with a conduit formed inside the guide sheath 7. The liquid feeding tube 6 can continuously administer a drug solution such as heparin, which is an antithrombotic agent, into the guide sheath 7.
Inside the branch part 7b, for example, a seal part 7a made of an O-ring or the like is provided. The lead portion 3 is inserted through the seal portion 7a. The seal portion 7 a maintains water tightness between the pipe line in the guide sheath 7 and the lead portion 3.
A connector 6a is provided at the end of the liquid feeding pipe 6 opposite to the branching portion 7b. As the connector 6a, a liquid feeding means (not shown), for example, a luer lock connector for connecting a syringe piston pump or the like can be adopted.

The lead portion 3 includes a lead tube 3a that is a flexible tubular member. At both ends of the lead tube 3a, a hard tip member 3b and a hard branch part 3c to which the liquid feeding pipe 5 is connected are provided.
The tip member 3 b is disposed at the first end that is the tip of the lead portion 3.
A wiring portion 3d is inserted into the lead tube 3a. The wiring part 3d is electrically connected to the stimulation electrodes 21 and 22.
The wiring part 3d extends to the outside from the opening of the branch part 3c. A connector 3e that is electrically connected to the electrical stimulation device 8 is coupled to the end of the wiring portion 3d in the extending direction. As the connector 3e, for example, a known IS1 type connector can be employed.

As the lead tube 3a, for example, a resin tube having an outer diameter of 1 mm to 3 mm and a total length of about 500 mm can be employed. The resin used for the lead tube 3a is not particularly limited. For example, a polyurethane tube having excellent biocompatibility can be adopted as the lead tube 3a.
The outer diameter of the lead tube 3a is smaller than the inner diameter of the guide sheath 7 so that a gap is formed between the inner diameter surface of the guide sheath 7 and the guide sheath 7 can be fitted to the seal portion 7a of the guide sheath 7 so as to be able to advance and retract. . For example, when the inner diameter of the guide sheath 7 is 2.8 mm, the outer diameter of the lead tube 3a is preferably about 2.5 mm.

The tip member 3 b is a tubular part that connects the elastic support 2. The tip member 3b is connected to the tip of the lead tube 3a. An engagement hole 3f extending toward the rear end is formed at the center of the front end of the front end member 3b. The engagement hole 3f engages a converging portion 27 described later of the elastic support 2.
As the hole shape of the engagement hole 3f, an appropriate shape capable of engaging the converging portion 27 around the central axis O can be adopted. In the present embodiment, the engagement hole 3f is a hexagonal hole. The hole center of the engagement hole 3f is coaxial with the central axis O.
The outer diameter of the tip member 3b is substantially the same (including the same case) as the outer diameter of the lead tube 3a. The step on the outer peripheral surface of the tip member 3b is not less than 0 mm and not more than 0.2 mm.
For this reason, the distal end member 3b can be inserted into the guide sheath 7 at the distal end portion of the guide sheath 7 so as to be able to advance and retract.
In the present embodiment, the tip member 3b is made of a titanium alloy. As the hole shape of the engagement hole 3f, a hexagonal hole is adopted corresponding to the outer shape of the converging portion 27 described later.

The lead portion 3 is inserted through the seal portion 7a at the rear end portion of the guide sheath 7 so as to be able to advance and retreat. The rear end portion of the lead portion 3 is exposed to the outside of the guide sheath 7 through the seal portion 7a.
The branch portion 3 c is provided at the rear end portion of the lead portion 3 exposed to the outside of the guide sheath 7.
The liquid feeding pipe 5 communicates with a pipe line (not shown) in the lead portion 3. The liquid feeding tube 5 can supply, for example, a chemical solution such as heparin, which is an antithrombotic agent, into the lead portion 3. A discharge port (not shown) is formed at the tip of the lead part 3. The drug solution supplied into the lead portion 3 through the liquid feeding tube 5 can be continuously administered into the blood vessel through emitted light (not shown).
A connector 5 a is provided at the end of the liquid feeding pipe 5 opposite to the lead portion 3. As the connector 5a, a liquid feeding means (not shown), for example, a luer lock connector for connecting a syringe piston pump or the like can be adopted.

The elastic support 2 includes elastic members 20A, 20B, and 20C that are formed in a closed loop by bending a linear elastic body. In the present embodiment, the elastic members 20A, 20B, and 20C are formed in a bowl shape centered on a central axis O that is obtained by extending the central axis of the tip member 3b to the tip side. Further, the elastic members 20A, 20B, and 20C are combined while being shifted in the circumferential direction, and are formed in a bowl shape having rotational symmetry about the central axis O.
Here, the circumferential direction is a direction around the central axis O.
Hereinafter, the end (end portion) of the elastic support 2 connected to the lead portion 3 is referred to as a base end (base end portion) of the elastic support 2. In the elastic support 2, the end (end) opposite to the base end (base end) of the elastic support 2 is referred to as the tip (tip) of the elastic support 2.
Further, in each part of the elastic support 2, an end (end part) close to the tip of the elastic support 2 is a tip (tip part) of each part, and an end (end part) close to the base end of the elastic support 2 is a base of each part. It is called the end (base end).

The elastic members 20 </ b> A, 20 </ b> B, and 20 </ b> C that are adjacent to each other in the circumferential direction are fixed by an elastic member fixing portion 34 (a knot portion) at an intermediate portion near the tip. The base end portions of the elastic members 20A, 20B, and 20C are all bundled and fixed to form a converging portion 27 (nodule portion).
As shown in FIGS. 2A and 2B, the outer shape of the elastic support 2 proceeds from the tip member 3b of the lead portion 3 toward the tip of the elastic support 2 along the central axis O (the left side in FIG. 2A). As the diameter gradually increases, the diameter becomes substantially constant, and further toward the tip, the diameter decreases.
The maximum outer diameter of the elastic support 2 is larger than the inner diameter of the blood vessel so that the inner wall of the blood vessel can be pressed in the blood vessel in which the elastic support 2 is placed.

The elastic support 2 is elastically deformable, but will be described below in a natural state unless otherwise specified.
Here, the natural state of the elastic support 2 is an assembled state in which deformation is negligible even if an external force does not act or acts. Since the elastic support 2 is lightweight, deformation due to its own weight can be ignored within the scope of the following description.

Hereinafter, when the relative position with respect to the elastic support 2 is described, the direction along the central axis O is the axial direction, the direction around the central axis O is the circumferential direction, and the central axis O intersects the central axis O in a plane orthogonal to the central axis O. The direction along the line is referred to as the radial direction.
In the axial direction, a side closer to the distal end member 3b may be referred to as a proximal end side, and a side farther from the distal end member 3b may be referred to as a distal end side.
In the radial direction, a direction away from the central axis O may be referred to as a radial outer side (outer side), and a direction approaching the central axis O may be referred to as a radial inner side (inner side).

  The elastic members 20A, 20B, and 20C have the same shape except that the stimulation electrodes 21 and 22 are disposed only on the elastic member 20A.

In the following, unless otherwise specified, the shape of the elastic member 20A will be described, and the description of the elastic members 20B and 20C will be omitted by attaching a common reference numeral consisting of “numerals + lowercase letters” to the same shape portion. . Further, in order to distinguish which part of each of the elastic members 20A, 20B, and 20C indicates each part, the subscripts A, B, and C are added after the lowercase letter of this symbol.
For example, the connecting end 20aB (20aC) in the elastic member 20B (20C) refers to a portion having the same shape as the connecting end 20aA in the elastic member 20A.
In addition, when it is applicable to any member and part that are distinguished by the subscripts A, B, and C, the subscripts A, B, and C are omitted for simplification of the description and drawings. There is a case. However, in the drawing, since the number of symbols increases so that it is difficult to see, only the symbols with the suffixes A, B, and C may be described.
For example, “elastic member 20” and “connecting end portion 20a” respectively represent any one of elastic members 20A, 20B, and 20C, or connecting end portions 20aA, 20aB, and 20aC. “Each elastic member 20” and “each connecting end 20a” represent all of the elastic members 20A, 20B, and 20C and all of the connecting ends 20aA, 20aB, and 20aC, respectively.

The elastic member 20A is formed in a closed loop shape by bending a single linear elastic body. In the present embodiment, the closed loop shape of the elastic member 20A is three-dimensional. Below, with reference to FIG. 3, 4A, 4B, 5, 6, 7, 8, the shape of the natural state of elastic member 20A single-piece | unit is demonstrated. Here, the natural state of the elastic member 20A alone is a state in which deformation is negligible even if an external force does not act or acts.
As shown in FIG. 3, the elastic member 20 </ b> A includes a connecting end portion 20 a </ i> A, a base end side linear portion 20 b </ i> A (first linear portion) from the first end portion E <b> 1 of the linear elastic body toward the second end portion E <b> 2. ), The bent portion 33fA (first linear portion), the second linear portion 20cA, the bent portion 33hA (first linear portion), the proximal end linear portion 20dA (first linear portion), and the connecting end portion 20eA. Are provided in this order.

The connecting end portions 20aA and 20eA are portions for fixing the elastic member 20A to the converging portion 27 described later and engaging the tip member 3b via the converging portion 27. In the present embodiment, the connecting end portions 20aA and 20eA are each linearly extended along the first axis O1. The connecting end portions 20aA and 20eA are arranged in parallel and close to each other across the first axis O1.
The coupling end portions 20aA and 20eA are engaged with the tip member 3b via the converging portion 27 so that the central axis O and the first axis O1 are coaxial.
The method for fixing the connecting end portions 20aA and 20eA and the converging portion 27 is not particularly limited. The fixing method of the connecting end portions 20aA and 20eA and the converging portion 27 can be appropriately selected according to the material of the converging portion 27. For example, adhesion, welding, caulking, or the like can be adopted as a method for fixing the connecting end portions 20aA, 20eA and the converging portion 27.

The proximal end side linear portions 20bA and 20dA are U-shaped portions extending as a whole from the distal ends of the connecting end portions 20aA and 20eA. The proximal end side linear portions 20bA and 20dA are disposed on a plane S2 including the first axis O1 and passing through the central axes of the coupling end portions 20aA and 20eA. The proximal side linear portions 20bA and 20dA are symmetrical with respect to the first axis O1 in the plane S2.
That is, as shown in FIG. 4A, the base-side linear portions 20bA and 20dA are inclined toward the distal end side (the left side in the drawing in FIG. 4A) so as to be separated from the distal ends of the coupling end portions 20aA and 20eA, respectively. It is extended in the direction. The proximal end side linear portions 20bA and 20dA are gradually separated from the first axis O1 toward the distal end side. The proximal end side linear portions 20bA and 20dA are substantially parallel to the first axis O1 (including the parallel case) at the respective distal end portions.

The proximal-side linear portion 20bA (20dA) can be configured by a curved portion, a broken line portion, or a combination of the curved portion and the broken line portion that protrudes in a direction away from the first axis O1.
In the present embodiment, as an example, the shape of the proximal-side linear portion 20bA (20dA) adopts a curved shape in which the average change rate of the inclination with respect to the first axis O1 varies between the proximal end portion and the distal end portion. In the present embodiment, the average change rate of the inclination with respect to the first axis O1 is larger in the proximal side region b1 (d1) of the proximal side linear portion 20bA (20dA) than in the distal side region b2 (d2). .
The change in curvature in the path from the base end region b1 (d1) to the second linear portion 20cA may be continuous or discontinuous. For example, the boundary between the proximal end side region b1 (d1) and the distal end side region b2 (d2), the boundary between the distal end side region b2 (d2) and the second linear portion 20cA, and the proximal end side linear portion 20bA (20dA) The curvature at the boundary between the first linear portion 20cA and the second linear portion 20cA may be continuous or discontinuous.

The curvature and direction at the distal end of the proximal end linear portions 20bA and 20dA can be appropriately set in consideration of the deformation state in the blood vessel at the indwelling position and the pressing force against the inner wall of the blood vessel.
In the present embodiment, the base end side linear portions 20bA and 20dA adopt a shape that is inclined so as to be separated from each other toward the tip. For this reason, the distal ends of the base end side linear portions 20bA and 20dA are most separated in the direction perpendicular to the first axis O1 in the natural state.

As shown in FIG. 3, the bent portion 33hA is formed in a U-shape between the distal end of the proximal side linear portion 20dA and the proximal end of a second linear portion 20cA described later. The bent portion 33hA protrudes on the opposite side to the second linear portion 20cA with respect to the plane S2.
In the present specification, the “U-shape” is not limited to a shape in which two parallel straight portions are connected by an arcuate curved portion. For example, the two straight portions may be parallel to each other non-parallel. The bending portion may be curved with a curve other than the arc. The bending portion may be constituted by a broken line made of a straight line or a curved line. Further, the curved portion may be replaced with a straight portion. For example, as in the present embodiment shown in FIG. 5, the shape composed of one straight line portion bent at the ends of two straight line portions is also “U-shaped”.
The bent portion 33hA of the present embodiment includes a first portion h1, a second portion h2, and a third portion h3.

The first portion h1 is a linear portion that is bent at the tip of the proximal end linear portion 20dA. The first portion h1 may be linear or curved. In the present embodiment, the first portion h1 is linear as an example.
An example of the bending angle φ1 of the first portion h1 can be in the range of 90 ° ± 30 °. The length of the first portion h <b> 1 is longer than the longitudinal direction of the stimulation electrode 22. Examples of the length of the first portion h1 include 4.5 mm or more and 7.0 mm or less.
Here, the bending angle φ1 is a smaller angle (an angle measured in the bending) among the angles formed by the first portion h1 and the distal end portion of the proximal end linear portion 20dA.

As shown in FIG. 5, the second portion h2 is a linear portion that is bent at the tip in the protruding direction of the first portion h1. The second portion h2 extends in parallel to the plane S2 at a position (see FIG. 4A) that is on the extension line of the proximal end side linear portion 20dA when viewed from the normal direction of the plane S2. The second portion h2 may be linear or curved. In the present embodiment, the second portion h2 is linear as an example.
Examples of the length of the second portion h2 include 3.0 mm or more and 7.0 mm or less.

The third portion h3 is a linear portion that is bent at the distal end in the extending direction of the second portion h2 and connected to the base end of the second linear portion 20cA described later. The third portion h3 may be linear or curved. In the present embodiment, the third portion h3 is linear as an example.
Examples of the bending angle φ2 of the third portion h3 include a range of 90 ° ± 30 ° (range of 60 ° or more and 120 ° or less).
Here, the bending angle φ2 is a smaller angle (an angle measured in the bending) among the angles formed by the third portion h3 and the second portion h2.

In the third portion h3, the end opposite to the second portion h2 (hereinafter referred to as the tip of the third portion h3) is located on the plane S2 in the present embodiment.
In the illustration of FIG. 5, the connecting portion between the third portion h3 and the second linear portion 20cA is drawn to be bent. However, whether or not the connection portion is bent as shown in the drawing is determined by the bending angle φ2 and the angle θ with respect to the plane S2 of the second linear portion 20cA described later. It is not essential that the connecting portion bends.
However, as shown in FIGS. 4A and 4B, the base end portion of the second linear portion 20cA described later is seen from the direction along the first axis O1 (see FIG. 4B), and becomes a plane S1 toward the distal end side. Bent in the direction you head. Here, the plane S1 is a plane that includes the first axis O1 and is orthogonal to the plane S2.
In the present embodiment, the base end portion of the second linear portion 20cA is inclined inward (near the center in FIG. 4B) by an angle ψ with respect to the normal line of the plane S2.
Further, when viewed from the direction along the normal line of the plane S2 (see FIG. 4A), the base end portion of the second linear portion 20cA is bent in the direction toward the plane S1 toward the distal end side.
For this reason, even if the sum of θ and φ2 is 180 °, the distal end portion of the third portion h3 and the proximal end portion of the second linear portion 20cA are bent in a V shape when viewed as a three-dimensional shape. ing. Further, the distal end portion of the third portion h3 and the proximal end portion of the second linear portion 20cA are bent even when viewed along the normal line of the plane S2.
A bent portion formed by the distal end portion of the third portion h3 and the proximal end portion of the second linear portion 20cA is hereinafter referred to as a bent portion 20hA.

In the bent portion 20hA having such a configuration, the stimulation electrode 22 is disposed on the first portion h1. A stimulation electrode 21 is disposed on the third portion h3.
The stimulation electrode 22 is disposed at an intermediate portion of the first portion h1 so that the longitudinal direction thereof is along the central axis direction of the first portion h1. A part of the stimulation electrode 22 is exposed on the surface that is radially outward with respect to the first axis O1.
The stimulation electrode 21 is disposed at an intermediate portion of the third portion h3 so that the longitudinal direction thereof is along the central axis direction of the third portion h3. A part of the stimulation electrode 21 is exposed on the surface that is radially outward with respect to the first axis O1.

The position of the stimulation electrode 22 (21) in the central axis direction in the first portion h1 (third portion h3) is not particularly limited as long as electrical stimulation can be applied to the nerve tissue to be stimulated. However, when it is parallel to a blood vessel like the vagus nerve P6, it is preferable to arrange so that it may oppose in the axial direction of the elastic support body 2. FIG. Although not shown, a stimulation electrode may be installed in the second portion h2 in FIG. 5, and another stimulation electrode may be installed in the second portion h2 of the bent portion 33fA described later. In this case, when each stimulation electrode is inserted into the blood vessel, the stimulation electrode can be arranged in parallel with the running of the vagus nerve P6. Moreover, it can arrange | position so that the vagus nerve P6 may be inserted | pinched with a stimulation electrode.
The detailed configuration of the stimulation electrodes 21 and 22 will be described after the elastic member 20A is further described.

  The configuration of the bent portion 33hA has been described above. As shown in FIG. 7, the bent portion 33hB (33hC) of the elastic member 20B (20C) is configured in the same manner as the bent portion 33hA, except that the stimulation electrodes 21 and 22 are omitted.

Next, the bent portion 33fA of the elastic member 20A will be described.
As shown in FIG. 8, the bent portion 33fA is formed in a U-shape between the distal end of the proximal end side linear portion 20bA and the proximal end of a second linear portion 20cA described later. Similar to the bent portion 33hA, the bent portion 33fA protrudes on the opposite side to the second linear portion 20cA with respect to the plane S2.
The bent portion 33fA of the present embodiment includes a first portion f1, a second portion f2, and a third portion f3.
The outer shape of the bent portion 33fA may be different from the bent portion 33hA provided at a position facing the plane S1 (see FIG. 3). However, in the present embodiment, the outer shape of the bent portion 33fA is plane-symmetric with the bent portion 33hA with respect to the plane S1.
That is, the first part f1, the second part f2, and the third part f3 have the same outer shape as the first part h1, the second part h2, and the third part h3 in the bent part 33hA, respectively.
Further, a bent portion 20fA similar to the bent portion 20hA is formed by the tip portion of the third portion h3 and the second linear portion 20cA.
However, unlike the bent portion 33hA, the stimulation electrodes 21 and 22 are not arranged in the bent portion 33fA.
The tip of the third portion h3 of the bent portion 33hA and the tip of the third portion f3 of the bent portion 33fA are located on the third axis O3 orthogonal to the first axis O1 on the plane S2.

  The configuration of the bent portion 33fA has been described above. As shown in FIG. 8, the bent portion 33fB (33fC) of the elastic member 20B (20C) is configured similarly to the bent portion 33fA.

  The base end side linear portion 20d and the bent portion 33h, and the base end side linear portion 20b and the bent portion 33f described above are a pair in which linear elastic bodies are extended away from the connecting end portions 20a and 20e, respectively. 1st linear part is comprised.

The second linear portion 20cA is a portion that is connected at both ends to the ends of the extending direction of the pair of first linear portions and includes at least one bent portion in the middle between both ends.
As shown in FIGS. 5 and 8, in the present embodiment, the second linear portion 20cA gradually moves away from the plane S2 from the tip of the third portions f3 and h3 in the bent portions 33fA and 33hA toward the tip side. It is extended in an oblique direction. As shown in FIG. 4A, the second linear portion 20cA is curved in a convex shape projecting toward the tip as a whole.

The second linear portion 20cA can be configured by a curved portion, a broken line portion, or a combination of the curved portion and the broken line portion that protrudes in a direction away from the third axis O3.
As shown in FIG. 4A, in the present embodiment, the shape of the second linear portion 20cA is formed in a C shape or a mountain shape that is plane-symmetric with respect to the plane S1.
The second linear portion 20cA is inclined toward the plane S1 from the tip of the third portion f3 (h3) of the bent portion 33fA (33hA) in the proximal region c1 (c3) close to the bent portion 33fA (33hA). It is extended in the shape of a curve or a straight line.
Further, in the second linear portion 20cA, a bent portion 20kA in which the linear linear portion is bent at the top portion 20gA is formed at the center of the distal end side region c2 between the proximal end side regions c1 and c3. . The top portion 20gA is located on the plane S1.
The bent portion 20kA constitutes a V-shaped first bent portion that is convex in a direction away from the connecting end portions 20aA and 20eA.

As shown in FIG. 6, the bending angle of the bent portion 20kA is θ3. The bending angle θ3 may be an obtuse angle or an acute angle.
Examples of the bending angle θ3 include a range of 5 ° to 120 °.
Within the bend of the bent portion 20 kA, there may be a curvature with a radius of curvature of 5 mm or less formed for processing.

  The shape of the distal end side region c2 excluding the bent portion 20kA may be a curved shape or a linear shape. In the present embodiment, the shape of the distal end side region c2 excluding the bent portion 20kA is, for example, a curved shape protruding outward in the radial direction with respect to the first axis O1.

As shown in FIG. 5, when the second linear portion 20cA is viewed from the direction along the third axis O3, the proximal end portion of the second linear portion 20cA with respect to the bent portion 20kA is located on the plane S3. Yes. Here, the plane S3 is a virtual plane that includes the third axis O3 and intersects the plane S2 at an angle θ.
The angle θ may be, for example, 5 ° or more and 90 ° or less.

The bent portion 20kA is inclined by an angle θ2 closer to the plane S2 than the plane S3. The angle θ2 may be an angle at which each apex 20gA contacts the inner wall of the blood vessel in a deformed state in which the elastic support 2 is inserted into the blood vessel. However, the angle θ2 may be an angle at which each apex 20gA does not contact the inner wall of the blood vessel.
The magnitude of the angle θ2 can be, for example, 5 ° or more and 90 ° or less.
In the present embodiment, bent portions 20jA are formed at the connection portions between the base end portion of the bent portion 20kA and the second linear portion 20cA excluding the bent portion 20kA.
However, in order to more firmly lock the elastic support 2 in the blood vessel, the angle θ2 may be 0 ° or an angle inclined to the opposite side with respect to the plane S3. In this case, the top portion 20gA is strongly pressed against the inner wall of the blood vessel.

  With this configuration, in the present embodiment, the outer shape of the entire elastic member 20A is a plane-symmetric shape with respect to the plane S1.

Here, the internal structure of the elastic member 20A and the configuration of the stimulation electrodes 21 and 22 will be described.
As shown in FIGS. 9A and 9B, in the elastic member 20A, the outer peripheral surface of the wire 23X (core material), which is a linear elastic body, is covered with an outer covering 26 (covering member).

As the wire 23X, an appropriate metal wire that hardly causes plastic deformation can be adopted.
Examples of the metal wire suitable as the wire 23X include a shape memory alloy and a superelastic wire. The cross-sectional shape in a direction orthogonal to the longitudinal direction of the wire 23X (hereinafter simply referred to as a cross-sectional shape) is not particularly limited. For example, a rectangular cross section or a circular cross section can be employed.
Examples of the cross-sectional shape of the wire 23X include, for example, a square cross section or a rectangular cross section with a side length of 0.1 mm to 0.3 mm, and a circular cross section with a diameter of 0.1 mm to 0.3 mm. be able to. As shown to FIG. 10A, in this embodiment, the cross-sectional shape of the wire 23X is a square.
In this embodiment, the wire 23X employs a superelastic wire of 0.27 mm × 0.27 mm as an example.

As shown in FIGS. 9A and 9B, the outer covering 26 is a covering member that forms the outermost peripheral surface of the elastic member 20 </ b> A except for the exposed portions of the stimulation electrodes 21 and 22. Therefore, when the outer covering 26 is introduced into the blood vessel, the outer peripheral surface comes into contact with blood, a living tissue such as the inner wall of the blood vessel.
For this reason, the outer covering 26 is formed of an insulating material that can be deformed together with the wire 23X and is excellent in biocompatibility. The surface of the outer coating 26 is formed smoothly so as not to cause thrombus.
Examples of a material suitable for the outer coating 26 include a polyurethane resin and a polyimide resin.
The outer covering 26 is melt-bonded so as not to include an air layer with the wire 23X by heat fusion.

The stimulation electrodes 21 and 22 differ only in the arrangement position in the elastic member 20A, and both have the same configuration.
The stimulation electrode 21 (22) is formed of a metal tube having biocompatibility such as a platinum iridium alloy, for example. A part of the stimulation electrode 21 (22) is exposed to the outer periphery of the elastic member 20A through the opening 26a of the outer covering 26. The exposed portion has a cylindrical surface shape having a curvature along the outer peripheral surface of the outer coating 26. The shape of the exposed portion viewed from the direction along the third axis O3 (viewed from the direction perpendicular to the plane of FIG. 9A) is substantially rectangular (including a rectangular shape).
In the present embodiment, as an example, a cylindrical tube member having a diameter of 0.8 mm and a length of 4 mm is employed as the stimulation electrode 21 (22). The shape of the exposed portion of the stimulation electrode 21 (22) is 0.5 mm wide and 3.8 mm long. Here, the longitudinal direction of the exposed portion coincides with the extending direction of the outer coating 26.
However, the exposed shape of the stimulation electrode 21 (22) is not limited to this. For example, the exposed shape of the stimulation electrode 21 (22) may be an oval shape or an oval shape that is long in the axial direction of the wire 23X.

A tubular insulating member 24 for preventing a short circuit with the wire 23X is inserted into the stimulation electrode 21 (22). A wire 23 </ b> X is inserted into the insulating member 24.
A wiring 25 is electrically connected to the inner peripheral surface of the stimulation electrode 21 (22) buried in the outer covering 26. The wiring 25 constitutes a wiring part 3d (see FIG. 1).
As the wiring 25, for example, a stranded wire made of a nickel cobalt alloy (35NLT25% Ag material) having bending resistance is covered with an electrical insulating material (for example, ETFE (polytetrafluoroethylene) having a thickness of 20 μm). A thing can be used suitably.
The wiring 25 is disposed in the outer covering 26 and extends along the wire 23X, and extends from the base end portion of the coupling end portions 20aA and 20eA to the rear end side of the lead portion 3 (see FIG. 11B). ).

As shown in FIG. 10B, the internal structure of the elastic members 20B and 20C includes a wire 23Y (core material) instead of the wire 23X of the elastic member 20A, and includes stimulation electrodes 21 and 22, an insulating member 24, and wiring 25. It is a deleted configuration.
The wire 23Y is made of the same material as the wire 23X. However, the wire 23Y may be different from the cross-sectional shape of the wire 23X.

Examples of the cross-sectional shape of the wire 23Y include, for example, a square cross-section or a rectangular cross-section with a side length of 0.2 mm to 0.5 mm and a circular cross-section with a diameter of 0.2 mm to 0.5 mm. be able to. As shown in FIG. 10B, in this embodiment, the cross-sectional shape of the wire 23Y is a square.
In the present embodiment, as an example, the wire 23Y employs a super-elastic wire of 0.27 mm × 0.27 mm, similar to the wire 23X.

The elastic member 20B (20C) does not have the wiring 25. Therefore, the elastic member 20B (20C) does not contribute to the bending rigidity due to the wiring 25. For this reason, if the cross-sectional shape orthogonal to the longitudinal direction of the wire 23Y (hereinafter simply referred to as the cross-sectional shape) is the same cross-sectional shape as the wire 23X, the bending rigidity of the elastic member 20B (20C) is greater than the bending rigidity of the elastic member 20A. descend.
If the cross-sectional shape of the wire 23Y is changed so that the cross-sectional secondary moment related to bending is greater than that of the wire 23X, the bending rigidity of the elastic members 20A, 20B, and 20C can be made substantially the same.
However, when the difference in bending rigidity between the wiring 25 and the outer coating 26 is small, the bending rigidity of the elastic members 20A, 20B, and 20C becomes approximately the same without changing the bending rigidity of the wires 23X and 23Y.
In the present embodiment, the cross-sectional secondary moments of the wires 23X and 23Y are the same, but the bending rigidity of the elastic members 20A, 20B, and 20C is approximately the same.

The bending stiffnesses of the elastic members 20A, 20B, and 20C do not need to be strictly matched. The flexural rigidity of each of the elastic members 20A, 20B, and 20C is such that the elastic restoring force generated in the radial direction when the elastic support 2 is reduced by a certain amount after being assembled as the elastic support 2 can be equalized. To do.
Here, “can be equalized” means that the variation in elastic restoring force is within 10%.
In the present embodiment, the elastic members 20A, 20B, and 20C are arranged rotationally symmetrical. For this reason, if the variation of each bending rigidity of elastic member 20A, 20B, 20C is kept to 10% or less, the elastic restoring force in the elastic support body 2 can be equalized.
When the diameter is reduced by a certain amount, the diameter isotropically reduced in a state where the outermost peripheral portion of the elastic support 2 is in contact with the cylindrical surface. Therefore, in this embodiment, when the blood vessel in which the elastic support 2 is disposed is cylindrical, the elastic restoring force at the time of diameter reduction can be equalized.
A certain amount when measuring the elastic restoring force can be appropriately set to a value. For example, a value close to the amount of diameter reduction when placed in the blood vessel may be used. In this case, the measured elastic restoring force is substantially equal to the pressing force acting on the blood vessel.

The elastic member 20 </ b> A constitutes a first elastic member in which a stimulation electrode portion is disposed and a wiring is incorporated.
The elastic members 20B and 20C constitute a second elastic member having no stimulation electrode portion and wiring.

Such elastic members 20A, 20B, and 20C are assembled as the elastic support 2.
Next, the arrangement of the elastic members 20A, 20B, and 20C in the natural state of the assembled elastic support 2 will be described.
As shown in FIG. 2B, in the assembled state, the elastic members 20A, 20B, and 20C have the first axis O1 aligned with the center axis O. The top portions 20gA, 20gB, and 20gC are spaced apart at equal intervals in the circumferential direction with respect to the central axis O.
In each elastic member 20, the projecting direction of the second linear portion 20 c is directed radially outward with respect to the central axis O. The arrangement order of the elastic members 20 is the order of the elastic members 20A, 20B, and 20C in the counterclockwise direction in the drawing.

In the present embodiment, the base end side linear portions 20bA and 20dB, the base end side linear portions 20bB and 20dC, and the base end side linear portions 20bC and 20dA are respectively located on the base end side by the elastic member fixing portion 64. It is fixed.
The position and length of the elastic member fixing portion 64 can be appropriately set in consideration of the balance of the pressing force during deformation. The base end side linear portions 20bA and 20dB, the base end side linear portions 20bB and 20dC, and the base end side linear portions 20bC and 20dA are not limited to the base end side, but the entire longitudinal direction is caused by the elastic member fixing portion 64. It may be fixed. Moreover, only the front end side of each base end side linear part 20b, 20d may be fixed by the elastic member fixing part 64.
In the present embodiment, as an example, the range from the distal end member 3b side to 2/3 is fixed in each of the proximal end side linear portions 20b and 20d.
Each elastic member fixing portion 64 can be formed by fusing and welding the outer coverings 26 of each elastic member 20 or bonding them with an adhesive or the like.

However, the length and forming method of the elastic member fixing portion 64 are not limited to the above.
For example, the elastic member fixing | fixed part 64 may be provided in the some dot form spaced apart in the longitudinal direction of each base end side linear part 20b, 20d.

  As shown in FIGS. 2A and 2B, the bent portions 33fA and 33hB, the bent portions 33fB and 33hC, and the bent portions 33fC and 33hA have U-shaped openings facing each other. Adjacent second linear portions 20c intersect each other. Adjacent second linear portions 20c are fixed by elastic member fixing portions 34 (nodal portions) at positions where they intersect each other.

  Thus, when the proximal end linear portions 20b and 20d of the adjacent elastic members are fixed to each other by the elastic member fixing portion 64, the proximal end linear portions 20b on the proximal end side are inserted when inserted into the blood vessel. Even if 20d is deformed, the shape of the pressing portion 35 is less likely to change when viewed from the outside in the radial direction. For this reason, the press range by the press part 35 can be stabilized.

A circular path that forms a substantially hexagonal closed loop when viewed from the direction along the central axis O by the linear portions on the distal end side of the second linear portions 20cA, 20cB, and 20cC on the distal end side of each elastic member fixing portion 34. LP is formed (see FIG. 2B). The circular path LP is a path that passes through the elastic member fixing portion 34 that is separated from the central axis O once and closes around the central axis O.
In each second linear portion 20c, a linear portion constituting a part of the circulation path LP is hereinafter referred to as a circumferential line portion CL. The circumferential line-shaped portion CL includes bent portions 20 kA, 20 kB, and 20 kC.
The circuit path LP forms an opening surrounding the central axis O in the elastic support 2 by a linear elastic body including the second linear portion.

The formation method of each elastic member fixing | fixed part 34 is not specifically limited.
For example, each elastic member fixing portion 34 may be formed by fusing and welding the outer coverings 26 of each elastic member 20. Each elastic member fixing portion 34 may be formed by bonding the outer coverings 26 of the respective elastic members 20 using an adhesive.

As shown in FIG. 2B, in this embodiment, the circulation path LP is formed in a shape that does not protrude from the cylindrical surface C0 in the natural state of the elastic support body 2.
The cylindrical surface C0 is a virtual cylindrical surface that extends along the central axis O through the elastic member fixing portion 34.
Thereby, each bending part 33h and 33f are located in the radial direction outer side of the cylindrical surface C0. The bent portions 33 h and 33 f constitute the outermost peripheral portion of the elastic support 2.
The diameter of the circumscribed cylindrical surface C1 of each of the bent portions 33h and 33f is larger than the inner diameter of the blood vessel into which the elastic support body 2 is inserted.

As shown in FIG. 2A, when a pair of bent portions 33h and 33f facing each other is viewed from the radially outer side in the radial direction, the pair spreads in a substantially hexagonal shape.
The bent portions 33 h and 33 f are located on the outermost periphery of the elastic support 2. For this reason, when the elastic support body 2 is inserted into the blood vessel, the bent portions 33h and 33f are surely brought into contact with the inner wall of the blood vessel. Each of the bent portions 33h and 33f is a portion that presses the inner wall of the blood vessel outward in the radial direction according to the deformation amount when the elastic support 2 is deformed in the blood vessel.
Hereinafter, the bent portions 33 h and 33 f that are fixed by the elastic member fixing portion 34 and make a pair are referred to as a pressing portion 35.
In each pressing portion 35, the first portions h 1, f 1 and the third portions h 3, f 3 are extended substantially along the circumferential direction of the elastic support 2. In each pressing portion 35, the second portions h <b> 2 and f <b> 2 are separated from each other in the circumferential direction and extend substantially parallel to the axial direction.
The base end of each pressing portion 35 is connected to the base end side linear portions 20d and 20b that curve inward in the radial direction toward the base end of the elastic support body 2, respectively.

  As shown in FIG. 11A, the connecting end portions 20aA, 20eA, 20aB, 20eB, 20aC, and 20eC connected to the base ends of the base end side linear portions 20bA, 20dA, 20bB, 20dB, 20bC, and 20dC are integrated by the converging portion 27. It is bundled and fixed.

For example, the converging part 27 is formed by inserting each connecting end part 20a and each connecting end part 20e into a tubular member made of a titanium alloy, followed by caulking. The outer shape of the converging portion 27 is a hexagonal column shape that can be fitted into the engagement hole 3f.
As shown in FIG. 11B, the converging part 27 is inserted into a hexagonal engagement hole 3f formed coaxially with the central axis O in the tip member 3b and engaged in the circumferential direction. The focusing portion 27 is fixed to the tip member 3b by, for example, adhesion.
As described above, the converging portion 27 and the tip member 3b are in a relationship between the shaft portion and the hole portion having hexagonal cross sections that are fitted to each other. The converging part 27 and the tip member 3b are engaged around the central axis O so as not to rotate. For this reason, when the lead part 3 is rotated around the central axis O, the elastic support 2 also rotates around the central axis O according to the rotation angle of the lead part 3.

Inside the distal end member 3b, the wiring 25 extending from the connecting end portions 20aA and 20eA (not shown in FIG. 11B) extends through the interior of the distal end member 3b and into the lead tube 3a. The wiring 25 is grouped as a wiring part 3d inside the lead tube 3a.
The position of the wiring portion 3d is fixed by a fixing portion 3g in the lead tube 3a and extends to the rear end portion of the lead tube 3a. The wiring part 3d extends to the outside from the branch part 3c (see FIG. 1).

As shown in FIG. 2B, the outer shape of the elastic support body 2 assembled in this way is a bowl-like shape having a three-fold rotational symmetry with the central axis O as the rotational symmetry axis.
Further, as shown in FIG. 2A, when viewed from the direction intersecting the central axis O, each base end side linear portion 20b and each base end side linear portion 20d can be formed by rotating a U-shape around the central axis O. They are arranged along a semi-spindle shape.
Each pressing portion 35 constitutes the outermost peripheral portion in the intermediate portion in the axial direction.
Each second linear portion 20c on the distal end side of each elastic member fixing portion 34 is disposed along a shape that decreases in diameter toward the central axis O toward the distal end side.

In the natural state of the assembled state of the elastic support 2 described above, no external force other than gravity acts on the elastic support 2. Since each elastic member 20 is lightweight, deformation of the elastic support 2 due to gravity can be ignored.
However, the elastic members 20A, 20B, and 20C intersect each other, and are fixed to each other by the elastic member fixing portion 34 at the intersecting positions. By being restrained in this way, the elastic member 20 receives an external force from the other elastic members 20.
Therefore, in the natural state of the assembled state of the elastic support body 2, each elastic member 20 is deformed into a shape different from the shape of the single natural state.

The electrical stimulation device 8 is a device portion that generates electrical stimulation between the pair of stimulation electrodes 21 and 22 based on the operation of the operator when the medical electrical stimulation electrode 1 is placed in a blood vessel. Although illustration of the detailed structure of the electrical stimulation apparatus 8 is abbreviate | omitted, the power supply and the control part are provided at least. The power supply outputs a pulsed signal waveform. A control part produces | generates the signal waveform for a power supply to output, and controls the application timing of a signal waveform.
As shown in FIG. 1, the electrical stimulation device 8 is electrically connected to the wiring portion 3 d in the lead portion 3 via a connector 3 e.
In this embodiment, the signal waveform output from the electrical stimulation device 8 is generated with a constant current system or a constant voltage system biphasic waveform group with a predetermined interval. The condition of the signal waveform can be appropriately set as necessary for electrical stimulation. Specifically, for example, it is possible to output a signal waveform such as generating a biphasic waveform with a frequency of 20 Hz and a pulse width of 50 μsec to 400 μsec from 3 to 20 seconds per minute. is there.
At the time of outputting such a signal waveform, one of the stimulation electrodes 21 and 22 acts as a plus side electrode, and the other acts as a minus side electrode.

In order to perform electrical stimulation from within a blood vessel using such an electrical stimulation system 100, for example, after the elastic support 2 of the medical electrical stimulation electrode 1 is introduced into the patient's superior vena cava and the indwelling position is searched for Indwell in the superior vena cava.
Further, when the necessary electrical stimulation is completed, the elastic support 2 is removed from the patient's body.
Below, the effect | action of the electrical stimulation system 100 is demonstrated.
FIG. 12 is a schematic view showing a state outside the patient's body when the medical electrical stimulation electrode according to the embodiment of the present invention is placed in the patient's body. FIG. 13 is a schematic view showing a state in which the medical electrical stimulation electrode according to the embodiment of the present invention is placed in the superior vena cava. FIG. 14A is a schematic diagram showing a state of deformation in the blood vessel of the elastic support of the medical electrical stimulation electrode according to the embodiment of the present invention. 14B is a side view of the M view in FIG. 14A. FIG. 15A is a side view showing the shape of the elastic support of the medical electrical stimulation electrode according to the embodiment of the present invention in a reduced diameter state. FIG. 15B is a side view showing the natural shape of the elastic support of the medical electrical stimulation electrode according to the embodiment of the present invention.

First, as shown in FIG. 12, the surgeon cuts the vicinity of the neck of the patient P to form an opening P1. A known introducer or dilator (not shown) is attached to the opening P 1, and the medical electrical stimulation electrode 1 accommodated in the guide sheath 7 is introduced together with the guide sheath 7. At this time, the medical electrical stimulation electrode 1 is introduced while confirming the positions of the wires 23X and 23Y, the wiring 25, the elastic support 2 (all not shown in FIG. 12) and the like under the X-ray.
When the distal end of the guide sheath 7 reaches the vicinity of the indwelling position in the superior vena cava P3 (blood vessel) through the right external jugular vein P2 (blood vessel), the elastic support 2 is pushed out of the guide sheath 7.
The elastic support body 2 pushed into the superior vena cava P3 expands in the superior vena cava P3 in order to return to the natural state by the elastic restoring force.
Since the outer diameter of the elastic support 2 in the natural state is smaller than the inner diameter of the superior vena cava P3, the elastic support 2 is pressed against the inner wall V1 of the superior vena cava P3.
Thereby, the elastic support body 2 is elastically deformed by the reaction from the inner wall V1. The elastic support body 2 is reduced in diameter to be smaller than the natural state. The inner wall V <b> 1 is in close contact with the outer peripheral portion of the elastic support 2 while being deformed by receiving a pressing force from the elastic support 2.
For this reason, the elastic support body 2 is locked to the inner wall V1 of the superior vena cava P3 in contact with the frictional force.

Thus, when the elastic support body 2 is roughly arranged in the superior vena cava P3, an electrical stimulation is applied to the stimulation electrodes 21 and 22, and for example, an appropriate indwelling position is searched while monitoring the heart rate of the patient P. Perform a search action. The surgeon corrects the indwelling position of the elastic support 2 as necessary.
If the lead portion 3 is rotated, the elastic support 2 is rotated together with the lead portion 3. For this reason, the operator can adjust the positions of the stimulation electrodes 21 and 22 in the circumferential direction in the superior vena cava P3.

  However, if the position of the schematic arrangement of the elastic support 2 is greatly shifted in the axial direction of the superior vena cava P3, an appropriate indwelling position may not be found. In this case, the surgeon houses the elastic support 2 again in the guide sheath 7 and moves the elastic support 2 together with the guide sheath 7.

When the positioning of the elastic support 2 is completed and the indwelling position is determined, the guide sheath 7 is pulled out to the proximal end side, and only the medical electrical stimulation electrode 1 is left in the blood vessel as shown in FIG. In this way, the placement of the elastic support 2 is completed.
If the elastic support body 2 is arrange | positioned in an appropriate placement position, the electrical stimulation apparatus 8 will apply electrical stimulation at an appropriate timing. Thereby, the electrical stimulation required for the vagus nerve P6 of the patient P can be applied via the inner wall V1.
When electrical stimulation is continuously applied to the vagus nerve P6 for a necessary period by the electrical stimulation device 8, the medical electrical stimulation electrode 1 is pulled out in the direction opposite to the inserted path. Thereby, the medical electrical stimulation electrode 1 is extracted out of the body of the patient P. At this time, since the elastic support body 2 has a shape along the semi-spindle shape whose outer peripheral portion is reduced in diameter toward the tip member 3b, it can be pulled out smoothly.

Next, the operation of the elastic support 2 will be described.
An example of the deformation state of the elastic support 2 is shown in FIGS. 14A and 14B.
The elastic support body 2 comes into contact with the inner wall V1 from a portion that is the outermost peripheral portion in the radial direction, and receives a reaction radially inward from these contact portions. As a result, the elastic members 20A, 20B, and 20C are deformed.
That is, first, each pressing portion 35 comes into contact with the inner wall V1 and is pressed radially inward. Thereby, each circumferential line-shaped portion CL is compressed radially inward via each elastic member fixing portion 34.
However, in FIG. 14B, it is schematically drawn in order to avoid the overlap of the lines and make the illustration easy to see.
Below, it demonstrates based on FIG. 15A and 15B which represented more accurately the diameter-reduced state which inserted the elastic support body 2 in the M view of FIG. 14A, and the natural state seen from the same direction.

As shown in FIG. 15A, the diameter of the elastic support 2 is reduced according to the inner wall V1 of the superior vena cava P3 until the outermost peripheral portion is inscribed in a virtual cylindrical surface C4 coaxial with the central axis O. At this time, each pressing portion 35 is inscribed in the cylindrical surface C4.
However, the base end portion of the second linear portion 20c of each pressing portion 35 is connected to each bending portion 33h (33f) via the bending portion 20h (20f) and extends toward the radially inner side. Yes. For this reason, the elastic member fixing | fixed part 34 formed in the position where these cross | intersect is located on the virtual cylindrical surface C3 smaller in diameter than the cylindrical surface C4.

15B, in the natural state of the elastic support 2 shown in FIG. 15B, each pressing portion 35 is inscribed in the circumscribed cylindrical surface C1, and each elastic member fixing portion 34 is a virtual cylindrical surface C0 having a smaller diameter than the circumscribed cylindrical surface C1. Corresponds to being located above.
When each pressing portion 35 is pressed radially inward from the natural state to reduce the diameter, the distance between the bent portions 20h and 20f that are both ends of each second linear portion 20c is reduced (see the arrow in FIG. 15B). At this time, the second linear portion 20c is bent around the top portion 20g by an external force acting on both ends of the second linear portion 20c. The top portion 20g of the second linear portion 20c moves radially outward (see the white arrow in FIG. 15B).
In such a deformation, the bending angles of the bent portions 20 h and 20 f tend to be slightly larger than the natural state of the elastic support 2. However, the state where the bent portions 20h and 20f are bent is maintained. As a result, the positional relationship in which each elastic member fixing portion 34 is located radially inward from the cylindrical surface where the bent portions 20h and 20f are located is maintained.
Therefore, the diameter of the cylindrical surface C3 in the reduced diameter state is smaller than the diameter of the cylindrical surface C4. However, the diameter difference between the cylindrical surfaces C4 and C3 is smaller than the diameter difference between the circumscribed cylindrical surface C1 and the cylindrical surface C0.

On the other hand, each apex 20g moves radially outward along with the diameter reduction of the elastic support 2, and therefore protrudes radially outward from the cylindrical surface C3 depending on the position of the elastic member fixing portion 34. In some cases, each top 20g may move radially outward from the cylindrical surface C4.
When moving radially outward from the cylindrical surface C4, the top 20g contacts the inner wall V1. When the top portion 20g moves outward in the radial direction, it is elastically deformed, and the portion where the tip end portion of the second linear portion 20c closely adheres along the inner wall V1 increases.
The position to which each top 20g moves in the reduced diameter state of the elastic support 2 depends on the shape of each elastic member 20, the position of the elastic member fixing portion 34, and the outer diameter at the time of diameter reduction. In general, the closer the distance between the bent portions 20h, 20f and the elastic member fixing portion 34, the easier the top portions 20g move outward in the radial direction.
Accordingly, if the outer diameter of the elastic support 2, the shape of each elastic member 20, and the position of the elastic member fixing portion 34 are appropriately set according to the inner diameter of the indwelling blood vessel, 20g can be in contact with the inner wall of the blood vessel or not.
In the present embodiment, each apex 20g can be brought into contact with or not in contact with the inner wall of the blood vessel by changing the angle θ2 of the bent portion 20k with respect to the plane S3.
Hereinafter, as an example, as illustrated in FIG. 15A, the description will be made on the assumption that the top portion 20g is positioned radially inward from the cylindrical surface C3 in the reduced diameter state.

Even when the elastic support 2 is reduced in diameter in the superior vena cava P3, when the diameter is reduced while maintaining a circular shape, the elastic support 2 maintains a three-fold rotationally symmetric shape with the central axis O as a rotationally symmetric axis after deformation.
As shown in FIG. 15A, as the diameter decreases, each pressing portion 35 moves in the radial direction until it is positioned on the cylindrical surface C3. As shown in FIG. 14A, in the superior vena cava P3, each pressing portion 35 abuts on the inner wall V1 of the superior vena cava P3 and forms the inner wall V1 in the radial direction at a position forming 120 ° in the circumferential direction. Press outward.
On the other hand, each circumferential line-shaped portion CL is located inside the cylindrical surface C3 where the elastic member fixing portion 34 is located, and is not in contact with the inner wall V1 of the superior vena cava P3.

Further, the circumferential line portion CL is a closed loop shape having a constant line length by being fixed by the elastic member fixing portion 34, and is a ring-shaped spring member that can expand and contract in the radial direction. For this reason, as shown in FIGS. 14A and 14B, the elastic restoring force of each circumferential line-shaped portion CL due to the deformation is applied to the elastic member fixing portion 34 even when the top portions 20g are not in contact with the inner wall V1. For this reason, each circumferential line-shaped part CL urges the pressing part 35 radially outward.
With such a configuration, each pressing portion 35 is elastically supported by each circumferential line portion CL on the distal end side of the elastic support 2. Further, each pressing portion 35 is elastically supported by the respective proximal end side linear portions 20b and 20d which are elastic members supported by the converging portion 27 on the proximal end side of the elastic support body 2.
For this reason, the elastic support body 2 in a reduced diameter state presses the inner wall V <b> 1 equally in three directions by the respective pressing portions 35.
Thus, in the elastic support body 2, the press part 35 is gathered in three places of the circumferential direction. For this reason, compared with the case where each bending part 33h and 33f are each disperse | distributed to the circumferential direction, the inner wall of the blood vessel can be pressed more firmly.
Thereby, the stimulation electrodes 21 and 22 can be more reliably and stably pressed against the inner wall V1.
Moreover, since each pressing part 35 is equally pressed radially outward by the elastic restoring force of the circumferential line-shaped part CL, the indwelling position can be stabilized even with a small contact area.

Further, the elastic support 2 of the present embodiment has an outer shape that conforms to a semi-spindle shape that swells toward the converging portion 27 as a whole, although the tip is reduced in diameter.
For this reason, compared with the shape which contact | abuts a blood vessel only in the middle part of a longitudinal direction, such as a shape along circular shape and a spindle shape, the site | part which the pressing force to the inner wall V1 generate | occur | produces in the elastic support body 2 increases. For this reason, when pressing the same pressing range with the same pressing force, further downsizing can be achieved.
Each elastic member 20 forms a bowl-like structure fixed by the elastic member fixing portion 34. Therefore, an external force received by one elastic member 20 is transmitted to the other elastic members 20 through the elastic member fixing portion 34. As a result, the elastic members 20 are deformed in conjunction with each other, and the amount of deformation is dispersed between the elastic members 20.
Thereby, even when the specific elastic member 20 receives external force, the semi-spindle-shaped rotationally symmetric shape is not easily broken. For this reason, the elastic support body 2 can urge the inner wall V1 more stably as compared with a case where, for example, arc-shaped elastic members are spaced apart in the circumferential direction.

By the way, as described above, the elastic support 2 may move in the axial direction of the blood vessel in the process of determining the indwelling position. For this reason, the elastic support 2 may be repeatedly housed in the guide sheath 7 and pushed out from the guide sheath 7.
When the elastic support body 2 is accommodated in the guide sheath 7, the elastic support body 2 is drawn into the guide sheath 7 having a smaller diameter than the blood vessel from the expanded diameter state in the blood vessel. Thereby, in the elastic support body 2, each elastic member 20 is crushed in the radial direction toward the central axis O.

Since each proximal end side linear part 20b, 20d has a shape that narrows toward the proximal end side, when accommodated in the guide sheath 7, it is accommodated smoothly, and the partial load is small.
However, the elastic support body 2 has a larger diameter toward the tip, and each circumferential line-shaped portion CL resists deformation at the tip as a spring member.
Thus, when the elastic support body 2 is accommodated in the guide sheath 7 from the expanded diameter state, a particularly large load is applied to the distal end side of each elastic member 20 of the elastic support body 2.

For the sake of simplicity, the operation of the elastic support 2 at the time of the diameter reduction will be described with an example of the elastic member 20A.
FIG. 16 is a schematic diagram for explaining the operation of the elastic member of the medical electrical stimulation electrode according to the embodiment of the present invention. FIG. 17 is a schematic diagram for explaining the operation of the elastic member of the comparative example. FIG. 18 is a schematic enlarged view showing a deformed state of the top of the elastic member of the medical electrical stimulation electrode according to the embodiment of the present invention and the top of the elastic member of the comparative example.

FIG. 16A schematically shows the shape of the elastic member 20 </ b> A in the natural state of the elastic support 2. The elastic support 2 constitutes a closed loop, and the bending angle θ3 ′ of the bent portion 20kA is slightly smaller than each of the bendings θ3 in the natural state of the elastic member 20A. The reason why the bending angle is θ3 ′ is that, in the assembled state of the elastic support 2, the elastic member 20A is fixed to the elastic members 20B and 20C and elastically deformed.
As shown in FIG. 16B, when the elastic support 2 is accommodated in the guide sheath 7, the elastic support 2 is reduced in diameter. The widest bent portions 20hA and 20fA in the elastic support 2 move toward the central axis O and come into contact with the inner wall of the guide sheath 7.
An external force acts on the second linear portion 20cA toward the central axis O at both ends connected to the bent portions 20hA and 20fA. This external force acts as a bending moment on the center in the longitudinal direction of the second linear portion 20cA. In the bent portion 20kA, the vicinity of the top portion 20gA is bent in advance. That is, a crease is attached in the vicinity of the top portion 20gA.
As described above, since the bent portion 20kA is bent by the elastic member 20A, the bending angle is easily reduced. As a result, the second linear portion 20cA is smoothly folded around the top portion 20gA. The bending angle θ3 ′ of the bent portion 20kA gradually decreases to θ4 close to 0 °.

As described above, the deformation of the elastic support 2 at the time of the diameter reduction has been described in the example of the elastic member 20A, but the deformation of the elastic members 20B and 20C is the same.
For this reason, even when an excessive external force is partially applied from the opening of the guide sheath 7 or the like when the elastic support body 2 is pulled into the guide sheath 7, the deformation resistance in each second linear portion 20 c is bent. Compared to the case without 20k. For this reason, the stress and strain of each elastic member 20 are easily dispersed throughout the elastic support 2. In other words, the diameter of the elastic support 2 can be reduced smoothly without the load being concentrated on a part of the elastic support 2.

Thus, when the diameter of the elastic support 2 is reduced, plastic deformation of the elastic support 2 is suppressed.
Therefore, when the elastic support 2 is pushed out from the guide sheath 7 and expanded in diameter, as shown in FIG. 16C, the elastic support 2 returns to the natural state when no external force is applied. For example, the bending angle of the bent portion 20 kA returns from θ4 to θ3 ′.
In this way, the elastic support 2 only repeats elastic deformation even if it is repeatedly housed in the guide sheath 7 and pushed out from the guide sheath 7, so that the pressing force that presses the inner wall of the blood vessel decreases. There is nothing to do.
Since the medical electrical stimulation electrode 1 includes such an elastic support 2, the medical electrical stimulation electrode 1 can be stably placed in the blood vessel even if the folding is repeated.

The operation of the elastic support 2 will be further described in comparison with a comparative example.
The elastic support of the comparative example includes elastic members 50 shown in FIG. 17A in place of the elastic members 20A, 20B, and 20C.
The elastic member 50 includes a second linear portion 50c instead of the second linear portion 20cA of the elastic member 20A. The second linear portion 50c is a linear portion made of an arc. Although not particularly illustrated, the second linear portion 50c is inclined by an angle θ with respect to the plane S2 in the natural state, like the second linear portion 20cA excluding the bent portion 20kA.
Both ends of the second linear portion 50c are connected to the bent portions 20hA and 20fA in the same manner as the second linear portion 20cA.
The diameter of the second linear portion 50c in the natural state of the elastic member 50 is larger than the outer diameter of the elastic support in the natural state.
The 2nd linear part 50c is provided with the top part 50g which is a part of circular arc in the position used as the front-end | tip of an elastic support body.

The effect | action at the time of diameter reduction of the elastic support body of a comparative example is demonstrated. FIG. 17A schematically shows one elastic member 50 in the natural state of the elastic support of the comparative example.
Since the elastic member 50 is slightly elastically deformed in the natural state of the elastic support, the second linear portion 50c is slightly different from the natural arcuate shape of the elastic member 50. However, since the amount of deformation is small, the vicinity of the top portion 50g of the second linear portion 50c is substantially arc-shaped.
As shown in FIG. 17B, when the elastic support body of the comparative example is accommodated in the guide sheath 7, the elastic member 50 also moves toward the central axis O and abuts against the inner wall of the guide sheath 7.
In such a diameter reduction process, the same external force as the second linear portion 20cA acts on the second linear portion 50c.
Since the second linear portion 50c is the same as the substantially arc-shaped beam, the external force acting on the second linear portion 50c deforms each position acting in the longitudinal direction of the second linear portion 50c substantially evenly. .
For this reason, the 2nd linear part 50c resists the 2nd linear part 50c whole with respect to external force. That is, the curvature of the second linear portion 50c gradually increases, and the curved shape gradually changes.

As the diameter decreases and the amount of deformation of the second linear portion 50c increases, the portion where the load increases is concentrated in the intermediate portion of the second linear portion 50c including the top portion 50g. Since the inner diameter of the guide sheath 7 is much smaller than the outer diameter of the elastic support, the distal end of the second linear portion 50c must be bent below the inner diameter of the guide sheath 7.
Since the vicinity of the top portion 50g in the natural state is an arc having a small curvature, it is substantially the same as the bent portion opened at about 180 °. For this reason, the amount of deformation in the vicinity of the top 50g when the diameter is reduced is larger than that of the second linear portion 20cA that is deformed from the bending angle θ3 ′ smaller than 180 °.
For this reason, a large stress is concentrated on the distal end portion of the second linear portion 50c as compared with the second linear portion 20cA, and plastic deformation occurs.

As shown in FIG. 18 (a), the second linear portion 20cA is formed with a bent portion 20kA, and the top portion 20gA is composed of a plastically processed corner 20 portion G.
When a deformation that reduces the bending angle of the bent portion 20kA occurs, the linear elastic body extending from the corner portion 20G is deformed as a beam having the corner portion 20G as a support end.
For this reason, even if the elastic deformation of the corner portion 20G is very small, the bending angle changes greatly because the beam bends. For example, looking at the deformed shape shown by the two-dot chain line in FIG. 18A, the deformed state is obtained even if the outside of the corner portion 20G does not extend so much and the inside of the bend is not compressed so much. I understand that.
Therefore, plastic deformation does not occur in the corner portion 20G, and the bending angle can return to the natural state.

On the other hand, as shown in FIG. 18B, the second linear portion 50c of the comparative example has an arc shape with a small curvature in the natural state indicated by the solid line.
It can be seen that in order for the second linear portion 50c to be in a reduced diameter state indicated by a two-dot chain line, extremely large bending deformation needs to occur locally in the vicinity of the top portion 50g.

As a result, as shown in FIG. 17B, the second linear portion 50c is accommodated in the guide sheath 7 in a state of being bent at an angle θ5, for example, in the vicinity of the top portion 50g.
The angle θ5 is approximately the same as the bending angle θ4 when the elastic support 2 is accommodated.
Since the top portion 50g is plastically deformed, as shown in FIG. 17C, even if the elastic member 50 is taken out from the guide sheath 7, an angle θ6 (however, θ6> θ5) is present in the vicinity of the top portion 50g. An open bend is formed. The vicinity of the top 50g does not return to the original arc.
For this reason, in the elastic support body of the comparative example, when the housing in the guide sheath 7 and the extrusion from the guide sheath 7 are repeated, the outer diameter of the elastic support body 2 gradually decreases. Thereby, the pressing force to the blood vessel is reduced, and there is a possibility that it cannot be stably placed on the inner wall of the blood vessel.

[First Modification]
Next, a first modification of the present embodiment will be described.
FIG. 19 is a schematic diagram illustrating a configuration of a main part of an elastic member used for the medical electrical stimulation electrode according to the first modification of the embodiment of the present invention.

  The medical electrostimulation electrode of this modification is provided with an elastic member 60 whose main part is shown in FIG. 19 in place of the elastic members 20A, 20B, and 20C in the medical electrostimulation electrode 1 of the above embodiment. Hereinafter, a description will be given focusing on differences from the above embodiment.

As shown in FIG. 19, each elastic member 60 of the present modification includes a bent portion 60 k instead of the bent portion 20 k of the elastic member 20. One of the elastic members 60 includes the stimulation electrodes 21, 22 and the like, similarly to the elastic member 20A.
The bending portion 60k is the same as the bending portion 20k except that a bending portion having a radius of curvature R (where R> 0) is formed in the bending when bending is performed.
The radius of curvature R in the bending of the bent portion 60k is not particularly limited as long as it is equal to or less than the bending radius R determined from the maximum arc that can be inserted into the guide sheath 7. Here, the maximum arc that can be inserted into the guide sheath 7 is an arc having a radius of curvature that is ½ of the inner diameter of the guide sheath 7. The maximum value of the radius of curvature R in bending may be obtained by subtracting the thickness of the elastic member 60 from the radius of curvature of such an arc.
However, the radius of curvature R is preferably as small as possible. When inserted into the superior vena cava P3, considering that the inner diameter of the guide sheath 7 is about 3 mm, for example, it can be set to 0.5 mm or more and 2 mm or less.

  As described above, according to the elastic member 60 of the present modification, by setting the radius of curvature R in the bending of the bent portion 60k within an appropriate range, the elastic deformation of the elastic support of the present modification when the diameter is reduced can be prevented. Can be prevented. For this reason, according to the medical electrical stimulation electrode of this modification using the elastic member 60, even if folding is repeated, it can be stably placed in the blood vessel.

  Further, according to the present modification, the bending portion of the apex portion 20g of the bent portion 60k of the elastic member 60 is a curved portion having a radius of curvature R. For this reason, when forming the bending part 60k, the bending process of the vicinity of the top part 20g becomes easy. In addition, as the linear elastic body used for the elastic member 60, it is possible to employ a material that is difficult to be plastically deformed.

[Second Modification]
Next, a second modification of the present embodiment will be described.
FIG. 20 is a schematic plan view showing a configuration of an elastic member used for the medical electrical stimulation electrode of the second modified example of the embodiment of the present invention.

  The medical electrostimulation electrode of this modification includes an elastic member 70 shown in FIG. 20 in place of the elastic members 20A, 20B, and 20C in the medical electrostimulation electrode 1 of the above embodiment. Hereinafter, a description will be given focusing on differences from the above embodiment.

As shown in FIG. 20, each elastic member 70 of the present modification includes a bent portion 70 k instead of the bent portion 20 k of the elastic member 20. One of the elastic members 70 includes stimulation electrodes 21 and 22 and the like, similarly to the elastic member 20A.
The bent portion 70k is a bent portion that opens in a V shape from the top portion 20g toward the proximal end side of the elastic member 70. The bent portion 70k constitutes a V-shaped first bent portion that is convex in a direction away from the connecting end portions 20a and 20e.
The bending angle θ7 of the bent portion 70k is smaller than the bent angle θ3 of the bent portion 20k of the above embodiment. On the other hand, the shape of the 2nd linear part 20c except the bending part 70k is the same as that of the said embodiment. For this reason, the bent part 70k is formed with a bent part 70j at the connection part with the second linear part 20c.
The bent portion 20j in the above embodiment is formed by inclining the bent portion 20k by an angle θ2 with respect to the plane S3. For this reason, the bent part 20j is a linear part smoothly connected when viewed from the direction along the normal line of the plane S3 by rotating the bent part 20k so that the angle θ2 becomes 0 °.
However, the bent portion 70j is bent in a V shape when viewed from the direction along the normal line of the plane S3 by rotating the bent portion 70k so that the angle θ2 becomes 0 °. That is, the bending angle θ8 at the bending portion 70j is smaller than the bending angle at the bending portion 20j.
In this way, the bending portion 70j has an opening angle between the bent portion 70k and the second linear portion 20c as viewed from the direction along the normal line of the plane S3. It is smaller than the opening angle with the part 20c. Therefore, as shown in FIG. 20, the opening angle between the bent portion 70k and the second linear portion 20c viewed from the direction along the normal line of the plane S2 (the vertical direction in the drawing) is also the bent portion of the above embodiment. The opening angle between 20k and the second linear portion 20c is small.

According to the present modification, the bending angle θ7 of the bent portion 70k is smaller than that in the above embodiment, and therefore the load on the top 20g is further reduced when the elastic support of the present modification is reduced in diameter. For this reason, even if the diameter reduction and the diameter expansion are repeated, the plastic deformation in the top portion 20g is further less likely to occur.
According to the medical electrical stimulation electrode of this modification using the elastic member 70, even if folding is repeated, it can be stably placed in the blood vessel.

  Further, according to this modification, the bent portion 70j is formed in the vicinity of the bent portion 70k of the elastic member 70. The bent portion 70j is further bent than the bent portion 20j of the above-described embodiment when viewed from the direction along the normal line of the plane S2. For this reason, when the diameter of the elastic support of the present modification is reduced, the bending angle of the bent portion 70j is expanded, so that the deformation stress during the diameter reduction is dispersed. Also in this respect, since the load on the top portion 20g is relieved, plastic deformation in the top portion 20g is further difficult to occur.

[Third Modification]
Next, a third modification of the present embodiment will be described.
FIG. 21 is a schematic plan view showing a configuration of an elastic member used for the medical electrical stimulation electrode of the third modified example of the embodiment of the present invention. FIG. 22 is a schematic front view showing a configuration of an elastic member used for the medical electrical stimulation electrode of the third modified example of the embodiment of the present invention.

  The medical electrostimulation electrode of this modification includes an elastic member 80 shown in FIG. 21 in place of the elastic members 20A, 20B, and 20C in the medical electrostimulation electrode 1 of the above embodiment. Hereinafter, a description will be given focusing on differences from the above embodiment.

As shown in FIG. 21, each elastic member 80 of the present modification includes bent portions 80k and 80n instead of the bent portion 20k of the elastic member 20. One of the elastic members 80 includes stimulation electrodes 21, 22 and the like, like the elastic member 20A.
The bent portion 80k is a bent portion that opens in a V shape from the top portion 20g toward the proximal end side of the elastic member 80. The bent portion 80k constitutes a V-shaped first bent portion that is convex in a direction away from the connecting end portions 20a and 20e.
The bent portion 80n is a V-shaped bent portion in which a linear elastic body extending from the bent portion 80k is bent at the bent portion 80m. The bent portion 80n is connected to the second linear portion 20c at the bent portion 80p.
The bent portions 80n are respectively formed on the sides of the bent portion 80k.
Each of the bent portions 80n constitutes a V-shaped second bent portion that is convex in a direction approaching the connecting end portions 20a and 20e.

The bending angles of the bent portions 80k and 80n are not particularly limited. Further, the bending angles of the bent portions 80k and 80n may be the same or different from each other. Each bending angle can be made smaller than the bending angle θ3 of the above embodiment.
As shown in FIG. 22A, the bent portions 80k and 80n are inclined by an angle θ2 with respect to the plane S3, as in the above embodiment. That is, the bent portions 80k and 80n are located on the same plane.

The elastic support in the medical electrical stimulation electrode according to this modification includes an elastic member 80 having bent portions 80k and 80n. For this reason, when the diameter of the elastic support is reduced, both of the bent portions 80k and 80n are elastically deformed so that the bending angle is reduced. For this reason, when the load similar to the said embodiment acts at the time of diameter reduction, a load is disperse | distributed to the top part 20g and the bending parts 80m and 80p. For this reason, even if the diameter reduction and the diameter expansion are repeated, the plastic deformation in the top portion 20g is further less likely to occur.
For this reason, according to the medical electrical stimulation electrode of this modification using the elastic member 80, even if folding is repeated, it can be stably placed in the blood vessel.

  Moreover, according to this modification, the bending part 80n is arrange | positioned rather than the bending part 80k at the base end side of the elastic member 20. FIG. For this reason, it is possible to provide a plurality of bent portions having a shallow bending angle without increasing the axial length of the elastic support. As a result, it is possible to reduce the size of the elastic support for the medical electrical stimulation electrode.

  This modification is an example in which the bent portion 80n does not have to have the top portion (bent portion 80m) on the plane S1 that is the symmetrical surface of the elastic member.

[Fourth Modification]
Next, a fourth modification of the present embodiment will be described.
FIG. 23 is a schematic front view showing a configuration of an elastic member used for the medical electrical stimulation electrode of the fourth modified example of the embodiment of the present invention.

  The medical electrostimulation electrode of this modification includes an elastic member 81 shown in FIGS. 21 and 22 in place of the elastic members 20A, 20B, and 20C in the medical electrostimulation electrode 1 of the above embodiment. Hereinafter, the points different from the above embodiment and the third modification will be mainly described.

As shown in FIG. 21, each elastic member 81 of the present modification includes bent portions 80k and 80n in the same manner as in the third modified example, instead of the bent portion 20k of the elastic member 20. One of the elastic members 80 includes stimulation electrodes 21, 22 and the like, like the elastic member 20A.
However, in this modification, as shown in FIG. 23, the bent portion 80n is located on the plane S3. Therefore, a bent portion 80j is formed between the top portion 20g and the bent portion 80m.

  This modification is the same as the third modification except that the bent portions 80k and 80n are not located on the same plane. For this reason, according to the medical electrical stimulation electrode of this modification using the elastic member 81, even if folding is repeated, it can be stably placed in the blood vessel.

[Fifth Modification]
Next, a fifth modification of the present embodiment will be described.
FIG. 24 is a schematic plan view showing a configuration of an elastic member used for the medical electrical stimulation electrode of the fifth modified example of the embodiment of the present invention. FIG. 25 is a schematic front view showing a configuration of an elastic member used for the medical electrical stimulation electrode of the fifth modified example of the embodiment of the present invention.

  The medical electrostimulation electrode of this modification includes an elastic member 90 shown in FIG. 24 instead of the elastic members 20A, 20B, and 20C in the medical electrostimulation electrode 1 of the above embodiment. Hereinafter, a description will be given focusing on differences from the above embodiment.

As shown in FIG. 24, each elastic member 90 of this modification includes a bent portion 90k instead of the bent portion 20k of the elastic member 20. One of the elastic members 90 includes stimulation electrodes 21 and 22 and the like, like the elastic member 20A.
The bent portion 90k is formed in a V shape having a top portion 90g on the base end side. The top 90g is located on the plane S1.
The end of the bent portion 90k opposite to the top 90g is connected to the second linear portion 20c via the bent portion 90m. The bending angle at the top 90g of the bent portion 90k is θ9. The bending angle θ9 can be the same angle as θ3 in the above embodiment.
Within the bend of the bent portion 90k, there may be a curvature with a radius of curvature of 5 mm or less formed for processing convenience.

As shown in FIG. 25, the bent portion 90k is inclined by an angle θ2 with respect to the plane S3, like the bent portion 20k of the above embodiment.
The bent portion 90k constitutes a V-shaped second bent portion that is convex in a direction approaching the connecting end portions 20aA and 20eA. This modification is an example in which the second linear portion 20c has only the second bent portion.

The elastic support in the medical electrical stimulation electrode according to this modification includes an elastic member 90 having a bent portion 90k. For this reason, when the diameter of the elastic support is reduced, it is elastically deformed so that the bending angle of the bent portion 90k is reduced. The bent portion 90k differs from the bent portion 20k of the above-described embodiment mainly in the convex direction. For this reason, the load at the time of diameter reduction is disperse | distributed by the elastic deformation of the bending part 90k similarly to the said embodiment, and the plastic deformation of the top part 90g is suppressed.
For this reason, according to the medical electrical stimulation electrode of this modification using the elastic member 90, even if folding is repeated, it can be stably placed in the blood vessel.

  As mentioned above, although embodiment (including a modification) of this invention was described, the technical scope of this invention is not limited to the said embodiment, The combination of a component is changed in the range which does not deviate from the meaning of this invention. It is possible to make various changes to each component or delete them.

  For example, in the description of the above-described embodiment, the example in which the stimulation electrode unit is arranged in the superior vena cava to stimulate the vagus nerve is described as an example. The stimulation electrode unit may stimulate nerves other than the vagus nerve. In this case, the stimulation electrode unit can be disposed in an appropriate blood vessel that can transmit the stimulation to the nerve that performs the stimulation.

In the description of the above embodiment, the example has been described in which the elastic support has a shape that is three-fold rotationally symmetric about the central axis. However, the elastic support can also have a rotationally symmetric shape of three or more times.
However, strict rotational symmetry is not required as long as the elastic support can apply a substantially equal pressing force to the inner wall of the blood vessel when the diameter of the elastic support is reduced.
For example, a substantially rotationally symmetric shape in which the shape of each elastic member is not symmetrical due to variations due to manufacturing errors or distortion due to assembly errors is also possible.
Further, although the overall shape is close to rotational symmetry, a substantially rotationally symmetric shape having a shape portion that does not have rotational symmetry in part is also possible. For example, the formation position of the pressing part is formed at a position that divides the circumferential direction into three equal parts, but the shape of the pressing part is different, or the pressing part is slightly different from the position that divides the circumferential direction into three equal parts Etc. are acceptable.

In the description of the above embodiment, the base end side linear portions 20b and 20d of the adjacent elastic members are described as an example in which the elastic member fixing portions 64 are fixed to each other. However, the elastic member fixing portion 64 may be deleted, and the proximal side linear portions 20b and 20d may be separated from each other in the circumferential direction.
With such a configuration, since the elastic restoring force due to the deformation of the proximal end side linear portions 20b and 20d is distributed in the circumferential direction of the inner wall of the blood vessel, the load on the inner wall of the blood vessel can be further reduced.

  In the description of the above-described embodiment, an example in which the wires 23X and 23Y are covered with the outer covering 26 has been described. However, as the wires 23X and 23Y, a linear body in which metal wires are coated with a resin can be employed. Since the resin coating in this case is further covered with the outer coating 26, it does not come into direct contact with the living body, and therefore an appropriate resin material can be employed.

In the description of the above embodiment, an example has been described in which the bending rigidity of the wire 23X, which is the core material in the first elastic member, is the same as the bending rigidity of the wire 23Y, which is the core material in the second elastic member.
However, as described above, if the bending rigidity of the wires 23X and 23Y is changed, the bending rigidity of each of the elastic members 20A, 20B, and 20C can be easily made equal. For example, the cross-sectional shape of the wire 23Y is changed so that the cross-sectional secondary moment related to bending is larger than that of the wire 23X. In this case, even when the contribution to the bending rigidity of the wiring 25 is large, the bending rigidity of the elastic members 20A, 20B, and 20C can be made substantially the same. Furthermore, it is also possible to make each bending rigidity of elastic member 20A, 20B, 20C correspond.
The method of changing the cross-sectional shapes of the wires 23X and 23Y may be changed to be similar to each other or may be changed by using different shapes. In the case of a non-similar shape, for example, the long side and the short side may be arbitrarily changed in a rectangular cross section. Furthermore, when making it a non-similar shape, you may change the kind of cross-sectional shape. For example, appropriate combinations such as one having a rectangular cross section, the other having a circular cross section, one having a circular cross section, and the other having an elliptic cross section are possible. The types of cross-sectional shapes are not limited to rectangles, circles, and ellipses, and other cross-sectional shapes are possible.
However, the method of changing the bending rigidity of the wires 23X and 23Y is not limited to changing the second moment of section. For example, the bending rigidity of each other may be changed by manufacturing the wires 23X and 23Y using materials having different longitudinal elastic modulus. Furthermore, you may change both the cross-sectional secondary moment and longitudinal elastic modulus of the wires 23X and 23Y.
Furthermore, you may change the bending rigidity of a 1st elastic member and a 2nd elastic member by changing the material and external shape of the outer coating | cover 26. FIG.

In the description of the above embodiment, the elastic members 20A, 20B, and 20C have the same bending rigidity. did.
However, by making the bending rigidity of the elastic members 20A, 20B, and 20C uneven, the elastic restoring force when the diameter of the elastic support 2 is reduced by a certain amount may be made uneven in the circumferential direction. In this case, the bending rigidity of the elastic members 20A, 20B, and 20C may be two types. Further, all of the bending rigidity of the elastic members 20A, 20B, and 20C may be different.
For example, when the cross-sectional shape of the blood vessel is deviated from a perfect circle, if the elastic restoring force is equalized when the diameter is reduced to match the perfect circular cross-section, an uneven pressing force acts on the inner wall of the blood vessel. . Thus, if the pressing force acting on the inner wall of the blood vessel is uneven in the circumferential direction, the position of the elastic support 2 may become unstable when the patient moves.
However, if the elastic restoring force when the diameter is reduced in accordance with the circular cross-section in advance is appropriately non-uniform, when the elastic support 2 is deformed to match the cross-sectional shape of the blood vessel, It is possible to equalize the pressing force acting on the inner wall in the circumferential direction. In this case, even when the cross-sectional shape of the blood vessel is deviated from a perfect circle, the position of the elastic support 2 can be stabilized.

  In the description of the above embodiment, an example in which a bent portion is formed in a part of the second linear portion 20c has been described. However, for example, the entire second linear portion 20c can be configured only by a bent portion formed in a V shape having a top at the tip.

  Although the said embodiment and the said 2nd modification-the 5th modification demonstrated by the example in case the top part of a bending part consists of a bending part, all are the internal diameters of the guide sheath 7 like the said 1st modification. Compared to the above, a curved portion having a smaller radius of curvature can be formed in the bend.

  As mentioned above, although preferred embodiment of this invention was described with various modifications, this invention is not limited to the description mentioned above, and is limited only by the scope of the attached claim.

  According to the above-described embodiments (including modifications), it is possible to provide a medical electrical stimulation electrode that can be inserted into a blood vessel and stably placed.

DESCRIPTION OF SYMBOLS 1 Medical electrical stimulation electrode 2 Elastic support body 3 Lead part 3b Tip member (end part of lead part)
8 Electrical stimulator 20, 20A, 20B, 20C, 50, 60, 70, 80, 81, 90 Elastic member 20a, 20aA, 20aB, 20aC, 20e, 20eA, 20eB, 20eC Connecting end 20b, 20bA, 20bB, 20bC 20d, 20dA, 20dB, 20dC Base end side linear portion (first linear portion)
20c, 20cA, 20cB, 20cC, 50c Second linear portion 20f, 20fA, 20fB, 20fC, 20h, 20hA, 20hB, 20hC, 20j, 20jA, 20jB, 20jC, 33f, 33fA, 33fB, 33fC, 33h, 33hA, 33hB, 33hC, 70j, 80j, 80m, 80p, 90m Bending part 20g, 20gA, 20gB, 20gC, 50g, 90g Top part 20G Corner part 20k, 20kA, 20kB, 20kC, 60k, 70k, 80k Bending part (first bending part) Part)
80n, 90k bent part (second bent part)
21, 22 Stimulation electrode (stimulation electrode part)
23, 23X, 23Y Wire (core material)
25 Wiring 26 Outer coating (coating material)
27 Focusing part (nodule part)
34 Elastic member fixing part (knot part)
35 Pressing portion 64 Elastic member fixing portion 100 Electrical stimulation system CL Circumferential line portion LP Circulating route (opening portion)
O central axis O1 first axis O2 second axis O3 third axis P patient P3 superior vena cava (blood vessel)
P6 Vagus nerve (nerve)
V1 inner wall

Claims (8)

A linear elastic body is bent to form a closed loop, and a connection end where both ends of the linear elastic body are connected, and the linear elastic body extends away from the connection end. A pair of first linear parts, and a second linear part having both ends connected to the extending ends of the pair of first linear parts and including at least one bent part in the middle of the both ends; , And an elastic support having a plurality of elastic members formed respectively,
A stimulation electrode portion disposed on at least one of the plurality of elastic members for applying electrical stimulation through the inner wall of the blood vessel;
Wiring electrically connected to the stimulation electrode portion;
A lead portion that extends in a linear shape, is connected to each of the connecting end portions of the plurality of elastic members at a tip member, and has the wiring inserted therein;
Equipped with a,
The bent portion is
Ru comprising a second bent portion V-shaped convex toward the said connection end,
Medical electrical stimulation electrode. The elastic support is
The plurality of elastic members are formed in a hook shape centered on a central axis of the tip member of the lead portion by being engaged with each other in the first linear portion,
The medical electrical stimulation electrode according to claim 1, wherein an opening surrounding the central axis is formed by the linear elastic body including the second linear portion. The elastic support is
The medical electrical stimulation electrode according to claim 2, wherein the medical electrical stimulation electrode is formed in a rotationally symmetric shape with the central axis as a symmetry axis. The bent portion is
The medical electrical stimulation electrode according to any one of claims 1 to 3, further comprising a V-shaped first bent portion that protrudes in a direction away from the connection end. Each of the plurality of elastic members is
A linear core,
A covering member for covering the core material;
The medical electrical stimulation electrode according to any one of claims 1 to 4 , further comprising: The core material is
The medical electrical stimulation electrode according to claim 5 , which is a super elastic wire. The plurality of elastic members are:
A first elastic member in which the stimulation electrode portion is disposed and the wiring is embedded;
A second elastic member not having the stimulation electrode portion and the wiring;
Consists of
When the bending strength of the core material in the first elastic member is made lower than the bending rigidity of the core material in the second elastic member, the elastic support body is reduced in diameter by a certain amount, and the radial direction The elastic restoring force generated in the
The medical electrical stimulation electrode according to claim 5 or 6 . The plurality of core members provided in the plurality of elastic members are:
It consists of two or more core materials with different bending rigidity,
The elastic support is
The medical electrical stimulation electrode according to claim 5 or 6 , wherein the elastic restoring force generated in the radial direction when the diameter is reduced by a certain amount varies depending on the position in the circumferential direction.

Images