JP2021053131A - Medical device - Google Patents

Abstract

To provide a medical device that can reduce operation load on an electrode part.SOLUTION: A medical device 10 includes: a long shaft part 20; and an electrode part 21 disposed in a distal end part of the shaft part 20 and capable of being extended in a radial direction. The shaft part 20 includes: a proximal end support part 31 for fixing a proximal end part of the electrode part 21; and a distal end support part 41 for fixing a distal end part of the electrode part 21. The medical device is provided with a towing body 70 for urging the proximal end support part 31 toward a proximal end side relative to the distal end support part 41.SELECTED DRAWING: Figure 6

Description

The present invention relates to a medical device that is inserted into a living body and treats a living tissue by ablation.

As a medical device, a device that performs treatment by an irreversible electric drilling method (IRE) is known. The irreversible electrosurgical method is attracting attention because it is non-thermal and can suppress damage to surrounding blood vessels and nerves. For example, there is known a medical device that treats a cancer that is difficult to remove by surgery by using an irreversible electric perforation method.

A medical device that performs an irreversible electrosurgical method has a plurality of electrodes that can be expanded in the radial direction at the tip of a long shaft along the circumferential direction. In a medical device, electricity can be passed between the electrode portions while the electrode portions are in close contact with the biological tissue. Further, the shaft has an outer outer tube for fixing the base end portion of the electrode portion and an inner tube inserted into the lumen of the outer tube and fixing the tip end portion of the electrode portion. Since the outer tube and the inner tube are slidable with each other along the axial direction, the electrode portion can be expanded and contracted. Such a medical device includes, for example, those listed in Patent Document 1.

Japanese Patent No. 6013186

The expansion and contraction of the electrode portion in the living body is performed by the operator performing an operation of sliding the outer tube with respect to the inner tube. Therefore, the procedure is troublesome. In addition, a balloon may be used to expand the electrode portion, but the electrode portion can be expanded by expanding the balloon, but even if the balloon is contracted, it does not contract accordingly, so it depends on the operator. Operation is required.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a medical device capable of reducing the operational burden on the electrode portion.

A medical device according to the present invention that achieves the above object has a long shaft portion and an electrode portion arranged at the tip portion of the shaft portion and expandable in the radial direction, and the shaft portion is the electrode portion. It has a base end support portion for fixing the base end portion of the portion and a tip end support portion for fixing the tip end portion of the electrode portion, and the base end support portion is located on the proximal end side relative to the tip end support portion. A traction body was provided to urge them to face.

In the medical device configured as described above, since the proximal support portion of the electrode portion is urged toward the proximal end side by the traction body, when the expanding force is released with the electrode portion expanded, the traction body is released. The electrode portion can be automatically contracted by the urging force of the operator, and the operation burden on the operator can be reduced.

Further, the shaft portion has an outer pipe extending from the base end support portion to the hand portion, and an inner pipe inserted into the inner cavity of the outer pipe and having the tip support portion at the tip portion, and the outer pipe has the outer pipe. If the traction body is provided at the base end portion of the electrode portion, the electrode portion can be expanded by performing an operation of moving the outer pipe in the axial direction with respect to the inner pipe, and the operation of the outer pipe is stopped. As a result, the electrode portion can be automatically contracted by the urging force of the traction body.

Further, if the urging force of the traction body is smaller than the expansion force of the electrode portion and larger than the frictional force generated between the outer pipe and the inner pipe, the traction body does not hinder the expansion of the electrode portion and When the expanding force is released, the electrode portion can be reliably contracted by the urging force of the traction portion.

Further, if the outer tube has a handle portion for manually contracting the electrode portion, the electrode portion is contracted by operating the handle portion when the electrode portion cannot be contracted by the urging force of the traction body. Can be made to.

Further, if the outer tube has a lock portion that locks the movement of the outer tube in the axial direction with respect to the inner tube, the shaft portion can be locked in the expanded state of the electrode portion, and the expanded state of the electrode portion can be maintained. be able to.

Further, if a hole portion communicating with the lumen formed between the outer pipe and the inner pipe is provided on the base end side of the traction body, the space between the outer pipe and the inner pipe can be primed and primed. By flowing the fluid through the holes during the procedure, the fluid can be supplied from the proximal end side of the electrode portion, and the adhesion of blood clots to the electrode portion can be suppressed.

Further, if the traction body is made to generate an urging force by an elastic body, the traction body can be arranged in the medical device with a simple structure.

It is a front view which shows the outline of the medical device in this embodiment. It is an enlarged view of the vicinity of the tip portion of a medical device in a state where the electrode portion is expanded. It is an enlarged view of the vicinity of the operation handle part, and is the figure which showed the internal structure of the operation handle part. It is an enlarged view which looked at the internal structure of the operation handle part in the direction of the paper surface of FIG. It is sectional drawing which cut | cut the rotation prevention 1st member and the groove part by the plane orthogonal to the axial direction of a shaft part. It is an enlarged view of the vicinity of the operation handle part in the state which expanded the electrode part, and is the figure which showed the internal structure of the operation handle part. It is an enlarged cross-sectional view which cut in the vicinity of the handle member of the shaft part by the plane including the axis of the shaft part. It is sectional drawing which cut | cut the rotation prevention 1st member and the groove part in the modification of the twist prevention structure of a shaft part by the plane orthogonal to the axial direction of a shaft part. It is an enlarged view of the vicinity of the operation handle part in the modified example of the twist prevention structure of a shaft part, and is the figure which showed the internal structure of the operation handle part. It is an enlarged view of the vicinity of the operation handle part in the state which expanded the electrode part from the state of FIG. 9, and is the figure which showed the internal structure of the operation handle part. FIG. 5 is an enlarged cross-sectional view of the vicinity of the tip of the medical device of the first modification. It is the enlarged sectional view near the tip part of the medical device of the 1st modification in the state which expanded the balloon. It is an enlarged front view near the tip portion of the medical device of the 2nd modification. It is the enlarged front view near the tip part of the medical device of the 2nd modification in the state which expanded the balloon.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The dimensional ratios in the drawings may be exaggerated and differ from the actual ratios for convenience of explanation. Further, in the present specification, the side of the medical device 10 to be inserted into the living body cavity is referred to as "tip" or "tip side", and the hand side to be operated is referred to as "base end" or "base end side".

The medical device 10 of the present embodiment is inserted percutaneously into a living body cavity, comes into contact with a living body tissue at a target site, applies an electric current, and carries out an irreversible electric drilling method. The medical device 10 can also be used for high frequency ablation and electrochemotherapy.

As shown in FIG. 1, the medical device 10 has an expandable and contractible electrode portion 21 at the tip end portion of the long tubular shaft portion 20, and an operation handle portion 22 at the base end portion of the shaft portion 20. ing. The medical device 10 has a connecting line 12a for applying a voltage to the electrode portion 21 along the length direction. The connection line 12a is connected to a power supply unit 12 provided outside the medical device 10. The power supply unit 12 can apply a voltage to the electrode unit 21.

The shaft portion 20 has an outer tube 30 and an inner tube 40 arranged in the lumen thereof. A base end support portion 31 for fixing the base end portion of the electrode portion 21 is provided at the tip end portion of the outer tube 30. The base end support portion 31 is separate from the outer pipe 30 and is fixed to the tip end portion of the outer pipe 30. Further, the base end support portion 31 may be the tip end portion of the outer tube 30 to which the base end portion of the electrode portion 21 is directly fixed. Further, a tip support portion 41 for fixing the tip portion of the electrode portion 21 is formed at the tip portion of the inner tube 40. As the outer tube 30 moves relatively toward the tip side in the axial direction with respect to the inner tube 40, the electrode portion 21 expands in the radial direction as shown in FIG. On the other hand, as the outer tube 30 moves relatively toward the proximal end side in the axial direction with respect to the inner tube 40, the electrode portion 21 contracts in the radial direction.

Both the base end portion of the outer pipe 30 and the base end portion of the inner pipe 40 are housed in the operation handle portion 22. A handle member 80 having a handle portion 81 and a lock portion 82 is provided at the base end portion of the portion of the outer pipe 30 exposed from the operation handle portion 22. The handle member 80 will be described in detail later.

The outer tube 30 and the inner tube 40 are preferably formed of a material having a certain degree of flexibility. Examples of such a material include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof, and a soft polyvinyl chloride resin. Examples thereof include fluororesins such as polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane and polytetrafluoroethylene, silicone rubber and latex rubber.

The electrode portion 21 is a flexible linear member, and a plurality of electrode portions 21 are provided in the circumferential direction. In FIG. 1 and the like, for simplification, only two electrode portions 21 are shown, but in reality, a large number of electrode portions 21 are provided depending on the circumferential direction. The distance between the electrode portions 21 is preferably in the range of 3 to 10 mm, but may be other than this range. Further, the electrode portions 21 may be unevenly arranged in the circumferential direction.

The operation handle portion 22 has a housing portion 60 having a hollow inside. The base end side portion of the housing portion 60 is a grip portion 63 for the operator to hold and operate by hand.

As shown in FIG. 3, the rotation prevention first member 50 is fixed to the base end portion of the outer pipe 30 housed in the operation handle portion 22. The outer pipe 30 is fixed to the tip of the rotation prevention first member 50, and the tip of the towing body 70 formed of a tubular elastic body is fixed to the base end of the rotation prevention first member 50. ing. The traction body 70 has a connecting portion 71 at the base end portion, and is fixed to the outer peripheral surface of the inner pipe 40 by the connecting portion 71. Further, the flush tube 23 is pulled out from the connecting portion 71.

The inner pipe 40 arranged in the outer pipe 30 penetrates the inside of the rotation prevention first member 50, and the base end portion is fixed to the base end surface portion 61 of the operation handle portion 22.

The housing portion 60, which functions as the rotation prevention second member for preventing the rotation of the outer pipe 30 with respect to the inner pipe 40 together with the rotation prevention first member 50, has a groove portion 62 extending along the axial direction of the shaft portion 20. There is. The groove portion 62 holds the rotation prevention first member 50 so as not to rotate. The groove portion 62 is formed with support portions 62a for supporting the outer pipe 30 and the traction body 70 from below at a plurality of locations along the axial direction of the shaft portion 20.

The rotation prevention first member 50 and the housing portion 60 serving as the rotation prevention second member can be formed of hard plastic or metal.

As shown in FIG. 4, the rotation prevention first member 50 has a synchronous rotating portion 51 that can rotate together with the outer pipe 30. The tuning rotating portion 51 has protrusions 55 on the upper and lower sides, respectively, and is formed in a cross shape. The lower protrusion 55 is located in the groove 62. Further, the rotation prevention first member 50 has an outer pipe fixing portion 52 for fixing the outer pipe 30, a traction body fixing portion 53 for fixing the traction body 70, and a communication lumen 54 for inserting the inner pipe 40. There is.

The connecting portion 71 provided at the base end portion of the traction body 70 has an inner peripheral surface on the base end side fixed to the outer peripheral surface of the inner pipe 40. Further, the connecting portion 71 has a hole portion 72 that communicates with the lumen formed between the outer pipe 30 and the inner pipe 40. The hole portion 72 communicates with the flush tube 23 and is pulled out to the outside of the housing portion 60. Prime can be performed between the outer tube 30 and the inner tube 40 via the flash tube 23 and the hole 72. Further, during the procedure, the base end portion of the electrode portion 21 is fixed by flowing a fluid such as physiological saline between the outer tube 30 and the inner tube 40 via the flush tube 23 and the hole 72. It is possible to secure the flow of the fluid in the vicinity of the base end support portion 31. As a result, it is possible to prevent the thrombus from adhering to the electrode portion 21.

As shown in FIG. 5, the rotation prevention first member 50 has a non-circular cross-sectional shape orthogonal to the axial direction of the shaft portion 20 due to the protrusion 55. The groove portion 62 has both side walls close to both sides of the protrusion 55, and is a blocking surface 62b that prevents the rotation of the rotation prevention first member 50. The distance between the protrusion 55 and the blocking surface 62b is preferably 0.1 to 0.5 mm. Further, it is desirable that the protrusion 55 has a height of 0.75 to 1 times the groove width. However, as long as the rotation prevention first member 50 can move along the extending groove of the groove 62 and cannot rotate due to the blocking surface 62b, other intervals and heights may be used. ..

Due to the blocking surface 62b, the rotation prevention first member 50 cannot rotate with respect to the housing portion 60, which is the rotation prevention second member, along a plane orthogonal to the axial direction of the shaft portion 20. Since the outer pipe 30 is fixed to the rotation prevention first member 50, the inner pipe 40 and the housing portion 60, respectively, the rotation of the outer pipe 30 with respect to the inner pipe 40 is prevented, and the outer pipe 30 and the inner pipe 40 are connected to each other. It is possible to suppress the occurrence of twisting between them.

When the electrode portion 21 is expanded, as described above, the outer tube 30 moves relative to the inner tube 40 toward the tip end side. As shown in FIG. 6, when the outer tube 30 moves toward the tip end side, the rotation prevention first member 50 fixed to the base end portion of the outer tube 30 also moves toward the tip end side along the groove portion 62. .. In order to reduce the frictional force at this time, a lubricating coating or a lubricating oil may be applied to either or both of the rotation prevention first member 50 and the groove portion 62.

The protrusion 55 of the rotation prevention first member 50 is located on the most proximal side when the electrode portion 21 is most contracted, and is located on the most distal end side when the electrode portion 21 is most expanded. The groove portion 62 extends at least over a range in which the protrusion portion 55 moves along the axial direction of the shaft portion 20. That is, the groove portion 62 has a length obtained by adding the diameter of the protrusion portion 55 to at least the moving distance of the base end support portion 31 when expanding and contracting the electrode portion 21. As a result, twisting of the outer tube 30 and the inner tube 40 can be suppressed at both the contraction and expansion of the electrode portion 21.

When the protrusion 55 of the rotation prevention first member 50 further moves toward the tip end side, it comes into contact with the support portion 62a formed in the groove portion 62. The support portion 62a regulates the rotation prevention first member 50 and the outer pipe 30 so that they cannot move further to the tip side. As a result, overexpansion of the electrode portion 21 can be prevented. That is, the support portion 62a also functions as a stopper portion that regulates the axial movement of the rotation prevention first member 50.

When the outer tube 30 moves toward the tip end side, the traction body 70 formed of the tubular elastic body extends along the axial direction of the shaft portion 20. The extended traction body 70 urges the proximal end support portion 31 of the electrode portion 21 via the outer tube 30 so as to be relative to the distal end support portion 41 toward the proximal end side. Therefore, when the force for moving the outer tube 30 toward the tip end side is lost or weakened, the traction body 70 moves the proximal end support portion 31 toward the proximal end side with respect to the distal end support portion 41 and contracts the electrode portion 21. Let me.

The traction body 70 is attached so as to generate an urging force when the electrode portion 21 contracts, and constantly urges the proximal end support portion 31 of the electrode portion 21 via the outer tube 30. The urging force is smaller than the force that expands the electrode portion 21, and is larger than the frictional force generated between the outer tube 30 and the inner tube 40. As a result, the operator can operate the electrode portion 21 to expand by moving the outer tube 30 toward the tip side against the urging force of the traction body 70. On the other hand, when the operator weakens or eliminates the force against the urging force of the traction body 70, the traction body 70 moves the proximal end support portion 31 toward the proximal end side, and the electrode portion 21 automatically contracts. To do. As a result, it is not necessary for the operator to perform an operation for contracting the electrode portion 21, and the operability of the medical device 10 can be improved.

The traction body 70, which is a tubular elastic body, can be formed of silicone rubber, synthetic rubber, styrene elastomer, nylon elastomer, or the like. Further, the traction body 70 does not necessarily have to be tubular, and may be, for example, a spring. When the traction body 70 is composed of a spring, stainless steel, copper, plastic or the like can be used as the material. Further, as the traction body 70, an elastic thread made of rubber or an elastomer may be used.

Since the handle member 80 is fixed to the outer peripheral surface of the outer pipe 30, it moves with the movement of the outer pipe 30 in the axial direction. Since the handle member 80 has a handle portion 81 projecting in the radial direction of the shaft portion 20, the operator manually moves the outer pipe 30 to the proximal end side by the traction body 70. Can be used to move the outer tube 30 in. Therefore, it is desirable that the handle portion 81 has a length of 2 cm or more. As the material of the handle member 80, a hard plastic having good adhesiveness to the shaft portion 20 is desirable, and for example, polyphenylene sulfide resin (PPS), polycarbonate, or the like can be used.

As shown in FIG. 7, the lock portion 82 is a screw member inserted into the through hole 81a formed in the handle portion 81. By rotating the lock portion 82, the lock portion 82 enters the inner side of the through hole 81a and presses against the outer pipe 30. The outer tube 30 is pressed against the inner tube 40 by the lock portion 82, whereby the outer tube 30 becomes immovable in the axial direction with respect to the inner tube 40 and is locked so that the expanded state of the electrode portion 21 does not change. Can be done.

Although the lock portion 82 is provided on the handle member 80 in the present embodiment, the lock portion 82 may be provided on a place other than the handle member 80. Further, the lock portion 82 may be a member other than the screw member as long as the movement of the outer pipe 30 and the inner pipe 40 in the axial direction can be regulated. For example, a valve body is provided in the lumen of the outer tube 30 to insert the inner tube 40, a tapered tapered surface is provided on the tip side of the valve body, and the valve body is moved to the tip side on the base end side of the valve body. A pressing member to be provided may be provided, and this may be used as a lock portion. In this case, by operating the pressing member so as to move it to the tip side, the valve body is pressed against the tapered surface and compressed, and the inner tube 40 can be made immovable in the axial direction by the compressive force.

Next, a modified example of the traction body will be described. In this example, a magnet is used as the traction body. As shown in FIG. 8, the traction body 75 has a first magnet portion 76 and a second magnet portion 77. The first magnet portion 76 is provided on the side surface of the base end of the rotation prevention first member 50. Further, the second magnet portion 77 is located on the proximal end side of the rotation prevention first member 50 and is fixed to the outer peripheral surface of the inner pipe 40. The first magnet portion 76 and the second magnet portion 77 are arranged so that different poles face each other.

The first magnet portion 76 connected to the outer tube 30 is urged so as to be constantly pulled by the second magnet portion 77 connected to the inner tube 40. As shown in FIG. 9, in the state where the electrode portion 21 is contracted, the first magnet portion 76 and the second magnet portion 77 constituting the traction body 75 are separated from each other. As shown in FIG. 10, in the expanded state of the electrode portion 21, the first magnet portion 76 and the second magnet portion 77 constituting the traction body 75 are separated from each other more than in FIG. The urging force by the traction body 75 in FIG. 10 is smaller than the force for expanding the electrode portion 21, and is larger than the frictional force generated between the outer tube 30 and the inner tube 40. As a result, the electrode portion 21 can be automatically contracted.

Next, the medical device 100 according to the modified example using the balloon will be described. As shown in FIG. 11, the medical device 100 has a balloon 104 and an electrode portion 105 at the tip of a shaft portion 101 having an outer tube 102 and an inner tube 103. The inner pipe 103 has a double pipe structure in which the inner first pipe 110 and the outer second pipe 111 are arranged concentrically. A guide wire lumen 112 through which a guide wire is inserted is formed inside the hollow of the first tube body 110. Further, an expansion lumen 113 for circulating the expansion fluid of the balloon 104 is formed inside the hollow of the second tube body 111 and outside the first tube body 110.

The first tubular body 110 projects further to the distal end side than the distal end of the second tubular body 111. The base end side end of the balloon 104 is fixed to the second tube body 111, and the tip end side end portion is fixed to the first tube body 110. As a result, the inside of the balloon 104 communicates with the expansion lumen 113. The balloon 104 can be expanded by injecting an expansion fluid into the balloon 104 via the expansion lumen 113. The expansion fluid may be a gas or a liquid, and for example, a gas such as helium gas, CO ₂ gas, O ₂ gas, or laughing gas, or a liquid such as physiological saline, a contrast medium, or a mixture thereof can be used.

A base end support portion 115 is provided at the tip end portion of the outer tube 102, and a tip end support portion 116 is provided at the tip end portion of the inner tube 103. The base end support portion 115 has a plurality of fixing holes 115a in the circumferential direction in order to fix the base end portion of the electrode portion 105. The number of fixing holes 115a corresponds to the number of electrode portions 105, and the fixing holes 115a are evenly arranged in the circumferential direction of the proximal end support portion 115. The tip support portion 116 has a plurality of accommodating portions 116a in the circumferential direction in order to fix the tip portion of the electrode portion 105. The number of accommodating portions 116a matches the number of electrode portions 105, and the accommodating portions 116a are evenly arranged in the circumferential direction of the tip support portion 116.

In this modification, the structure of the operation handle portion 22 is as described above. Further, when the electrode portion 105 is expanded by the balloon 104, the locked portion 82 is unnecessary because the expanded state of the electrode 105 can be maintained while the balloon 104 is expanded.

The connecting line 118 is spirally wound and embedded in the first pipe body 110 of the inner pipe 103. The connection line 118 is pulled out from the tip of the first tubular body 110 into the tip support portion 116, and is connected to the tip of the electrode portion 105 arranged in the accommodating portion 116a.

In the electrode portion 105, the balloon joint portion 105a on the distal end side is bonded to the surface of the balloon 104 by adhesion.

When the balloon 104 expands, the electrode portion 105 expands in the radial direction as shown in FIG. Of the electrode portions 105, the balloon joint portion 105a is bonded to the balloon 104 by adhesion as described above, and therefore is supported by the balloon 104 to increase the diameter from the tip end to the base end. The vicinity of the maximum diameter portion of the balloon 104 is supported by the balloon 104 and comes into close contact with the living tissue. The portion of the electrode portion 105 on the proximal end side of the maximum diameter portion of the balloon 104 is reduced in diameter from the tip to the proximal end without contacting the balloon 104. When the balloon 104 is expanded and the electrode portion 105 is expanded, the proximal end support portion 115 moves so as to approach the tip end support portion 116. Along with this, the outer pipe 102 also moves toward the tip side relative to the inner pipe 103. The urging force of the traction body 70 connected to the base end portion of the outer tube 102 is set to be smaller than the expanding force of the balloon 104. Thereby, the traction body 70 can be prevented from hindering the expansion of the electrode portion 105 by the balloon 104.

When the balloon 104 is contracted, the proximal end support portion 115 of the electrode portion 105 moves toward the proximal end side by the urging force of the traction body 70. As a result, the electrode portion 105 contracts in the radial direction. In this way, when the electrode portion 105 is expanded by the balloon 104, the electrode portion 105 can be contracted following the contraction of the balloon 104 by the urging force of the traction body 70, and the operation burden on the operator can be reduced. ..

Further, since the electrode portion 105 is joined to the balloon 104 at the balloon joint portion 105a, if the electrode portion 105 cannot be contracted when the balloon 104 contracts, the balloon 104 contracts incompletely. In this example, since the electrode portion 105 can be contracted following the contraction of the balloon 104 by the traction body 70, incomplete contraction of the balloon 104 can be prevented.

Next, the medical device 120 according to the second modification using the balloon will be described. As shown in FIG. 13, the outer pipe is not provided in this modified example. The traction body 121 is directly connected to the proximal end side of the proximal end support portion 115 of the electrode portion 105. A connecting portion 122 is provided at the base end portion of the traction body 121 and is connected to the inner pipe 103.

As shown in FIG. 14, when the base end support portion 115 moves closer to the tip end support portion 116 due to the expansion of the electrode portion 105 accompanying the expansion of the balloon 104, the traction body whose base end portion is fixed to the inner tube 103. 121 extends and urges the proximal support 115 toward the proximal side. Due to this urging force, when the balloon 104 contracts, the proximal support portion 115 can be moved toward the proximal end side, and the electrode portion 105 can be contracted in the radial direction. As described above, in this modification, the electrode portion 105 can be expanded by the balloon 104 and the electrode portion 105 can be contracted by the traction body 121 without providing the outer tube.

As described above, the medical device 10 according to the present embodiment has a long shaft portion 20 and an electrode portion 21 arranged at the tip portion of the shaft portion 20 and expandable in the radial direction, and the shaft portion 20. Has a base end support portion 31 for fixing the base end portion of the electrode portion 21 and a tip end support portion 41 for fixing the tip end portion of the electrode portion 21, and the base end support portion 31 is relative to the tip end support portion 41. A traction body 70 is provided so as to be biased toward the base end side. In the medical device 10 configured in this way, since the proximal support portion 31 of the electrode portion 21 is urged toward the proximal end side by the traction body 70, the expanding force is released in the expanded state of the electrode portion 21. Then, the electrode portion 21 can be automatically contracted by the urging force of the traction body 70, and the operation burden on the operator can be reduced.

Further, the shaft portion 20 has an outer pipe 30 extending from the base end support portion 31 to the hand portion, and an inner pipe 40 inserted into the inner cavity of the outer pipe 30 and having the tip support portion 41 at the tip portion. If the traction body 70 is provided at the base end portion of the pipe 30, the electrode portion 21 can be expanded by performing an operation of moving the outer pipe 30 in the axial direction with respect to the inner pipe 40, and the outer pipe 30 can be expanded. By stopping the operation of the tube 30, the electrode portion 21 can be automatically contracted by the urging force of the traction body 70.

Further, if the urging force of the traction body 70 is smaller than the expansion force of the electrode portion 21 and larger than the frictional force generated between the outer pipe 30 and the inner pipe 40, the traction body 70 hinders the expansion of the electrode portion 21. Moreover, when the expanding force is released, the electrode portion 21 can be reliably contracted by the urging force of the traction portion 70.

Further, if the outer tube 30 has a handle portion 81 that manually contracts the electrode portion 21, the handle portion 81 can be operated when the electrode portion 21 cannot be contracted by the urging force of the traction body 70. The electrode portion 21 can be contracted.

Further, if the lock portion 82 that locks the axial movement of the outer pipe 30 with respect to the inner pipe 40 is provided, the shaft portion 20 is locked with the electrode portion 21 expanded, and the expanded state of the electrode portion 21 is changed. It can be maintained.

Further, if a hole 72 that communicates with the lumen formed between the outer pipe 30 and the inner pipe 40 is provided on the base end side of the traction body 70, the space between the outer pipe 30 and the inner pipe 40 can be provided. By priming and allowing the fluid to flow through the hole 72 during the procedure, the fluid can be supplied from the proximal end side of the electrode portion 21 and the adhesion of blood clots to the electrode portion 21 can be suppressed.

Further, if the traction body 70 is made to generate an urging force by an elastic body, the traction body 70 can be arranged on the medical device 10 with a simple structure.

The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical idea of the present invention. In the above-described embodiment, the hole 72 communicating with the lumen between the outer pipe 30 and the inner pipe 40 is provided, but the hole 72 is provided as needed, and even if it is not provided. Good.

10 Medical device 12 Power supply part 20 Shaft part 21 Electrode part 22 Operation handle part 30 Outer pipe 31 Base end support part 40 Inner pipe 41 Tip support part 50 Anti-rotation first member 51 Synchronized rotating part 52 Outer pipe fixing part 53 Traction body fixing Part 54 Communication lumen 55 Protrusion part 60 Housing part 61 Base end surface part 62 Groove part 62a Support part 62b Blocking surface 63 Grip part 70 Pulling body 71 Connecting part 72 Hole part 80 Handle member 81 Handle part 81a Through hole 82 Lock part

Claims (7)

With a long shaft
It has an electrode portion arranged at the tip portion of the shaft portion and expandable in the radial direction.
The shaft portion has a base end support portion for fixing the base end portion of the electrode portion and a tip support portion for fixing the tip end portion of the electrode portion.
A medical device provided with a traction body that urges the proximal end support portion so as to be relative to the distal end support portion toward the proximal end side. The shaft portion has an outer pipe extending from the base end support portion to the hand portion, and an inner pipe inserted into the lumen of the outer pipe and having the tip support portion at the tip portion.
The medical device according to claim 1, wherein the traction body is provided at a base end portion of the outer tube. The medical device according to claim 2, wherein the urging force of the traction body is smaller than the expanding force of the electrode portion and larger than the frictional force generated between the outer tube and the inner tube. The medical device according to claim 2 or 3, wherein the outer tube has a handle portion for manually contracting the electrode portion. The medical device according to any one of claims 2 to 4, further comprising a locking portion that locks the axial movement of the outer tube with respect to the inner tube. The medical device according to any one of claims 2 to 5, wherein a hole communicating with a lumen formed between the outer tube and the inner tube is provided on the proximal end side of the traction body. The medical device according to any one of claims 1 to 6, wherein the traction body generates an urging force by an elastic body.

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