JP7245682B2 - medical device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a medical device for placing a medical treatment tool in a biological lumen.

Conventionally, as an example of a medical treatment device, it is indwelled in a constriction or obstruction occurring in a biological lumen such as a blood vessel, esophagus, bile duct, trachea, or ureter, and expands the diameter of the lesion site to keep the biological lumen open. Stents that maintain A stent has, for example, a skeleton formed by weaving wires into a tubular shape, and can be expanded and contracted in the radial direction by deformation of the mesh. As another example of a medical treatment device, a so-called stent graft is known, in which a membrane portion such as an artificial blood vessel (graft) is formed on a skeleton portion made of a stent.

In general, a medical device for indwelling a medical treatment tool such as a stent in a biological lumen includes a sheath, a tubular member inserted through the sheath, and an operation section for moving the tubular member and the sheath relative to each other in the axial direction. It has (for example, patent document 1). Patent Literature 1 discloses a stent graft placement system for placing a stent graft in a blood vessel as an example of a medical device. The medical treatment instrument is arranged at the distal end of the tubular member and accommodated in the sheath in a contracted state.

The tubular member in which the medical treatment instrument is arranged is introduced into the living body lumen together with the sheath and transported to the lesion site. After adjusting the indwelling position of the medical treatment instrument, for example, by moving the sheath to the proximal side, the medical treatment instrument is exposed from the sheath and released into the biological lumen.

The medical device disclosed in Patent Literature 1 has a feed screw mechanism in the operation portion. Specifically, a male thread is provided on the outer peripheral surface of a cylindrical fixing part to which the sheath is fixed, a female thread is provided on the inner peripheral surface of a cylindrical handle arranged outside the fixing part, and the male and female threads are screwed together. A lead screw mechanism is formed by bringing them together. As the handle rotates about its axis, the feed screw moves the sheath proximally, thereby gradually releasing the medical treatment instrument.

Japanese Patent No. 5846505

However, in the medical device disclosed in Patent Document 1, since the male thread of the fixing portion is exposed to the outside, for example, blood scattered during surgery adheres to the medical device, resulting in deterioration of operability when the medical treatment instrument is indwelled. There is a possibility that the efficiency of placing the medical treatment instrument may be lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a medical device capable of efficiently placing a medical treatment tool in a living body lumen.

The medical device according to the present invention comprises
A medical device for placing a medical treatment instrument in a biological lumen,
a sheath;
a tubular member having a medical treatment instrument disposed at its distal end and inserted through the sheath;
an operation unit provided on the rear end side of the sheath and the tubular member and configured to move the sheath and the tubular member relative to each other in an axial direction;
The operation unit is
a fixing part that fixes the sheath or the tubular member;
a moving mechanism for moving the fixed portion in the axial direction;
a cover that accommodates the fixing part;
The moving mechanism is
a rack provided inside the cover along the axial direction;
a gear train including a first gear supported by the fixed portion and meshing with the rack;
a handle for operating the gear train;
When the first gear rotates with the operation of the handle, the fixing portion axially moves along the rack, and at least one of the sheath and the tubular member axially moves relative to each other. The medical treatment instrument is characterized in that it is discharged into the living body lumen.

ADVANTAGE OF THE INVENTION According to this invention, a medical treatment instrument can be efficiently indwelled in a biological lumen.

FIG. 1 is a perspective view showing the overall configuration of a stent graft placement system according to an embodiment. FIG. 2 is a cross-sectional view showing the configuration of the blood vessel introduction portion in the stent graft placement system. 3A and 3B are perspective views showing the configuration of the operating section. FIG. 4 is a perspective view showing the internal configuration of the operating section. FIG. 5 is an exploded perspective view of the distal portion of the manipulator; FIG. 6 is a cross-sectional view of the distal portion of the operating portion; FIG. 7 is an exploded perspective view of the gearbox, trigger and gear train;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, as an example of a medical device according to the present invention, a stent graft placement system 1 for placing a stent graft 14, which is a medical treatment tool, in a lesion site of a blood vessel (for example, a stenotic or occluded portion of a blood vessel) will be described. .

FIG. 1 is a perspective view showing the overall configuration of a stent graft placement system 1 according to an embodiment. FIG. 2 is a cross-sectional view showing the configuration of the catheter section 10 in the stent graft placement system 1. As shown in FIG.
As shown in FIGS. 1 and 2, the stent graft placement system 1 includes a catheter section 10 and an operating section 20. As shown in FIGS.

Catheter section 10 has sheath 11 , tubular member 12 , inner rod 13 and stent graft 14 . The sheath 11 , the tubular member 12 and the inner rod 13 each have a tubular shape.

The stent graft 14 is a tubular intravascular indwelling device (an example of a medical treatment device) having a membrane portion and a skeleton portion (both not shown). The membrane portion is sewn and fixed to the outer peripheral surface of the skeleton portion, for example, with a suture thread. The skeleton portion is, for example, a self-expanding stent skeleton formed in a tubular shape along the peripheral surface of the coating portion while a thin metal wire is zigzag-folded in the axial direction. The skeletal portion is configured to be deformable from a contracted state in which it contracts radially inwardly to an expanded state in which it expands radially outwardly to define a tubular flow path.

The inner rod 13 has a distal tip 13a at its distal end. A stent graft 14 is positioned at the distal end of tubular member 12 . The end of the skeleton of the stent graft 14 is connected to a cradle (not shown) provided on the proximal side of the distal tip 13a. The tubular member 12 is inserted through the sheath 11 with the stent graft 14 contracted (folded).

The sheath 11 is made of a flexible material. Examples of flexible materials include biocompatible synthetic resins (elastomers) selected from fluorine resins, polyamide resins, polyethylene resins, and polyvinyl chloride resins, and other materials besides these resins. , a multilayer structure made of these synthetic resins, and composites of these synthetic resins and metal wires.

Examples of materials that constitute the tubular member 12 and the inner rod 13 include various materials having appropriate hardness and flexibility, such as resins (plastics, elastomers) and metals. As the material constituting the tip 13a, various materials having appropriate hardness and flexibility, such as synthetic resins (elastomers) selected from polyamide resins, polyurethane resins, polyvinyl chloride resins, etc., can be used. is mentioned.

The operating section 20 is provided on the proximal end (rear end) side of the catheter section 10 . The operation unit 20 has a sheath fixing part (corresponding to the fixing part in the present invention) that fixes the sheath, a movement mechanism that moves the sheath fixing part in the axial direction, and covers 21 and 22 that accommodate the sheath fixing part. . The operation part 20 is used when the sheath 11 and the tubular member 12 are relatively moved in the axial direction, and when the tubular member 12 and the inner rod 13 are relatively moved in the axial direction. In this embodiment, the sheath fixing section includes gear box 25 and the like, and the moving mechanism includes gear train 27, rack 28, front handle 23 and the like.

A guide wire 30 (see FIG. 2) previously introduced into the blood vessel is inserted through the lumen of the inner rod 13, and the catheter section 10 is advanced along the guide wire 30, so that the distal end of the catheter section 10 reaches the lesion site. be transported. In this embodiment, the operation part 20 (the front handle 23 and the button 263) is operated so that the state shown in FIG. 3A changes to the state shown in FIG. hand side), the stent graft 14 is released from the sheath 11, expanded by the self-expanding force of the skeletal portion, and left in the blood vessel. 3B, the operating portion 20 (rear handle 24) is operated to axially move the tubular member 12 with respect to the inner rod 13, thereby engaging the stent graft 14 and the cradle (not shown). The condition is released and the distal end of stent graft 14 is released.

The configuration of the operation unit 20 will be described in detail below. 3A and 3B are perspective views showing the configuration of the operating section 20. FIG. FIG. 3A shows the state before the stent graft 14 is deployed, and FIG. 3B shows the state after the stent graft 14 is deployed. FIG. 4 is a perspective view showing the internal configuration of the operating section 20. As shown in FIG. FIG. 4 shows the state of the operation unit 20 with the front cover 21, the upper cover 221, the front handle 23 and the rear handle 24 removed. FIG. 5 is an exploded perspective view of the distal portion of the operating portion 20. FIG. FIG. 6 is a cross-sectional view of the distal portion of the operating portion 20. FIG. 7 is an exploded perspective view of the gearbox 25, trigger 26 and gear train 27. FIG.

As shown in FIGS. 3A, 3B, and 4 to 7, the operation unit 20 includes a front cover 21, a cover body 22, a front handle 23, a rear handle 24, a gear box 25, a trigger 26, a gear train 27, and a rack 28. , and rod guide shafts 29 and the like.

The front cover 21 has a hollow semi-fusiform shape and is attached to the distal side of the cover body 22 . The front cover 21 has an opening 21a for inserting the catheter section 10 at its distal end.

The cover body 22 has a cylindrical shape. In this embodiment, the cover main body 22 has a divided structure consisting of a semi-cylindrical upper cover 221 and a lower cover 222 . The cover main body 22 accommodates therein a gear box 25, a trigger 26, a gear train 27, a rack 28, and the like.

The upper cover 221 has an oval slit 221a along the axial direction. A second gear 272 of the gear train 27 protrudes outside from the slit 221 a and meshes with the worm 23 a of the front handle 23 . A button 263 of the trigger 26 protrudes outside from the slit 221a and can be operated by the operator. The axial length of the slit 221a is set longer than the movable length of the gearbox 25 (sheath fixing portion).

The racks 28 are arranged on the inner peripheral surface of the upper cover 221 along both peripheral edges along the axial direction of the slit 221a. In this embodiment, rack 28 is formed integrally with upper cover 221 . The axial length of the rack 28 corresponds to the movable length of the gearbox 25 (sheath fixing portion).

The front handle 23 has a cylindrical shape and is fitted on the outer peripheral surface of the cover body 22 . The front handle 23 has a worm 23a (screw gear) on its inner peripheral surface. The worm 23 a meshes with the second gear 272 of the gear train 27 . In addition, an engagement groove 23b that engages with a stopper 257, which will be described later, is provided along the circumferential direction on the inner peripheral surface of the front handle 23 and at a position on the proximal side of the worm 23a. The engagement groove 23b is a groove of a predetermined depth provided from the inner peripheral surface of the front handle 23 toward the outer surface thereof. A portion of the engagement groove 23b opens to the outer surface of the front handle 23. As shown in FIG.

The rod guide shaft 29 has a cylindrical shape, and a fixed terminal (not shown) for fixing the proximal end of the tubular member 12 is arranged inside the rod guide shaft 29 . A rod guide shaft 29 is fixed to the cover body 22 . A fixed terminal arranged on the rod guide shaft 29 constitutes a feed screw mechanism together with the rear handle 24 .

When the rear handle 24 is rotated about its axis, a fixed terminal (not shown) is axially moved along the slit of the rod guide shaft 29 by a feed screw mechanism. Thereby, the tubular member 12 fixed to the fixed terminal advances and retreats along the inner rod 13 in the axial direction. Specifically, as will be described later, for example, after the front handle 23 is moved proximally (hand side) to release the stent graft 14, the rear handle 24 is rotated in one direction (for example, clockwise) around the axis. , the tubular member 12 is moved proximally with respect to the inner rod 13 . As a result, the stent graft 14 is disengaged from the cradle (not shown), and the distal end of the stent graft 14 is released.

The gearbox 25 has a sheath connection portion 251 , a rod insertion portion 252 , a spring holding portion 253 , a gear accommodation portion 254 , a regulation portion 256 and a stopper 257 . In this embodiment, the gearbox 25 constitutes a part of the sheath fixing portion that fixes the sheath 11 .

The sheath connection part 251 has a cylindrical shape and fixes the proximal end of the sheath 11 . In this embodiment, the sheath connection portion 251 is provided at the distal end portion of the gearbox 25 .

The rod insertion portion 252 is provided on the proximal end side of the sheath connection portion 251 . The tubular member 12 and the inner rod 13 exposed from the proximal end of the sheath 11 are inserted through the rod insertion portion 252 .

The spring holding portion 253 holds the first spring 31 . The spring holding portion 253 has a convex portion 253a protruding upward.

The gear housing portion 254 houses the gear train 27 .

The spring holding portion 253 and the gear housing portion 254 are open at the top. The spring and gear housing portion 254 is formed by two side plates 255 along the axial direction. The side plates 255, 255 each have a through hole 255a, a bearing hole 255b, a trigger connecting portion 255c, and a locking portion 255e. One side plate 255 (the side plate 255 on the front side in FIG. 6) has a spring mounting portion 255d.

The through hole 255a is an oblong hole extending obliquely downward toward the proximal side. The first gear shaft 274 is inserted through the through hole 255a. The bearing hole 255b supports the second gear shaft 275. As shown in FIG. The trigger connection portion 255c is engaged with the engagement hole 261b of the trigger 261. As shown in FIG. One end of the second spring 32 is connected to the spring mounting portion 255d. The second spring 32 is composed of, for example, a compression coil spring. The locking portion 255e locks the locking piece 261c of the trigger 26. As shown in FIG.

The restricting portion 256 is provided along the axial direction at the center in the width direction on the distal side of the spring holding portion 253 . The restricting portion 256 is positioned below the connecting portion 262 of the trigger 26 and restricts the button 263 from being pushed downward.

The stopper 257 is a screw-like member provided on the proximal side of the gear housing portion 254 and facing upward. The stopper 257 is attached to a screw hole (reference numerals omitted) of the gear box 25 via an opening connected to the engagement groove 23b of the front handle 23, and is configured to be able to adjust the upper surface position by using a jig. As shown in FIG. 6, by setting the upper surface position of the stopper 257 to be higher than the inner peripheral surface of the front handle 23, the front handle 23 and the front handle 23 are prevented from falling off from the worm. The gearbox 25 can be moved integrally along the axial direction.

The trigger 26 has two side plates 261, 261 along the axial direction. Side plates 261 , 261 are connected at a connecting portion 262 on the distal side. A button 263 is arranged on the connecting portion 262 .

The side plates 261, 261 each have a bearing hole 261a, an engaging hole 261b, a locking piece 261c and a spring mounting portion 261d.
The bearing hole 261a and the engaging hole 261b have an oval shape along the axial direction. The first gear shaft 274 is inserted through the bearing hole 261a. The trigger connection portion 255c of the gearbox 25 is engaged with the engagement hole 261b. The locking piece 261 c is locked to the locking portion 255 e of the gearbox 25 . The other end of the second spring 32 is connected to the spring mounting portion 261d.

The button 263 has a protrusion 263a protruding downward. The first spring 31 is mounted between the convex portion 253 a of the spring holding portion 253 and the convex portion 263 a of the button 263 . The first spring 31 is composed of, for example, a compression coil spring.

The trigger 26 is attached to the gear box 25 while being biased obliquely upward by the first spring 31 . At this time, the side plate 261 of the trigger 26 is positioned outside the side plate 255 of the gearbox 25, and the locking piece 261c is positioned below the locking portion 255e. The trigger connection portion 255c of the gearbox 25 is inserted into the engagement hole 261b of the trigger 26, and the locking piece 261c of the trigger 26 is locked to the locking portion 255e of the gearbox 25, thereby connecting the gearbox 25 and the trigger. 26 are integrated and held in a biased state.

That is, in the present embodiment, the sheath fixing portion includes the trigger 26 (first member) that supports the first gear 271, the gearbox 25 (second member) that supports the second gear 272, the trigger 26 and the gear. a first spring 31 (biasing member) interposed between the box 25 and biasing the trigger 26 in the direction in which the first gear 271 meshes with the rack 28 to maintain the meshing state. there is In addition, in the present embodiment, the gear box 25 (second member) supports the first gear 271 as well as the second gear 272 .

The gear train 27 has a first gear 271 , a second gear 272 and a third gear 273 . The first gear 271 is a pinion gear that meshes with the rack 28 . In this embodiment, two first gears 271 are provided with a third gear 273 interposed therebetween. The second gear 272 is a worm wheel that meshes with the worm 23 a of the front handle 23 . The third gear 273 is a relay gear that transmits rotation of the second gear 272 to the first gear 271 . The third gear 273 is fixed to the same first gear shaft 274 as the first gear 271 .

A first gear shaft 274 to which the first gear 271 and the third gear 273 are fixed is inserted through the through hole 255a of the gearbox 25 and into the bearing hole 261a of the trigger 26 . A second gear shaft 275 to which the second gear 272 is fixed is inserted through the bearing hole 255 b of the gear box 25 .

In the operation unit 20, when the front handle 23 is rotated around the axis, the second gear 272 rotates via the worm 23a. Rotation of the second gear 272 is transmitted to the first gear 271 via the third gear 273 . The rotation of the first gear 271 is converted by the rack 28 into linear motion along the axial direction. Since the rack 28 is fixed to the cover body 22, the gearbox 25 with the gear train 27 moves axially.

The sheath 11 is fixed to the gearbox 25, and the tubular member 12 is fixed to a fixed terminal (not shown) of the rod guide shaft 29 integrated with the cover body 22. 11 will move axially. As a result, the stent graft 14 placed on the tubular member 12 can be gradually exposed and released from the sheath 11, and the indwelling position of the stent graft 14 can be finely adjusted.

Further, in the present embodiment, the rack 28 and the first gear 271 are configured to be switchable between the engaged state and the separated state. Specifically, when the button 263 of the trigger 26 is pressed, the trigger 26 rotates downward about the trigger connecting portion 255c of the gearbox 25, and the first gear 271 moves downward together with the trigger 26. As a result, the first gear 271 and the rack 28 are separated from each other. At this time, the first gear shaft 274 to which the first gear 271 is fixed moves along the oblong through-hole 255 a provided in the gear box 25 . On the other hand, the engaged state between the front handle 23 and the second gear 272 and the engaged state between the second gear 272 and the third gear 273 are maintained.

Therefore, the gear box 25, the trigger 26, the gear train 27 and the front handle 23 are axially movable with respect to the cover body 22 on which the rack 28 is arranged. As a result, after finely adjusting the indwelling position of the stent graft 14, the stent graft 14 can be released at once by pressing the button 263 and sliding it to the proximal side. When the button 263 is released, the restoring force of the first spring 31 and the second spring 32 restores the trigger 26 to its original state, and the rack 28 and the first gear 271 are engaged.

Further, in the present embodiment, the gearbox 25 (second member) has a restricting portion 256 that restricts the trigger 26 from being pushed against the biasing force of the first spring 31 (biasing member). there is On the other hand, the trigger 26 is configured to be axially movable with respect to the gearbox 25 . Specifically, the trigger 26 is connected to the gearbox 25 by engagement between the oval bearing hole 261a and the first gear shaft 274 and engagement between the oval engagement hole 261b and the trigger connecting portion 255c. Concatenated.

Therefore, only when the button 263 of the trigger 26 is moved to the proximal side, the regulation by the regulation portion 256 is released and the trigger 26 can be pushed. As a result, it is possible to prevent the rack 28 and the first gear 271 from being disengaged due to an erroneous operation.

As described above, the stent graft placement system 1 (medical device) according to the present embodiment is a medical device for placing the stent graft 14 (medical treatment instrument) in a blood vessel (biological lumen). a tubular member 12 inserted through the sheath 11 in the contracted state of the stent graft 14; and an operation unit 20 for moving in a direction. The operation unit 20 has a gearbox 25 (fixed portion) that fixes the sheath, a moving mechanism that moves the gearbox 25 in the axial direction, and a cover body 22 (cover) that accommodates the gearbox 25 .
The movement mechanism operates a rack 28 provided inside the cover body 22 along the axial direction, a gear train 27 including a first gear 271 supported by the gear box 25 and engaged with the rack 28, and the gear train 27. and a front handle 23 (handle). As the first gear 271 rotates as the front handle 23 is operated, the gear box 25 moves axially along the rack 28 to move the sheath 11 proximally with respect to the tubular member 12 . The stent graft 14 is released from the.

According to the stent graft placement system 1 , the front handle 23 is operated to operate the movement mechanism consisting of the rack and pinion arranged within the cover body 22 to move the sheath 11 with respect to the tubular member 12 . Fine adjustment of the indwelling position can be performed while gradually releasing the Further, since the rack-and-pinion mechanism is enclosed in the cover body 22, operability is not deteriorated due to adherence of blood that scatters during surgery. Therefore, according to the stent graft placement system 1, the stent graft 14 can be efficiently placed in the blood vessel.

Further, the rack 28 and the first gear 271 are configured to be switchable between an engaged state and a separated state. It can move freely in any direction. Therefore, by operating the front handle 23, the gear box 25 can be moved proximally in the axial direction, and the stent graft 14 whose indwelling position has been finely adjusted can be released at once.

Furthermore, by operating the rear handle 24 to move the tubular member 12 proximally with respect to the inner rod 13, the engagement between the stent graft 14 and the cradle (not shown) is released and the distal end portion of the stent graft 14 is released. can be released, the stent graft 14 can be placed efficiently. That is, since the rear handle 24 for opening the distal end portion of the stent graft 14 is provided in the vicinity of the front handle 23 moved proximally to release the stent graft 14 at once (see FIG. 3B), operation The operator's hand can be immediately moved from the front handle 23 to the rear handle 24, and the operator can intuitively perform the placement operation of the stent graft 14.例文帳に追加

Although the invention made by the inventor of the present invention has been specifically described above based on the embodiments, the present invention is not limited to the above embodiments, and can be changed without departing from the scope of the invention.

For example, the present invention can be applied not only to the stent graft 14 described in the embodiment, but also to a medical device for placing a stent in a biological lumen such as a digestive system lumen. In addition to stent grafts, medical treatment instruments that are indwelled by medical devices include anti-adhesion materials and thrombectomy devices (see Japanese Patent Application Laid-Open No. 2015-107301) in which the distal end portion of the device is inserted into the biological lumen. It also includes those that are temporarily detained.

Further, for example, the gear train of the moving mechanism is not limited to the configuration shown in the embodiment as long as it has a configuration capable of transmitting the operation of the handle to the rack.

In addition, in the embodiment, the configuration in which the sheath 11 is moved proximally with respect to the tubular member 12 to release the stent graft 14 has been described. It can also be applied to a medical device that emits a medical treatment tool by allowing it to move. That is, according to the present invention, when the first gear rotates with the operation of the handle, the fixed portion moves axially along the rack, moving the tubular member distally with respect to the sheath, thereby providing a medical treatment instrument. can be applied to medical devices in which is released into a biological lumen.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

1 Stent graft placement system (medical device)
10 Catheter Section 11 Sheath 12 Tubular Member 13 Inner Rod 14 Stent Graft (Medical Treatment Instrument)
20 Operation Part 21 Front Cover 22 Cover Body 23 Front Handle (Handle)
24 rear handle 25 gearbox (fixed part, second member)
26 trigger (first member)
27 gear train (moving mechanism)
271 first gear 272 second gear 273 third gear 274 first gear shaft 275 second gear shaft 28 rack (moving mechanism)
29 rod guide shaft 31 first spring 32 second spring

Claims (6)

A medical device for placing a medical treatment instrument in a biological lumen,
a sheath;
a tubular member having a medical treatment instrument disposed at its distal end and inserted through the sheath;
an operation unit provided on the rear end side of the sheath and the tubular member and configured to move the sheath and the tubular member relative to each other in an axial direction;
The operation unit is
a fixing part that fixes the sheath or the tubular member;
a moving mechanism for moving the fixed portion in the axial direction;
a cover that accommodates the fixing part;
The moving mechanism is
a rack provided inside the cover along the axial direction;
a gear train including a first gear supported by the fixed portion and meshing with the rack;
a handle for operating the gear train;
When the first gear rotates with the operation of the handle, the fixing portion axially moves along the rack, and at least one of the sheath and the tubular member axially moves relative to each other. A medical device, wherein the medical treatment instrument is released into the biological lumen. The rack and the first gear are configured to be switchable between an engaged state and a separated state,
The medical device according to claim 1, wherein the fixing portion is movable in the axial direction when the rack and the first gear are separated from each other. The gear train has a second gear that meshes with the first gear,
the handle has a worm on its inner peripheral surface that meshes with the second gear;
3. The medical device of claim 1 or 2, wherein rotating the handle about the axial direction rotates the second gear and the first gear. 4. The medical device according to claim 3, wherein the gear train has a third gear coaxially arranged with the first gear and meshing with the second gear. The fixed part is
a first member that supports the first gear;
a second member that supports the second gear;
a biasing member that is interposed between the first member and the second member and biases the first member in a direction in which the first gear meshes with the rack to maintain the meshing state. The medical device according to claim 3 or 4, characterized in that: The second member has a restricting portion that restricts the first member from being pushed in against the biasing force of the biasing member,
The first member is configured to be movable in the axial direction with respect to the second member, and as the first member moves in the axial direction, the restriction by the restricting portion is released and the first member can be pushed. 6. The medical device of claim 5.

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