WO2012039204A1

WO2012039204A1 - Medical device

Info

Publication number: WO2012039204A1
Application number: PCT/JP2011/068060
Authority: WO
Inventors: 俊明高木; 陽祐大谷; 佑輔関根; 隆介高重
Original assignee: テルモ株式会社
Priority date: 2010-09-24
Filing date: 2011-08-08
Publication date: 2012-03-29

Abstract

Provided is a medical device capable of securing a prescribed space for treatment, etc. of a desired area in the brain. A sheath (1) along with an expanding tool (3) is inserted into a brain region (B) with the expanding tool (3) accommodated inside the sheath (1). By retracting the sheath (1) relative to the inner cylindrical component (2) when the leading end of the sheath (1) reaches the site requiring observation, treatment, etc. so that the expanding tool (3) disposed at the leading end of the inner cylindrical component (2) protrudes forward from the opening of the leading end of the sheath (1), the multiple arms (5) of the expanding tool (3) are released from the restraint of the sheath (1), the expanding tool (3) expands autonomously outward in the radial direction of the sheath (1), and the prescribed space (S) is formed in the brain region (B).

Description

Medical device

The present invention relates to a medical device, and more particularly to a medical device that secures a predetermined space for observation, treatment, etc. in a brain region.

Conventionally, treatment of the brain in the skull, that is, treatment of a so-called brain region, has been performed by making a large incision in the skull that covers the outer periphery of the brain by craniotomy. Such craniotomy imposes a heavy burden on the patient and requires a long time for recovery after the operation. For this reason, it is anxious to treat the brain region without large craniotomy.

As a means for administering a therapeutic substance such as a drug solution, a neurotrophic factor, an information transmission substance, a gene, or a cell to an affected part existing in the brain area, a method of inserting a medical instrument such as a catheter into the brain area can be considered.
However, when approaching the brain region from the skull, since there is no catheter insertion passage in the brain region, medical devices can be easily placed in the brain region, as in blood vessels that are generally treated with catheters. The fact is that it cannot be inserted into the affected area. Since many nerve cells are gathered on the surface of the brain tissue, a medical device must be inserted without damaging these nerve cells. Even if a medical instrument can be inserted into the brain region, since the brain tissue is soft, the position of the medical instrument is not stable, and there is a possibility that treatment with the medical instrument may be extremely difficult.
If a predetermined stable space for treatment or the like can be secured at a desired location in the brain region, it is possible to insert a medical instrument and perform a treatment with the medical instrument without damaging the brain tissue. Become.

Patent Document 1 proposes a stent for expanding the patient's throat and preventing airway obstruction.

JP 2003-265621 A

By inserting the stent disclosed in Patent Document 1 from the patient's nasal cavity and attaching it to the throat, the stent expands to secure a space that allows air to flow through the throat.
However, this stent has a diameter of only about 12 mm at the thickest part and about 2 to 4 mm at the end, and has a poor expansion force. For this reason, it is difficult to form a large space into which a medical instrument is inserted in the brain region.
Further, in order to expand the brain tissue and secure a treatment space, it is necessary to have an expansion force enough to withstand the pressing force from the brain tissue.

The present invention has been made to solve such conventional problems, and provides a medical device capable of securing a predetermined space for treatment or the like at a desired location in a brain region. With the goal.

The medical device according to the present invention has a sheath having an opening at the tip, and is inserted into the sheath so as to be movable forward and backward with respect to the sheath and autonomously projects in the radial direction of the sheath when protruding forward from the opening of the sheath. An expander having a plurality of arms that extend outward and an operating means for moving the expander back and forth with respect to the sheath.

Preferably, the sheath is inserted into the brain region, and in this state, the plurality of arms are autonomously moved by retracting the sheath relative to the dilator until the dilator projects forward from the opening of the sheath. By expanding, a predetermined space is formed in the brain region.
The expansion tool can include a sheet that covers the entirety of the plurality of arm portions and is stretched when the plurality of arm portions are expanded.
Moreover, it is good also as a structure which a some arm part expands with the elasticity which it has.

Or the expansion tool may contain the elastic member for expanding a some arm part.
In this case, the expander includes a shaft portion extending in the axial direction of the sheath, a slider that is disposed so as to be able to advance and retreat along the shaft portion, and is biased forward by the elastic member, and the slider and the plurality of arm portions. A plurality of link portions to be connected, and when the expander protrudes forward from the opening portion of the sheath, the slider advances by the elastic member along the shaft portion, and the plurality of arm portions are connected via the plurality of link portions. It can be configured to expand radially.
As the elastic member, an annular spring that is coupled to the plurality of arm portions and urges the plurality of arm portions outward in the radial direction of the sheath can also be used.
Furthermore, as the elastic member, a plurality of springs may be used that are arranged between adjacent arm portions and urge the adjacent arm portions outward.

According to the present invention, when the dilator protrudes forward from the opening of the sheath, the plurality of arm portions autonomously expands outward in the radial direction of the sheath. Therefore, it is possible to secure a predetermined space.

It is side surface sectional drawing which shows the structure of the front-end | tip part of the medical device which concerns on Embodiment 1 of this invention. 3 is a front view showing a distal end portion of the medical device according to Embodiment 1. FIG. In the medical device which concerns on Embodiment 1, it is side surface sectional drawing which shows the state which retracts a sheath with respect to an expansion tool. In the medical device which concerns on Embodiment 1, it is a side sectional view which shows the state which the expansion tool expanded. In the medical device which concerns on Embodiment 1, it is a front view which shows the state which the expansion tool expanded. The mode at the time of use of the medical device which concerns on Embodiment 1 is shown, (A) is a fragmentary sectional view of the brain area | region where the medical device was inserted, (B) is the part of the brain area | region when an expansion tool expands It is sectional drawing. It is a fragmentary sectional view showing the inside of a skull. In the medical device which concerns on Embodiment 2, it is side surface sectional drawing which shows the state which the expansion tool expanded. In the medical device which concerns on Embodiment 2, it is a front view which shows the state which the expansion tool expanded. FIG. 10 is a side cross-sectional view illustrating a configuration of a distal end portion of a medical device according to Embodiment 3. 10 is a front view showing a distal end portion of a medical device according to Embodiment 3. FIG. In the medical device which concerns on Embodiment 3, it is side surface sectional drawing which shows the state which the expansion tool expanded. In the medical apparatus which concerns on Embodiment 3, it is a front view which shows the state which the expansion tool expanded. In the medical device which concerns on Embodiment 4, it is a sectional side view which shows the state which the expansion tool expanded. In the medical apparatus which concerns on Embodiment 4, it is a front view which shows the state which the expansion tool expanded. In the medical device which concerns on Embodiment 5, it is side surface sectional drawing which shows the state which the expansion tool expanded. In the medical apparatus which concerns on Embodiment 5, it is a front view which shows the state which the expansion tool expanded. In the medical device which concerns on the modification of Embodiment 5, it is side surface sectional drawing which shows the state which the expansion tool expanded. In the medical device which concerns on the modification of Embodiment 5, it is a front view which shows the state which the expansion tool expanded. In the medical device which concerns on the other modification of Embodiment 5, it is a sectional side view which shows the state which the expansion tool expanded. In the medical apparatus which concerns on the other modification of Embodiment 5, it is a front view which shows the state which the expansion tool expanded. FIG. 10 is a front view showing a distal end portion of a medical device according to a sixth embodiment. In the medical device which concerns on Embodiment 6, it is side surface sectional drawing which shows the state which the expansion tool expanded. In the medical apparatus which concerns on Embodiment 6, it is a front view which shows the state which the expansion tool expanded. In the medical device which concerns on Embodiment 7, it is side surface sectional drawing which shows the state which the expansion tool expanded.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows the configuration of the distal end portion of the medical device according to the first embodiment. The medical device has a sheath 1, an inner cylinder member 2 is inserted into the sheath 1 so as to be able to advance and retreat, and an expander 3 is disposed at a distal end portion of the inner cylinder member 2. The distal end of the sheath 1 is opened, and an opening 4 is formed here. The expansion tool 3 is formed integrally with the inner cylinder member 2, and the expansion tool 3 moves forward and backward in the sheath 1 together with the inner cylinder member 2 by moving the inner cylinder member 2 forward and backward with respect to the sheath 1. That is, the inner cylinder member 2 functions as an operating means for moving the expander 3 forward and backward with respect to the sheath 1.

As shown in FIG. 2, the expander 3 has eight arm portions 5 that are divided in the circumferential direction of the sheath 1 and extend along the axial direction of the sheath 1. Each of these arm portions 5 is provided in advance with elasticity so as to expand by bending or bending outward in the radial direction of the sheath 1 with respect to the inner cylindrical member 2.
For this reason, as shown in FIG. 1, when the expander 3 is housed inside the sheath 1, each arm portion 5 is constrained by the inner wall of the sheath 1, and the shaft of the sheath 1 does not expand outward. The sheath 1 gradually retreats relative to the inner cylinder member 2 and the dilator 3 as shown in FIG. 3, and the dilator 3 is opened in the sheath 1 as shown in FIG. 4. If it protrudes ahead from the part 4, it will be released from restraint by the sheath 1, and each arm part 5 will be curved or bent outward by its own elasticity to expand. In this way, the eight arm portions 5 radially expand outward, and the expander 3 autonomously expands radially outward of the sheath 1.

At this time, as shown in FIG. 5, the length and elasticity of each arm portion 5 are set in advance so that the tip of each arm portion 5 extends outward from the outer peripheral portion of the sheath 1.
Conversely, when the expander 3 is retracted with respect to the sheath 1 from the state in which the expander 3 protrudes forward from the opening 4 of the sheath 1 and expands as shown in FIG. 4, each arm portion 5 is restrained by the sheath 1. Then, the dilator 3 gradually contracts and is housed inside the sheath 1 as shown in FIG. Note that the dilator 3 may be housed inside the sheath 1 by advancing the sheath 1 relative to the dilator 3.

Next, a method for forming a predetermined space for observation, treatment, etc. in the brain region using the medical device according to the first embodiment will be described.
First, as shown in FIG. 1, the medical device according to the first embodiment in a state where the dilator 3 is housed in the sheath 1, as shown in FIG. Insert inside. Since nerve cells are gathered on the surface of the brain tissue forming the brain region B, the medical device is inserted while scraping the brain tissue.
Then, when the distal end of the sheath 1 reaches the vicinity where observation, treatment or the like is required, insertion of the medical device is stopped, and in this state, the sheath 1 is moved backward relative to the inner cylinder member 2. As a result, the expander 3 arranged at the tip of the inner cylinder member 2 is caused to protrude forward from the opening 4 of the sheath 1. As a result, the eight arm portions 5 of the expander 3 are released from the restraint by the sheath 1, and the expander 3 autonomously expands outward in the radial direction of the sheath 1, as shown in FIG. 6B. . As a result, the surface of the brain tissue is pressed by the eight arms 5 of the dilator 3, the brain tissue is expanded, and a predetermined space S is formed and secured in the brain region B.

After forming the predetermined space S in this way, an endoscope (not shown) is inserted into the inner cylindrical member 2 and the distal end portion of the endoscope protrudes into the space S. Can be observed. Similarly, by inserting a treatment tool into the space S through the inside of the inner cylindrical member 2, a therapeutic substance such as a drug solution, a neurotrophic factor, a signal transmitting substance, a gene, a cell, or the like is applied to the affected part in the brain region B It can also be administered.

Here, FIG. 7 shows the inside of the skull. The brain is protected by being wrapped in a three-layer membrane of connective tissue called the meninges. The outermost dura mater is in close contact with the skull 11, and the brain position is maintained by this dura mater. The middle meninges, called spider membranes, consist of fine connective tissue fibers and contain cerebrospinal fluid between the innermost buffy coat. That is, the brain is floating in the cerebrospinal fluid. The brain has a cerebrum 12 and a cerebellum 13. The cerebrum 12 is divided into a right brain 15 and a left brain 16 by a longitudinal cerebral fissure 14. A ventricle including the third ventricle 17 is located at the bottom of the skull, and there are abundant blood vessels in the ventricle, and cerebrospinal fluid is secreted from the choroid plexus in the ventricle. The cerebrospinal fluid circulates in the space under the arachnoid and is then absorbed into the vein from the cerebral venous sinus 18.

When observing or treating the side surface of the longitudinal cerebral fissure 14 or the third ventricle 17, first, an opening is provided in the forehead, and an insertion port 19 shown in FIG. 7 is attached to this opening. The insertion port 19 can insert the medical device according to the first embodiment, but preferably includes a valve so that cerebrospinal fluid, blood, or the like does not flow outside. The medical device shown in FIG. 1 is inserted from the insertion port 19, and the distal end of the sheath 1 is positioned in the longitudinal cerebral fissure 14, or the distal end of the sheath 1 is inserted into the third cerebral ventricle 17 through the longitudinal cerebral fissure 14. Position it in front.
In this state, by retracting the sheath 1 relative to the inner cylinder member 2, the expander 3 protrudes forward from the opening 4 of the sheath 1, and the expander 3 autonomously has a diameter of the sheath 1. A predetermined space S is formed by expanding outward in the direction. As described above, observation, treatment, and the like can be performed by inserting an endoscope, a treatment tool, or the like into the inner cylinder member 2.

The material for forming the sheath 1 is preferably a material having a certain degree of flexibility. For example, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyurethane Thermoplastic resins such as polyamide, polyamide elastomer, polyimide, silicone resin, polyether / ethyl ketone, and polyester elastomer can be used.

On the other hand, the material for forming the expander 3 is preferably a material having elasticity and a certain degree of rigidity. For example, metal materials such as stainless steel, aluminum alloy, superelastic metal, shape memory alloy, polyamide, polyvinyl chloride, Resin materials such as polycarbonate, ABS, polyethylene, polypropylene, Teflon (registered trademark), and acrylic resin can be used.
The expansion tool 3 forms eight arm portions 5 by equally inserting eight notches of a predetermined length along the axial direction of the tubular member into the tubular member made of the above forming material. Each of the arm portions 5 can be formed by bending or bending outward in the radial direction.

The inner cylinder member 2 can be formed integrally with the expansion tool 3 using the same material as that of the expansion tool 3. Alternatively, after forming the inner cylinder member 2 from a material different from the expansion tool 3, the expansion tool 3 may be fixed to the distal end portion of the inner cylinder member 2. The inner cylinder member 2 may be made of a material different from that of the expansion tool 3. In the case of forming, the same material as that for forming the sheath 1 described above can be used as the material for forming the inner cylinder member 2.
In Embodiment 1, the sheath 1 is retracted with respect to the dilator 3 so that the dilator 3 protrudes forward from the opening 4 of the sheath 1. However, the dilator 3 is attached to the sheath 1. On the other hand, the dilator 3 may protrude forward from the opening 4 of the sheath 1 by being advanced.

Embodiment 2
FIG. 8 shows the configuration of the distal end portion of the medical device according to the second embodiment. This medical device uses the expansion tool 21 instead of the expansion tool 3 in the medical device of the first embodiment. The extension tool 21 includes not only the eight arm portions 5 similarly to the extension tool 3 in the first embodiment, but also a sheet 22 that covers the entire arm portions 5. When the expander 21 is housed in the sheath 1, the seat 22 is folded between the adjacent arm portions 5, and the expander 21 protrudes forward from the opening 4 of the sheath 1. When expanded, as shown in FIG. 9, it is stretched by the eight arm portions 5.

By using such a sheet 22, when the dilator 21 is expanded, the contact area with the brain region B is increased, and the surface of the brain tissue forming the brain region B is entirely expanded to form a predetermined space. S can be formed.
The sheet 22 is preferably fixed to the outside of the eight arm portions 5 of the extension tool 3. Moreover, the sheet | seat 22 does not necessarily need to cover the expansion tool 3 whole, and may cover only a part of surface.

The material for forming the sheet 22 is not particularly limited as long as it is flexible, and examples thereof include polyurethane, polyethylene, polyester, polypropylene, polyamide, polytetrafluoroethylene, and polyvinylidene fluoride.
Further, the sheet 22 is not particularly limited as long as it has flexibility. For example, the sheet 22 can be formed from a nonwoven fabric, a woven or knitted fabric using the above-described forming material.

Embodiment 3
FIG. 10 shows the configuration of the distal end portion of the medical device according to the third embodiment. This medical device uses the expansion tool 31 instead of the expansion tool 3 in the medical device of the first embodiment. The extension tool 31 has not only the eight arm portions 5 like the extension tool 3 in the first embodiment, but also the base end portion of the tubular shaft portion 32 is fixed to the inner periphery of the distal end of the inner cylinder member 2. Thus, the shaft portion 32 extends in the axial direction of the inner cylindrical member 2, that is, the axial direction of the sheath 1, and a cylindrical or annular slider 33 is movably moved along the shaft portion 32 on the outer peripheral portion of the shaft portion 32. The slider 33 and the eight arm portions 5 are connected to each other by rod-shaped link portions 34. One end of each link portion 34 is rotatably connected to the slider 33, and the other end is rotatably connected to an intermediate portion of the corresponding arm portion 5.
An annular step 35 is formed on the outer peripheral portion of the base end side of the shaft portion 32, and a coil spring 36 is fitted between the step portion 35 and the slider 33 so as to cover the outer periphery of the shaft portion 32. It is.

As shown in FIGS. 10 and 11, when the expander 31 is housed in the sheath 1, each arm portion 5 is restrained by the inner wall of the sheath 1 and extends in the axial direction of the sheath 1, and as a result. The slider 33 is retracted toward the proximal end side of the shaft portion 32 against the elastic force of the coil spring 36 via the link portion 34. That is, the coil spring 36 is contracted, and the slider 33 is biased forward by the coil spring 36.
For this reason, when the expander 31 is protruded forward from the opening 4 of the sheath 1 by retreating the sheath 1 relative to the inner cylinder member 2, as shown in FIG. 12 and FIG. 33 receives the urging force of the coil spring 36 and moves forward along the shaft portion 32. As the slider 33 moves forward, the eight arm portions 5 expand radially outwardly via the link portion 34, and the expander 31 autonomously expands radially outward of the sheath 1.

As with the extension tool 21 in the second embodiment described above, the entire eight arm portions 5 are covered with the sheet 22, and when the sheet 22 is stretched, the further expansion of the arm portion 5 is restrained. Then, the advance of the slider 33 is stopped.
According to the third embodiment, since the elastic force of the coil spring 36 is used, the expander 31 can be expanded even if the arm portions 5 do not have elasticity that expands outward in the radial direction of the sheath 1 in advance. Thus, a predetermined space can be formed inside the brain region or the like.

Embodiment 4
An extension tool 41 as shown in FIGS. 14 and 15 can also be used as the extension tool. This extension tool 41 is different from the extension tool 31 in the third embodiment shown in FIG. 12 in that the slider 33, the link portion 34, and the coil spring 36 are omitted, but the shaft portion 32 and the eight arm portions 5 are not provided. Coil springs 42 are respectively arranged. These coil springs 42 urge the corresponding arm portions 5 outward in the radial direction of the sheath 1.

When the expander 41 is housed inside the sheath 1, the coil spring 42 is in a contracted state. When the expander 41 is protruded forward from the opening 4 of the sheath 1, the coil spring 42 is biased. The eight arm portions 5 expand radially outward, and the expansion tool 41 autonomously expands radially outward of the sheath 1.
As described above, since the elastic force of each coil spring 42 is used, even if the arm portion 5 does not have elasticity that expands outward in the radial direction of the sheath 1, it is the same as in the first to third embodiments described above. In addition, a predetermined space can be formed inside the brain region or the like. Further, the expansion force of the expansion tool 41 can be adjusted by adjusting the strength of the coil spring 42.
Instead of the coil spring 42, a leaf spring may be disposed between the shaft portion 32 and the eight arm portions 5, respectively.

Embodiment 5
FIG. 16 shows the configuration of the distal end portion of the medical device according to the fifth embodiment. This medical device uses an expansion tool 51 instead of the expansion tool 21 in the medical device of the second embodiment. The expander 51 is obtained by disposing an annular coil spring 52 inside the eight arm portions 5 in the expander 21 according to the second embodiment shown in FIG. As shown in FIG. 17, the coil springs 52 are connected to the eight arm portions 5, respectively, and urge the arm portions 5 outward in the radial direction of the sheath 1.

When the expander 51 is housed in the sheath 1, the annular coil spring 52 is in a contracted state. When the expander 51 is protruded forward from the opening 4 of the sheath 1, the coil spring 52 is biased. Then, the eight arm portions 5 radially expand outward, and the expansion tool 51 autonomously expands outward in the radial direction of the sheath 1.
As described above, since the elastic force of the annular coil spring 52 is used, even if the arm portions 5 themselves do not have elasticity, a predetermined amount is provided inside the brain region or the like as in the first to fourth embodiments. A space can be formed.

Further, instead of connecting the annular coil spring 52 to the eight arm portions 5, coil springs 62 are arranged between the adjacent arm portions 5, as in the extension tool 61 shown in FIGS. 18 and 19. The arm portions 5 may be configured to bias each other outward.
When the expander 61 is housed inside the sheath 1, each coil spring 62 is in a contracted state. When the expander 61 is projected forward from the opening 4 of the sheath 1, the coil spring 62 is biased. Then, the arm portions 5 adjacent to each other move away from each other, so that the eight arm portions 5 expand radially outward and the expander 61 autonomously expands radially outward of the sheath 1.

A leaf spring can be used instead of the coil spring 62. That is, like the extension tool 71 shown in FIGS. 20 and 21, the plate springs 72 are arranged between the adjacent arm portions 5 to urge these arm portions 5 outward.
When the extension tool 71 is housed in the sheath 1, the respective leaf springs 72 are in a folded state. When the extension tool 71 is protruded forward from the opening 4 of the sheath 1, the attachment of the leaf spring 72 is performed. By moving the arm portions 5 adjacent to each other so as to be separated from each other due to the force, the eight arm portions 5 radially expand outward, and the expansion tool 71 autonomously outwards in the radial direction of the sheath 1. Expand.

Embodiment 6
In Embodiments 1 to 5 described above, each expansion tool has eight arm portions 5 that are divided in the circumferential direction of the sheath 1 and extend along the axial direction of the sheath 1. However, if two or more arm portions are provided, a predetermined space can be formed by expanding these arm portions.
For example, the expansion tool 81 used in the medical device of the sixth embodiment shown in FIG. 22 has four arm portions 82 divided into four in the circumferential direction. Further, coil springs 83 are respectively disposed between the adjacent arm portions 82, and these arm portions 82 are urged outward by the coil spring 83.

As shown in FIG. 22, when the expander 81 is housed inside the sheath 1, each coil spring 83 is in a contracted state, and when the expander 81 is protruded forward from the opening 4 of the sheath 1. As shown in FIGS. 23 and 24, the arm portions 82 adjacent to each other are moved away from each other due to the biasing force of the coil spring 83, so that the four arm portions 82 are radially spread outward. The expander 81 autonomously expands outward in the radial direction of the sheath 1.

Similar to the extension tool 21 in the second embodiment described above, the entire four arm portions 82 are covered with the sheet 22, and when the extension tool 81 is expanded, as shown in FIG. It is stretched by the four arm portions 82.
Since the elastic force of each coil spring 83 is used, a predetermined space is formed inside the brain region or the like, as in the first to fifth embodiments, even if the arm portions 82 themselves do not have elasticity. It becomes possible.

Embodiment 7
In the above first to sixth embodiments, each expansion tool has a plurality of

arm portions

5 or 82 that extend in a straight line and expands into a substantially pyramid shape. However, the present invention is not limited to this. The arm portions may not be linear as long as they can be stored in each other and can spread out to form a predetermined space when protruding forward from the sheath 1.
For example, the expander 91 used in the medical device of the seventh embodiment shown in FIG. 25 has eight arm portions 92 each having a bent shape so that the intermediate portion is convex outward. is doing. Each of these arm portions 92 is previously provided with elasticity so as to expand outward in the radial direction of the sheath 1 with respect to the inner cylindrical member 2.

For this reason, when the expander 91 is housed in the sheath 1, each arm portion 92 is restrained by the inner wall of the sheath 1 and extends in the axial direction of the sheath 1. 25, the arms 92 are released from restraint by the sheath 1 as shown in FIG. 25, and each arm portion 92 expands outward due to its own elasticity and the intermediate portion faces outward. Bent in a convex shape. In this way, the eight arm portions 92 radially expand outward, and the expander 91 autonomously expands outward in the radial direction of the sheath 1, so that an octagonal pyramid and an octagonal prism are placed inside the brain region and the like. It is possible to form a space having a shape such that these are combined.

In addition, although each arm part 92 was bent so that an intermediate part may become convex, it can also be made into a curved shape.
Further, the number of arm portions 92 is not limited to eight and may be two or more.
In this way, by selecting the shape and number of the arm portions 92, it is possible to form a space having a desired shape inside the brain region or the like.

Also in the extension tool 91 according to the seventh embodiment, the entire eight arm portions 92 can be covered with a sheet, as in the second embodiment described above.
Further, the extension tool 91 is expanded by the elasticity of each arm part 92 itself, but the extension tool 91 is extended by an elastic member different from the arm part 92 as in the third to sixth embodiments. Also good.

In Embodiments 1 to 7 described above, the inner cylinder member 2 is used as an operation means for moving each expansion tool forward and backward with respect to the sheath 1, but, for example, a wire can also be used as the operation means. The expander may be advanced and retracted by fixing the expander at the tip of the wire and inserting the wire into the sheath 1 and inserting and removing the wire from the sheath 1.

1 sheath, 2 inner cylinder member, 3, 21, 31, 41, 51, 61, 71, 81, 91 dilator, 4 openings, 5, 82, 92 arm part, 11 skull, 12 cerebrum, 13 cerebellum, 14 Longitudinal cerebrum, 15 right brain, 16 left brain, 17 3rd ventricle, 18 cerebral venous sinus, 19 insertion port, 22 sheets, 32 shaft part, 33 slider part, 34 link part, 35 step part, 36, 42, 52, 62 , 83 Coil spring, 72 leaf spring, B brain region, S space.

Claims

A sheath having an opening at the tip;
An expander having a plurality of arms that are inserted into the sheath so as to be capable of advancing and retreating with respect to the sheath and autonomously expand outward in the radial direction of the sheath when protruding forward from the opening of the sheath; ,
An operation device for moving the expansion tool forward and backward with respect to the sheath.
With the sheath inserted into the brain region, the operating means moves the dilator relative to the sheath until the dilator projects forward from the opening of the sheath, and the arms The medical device according to claim 1, wherein a predetermined space is formed in the brain region by autonomously expanding the part.
The medical device according to claim 1 or 2, wherein the expander includes a sheet that covers the entirety of the plurality of arm portions and is stretched when the plurality of arm portions are expanded.
The medical device according to any one of claims 1 to 3, wherein the plurality of arm portions are expanded by elasticity of the plurality of arms.
The medical device according to any one of claims 1 to 3, wherein the expansion tool includes an elastic member for expanding the plurality of arm portions.
The dilator is
A shaft portion extending in the axial direction of the sheath;
A slider that is arranged so as to be able to advance and retreat along the shaft portion and is biased forward by the elastic member;
A plurality of link portions connecting the slider and the plurality of arm portions, and the slider is moved along the shaft portion by the elastic member when the expander projects forward from the opening of the sheath. The medical device according to claim 5, wherein the medical device moves forward and the arm portions are radially expanded through the plurality of link portions.
The medical device according to claim 5, wherein the elastic member includes an annular spring that is connected to the plurality of arm portions and biases the plurality of arm portions outward in the radial direction of the sheath.
The medical device according to claim 5, wherein the elastic member includes a plurality of springs that are arranged between the adjacent arm portions and urge the adjacent arm portions outward.