Patent Publication Number: US-2021177704-A1

Title: Gastrostomy catheter, insertion jig set, insertion jig and gastrostomy catheter set

Description:
TECHNICAL FIELD 
     The present invention relates to a gastrostomy catheter, an insertion jig set which is used when the gastrostomy catheter is attached into a stomach, an insertion jig, and a gastrostomy catheter set. 
     Priority is claimed on Japanese Patent Application No. 2017-232868, filed on Dec. 4, 2017, Japanese Patent Application No. 2018-145805, filed on Aug. 2, 2018, and Japanese Patent Application No. 2018-154832, filed on Aug. 21, 2018, the contents of which are incorporated herein by reference. 
     BACKGROUND ART 
     In the related art, as gastrostomy catheters, a gastrostomy catheter is known, which is configured to administer a nutrient into a stomach and to place a tip portion of the catheter in the stomach by a gastrointestinal fixing portion (gastrointestinal indwelling device) such as an expandable bumper or balloon in order to maintain a state in which the nutrient can be administered into the stomach. 
     Specifically, there is a gastrostomy catheter having a bumper of which a diameter is reduced by a rod, as disclosed in PTL 1, or a gastrostomy catheter having a balloon which is inflated or deflated by a fluid such as an aqueous salt solution, as disclosed in Patent Document 2. 
     When a gastrostomy catheter is attached to a body, it is important to avoid or suppress the gastrointestinal fixing portion from compressing or damaging a wall surface of a fistula, thereby reducing a burden on a subject. 
     For example, PTL 3 discloses a gastrostomy catheter insertion jig set (described as a gastrostomy instrument in PTL 3) including a cap (described as a capsule in PTL 3) which covers an gastrointestinal fixing portion (described as an internal bolster in PTL 3) and can maintain a state in which the gastrointestinal fixing portion is folded. 
     In the insertion jig set described in PTL 3, the gastrointestinal fixing portion can be inserted into a stomach through a fistula in a state in which the gastrointestinal fixing portion is folded by a cap, and thus, a burden on a subject is reduced. A hole through which a lip cord (tear string) can pass is formed in this cap. The cap is torn by pulling the lip cord which has passed through the hole, and the state is shifted from a state in which the gastrointestinal fixing portion is restrained to a state in which the gastrointestinal fixing portion is expandable. Accordingly, the gastrointestinal fixing portion is placed into the stomach. 
     CITATION LIST 
     Patent Literature 
     [PTL] Japanese Unexamined Patent Application, First Publication No. 2003-180841 
     [PTL 2] Published Japanese Translation No. 2002-534168 of the PCT International Publication 
     [PTL 3] Published Japanese Translation No. 2005-511206 of the PCT International Publication 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the gastrostomy catheter of PTL 1, since it is necessary to stably place the bumper in the stomach, it is difficult to use a highly flexible bumper. Therefore, when the gastrostomy catheter is inserted into the fistula or removed from the fistula, a large resistance may be applied to a wall surface portion of the fistula from the bumper. In order to reduce the burden on the body, it is desirable that the resistance is smaller. 
     In the balloon catheter of PTL 2, since it is necessary to replace a fluid which fills the balloon, it takes time and effort required for management, and it is difficult to place the balloon catheter for a long time. 
     In the insertion jig set described in PTL 3, the cap is torn by the lip cord. Accordingly, since there is no mechanism for separating the cap from the gastrointestinal fixing portion, there is a concern that the torn cap is left in a state of being attached to the gastrointestinal fixing portion. In this case, there is a concern that the shifting of the gastrointestinal fixing portion from the folded state to the expanded state may be hindered. 
     In addition, it is necessary to provide the hole for the lip cord to pass through in the cap, and it is necessary that the cap has a thickness and a material that can be torn by the lip cord. Accordingly, a holding force for maintaining the state in which the gastrointestinal fixing portion is folded may be restricted. For this reason, in a case where this cap is used for a gastrointestinal fixing portion having high elasticity, elastic restoration of the gastrointestinal fixing portion cannot be suppressed. Accordingly, it is possible that the cap is unexpectedly detached from the gastrointestinal fixing portion. 
     Furthermore, it is difficult for a surgeon to obtain confirmation that the cap is detached from the gastrointestinal fixing portion only by pulling the lip cord. 
     The present invention is made in consideration of the above-described problems, and object thereof is to provide a gastrostomy catheter capable of reducing time and effort required for management while keeping a resistance applied to a body low and capable of being placed for a relatively long time. 
     In addition, another object of the present invention is to provide an insertion jig set, an insertion jig, and a gastrostomy catheter set capable of preventing the cap from being unexpectedly detached from the gastrostomy catheter and capable of suitably removing the cap. 
     Solution to Problem 
     According to an aspect of the present invention, there is provided a gastrostomy catheter including: a shaft in which a lumen is provided; a flexible bumper which is provided at a tip of the shaft; and a linear member which has elasticity and biases the bumper in a diameter-increasing direction or restricts deformation of the bumper in a diameter-decreasing direction. 
     According to another aspect of the present invention, there is provided an insertion jig set for inserting a gastrostomy catheter having a foldable gastrointestinal fixing portion at a tip into a body, the insertion jig set including: an insertion jig configured to include a tubular mantle portion and an inner insertion portion which is movable forward and rearward through the mantle portion; the gastrostomy catheter which is attached around the mantle portion; and a cap which is disposed on a tip side of the mantle portion and covers at least a portion of the folded gastrointestinal fixing portion, in which one of the gastrostomy catheter or the mantle portion and the cap has a locking portion which is locked to the other, and the inner insertion portion releases locking by the locking portion when the inner insertion portion moves forward through the mantle portion. 
     According to still another aspect of the present invention, there is provided an insertion jig for inserting a gastrostomy catheter having a foldable gastrointestinal fixing portion at a tip and a cap covering at least a portion of the folded gastrointestinal fixing portion into a body, the insertion jig including: a tubular mantle portion around which the gastrostomy catheter is attachable; and an inner insertion portion which passes through the mantle portion, in which the mantle portion has a locking portion which is locked to the cap, and the inner insertion portion releases locking by the locking portion when the inner insertion portion moves forward through the mantle portion. 
     According to still another aspect of the present invention, there is provided a gastrostomy catheter set including: a gastrostomy catheter which has a foldable gastrointestinal fixing portion at a tip; and a cap which covers at least a portion of the folded gastrointestinal fixing portion, in which the gastrostomy catheter is formed so that a portion of an insertion jig for inserting the gastrostomy catheter into the stomach is inserted, and the cap has a locked portion which is locked to the insertion jig. 
     Advantageous Effects of Invention 
     According to the gastrostomy catheter of the present invention, the linear member is provided, which can bias the bumper in a diameter-increasing direction or restrict deformation of the bumper in the diameter-decreasing direction. Accordingly, it is possible to use the bumper made of a material which is more flexible than the gastrostomy catheter of the related art. Accordingly, it is possible to suppress a resistance applied to a body when the catheter is inserted or removed to a low level. Moreover, unlike a gastrostomy catheter having a balloon, a fluid is not used. Accordingly, there is no need to replace the fluid. Therefore, compared with the gastrostomy catheter provided with the balloon, time and effort required for management can be reduced, and the gastrostomy catheter can be placed for a relatively long time. 
     According to the insertion jig set, the insertion jig, and the gastrostomy catheter set of the present invention, it is possible to suitably remove the cap while preventing the cap from being unexpectedly removed from the gastrostomy catheter. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of a gastrostomy catheter according to the present embodiment. 
         FIG. 2  is a front cross-sectional view of the gastrostomy catheter. 
         FIG. 3  is a bottom view of a bumper when viewed in a direction of an arrow  1 III in  FIG. 1 . 
         FIG. 4  is an explanatory view for explaining an angle of each site of a wire with respect to an inner peripheral surface of the bumper. 
         FIG. 5  is a schematic explanatory view illustrating a state of the gastrostomy catheter in which the bumper is placed in a stomach. 
         FIG. 6  is a schematic explanatory view illustrating a state in which the gastrostomy catheter is inserted into the stomach through a fistula. 
         FIG. 7  is a schematic explanatory view illustrating a state in which a cover is removed from the gastrostomy catheter by an insertion jig and the bumper is expanded. 
         FIG. 8  is a schematic explanatory view illustrating a state of the gastrostomy catheter in a state in which a base end holding portion is removed from the extracorporeal fixing unit. 
         FIG. 9  is a schematic explanatory view illustrating a state in which the gastrostomy catheter is removed from an inside of the stomach. 
         FIG. 10  is a front cross-sectional view illustrating an extracorporeal fixing unit according to Modification Example 1-1. 
         FIG. 11  is a bottom view illustrating a communication hole of the bumper according to Modification Example 1-2. 
         FIG. 12  is a front cross-sectional view illustrating a tip portion of a sub-lumen according to Modification Example 1-3. 
         FIG. 13  is a perspective view illustrating a bumper and a shaft to which the bumper is attached according to a Modification Example 1-4. 
         FIG. 14  is a perspective view illustrating an inner layer of the bumper by removing an outer layer of the bumper and corresponds to  FIG. 13 . 
         FIG. 15  is a cross-sectional view illustrating a  1 XV- 1 XV cross section of the bumper and the shaft of  FIG. 13 . 
         FIG. 16  is a perspective view illustrating an extracorporeal fixing unit including a base end holding portion and a support portion for supporting the base end holding portion according to Modification Example 1-5. 
         FIG. 17A  is a plan view illustrating an extracorporeal fixing unit in an initial state. 
         FIG. 17B  is a plan view illustrating a state in which a restriction unit is removed from the extracorporeal fixing unit. 
         FIG. 17C  is a plan view illustrating a state in which the support portion is pushed in from both sides and the base end holding portion is pushed out from the extracorporeal fixing unit. 
         FIG. 18  is a perspective view illustrating an insertion jig set according to an embodiment of the present invention and illustrates a state in which a cap restrains the bumper so that the bumper is folded. 
         FIG. 19  is a partial cross-sectional view illustrating a portion of the insertion jig set and is a view illustrating a  2 II- 2 II cross section of  FIG. 18 . 
         FIG. 20  is a partial cross-sectional perspective view illustrating a cross section of a distal end portion of a mantle portion and is a view illustrating a  2 III- 2 III cross section of  FIG. 18 . 
         FIG. 21  is a perspective view illustrating the insertion jig set and illustrates a state in which the cap releases the bumper to expand the bumper. 
         FIG. 22  is a partial cross-sectional view illustrating a portion of the insertion jig set and is a view illustrating a  2 V- 2 V cross section in  FIG. 21 . 
         FIG. 23  is a cross-sectional view illustrating a locking structure between a mantle portion and a cap according to Modification Example 2-1 and illustrates a bent end portion in a closed arm state. 
         FIG. 24  is a cross-sectional view illustrating the locking structure between the mantle portion and the cap according to Modification Example 2-1 and is a view illustrating the bent end portion in an open arm state. 
         FIG. 25  is a cross-sectional view illustrating a locking structure between a gastrostomy catheter and a cap according to Modification Example 2-2. 
         FIG. 26  is a cross-sectional view illustrating a locking structure between a gastrostomy catheter and a cap according to Modification Example 2-3 and a view illustrating a locked state. 
         FIG. 27  is a cross-sectional view illustrating the locking structure between the gastrostomy catheter and the cap according to Modification Example 2-3 and is a view illustrating an unlocked state. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 
     The embodiment described below is merely an example for facilitating the understanding of the present invention, and does not limit the present invention. That is, a shape, dimension, arrangement, or the like of a member described below can be modified and improved within a scope which does not depart from the gist of the present invention, and the present invention includes equivalents thereof. 
     Moreover, in all the drawings, the same reference numerals are assigned to the same components, and repeated descriptions thereof will be appropriately omitted. 
     &lt;&lt;Overview&gt;&gt; 
     First, an overview of a gastrostomy catheter  11  according to the present embodiment will be described mainly with reference to  FIGS. 1 and 2 .  FIG. 1  is a front view of the gastrostomy catheter  11  according to the present embodiment, and  FIG. 2  is a front cross-sectional view of the gastrostomy catheter  11 . 
     In the present specification, a “distal side” refers to a side of the gastrostomy catheter  11  far from an operator of the gastrostomy catheter  11  unless otherwise specified, and specifically, refers to a side on which a bumper  13  is provided. Further, the distal side may be referred to as a tip side. 
     Moreover, a “proximal side” refers to a side of the gastrostomy catheter  11  close to the operator unless otherwise specified. In addition, the proximal side may be referred to as a base end side. 
     The gastrostomy catheter  11  includes a shaft  12  in which a lumen is provided, a flexible bumper  13  which is provided at a tip of the shaft  12 , and a linear member (wire  14 ) which has elasticity and can bias the bumper  13  in a diameter-increasing direction or can restrict deformation of the bumper  13  in a diameter-decreasing direction. 
     Here, “the bumper  13  can be biased in the diameter-increasing direction” means that the wire  14  is elastically deformed and comes into contact with the bumper  13  in a radial direction, and thus, it is possible to apply a restoring force in the diameter-increasing direction of the bumper  13 . 
     Further, “the deformation of the bumper  13  in the diameter-decreasing direction can be restricted” means that when the bumper  13  abuts on an edge surface of a stomach wall and a diameter of the bumper  13  decreases, the wire  14  abuts on the bumper  13 , and thus, the deformation of the bumper  13  in the diameter-decreasing direction can be restricted. That is, the wire  14  is not limited to a wire which constantly biases the bumper  13  in the diameter-increasing direction, and the wire  14  may be biased in the diameter-increasing direction for the first time when an external force is applied to the bumper  13 . 
     Moreover, in the present embodiment, the restoring force of the wire  14  is applied to the bumper  13  from the inside in the diameter-increasing direction. However, for example, the restoring force in the diameter-increasing direction may be applied from a linear member (no illustrated) disposed outside the bumper  13 . 
     The gastrostomy catheter  11  includes the wire  14  which can bias the bumper  13  in the diameter-increasing direction or restrict the deformation of the bumper  13  in the diameter-decreasing direction. Accordingly, as compared with a gastrostomy catheter  11  which does not have the wire  14 , it is possible to employ a material having flexibility for the bumper  13 . 
     Accordingly, a resistance applied to a body when the gastrostomy catheter  11  is inserted or removed can be suppressed low. In addition, the gastrostomy catheter  11  including the bumper  13  and the wire  14  does not use a fluid unlike the gastrostomy catheter including a balloon. Accordingly, there is no need to replace the fluid. Therefore, as compared with a case where a balloon is used, time and effort required for management can be reduced, and the gastrostomy catheter  11  can be placed for a relatively long time. 
     &lt;&lt;Structure of Gastrostomy Catheter&gt;&gt; 
     Next, details of a structure of the gastrostomy catheter  11  will be described mainly with reference to  FIGS. 3 to 5  in addition to  FIGS. 1 and 2 .  FIG. 3  is a bottom view of the bumper  13  when viewed in a direction of an arrow  1 III in  FIG. 1 ,  FIG. 4  is an explanatory view for explaining an angle of each site of a wire  14  with respect to an inner peripheral surface of the bumper  13 .  FIG. 5  is a schematic explanatory view illustrating a state of the gastrostomy catheter  11  in which the bumper  13  is placed in a stomach  152 . 
     The gastrostomy catheter  11  mainly includes the shaft  12 , a fixing portion (extracorporeal fixing unit  15 ) which is provided in a base end portion of the shaft  12 , the bumper  13  which is provided on a tip side of the gastrostomy catheter  11 , and the wire  14  which is disposed over the inside of each of the extracorporeal fixing unit  15 , the shaft  12 , and the bumper  13 . 
     The gastrostomy catheter  11  according to the present embodiment, except for the wire  14 , is integrally formed of silicone rubber or urethane rubber. However, the present invention is not limited to this configuration and a separate component may be joined to constitute the gastrostomy catheter  11 . In particular, even in a configuration in which a separate component is joined to constitute the gastrostomy catheter  11 , the same kind of material is preferable in terms of quality. 
     The extracorporeal fixing unit  15  and the shaft  12  include the lumen. The lumen includes a main lumen  18  for injecting a nutrient and a sub-lumen  19  which accommodates at least a portion (base end side) of the wire  14 . 
     The main lumen  18  communicates with a hollow space of the bumper  13  and a communication hole  13   a  to be described later which is formed in the bumper  13  and forms a flow path which penetrates from the base end portion to the tip portion in the gastrostomy catheter  11 . Accordingly, the nutrient can be injected into the stomach  152  from outside the body. The main lumen  18  is formed in a D-shaped cross section in the present embodiment, and linearly extends along an axial direction of the shaft  12  at centers of the shaft  12  and the extracorporeal fixing unit  15 . 
     In the hollow bumper  13 , a communication hole  13   a  which is a circular hole is formed at an end to which the main lumen  18  extends. The communication hole  13   a  is formed to have a large diameter so as to expose the main lumen  18  and the sub-lumen  19  and include the main lumen  18  and the sub-lumen  19  inside when viewed from a bottom of the bumper  13 . 
     The nutrient supplied into the stomach  152  (refer to  FIG. 5 ) via the gastrostomy catheter  11  passes through the extracorporeal fixing unit  15  and the main lumen  18  of the shaft  12  and is supplied into the stomach  152  through the communication hole  13   a  of the bumper  13 . A check valve for preventing backflow of a content such as gastric juice from the inside of the stomach  152  to the outside of the body is provided in the main lumen  18 . However, in a state in which the check valve is omitted,  FIG. 2  or the like is illustrated. 
     The sub-lumen  19  is formed on an outer peripheral side of the main lumen  18 . The main lumen  18  is formed in a D-shaped cross section in a site passing through the shaft  12 . Accordingly, the sub-lumen  19  is formed through a site formed thicker than other sites. The sub-lumen  19  is formed in a circular cross section and is bent in an L shape along the shaft  12  and the extracorporeal fixing unit  15 . Specifically, the sub-lumen  19  linearly extends along the axial direction in the shaft  12 , is bent at a right angle at a site reaching the extracorporeal fixing unit  15 , and linearly extends along the extension direction of the extracorporeal fixing unit  15 . Since a portion of the wire  14  is accommodated in the sub-lumen  19 , the injection of the nutrient through the main lumen  18  side is not hindered. Further, the wire  14  can be protected in the sub-lumen  19 . 
     In the sub-lumen  19 , a tip opening portion  19   b , which is a distal end portion having a certain length, extends linearly from the proximal side to the distal side and is continuous with the inside of the bumper  13 . Here, that the tip opening portion  19   b  of the sub-lumen  19  is continuous with the inside of the bumper  13  means that the tip opening portion  19   b  of the sub-lumen  19  is provided in a space continuous with a space inside the bumper  13 . In this way, the sub-lumen  19  is formed and a base end side of the wire  14  is disposed in the sub-lumen  19 . Accordingly, a tip side of the wire  14  can be guided into the bumper  13 . 
     The extracorporeal fixing unit  15  abuts on an abdominal wall  150 , and thus, fixes (restricts a movement to a predetermined position) the gastrostomy catheter  11  outside the body so that the gastrostomy catheter  11  is not embedded in a fistula  153 . The extracorporeal fixing unit  15  is formed larger than the shaft  12  in at least one direction perpendicular to the axial direction of the shaft  12  passing through the fistula  153 . The extracorporeal fixing unit  15  in the present embodiment has a small piece shape which extends linearly perpendicular to an axis of the shaft  12 . As illustrated in  FIG. 5 , the fistula  153  is formed to penetrate the abdominal wall  150  and the stomach wall  151 . 
     The extracorporeal fixing unit  15  according to the present embodiment is formed integrally with the shaft  12  and the bumper  13 . In the extracorporeal fixing unit  15 , an opening  18   a , which is a central portion of the shaft  12  in a radial direction and is a proximal opening of the main lumen  18  formed in the axial direction, is formed. Moreover, a strap  17  extends integrally from a side surface of the extracorporeal fixing unit  15 , and a cap  16  capable of sealing the opening  18   a  is formed at a tip portion of the strap  17 . 
     The extracorporeal fixing unit  15  includes a base end holding portion  15   c  described later which holds a base end portion  14   a  of the wire  14 . 
     The base end portion  14   a  of the wire  14  is embedded in the base end holding portion  15   c , and thus, the base end holding portion  15   c  holds the base end portion  14   a . In order to easily pull out the wire  14  from other sites in the gastrostomy catheter  11 , the base end holding portion  15   c  is provided in the extracorporeal fixing unit  15  so as to be cuttable. A configuration of the base end holding portion  15   c  which holds the base end portion  14   a  of the wire  14  is not limited to the configuration in which the base end portion  14   a  is embedded to hold the wire  14 . For example, in order to hold the wire  14 , a stopper or the like may be provided at the base end of the wire  14  so that a portion of the extracorporeal fixing unit  15  is locked to the stopper, or the base end portion  14   a  of the wire  14  may be interposed therebetween by a portion of the extracorporeal fixing unit  15 . 
     In particular, a linear marker  15   b  serving as a guide for a cutout portion is provided on a side surface of the extracorporeal fixing unit  15  according to the present embodiment. The marker  15   b  is attached to a position included in an imaginary plane (vertical surface in the present embodiment) intersecting a base end portion  19   a  of the sub-lumen  19 , which is a position where the base end holding portion  15   c  can be reliably cut off. Here, the base end portion  19   a  does not mean a base end surface, but means a site having a certain length at the base end. 
     The position at which the marker  15   b  is attached may be an upper surface (proximal end surface) of the extracorporeal fixing unit  15 . Moreover, the marker  15   b  may be formed of a paint, or may be simply a groove-shaped cut. Further, as long as the positions of the wire  14  and the sub-lumen  19  can be visually recognized, the marker  15   b  is not necessarily an essential component. 
     The base end holding portion  15   c  is provided in this manner, and thus, the wire  14  can be placed at a predetermined position at which the tip portion of the wire  14  is located in the bumper  13 . 
     For example, in the gastrostomy catheter  11  according to the present embodiment, a site disposed outside the body may be a so-called button type or a tube type. If there are other sites disposed outside the body, such as in a case of the tube type, the configuration of the gastrostomy catheter is not limited to a configuration in which the base end holding portion  15   c  is provided in the extracorporeal fixing unit  15 , and it is sufficient if there is a site which holds the base end portion  14   a  of the wire  14  on a proximal side from the distal end  15   a  of the extracorporeal fixing unit  15 . 
     If the base end holding portion  15   c  is not cut off, as in the base end holding portion  15   c  according to the above-described configuration, the wire  14  is prevented from coming off from the extracorporeal fixing unit  15  or the like. Accordingly, it is possible to prevent a patient from unexpectedly removing the wire  14 . 
     The bumper  13  is formed integrally with the shaft  12  and is formed in a hollow disk shape. The shape of the bumper  13  in the present embodiment is the same (including substantially the same) disk shape in appearance in a natural state and a state in which the tip side of the wire  14  is accommodated. However, the bumper  13  is not limited to this shape, and may have flexibility such that the bumper  13  expands radially outward only when the tip side of the wire  14  is accommodated. 
     Moreover, the bumper  13  is formed to have a thickness thinner than a thickness (strictly speaking, a distance between a wall surface of the main lumen  18  and an outer surface of the shaft  12  at a site where the sub-lumen  19  is not formed) of the shaft  12  so as to have a predetermined flexibility. In this way, since the bumper  13  is thinner than the shaft  12 , the bumper  13  can be easily expanded and shrunk. 
     As described above, the communication hole  13   a  which allows the inside and the outside of the bumper  13  to communicate with each other is formed on an extension side of the main lumen  18  on the distal side of the bumper  13 . 
     In the bumper  13 , the tip side of the wire  14  formed of a super-elastic alloy is disposed so as to be coiled. Accordingly, the bumper  13  is biased radially outward and a disk-shaped shape (including a shape of which a diameter is slightly reduced in the radial direction) is maintained in the stomach  152 . The present invention is not limited to the configuration in which the wire  14  constantly biases the bumper  13  radially outward. That is, a configuration may be adopted in which the bumper  13  is biased radially outward when an external force is applied to the bumper  13  so that the bumper  13  is deformed in the diameter-decreasing direction and the bumper  13  abuts on the wire  14 , and the deformation of the bumper  13  is restricted. 
     Furthermore, the present invention is not limited to the configuration in which the bumper  13  is formed in a disk shape in a natural state, and a configuration may be adopted in which the bumper  13  is formed in a disk shape for the first time when the tip side of the wire  14  is disposed in the bumper  13 . 
     A portion on at least the tip side of the linear member (wire  14 ) is disposed in the bumper  13 , and the linear member  14  is configured to be changed to a first state in which the linear member can bias the bumper  13  radially outward or can restrict the deformation of the bumper  13  in the diameter-decreasing direction, and a second state in which the linear member biases the bumper  13  radially outward lower than when the linear member is in the first state or does not bias the bumper  13 , or the linear member allows the deformation of the bumper  13  in the diameter-decreasing direction more than when the linear member is in the first state. The second state is a state in which the wire  14  is disposed closer to the base end side of the bumper  13  or the wire  14  is pulled out closer to a proximal side from the bumper  13  than when the wire  14  is in the first state. 
     Specifically, when the wire  14  is completely pulled out from the bumper  13  (pulled out closer to the proximal side from the bumper  13 ), the wire  14  naturally does not bias the bumper  13  at all. Meanwhile, when the wire  14  is partially pulled out from the bumper  13 , the bumper  13  is biased by a lower force than before the bumper  13  is pulled out, or the restricted deformation of the bumper  13  in the diameter-decreasing direction is allowed. The state of the bumper  13  relating to both of these is referred to as a “second state”. 
     In this way, a state in which the wire  14  restricts the deformation of the bumper  13  can be changed depending on the position of the wire  14  with respect to the bumper  13 . 
     The term “radially outward” means a direction having a radially outward component, and means all directions except a radially inward direction (in other words, a direction toward a center of the bumper  13 ). The same applies to the following. 
     As described above, the base end portion  14   a  of the wire  14  is embedded in the base end holding portion  15   c . At least the tip portion  14   b  of the wire  14  is movably disposed in the bumper  13  without being supported by other members, and can be inserted into or drawn from the inside and outside (more specifically, the inside of the bumper  13  and a distal side outer portion of the bumper  13 ) of the bumper  13  via the communication hole  13   a.    
     According to this configuration, it is possible to easily manufacture the gastrostomy catheter  11  which is disposed so that the tip portion  14   b  of the wire  14  is coiled in the bumper  13 . Specifically, first, a manufacturer once puts out the tip portion  14   b  of the wire  14  passing through the sub-lumen  19  from the communication hole  13   a  to the outside of the bumper  13 . Thereafter, a base end side rather than a tip side in the tip portion  14   b  of the wire  14  coming out from the bumper  13  is accommodated in the bumper  13  so as to be gradually coiled in the bumper  13 , and thus, the wire  14  is disposed in the bumper  13  until the tip thereof is in the bumper  13 . Accordingly, it possible to easily manufacture the gastrostomy catheter  11  having the wire  14  which is accommodated so that the tip side is coiled. 
     The above-described wire  14  is changed from the first state to be disposed on a proximal side in a direction pulled out from the bumper  13  to the second state, it is possible to weaken a biasing force to the bumper  13  or to allow the deformation of the bumper  13  in the diameter-decreasing direction. In this way, the wire  14  is set to the second state, and thus, a resistance applied to the body when the gastrostomy catheter  11  is removed can be suppressed low. 
     Moreover, in the present embodiment, as will be described later, the gastrostomy catheter  11  is inserted in a state in which the tip side of the wire  14  is accommodated in the bumper  13  and in a state in which the bumper  13  is folded by a capsule cover  110 . For example, when inserting the gastrostomy catheter  11  without using the capsule cover  110 , the wire  14  is pulled out from the bumper  13 , and after the bumper  13  is in the second state, the gastrostomy catheter  11  may be inserted. In this case as well, the resistance applied to the body can be suppressed low. 
     The present invention is not limited to the configuration in which the tip side of the coiled wire  14  has a curvature to constantly bias an inner surface of the bumper  13 . That is, the tip side of the coiled wire  14  may have a radius of curvature larger than an outer diameter of the shaft  12 , and may be disposed to be separated from the inner surface of the bumper  13  as long as the deformation of the bumper  13  is suppressed so that the bumper  13  can be locked to an edge of the fistula  153  in the stomach  152 . 
     In the above embodiment, the configuration in which the wire  14  is completely pulled out from the gastrostomy catheter  11  is described. However, the present invention is not limited to the configuration. For example, only a portion of the wire  14  may be pulled out from the bumper  13  to reduce an amount of a site of the wire  14  in the bumper  13 . Even in this case, the radially outward biasing force of the bumper  13  is weakened or the force for restricting the deformation of the bumper  13  in the diameter-decreasing direction is weakened by an amount corresponding to the reduction in the amount of the wire  14 . Accordingly, it is possible to suppress the resistance when the gastrostomy catheter  11  is inserted into or removed from the inside of the stomach  152 . The configuration is preferable in that a load of the wire  14  acting on the bumper  13  can be easily adjusted. 
     However, the present invention is not limited to this configuration, and is not limited to a configuration in which the wire  14  is pulled out to the proximal side of the gastrostomy catheter  11  as long as the load of the wire  14  on the bumper  13  can be adjusted. For example, a rod for hooking the wire  14  may be inserted from the main lumen  18 , and the wire  14  may be wound in the bumper  13  to reduce the diameter so that the radially outward load on the bumper  13  is reduced. 
     Further, at least the tip portion  14   b  of the wire  14  is covered with a coating portion  14   c  having a lower hardness than the wire  14 , or is formed into a blunt (substantially spherical shape) shape by electric discharge machining. 
     At least the tip portion  14   b  of the wire  14  is covered with a coating portion  14   c , or is formed into a blunt (substantially spherical shape) shape by electric discharge machining According to this configuration, it is possible to prevent the tip portion  14   b  from damaging the bumper  13  when the tip portion  14   b  of the wire  14  is accommodated in the bumper  13 . 
     In a state in which the wire  14  is disposed over the sub-lumen  19  and the bumper  13 , as illustrated in  FIG. 2 , a first site  14   x  of the wire  14  disposed in the sub-lumen  19  and a second site  14   y  disposed in the bumper  13  are bent at the bending point  14   j  and are formed continuously. In other words, the wire  14  is bent in the bumper  13  outward at the bending point  14   j  in the radial direction of the bumper  13 . 
     As described above, since the wire  14  is bent, it is easy to smoothly bias the bumper  13  in the diameter-increasing direction or to uniformly restrict the deformation of the bumper  13  in the diameter-decreasing direction at the end of the wire  14  inserted into the sub-lumen  19 . Accordingly, it is possible to suitably maintain a state in which the bumper  13  is biased in the diameter-increasing direction and a state in which the deformation of the bumper  13  in the diameter-decreasing direction is restricted.  153 , and it is possible to prevent the bumper  13  and the gastrostomy catheter  11  from being unexpectedly pulled out from the fistula  153 . 
     Further, in the state in which the wire  14  is disposed over the sub-lumen  19  and the bumper  13 , at least a portion of the site of the wire  14  disposed in the bumper  13  is formed so as to be bent at a bending point  14   k  to extend in a direction along an inner peripheral surface of the bumper  13 . 
     Here, as illustrated in  FIG. 4 , when an angle between an extension line of a certain portion of the wire  14  and a normal line to the inner peripheral surface of the bumper  13  is represented by an incident angle  1 α, the angle of incidence with respect to an extension line from the bending point  14   j  toward the inner peripheral surface of the bumper  13  is defined  1 α 1 , and the angle of incidence with respect to the extension line from the bending point  14   k  toward the inner peripheral surface of the bumper  13  is defined as  1 α 2 . In this case, that the wire  14  is bent so as to extend in the direction along the inner peripheral surface of the bumper  13  means that the wire  14  is bent so that the incident angle  1 α 2  is larger than the incident angle  1 α 1 . 
     Since the wire  14  is formed to be bent in the direction along the inner peripheral surface of the bumper  13 , the wire  14  can be led along the inner peripheral surface of the bumper  13 , and at each position in a circumferential direction of the bumper  13 , it is easy to uniformly apply a load which biases the bumper  13  in the diameter-increasing direction or a load which restricts the deformation of the bumper  13 . 
     &lt;&lt;Method of Attaching Gastrostomy Catheter&gt;&gt; 
     Next, a method of attaching the gastrostomy catheter  11  will be described with reference to  FIGS. 6 and 7  in addition to  FIG. 5 .  FIG. 6  is a schematic explanatory view illustrating a state in which the gastrostomy catheter  11  is inserted into the stomach  152  through the fistula  153 , and  FIG. 7  is a schematic explanatory view illustrating a state in which the capsule cover  110  is removed from the gastrostomy catheter  11  by an insertion jig  111  and the bumper  13  is expanded. 
     The gastrostomy catheter  11  includes the cover (capsule cover  110 ) which holds and accommodates the bumper  13  in a state in which the tip side of the wire  14  is disposed in the bumper  13  and is folded. Here, the capsule cover  110  can be directly or indirectly attached to the shaft  12  and may be any one as long as it holds the folded state of the bumper  13  and accommodates the bumper  13 . In other words, the term “accommodation” includes accommodation of the entirety of the bumper  13  and accommodation of at least a portion of the bumper  13 . 
     When the bumper  13  is disposed in the stomach  152  via the fistula  153 , the capsule cover  110  suppresses the resistance applied to the wall surface of the fistula  153  while maintaining the folded state of the bumper  13  and facilitates insertion of the bumper  13  into the body. 
     The capsule cover  110  is a hard capsule cover used for food made of a cellulose-based material or a gelatin-based material, or is a material decomposed in the body such as polylactic acid, and is formed in a blunt cap shape in which one side has a bottom portion and the other side is an open end. The shape of the capsule cover  110  is not particularly limited, and may be a hemisphere or the like. 
     The surgeon removes the capsule cover  110  in the body, and thus, can increases the diameter of the bumper  13  by biasing of the wire  14  in the diameter-increasing direction. The insertion jig  111  is used to attach the gastrostomy catheter  11  to the fistula  153  and remove the capsule cover  110 . 
     The insertion jig  111  includes a main body tube  111   a , a pair of claws  111   b  which is attached to the main body tube  111   a , an operation unit  111   c , a piston  111   d  which is reciprocally movable with respect to the main body tube  111   a , and an extrusion rod  111   e  which is connected to the piston  111   d  and protrudes/retreats in an axial direction. 
     When the gastrostomy catheter  11  is inserted into the fistula  153 , the surgeon folds the bumper  13  and covers the folded bumper  13  with the capsule cover  110 , and thus, maintains the folded state of the bumper  13 . 
     Further, the surgeon grasps the insertion jig  111 , supports a lower surface (distal surface) of the extracorporeal fixing unit  15  of the gastrostomy catheter  11  so that the shaft  12  is interposed between the pair of claws  111   b , and maintains the insertion jig  111  as illustrated in  FIG. 6 . 
     Next, the surgeon causes the bumper  13  covered with the capsule cover  110  to pass through the fistula  153  together with the capsule cover  110 , and pushes the gastrostomy catheter  11  in the stomach  152  by the insertion jig  111  to a position (a position where the claw  111   b  abuts on a surface of the abdominal wall  150 ) at which the bumper  13  reaches the inside of the stomach  152 . 
     Thereafter, as illustrated in  FIG. 7 , the surgeon operates to push the operation unit  111   c  to the distal side and pushes the piston  111   d  into the main body tube  111   a  so that the extrusion rod  111   e  protrudes. In this case, the extrusion rod  111   e  pushes out only the capsule cover  110  through the communication hole  13   a  of the bumper  13 , and the capsule cover  110  falls out of the bumper  13 , as illustrated in  FIG. 7 . 
     The diameter of the bumper  13  released from the holding from the capsule cover  110  increases to have a diameter larger than a diameter of the fistula  153  by the biasing force of the wire  14 , and the bumper  13  is placed in the stomach  152 . 
     Since the capsule cover  110  which has fallen into the stomach  152  is a material which is edible or decomposed in the body as described above, the capsule cover  110  is excreted or dissolved together with the content of the stomach and has no effect on the body. 
     &lt;&lt;Method of Removing Gastrostomy Catheter&gt;&gt; 
     The surgeon needs to replace the gastrostomy catheter  11  every predetermined period in order to suitably maintain a sanitary condition when the surgeon uses the gastrostomy catheter  11 . A method of removing the existing gastrostomy catheter  11  required when the gastrostomy catheter  11  is replaced will be described with reference to  FIGS. 8 and 9 .  FIG. 8  is a schematic explanatory view illustrating a state of the gastrostomy catheter  11  in a state in which the base end holding portion  15   c  is removed from the extracorporeal fixing unit  15 .  FIG. 9  is a schematic explanatory view illustrating a state in which the gastrostomy catheter  11  is removed from the inside of the stomach  152 . 
     First, the surgeon removes the base end holding portion  15   c  of the extracorporeal fixing unit  15  from other sites of the extracorporeal fixing unit  15  using scissors or the like so that the base end holding portion  15   c  is cut along the marker  15   b . In this case, the surgeon separates the base end holding portion  15   c  from other sites of the extracorporeal fixing unit  15  so as not to cut the wire  14 . As described above, since the marker  15   b  is attached at the position included in the imaginary plane intersecting the base end portion  19   a  of the sub-lumen  19 , by separating the base end holding portion  15   c  along the marker  15   b , the embedded portion of the base end portion  14   a  of the wire  14  in the extracorporeal fixing unit  15  is eliminated. 
     The surgeon grasps the base end portion  14   a  and pulls out the wire  14  from the bumper  13 , the shaft  12 , and the extracorporeal fixing unit  15 . 
     Finally, the surgeon grasps the extracorporeal fixing unit  15  and pulls the gastrostomy catheter  11  out of the body through the fistula  153 . In this case, as illustrated in  FIG. 9 , the bumper  13  is in the second state due to the wire  14  being pulled out and the diameter of the bumper  13  decreases when the bumper  13  comes into contact with the wall surface of the fistula  153 . Accordingly, the resistance to the body is suppressed low. 
     Modification Example 1-1 
     In the above embodiment, as illustrated in  FIG. 2 , the base end holding portion  15   c  for holding the base end portion  14   a  of the wire  14  is formed integrally with the extracorporeal fixing unit  15 , the wire  14  is embedded to be held and is cut to release the holding of the wire  14 . However, the present invention is not limited to this configuration. 
     Next, an extracorporeal fixing unit  115  according to Modification Example 1-1 will be described with reference to  FIG. 10 .  FIG. 10  is a front cross-sectional view illustrating an extracorporeal fixing unit  115  according to Modification Example 1-1. 
     The base end holding portion  115   a  which holds the base end portion  14   a  of the wire  14  is separate from the fixing portion (extracorporeal fixing unit  115 ) and is detachably attached to the fixing portion (extracorporeal fixing unit  115 ). 
     Specifically, the base end holding portion  115   a  is disposed on an extension of the base end portion  19   a  of the sub-lumen  19 , has a small-diameter neck portion and a large-diameter head portion, and has a locking protrusion  115   b  protruding downward (distal side) at a lower portion thereof. A concave groove  115   c  having a shape relative to the locking protrusion  115   b  is formed in a site of the extracorporeal fixing unit  115  facing the locking protrusion  115   b.    
     The locking protrusion  115   b  is accommodated in the groove  115   c  to be locked by an opening forming the concave groove  115   c  being expanded so as to be elastically deformed. 
     According to this configuration, a state in which the tip portion of the wire  14  is disposed in the bumper  13  can be maintained by attaching the base end holding portion  115   a  to the extracorporeal fixing unit  115 . In addition, by releasing the locking of the locking protrusion  115   b  into the concave groove  115   c  and removing the base end holding portion  115   a  from the extracorporeal fixing unit  115 , the wire  14  together with the base end holding portion  115   a  can be removed from the shaft  12 , the bumper  13 , and the extracorporeal fixing unit  115 . 
     The locking protrusion  115   b  may be made of a resin rubber harder than the concave groove  115   c . According to this configuration, the locking protrusion  115   b  is easily fitted into the relatively soft concave groove  115   c . A configuration in which a concave groove is provided on the base end holding portion  115   a  side and a locking protrusion is provided on the extracorporeal fixing unit  115  side may be adopted. 
     In order to prevent the patient from accidentally detaching the base end holding portion  115   a  from the extracorporeal fixing unit  115 , a clip (not illustrated) or the like which is interposed between the base end holding portion  115   a  and the extracorporeal fixing unit  115  may be further provided. 
     Modification Example 1-2 
     In the above embodiment, as illustrated in  FIG. 3 , the configuration is described, in which the communication hole  13   a  is formed in the bumper  13  to have a large diameter so as to expose the main lumen  18  and the sub-lumen  19 . However, the present invention is not limited to this configuration. 
     Next, a bumper  113  according to Modification Example 1-2 will be described with reference to  FIG. 11 .  FIG. 11  is a bottom view illustrating a communication hole  113   a  of the bumper  113  according to Modification Example 1-2. 
     A portion of an inner wall of the bumper  113  according to the Modification Example 1-2 is located on the extension of the sub-lumen  19 . Specifically, the communication hole  113   a  in the present example is formed in a D-shaped cross section so as not to expose the sub-lumen  19  while exposing the main lumen  18  with an edge when viewed from the bottom. 
     According to this configuration, when the wire  14  is inserted into the sub-lumen  19  and the tip portion  14   b  is disposed in the bumper  113 , the tip portion  14   b  abuts on a portion of the inner wall of the bumper  113 . Therefore, the tip side of the wire  14  is naturally disposed in the radial direction of the bumper  113 . 
     In particular, in a second state in which the tip side of the wire  14  is not disposed in the bumper  113 , the bumper  113  can be disposed in the stomach  152  through the fistula  153  while suppressing the resistance applied to the body. 
     Thereafter, the tip side of the wire  14  having the base end portion  14   a  embedded in the base end holding portion  115   a  illustrated in  FIG. 10  is fed through the sub-lumen  19  so as to be coiled in the bumper  113 . Accordingly, the state in which the bumper  113  can be biased in the diameter-increasing direction or the state in which the deformation of the bumper  113  in the diameter-decreasing direction can be restricted can be easily achieved. Therefore, the bumper  113  can be brought into the first state by a simple method of inserting the wire  14  into the sub-lumen  19 , instead of a method of expanding the diameter of the bumper  13  by removing the capsule cover  110  by the insertion jig  111 . 
     The configuration is described in which the main lumen  18  in the above embodiment and the present example has a D-shaped cross section. However, as long as a thickness for forming the sub-lumen  19  can be secured in the shaft  12 , the main lumen  18  may have a circular cross-section or a rectangular cross and is not limited to such a shape. Accordingly, as long as a portion of the inner wall of the bumper  113  can be located on the extension of the sub-lumen  19 , the shape of the communication hole  113   a  may be a circular cross section or rectangular cross section and is not limited to such a shape. 
     Modification Example 1-3 
     In the above embodiment, as illustrated in  FIG. 2 , the configuration is described in which the tip opening portion  19   b  of the sub-lumen  19  extends linearly from the proximal side to the distal side and is continuous into the bumper  13 . However, the present invention is not limited to this configuration. 
     Next, a sub-lumen  129  according to Modification Example 1-3 will be described with reference to  FIG. 12 .  FIG. 12  is a front cross-sectional view illustrating a tip opening portion  129   b  of the sub-lumen  129  according to Modification Example 1-3. 
     A tip portion (the tip opening portion  129   b ) of the sub-lumen  129  passing through a shaft  122  according to Modification Example 1-3 is formed to be bent radially outward of the bumper  13 . Specifically, the tip opening portion  129   b  extends to the inside of the bumper  13 , and a wall portion defining the tip opening portion  129   b  is bent and extends radially outward of the bumper  13  in the bumper  13 . 
     According to this configuration, when the wire  14  is inserted into the sub-lumen  129  and the tip portion  14   b  is disposed in the bumper  13 , the tip portion  14   b  is guided radially outward of the bumper  13  by the tip opening portion  129   b  of the sub-lumen  129 . Therefore, the tip side of the wire  14  is naturally disposed radially outward of the bumper  13 . 
     In particular, similar to the Modification Example 1-2, the tip side of the wire  14  is brought into the second state in which the tip side is not disposed in the bumper  13 , and thus, the bumper  13  can be disposed in the stomach  152  through the fistula  153  and the stomach  152  is inserted while the resistance applied to the body is suppressed. 
     Thereafter, the tip side of the wire  14  having the base end portion  14   a  embedded in the base end holding portion  115   a  illustrated in  FIG. 10  is fed through the sub-lumen  129  so as to be coiled in the bumper  13 . Accordingly, the first state (that is, the state in which the bumper  13  can be biased in the diameter-increasing direction or the state in which the deformation of the bumper  113  in the diameter-decreasing direction can be suppressed) can be easily achieved. Therefore, the bumper  13  can be brought into the first state by a simple method of inserting the wire  14  into the sub-lumen  19 , instead of expanding the bumper  13  by removing the capsule cover  110  by the insertion jig  111 . 
     Modification Example 1-4 
     The configuration is described in which each of the bumpers  13  and  113  according to the above embodiment is formed in a hollow disk shape. However, the present invention is not limited to this configuration. 
     Next, a bumper  133  and a shaft  132  to which the bumper  133  is attached according to Modification Example 1-4 will be described mainly with reference to  FIGS. 13 to 15 .  FIG. 13  is a perspective view illustrating the bumper  133  and the shaft  132  to which the bumper  133  is attached according to Modification Example 1-4,  FIG. 14  is a perspective view illustrating an inner layer  134  of the bumper  133  by removing an outer layer  135  of the bumper  133  and corresponds to  FIG. 13 .  FIG. 15  is a cross-sectional view illustrating a  1 XV- 1 XV cross section of the bumper  133  and the shaft  132  of  FIG. 13 . 
     The bumper  133  according to the present embodiment is formed in a star shape when viewed from an axial direction of the bumper  133  and is connected to a tip portion of the shaft  132 . 
     The shaft  132  has a shaft main body  132   a  and a tip portion (a first tip portion  132   b  and a second tip portion  132   c  illustrated in  FIG. 15 ) which is formed to have a diameter smaller than those of other sites (the shaft main body  132   a ). The bumper  133 , which will be described in detail later, extends from the tip portion of the shaft  132 . 
     The first tip portion  132   b  is formed continuously from the shaft main body  132   a  to the tip side and has a diameter smaller than that of the shaft main body  132   a . The second tip portion  132   c  is formed continuously from the first tip portion  132   b  to the tip side and has a diameter smaller than that of the first tip portion  132   b.    
     A connection tubular portion  134   a  of the inner layer  134  of the bumper  133 , which will be described later, is connected to the tip portion (second tip portion  132   c ) of the shaft  132 , and the inner layer  134  extends. In addition, a connection tubular portion  135   a  of the outer layer  135  of the bumper  133 , which will be described later, is connected to the tip portion (first tip portion  132   b ) of the shaft  132 , and the outer layer  135  extends. 
     According to the above configuration, a maximum deformation amount of the bumper  133  in the diameter-increasing direction connected to the first tip portion  132   b  of the shaft  132  can be made larger than a case where the tip portion (first tip portion  132   b ) of the shaft  132  is formed in the same diameter as that of the shaft main body  132   a.    
     That is, as described later, the inclination of the bumper  133  (an inclined portion  135   c  thereof) after the deformation in the axial direction can be increased by the wire  14  (refer to  FIG. 15 ) partially provided in the bumper  133 . Therefore, a contact area between the deformed bumper  133  and the inner surface of the stomach wall  151  (refer to  FIG. 5 ) can increase, and the bumper  133  can be easily placed in the stomach  152 . 
     As illustrated in  FIG. 15 , the bumper  133  includes the inner layer  134  and the outer layer  135 , a space  133   s  is provided between the inner layer  134  and the outer layer  135 , and a portion on the tip side of the linear member (wire  14 ) is disposed in the space  133   s.    
     In addition, as illustrated in  FIG. 15 , the shaft  132  includes one sub-lumen  132   d  described later through which the wire  14  passes and which extends in parallel with the axial direction. The sub-lumen  132   d  penetrates a tip surface of the first tip portion  132   b  and communicates with the space  133   s  between the inner layer  134  and the outer layer  135  of the bumper  133  attached to the tip portion of the shaft  132 . 
     According to this configuration, the space  133   s  accommodating a portion of the wire  14  can be formed between the inner layer  134  and the outer layer  135 . Further, since the space  133   s  is formed and a rigidity is reduced, when the wire  14  is pulled out from the bumper  133 , the bumper  133  can be smoothly deformed into a folded state. 
     On a surface of the outer layer  135  of the bumper  133 , a plurality of concave portions  135   f  which are depressed in the radial direction of the bumper  133  and extend along the axial direction of the bumper  133  are formed in a circumferential direction of the bumper  133 . 
     As described above, since the concave portions  135   f  are formed on the surface of (the outer layer  135  of) the bumper  133 , the bumper  133  can be smoothly deformed into a folded state. Specifically, when the bumper  133  is folded, a load applied from the wall of the fistula  153  (refer to  FIG. 5 ) is locally applied to a portion other than the concave portions  135   f  of the bumper  133 , and a starting point of the folding occurs in the concave portions  135   f . Since the concave portions  135   f  are a space for the folding, the bumper  133  can be smoothly deformed into a folded state. 
     The outer layer  135  of the bumper  133  includes, from a base end side to a tip side thereof, the connection tubular portion  135   a  which is connected to the shaft  132 , a large diameter portion  135   b  which has a maximum diameter portion  135   e , and a small diameter portion  135   g  which is provided on a tip side from the large diameter portion  135   b.    
     The inner layer  134  of the bumper  133  includes, from a base end side to a tip side thereof, the connection tubular portion  134   a  which is connected to the shaft  132 , an inclined portion  134   b  which extends to be inclined in a diameter-increasing direction from a tip of the connection tubular portion  134   a  to a base end of a tip portion  134   d , and the tip portion  134   d  which is provided on a tip side from the inclined portion  134   b.    
     The connection tubular portion  135   a  is connected to the first tip portion  132   b  of the shaft  132 , and an inner diameter of the connection tubular portion  135   a  is substantially equal to an outer diameter of the first tip portion  132   b.    
     The large diameter portion  135   b  has the inclined portion  135   c  which is inclined so as to increase in diameter toward the tip in a direction parallel to a axial direction of the shaft  132  including the maximum diameter portion  135   e , the maximum diameter portion  135   e , and an inclined portion  135   d  which is inclined so as to decrease in diameter toward the tip. 
     As illustrated in  FIG. 15 , the tip portion  14   b  of the wire  14  is accommodated in a plane space perpendicular to the axial direction of the bumper  133  including the maximum diameter portion  135   e . As described above, since the inclined portion  135   c  and the inclined portion  135   d  are formed on both sides of the maximum diameter portion  135   e , when the tip portion  14   b  of the wire  14  inserted into the space  133   s  is elastically restored in the radial direction, the tip portion  14   b  is suitably guided in the above plane space including the maximum diameter portion  135   e.    
     The maximum diameter portion  135   e  of the outer layer  135  of the bumper  133  is formed at a position separated from the tip of the shaft  132  toward the tip side. 
     As described above, since the maximum diameter portion  135   e  is formed at the position separated from the tip of the shaft  132  toward the tip side, the bumper  133  is prevented from covering and overlapping the shaft  132  when the maximum diameter portion  135   e  is contracted, and thus, the folded shape of the bumper  133  can be made compact. 
     The plurality of concave portions  135   f  are formed in the large diameter portion  135   b  of the outer layer  135  in the circumferential direction, and a plurality of concave portions  135   h  are formed in the small diameter portion  135   g  in the circumferential direction. The concave portions  135   f  and  135   h  in the large diameter portion  135   b  and the small diameter portion  135   g  are formed at corresponding positions in the circumferential direction of the bumper  133 . 
     Since the plurality of concave portions  135   f  and  135   h  formed in the large diameter portion  135   b  and the small diameter portion  135   g  are formed at the corresponding positions in the circumferential direction, sites of starting points at which the large diameter portion  135   b  and the small diameter portion  135   g  are folded become linear over the large diameter portion  135   b  and the small diameter portion  135   g . Therefore, the outer layer  135  of the bumper  133  can be smoothly deformed into a folded state. 
     The “corresponding position in the circumferential direction” specifically means that the positions are located at the same angle about the axis of the bumper  133  when the bumper  133  is viewed from the axial direction. 
     Similarly, a plurality of concave portions  134   c  are formed in the inclined portion  134   b  of the inner layer  134  in the circumferential direction, and a plurality of concave portions  134   e  are formed in the tip portion  134   d  in the circumferential direction. The concave portions  134   c  and  134   e  in the inclined portion  134   b  and the tip portion  134   d  are formed at corresponding positions in the circumferential direction of the bumper  133 . 
     Since the plurality of concave portions  134   c  and  134   e  formed in the inclined portion  134   b  and the tip portion  134   d  are formed at corresponding positions in the circumferential direction, sites of starting points at which the inclined portion  134   b  and the tip portion  134   d  are folded become linear over the inclined portion  134   b  and the tip portion  134   d . Therefore, the inner layer  134  of the bumper  133  can be smoothly deformed into the folded state. 
     Further, in the present embodiment, the concave portions  135   f  of the outer layer  135  and the concave portions  134   c  of the inner layer  134 , and the concave portions  135   h  of the outer layer  135  and the concave portions  134   e  of the inner layer  134  are provided at positions overlapping in the radial direction of the bumper  133 . In other words, a straight line which connects the most depressed sites of the concave portions  135   f  and  134   c  and the concave portions  135   h  and  134   e  and extends in the radial direction of the bumper  133  has a positional relationship intersecting with the axis of the bumper  133 . 
     According to this configuration, an interference between the inner layer  134  and the outer layer  135  is suppressed, and the bumper  133  can be smoothly deformed into the folded state. 
     In the large diameter portion  135   b , the inner layer  134  and the outer layer  135  are separated from each other, and in the small diameter portion  135   g , the inner layer  134  (strictly, the tip portion  134   d ) is in contact with the outer layer  135 . 
     According to the above configuration, since the inner layer  134  and the outer layer  135  are separated from each other in the large diameter portion  135   b , rigidity is reduced, and thus, the contraction is easily performed. Further, since the inner layer  134  and the outer layer  135  are in contact with each other at the small diameter portion  135   g , the rigidity can increase, and thus, excellent shape retention can be obtained. 
     Modification Example 1-5 
     In the embodiment illustrated in  FIG. 8 , when the wire  14  is removed from the bumper  13  in the case where the bumper  13  of the gastrostomy catheter  11  is removed from inside the stomach, the base end holding portion  15   c  is cut off from the extracorporeal fixing unit  15 . Further, in the embodiment illustrated in  FIG. 10 , the base end holding portion  115   a  is removed from the extracorporeal fixing unit  15  by releasing the locking of the locking protrusion  115   b  to the concave groove  115   c . However, the present invention is not limited to this configuration. 
     Next, an extracorporeal fixing unit  145  according to Modification Example 1-5 will be described mainly with reference to  FIGS. 16 and 17 .  FIG. 16  is a perspective view illustrating an extracorporeal fixing unit  145  including a base end holding portion  148  and a support portion  146  for supporting the base end holding portion  148  according to Modification Example 1-5.  FIG. 17A  is a plan view illustrating the extracorporeal fixing unit  145  in an initial state,  FIG. 17B  is a plan view illustrating a state in which a restriction piece  147  is removed from the extracorporeal fixing unit  145 , and  FIG. 17C  is a plan view illustrating a state in which the support portion  146  is pushed in from both sides and the base end holding portion  148  is pushed out from the extracorporeal fixing unit  145 . In  FIGS. 16 and 17 , the cap  16  and the strap  17  illustrated in  FIG. 1  is not illustrated. 
     A fixing portion (extracorporeal fixing unit  145 ) according to Modification Example 1-5 has the support portion  146  which movably supports the base end holding portion  148 , and the restriction unit (restriction unit  147 ) which restricts a movement of the base end holding portion  148  and detachment thereof from the support portion  146 . 
     The base end holding portion  148  according to the present embodiment is a plate piece having a trapezoidal thickness in a plan view, and the base end portion of the wire  14  is embedded inside the base end holding portion  148 . The base end holding portion  148  has an inverted tapered portion  148   a  formed so as to expand toward the outside of the fixing portion (extracorporeal fixing unit  145 ). 
     The support portion  146  includes a bottom wall  146   c  which supports the base end holding portion  148  from below, and connection walls  146   b  which are provided on both sides of the bottom wall  146   c  and stand uprightly. The bottom wall  146   c  and the connection wall  146   b  protrude outward from the other sites of the support portion  146  in an extension direction of the extracorporeal fixing unit  145 . 
     In the support portion  146 , a trapezoidal opening  146   d  in a plan view, which exposes at least a portion of the base end holding portion  148 , is formed on a proximal side of the support portion  146 . Since the opening  146   d  is formed in this manner, the surgeon can touch the base end holding portion  148  with a finger and separate the base end holding portion  148  from the extracorporeal fixing unit  145 , in addition to picking the support portion  146  from both sides as described later. 
     The restriction piece  147  is connected to the connection walls  146   b  and the bottom wall  146   c  of the support portion  146 , and is provided in a size and a position overlapping in a thickness direction with respect to the base end holding portion  148  in a direction in which the base end holding portion  148  is detached from the support portion  146 . 
     As illustrated in  FIG. 17B , the base end holding portion  148  is configured to be separable from the support portion  146  by separating the restriction piece  147  from the support portion  146 . 
     The extracorporeal fixing unit  145  has the support portion  146  and the restriction piece  147 . Accordingly, as compared with a case where the entire base end holding portion  148  is connected to the extracorporeal fixing unit  145 , the base end holding portion  148  can be easily separated from the support portion  146  only by separating the restriction piece  147  from the support portion  146 . 
     In the present embodiment, as the configuration in which the base end holding portion  148  can be separated, the support portion  146  is not provided on a path where the base end holding portion  148  is projected on the restriction piece  147 , and a through hole  146   e  illustrated in  FIG. 17A  and  FIG. 17B  is formed. According to this configuration, the movement of the base end holding portion  148  in the direction toward the restriction piece  147  is not restricted by the support portion  146 , and the movement is restricted only by the restriction piece  147 . 
     The support portion  146  has a facing portion  146   a  which extends along the inverted tapered portion  148   a  of the base end holding portion  148  in a state in which the support portion  146  is attached to the extracorporeal fixing unit  145 . The support portion  146  is configured to be deformable so that the facing portion  146   a  abuts on the inverted tapered portion  148   a  and the base end holding portion  148  can be pushed into the outside of the fixing portion (extracorporeal fixing unit  145 ) after the restriction piece  147  is separated from the support portion  146 . 
     According to this configuration, as illustrated in  FIG. 17C , the surgeon grasps the support portion  146  from both sides in a direction (in directions of thick arrows) sandwiching the base end holding portion  148 , and deforms the facing portion  146   a  of the support portion  146 . Then, a component force (in directions of thin arrows) of the load applied to the inverted tapered portion  148   a  from the facing portion  146   a  toward the outside in the extension direction of the extracorporeal fixing unit  145  is generated, and thus, the base end holding portion  148  is easily removed from the support portion  146  to the outside of the extracorporeal fixing unit  145 . 
     The “outside of the extracorporeal fixing unit  145 ” is not limited to a direction away from the shaft  12  (refer to  FIG. 16 ) in the extension direction of the extracorporeal fixing unit  145 , but may be a direction outward from a center of a thickness of the extracorporeal fixing unit  145  in direction intersecting the extension direction of the extracorporeal fixing unit  145 . The term “deformable” is a concept including elastic deformation and plastic deformation. 
     The shape of the base end holding portion  148  is not limited to a trapezoidal shape including the inverted tapered portion  148   a  in a plan view, and for example, may be formed in a pair of arcs instead of the linear inverted tapered portion  148   a . That is, the shape of the base end holding portion  148  may be a shape which is enlarged (in the direction in which the base end holding portion  148  is taken out) toward the outside of the extracorporeal fixing unit  145 . 
     &lt;&lt;Overview&gt;&gt; 
     First, an outline of each of an insertion jig set  2 S and an insertion jig (obturator  21 ) according to the present embodiment will be described with reference to  FIGS. 18 to 22 .  FIG. 18  is a perspective view illustrating the insertion jig set  2 S according to an embodiment of the present invention and illustrates a state in which a cap  25  restrains a bumper  24   a  so that the bumper  24   a  is folded, and  FIG. 19  is a partial cross-sectional view illustrating a portion of the insertion jig set  2 S and is a view illustrating a  2 II- 2 II cross section of  FIG. 18 .  FIG. 20  is a partial cross-sectional perspective view illustrating a cross section of a distal end portion of a mantle portion  22  and is a view illustrating a  2 III- 2 III cross section of  FIG. 18 .  FIG. 21  is a perspective view illustrating the insertion jig set  2 S and illustrates a state in which the cap  25  releases the bumper  24   a  to expand the bumper.  FIG. 22  is a partial cross-sectional view illustrating a portion of the insertion jig set  2 S and is a view illustrating a  2 V- 2 V cross section in  FIG. 21 . 
     In the present specification, a “distal side” refers to a side of the insertion jig set  2 S and the obturator  21  far from an operator of the insertion jig set  2 S and the obturator  21 , unless otherwise specified, and specifically, refers to a side attached to the cap  25  or covered with the cap  25 . Further, the distal side may be referred to as a tip side. 
     Moreover, a “proximal side” refers to a side of the insertion jig set  2 S and the obturator  21  closer to the operator unless otherwise specified. In addition, the proximal side may be referred to as a base end side. 
     Moreover, components of the insertion jig set  2 S moving to the distal side may be referred to moving forward, and the components moving to the proximal side may be referred to moving rearward. 
     The insertion jig set  2 S according to the embodiment of the present invention is an insertion jig set  2 S for inserting a gastrostomy catheter  24  having a foldable gastrointestinal fixing portion (bumper  24   a ) at a tip into a body (into the stomach). 
     The insertion jig set  2 S includes the insertion jig (obturator  21 ) configured to include the tubular mantle portion  22  and an inner insertion portion  23  which is movable forward and rearward through the mantle portion  22 , the gastrostomy catheter  24  which is attached around the mantle portion  22 , and the cap  25  which is disposed on a tip side of the mantle portion  22  and covers at least a portion of the folded gastrointestinal fixing portion (bumper  24   a ). 
     One of the gastrostomy catheter  24  or the mantle portion  22  and the cap  25  has a locking portion (locking claw  22   b ) which is locked to the other, and when the inner insertion portion  23  moves forward through the mantle portion  22 , the locking by the locking claw  22   b  is released. 
     According to the above configuration, the gastrostomy catheter  24  or the mantle portion  22  and the cap  25  are locked to each other, and the locking can be released by the inner insertion portion  23 . Accordingly, the cap  25  can be prevented from being unexpectedly detached from the gastrostomy catheter  24  and the mantle portion  22 . 
     In the present invention, the term “lock” refers to a state in which movement is restricted by being temporarily held and fixed, and in addition to a structurally locked state described below, includes a state of being physically adhered with an adhesive or the like so as to be detachable. 
     As a configuration for releasing the locking by the locking portion when the inner insertion portion  23  moves forward through the mantle portion  22 , there is a configuration in which the inner insertion portion  23  moving forward directly or indirectly abuts on a member including the locking portion, a locking force of the locking portion is weakened by deforming the member, and the locking is released. 
     In addition, there is a configuration in which the inner insertion portion  23  moving forward directly or indirectly abuts on the member including the locking portion or a member to be locked and presses the member, and the locking by the locking portion is released by applying a load stronger than the locking force by the locking portion between the locking portion and the member having the locking or the member to be locked. Details of these will be described later. 
     The insertion jig (obturator  21 ) according to the embodiment of the present invention inserts the gastrostomy catheter  24  having a foldable gastrointestinal fixing portion (bumper  24   a ) at the tip and the cap  25  covering at least a portion of the folded gastrointestinal fixing portion into the body. 
     The insertion jig (obturator  21 ) is configured to include the tubular mantle portion  22  around which the gastrostomy catheter  24  can be attached, and an inner insertion portion  23  which passes through the mantle portion  22 . The mantle portion  22  has the locking portion (locking claw  22   b ) which is locked to the cap  25 . 
     The inner insertion portion  23  releases the locking by the locking claw  22   b  when the inner insertion portion  23  moves forward through the mantle portion  22 . 
     According to the above configuration, the mantle portion  22  and the cap  25  are locked to each other and the locking can be released by the inner insertion portion  23 . Accordingly, the cap  25  is prevented from being unexpectedly detached from the mantle portion  22 . 
     The gastrostomy catheter set  2 S 1  according to the embodiment of the present invention is configured to include the gastrostomy catheter  24  having the foldable gastrointestinal fixing portion (bumper  24   a ) at the tip and the cap  25  covering at least a portion of the folded bumper  24   a.    
     The gastrostomy catheter  24  is formed so that a portion of the insertion jig (obturator  21 ) for inserting the gastrostomy catheter  24  into the stomach can be inserted, and the cap  25  has a locked portion (locked block  25   c ) which is locked to the locking claw  22   b  of the obturator  21 . 
     Since the cap  25  has the locked portion which is locked to the obturator  21 , the cap  25  can be prevented from being unexpectedly detached from the gastrostomy catheter  24 . 
     &lt;&lt;Configuration&gt;&gt; 
     Next, the configurations of the insertion jig set  2 S and the insertion jig (obturator  21 ) will be described with reference to  FIGS. 18 to 22 . As described above, the insertion jig set  2 S includes the obturator  21  for inserting the gastrostomy catheter  24  into the body, the gastrostomy catheter  24  attached around the mantle portion  22 , and the cap  25  which is disposed on the tip side of the mantle portion  22  and covers at least a portion of the folded gastrointestinal fixing portion. 
     &lt;Obturator&gt; 
     As described above, the obturator  21  is configured to include the mantle portion  22  and the inner insertion portion  23 . 
     A holding portion  22   d  for holding an extracorporeal fixing portion  24   b  located on a proximal side of the gastrostomy catheter  24  is provided at a central portion of the mantle portion  22 . The holding portion  22   d  has a forked portion extending in a direction intersecting an axial direction of the obturator  21 , and holds the extracorporeal fixing portion  24   b  of the gastrostomy catheter  24  by the forked portion. 
     The gastrostomy catheter  24  which has passed through a distal end of the mantle portion  22  is attached to an outer periphery of a distal end portion of the mantle portion  22 . 
     At a proximal end of the obturator  21 , an operation unit  23   b  continuous to the inner insertion portion  23  is provided at a proximal end of the obturator  21 , and the surgeon reciprocates the operation unit  23   b  in the axial direction with respect to the mantle portion  22  so that the inner insertion portion  23  can reciprocate. 
     As illustrated in  FIG. 20 , four slits  22   c  are formed at a tip portion of the mantle portion  22 , and the slits  22   c  extend in the axial direction of the mantle portion  22  until the slits  22  reach the tip of the mantle portion  22 . The tip portion of the mantle portion  22  is divided into four pieces by the four slits  22   c . The term “extension in the axial direction” means extension including an axial component, and includes not only extension in a direction parallel to the axial direction but also extension in a direction oblique with respect to the axial direction. 
     Since the slit  22   c  is formed at the tip portion of the mantle portion  22 , the tip side of the mantle portion  22  can be easily expanded. For this reason, when the surgeon moves the inner insertion portion  23  forward to release the locking by the locking claws  22   b  as described later, the cap  25  can be smoothly detached from the mantle portion  22 . 
     When the number of the slits  22   c  is four, the distal end portion of the mantle portion  22  can be divided into four pieces, and facing two pieces can be bent and deformed in a well-balanced manner. Therefore, it is preferable because the locking of the locked block  25   c  of the cap  25  and the release of the locking by the locking claw  22   b  described later can be stably performed. However, the present invention is not limited to this configuration, and the number of slits  22   c  is arbitrary as long as a diameter of the distal end portion of the mantle portion  22  can increase to release the locking of the cap  25 . Further, for example, in a case where the mantle portion  22  is formed of a material which can be elastically deformed, the slit  22   c  need not be provided. 
     The mantle portion  22  include the locking portion (locking claw  22   b ) for locking a portion of the cap  25 . 
     The locking claw  22   b  is provided on an inner wall surface of the mantle portion  22 , and is configured to be locked to a constricted portion of the locked block  25   c  of the cap  25  described later. More specifically, the locking claws  22   b  are provided in the facing two pieces of the four pieces divided at the tip portion of the mantle portion  22 . 
     The present invention is not limited to the configuration in which the locking claws  22   b  are provided in the facing two pieces divided at the tip portion of the mantle portion  22 . That is, the number of the locking claws  22   b  is arbitrary, and the locking claws  22   b  may be provided in all of the four pieces divided at the tip portion of the mantle portion  22 . If the locking claws  22   b  are provided in all of the four pieces, each of the locking claws  22   b  disposed at four locations at every 90° in a circumferential direction of the mantle portion  22  is locked to the constricted portion of the locked block  25   c  of the cap  25 . Therefore, it is possible to more suitably maintain the locked state with respect to the cap  25 . 
     Further, as described above, since the plurality of slits  22   c  are further formed, when the tip portion of the mantle portion  22  is further formed of a plurality of pieces, the locking claws  22   b  may be provided in an arbitrary plurality of pieces. 
     The cross section of the locking claw  22   b  according to the present embodiment in the radial direction with respect to the axis of the mantle portion  22  is formed in a trapezoidal shape with the axis side as an upper side. This trapezoid is formed such that an angle on an acute side between a side on a distal side and the other nearby inner wall surface is smaller than an angle on an acute side between a side on a proximal side and the other nearby inner wall surface. That is, a surface formed to include the side on the distal side of the trapezoid is an inclined surface which is more inclined than a surface formed to include the side on the proximal side of the trapezoid. 
     In the present embodiment, the side on the proximal side is formed at a right angle with respect to the other nearby inner wall surface. That is, the surface on the proximal side of the locking claw  22   b  is a surface orthogonal to the axial direction of the mantle portion  22 . The surface on the distal side of the locked block  25   c  provided in the cap  25 , which is the object to be locked by the locking claw  22   b , is also formed in the direction orthogonal to the axial direction of the mantle portion  22  in a state of being inserted into the distal end portion of the mantle portion  22 . 
     When the locked block  25   c  of the cap  25  is inserted into the locking claw  22   b , which is formed as described above, from the distal side, a proximal end surface  25   a  abuts on the inclined surface. Accordingly, a force is naturally applied in the diameter-increasing direction, and the distal end portion of the mantle portion  22  can be easily expanded. 
     Meanwhile, as described above, the surface on the proximal side of the locking claw  22   b  and the surface on the distal side of the locked block  25   c  are surfaces orthogonal to the axial direction of the mantle portion  22 . Therefore, when the locked block  25   c  of the cap  25  is inserted up to the proximal side beyond the locking claw  22   b , even if the cap  25  moves in the axial direction of the mantle portion  22 , It is difficult for a force to be applied in a direction of expanding the distal end portion of the mantle portion  22 , and it is difficult for the locking by the locking claw  22   b  to be released. 
     A protrusion  22   a  which protrudes radially inward is formed in each of the two inner wall surfaces of the mantle portion  22  where the locking claws  22   b  are provided. As will be described later, when the inner insertion portion  23  moves forward through the mantle portion  22  (when the inner insertion portion  23  is inserted from the proximal side to the distal side of the mantle portion  22 ), an outer peripheral surface of the inner insertion portion  23  abuts on the protrusions  22   a . Accordingly, the distal sides of the two pieces of the mantle portion  22  are expanded (bent and deformed radially outward). The protrusion  22   a  is formed in an arc shape in cross section, extends in the circumferential direction, and is disposed on the proximal side from the locking portion (locking claw  22   b ). The inner insertion portion  23  abuts on the protrusions  22   a  and the mantle portion  22  is expanded. Accordingly, the locking between the cap  25  and the mantle portion  22  can be suitably released. 
     In addition, since the protrusion  22   a  is formed in an arc shape in cross section, the distal sides of the two pieces of the mantle portion  22  can be smoothly deformed to the outside in an external direction without obstructing the movement of the inner insertion portion  23  in the axial direction of the mantle portion  22 . However, the shape of the protrusion according to the present invention is not limited to the arc shape in cross section. That is, a triangular cross section or a trapezoidal cross section may be used as long as the surface on the proximal side abutting on the outer surface of the inner insertion portion  23  is an inclined surface which is gently inclined with respect to the axial direction. 
     &lt;Gastrostomy Catheter&gt; 
     The gastrostomy catheter  24  allows the outside of the body and the inside of the stomach to communicate with each other through the fistula, is attached to the outer periphery of the mantle portion  22 , and is fixed by holding the extracorporeal fixing portion  24   b  by the holding portion  22   d  of the obturator  21 . The gastrostomy catheter  24  is configured to include the radially expandable and contractible bumper  24   a  placed in the stomach, the extracorporeal fixing portion  24   b  disposed outside a body surface, and a shaft  24   c  communicating with the bumper  24   a  and the extracorporeal fixing portion  24   b.    
     The bumper  24   a  according to the present embodiment is formed in an umbrella shape, expands in the radial direction perpendicular to the axial direction in a natural state, and can be accommodated in the space  25   s  of the cap  25  described later in a folded and elastically deformed state. The bumper  24   a  is not limited to an umbrella-shaped member as long as it can expand and contract in the radial direction, and may be formed of only a plurality of bendable rod-shaped members. 
     &lt;Cap&gt; 
     When the bumper  24   a  is disposed in the stomach through a fistula (not illustrated), the cap  25  suppresses the resistance applied to the wall surface of the fistula while maintaining the folded state of the bumper  24   a , and thus, the bumper  24   a  is easily inserted into the body. The cap  25  is formed of a hard capsule cover used for food made of a cellulose-based material or a gelatin-based material, or a material decomposed in the body such as polylactic acid, and a distal end side of the cap  25  is formed in a blunt cap shape. 
     More specifically, the cap  25  is integrally formed by the locked block  25   c , a shaft center portion  25   b  which is provided at a radially center portion continuously from the locked block  25   c  and extends in the axial direction, and a peripheral wall  25   d  which is provided on the radially outer side in a continuous manner with a distal side of the shaft center portion  25   b . An outer peripheral portion of the shaft center portion  25   b  and an inner peripheral portion of the peripheral wall  25   d  form a circular deep moat-shaped space  25   s  which can accommodate the folded bumper  24   a.    
     At least a portion of the gastrointestinal fixing portion (bumper  24   a ) is accommodated a portion of the space  25   s  in the cap  25  except for the site (locked block  25   c ) locked to the locking portion (locking claw  22   b ) in a state illustrated in  FIG. 19  in which the inner insertion portion  23  is not inserted into the distal side of the mantle portion  22 . 
     According to this configuration, the cap  25  can accommodate at least a portion of the bumper  24   a  in a state in which the cap  25  is locked to the mantle portion  22 . The space  25   s  is formed in a size which can accommodate the bumper  24   a.    
     Specifically, an outer diameter of the shaft center portion  25   b  is smaller than an inner diameter of the shaft  24   c  of the gastrostomy catheter  24 , and an inner diameter of a proximal end surface of the peripheral wall  25   d  is larger than an outer diameter of the shaft  24   c.    
     A through hole  25   e  extends in the axial direction from the shaft center portion  25   b  to the locked block  25   c . The through hole  25   e  allows a guide wire (not illustrated) to pass therethrough. 
     &lt;&lt;Operation&gt;&gt; 
     Next, an operation of inserting the gastrostomy catheter  24  into the body by the insertion jig set  2 S will be described with reference to  FIGS. 18 to 22 . 
     The surgeon causes the gastrostomy catheter  24  with the extracorporeal fixing portion  24   b  oriented to be located on the proximal side to pass through the distal end portion of the mantle portion  22 , hangs the holding portion  22   d  on the extracorporeal fixing portion  24   b , and attaches the gastrostomy catheter  24  to the mantle portion  22 . The surgeon inserts the cap  25  into the mantle portion  22  while attaching the cap  25  to the gastrostomy catheter  24  so that the bumper  24   a  of the gastrostomy catheter  24  is accommodated in the space  25   s  of the cap  25 , and locks the cap  25  to the locking claw  22   b . Here, a locking position of the cap  25  by the locking claw  22   b  is a position where the locked block  25   c  exceeds the locking claw  22   b  of the mantle portion  22 . 
     Next, the surgeon causes the bumper  24   a  covered with the cap  25  together with the cap  25  to pass through the fistula, and pushes the gastrostomy catheter  24  by the obturator  21  up to a position (a position at which the holding portion  22   d  abuts on the surface of the abdominal wall) at which the bumper  24   a  reaches the inside of the stomach. 
     As illustrated in  FIG. 21 , the surgeon operates to push the operation unit  23   b  to the distal side, and pushes the inner insertion portion  23  to the distal side of the mantle portion  22 . The inner insertion portion  23  abuts on the protrusion  22   a  when the inner insertion portion  23  moves forward through the mantle portion  22  and applies a bending load to the two pieces having the protrusion  22   a  at the distal end portion of the mantle portion  22  to expand the two pieces of the distal end portion of the mantle portion  22 . 
     Therefore, the locking to the locked block  25   c  by the locking claws  22   b  provided at the two distal ends of the mantle portion  22  is released, and the cap  25  can fall into the stomach by its own weight. Since the cap  25  which has fallen into the stomach is a material which is edible or decomposed in the body as described above, the cap  25  is excreted or dissolved together with the content of the stomach and has no effect on the body. 
     In this way, the bumper  24   a  released from the restraint by the cap  25  can be expanded in the radial direction, and the bumper  24   a  of the gastrostomy catheter  24  can be placed in the stomach. 
     In the above description, the configuration is described in which the mantle portion  22  is expanded to release the locking of the locking claw  22   b  and the cap  25  is detached from the mantle portion  22  by the weight of the cap  25 . Further, as illustrated in  FIGS. 21 and 22 , it is preferable that the inner insertion portion  23  is configured to be movable forward up to the position at which the inner insertion portion  23  abuts on the proximal end portion (proximal end surface  25   a ) of the cap  25  and the cap  25  can be detached from the gastrostomy catheter  24  and the mantle portion  22 . 
     According to the above configuration, even if the cap  25  is not detached from the gastrostomy catheter  24  and the mantle portion  22  only by releasing the locking between the locking claw  22   b  and the cap  25 , the inner insertion portion  23  abuts on the proximal end surface  25   a  of the cap  25  such that the cap  25  can be reliably detached. 
     When the inner insertion portion  23  abuts on the proximal end surface  25   a  of the cap  25  and is pushed in to remove the cap  25 , the extracorporeal fixing portion  24   b  is held by the holding portion  22   d  of the obturator  21  and the gastrostomy catheter  24  does not move. Accordingly, the cap  25  can be relatively moved. 
     Modification Example 2-1 
     In the obturator  21  according to the above embodiment, the configuration is described in which the inner insertion portion  23  abuts on the protrusion  22   a  of the mantle portion  22  to expand the distal end portion of the mantle portion  22 . However, the present invention is not limited to this configuration. 
     Next, a locking structure according to Modification Example 2-1 will be described mainly with reference to  FIGS. 23 and 24 .  FIG. 23  is a cross-sectional view illustrating a locking structure between a mantle portion  212  and a cap  25  according to Modification Example 2-1 and illustrates a bent end portion  212   a  in a closed arm state, and  FIG. 24  is a cross-sectional view illustrating the locking structure between the mantle portion  212  and the cap  25  and is a view illustrating the bent end portion  212   a  in an open arm state. 
     A gastrostomy catheter set  2 S 2  according to the present modification example is configured to include the gastrostomy catheter  24  having the foldable gastrointestinal fixing portion (bumper  24   a ) at the tip, and the cap  25  covering at least a portion of the folded bumper  24   a.    
     The gastrostomy catheter  24  is formed so that a portion (the mantle portion  212 ) of the insertion jig (obturator  21 ) for inserting the gastrostomy catheter  24  into the stomach can be inserted, and the cap  25  has the locked portion (locked block  25   c ) which is locked to the locking claw  212   b  of the obturator  21 . 
     Since the cap  25  has the locked block  25   c  which is locked by the locking claw  212   b  of the obturator  21 , the cap  25  can be prevented from being unexpectedly detached from the gastrostomy catheter  24 . 
     In particular, facing two pieces of a distal end portion of the mantle portion  212  form a bent end portion  212   a  which is bent so as to approach an axis toward a distal end in a natural state. A distal end of the bent end portion  212   a  is formed so as to be located on the axis side with respect to a size between the outer surfaces of the inner insertion portion  23 , and the locking claw  212   b  locked to a distal end portion of the locked block  25   c  is formed so as to protrude in the axial direction from the distal end of the bent end portion  212   a.    
     As illustrated in  FIG. 24 , the inner insertion portion  23  pushed in to the distal side with respect to the mantle portion  212  abuts on the bent end portion  212   a , which is a portion of the inner wall surface of the mantle portion  212 , to expand the bent end portion  212   a  of the mantle portion  212 . Accordingly, the locking by the locking portion (the locking claw  212   b ) can be released. 
     Particularly, unlike the mantle portion  22  according to the above embodiment, the facing two pieces of the distal end portion of the mantle portion  212  do not protrude radially outward from other sites of the mantle portion  212 . Accordingly, the inner wall of the gastrostomy catheter  24  does not hinder the deformation. Therefore, compared with the mantle portion, the locked state between the mantle portion  212  and the cap  25  can be released more smoothly than in the mantle portion  22 . 
     The present invention is not limited to the configuration in which the bent end portions  212   a  are provided on the facing two pieces of the distal end portion of the mantle portion  212 . That is, the number of the bent end portions  212   a  is arbitrary, and the bent end portions  212   a  may be provided in all of the four divided pieces in the distal end portion of the mantle portion  212 . If the bent end portions  212   a  are provided in all of the four pieces, each of the bent end portions  212   a  disposed at four positions at every 90° in a circumferential direction of the mantle portion  212  is locked to a constricted portion of the locked block  25   c  of the cap  25 . Therefore, it is possible to more suitably maintain the locked state with respect to the cap  25 . 
     Further, as described above, since the plurality of bent end portions  212   a  are further formed, when the tip portion of the mantle portion  212  is further formed of a plurality of pieces, the bent end portions  212   a  may be provided in an arbitrary plurality of pieces. 
     Modification Example 2-2 
     In the above embodiment, the example is described in which the locking claws  22   b  and  212   b  of the mantle portions  22  and  212  are locked to the locked block  25   c  of the cap  25 . However, the present invention is not limited to this configuration. 
     Next, a locking structure according to Modification Example 2-2 will be described mainly with reference to  FIG. 25 .  FIG. 25  is a cross-sectional view illustrating a locking structure between the gastrostomy catheter  24  and a cap  225  according to Modification Example 2-2. 
     A gastrostomy catheter set  2 S 3  according to the present modification example is configured to include the gastrostomy catheter  24  having the foldable gastrointestinal fixing portion (bumper  24   a ) at the tip, and the cap  225  covering at least a portion of the folded bumper  24   a . The gastrostomy catheter  24  is formed so that a portion (the mantle portion  222 ) of the insertion jig (obturator  21 ) for inserting the gastrostomy catheter  24  into the stomach can be inserted. 
     The cap  225  according to the present modification example has a locking portion (locking protrusion  225   b ) which is locked to the bumper  24   a  of the gastrostomy catheter  24 . 
     For example, the locking protrusion  225   b  is made of an elastic material, and is configured so that the bumper  24   a  is accommodated in a space  225   s  of the cap  225  and is compressed and deformed by a load radially outward from the outer peripheral surface of the bumper  24   a . The cap  225  is locked to the bumper  24   a  by a frictional force due to an elastic restoring force of the locking protrusion  225   b.    
     According to this locking structure, since the cap  225  is locked to the gastrostomy catheter  24 , the cap  225  can be prevented from being unexpectedly detached from the gastrostomy catheter  24 . 
     When the locking by the locking protrusion  225   b  is released, as in the above embodiment, a distal end surface  23   a  of the inner insertion portion  23  abuts on a proximal end surface  225   a  of the cap  225 , and the inner insertion portion  23  may be pushed to the distal side up to the position at which the locking protrusion  225   b  is detached from the bumper  24   a.    
     In addition, a locking portion (not illustrated) which is locked to the inner surface of the peripheral wall  225   d  of the cap  225  may be provided on the bumper  24   a  of the gastrostomy catheter  24  without providing the locking protrusion  225   b  on the inner surface of the peripheral wall  225   d  of the cap  225 . 
     Modification Example 2-3 
     In Modification Example 2-2, the cap  225  having the locking protrusion  225   b  for locking the umbrella-shaped bumper  24   a  is described. However, the present invention is not limited to this configuration. 
     Next, a locking structure according to Modification Example 2-3 will be described mainly with reference to  FIGS. 26 and 27 .  FIG. 26  is a cross-sectional view illustrating a locking structure between a gastrostomy catheter  234  and a cap  235  according to the Modification Example 2-3 and is a view illustrating a locked state. 
       FIG. 27  is a cross-sectional view illustrating the locking structure between the gastrostomy catheter  234  and the cap  235  and is a view illustrating an unlocked state. 
     The gastrostomy catheter set  2 S 4  according to the present modification example is configured to include the gastrostomy catheter  234  having a foldable gastrointestinal fixing portion (bumper  234   a ) at the tip, and the cap  235  covering at least a portion of the folded bumper  234   a.    
     The gastrostomy catheter  234  is formed so that a portion (mantle portion  222 ) of the insertion jig for inserting the gastrostomy catheter  234  into the stomach can be inserted, and the cap  235  has the locking portion (locking protrusion  235   b ) which is locked to the gastrostomy catheter  234 . 
     In particular, the bumper  234   a  includes a wire  234   b  which is coiled inside the bumper  234   a . The bumper  234   a  is accommodated in the space  235   s  of the cap  235  in a state in which the wire  234   b  is contracted toward an axis of the bumper  234   a  from the natural state. 
     When the locking protrusion  235   b  of the cap  235  abuts on the wire  234   b  inside the bumper  234   a  via the bumper  234   a , the cap  235  is locked to the gastrostomy catheter  234 . 
     The inner insertion portion  23  is configured to be movable forward through the mantle portion  222  up to a position at which the inner insertion portion  23  abuts on a proximal end portion (proximal end surface  235   a ) of the cap  235  and the cap  235  can be detached from the gastrostomy catheter  234  and the mantle portion  222 . Specifically, the distal end surface  23   a  of the inner insertion portion  23  abuts on a proximal end surface  235   a  of the cap  235 , and the cap  235  is pushed in a distal direction by the inner insertion portion  23  up to a position at which the locking protrusion  235   b  crosses the wire  234   b . By pushing the cap  235  in this manner, the cap  235  can be detached from the gastrostomy catheter  234  as illustrated in  FIG. 27 . 
     The surgeon removes the cap  235  in the body, and thus, the surgeon can increase a diameter of the bumper  234   a  by biasing when the wire  234   b  is restored in a diameter-increasing direction. A diameter of the bumper  234   a  increases to be larger than a diameter of a fistula (not illustrated), and thus, a distal end of the gastrostomy catheter  234  is placed in the stomach. 
     The configuration is described in which the locking protrusions  225   b  and  235   b  of the caps  225  and  235  according to the above modification example are locked to the portions of the bumpers  24   a  and  234   a  of the gastrostomy catheters  24  and  234 . However, the present invention is limited to this configuration, the locking protrusions  225   b  and the  235   b  may be locked to the shaft portion. 
     Further, in the above embodiment, the configuration is described in which the inner insertion portion  23  directly abuts on the member including the locking portion or a member to be locked and presses the member and the locking by the locking portion is released. However, the inner insertion portion  23  may indirectly press the member via a third member to release the locking. 
     The present embodiment includes the following technical concepts. 
     (1) A gastrostomy catheter including: a shaft in which a lumen is provided; a flexible bumper which is provided at a tip of the shaft; and a linear member which has elasticity and biases the bumper in a diameter-increasing direction or restricts deformation of the bumper in a diameter-decreasing direction. 
     (2) In the gastrostomy catheter according to (1), the linear member is configured to be changed to a first state in which at least a portion of the linear member is disposed in the bumper and the bumper is biased radially outward or the deformation of the bumper in the diameter-decreasing direction is restricted, and a second state in which the linear member is disposed closer to a base end side of the bumper or the linear member is pulled out closer to a proximal side from the bumper than when the linear member is in the first state, and the linear member biases the bumper radially outward lower than when the linear member is in the first state or does not bias the bumper, or the linear member allows the deformation of the bumper in the diameter-decreasing direction more than when the linear member is in the first state. 
     (3) In the gastrostomy catheter according to (1) or (2), a fixing portion for holding the gastrostomy catheter at a predetermined position is provided at a base end portion of the shaft, and a base end holding portion which holds a base end portion of the linear member is provided in the fixing portion or on a proximal side from a distal end of the fixing portion. 
     (4) In the gastrostomy catheter according to (3), the base end holding portion holds the base end portion by the base end portion of the linear member being embedding in the base end holding portion and is provided to be cuttable to the fixing portion. 
     (5) In the gastrostomy catheter according to (3), the base end holding portion is detachably attached to the fixing portion. 
     (6) In the gastrostomy catheter according to any one of (1) to (5), the lumen includes a main lumen for injecting a nutrient and a sub-lumen which accommodates at least a portion of the linear member, and a tip opening portion of the sub-lumen is continuous with an inside of the bumper. 
     (7) In the gastrostomy catheter according to (6), a portion of an inner wall of the bumper is located on an extension of the sub-lumen. 
     (8) In the gastrostomy catheter according to (6) or (7), a tip portion of the sub-lumen is formed to be bent outward in a radial direction of the bumper. 
     (9) In the gastrostomy catheter according to any one of (6) to (8), in a state in which the linear member is disposed over the sub-lumen and the bumper, a site of the linear member disposed in the sub-lumen and a site thereof disposed in the bumper are bent and formed continuously. 
     (10) In the gastrostomy catheter according to (9), in the state in which the linear member is disposed over the sub-lumen and the bumper, at least a portion of the site of the linear member disposed in the bumper is bent and formed to extend in a direction along an inner peripheral surface of the bumper. 
     (11) In the gastrostomy catheter according to any one of (1) to (10), a communication hole which allows an inside and an outside of the bumper to communicate with each other is formed in the bumper, and a tip portion of the linear member is disposed so as to be movable in the bumper and put in and out of the bumper through the communication hole. 
     (12) In the gastrostomy catheter according to any one of (1) to (11), at least a tip portion of the linear member is covered with a coating portion having a hardness lower than that of the linear member or is formed to be blunt. 
     (13) The gastrostomy catheter according to any one of (1) to (12), further including: a cover which holds and accommodates the folded bumper, in which the cover holds and accommodates the bumper in a state in which at least a portion of the linear member disposed in the bumper. 
     (14) In the gastrostomy catheter according to any one of (1) to (13), a maximum diameter portion of the bumper is formed at a position separated from the tip of the shaft toward a tip side. 
     (15) In the gastrostomy catheter according to any one of (1) to (14), a concave portion which is depressed in a radial direction of the bumper and extends along an axial direction of the bumper is formed on a surface of the bumper. 
     (16) In the gastrostomy catheter according to (15), the bumper includes a large diameter portion having a maximum diameter portion and a small diameter portion provided on a tip side from the large diameter portion, a plurality of the concave portions are formed in each of the large diameter portion and the small diameter portion, and the concave portions in the large diameter portion and the small diameter portion are formed at corresponding positions in a circumferential direction of the bumper. 
     (17) In the gastrostomy catheter according to any one of (1) to (16), the bumper includes an inner layer and an outer layer, a space is provided between the inner layer and the outer layer, and a portion of the linear member is disposed in the space. 
     (18) In the gastrostomy catheter according to (17), the bumper includes a large diameter portion having a maximum diameter portion and a small diameter portion provided on a tip side of the large diameter portion, the inner layer and the outer layer are separated from each other in the large diameter portion, and the inner layer and the outer layer are in contact with each other in the small diameter portion. 
     (19) In the gastrostomy catheter according to (1) or (2), the shaft has a tip portion which is formed to have a diameter smaller than those of other sites, and the bumper extends from the tip portion of the shaft. 
     (20) In the gastrostomy catheter according to (3), the fixing portion includes a support portion which movably supports the base end holding portion, and a restriction unit which is connected to the support portion, is provided on a direction in which the base end holding portion is detached from the support portion, and restricts a movement of the base end holding portion and detachment of the base end holding portion from the support portion, and the base end holding portion is configured so as to be separable from the support portion by the restriction unit being separated from the support portion. 
     (21) In the gastrostomy catheter according to (20), the base end holding portion has an inverted tapered portion formed to expand toward an outside of the fixing portion, the support portion includes a facing portion which extends along the inverted tapered portion, and the support portion is configured to be deformable so that the facing portion abuts on the inverted tapered portion and the base end holding portion is pushed into the outside of the fixing portion after the restriction unit is separated from the support portion. 
     (22) In an insertion jig set for inserting a gastrostomy catheter having a foldable gastrointestinal fixing portion at a tip into a body, the insertion jig set including: an insertion jig configured to include a tubular mantle portion and an inner insertion portion which is movable forward and rearward through the mantle portion; the gastrostomy catheter which is attached around the mantle portion; and a cap which is disposed on a tip side of the mantle portion and covers at least a portion of the folded gastrointestinal fixing portion, in which one of the gastrostomy catheter or the mantle portion and the cap has a locking portion which is locked to the other, and the inner insertion portion releases locking by the locking portion when the inner insertion portion moves forward through the mantle portion. 
     (23) In the insertion jig set according to (22), the locking portion is provided on an inner wall surface of the mantle portion and is configured to be lockable to the cap, and the inner insertion portion abuts on a portion of the inner wall surface of the mantle portion to expand the mantle portion, and thus, releases the locking by the locking portion. 
     (24) In the insertion jig set according to (23), a protrusion protruding radially inward is formed on the inner wall surface of the mantle portion, the protrusion is disposed on a proximal side from the locking portion, and the inner insertion portion abuts on the protrusion to expand the mantle portion when the inner insertion portion moves forward through the mantle portion. 
     (25) In the insertion jig set according to (23) or (24), a slit is formed at a tip portion of the mantle portion, and the slit extends in an axial direction of the mantle portion up to a tip of the mantle portion. 
     (26) In the insertion jig set according to any one of (22) to (25), the inner insertion portion is configured to be movable forward up to a position at which the inner insertion portion abut on a proximal end portion of the cap and the cap is detachable from the gastrostomy catheter and the mantle portion. 
     (27) In the insertion jig set according to any one of (22) to (26), at least a portion of the gastrointestinal fixing portion is accommodated in a portion of a space in the cap except for the locking portion or a site locked to the locking portion. 
     (28) In an insertion jig for inserting a gastrostomy catheter having a foldable gastrointestinal fixing portion at a tip and a cap covering at least a portion of the folded gastrointestinal fixing portion into a body, the insertion jig including: a tubular mantle portion around which the gastrostomy catheter is attachable; and an inner insertion portion which passes through the mantle portion, in which the mantle portion has a locking portion which is locked to the cap, and the inner insertion portion releases locking by the locking portion when the inner insertion portion moves forward through the mantle portion. 
     (29) A gastrostomy catheter set including: a gastrostomy catheter which has a foldable gastrointestinal fixing portion at a tip; and a cap which covers at least a portion of the folded gastrointestinal fixing portion, in which the gastrostomy catheter is formed so that a portion of an insertion jig for inserting the gastrostomy catheter into the stomach is inserted, and the cap has a locked portion which is locked to the insertion jig. 
     (30) A gastrostomy catheter set including: a gastrostomy catheter which has a foldable gastrointestinal fixing portion at a tip; and a cap which covers at least a portion of the folded gastrointestinal fixing portion, in which the gastrostomy catheter is formed so that a portion of an insertion jig for inserting the gastrostomy catheter into the stomach is inserted, and one of the gastrostomy catheter and the cap has a locking portion which is locked to the other. 
     INDUSTRIAL APPLICABILITY 
     It is possible to provide a gastrostomy catheter capable of reducing time and effort required for management while keeping a resistance applied to a body low and capable of being placed for a relatively long time. Further, it is possible to provide an insertion jig set, an insertion jig, and a gastrostomy catheter set capable of preventing the cap from being unexpectedly detached from the gastrostomy catheter and capable of suitably removing the cap. 
     REFERENCE SIGNS LIST 
     
         
         
           
               11 : gastrostomy catheter 
               12 : shaft 
               13 : bumper 
               13   a : communication hole 
               14 : wire (linear member) 
               14   a : base end portion 
               14   b : tip portion 
               14   c : coating portion 
               14   j ,  14   k : bending point 
               14   x : first site 
               14   y : second site 
               15 : extracorporeal fixing unit (fixing portion) 
               15   a : distal end 
               15   b : marker 
               15   c : base end holding portion 
               16 : cap 
               17 : strap 
               18 : main lumen (lumen) 
               18   a : opening 
               19 : sub-lumen (lumen) 
               19   a : base end portion 
               19   b : tip opening portion 
               110 : capsule cover 
               111 : insertion jig 
               111   a : main body tube 
               111   b : claw 
               111   c : operation unit 
               111   d : piston 
               111   e : extrusion rod 
               113 : bumper 
               113   a : communication hole 
               115 : extracorporeal fixing unit (fixing portion) 
               115   a : base end holding portion 
               115   b : locking protrusion 
               115   c : concave groove 
               122 : shaft 
               129 : sub-lumen (lumen) 
               129   b : tip opening portion 
               132 : shaft 
               132   a : shaft main body 
               132   b : first tip portion (tip portion) 
               132   c : second tip portion (tip portion) 
               132   d : sub-lumen 
               133 : bumper 
               133   s : space 
               134 : inner layer 
               134   a : connection tubular portion 
               134   b : inclined portion 
               134   c : concave portion 
               134   d : tip portion 
               134   e : concave portion 
               135 : outer layer 
               135   a : connection tubular portion 
               135   b : large diameter portion 
               135   c ,  135   d : inclined portion 
               135   e : maximum diameter portion 
               135   f : concave portion 
               135   g : small diameter portion 
               135   h : concave portion 
               145 : extracorporeal fixing unit (fixing portion) 
               146 : support portion 
               146   a : facing portion 
               146   b : connection wall 
               146   c : bottom wall 
               146   d : opening 
               146   e : through hole 
               147 : restriction piece (restriction unit) 
               148 : base end holding portion 
               148   a : inverted tapered portion 
               150 : abdominal wall 
               151 : stomach wall 
               152 : inside stomach 
               153 : fistula 
               1 α,  1 α 1 ,  1 α 2 : incident angle 
               2 S: insertion jig set 
               2 S 1 ,  2 S 2 ,  2 S 3 ,  2 S 4 : gastrostomy catheter set 
               21 : obturator (insertion jig) 
               22 : mantle portion 
               22   a : protrusion 
               22   b : locking claw (locking portion) 
               22   c : slit 
               22   d : holding portion 
               23 : inner insertion portion 
               23   a : distal end surface 
               23   b : operation unit 
               24 : gastrostomy catheter 
               24   a : bumper (gastrointestinal fixing portion) 
               24   b : extracorporeal fixing portion 
               24   c : shaft 
               25 : cap 
               25   a : proximal end surface 
               25   b : shaft center portion 
               25   c : locked block (locked portion) 
               25   d : peripheral wall 
               25   e : through hole 
               25   s : space 
               212 : mantle portion 
               212   a : bent end portion 
               212   b : locking claw (locking portion) 
               222 : mantle portion 
               225 : cap 
               225   a : proximal end surface 
               225   b : locking protrusion (locking portion) 
               225   d : peripheral wall 
               225   s : space 
               234 : gastrostomy catheter 
               234   a : bumper (gastrointestinal fixing portion) 
               234   b : wire 
               235 : cap 
               235   a : proximal end surface 
               235   b : locking protrusion (locking portion) 
               235   s : space