Overtube

Abstract

To provide an overtube with improved insertion property of an overtube end side with respect to a digestive tract.SOLUTION: An overtube 10 includes: a supply / discharge port 22 for supplying and discharging fluid; a first region T1 which is located on an end side of the supply / discharge port 22 and includes an outer tube 30, an inner tube 32, and a shape variable body 38; and a second region T2 which is located on the end side of the first region T1 and includes the outer tube 30 and the inner tube 32. The first region T1 is switchable to a first state in which fluid is supplied for a tube internal space S between the outer tube 30 and the inner tube 32 via the supply / discharge port 22 and a second state that is harder than the first state and in which the fluid is discharged. The second region T2 is softer than the second state of the first region T1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an overtube having an insertion passage through which a medical instrument can be inserted. [Background technology]

[0002] 2. Description of the Related Art An overtube having an insertion passage through which a medical instrument such as an insertion portion of an endoscope (hereinafter also referred to as an "endoscope insertion portion") can be inserted is known.

[0003] For example, Patent Document 1 discloses a hardness-variable overtube (guide tube). This overtube has a tube body in which an outer tube covers the periphery of an inner tube, and a shape-variable body that is deformable to follow the shape of the tube body is provided between the outer tube and the inner tube.

[0004] According to the overtube disclosed in Patent Document 1, when the internal space between the outer tube and the inner tube is decompressed, the overtube becomes hard (hardened) with the shape of the shape-variable body maintained. On the other hand, when the decompression of the internal space between the outer tube and the inner tube is released, the shape maintenance by the shape-variable body is released and the overtube becomes soft (softened). With the endoscope insertion section inserted through the overtube, the overtube can be switched between the hardened and softened states while performing a moving operation to move the overtube and the endoscope insertion section back and forth, thereby guiding the endoscope insertion section into the body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 181200 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a hardness-variable overtube as disclosed in Patent Document 1, when the overtube is switched from a softened state to a hardened state, the overtube becomes hard over the entire longitudinal direction, which reduces the insertability of the tip side of the overtube into the digestive tract (particularly the upper digestive tract). This is also true when the overtube is in a softened state. This makes the above-mentioned movement operation complicated and difficult, and there are cases where the endoscope insertion part cannot be guided in the desired direction.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an overtube with improved insertability of the tip side of the overtube into the digestive tract. [Means for solving the problem]

[0008] The present disclosure includes the following inventions.

[0009] The overtube of the first embodiment is an overtube having an insertion passage through which a medical instrument can be inserted, and is equipped with: a supply / discharge port located on the base end side for supplying and discharging fluid; a first region located distally of the supply / discharge port and including a flexible outer tube, a flexible inner tube, and a deformable shape-variable body provided between the outer tube and the inner tube; and a second region located distally of the first region and including the outer tube and the inner tube, wherein the first region is switchable between a first state in which fluid is supplied to the space between the outer tube and the inner tube via the supply / discharge port and a second state which is harder than the first state in which fluid is discharged, and the second region is softer than the second state of the first region.

[0010] In the overtube according to the second aspect, in the first aspect, the second region is softer than the first region in the first state.

[0011] The overtube according to the third aspect is the overtube according to the first or second aspect, wherein the distal end side of the second region is softer than the proximal end side of the second region.

[0012] The overtube of the fourth aspect is any one of the first to third aspects, wherein the second region includes a shape-changing body, and the second region is switchable between a first state in which fluid is supplied to the space between the outer tube and the inner tube via the supply / discharge port, and a second state in which the fluid is discharged.

[0013] The overtube of the fifth aspect is any one of the first to fourth aspects, wherein the first state of the second region is softer than the first state of the first region, and the second state of the second region is softer than the second state of the first region.

[0014] In the overtube of the sixth aspect, in the first to fifth aspects, the first region is provided between the outer tube and the inner tube and has an intermediate layer capable of contacting the shape-variable body, and in the second state, the first region becomes hardened by contact between a first contact surface provided on the shape-variable body and a second contact surface provided on the intermediate layer that faces the first contact surface.

[0015] The overtube according to a seventh aspect is the overtube according to any one of the first to sixth aspects, wherein the second region includes an intermediate layer having a configuration different from that of the intermediate layer of the first region.

[0016] An overtube according to an eighth embodiment is the overtube according to the seventh embodiment, wherein the intermediate layer of the second region has a certain degree of flexibility along the longitudinal direction.

[0017] An overtube according to a ninth embodiment is the overtube of the seventh embodiment, wherein the intermediate layer of the second region is softer on the distal end side than on the proximal end side.

[0018] The overtube of the 10th aspect is the same as that of the 9th aspect, in which the intermediate layer of the second region has a first intermediate layer provided on the tip side and a second intermediate layer provided on the base side, and the first intermediate layer is softer than the second intermediate layer.

[0019] An overtube according to an eleventh embodiment is the overtube of the ninth embodiment, wherein the intermediate layer of the second region becomes gradually softer toward the tip side.

[0020] The overtube of the 12th aspect is any of the 7th to 11th aspects, in which the intermediate layer is composed of a sheet material extending from the first region to the second region, and a cut portion is provided in the sheet material in the second region.

[0021] The overtube according to a thirteenth aspect is the overtube according to the twelfth aspect, wherein the sheet material of the first region has a smooth surface.

[0022] The overtube according to a fourteenth aspect is the overtube of any one of the sixth to thirteenth aspects, wherein at least a portion of either the first contact surface or the second contact surface includes a high-friction surface.

[0023] The overtube according to a fifteenth aspect is the same as in any one of the sixth to fourteenth aspects, in which the intermediate layer is provided between the outer tube and the shape-variable body.

[0024] An overtube according to a sixteenth aspect is based on any one of the first to fifteenth aspects, wherein the shape-variable body has a helical tube formed by helically winding a belt-shaped member on the outer circumferential side of the inner tube.

[0025] The overtube of the 17th aspect is any of the 1st to 16th aspects, wherein the length of the second region in the longitudinal direction is 5 cm or more and 20 cm or less, and the base end of the second region is located within 20 cm of the tip.

[0026] An overtube according to an eighteenth aspect is the overtube according to any one of the first to seventeenth aspects, wherein the length of the first region in the longitudinal direction is longer than that of the second region.

[0027] The overtube according to a nineteenth aspect is the overtube according to any one of the first to eighteenth aspects, wherein the length of the first region in the longitudinal direction is 20 cm or more.

[0028] The overtube of the 20th aspect is the same as any of the 3rd aspect, 9th aspect to 11th aspect, in which the length of the second region in the longitudinal direction is 5 cm or more and 50 cm or less, and the base end of the second region is located within 50 cm of the tip.

[0029] The insertion method of the endoscope insertion part of the 21st aspect is an insertion method using an overtube of any of the 1st to 20th aspects, and includes an insertion step of inserting the endoscope insertion part into the overtube from the mouth of the subject and into the stomach, an alignment step of aligning the tip of the endoscope insertion part to a position where it is exposed from the tip of the overtube, and a pylorus passing step of pushing the endoscope insertion part and the overtube together and passing the endoscope insertion part and the overtube through the pylorus after the insertion step and the alignment step are performed.

[0030] The method of inserting an endoscope insertion portion according to the 22nd aspect is the same as in the 21st aspect, and includes a retracting step of retracting the endoscope insertion portion and the overtube together and moving a portion of the overtube toward the small bay portion to reduce slack in the overtube.

[0031] The method for inserting an endoscope insertion portion according to a twenty-third aspect is the twenty-first or twenty-second aspect, further comprising a hardening step of hardening the overtube.

[0032] The insertion method of the endoscope insertion portion of the 24th aspect is an insertion method using an overtube of any of the 1st to 20th aspects, and includes an insertion step of inserting the endoscope insertion portion into the overtube from the subject's mouth into the stomach, an endoscope pylorus passing step of pushing the endoscope insertion portion after the insertion step, and passing at least a part of the curved portion of the endoscope insertion portion through the pylorus, and an overtube pylorus passing step of pushing the overtube to pass it through the pylorus after the endoscope pylorus passing step.

[0033] The method of inserting an endoscope insertion portion according to the 25th aspect includes, in the 24th aspect, an alignment step of aligning the tip of the endoscope insertion portion to a position where it is exposed from the tip of the overtube after the overtube pylorus passing step is performed.

[0034] The method of inserting an endoscope insertion portion according to the 26th aspect, in the 24th or 25th aspect, includes a retracting step of retracting the endoscope insertion portion and the overtube together and moving a portion of the overtube material toward the small bay portion to reduce slack in the overtube.

[0035] The method for inserting an endoscope insertion portion according to a 27th aspect is the method according to any one of the 24th to 26th aspects, further comprising a hardening step of hardening the overtube.

[0036] The method of inserting an endoscope insertion portion according to the 28th aspect includes, after the hardening step in the 27th aspect, an insertion step of pushing the endoscope insertion portion against the overtube to insert the endoscope insertion portion deep inside the body. Effect of the Invention

[0037] According to the present invention, it is possible to improve the insertability of the distal end side of the overtube into the digestive tract. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an endoscope apparatus. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing the configuration of the first region of the overtube. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing the configuration of the second region of the overtube. [Figure 4] FIG. 4 is a diagram showing a state in which an overtube is pushed into an endoscope insertion portion. [Diagram 5] FIG. 5 is a flow chart showing the steps of a first example of a transpylorus procedure. [Figure 6]FIG. 6 is an explanatory diagram for explaining a first example of a pylorus-passing procedure. [Figure 7] FIG. 7 is a flow chart showing the steps of a second example of a transpylorus procedure. [Figure 8] FIG. 8 is an explanatory diagram for explaining a second example of a pylorus-passing procedure. [Figure 9] FIG. 9 is a schematic cross-sectional view showing the configuration of the overtube of the second embodiment. [Figure 10] FIG. 10 is a planar view of a sheet material provided on the overtube of the second embodiment. [Figure 11] FIG. 11 is an external view of the overtube of the second embodiment with the outer tube omitted. [Figure 12] FIG. 12 is a diagram showing the sheet material according to the first modified example developed into a plane. [Figure 13] FIG. 13 is a diagram showing the sheet material according to the second modified example developed into a plane. [Figure 14] FIG. 14 is a diagram showing a sheet material according to the third modified example developed into a plane. [Figure 15] FIG. 15 is a diagram showing a sheet material according to the fourth modified example developed into a plane. [Figure 16] FIG. 16 is a diagram showing a sheet material according to the fifth modified example developed into a plane. [Figure 17] FIG. 17 is a diagram showing a sheet material according to the sixth modified example developed into a plane. [Figure 18] FIG. 18 is a diagram showing the evaluation results of the degree of bending of the overtube. [Figure 19] FIG. 19 is a graph showing the results of measuring the hardness of the second region of the overtube. [Figure 20] FIG. 20 is a diagram showing another configuration example of the overtube of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0040] [First embodiment] Fig. 1 is a schematic diagram showing the configuration of an endoscope device 1. As shown in Fig. 1, the endoscope device 1 includes an overtube 10 and an endoscope 100. Before describing the specific configuration of the overtube 10 to which the present invention is applied, the configuration of the endoscope 100 will be briefly described below.

[0041] <Endoscope> The endoscope 100 comprises a long insertion portion 102 (hereinafter referred to as the “endoscope insertion portion 102”) that is inserted into the body, and a handheld operation portion 110 that is connected to the base end side of the endoscope insertion portion 102.

[0042] The endoscope insertion section 102 is composed of a tip section 104, a bending section 106, and a flexible section 108 in that order from the tip side to the base end side.

[0043] Although not shown, the distal end surface 104a of the distal end portion 104 is provided with a pair of illumination windows for illuminating the inside of the body, an observation window for observing the inside of the body, a treatment tool outlet for outletting a treatment tool, and a cleaning nozzle for cleaning the observation window.

[0044] The bending section 106 is bent in a desired direction by operating a pair of angle knobs (not shown) provided on the hand-held operation section 110. The flexible section 108 is made of a soft member that is flexible in the bending direction. Note that the configuration of the endoscope 100 is not directly related to the present invention and a known configuration is applied, so further explanation will be omitted.

[0045] <Overtube> Next, a configuration of the overtube 10 will be described. The overtube 10 is a device for guiding the endoscope insertion portion 102 into the body, and is a hardness-variable overtube whose hardness can be changed. The endoscope insertion portion 102 is an example of the medical instrument of the present invention.

[0046] 1, the overtube 10 is an elongated member formed along a longitudinal axis C extending from a distal end 10a to a proximal end 10b. Note that in the direction along the longitudinal axis C, one side (the distal end 10a side) is referred to as the distal direction (the direction indicated by symbol C1 in FIG. 1) or the distal side, and the other side (the proximal end 10b side) which is the opposite direction is referred to as the proximal direction (the direction indicated by symbol C2 in FIG. 1) or the proximal side.

[0047] An insertion passage 14 is provided inside the overtube 10 along the longitudinal axis C. The insertion passage 14 opens at both the tip 10a and the base end 10b of the overtube 10, and communicates between the tip opening (tip opening) and the base opening (base opening). The inner diameter of the insertion passage 14 is formed larger than the outer diameter of the endoscope insertion part 102, so that the endoscope insertion part 102 can be inserted into the insertion passage 14.

[0048] A distal end cap 18 is provided on the distal end side of the overtube 10, and a proximal end cap 20 is provided on the proximal end side.

[0049] The portion of the overtube 10 excluding the distal end cap 18 and the proximal end cap 20 (hereinafter referred to as the "tube main body"), i.e., the region occupying most of the tube 10 excluding both ends (proximal and proximal portions) in the direction along the longitudinal axis C, is configured as an elongated cylindrical tube along the longitudinal axis C. Note that, as will be described in detail later, the tube main body constituting the overtube 10 is configured as a double-structure tube in which an outer tube 30 covers the periphery of an inner tube 32, and a space S (hereinafter referred to as the "tube internal space S") is provided between the outer tube 30 and the inner tube 32 (see FIG. 2).

[0050] The tip cap 18 is a member that constitutes the tip side of the overtube 10. The tip cap 18 is a cylindrical body made of hard resin that is coaxially fixed to the tip side of the tube main body, and constitutes an opening on the tip side of the overtube 10 and a part of the insertion passage 14. The tip cap 18 also serves as a sealing member for sealing the end on the tip side of the tube internal space S.

[0051] The base end cap 20 is a member that constitutes the base end side of the overtube 10. The base end cap 20 is a cylindrical body made of hard resin that is coaxially fixed to the base end side of the tube main body, and constitutes the opening on the base end side of the overtube 10 and part of the insertion passage 14. The base end cap 20 also serves as a sealing member for sealing the end on the base end side of the tube internal space S.

[0052] The base end cap 20 has a predetermined length along the longitudinal axis C (at least a length that can be grasped by an operator such as a surgeon or an assistant) and functions as a gripping portion that is grasped by the operator.

[0053] An inlet / outlet port 22 is provided on the outer peripheral surface of the base end cap 20. The inlet / outlet port 22 is connected to the tube internal space S via a communication conduit (not shown) provided inside the outer peripheral wall of the base end cap 20. The inlet / outlet port 22 is connected to a pump 26 via a fluid inlet / outlet tube 24. This makes it possible to supply and discharge a fluid (air in this example) to and from the tube internal space S through the inlet / outlet port 22 by operating the pump 26. The fluid to be sent into the tube internal space S is not limited to air, and various other gases may be used, or a liquid may also be used.

[0054] The overtube 10 has a first region T1 located on the distal side of the supply / discharge port 22, and a second region T2 located on the distal side of the first region T1. Specifically, the second region T2 is a region having a predetermined length from the distal end (proximal end of the distal cap 18) of the tube main body constituting the overtube 10 toward the proximal direction C2. The first region T1 is a region from the proximal end of the second region T2 to the proximal end of the tube main body (the distal end of the proximal cap 20).

[0055] It is not necessary to provide the tip cap 18 on the tip side of the overtube 10. In this case, the tube internal space S is sealed on the tip side of the tube main body. When the tip cap 18 is not provided, the tip 10a of the overtube 10 and the tip of the second region T2 substantially coincide with each other.

[0056] Next, the configurations of the first region T1 and the second region T2 of the overtube 10 will be described in detail. FIG. 2 is a schematic cross-sectional view showing the configuration of the first region T1 of the overtube 10. FIG. 3 is a schematic cross-sectional view showing the configuration of the second region T2 of the overtube 10. Note that FIG. 3 also illustrates a part of the first region T1 to show the difference between the first region T1 and the second region T2. ​​Below, the configuration common to the first region T1 and the second region T2 will be described first, and then the configurations different between the first region T1 and the second region T2 will be described.

[0057] 2 and 3, the tube main body constituting the overtube 10 has a cylindrical tube outer peripheral wall 16 extending from its tip to its base end. The tube outer peripheral wall 16 is formed of a double-structure tube in which an outer tube 30 covers the periphery of an inner tube 32. That is, the tube main body has a flexible outer tube 30 and a flexible inner tube 32 disposed inside the outer tube 30, and a tube internal space S is provided between the outer tube 30 and the inner tube 32. A shape-changing body 38 and a sheet material 40, which will be described later, are disposed in the tube internal space S. Note that, as will be described later, in this embodiment, the sheet material 40 is disposed only in the first region T1.

[0058] The outer tube 30 and the inner tube 32 are each made of a soft resin material such as urethane or polyester resin. The outer tube 30 and the inner tube 32 are not limited to the above-mentioned examples, and any material having an elastic modulus of 5 MPa (megapascals, the same applies below) to 20 MPa at an elongation rate of 100% (percent, the same applies below) as determined by a method described in JIS K7161 (tensile test) or a method conforming thereto can be used.

[0059] The thickness of the outer tube 30 and the inner tube 32 is, for example, about 100 μm (micrometers, the same applies below) to 200 μm each. From the viewpoint of preventing breakage, it is preferable that the thickness of the outer tube 30 is thicker than that of the inner tube 32. The rigidity of the outer tube 30 and the inner tube 32 is smaller than that of the sheet material 40 described later.

[0060] The tube internal space S is a space whose cross-sectional shape in a direction perpendicular to the longitudinal axis C is formed in an annular (donut-shaped) shape so as to surround the periphery (outer periphery) of the inner tube 32. This tube internal space S is formed as an enclosed space by sealing the outer tube 30 and the inner tube 32 at the distal end side and proximal end side of the overtube 10 with the distal end cap 18 and proximal end cap 20 described above.

[0061] The thickness of the tube internal space S is, for example, about 600 μm to 800 μm when the thickness D of the tube outer peripheral wall 16 of the overtube 10 in a softened state is 1 mm (millimeter, the same applies below) or less. The thicknesses of the outer tube 30, the inner tube 32, and the tube internal space S are not limited to the above-mentioned thicknesses, but are set based on the diameter of the endoscope insertion part 102 and the diameter of the insertion path into which the endoscope insertion part 102 is inserted, etc. The inner diameter of the inner tube 32 (i.e., the inner diameter of the insertion passage 14) is also set according to the outer diameter of the endoscope insertion part 102, and the inner diameter is, for example, about 6 mm to 16 mm.

[0062] The outer peripheral surface 30a of the outer tube 30 and the inner peripheral surface 32a of the inner tube 32 each have a hydrophilic coating. By forming a hydrophilic coating on the outer peripheral surface 30a of the outer tube 30, it is possible to reduce frictional resistance between the outer tube 30 and the digestive tract wall. As a result, the insertability (advancement) of the overtube 10 into the body is improved. In addition, by forming a hydrophilic coating on the inner peripheral surface 32a of the inner tube 32, it is possible to reduce frictional resistance between the inner tube 32 and the endoscope insertion portion 102. As a result, the insertability of the endoscope insertion portion 102 into the overtube 10 is improved.

[0063] In this example, a hydrophilic coating is formed on both the outer tube 30 and the inner tube 32, but the present invention is not limited to this, and it is sufficient that the hydrophilic coating is formed on at least one of the outer tube 30 and the inner tube 32. However, it is preferable to form a hydrophilic coating on both the outer tube 30 and the inner tube 32, since the above-mentioned two effects can be obtained.

[0064] A shape variable body 38 is provided between the outer tube 30 and the inner tube 32 (i.e., in the tube internal space S). As shown in Figs. 2 and 3, the shape variable body 38 is provided from the tip to the base end of the tube main body constituting the overtube 10, and is disposed in both the first region T1 and the second region T2. ​​This shape variable body 38 is configured as a helical tube formed by winding a strip-shaped member in a helical shape along the longitudinal axis C on the outer circumferential side of the inner tube 32. The shape variable body 38 has flexibility in the bending direction and can be deformed following the shape of the overtube 10. For example, when the overtube 10 in a softened state is deformed into a curved shape or any other arbitrary shape, the shape variable body 38 also deforms following that shape.

[0065] The belt-shaped member constituting the spiral tube is made of stainless steel (SUS: Steel Use Stainless). Note that the belt-shaped member is not limited to being made of stainless steel, and any material that can be deformed to conform to the shape of the overtube 10 can be used. For example, the belt-shaped member may be made of plastic or the like. The thickness of the belt-shaped member is preferably 300 μm or less when the thickness D of the tube outer circumferential wall 16 of the overtube 10 in a softened state is 1 mm or less.

[0066] Next, the different configurations of the first region T1 and the second region T2 will be described. As shown in Fig. 2 and Fig. 3, the overtube 10 in this embodiment has different configurations of the first region T1 and the second region T2. ​​Below, the configuration of the first region T1 will be described first, and then the configuration of the second region T2 will be described.

[0067] The first region T1 is a region located on the base end side of the second region T2. ​​The length of the first region T1 in the longitudinal direction (direction along the longitudinal axis C, the same applies below) is configured to be longer than the length of the second region T2 in the longitudinal direction. Specifically, the length of the first region T1 in the longitudinal direction is at least 20 cm (centimeters, the same applies below), for example, 20 cm or more and 100 cm or less.

[0068] The first region T1 is switchable between a softened state (also referred to as a flexible state or a non-hardened state; equivalent to the "first state" of the present invention) in which air (an example of a "fluid") is supplied to the tube internal space S between the outer tube 30 and the inner tube 32 via the supply / discharge port 22, and a second state (also referred to as a hardened state or a rigid state; equivalent to the "second state" of the present invention) harder than the first state in which air is discharged from the tube internal space S. Specifically, the first region T1 has the following configuration.

[0069] As shown in FIG. 2, the first region T1 has the outer tube 30, the inner tube 32, and the shape variable body 38 as described above. Furthermore, the first region T1 is provided with a sheet material 40. The sheet material 40 is an intermediate layer disposed between the outer tube 30 and the inner tube 32, and is disposed so as to be able to contact the shape variable body 38. Specifically, the sheet material 40 is interposed between the outer tube 30 and the shape variable body 38, and has a cylindrical shape so as to surround the periphery of the shape variable body 38. The sheet material 40 is provided over the entire longitudinal direction of the first region T1. Note that, as described later, in this embodiment, the sheet material 40 is not provided in the second region T2. ​​Note that the sheet material 40 has flexibility so as to be deformable according to the shape of the overtube 10.

[0070] The sheet material 40 is made of resin such as urethane, for example. However, the present invention is not limited to this, and may be made of, for example, an aluminum-deposited film. An aluminum-deposited film is a film in which aluminum (aluminum foil) is vacuum-deposited (thermocompression-bonded) on the surface of a base film. By using an aluminum-deposited film as the sheet material 40, the rigidity of the sheet material 40 can be increased. In this case, examples of the base film include a film having heat sealability such as PET (Polyethylene terephthalate) or PE (polyethylene). In addition, the elastic modulus of the sheet material 40 is preferably higher than that of the outer tube 30 and the inner tube 32. The elastic modulus of the sheet material 40 is determined by the method described in JIS K7161 (tensile test) or a method conforming thereto. This allows the outer tube 30 and the inner tube 32 to be reinforced by the sheet material 40. That is, the tensile strength and tensile rigidity of the overtube 10 are increased by the sheet material 40. As a result, the forward movement of the overtube 10 in the softened state is improved. By using a combination of aluminum vapor deposition film or aluminum foil with various cloths and films, a material with the optimum elastic modulus can be selected.

[0071] The thickness of the sheet material 40 is preferably 300 μm or less, for example, when the thickness of the tube outer peripheral wall 16 of the overtube 10 in the softened state is set to 1 mm or less. However, from the viewpoint of rigidity, the sheet material 40 is preferably thicker than the outer tube 30 and the inner tube 32. Furthermore, when an aluminum vapor deposition film is used as the sheet material 40, the rigidity of the overtube 10 can be changed by changing the base film. As a result, the rigidity of the overtube 10 in the softened state can be tuned to a rigidity suitable for the insertion site (upper digestive tract or lower digestive tract) of the endoscope insertion portion 102.

[0072] The sheet material 40 has a first contact surface 40a on the side (inner peripheral surface side) facing the shape-variable body 38. The first contact surface 40a is a surface that can come into contact with the shape-variable body 38, and the entire surface is configured as a high-friction surface. That is, the sheet material 40 of this example is configured from a friction sheet material having a high-friction surface on the surface (first contact surface 40a) facing the shape-variable body 38. As a result, the first contact surface 40a of the sheet material 40 comes into contact with the shape-variable body 38 with high friction, and the first contact surface 40a restricts the movement of the shape-variable body 38 in the direction along the longitudinal axis C, making it possible to increase the shape retention of the shape-variable body 38.

[0073] The high-friction surface is formed, for example, by a resin layer formed by coating the inner peripheral surface of the sheet material 40 with a resin such as a urethane coat or a silica coat. The high-friction surface may also be formed by a rough surface formed with fine irregularities on the inner peripheral surface of the sheet material 40. This rough surface is formed by roughening the surface with a blasting process, a laser irradiation process, a chemical conversion treatment, etching, or the like. The high-friction surface may be formed by roughening the inner peripheral surface of the sheet material 40 and coating it with the resin, or may be formed by roughening the inner peripheral surface of the sheet material 40 with the resin.

[0074] Here, in this specification, the "high friction surface" refers to a surface having a higher friction coefficient than the surface that comes into contact with the shape-variable body 38 when the sheet material 40 is not interposed (in this example, the inner circumferential surface of the outer tube 30). In other words, the "high friction surface" generates a friction resistance that is higher than the friction resistance when the shape-variable body 38 and the outer tube 30 come into direct contact without the sheet material 40 being interposed. The friction coefficient of the "high friction surface" can be measured, for example, by the method described in JIS P8147:2010 or a method conforming thereto.

[0075] In addition, in this specification, "non-deformable" means that the shape of the shape-variable body 38 is fixed when the air in the tube internal space S is exhausted. In addition, in this specification, "frictional engagement" means that contact surfaces that come into contact with each other engage with each other with a frictional force. This frictional force is a frictional force (static frictional force) that occurs when the respective contact surfaces come into contact with each other in the radial direction of the overtube 10 when the overtube 10 is viewed from the direction along the longitudinal axis C. In addition, each contact surface is formed in a substantially circular shape when viewed from the direction of the longitudinal axis C.

[0076] In the present embodiment, as an example, the first contact surface 40a on the side (inner peripheral surface side) of the sheet material 40 facing the shape-variable body 38 is configured as a high friction surface, but the present invention is not limited to this, and the second contact surface 38a on the side (outer peripheral surface side) of the shape-variable body 38 facing the sheet material 40 may be configured as a high friction surface. In addition, both the first contact surface 40a of the sheet material 40 and the second contact surface 38a of the shape-variable body 38 may be configured as high friction surfaces. That is, it is sufficient that at least one of the first contact surface 40a of the sheet material 40 and the second contact surface 38a of the shape-variable body 38 is configured as a high friction surface.

[0077] In addition, in this embodiment, the high friction surface may be formed on the entirety of at least one of the first contact surface 40a and the second contact surface 38a, or may be formed on a part of either one of the contact surfaces. That is, the high friction surface may be formed on at least a part of either one of the contact surfaces. However, from the viewpoint of increasing the shape retention of the shape variable body 38, it is preferable that the high friction surface is formed on the entirety of either one of the contact surfaces, and more preferably, it is preferable that the high friction surface is formed on the entirety of both of the contact surfaces. In addition, from the viewpoint of ensuring the flexibility of the overtube 10 in the softened state, the gap between the shape variable body 38 and the sheet material 40 is preferably about 50 μm to 500 μm.

[0078] Furthermore, the sheet material 40 in the present embodiment is configured in a sheet shape with a smooth surface without cut portions such as cut holes or cut lines, but is not limited thereto, and the sheet material 40 may have cut portions provided therein as long as it can make the hardness of the first region T1 in the overtube 10 harder than the second region T2. ​​Furthermore, the sheet material 40 is not limited to being a single sheet material, and may be configured from a plurality of sheet materials.

[0079] Next, the configuration of the second region T2 will be described.

[0080] 3, the second region T2 is similar to the first region T1 in that it has an outer tube 30, an inner tube 32, and a shape-variable body 38. The second region T2 differs from the first region T1 in that the sheet material 40 is not interposed between the outer tube 30 and the shape-variable body 38. As a result, the second region T2 is configured as a region softer than the first region T1.

[0081] That is, in this embodiment, in order to configure the second region T2 of the overtube 10 as a region softer than the first region T1, the first region T1 of the overtube 10 is configured so that a sheet material 40 is interposed between the outer tube 30 and the shape-variable body 38, while the second region T2 is configured so that a sheet material 40 is not interposed between the outer tube 30 and the shape-variable body 38.

[0082] Furthermore, like the first region T1 described above, the second region T2 can be switched between a softened state (corresponding to the "first state" of the present invention) in which air is supplied to the tube internal space S between the outer tube 30 and the inner tube 32 via the supply and exhaust port 22, and a hardened state (corresponding to the "second state" of the present invention) in which air is exhausted from the tube internal space S and which is harder than the hardened state; however, due to the difference in the arrangement of the sheet material 40 described above, the hardness in each state of the second region T2 is configured to be softer than the hardness in each corresponding state of the first region T1.

[0083] Specifically, when the overtube 10 is in a hardened state (second state) (i.e., when the first region T1 and the second region T2 are in a hardened state), the second region T2 is configured to be softer than the first region. Also, when the overtube 10 is in a softened state (first state) (i.e., when the first region T1 and the second region T2 are in a softened state), the second region T2 is configured to be softer than the first region.

[0084] According to this configuration, the second region T2 is configured as a region softer than the first region T1 whether the overtube 10 is in a hardened state or a softened state. Therefore, for example, even when the endoscope insertion portion 102 is inserted through the overtube 10 in a hardened state and the endoscope insertion portion 102 is curved, the second region T2 is configured as a region softer than the first region T1, so that the curving motion is not significantly hindered by the overtube 10 in the hardened state, and a sufficient amount of curvature can be obtained.

[0085] Furthermore, when the overtube 10 and the endoscope insertion portion 102 in the softened state are moved forward and backward relative to one another, even if the amount of curvature of the endoscope insertion portion 102 derived from the tip of the overtube 10 is large, as shown in FIG. 4, the second region T2 is configured as a region softer than the first region T1, so that the overtube 10 can be smoothly pushed in, following the wall surface of the digestive tract, without getting caught on wrinkles that occur in the curved portion 106 of the endoscope insertion portion 102.

[0086] Here, the length of the second region T2 in the longitudinal direction is preferably 5 cm or more and 20 cm or less (more preferably 7 cm or more and 15 cm or less). The base end of the second region T2 is preferably provided at a position within 20 cm from the tip 10a of the overtube 10. The above length and position are preferably determined based on the angle length of the endoscope insertion portion 102 (the length from the tip of the endoscope insertion portion 102 to the base end of the bending portion 106) used in combination with the overtube 10. The angle length of the endoscope insertion portion 102 is, for example, 7 cm for an upper endoscope and 10 cm for a lower endoscope.

[0087] By setting the second region T2 to the above length and position, when the tip 10a of the overtube 10 and the tip of the endoscope insertion portion 102 are aligned in a state in which the endoscope insertion portion 102 is inserted through the overtube 10, the second region T2 is positioned in a region in which at least the bending portion 106 of the endoscope insertion portion 102 is positioned. As a result, even when the endoscope insertion portion 102 is retracted into the overtube 10 and the tip 10a of the overtube 10 and the tip of the endoscope insertion portion 102 are approximately aligned, the second region T2 is present in a position corresponding to the bending portion 106 of the endoscope insertion portion 102. Therefore, even when the endoscope insertion portion 102 is bent in a state in which the overtube 10 is overlapped with the bending portion 106 of the endoscope insertion portion 102, the bending movement is not significantly hindered by the overtube 10, so a sufficient amount of bending can be obtained, and the endoscope insertion portion 102 can be guided in a desired direction.

[0088] According to the overtube 10 configured as above, in the first region T1, when the air in the tube internal space S is discharged by the pump 26, the inner circumferential surface of the outer tube 30 is pressed against the shape-variable body 38 via the sheet material 40 and comes into close contact with it, and the outer circumferential surface of the inner tube 32 is pressed against the shape-variable body 38 and comes into close contact with it, thereby fixing the position of the shape-variable body 38. As a result, the first region T1 changes from a softened state (first state) to a hardened state (second state) which is harder than the softened state. At that time, the shape-variable body 38 and the sheet material 40 come into close contact with each other via a high friction surface and frictionally engage with each other. This restricts the movement of the shape-variable body 38 in the direction along the longitudinal axis C, and the shape (e.g., curved shape) of the shape-variable body 38 is held undeformable, thereby enhancing the shape retention of the first region T1 in the hardened state. Conversely, when air is allowed to flow into the tube internal space S after the air has been discharged, the shape of the shape-variable body 38 is released, and the first region T1 changes from a hardened state to a softened state.

[0089] On the other hand, in the second region T2, when the air in the tube internal space S is discharged by the pump 26, the inner circumferential surface of the outer tube 30 is pressed against and tightly adheres to the shape-variable body 38, and the outer circumferential surface of the inner tube 32 is pressed against and tightly adheres to the shape-variable body 38, thereby fixing the position of the shape-variable body 38. As a result, the second region T2 changes from a softened state (first state) to a hardened state (second state) which is harder than the softened state. At that time, since the sheet material 40 is not provided in the second region T2, the second region T2 which has changed to the hardened state is softer than the hardened state of the first region T1. Conversely, when air is allowed to flow into the tube internal space S from a state in which air has been discharged, the second region T2 changes from the hardened state (second state) to the softened state (first state). Since the sheet material 40 is not provided in the second region T2 in the softened state, the second region T2 is also softer than the softened state of the first region T1.

[0090] In this way, the second region T2 is configured to be softer in both the hardened and softened states than the first region T1 in the corresponding states (i.e., the hardened and softened states). This improves the insertability of the tip side of the overtube 10 into the digestive tract (particularly the upper digestive tract). This allows the endoscope insertion portion 102 to be stably held by the first region T1 in both states, while the endoscope insertion portion 102 can be guided in a desired direction by the second region T2. ​​As a result, when a pylorus passing procedure, which will be described later, is performed, it becomes possible to easily move the overtube 10 and the endoscope insertion portion 102 inside the body.

[0091] <Pyloric Transurethra Procedure> As an example of a procedure using the overtube 10 of this embodiment, a procedure in which the endoscope insertion portion 102 passes through the pylorus between the stomach and the small intestine (pylorus passing procedure) will be described. Note that the pylorus passing procedure is only one example, and other procedures that partially include the same operations as the pylorus passing procedure can be realized by combining the same steps as the pylorus passing procedure.

[0092] [The first case of transpyloric procedure] A first example of the pylorus passing procedure will be described with reference to Figs. 5 and 6. Fig. 5 is a flow chart showing the procedure of the first example of the pylorus passing procedure. Fig. 6 is an explanatory diagram for explaining the first example of the pylorus passing procedure. Note that, at the start of this flow chart, the overtube 10 is in a softened state. The same applies to a second example described later.

[0093] (Step S10: Insertion step) First, with the endoscope insertion portion 102 inserted through the overtube 10, the endoscope insertion portion 102 and the overtube 10 are inserted into the stomach 200 from the mouth of the subject.

[0094] (Step S12: Alignment step) Next, as shown in FIG. 6, the endoscope insertion part is inserted from the tip opening of the overtube 10. The endoscope insertion portion 102 is aligned to a position where the tip portion 104 of the endoscope 102 is exposed. This alignment is performed by moving the endoscope insertion portion 102 in the base end direction C2 (proximal side) relative to the overtube 10, or by moving the overtube 10 in the tip direction C1 (distal side) relative to the endoscope insertion portion 102.

[0095] The insertion step may be performed after the positioning step. By performing the insertion step after the positioning step, the overtube 10 and the endoscope insertion part 102 can be inserted into the stomach 200 while obtaining a field of view forward in the insertion direction through the illumination window and the observation window at the tip of the endoscope insertion part 102.

[0096] (Step S14: Pylorus Passing Step) Next, as shown in FIG. 6 VIB, the endoscope insertion portion 102 and the overtube 10 are put together. The endoscope insertion section 102 and the overtube 10 are pushed into the pylorus 202, and the endoscope insertion section 102 and the overtube 10 are passed through the pylorus 202. Specifically, the endoscope insertion section 102 and the overtube 10 are pushed in together while bending the bending section 106 so that the tip end portion 104 of the endoscope insertion section 102 is guided toward the pylorus 202. At this time, since the second region T2 of the overtube 10 in the softened state is configured as a region softer than the first region T1, the second region T2 can be bent following the bending motion of the endoscope insertion section 102. Therefore, the bending motion of the endoscope insertion section 102 is not significantly hindered by the second region T2 (i.e., the degree of freedom of the bending motion of the endoscope insertion section 102 is not significantly restricted), the endoscope insertion section 102 and the overtube 10 can be pushed in together while the tip end portion 104 of the endoscope insertion section 102 is guided toward the pylorus 202 by the bending motion of the endoscope insertion section 102. As a result, it becomes possible to pass the endoscope insertion portion 102 and the overtube 10 through the pylorus 202 easily and stably.

[0097] (Step S16: Pull-in step) Next, as shown in FIG. 6(VIC), the endoscope insertion portion 102 and the overtube 10 are put together. The overtube 10 is pulled in at the same time, and a part of the overtube 10 is moved toward the small bay portion 204 to reduce the slack of the overtube 10. Here, after the pylorus passing step is performed, as shown in FIG. 6 VIB, a large slack is generated in a part (middle part) of the overtube 10 inside the stomach 200. If such slack is generated in the overtube 10, it may cause an obstacle when the overtube 10 and the endoscope insertion part 102 are pushed further into the body. Therefore, it is desirable to make the overtube 10 and the endoscope insertion part 102 in a state close to a straight line at this stage so that the overtube 10 and the endoscope insertion part 102 can be pushed further into the body. Therefore, after the pylorus passing step is performed, a pulling-in step is performed to eliminate the slack of the overtube 10 generated inside the stomach 200. As a result, the overtube 10 inside the stomach 200 is in a state where the slack is eliminated (stretched state) compared to before the pulling-in step is performed.

[0098] (Step S18: Hardening step) Next, the overtube 10 is hardened. Specifically, the pump 26 is operated to discharge air from the tube internal space S through the supply and discharge port 22. As a result, in the first region T1, the outer tube 30 and the inner tube 32 are pressed against the shape-variable body 38, which is deformed to match the shape of the overtube 10. Then, the inner circumferential surface of the outer tube 30 is pressed against the shape-variable body 38 via the sheet material 40 and comes into close contact with it, and the outer circumferential surface of the inner tube 32 is pressed against the shape-variable body 38 and comes into close contact with it, thereby fixing the position of the shape-variable body 38. As a result, the first region T1 changes from a softened state to a hardened state. At that time, the shape-variable body 38 and the sheet material 40 come into close contact with each other via a high friction surface and frictionally engage with each other. As a result, the shape of the shape-variable body 38 (for example, a curved shape) is maintained in an undeformable state, so that the first region T1 hardens in a shape corresponding to the shape-variable body 38.

[0099] Furthermore, when the pump 26 is operated to discharge the air from the tube internal space S through the supply / discharge port 22, the inner circumferential surface of the outer tube 30 is pressed against and tightly adheres to the shape-variable body 38 in the second region T2, and the outer circumferential surface of the inner tube 32 is pressed against and tightly adheres to the shape-variable body 38, thereby fixing the position of the shape-variable body 38. As a result, the second region T2 changes from a softened state to a hardened state that is harder than the softened state. At that time, since the sheet material 40 is not provided in the second region T2, the second region T2 that has changed to the hardened state is softer than the hardened state of the first region T1.

[0100] Therefore, when air is discharged from the tube internal space S through the supply / discharge port 22, the first region T1 of the overtube 10 becomes hardened, and the second region T2 located distal to the first region T1 becomes softer than the hardened state of the first region T1. This makes it possible for the first region T1 to stably hold the endoscope insertion portion 102 without it swinging inside the body, and for the second region T2 to guide the endoscope insertion portion 102 in a desired direction. As a result, the insertability of the endoscope insertion portion 102 is improved.

[0101] Thereafter, the curved portion 106 of the endoscope insertion portion 102 is protruded forward from the tip opening of the overtube 10, and a treatment tool (not shown) is led forward from the treatment tool lead-out port of the tip portion 104 to start treatment such as ESD (Endoscopic Submucosal Dissection). At this time, since the insertability of the endoscope insertion portion 102 is improved by the overtube 10 in a hardened state, the tip portion 104 can be positioned at an appropriate treatment position, and as a result, it becomes possible to perform an appropriate treatment on the site to be treated (lesion, etc.).

[0102] In the above-mentioned first example, the case where the overtube 10 that has passed through the pylorus 202 is hardened only once and the treatment of the site to be treated is described, but the present invention is not limited thereto. For example, the operation of treating the site to be treated by gradually advancing the endoscope insertion part 102 and the overtube 10 while changing the overtube 10 that has passed through the pylorus 202 between the softened state and the hardened state multiple times may be performed. The operation in this case includes a step of advancing the endoscope insertion part 102 relatively to the overtube 10 in a state where the overtube 10 through which the endoscope insertion part 102 is inserted is in a hardened state (endoscope insertion part advancing step), and a step of advancing the overtube 10 relatively to the endoscope insertion part 102 in a state where the overtube 10 through which the endoscope insertion part 102 is inserted is in a softened state (overtube advancing step). The same applies to the second example described later.

[0103] [Second example of transpyloric procedure] A second example of the pylorus-passing procedure will be described with reference to Fig. 7 and Fig. 8. Fig. 7 is a flow chart showing the procedure of the second example of the pylorus-passing procedure. Fig. 8 is an explanatory diagram for explaining the second example of the pylorus-passing procedure.

[0104] (Step S20: Insertion step) First, with the endoscope insertion portion 102 inserted through the overtube 10, the endoscope insertion portion 102 and the overtube 10 are inserted into the stomach 200 from the mouth of the subject.

[0105] (Step S22: Endoscope passing through the pylorus) 8A, the endoscope insertion portion 102 is pushed in, and at least a part of the bending portion 106 of the endoscope insertion portion 102 passes through the pylorus 202. At this time, the endoscope insertion portion 102 is pushed in while bending the bending portion 106 so that the tip of the endoscope insertion portion 102 is guided toward the pylorus 202, while ensuring a field of view through the observation window and illumination window at the tip of the endoscope insertion portion 102.

[0106] (Step S24: Overtube passing through the pylorus step) Next, as shown in VIIIB of Fig. 8, the overtube 10 is pushed to pass through the pylorus 202. At that time, since the second region T2 of the overtube 10 in the softened state is configured as a region softer than the first region T1, even if the overtube 10 is pushed along the endoscope insertion part 102 that has already passed through the pylorus 202, the overtube 10 can be pushed smoothly, following the wall surface of the digestive tract, without getting caught on wrinkles generated in the curved part 106 of the endoscope insertion part 102 (see Fig. 4).

[0107] (Step S26: Alignment step) Next, the endoscope insertion part 102 is aligned to a position where the tip 104 is exposed from the tip of the overtube 10. This alignment is performed by moving the endoscope insertion part 102 in the base end direction C2 (proximal side) relative to the overtube 10, or by moving the overtube 10 in the tip direction C1 (distal side) relative to the endoscope insertion part 102. Note that if the tip of the overtube 10 and the tip part 104 of the endoscope insertion part 102 have already been aligned in the overtube pylorus passing step, the alignment step can be omitted. Also, if the endoscope insertion part 102 is inserted deep inside the body (to the duodenum), the alignment step does not necessarily have to be performed.

[0108] (Step S28: Pull-in step) 8, the endoscope insertion portion 102 and the overtube 10 are pulled in together, and a part of the overtube 10 is moved toward the small bay portion 204 to reduce slack in the overtube 10. As a result, the overtube 10 in the stomach 200 is in a state where slack is eliminated (stretched state) compared to before the pulling-in step is performed, similar to the first example described above.

[0109] (Step S30: Hardening step) Next, the overtube 10 is hardened. Specifically, the pump 26 is operated to discharge air from the tube internal space S through the supply and discharge port 22. As a result, similar to the first example described above, when the air from the tube internal space S is discharged through the supply and discharge port 22, the first region T1 is hardened, and the second region T2 located on the distal side of the first region T1 is softer than the hardened state of the first region T1. As a result, the first region T1 can hold the endoscope insertion portion 102 in a stable state without shaking inside the body, and the second region T2 can guide the endoscope insertion portion 102 in a desired direction. As a result, the insertability of the endoscope insertion portion 102 is improved.

[0110] (Step S32: Insertion step) Next, as shown in FIG. 8D, the endoscope insertion portion 102 is pushed into the overtube 10, and the endoscope insertion portion 102 is inserted deep inside the body.

[0111] Thereafter, the curved portion 106 of the endoscope insertion portion 102 is protruded forward from the tip opening of the overtube 10, and a treatment tool (not shown) is led forward from the treatment tool lead-out port of the tip portion 104 to start treatment such as ESD (Endoscopic Submucosal Dissection). At this time, since the insertability of the endoscope insertion portion 102 is improved by the overtube 10 in a hardened state, the tip portion 104 can be positioned at an appropriate treatment position, and as a result, it becomes possible to perform an appropriate treatment on the site to be treated (lesion, etc.).

[0112] As described above, according to the first embodiment, the overtube 10 includes a first region T1 that can be switched between a softened state (first state) in which air is supplied to the tube internal space S between the outer tube 30 and the inner tube 32 via the supply / discharge port 22 and a hardened state (second state) that is harder than the softened state in which air is discharged from the tube internal space S, and a second region T2 that is located distal to the first region T1 and is configured to be softer than the hardened state of the first region T1. As a result, when the first region T1 is in the hardened state, the first region T1 makes it possible to hold the endoscope insertion portion 102 in a stable state inside the body, and the second region T2 makes it possible to obtain a sufficient amount of bending without significantly hindering the bending motion of the endoscope insertion portion 102.

[0113] Furthermore, according to the first embodiment, in the above-mentioned configuration, the softened state of the second region T2 is configured to be softer than the softened state of the first region T1. As a result, even if the amount of bending of the endoscope insertion portion 102 derived from the tip of the overtube 10 in the softened state is large, the overtube 10 can be smoothly pushed in while following the wall surface of the digestive tract without being affected by wrinkles or the like generated in the bending portion 106 of the endoscope insertion portion 102.

[0114] Therefore, according to the first embodiment, the insertability of the tip side of the overtube 10 into the digestive tract (particularly the upper digestive tract) is improved. As a result, it becomes possible to easily move the endoscope insertion part 102 and the overtube 10 inside the body, and it becomes possible to easily and stably guide the endoscope insertion part 102 in a desired direction using the overtube 10. In particular, the above effect becomes remarkable when the above-mentioned pylorus passing procedure is performed.

[0115] Second Embodiment Fig. 9 is a schematic cross-sectional view showing the configuration of the overtube 10 of the second embodiment. Fig. 10 is a planar development of the sheet material 50 provided in the overtube 10 of the second embodiment. The bottom part of Fig. 10 shows a graph of the hardness of the overtube 10 in the second embodiment. Fig. 11 is an external view of the overtube 10 of the second embodiment with the outer tube 30 omitted.

[0116] The overtube 10 of the second embodiment is similar to that of the first embodiment, except for the arrangement and shape of the sheet material 50. The following describes the configurations that are different from the first embodiment.

[0117] 9, in the second embodiment, a sheet material 50 is disposed in both a first region T1 and a second region T2 of the overtube 10. The sheet material 50 has different shapes in the first region T1 and the second region T2 in order to configure the second region T2 as a region softer than the first region T1.

[0118] 10 and 11, the region of the sheet material 50 corresponding to the first region T1 is formed in a sheet shape with a smooth surface without cut portions 52, while the region corresponding to the second region T2 is provided with a plurality of cut portions 52. In this example, of the plurality of cut portions 52 provided in the region corresponding to the second region T2, most of the cut portions 52 are formed as elongated cut holes in the circumferential direction (the vertical direction in FIG. 10), and the remaining cut portions 52 are formed as circular cut holes.

[0119] All or some of the cuts 52 may be formed of elongated cut holes in the direction along the longitudinal axis C (horizontal direction in FIG. 10), or may be formed of circular or elliptical cut holes. Also, each cut 52 may be formed of cut holes of other shapes. Each cut 52 may be formed of a mixture of holes of a plurality of shapes as in the example shown in FIG. 10, or may be formed of only holes of a single shape.

[0120] 10, in a plan view when the sheet material 50 is developed into a plane, the multiple cut portions 52 are arranged according to a regular pattern. Specifically, multiple cut portion rows 54 each consisting of multiple cut portions 52 arranged at equal intervals in the circumferential direction are arranged at equal intervals along the longitudinal direction of the sheet material 50 (the direction along the longitudinal axis C), and are arranged in a staggered manner such that the cut portion rows 54 arranged in the longitudinal direction of the sheet material 50 are shifted from each other in the circumferential direction.

[0121] As long as the second region T2 of the overtube 10 can be configured as a region softer than the first region T1, the shape and arrangement of the cuts 52 provided in the region corresponding to the first region T1 of the sheet material 50 are not limited to those in this example. Furthermore, at least a part, most, substantially all, or all of the cuts 52 may be arranged according to a random pattern or an irregular pattern, not limited to the regular pattern as in this example. The "regular pattern" means that the circumferential pitch and the longitudinal pitch (direction along the longitudinal axis C) of the cuts 52 are regular, and includes not only the case where the pitches are equally spaced, but also the case where the pitches vary but vary periodically. Therefore, even if the shapes or sizes of some of the cuts 52 are different, the regular pattern is included as long as the pitches are regular.

[0122] According to the second embodiment, since a plurality of cut portions 52 are provided in the region of the sheet material 50 corresponding to the second region T2, the second region T2 of the overtube 12 is configured as a region softer than the first region T1, as shown in the lower graph of Fig. 10. This makes it possible to easily move the overtube 10 and the endoscope insertion portion 102 inside the body, as in the first embodiment. As a result, it becomes possible to easily and stably guide the endoscope insertion portion 102 in a desired direction using the overtube 10.

[0123] In the second embodiment, the above-mentioned rows of cut portions 54 are arranged at equal intervals along the longitudinal direction of the sheet material 50 (the direction along the longitudinal axis C), so that the region of the sheet material 50 corresponding to the first region T1 has a certain degree of flexibility along the longitudinal direction of the sheet material 50. In this specification, "constant" does not mean completely constant, but means substantially constant (for example, a variation within a range of plus or minus 10% is allowed).

[0124] [Modification of the second embodiment] A modification of the second embodiment will now be described.

[0125] <First Modification> 12 is a plan view of the sheet material 50A according to the first modification. As shown in FIG. 12, in the first modification, each of the cut portions 52A of the sheet material 50A provided in the second region T2 of the overtube 10 is formed by a cut line provided in the circumferential direction. Each of the cut portions 52A is arranged according to a regular pattern similar to that of the second embodiment. That is, a plurality of cut portion rows 54A consisting of a plurality of cut portions 52A arranged at equal intervals in the circumferential direction are arranged at equal intervals along the longitudinal direction (direction along the longitudinal axis C) of the sheet material 50A, and are arranged in a staggered manner such that the cut portion rows 54A arranged in the longitudinal direction of the sheet material 50A are shifted from each other in the circumferential direction.

[0126] According to the cut portion 52A of the first modified example, the second region T2 of the overtube 10 can be configured as a region softer than the first region T1, and the same effects as those of the second embodiment can be obtained.

[0127] <Second Modification> FIG. 13 is a planar view of a sheet material 50B according to the second modification. As shown in FIG. 13, in the second modification, each cut portion 52B of the sheet material 50B provided in the second region T2 of the overtube 10 is configured by a cut line having a shape different from that of the first modification. The cut lines constituting the cut portions 52B of the second modification are formed by combining straight lines or curved lines in a plurality of directions. As an example, the cut portion 52B provided in the center portion of the circumferential direction (vertical direction in FIG. 13) of the sheet material 50B is bent toward the base end side (right side in FIG. 14) at the center portion in the circumferential direction, and both ends are formed in a straight line along the circumferential direction. In addition, a cut portion row 54B consisting of a plurality of cut portions 52B arranged at equal intervals in the circumferential direction is arranged at equal intervals along the longitudinal direction (direction along the longitudinal axis C) of the sheet material 50B.

[0128] According to the cut portion 52B of the second modification, the second region T2 of the overtube 10 can be configured as a region softer than the first region T1, and the same effects as those of the second embodiment can be obtained.

[0129] <Third Modification> Fig. 14 is a planar view of a sheet material 50C according to a third modified example. As shown in Fig. 14, in the third modified example, the sheet material 50C is divided into a first divided sheet material 56A arranged in the first region T1 and a second divided sheet material 56B arranged in the second region T2. ​​In this manner, the sheet material 50C may be formed of a plurality of divided sheet materials divided into regions.

[0130] The cut portion 52C and the cut portion row 54C of the third modified example are similar to the cut portion 52 and the cut portion row 54 of the second embodiment. Of course, the sheet material of the other modified examples may be formed of a plurality of divided sheet materials, as in the third modified example.

[0131] <Fourth Modification> Fig. 15 is a planar development of a sheet material 50D according to the fourth modified example. The bottom part of Fig. 15 shows a graph of the hardness of the overtube 10 in the fourth modified example.

[0132] In the fourth modified example shown in FIG. 15, a plurality of cut portions 52D provided in the second region T2 of the sheet material 50D have the same shape as the cut portions 52 in the second embodiment.

[0133] In the fourth modification, a plurality of cut-out rows 54D, each of which is made up of a plurality of cut-outs 52D arranged at equal intervals in the circumferential direction, are arranged in the longitudinal direction (direction along the longitudinal axis C) of the sheet material 50D, and the pitch P, which is the interval between each of the cut-out rows 54D in the longitudinal direction of the sheet material 50D, gradually decreases toward the distal end direction C1. Therefore, the region of the sheet material 50D corresponding to the second region T2 gradually becomes softer toward the distal end direction C1. As a result, as shown in the graph in the lower part of FIG. 15, the second region T2 of the overtube 10 is configured as a region that is softer than the first region T1 and gradually becomes softer toward the distal end direction C1 (gradation-like change region).

[0134] Moreover, the length of the second region T2 of the overtube 10 in the longitudinal direction (the direction along the longitudinal axis C) is preferably 5 cm or more and 50 cm or less. Moreover, the base end of the second region T2 is preferably provided at a position within 50 cm from the tip end of the overtube 10. Note that in the fifth and sixth modified examples described later, the same length and position are preferable.

[0135] According to the fourth modification, the second region T2 of the overtube 10 becomes gradually softer toward the distal end direction C1, and the distal end side of the second region T2 is configured to be softer than the proximal end side of the second region T2. ​​This makes it possible to push the overtube 10 into the endoscope insertion portion 102 more easily and smoothly when the overtube 10 is in a softened state, compared to when the second region T2 has a certain degree of flexibility in the longitudinal direction.

[0136] Although the cut portion 52D of the fourth modified example is formed by applying the cut portion 52A of the second embodiment, the present invention is not limited to this example, and other modified examples may be applied.

[0137] <Fifth Modification> Fig. 16 is a planar development of a sheet material 50E according to the fifth modified example. The bottom part of Fig. 16 shows a graph of the hardness of the overtube 10 in the fifth modified example.

[0138] In the fifth modified example shown in FIG. 16, a plurality of cut portions 52E provided in the second region T2 of the sheet material 50E have the same shape as the cut portions 52 in the second embodiment.

[0139] In the fifth modified example, the region of the sheet material 50E corresponding to the second region T2 is divided into a plurality of regions (two in this example) having different hardnesses. Specifically, the region of the sheet material 50E corresponding to the second region T2 has a tip region R1 (corresponding to the "first intermediate layer" of the present invention) provided on the tip side, and a base region R2 (corresponding to the "second intermediate layer" of the present invention) provided on the base side.

[0140] A plurality of cuts 52E are provided in each of the distal region R1 and the proximal region R2. In each region, the pitch of the cut row 54E in the longitudinal direction (direction along the longitudinal axis C) is constant, whereas the pitch Pa of the cut row 54E in the distal region R1 is smaller than the pitch Pb of the cut row 54E in the proximal region R2. Therefore, in the region corresponding to the second region T2 of the sheet material 50E, the distal region R1 is softer than the proximal region R2. As a result, as shown in the graph in the lower part of FIG. 16, the second region T2 of the overtube 10 is configured as a region that is softer than the first region T1 and is softer on the distal side than the proximal side.

[0141] According to the fifth modification, the distal end side of the second region T2 is configured to be softer than the proximal end side. As a result, similar to the fourth modification, when the overtube 10 is in a softened state, it becomes possible to push the overtube 10 into the endoscope insertion portion 102 more easily and smoothly than when the second region T2 has a constant hardness in the longitudinal direction.

[0142] In the fifth modified example, the distal region R1 and the proximal region R2 of the second region T2 may be made of sheet materials (split sheet materials) having different hardnesses. The same applies to a sixth modified example described later.

[0143] In addition, in the fifth modified example, the hardness of the second region T2 of the overtube 10 changes in two stages. However, this is not limited to this, and the hardness may change in multiple stages, as in the sixth modified example described below.

[0144] <Sixth Modification> Fig. 17 is a planar development of a sheet material 50F according to the sixth modified example. The bottom part of Fig. 17 shows a graph of the hardness of the overtube 10 in the sixth modified example.

[0145] In the sixth modified example shown in FIG. 17, a plurality of cut portions 52F provided in the second region T2 of the sheet material 50F have the same shape as the cut portions 52 in the second embodiment.

[0146] In the sixth modified example, a cutout group 58 is formed by a plurality of (five in this example) cutout rows 54F. The pitch P1 of each cutout row 54F in each cutout group 58 is constant, whereas the pitch P2 between each cutout group 58 gradually decreases toward the distal end direction C1. Therefore, the region corresponding to the second region T2 of the sheet material 50F becomes softer in a step-like manner toward the distal end direction C1. As a result, as shown in the graph in the lower part of FIG. 17, the second region T2 of the overtube 10 is configured as a region that is softer than the first region T1 and that becomes softer in a step-like manner toward the distal end direction C1 (step-like change region).

[0147] According to the sixth modification, the second region T2 of the overtube 10 becomes softer in a step-like manner toward the distal end direction C1, and the distal end side of the second region T2 is configured to be softer than the proximal end side. As a result, as in the fourth modification, when the overtube 10 is in a softened state, it becomes possible to easily and smoothly push the overtube 10 into the endoscope insertion portion 102, compared to a case in which the second region T2 has a constant hardness in the longitudinal direction.

[0148] [Overtube bending evaluation] Next, the results of an evaluation of the degree of bending of the overtube are described. In this evaluation, the endoscope insertion part was inserted into the overtube, and the tip of the endoscope insertion part was made to almost coincide with the tip of the overtube (the bending part of the endoscope insertion part was overlapped with the overtube), and the difference in the amount of bending of the overtube was evaluated when the endoscope insertion part was bent.

[0149] FIG. 18 is a diagram showing the evaluation results of the degree of bending of the overtube. In FIG. 18, "Example 1", "Example 2", and "Example 3" in the first to third rows excluding the item column are evaluations performed using the overtubes of the first embodiment, the second embodiment, and the first modified example, respectively. "Comparative Example" in the fourth row corresponds to the above-mentioned conventional technology, and is a sheet material having a smooth surface without cuts arranged over the entire longitudinal direction of the tube body constituting the overtube (that is, a sheet material is arranged in the first region T1 and the second region T2 to make the hardness of the first region T1 and the second region T2 equal). In addition, "Endoscope" in the fifth row shows the results of bending the endoscope insertion part used in each evaluation alone for reference. Note that the overtube used in this evaluation is an overtube with the outer tube removed for convenience of evaluation.

[0150] 18, in the "Comparative Example," the amount of bending of the overtube is smaller than the amount of bending when the endoscope insertion portion is bent alone. This is because even if the endoscope insertion portion is bent, the overtube is restrained by the sheet material arranged in the area corresponding to the second area T2, and does not bend sufficiently.

[0151] In contrast, in "Example 1", the amount of bending of the overtube was greater than in the "Comparative Example", and it was possible to obtain an amount of bending roughly equivalent to that obtained when the endoscope insertion portion was bent alone, confirming the effectiveness of the configuration in which no sheet material is provided in the area corresponding to the second area T2.

[0152] Furthermore, it was possible to obtain a bending amount approximately equal to that of "Example 1" with the overtube of "Example 2," confirming the effectiveness of the configuration of providing multiple cut portions in the area corresponding to the second area T2 of the sheet material.

[0153] Moreover, for the overtube of "Example 3", the cut portion provided in the sheet material is configured with a different shape (cut line) than in "Example 2". In "Example 3", the amount of curvature of the overtube is smaller than in "Example 1" and "Example 2", but the amount of curvature is larger than in the "Comparative Example", and it was confirmed that a certain degree of effect can also be obtained in "Example 3".

[0154] Fig. 19 is a graph showing the results of measuring the hardness of the second region T2 of the overtube. The measurement was performed using a force gauge to measure the hardness (bending rigidity) of the overtube when the tip of the overtube was pressed 25 mm in a direction perpendicular to the longitudinal direction (direction along the longitudinal axis C) with a position 70 mm from the tip of the overtube as a fulcrum. In Fig. 19, "Example 1", "Example 2", "Example 3", and "Comparative Example" use the same overtube as the evaluation results shown in Fig. 18.

[0155] 19, the bending rigidity of the overtube in the "Comparative Example" was 2 N (Newton, the same applies below), whereas the bending rigidity of the overtube in the "Example 1" was 0.56 N, in the "Example 2" it was 0.61 N, and in the "Example 3" it was 0.9 N.

[0156] In this way, it was confirmed that in "Example 1" and "Example 2", the bending stiffness of the second region T2 was about 1 / 4 lower than that of the "Comparative Example", and sufficient effects were obtained. Also, in "Example 3", the bending stiffness of the second region T2 was about 1 / 2 lower than that of the "Comparative Example", and a certain degree of effect was obtained.

[0157] 〔effect〕 As described above, according to each embodiment (including modified examples, the same applies below), the hardness of the overtube 10 can be changed between a hardened state and a softened state, and in either state, the second region T2 of the overtube 10 is configured as a region softer than the first region T1. This improves the insertability of the tip side of the overtube 10 into the digestive tract (particularly the upper digestive tract). As a result, it becomes possible to easily perform the movement operation of the overtube 10 and the endoscope insertion portion 102 inside the body, and it becomes possible to easily and stably guide the endoscope insertion portion 102 in a desired direction using the overtube 10.

[0158] 〔others〕 In each of the above-described embodiments, a configuration in which the sheet material 40, 50 (including 50A to 50F, the same applies below) is interposed between the outer tube 30 and the shape-variable body 38 has been shown as one of the preferred aspects, but the present invention is not limited thereto and may be arranged between the outer tube 30 and the inner tube 32 at a position where the sheet material 40 can contact the shape-variable body 38. For example, as in another configuration example of the overtube 10 of the first embodiment shown in FIG. 20, the sheet material 40 may be interposed between the inner tube 32 and the shape-variable body 38. In this case, it is sufficient that at least a part of at least one of the contact surfaces of the inner tube 32 and the shape-variable body 38 facing each other is configured as a high-friction surface.

[0159] In addition, in each of the above-described embodiments, the intermediate layer provided between the outer tube 30 and the inner tube 32 is configured with the sheet material 40, 50, but this is not limited to the above and the intermediate layer may be configured with a linear member or a linear member. In addition, the sheet material 40, 50 is not limited to a single sheet formed into a cylindrical shape and may be configured with, for example, a cylindrical body having a C-shaped cross section perpendicular to the longitudinal axis C, or may be configured with a plurality of strip-shaped sheets that are elongated in the direction along the longitudinal axis C and arranged in the circumferential direction.

[0160] In each of the above-described embodiments, the configurations (arrangement or shape) of the sheet materials 40, 50 provided in the overtube 10 are made different between the first region T1 and the second region T2 to make the second region T2 softer than the first region T1, but in addition to this, or instead of this, the winding pitch (spiral pitch) of the strip-shaped member of the helical tube that constitutes the shape-variable body 38 may be made different between the first region T1 and the second region T2. ​​Even in this case, the second region T2 of the overtube 10 can be made softer than the first region T1.

[0161] In addition, in each of the above-described embodiments, the shape-variable body 38 is preferably configured as a spiral tube, but the present invention is not limited to this, and any known configuration may be applied as long as it is capable of deforming in accordance with the shape of the overtube 10. For example, the joint ring member disclosed in the above-described Patent Document 1 may be applied as the shape-variable body 38. Note that, since the joint ring member is known, detailed description thereof will be omitted here.

[0162] In addition, in each of the above-described embodiments, an example has been shown in which the endoscope insertion portion 102 is used as a medical instrument guided by the overtube of the present invention, but the present invention is not limited to this, and can also be applied to, for example, medical treatment tools such as manipulators.

[0163] Although the examples of the overtube according to the present invention have been described above, the present invention may be improved or modified in several ways without departing from the gist of the present invention. [Explanation of symbols]

[0164] 1 Endoscopic device 10 Overtube 10a Tip 10b Proximal end 14 Passage 16 Tube outer wall 18 Tip cap 20 Base end cap 22 Supply and exhaust port 24 Fluid supply and discharge tube 26 Pump 30 Outer tube 32 Inner tube 38 Variable Shape 40 Sheet material 50 Sheet material 50A sheet material 50B Sheet material 50C sheet material 50D sheet material 50E Sheet material 50F Sheet material 52 Notch 52A Notch 52B Cutout 52C Cutout 52D Cutout 52E Notch 52F Cutout 54A Cutout row 54B Cutout row 54C Cutout row 54D Cutout row 54E Cutout row 54F Cutout row 56A First division sheet material 56B Second division sheet material 58 Cutout Group 100 Endoscope 102 Endoscope insertion part 104 Tip 104a Tip surface 106 Curved section 108 Soft part 110 Handheld operation unit 200 Stomach 202 Pylorus 204 Small bay area C Longitudinal axis C1 Tip direction C2 proximal direction T1 1st area T2 2nd area Pitch Pa Pitch Pb Pitch P1 Pitch P2 Pitch R1 Tip region R2 proximal region S space (internal space of tube)

Claims

1. An overtube having an insertion passage through which a medical instrument can be inserted, a supply / discharge port located on the base end side for supplying and discharging a fluid; a first region located distally of the supply / discharge port and including a flexible outer tube, a flexible inner tube, and a deformable shape-variable body provided between the outer tube and the inner tube; a second region located distally of the first region and including the outer tube and the inner tube; the first region is switchable between a first state in which the fluid is supplied to a space between the outer tube and the inner tube via the supply / discharge port, and a second state in which the fluid is discharged and which is harder than the first state, the second region is softer than the first region in the second state; Overtube.

2. the second region is softer than the first region in the first state; The overtube according to claim 1 .

3. A distal end side of the second region is softer than a proximal end side of the second region. The overtube according to claim 2 .

4. The second region includes the shape-variable body, the second region is switchable between the first state in which a fluid is supplied to a space between the outer tube and the inner tube via the supply / discharge port, and the second state in which the fluid is discharged. The overtube according to claim 1 .

5. the first state of the second region is softer than the first state of the first region; the second state of the second region is softer than the second state of the first region; The overtube according to claim 4 .

6. the first region has an intermediate layer provided between the outer tube and the inner tube and capable of contacting the deformable body; In the second state, a first contact surface provided on the shape-variable body comes into contact with a second contact surface provided on the intermediate layer and facing the first contact surface, thereby hardening the first region. The overtube according to claim 1 .

7. the second region includes an intermediate layer having a different composition than the intermediate layer of the first region; The overtube according to claim 6 .

8. The intermediate layer in the second region has a certain degree of flexibility along the longitudinal direction. The overtube according to claim 7.

9. The intermediate layer of the second region is softer at a distal end than at a proximal end. The overtube according to claim 7.

10. The intermediate layer of the second region has a first intermediate layer provided on a distal end side and a second intermediate layer provided on a proximal end side, the first intermediate layer is softer than the second intermediate layer; The overtube according to claim 9 .

11. The intermediate layer in the second region becomes gradually softer toward the tip side. The overtube according to claim 9 .

12. the intermediate layer is formed of a sheet material provided from the first region to the second region, The sheet material in the second region is provided with a cut portion. The overtube according to claim 7.

13. The sheet material in the first region is configured with a smooth surface. The overtube according to claim 12.

14. At least a portion of one of the first contact surface and the second contact surface includes a high friction surface. The overtube according to any one of claims 6 to 13.

15. The intermediate layer is provided between the outer tube and the deformable body. The overtube according to any one of claims 6 to 13.

16. The shape-variable body has a helical tube formed by helically winding a belt-shaped member around the outer circumferential surface of the inner tube. The overtube according to any one of claims 1 to 13.

17. The length of the second region in the longitudinal direction is 5 cm or more and 20 cm or less, The base end of the second region is located within 20 cm from the tip. The overtube according to any one of claims 1 to 13.

18. The length of the first region in the longitudinal direction is longer than that of the second region. The overtube according to any one of claims 1 to 13.

19. The length of the first region in the longitudinal direction is 20 cm or more. The overtube of claim 18.

20. The length of the second region in the longitudinal direction is 5 cm or more and 50 cm or less, The base end of the second region is located within 50 cm from the tip. The overtube according to any one of claims 3 and 9 to 11.

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