Incision tool

Abstract

This incision tool comprises: a tube having a lumen and a hole communicating with the lumen; and a knife wire housed in the lumen. The knife wire has, between the distal end of the tube and the proximal end of the tube, an incision part that is exposed to the outside of the tube via the hole part and incises a living body. The knife wire has a low-rigidity portion having a rigidity lower than the rigidity of the incision part.

Description

incision instrument

[0001] The technology disclosed herein relates to dissection instruments.

[0002] Endoscopic sphincterotomy (EST) is known as a treatment for choledocholithiasis. In EST, a surgeon inserts an incision instrument into the papilla, which corresponds to the exit of the bile duct and the pancreatic duct, and makes an incision in the living body with the incision instrument.

[0003] The incision instrument used in endoscopic papillotomy includes a tube and a knife wire (see, for example, Patent Document 1). The knife wire is housed within the lumen of the tube. A portion of the knife wire (hereinafter referred to as the "incision portion") is exposed to the outside of the tube. The surgeon applies a high-frequency current from a high-frequency power source to the knife wire, thereby incising the living body with the incision portion of the knife wire.

[0004] Patent No. 4896351

[0005] In known incision instruments, when a high-frequency current is applied to a knife wire, localized heat is generated when the incision portion comes into contact with a living body, which can cause stress to concentrate at the incision portion and lead to breakage. If the knife wire breaks at the incision portion, the fractured surface can injure the living body or the endoscope. This problem is not limited to incision instruments used in endoscopic papillotomy to incise the nipple, but is a common problem with all incision instruments that are inserted into various organs within the human body to incise the living body, such as the vascular system, lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs.

[0006] This specification discloses a technique that can solve the above-mentioned problems.

[0007] The technology disclosed in this specification can be realized, for example, in the following forms.

[0008] The incision instrument disclosed in this specification includes a tube having a lumen and a hole communicating with the lumen, and a knife wire accommodated in the lumen. The knife wire has an incision portion that exposes to the outside of the tube through the hole between the tip end and the base end of the tube to incise a living body, and a low-rigidity portion having a lower rigidity than that of the incision portion.

[0009] Explanatory drawing showing the external configuration of the incision instrument of the first embodiment, explanatory drawing showing the cross section of the incision instrument at the position II-II of FIG. 1, explanatory drawing showing the longitudinal section of the tip portion of the incision instrument, explanatory drawing showing the external configuration of the knife wire, explanatory drawing showing an example of the operation method of the incision instrument, explanatory drawing showing an example of the operation method of the incision instrument, explanatory drawing showing the external configuration of the knife wire used in the incision instrument of the second embodiment, explanatory drawing showing the external configuration of the knife wire used in the incision instrument of the third embodiment, explanatory drawing showing the external configuration of the knife wire used in the incision instrument of the fourth embodiment

[0010] (First Embodiment) (Configuration of Incision Instrument) FIG. 1 is an explanatory drawing showing the external configuration of an incision instrument 100 according to the first embodiment. FIG. 2 is an explanatory drawing showing the cross section (XY cross section) of the incision instrument 100 at the position II-II of FIG. 1. FIG. 3 is an explanatory drawing showing the longitudinal section (YZ cross section) of the tip portion of the incision instrument 100. The incision instrument 100 is an instrument for incising a living body. The incision instrument 100 is used, for example, in endoscopic sphincterotomy (EST: Endoscopic Sphincterotomy) for the treatment of choledocholithiasis. The incision instrument 100 is not limited to endoscopic sphincterotomy, and may be inserted into each organ in the human body, such as the vascular system, lymphatic gland system, biliary tract system, urinary tract system, airway system, digestive organ system, secretory gland, and reproductive organ, to incise the living body.

[0011] 1 to 3, the positive Z-axis direction is the tip side (distal side) that is inserted into the body, and the negative Z-axis direction is the base side (proximal side) that is operated by the operator. FIG. 1 shows a state in which each part of the incision instrument 100 is approximately linear and parallel to the Z-axis. At least a part of the incision instrument 100 has flexibility to the extent that it can be bent. This also applies to the subsequent figures. In this specification, with regard to the incision instrument 100 and its constituent parts, the tip side end is referred to as the "tip", the tip and its vicinity are referred to as the "tip portion", the base side end is referred to as the "base end", and the base end and its vicinity are referred to as the "base end portion".

[0012] The incision instrument 100 has a tube 10, a knife wire 20, a connector 30, and a handle portion 40. Fig. 1 shows the central axis Ax of the tube 10. In this embodiment, the central axes of the connector 30 and the handle portion 40 substantially coincide with the central axis Ax of the tube 10. However, the central axes of the connector 30 and the handle portion 40 may differ from the central axis Ax of the tube 10.

[0013] The tube 10 is an elongated member extending along a central axis Ax. The outer shape of the cross section of the tube 10 is, for example, substantially circular. The outer diameter of the tube 10 may be constant over its entire length or may vary along the longitudinal direction.

[0014] As shown in FIG. 2 , the tube 10 is formed with a device lumen 16L, a knife wire lumen 17L, and a fluid supply lumen 18L. The device lumen 16L is a lumen that accommodates a combined device such as a guidewire. The device lumen 16L extends longitudinally from the distal end of the tube 10 to a branched portion 19 provided at the proximal end of the tube 10. The knife wire lumen 17L is a lumen that accommodates a knife wire 20. The knife wire lumen 17L extends longitudinally from the distal end to the proximal end of the tube 10. The fluid supply lumen 18L is a lumen for flowing a liquid such as a contrast agent or physiological saline. The fluid supply lumen 18L extends longitudinally from the distal end to the proximal end of the tube 10. The cross-sectional outline of each lumen is, for example, substantially circular. The knife wire lumen 17L is an example of a lumen.

[0015] The tube 10 is formed, for example, from a resin material or a metal material. Examples of resin materials that can be used to form the tube 10 include polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, and fluororesin. Examples of fluororesin that can be used include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene-ethylene copolymer (ECTFE). Examples of metal materials that can be used to form the tube 10 include stainless steel such as SUS304, Ni-Ti alloys, and cobalt-chromium alloys.

[0016] The knife wire 20 is a long member. FIG. 4 is an explanatory diagram showing the external configuration of the knife wire 20. The knife wire 20 includes a first wire portion 21, a second wire portion 22, a third wire portion 23, a fourth wire portion 24, and a fifth wire portion 25, arranged in this order from the distal end to the proximal end. The first wire portion 21 is a portion including the distal end of the knife wire 20. The length of the first wire portion 21 is, for example, 15 mm or more and 50 mm or less. The length of the second wire portion 22 is, for example, 5 mm or more and 20 mm or less. The length of the third wire portion 23 is, for example, 15 mm or more and 50 mm or less. The length of the fourth wire portion 24 is, for example, 50 mm or more and 100 mm or less. The third wire portion 23 is, for example, located within a range where preshaping is performed at the distal end of the tube 10.

[0017] The first wire portion 21, the third wire portion 23, and the fifth wire portion 25 are cylindrical and have a substantially constant outer diameter. The outer diameter of the first wire portion 21 is, for example, 0.10 mm or more and 0.30 mm or less. The outer diameter of the first wire portion 21 may be, for example, 0.15 mm or more and 0.25 mm or less. The outer diameter of the third wire portion 23 is smaller than the outer diameter of the first wire portion 21. Therefore, the rigidity of the third wire portion 23 is lower than the rigidity of the first wire portion 21. The third wire portion 23 is an example of a low-rigidity portion. The outer diameter of the third wire portion 23 is, for example, 50% or more and 99% or less of the outer diameter of the first wire portion 21. The outer diameter of the fifth wire portion 25 is larger than the outer diameter of the first wire portion 21 and the outer diameter of the third wire portion 23. Therefore, the rigidity of the fifth wire portion 25 is higher than the rigidity of the third wire portion 23. The outer diameter of the fifth wire portion 25 may be approximately the same as the outer diameter of the first wire portion 21 .

[0018] The relationship between the rigidity levels of each part of the knife wire 20 can be confirmed by, for example, the following methods: Calculating the rigidity based on the cross-sectional shape of each part Measuring the tensile strength using a testing machine Measuring the bending strength using a testing machine Performing a torsion test on the knife wire 20 and observing at which part breakage occurs.

[0019] The second wire portion 22 has a tapered shape in which the outer diameter gradually increases from the proximal end side toward the distal end side. The outer diameter of the proximal end of the second wire portion 22 is approximately the same as the outer diameter of the distal end of the third wire portion 23, and the outer diameter of the distal end of the second wire portion 22 is approximately the same as the outer diameter of the proximal end of the first wire portion 21. The second wire portion 22 is an example of a tapered portion. The fourth wire portion 24 has a tapered shape in which the outer diameter gradually increases from the distal end side toward the proximal end side. The outer diameter of the distal end of the fourth wire portion 24 is approximately the same as the outer diameter of the proximal end of the third wire portion 23, and the outer diameter of the proximal end of the fourth wire portion 24 is approximately the same as the outer diameter of the distal end of the fifth wire portion 25. The fourth wire portion 24 is an example of a tapered portion.

[0020] The knife wire 20 is formed of, for example, a metal material, such as a stainless steel alloy such as SUS302, SUS304, or SUS316, a Ni-Ti alloy, a nickel-chromium alloy, a cobalt alloy, gold, platinum, tungsten, or an alloy containing these elements.

[0021] 1 to 3, the knife wire 20 is housed in a knife wire lumen 17L formed in the tube 10. As shown in Fig. 3, a fixing member 80 is filled in the distal end of the knife wire lumen 17L. The distal end of the first wire portion 21 of the knife wire 20 (hereinafter referred to as the "fixed portion 20F") is fixed to the distal end of the tube 10 by being fixed to the fixing member 80. As shown in Fig. 1, the proximal end 29 of the knife wire 20 extends from the proximal end of the knife wire lumen 17L through the inner cavity of the connector 30 to the position of the handle portion 40 and is supported by a wire support portion 45 of the handle portion 40, which will be described later.

[0022] As shown in FIG. 3 , a portion of the knife wire 20 (hereinafter referred to as the “exposed portion 20E”) is exposed to the outside of the tube 10 between the distal end and proximal end of the tube 10. More specifically, the tube 10 is formed with a distal hole 12 and a proximal hole 13 that connect the knife wire lumen 17L to the outside. A portion of the knife wire 20 proximal to the fixing portion 20F is exposed to the outside of the tube 10 through the distal hole 12, and a further proximal portion is housed again within the knife wire lumen 17L through the proximal hole 13. The exposed portion 20E is a portion of the knife wire 20 extending from the position where it passes through the distal hole 12 to the position where it passes through the proximal hole 13. In this embodiment, the exposed portion 20E is composed of a proximal portion of the first wire portion 21, a second wire portion 22, and a distal portion of the third wire portion 23. In this embodiment, the exposed portion 20E is always exposed to the outside of the tube 10.

[0023] As shown in FIG. 3 , a proximal portion of the exposed portion 20E of the knife wire 20 is covered with an insulating tube 50. The insulating tube 50 is made of an insulating material such as PTFE or polyamide resin. In this embodiment, the insulating tube 50 covers the third wire portion 23, the second wire portion 22, and a proximal portion of the first wire portion 21 of the exposed portion 20E. The portion of the exposed portion 20E not covered by the insulating tube 50, i.e., the portion of the first wire portion 21, functions as the incision portion 20S that incises the living body. As described above, the rigidity of the third wire portion 23 is lower than that of the first wire portion 21. Because the incision portion 20S is a portion of the first wire portion 21, the rigidity of the third wire portion 23 is lower than that of the incision portion 20S.

[0024] As shown in FIG. 1 , the connector 30 is a tubular member connected to the base end of the tube 10. The connector 30 has a small diameter portion 31, a tapered portion 32, and a large diameter portion 33. The small diameter portion 31 is a portion having a substantially constant outer diameter. The small diameter portion 31 constitutes the tip end of the connector 30. The large diameter portion 33 is a portion having a substantially constant outer diameter that is larger than the outer diameter of the small diameter portion 31. The large diameter portion 33 constitutes the base end of the connector 30. The tapered portion 32 is provided between the small diameter portion 31 and the large diameter portion 33. The outer diameter of the tapered portion 32 gradually increases from the boundary with the small diameter portion 31 to the boundary with the large diameter portion 33.

[0025] A branched portion 39 extending in a direction intersecting the central axis Ax is formed in the small-diameter portion 31 of the connector 30. The inner cavity of the branched portion 39 is connected to the liquid supply lumen 18L formed in the tube 10. A liquid such as a contrast medium or saline is supplied to the liquid supply lumen 18L via the branched portion 39.

[0026] The handle portion 40 is disposed on the base end side of the connector 30. The handle portion 40 has a shaft portion 41 and a handle main body portion 42. The shaft portion 41 is a substantially cylindrical member. The shaft portion 41 is connected to the base end of the connector 30. The inner cavity of the shaft portion 41 is connected to the inner cavity of the connector 30. A ring-shaped first finger receiving portion 43 is provided at the base end of the shaft portion 41.

[0027] The handle main body 42 is a substantially cylindrical member. The handle main body 42 is attached to the shaft 41 so as to be slidable along the central axis Ax. The handle main body 42 is provided with a wire support portion 45 that protrudes into the lumen of the shaft 41. The proximal end 29 of the knife wire 20 is supported by the wire support portion 45. The wire support portion 45 is formed of a conductive material such as metal. A high-frequency power supply (not shown) is connected to the wire support portion 45. High-frequency current from the high-frequency power supply is applied to the knife wire 20 via the wire support portion 45. A pair of ring-shaped second finger rests 44 are provided on the side of the handle main body 42. The handle main body 42 is an example of a support member.

[0028] The connector 30 and the handle portion 40 are formed, for example, from a resin material, such as polyurethane, polypropylene, hard polyvinyl chloride, polycarbonate resin, or acrylic resin.

[0029] (Method of Operating the Incising Instrument 100) FIGS. 5 and 6 are explanatory diagrams showing an example of a method of operating the incision instrument 100. As shown in FIG. 5 , the operator, for example, inserts the thumb into the first finger receiving portion 43 and the index and middle fingers into the second finger receiving portion 44, and then rotates the handle main body 42 relative to the tube 10 (arrow AR2). This generates a rotational torque at the proximal end 29 of the knife wire 20, which is supported by the wire support portion 45 of the handle main body 42. This rotational torque is transmitted via the knife wire 20 to the distal end of the tube 10, which is fixed to the distal end of the knife wire 20. As a result, the tube 10 rotates around the central axis Ax, changing the orientation of the incision portion 20S of the knife wire 20. In this way, the operator can set the orientation of the incision portion 20S of the knife wire 20 to a desired orientation by operating the handle portion 40. The incision instrument 100 may have a locking mechanism that fixes the rotation angle of the handle body 42 (i.e., the direction of the incision portion 20S of the knife wire 20).

[0030] As shown in FIG. 6 , for example, when the operator inserts the thumb into the first finger rest 43 and the index and middle fingers into the second finger rest 44 and pulls the index and middle fingers toward the proximal end (arrow AR1), the handle main body 42 moves toward the proximal end along the outer circumferential surface of the shaft 41. This pulls the proximal end 29 of the knife wire 20, which is supported by the wire support portion 45 of the handle main body 42, toward the proximal end, applying tension to the knife wire 20. This tension causes the distal end of the tube 10, which is fixed to the distal end of the knife wire 20, to bend in an arched shape. From this state, when the handle main body 42 is returned to the distal end, the tension on the knife wire 20 is released, and the distal end of the tube 10 returns to a substantially straight shape. In this way, the operator can manipulate the handle 40 to set the desired degree of curvature of the distal end of the tube 10.

[0031] In endoscopic papillotomy, the surgeon inserts an endoscope into the duodenum and delivers a guidewire inserted through the endoscope to the common bile duct through the opening of the papilla. Next, the surgeon delivers the incision instrument 100 along the guidewire to the opening of the papilla. Specifically, with the guidewire inserted into the device lumen 16L of the incision instrument 100, the surgeon advances the incision instrument 100 distally until the tip of the incision instrument 100 reaches the opening of the papilla. At this time, the surgeon positions the handle body 42 distally ( FIG. 1 ). This straightens the distal end of the tube 10, preventing it from getting caught on the papilla or the common bile duct during delivery.

[0032] Next, the operator rotates the handle body 42 of the handle portion 40 relative to the tube 10 (arrow AR2 in Figure 5), thereby rotating the tip of the tube 10 and setting the orientation of the incision portion 20S of the knife wire 20 to an appropriate orientation for incising the papilla.

[0033] The operator then applies tension to the knife wire 20 by sliding the handle main body 42 toward the base end along the outer circumferential surface of the shaft 41 (arrow AR1 in FIG. 6 ). This bends the distal end of the tube 10 into an arch shape, and the incision portion 20S of the knife wire 20 is pressed against the incision site. In this state, the operator applies a high-frequency current to the knife wire 20 using the high-frequency power supply. This causes the incision portion 20S of the knife wire 20 to incise a predetermined area of ​​the papilla into a predetermined shape.

[0034] Effect of the Present Embodiment As described above, the incision instrument 100 of the present embodiment includes the tube 10 and the knife wire 20. The tube 10 has the knife wire lumen 17L and the distal end hole 12 and the proximal end hole 13 that communicate with the knife wire lumen 17L. The knife wire 20 is housed in the knife wire lumen 17L of the tube 10. Between the distal end and the proximal end of the tube 10, the knife wire 20 has an incision portion 20S that is exposed to the outside of the tube 10 via the distal end hole 12 and the proximal end hole 13 and that incises a living body. The knife wire 20 further includes a third wire portion 23 that has a rigidity lower than that of the incision portion 20S. In the incision instrument 100 of this embodiment, when the knife wire 20 breaks due to application of a high-frequency current to the knife wire 20, the break occurs not in the incision portion 20S but in the third wire portion 23, which has lower rigidity than the incision portion 20S. Therefore, the occurrence of breakage in the incision portion 20S is suppressed. This prevents the fracture surface from damaging the living body or the endoscope when a break occurs in the incision portion 20S.

[0035] In the incision instrument 100 of this embodiment, the outer diameter of the third wire portion 23 is smaller than the maximum outer diameter of the incision portion 20S formed by the first wire portion 21. This allows the rigidity of the third wire portion 23 to be lower than the rigidity of the incision portion 20S without complicating the configuration of the knife wire 20.

[0036] In the incision instrument 100 of this embodiment, the third wire portion 23 is located at a portion of the knife wire 20 that is covered by other members. Specifically, the third wire portion 23 is covered by the insulating tube 50 and the tube 10 and is not exposed to the outside. This effectively prevents the broken surface from damaging the living body or the endoscope, even if the third wire portion 23 breaks.

[0037] In the incision instrument 100 of this embodiment, the third wire portion 23 is located closer to the proximal end than the incision portion 20S. This positions the incision portion 20S closer to the tip of the incision instrument 100, making the procedure using the incision instrument 100 easier.

[0038] In the incision instrument 100 of this embodiment, the knife wire 20 further includes a tapered second wire portion 22 between the third wire portion 23 and the incision portion 20S. The outer diameter of the second wire portion 22 gradually increases with increasing distance from the boundary with the third wire portion 23. This reduces the rigidity gap of the knife wire 20 near the third wire portion 23.

[0039] In the incision instrument 100 of this embodiment, the knife wire 20 further includes a tapered fourth wire portion 24 on the opposite side of the incision portion 20S, across the third wire portion 23. The outer diameter of the fourth wire portion 24 gradually increases with increasing distance from the boundary with the third wire portion 23. This reduces the rigidity gap of the knife wire 20 near the third wire portion 23.

[0040] The incision instrument 100 of this embodiment further includes a handle main body 42 that rotatably supports the proximal end 29 of the knife wire 20. This allows the operator to smoothly change the orientation of the incision portion 20S of the knife wire 20 to a desired orientation by rotating the handle main body 42. Even if the knife wire 20 breaks due to twisting of the knife wire 20, the break will occur in the third wire portion 23, which has lower rigidity than the incision portion 20S, and therefore the break at the incision portion 20S is suppressed.

[0041] In the incision instrument 100 of this embodiment, the minimum outer diameter of the incision portion 20S of the knife wire 20 is 0.10 mm or more and 0.30 mm or less, thereby improving both the rotational torque transmissibility of the knife wire 20 and the incision ability of the knife wire 20.

[0042] 7 is an explanatory diagram showing the external configuration of a knife wire 20a used in an incision instrument of a second embodiment. In the following, among the configuration of the knife wire 20a of the second embodiment, the same configuration as the knife wire 20 of the first embodiment described above will be denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[0043] The knife wire 20a of the second embodiment includes, arranged in this order from the distal end to the proximal end, a first wire portion 21, a third wire portion 23a, a fourth wire portion 24, and a fifth wire portion 25. The knife wire 20a does not include a portion corresponding to the second wire portion 22 of the first embodiment.

[0044] In this embodiment, the fixed portion 20F is a portion on the distal end side of the first wire portion 21. The exposed portion 20E is composed of a portion on the proximal end side of the first wire portion 21 and a portion on the distal end side of the third wire portion 23a. The incision portion 20S is a portion of the first wire portion 21 in the exposed portion 20E that is not covered by the insulating tube 50.

[0045] The outer diameter of the third wire portion 23a is approximately the same as the outer diameter of the first wire portion 21. In the knife wire 20a, the material forming the third wire portion 23a is more flexible than the material forming the first wire portion 21. Therefore, the rigidity of the third wire portion 23a is lower than the rigidity of the first wire portion 21. In other words, the rigidity of the third wire portion 23a is lower than the rigidity of the incision portion 20S. This configuration can be achieved, for example, by forming the third wire portion 23a of the knife wire 20a using a metal material different from the metal material used to form the other portions of the knife wire 20a and joining the third wire portion 23a to the other portions. The third wire portion 23a is an example of a low-rigidity portion.

[0046] In the second embodiment, as in the first embodiment, the knife wire 20a has a third wire portion 23a having a rigidity lower than that of the incision portion 20S, which suppresses breakage in the incision portion 20S and prevents the fracture surface from damaging the living body or the endoscope.

[0047] 8 is an explanatory diagram showing the external configuration of a knife wire 20b used in an incision instrument of a third embodiment. In the following, among the configuration of the knife wire 20b of the third embodiment, the same configuration as the knife wire 20 of the first embodiment described above will be denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[0048] The knife wire 20b of the third embodiment includes, arranged in this order from the distal end to the proximal end, a sixth wire portion 26, a seventh wire portion 27, a third wire portion 23b, an eighth wire portion 28, a first wire portion 21, a fourth wire portion 24, and a fifth wire portion 25. The knife wire 20b does not include a portion corresponding to the second wire portion 22 of the first embodiment.

[0049] In this embodiment, the fixing portion 20F is the sixth wire portion 26. The exposed portion 20E is composed of a portion of the distal end of the first wire portion 21. The incision portion 20S is a portion of the first wire portion 21 in the exposed portion 20E that is not covered by the insulating tube 50. The seventh wire portion 27, the third wire portion 23b, and the eighth wire portion 28 are not included in the exposed portion 20E and are housed in the knife wire lumen 17L.

[0050] The sixth wire portion 26 has a cylindrical shape with a substantially constant outer diameter. The sixth wire portion 26 is a portion including the tip of the knife wire 20b. The seventh wire portion 27 has a tapered shape in which the outer diameter gradually increases from the proximal end toward the distal end. The outer diameter of the proximal end of the seventh wire portion 27 is substantially the same as the outer diameter of the tip of the third wire portion 23b, and the outer diameter of the tip of the seventh wire portion 27 is substantially the same as the outer diameter of the proximal end of the sixth wire portion 26. The seventh wire portion 27 is an example of a tapered portion. The eighth wire portion 28 has a tapered shape in which the outer diameter gradually increases from the distal end toward the proximal end. The outer diameter of the tip of the eighth wire portion 28 is substantially the same as the outer diameter of the proximal end of the third wire portion 23b, and the outer diameter of the proximal end of the eighth wire portion 28 is substantially the same as the outer diameter of the tip of the first wire portion 21. The eighth wire portion 28 is an example of a tapered portion.

[0051] The outer diameter of the third wire portion 23b is smaller than the outer diameter of the first wire portion 21. Therefore, the rigidity of the third wire portion 23b is lower than the rigidity of the first wire portion 21. In other words, the rigidity of the third wire portion 23b is lower than the rigidity of the incision portion 20S. The third wire portion 23b is an example of a low-rigidity portion.

[0052] In this embodiment, the third wire portion 23b is located further distal than the incision portion 20S and further proximal than the fixing portion 20F. The third wire portion 23b is not fixed to the tube 10.

[0053] In the third embodiment, as in the first embodiment, the knife wire 20b has a third wire portion 23b having a rigidity lower than that of the incision portion 20S, which suppresses breakage in the incision portion 20S and prevents the fracture surface from damaging the living body or the endoscope.

[0054] 9 is an explanatory diagram showing the external configuration of a knife wire 20c used in an incision instrument of a fourth embodiment. In the following, among the configuration of the knife wire 20c of the fourth embodiment, the same configuration as the knife wire 20 of the first embodiment described above will be denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[0055] Similar to the first embodiment, the knife wire 20c of the fourth embodiment includes a first wire portion 21c, a second wire portion 22, a third wire portion 23, a fourth wire portion 24, and a fifth wire portion 25, which are arranged in this order from the distal end to the proximal end. In the fourth embodiment, the first wire portion 21c is tapered. More specifically, the outer diameter of the first wire portion 21c gradually decreases from the proximal end to the distal end. Because the incision portion 20S is a part of the first wire portion 21c, the incision portion 20S is also tapered.

[0056] In the fourth embodiment, as in the first embodiment, the knife wire 20c has the third wire portion 23 having a rigidity lower than that of the incision portion 20S, which suppresses the occurrence of breakage in the incision portion 20S and prevents the fracture surface from damaging the living body or the endoscope if breakage occurs in the incision portion 20S.

[0057] In the fourth embodiment, the cutting portion 20S is tapered. This reduces stress concentration on the cutting portion 20S, effectively preventing breakage of the cutting portion 20S. The outer diameter of a portion of the cutting portion 20S is reduced, improving the cutting ability of the cutting portion 20S.

[0058] (Modifications) The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified into various forms without departing from the spirit thereof, for example, the following modifications are also possible.

[0059] In the above embodiment, the method for making the rigidity of the low-rigidity portion of the knife wire 20 (e.g., the third wire portion 23) lower than the rigidity of the cutting portion 20S can be modified in various ways. For example, the low-rigidity portion may be formed using a twisted wire, thereby making the rigidity of the low-rigidity portion lower than the rigidity of the cutting portion 20S. For example, the low-rigidity portion may be made lower in rigidity than the cutting portion 20S by forming a slit or recess in the outer peripheral surface of the low-rigidity portion, scratching the outer peripheral surface of the low-rigidity portion, or subjecting the low-rigidity portion to a treatment that reduces its rigidity (e.g., heat treatment).

[0060] In the above embodiment, the knife wire 20 may be made of a plurality of metal wires. For example, the knife wire 20 may be made of a twisted wire in which a plurality of metal wires are twisted together.

[0061] In the above embodiment, the low-rigidity portion (for example, the third wire portion 23) may have a tapered shape in which the outer diameter gradually increases along the axial direction.

[0062] In the above embodiment, the tube 10 does not necessarily have to be formed with at least one of the device lumen 16L and the liquid supply lumen 18L.

[0063] In the above embodiment, the incision portion 20S of the knife wire 20 does not need to be exposed to the outside at all times, but may be exposed to the outside of the tube 10 at least when the tube 10 is in a predetermined position (for example, when the tube 10 is in a position where it is greatly curved).

[0064] In the above embodiment, the entire exposed portion 20E of the knife wire 20 may function as the cutting portion 20S.

[0065] In the above embodiment, the insulating tube 50 may be omitted. Instead of the insulating tube 50, the outer peripheral surface of the knife wire 20 may be coated with an insulating material. In this case, the portion of the knife wire 20 coated with the insulating material does not fall under the category of a portion covered by another member.

[0066] In the third embodiment, the third wire portion 23 b may be included in the exposed portion 20 E. In this case, the third wire portion 23 b may be covered with an insulating tube, or the outer circumferential surface of the third wire portion 23 b may be coated with an insulating material.

[0067] The technology disclosed in this specification is not limited to the incision instrument 100 that can change the direction of the incision portion 20S by rotating the knife wire 20, but is equally applicable to incision instruments that cannot rotate the knife wire 20.

Claims

1. An incision instrument (100) comprising: a tube (10) having a lumen (17L) and holes (12, 13) communicating with the lumen (17L); and a knife wire (20, 20a, 20b, 20c) housed in the lumen (17L), wherein the knife wire (20, 20a, 20b, 20c) has an incision portion (20S) between the distal end and proximal end of the tube (10) that is exposed to the outside of the tube (10) through the holes (12, 13) and that incises a living body; and low-rigidity portions (23, 23a, 23b) having a rigidity lower than that of the incision portion (20S).

2. An incision instrument (100) according to claim 1, wherein the low-rigidity portion (23, 23a, 23b) is located at a portion of the knife wire (20, 20a, 20b, 20c) that is covered by another member.

3. The incision instrument (100) according to claim 1 or 2, wherein the low-rigidity portion (23, 23a) is located closer to the base end than the incision portion (20S).

4. An incision instrument (100) according to any one of claims 1 to 3, wherein the outer diameter of the low-rigidity portion (23, 23b) is smaller than the maximum outer diameter of the incision portion (20S).

5. An incision instrument (100) according to claim 4, wherein the knife wire (20, 20a, 20b, 20c) further has a tapered portion (22, 28) between the low-rigidity portion (23, 23a, 23b) and the incision portion (20S), and the outer diameter of the tapered portion (22, 28) gradually increases as it moves away from the boundary with the low-rigidity portion (23, 23a, 23b).

6. An incision instrument (100) according to claim 4 or 5, wherein the knife wire (20, 20a, 20b, 20c) further has a tapered portion (24, 27) on the opposite side of the incision portion (20S) across the low-rigidity portion (23, 23a, 23b), and the outer diameter of the tapered portion (24, 27) gradually increases as it moves away from the boundary with the low-rigidity portion (23, 23a, 23b).

7. An incision instrument (100) according to any one of claims 1 to 6, wherein the incision portion (20S) is tapered such that its outer diameter gradually increases along the axial direction.

8. An incision instrument (100) according to any one of claims 1 to 7, further comprising a support member (42) for rotatably supporting the proximal end (29) of the knife wire (20, 20a, 20b, 20c).

9. An incision instrument (100) according to any one of claims 1 to 8, wherein the minimum outer diameter of the incision portion (20S) of the knife wire (20, 20a, 20b, 20c) is 0.10 mm or more and 0.30 mm or less.

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