Endoscopic treatment tool

Abstract

This endoscopic treatment tool comprises: a sheath; a rod disposed on the distal end side of the sheath; an electrode connected to the distal end of the rod; and an insulator provided closer to the distal end side than the electrode. A part of the electrode protrudes further outward in the radial direction of the rod than an outer side surface at the proximal end of the insulator.

Description

Endoscopic treatment tools

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 620,006, filed Jan. 11, 2024, the entire contents of which are incorporated herein by reference.

[0002] Conventionally, in endoscopic treatments such as ESD (endoscopic submucosal dissection), endoscopic treatment tools such as high-frequency knives have been used, as shown in Patent Document 1. The surgeon preferably performs incisions on biological tissues using endoscopic treatment tools such as high-frequency knives.

[0003] International Publication No. 2014 / 061701

[0004] When performing ESD procedures, it is necessary to frequently change treatment tools depending on the purpose of the treatment. Therefore, conventional high-frequency knives such as those described in Patent Document 1 are required to be multifunctional so that they can easily perform marking on tissue in addition to incising the tissue without changing the treatment tool.

[0005] In consideration of the above circumstances, an object of the present disclosure is to provide an endoscopic treatment tool that can suitably mark and incise tissue.

[0006] In order to solve the above problems, the present invention proposes the following means: An endoscopic treatment tool according to a first aspect of the present disclosure includes a sheath, a rod arranged on the distal side of the sheath, an electrode connected to the distal end of the rod, and an insulator provided on the distal side of the electrode, wherein a portion of the electrode protrudes radially outward from the rod beyond the outer surface of the base end of the insulator.

[0007] The endoscopic treatment tool of the present disclosure can suitably mark and incise tissue.

[0008] 17 is an overall view of an endoscopic treatment system according to a first embodiment of the present disclosure. FIG. 18 is an overall view showing a treatment tool of the endoscopic treatment system. FIG. 19 is a perspective view of a distal end portion of the treatment tool. FIG. 20 is a side view of the distal end portion of the treatment tool. FIG. 21 is a side view of the distal end portion of the treatment tool. FIG. 22 is a perspective view of the distal end portion of the treatment tool as seen from the base end side. FIG. 23 is a front view of the distal end portion of the treatment tool. FIG. 24 is a view showing a marking step. FIG. 25 is a view showing an incision and dissection step. FIG. 26 is a view showing a modified example of an insulating tip and a modified example of an electrode of the treatment tool. FIG. 27 is a front view of the modified example of the insulating tip as seen from a direction along the longitudinal axis. FIG. 28 is a view showing another modified example of the insulating tip and another modified example of the electrode. FIG. 29 is a view showing another modified example of the insulating tip. FIG. 29 is a cross-sectional view taken along line X1-X1 shown in FIG. 14. FIG. 29 is a cross-sectional view showing another aspect of the modified example of the insulating tip. FIG. 29 is a view showing another aspect of the modified example of the insulating tip. FIG. 29 is a cross-sectional view taken along line X2-X2 shown in FIG. 2

[0009] First Embodiment An endoscopic treatment system 300 according to a first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 9. Fig. 1 is an overall view of the endoscopic treatment system 300 according to this embodiment.

[0010] 1, the endoscopic treatment system 300 includes an endoscope 200 and a treatment tool 100. The treatment tool 100 is inserted into the endoscope 200 when in use.

[0011] [Endoscope 200] The endoscope 200 is a known flexible endoscope, and includes an insertion section 202 that is inserted into the body from the tip, and an operation section 207 attached to the base end of the insertion section 202.

[0012] The insertion section 202 has an imaging section 203, a bending section 204, and a flexible section 205. The imaging section 203, the bending section 204, and the flexible section 205 are arranged in this order from the tip of the insertion section 202. A channel 206 for inserting the treatment tool 100 is provided inside the insertion section 202. A tip opening 206a of the channel 206 is provided at the tip of the insertion section 202.

[0013] The imaging unit 203 includes an imaging element such as a CCD or a CMOS, and is capable of capturing an image of the site to be treated. The imaging unit 203 can capture an image of the distal end of the treatment tool 100 when the treatment tool 100 protrudes from the distal end opening 206 a of the channel 206.

[0014] The bending portion 204 bends in accordance with the operator's operation of the operating portion 207. The flexible portion 205 is a flexible tubular portion.

[0015] The operation unit 207 is connected to the flexible section 205. The operation unit 207 has a grip 208, an input unit 209, a proximal end opening 206b of the channel 206, and a universal cord 210. The grip 208 is a part that is held by an operator. The input unit 209 accepts an operation input for bending the bending section 204.

[0016] The universal cord 210 includes a video signal line for outputting the image captured by the imaging unit 203a to an external device. The video signal line is connected to a display device such as a liquid crystal display via an image processing device including a processor or the like.

[0017] [Treatment Tool 100] Figure 2 is an overall view showing the treatment tool 100. The treatment tool (endoscopic treatment tool, high-frequency treatment tool) 100 is an ESD knife. The treatment tool 100 includes a sheath 1, a knife 2, an insulating tip 3, a manipulation wire 4 (see Figure 4), and an operation unit 5. In the following description, in the longitudinal axis direction (longitudinal direction, axial direction) A of the treatment tool 100, the side that is inserted into the patient's body will be referred to as the "tip side (distal side) A1," and the side of the operation unit 5 will be referred to as the "base side (proximal side) A2."

[0018] The sheath 1 is a long tubular member extending from a distal end 1a to a proximal end 1b. The sheath 1 can be inserted into a channel 206 of the endoscope 200 and can move forward and backward through the channel 206. As shown in Fig. 1, when the sheath 1 is inserted into the channel 206, the distal end 1a of the sheath 1 can protrude and retract from a distal end opening 206a of the channel 206.

[0019] 3 is a perspective view of the distal end portion of the treatment tool 100. The sheath 1 has an outer tube 10 extending in the longitudinal axis direction A and a distal end member 11 provided at the distal end of the outer tube 10. Note that the sheath 1 may be formed by integrally molding the outer tube 10 and the distal end member 11.

[0020] The tip member 11 is formed in a cylindrical shape. Note that the term "cylindrical" includes not only a strict cylindrical shape but also a shape close to a cylindrical shape. The tip member 11 is preferably made of an insulating material such as resin. A through hole 12 is formed in the tip member 11.

[0021] The through hole 12 is a hole provided in the distal end member 11 and passes through the distal end member 11 in the longitudinal axis direction A. The distal end of the through hole 12 communicates with a first opening 12a formed in a distal end surface 14 of the distal end member 11. The proximal end of the through hole 12 communicates with an internal space 19 of the outer tube 10.

[0022] 4 and 5 are side views of the distal end of the treatment tool 100. The knife (electrode) 2 is a metal member. The knife 2 is formed of a material such as stainless steel. The knife 2 is conductive and is energized with high-frequency current. The knife 2 has a rod 20, an electrode 21, and a connector 22.

[0023] The rod (blade, electrode body) 20 is a round-rod-shaped member made of metal. Note that "round-rod-shaped" includes not only a strict round-rod shape but also a shape close to a round-rod shape. The rod 20 is disposed on the distal side A1 of the sheath 1. The operating wire 4 is attached to the proximal end of the rod 20.

[0024] The rod 20 is inserted through the through-hole 12 of the distal end member 11 of the sheath 1 along the longitudinal axis direction A and can freely protrude and retract from the first opening 12a to the distal end side A1. Note that the rod 20 may be fixed in a state where it cannot advance or retreat while protruding from the first opening 12a to the distal end side A1.

[0025] The central axis O2 of the rod 20 in the longitudinal axis direction A preferably coincides with the central axis O1 of the sheath 1 in the longitudinal axis direction A. Note that "coinciding" includes not only a state in which they coincide exactly but also a state in which they almost coincide.

[0026] 6 is a perspective view of the distal end of the treatment tool 100 as viewed from the proximal side A2. The electrode (flange, expanded diameter portion) 21 is connected to the distal end of the rod 20 and is a plate-shaped conductive member extending from the outer peripheral surface of the distal end of the rod 20. The electrode 21 has a protruding portion 21p extending in a direction intersecting the longitudinal axis of the rod 20. In this embodiment, the protruding portion 21p protrudes outward in the radial direction R of the rod 20 beyond the outer surface at the proximal end of the insulating tip (insulator) 3, which will be described later. A planar proximal end surface (rear surface) 21b is formed on the proximal side A2 of the electrode 21. The proximal end surface 21b is not limited to a planar surface and may, for example, be an uneven surface.

[0027] The connector (connecting member) 22 is a cylindrical member made of metal. Note that the term "cylindrical" includes not only a strictly cylindrical shape but also a shape close to a cylindrical shape. The connector 22 connects the rod 20 and the operating wire 4.

[0028] 4, when the knife 2 is advanced relative to the sheath 1, the tip of the connector 22 comes into contact with the tip member 11. When the tip of the connector 22 comes into contact with the tip member 11, the knife 2 is positioned at a first position P1, which is the position on the tip-most side A1.

[0029] 5, when the knife 2 is retracted relative to the sheath 1, the proximal end surface 21b of the electrode 21 comes into contact with the distal end surface 14 of the distal end member 11. The contact between the proximal end surface 21b of the electrode 21 and the distal end member 11 positions the knife 2 at the second position P2, which is the position closest to the proximal end A2.

[0030] The knife 2 can be moved back and forth between the second position P2 and the first position P1 by advancing and retracting the operating wire 4. The knife 2 may be fixed so as not to be able to move back and forth while protruding from the first opening 12a to the distal end side A1.

[0031] 4, by moving the knife 2 closer to the first position P1, a rear space SR can be secured on the proximal side A2 of the electrode 21. By securing the rear space SR of the electrode 21, the surgeon can preferably perform an incision procedure using the electrode 21.

[0032] A high-frequency current is supplied to the knife 2 from the operating wire 4 connected to the operating unit 5. When a high-frequency current is supplied to the knife 2 from the operating wire 4, the rod 20 and the electrode 21 function as a monopolar electrode that outputs the high-frequency current to the biological tissue.

[0033] The insulating tip (insulator) 3 is made of an insulating material such as ceramic or resin. The insulating tip 3 is provided on the distal side A1 of the electrode 21. In this embodiment, the base end 3p of the insulating tip 3 is fixed to the rod 20 in contact with the electrode 21. At least the protruding portion 21p of the electrode 21 protrudes outward in the radial direction R from the outer surface of the base end 3p of the insulating tip 3 (the base end 33p of a tapered surface 33t described later).

[0034] The central axis O3 of the insulating tip 3 in the longitudinal axis direction A preferably coincides with the central axis O1 of the sheath 1 in the longitudinal axis direction A. Note that "coinciding" includes not only a state in which they coincide exactly but also a state in which they almost coincide.

[0035] The insulating tip 3 has a distal end portion 32 disposed on the distal side A1 and a proximal end portion 33 disposed on the proximal side A2. The distal end portion 32 and the proximal end portion 33 are arranged and connected in the longitudinal axis direction A. The distal end portion 32 and the proximal end portion 33 may be formed integrally, or may be formed by connecting separate members.

[0036] The tip portion 32 is formed in a cylindrical shape and has a chamfered portion 32a on the outer periphery of the tip portion 32. The central axis of the tip portion 32 in the longitudinal axis direction A coincides with the central axis O3.

[0037] The base end 33 is formed in a conical shape. Therefore, the outer diameter of the base end 3p of the insulating tip 3 (base end 33p of the base end 33) is smaller than the outer diameter of the tip of the insulating tip (tip of the tip portion 32). The central axis of the base end 33 in the longitudinal axis direction A coincides with the central axis O3. The base end 33 has a tapered surface (inclined surface, inclined portion) 33t that decreases in diameter toward the electrode 21 (toward the base end side A2). Therefore, at least the protruding portion 21p of the electrode 21 is not covered by the insulating tip 3, and the tapered surface 33t is separated from a portion of the electrode 21 with a gap in the longitudinal axis direction A of the rod 20. The portion of the electrode 21 (protruding portion 21p) protrudes outward in the radial direction R of the rod 20 beyond the outer surface of the base end 3p of the insulating tip 3. In the longitudinal axis direction A of the rod 20, the tapered surface 33t and the protruding portion 21p are spaced apart with a gap, and are arranged so that the tapered surface 33t and the tip surface 21f of the protruding portion 21p face each other.

[0038] In this embodiment, the base end 3p of the tapered surface 33t (base end of the base end portion 33, base end of the insulating tip 3) is in contact with the base of the electrode 21. That is, the radially outer side of the electrode 21 is separated from the insulating tip 3, and the radially inner side of the electrode 21 is in contact with the insulating tip 3. However, the electrode 21 does not necessarily have to be in contact with the insulating tip 3. The base end 3p of the tapered surface 33t (base end 33p of the base end portion 33) and a portion of the base of the electrode 21 may be separated with a small gap therebetween.

[0039] The distance from the electrode 21 increases from the base end 33p of the tapered surface 33t toward the tip. Therefore, a forward space (gap) SF is formed between the tapered surface 33t and the protruding portion 21p. That is, the insulating tip 3 and the electrode 21 are fixed to the rod 20 so that a gap is provided between the tapered surface 33t and the protruding portion 21p in the longitudinal axis direction A of the rod 20, and the tapered surface 33t and the distal end surface 21f of the protruding portion 21p face each other. The rod 20 and the electrode 21 may be molded integrally. By ensuring the space (gap) SF in front of the protruding portion 21p, the surgeon can preferably perform incision procedures, marking, and the like using the electrode 21.

[0040] 7 is a front view of the distal end of the treatment tool 100. The electrode 21 has three protrusions 21p. The three protrusions 21p are arranged at equal intervals along the circumferential direction C relative to the longitudinal axis direction A. When viewed from the front along the longitudinal axis direction A, the electrode 21 is formed in a triangular shape. The electrode 21 may also be formed in a four- or five-pronged shape. That is, the electrode 21 may be formed in a radial shape extending radially outward in the radial direction R from the central axis O2 of the rod 20. The electrode 21 may also be formed in a disc shape or a polygonal shape.

[0041] In a direction perpendicular to the longitudinal axis of the rod 20, the shortest distance D2 in the radial direction R from the central axis O2 of the rod 20 to the base end 3p of the outer surface 31 of the insulating tip 3 (the base end 33p of the tapered surface 33t, the base end 33p of the outer peripheral surface of the base end 33) is smaller than the distance D1 in the radial direction R from the central axis O2 of the rod 20 to the top 21t of the protruding portion 21p of the electrode 21 and is greater than the radius D3 of the rod 20 (D1 > D2 > D3). Furthermore, the shortest distance D4 from the central axis O2 of the rod 20 to the tip 33b of the tapered surface 33t (the tip of the outer peripheral surface of the base end 33) 33b formed on the base end 33 of the insulating tip 3 is greater than the distance D1 from the central axis O2 of the rod 20 to the top 21t of the protruding portion 21p of the electrode 21 (D4 > D1). A tip (top) 21t of the protrusion 21p is disposed outward in the radial direction R from a base end 3p of the outer surface 31 of the insulating tip 3.

[0042] The operation wire 4 is a metal wire that passes through the internal space (duct, lumen) 19 of the outer tube 10. The operation wire 4 is made of a material such as stainless steel. The distal end of the operation wire 4 is connected to the rod 20, and the proximal end of the operation wire 4 is connected to the operation unit 5. The operation wire 4 may be a hollow wire. In this case, by providing an opening at the distal end of the insulating tip 3 and connecting the opening to the internal space of the operation wire 4, a fluid such as physiological saline can be ejected from the distal end of the insulating tip 3.

[0043] As shown in FIGS. 1 and 2, the operation unit 5 includes an operation unit main body 51, a slider 52, and a power supply connector 53.

[0044] The distal end of the operation portion main body 51 is connected to the proximal end 1b of the sheath 1. The operation portion main body 51 has an internal space through which the operation wire 4 can be inserted. The operation wire 4 passes through the internal space 19 of the outer tube 10 and the internal space of the operation portion main body 51 and extends to the slider 52.

[0045] The slider 52 is attached to the operation unit main body 51 so as to be movable along the longitudinal axis direction A. The proximal end of the operation wire 4 is attached to the slider 52. When the surgeon moves the slider 52 forward or backward relative to the operation unit main body 51, the operation wire 4, the knife 2, and the insulating tip 3 move forward or backward.

[0046] The power supply connector 53 is fixed to the slider 52. The power supply connector 53 is connectable to a high-frequency power supply device (not shown) and is connected to the proximal end of the operation wire 4 via a conductive wire. The power supply connector 53 is capable of supplying high-frequency current supplied from the high-frequency power supply device to the rod 20 via the operation wire 4. Note that the power supply connector 53 may be fixed to the operation unit main body 51 instead of the slider 52.

[0047] [Method of Using the Endoscopic Treatment System 300] Next, a procedure using the endoscopic treatment system 300 of this embodiment (method of using the endoscopic treatment system 300) will be described. Specifically, an incision and dissection treatment of a lesion in an endoscopic treatment such as ESD (endoscopic submucosal dissection) will be described.

[0048] As a preparatory step, the surgeon identifies the lesion by a known method. Specifically, the surgeon inserts the insertion section 202 of the endoscope 200 into the digestive tract (e.g., the esophagus, stomach, duodenum, or large intestine) and identifies the lesion while observing an image obtained by the imaging section 203 of the endoscope.

[0049] <Insertion Step> The surgeon inserts the treatment tool 100 into the channel 206, and causes the distal end 1 a of the sheath 1 to protrude from the distal end opening 206 a of the insertion portion 202. The surgeon advances the slider 52 of the operation portion 5 relatively to the operation portion body 51, and causes the knife 2 and the insulating tip 3 to protrude.

[0050] <Marking Step> Figure 8 is a diagram showing the marking step. The surgeon advances the slider 52 of the operating unit 5 relative to the operating unit body 51 to position the knife 2 at the distal end A1. That is, the knife 2 is positioned at the first position P1, which is the position closest to the distal end A1. The surgeon uses the protruding portion 21p of the electrode 21 to apply electricity while in contact with the mucosal surface, thereby cauterizing and coagulating the biological tissue (mucosal surface) around the lesion. As a result, a marking M is applied to the mucosal surface. By applying electricity while the outer surface 31 of the electrode 21 and the insulating tip 3 are in contact with the mucosal surface, it is possible to prevent the electrode 21 from being deeply inserted into the tissue and applying electricity to the biological tissue unintentionally. Because the protruding portion 21p is spaced apart from the insulator 3, the surgeon can conveniently apply the marking M to the biological tissue using the tip of the protruding portion 21p. Note that marking M on the biological tissue is different from incision in that it merely denatures the biological tissue (mucosal surface) by coagulating it.

[0051] <Incision and Dissection Step> Figure 9 is a diagram showing the incision and dissection step. Next, the surgeon performs the incision and dissection procedure. As shown in Figure 9, the surgeon applies current to the electrode 21 and rod 20 while the insulating tip 3 and electrode 21 are inserted under the mucosal layer, thereby creating a pre-cut (an entry point for starting the dissection) P in the mucosal layer and / or submucosal layer. With high-frequency current still flowing, the surgeon moves the electrode 21 from the pre-cut P to incise the mucosa at the lesion. With high-frequency current still flowing, the surgeon lifts the mucosa at the incised lesion to expose the submucosal layer, and then dissects the submucosal layer at the incised lesion.

[0052] The surgeon continues the above-mentioned operations (treatments) as necessary, and finally excises the lesion, completing the ESD procedure.

[0053] According to the treatment tool 100 of this embodiment, marking of biological tissue and incision of biological tissue can be suitably performed.

[0054] Although the first embodiment of the present disclosure has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present disclosure. Furthermore, the components shown in the above-described embodiment and modified examples can be configured by appropriately combining them.

[0055] (Variation 1) FIG. 10 shows an insulating tip 3A, which is a variation of the insulating tip 3, and an electrode 21A, which is a variation of the electrode 21. FIG. 11 is a front view of the insulating tip 3A as viewed along the longitudinal axis direction A. The insulating tip 3 of the first embodiment has a tapered surface 33t formed at the proximal end 33. However, the insulating tip 3 does not necessarily have to have a tapered surface. For example, the insulating tip 3A is formed in a cylindrical shape from the distal end to the proximal end. The proximal end 3p of the insulating tip 3A is fixed to the rod 20 while contacting the electrode 21A. The electrode 21A is a disc-shaped conductive member provided at the distal end of the rod 20. As shown in FIG. 11, the outer periphery (protrusion 21u) of the electrode 21A is positioned radially outward in the radial direction R from the outer surface 31 of the insulating tip 3A along its entire circumference. The electrode 21A may also be formed in a radial shape such as a trifurcated shape, a disc shape, or a polygonal shape. In this case as well, at least a portion of the outer periphery of the electrode 21A (protruding portion 21u) is disposed radially outward of the outer surface 31 of the insulating tip 3A.

[0056] (Variation 2) FIG. 12 shows an insulating tip 3B, which is a variation of the insulating tip 3, and an electrode 21B, which is a variation of the electrode 21. The insulating tip 3B has a distal end portion 32B disposed on the distal side A1 and a proximal end portion 33B disposed on the proximal side A2. The distal end portion 32B and the proximal end portion 33B are aligned and connected in the longitudinal axis direction A. The distal end portion 32B and the proximal end portion 33B may be integrally formed, or may be formed by connecting separate members. The distal end portion 32B and the proximal end portion 33B are formed in a cylindrical shape. The outer diameter of the distal end portion 32B is larger than the outer diameter of the proximal end portion 33B. The proximal end 3p of the proximal end portion 33B of the insulating tip 3B is fixed to the rod 20 in contact with the base of the electrode 21B. The electrode 21B has a protruding portion 21p that protrudes outward in the radial direction R beyond the outer surface 3e of the proximal end 3p of the insulating tip 3B (the proximal end 33p of the proximal end portion 33B). A forward space (gap) SF is formed between the tip portion 32B and the protrusion 21p. When the electrode 21B is, for example, disk-shaped, the outer periphery of the electrode 21B is positioned radially outward in the radial direction R from the outer surface of the base end 33B of the insulating tip 3B over the entire circumference. When the electrode 21B is, for example, trifurcated or quadruped, a portion (including the apex) of the electrode 21B is positioned radially outward in the radial direction R from the outer surface 3e of the base end 33B of the insulating tip 3B over the entire circumference. In the longitudinal axis direction A of the rod 20, the tip portion 32B and the protrusion 21p are spaced apart with a gap therebetween, and are positioned so that the base end surface of the tip portion 32B faces the tip surface of the protrusion 21p.

[0057] (Variation 3) FIG. 13 shows an insulating tip 3C, which is a variation of the insulating tip 3, and an electrode 21C, which is a variation of the electrode 21. The insulating tip 3C is formed in a cylindrical shape. The insulating tip 3C is fixed to the rod 20. The base end 3p of the insulating tip 3C is not in contact with the electrode 21C. That is, the insulating tip 3C is fixed to the rod 20 with the base end 3p of the insulating tip 3C separated from the electrode 21C by a gap. The base end 3p of the insulating tip 3C is separated from the electrode 21C (including the protruding portion 21u), and a front space (gap) SF is formed between the insulating tip 3C and the electrode 21C (including the protruding portion 21u). If the electrode 21C is, for example, disc-shaped, the outer periphery (protruding portion 21u) of the electrode 21C is positioned radially outward of at least the base end 3p of the outer surface 31 of the insulating tip 3C along the entire circumference. In this modification, since the insulating tip 3C is cylindrical, the electrode 21C (protrusion 21u) is positioned radially outward of the tip of the outer surface 31 of the insulating tip 3C around the entire circumference. If the electrode 21C has a radial shape, such as a triangular or quadrangular shape, a portion of the electrode 21C (protrusion 21u) is positioned radially outward of at least the base end 3p of the outer surface 31 of the insulating tip 3C. In this modification, since the insulating tip 3C is cylindrical, a portion of the electrode 21C (protrusion 21u) is positioned radially outward of the tip of the outer surface 31 of the insulating tip 3C in the radial direction R when viewed from the front along the longitudinal axis direction A. The base end 3p of the insulating tip 3C may have a tapered surface. In this case, the tapered surface is spaced apart from the entire electrode 21.

[0058] (Variation 4) FIG. 14 is a diagram showing an insulating tip 3D, which is a variation of the insulating tip 3. FIG. 15 is a cross-sectional view taken along line X1-X1 in FIG. 14. FIG. 16 is a cross-sectional view showing another aspect of the insulating tip 3D. The electrode 21 is formed in a triangular shape. At least the base end of the insulating tip 3D has a triangular cross-sectional shape perpendicular to the central axis of the rod 20. In a direction perpendicular to the longitudinal axis of the rod 20, the protruding portion 21p of the electrode 21 protrudes in the direction in which the shortest distance D2 from the central axis O2 of the rod 20 to the base end 3p of the outer surface of the insulating tip 3D is shortest. In other words, the direction in the radial direction R of the rod 20 in which the distance from the central axis O2 of the rod 20 to the outer surface of the base end 3p of the insulating tip 3D is shortest coincides with the direction in which the electrode 21 extends in the radial direction R in the circumferential direction C of the rod 20. In a direction perpendicular to the longitudinal axis of the rod 20, the shortest distance D2 in the radial direction R from the central axis O2 of the rod 20 to the base end 3p of the outer surface of the insulating tip 3D is smaller than the distance D1 in the radial direction R from the central axis O2 of the rod 20 to the top 21t of the protrusion 21p of the electrode 21 and is larger than the radius D3 of the rod 20 (D1 > D2 > D3). Note that, as shown in Fig. 16, the insulating tip 3D is formed in a triangular shape when viewed from the front in the direction along the longitudinal axis A, and each side may be curved so as to approach the central axis O3.

[0059] FIG. 17 shows an insulating tip 3E, which is a modified example of the insulating tip 3, and an electrode 21E, which is a modified example of the electrode 21. FIG. 18 is a cross-sectional view taken along line X2-X2 in FIG. 17. FIG. 19 is a cross-sectional view showing another embodiment of the insulating tip 3E. The electrode 21E is bifurcated. At least the base end of the insulating tip 3E has an elliptical or oval cross-sectional shape perpendicular to the central axis of the rod 20. In a direction perpendicular to the longitudinal axis of the rod 20, the protruding portion 21p of the electrode 21E protrudes in the direction where the shortest distance D2 from the central axis O2 of the rod 20 to the base end 3p of the outer surface of the insulating tip 3E is shortest. In other words, the direction in the radial direction R of the rod 20 where the distance from the central axis O2 of the rod 20 to the outer surface of the base end 3p of the insulating tip 3E is shortest coincides with the direction in which the electrode 21E extends in the radial direction R in the circumferential direction of the rod 20. In a direction perpendicular to the longitudinal axis of the rod 20, the shortest distance D2 in the radial direction R from the central axis O2 of the rod 20 to the base end 3p of the outer surface of the insulating tip 3E is smaller than the distance D1 in the radial direction R from the central axis O2 of the rod 20 to the top 21t of the protrusion 21p of the electrode 21, and is larger than the radius D3 of the rod 20 (D1 > D2 > D3). Note that, as shown in Fig. 19, the insulating tip 3E is formed in a rectangular shape when viewed from the front in the direction along the longitudinal axis A, and the long side may be curved so as to approach the central axis O3.

[0060] Second Embodiment A treatment tool 100H according to a second embodiment of the present disclosure will be described with reference to Fig. 20. In the following description, configurations common to those already described will be assigned the same reference numerals, and duplicate description will be omitted.

[0061] 20 is a side view of the distal end of a treatment tool 100H. The treatment tool (endoscopic treatment tool, high-frequency treatment tool) 100H is an ESD knife. The treatment tool 100H includes a sheath 1, a knife 2H, an insulating tip 3H, a control wire 4, and a control section 5.

[0062] The knife (electrode) 2H is a metal member. The knife 2H is formed of a material such as stainless steel. The knife 2H is conductive and is energized with high-frequency current. The knife 2H includes a rod 20, an electrode 21H, and a connector 22.

[0063] The electrode (flange, expanded diameter portion) 21H is a conical conductive member provided at the tip of the rod 20. A tapered surface 21a is formed on the tip side A1 of the electrode 21H, the diameter of which decreases toward the insulating tip 3H (toward the tip side A1). A flat base end surface (back surface) 21b is formed on the base side A2 of the electrode 21H. The tip of the tapered surface 21a is located inward in the radial direction R of the rod 20 from the base end of the outer surface 31 of the insulating tip 3H. In the longitudinal axis direction A of the rod 20, the tapered surface 21a and a portion of the base end surface 3s of the insulating tip 3H are spaced apart by a gap, and are disposed so as to face each other. When the tip side A1 of the electrode 21H is conical, the base end of the tapered surface 21a has an outer diameter that is the same as or slightly smaller than the outer diameter of the outer surface 31 of the insulating tip 3H. The electrode 21H is not limited to a conical shape, and may be a radial shape such as a trifurcated or quadrupled shape. In this case, the above-described tapered surface 21a is also formed on the tip side A1 of the electrode 21H.

[0064] The insulating tip 3H is formed in a cylindrical shape, and the base end of the insulating tip 3H is fixed to the rod 20 in contact with the electrode 21H.

[0065] The treatment tool 100H according to this embodiment allows marking and incision of biological tissue to be performed appropriately. A front space (gap) SF is formed between the base end of the insulating tip 3H and the tapered surface 21a of the electrode 21H. By ensuring the front space (gap) SF of the electrode 21H, the surgeon can perform incision treatment and the like using the electrode 21H appropriately.

[0066] Although the second embodiment of the present disclosure has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present disclosure. Furthermore, the components shown in the above-described embodiment and modified examples can be configured by appropriately combining them.

[0067] Third Embodiment A treatment tool 100I according to a third embodiment of the present disclosure will be described with reference to Fig. 21. In the following description, configurations common to those already described will be assigned the same reference numerals, and duplicate description will be omitted.

[0068] 21 is a side view of the distal end of a treatment tool 100I. The treatment tool (endoscopic treatment tool, high-frequency treatment tool) 100I is an ESD knife. The treatment tool 100I includes a sheath 1, a knife 2, an insulating tip 3I, a control wire 4, and a control section 5.

[0069] The insulating tip 3I is formed in a cylindrical shape. Three tapered surfaces 33It are formed on at least a portion of the base end of the insulating tip 3I. The tapered surfaces 33It are inclined surfaces (inclined portions) formed in a planar shape, with their normals pointing toward the base end side A2. The three tapered surfaces 33It are evenly spaced along the circumferential direction C. In the longitudinal axis direction A, at least a portion of the tapered surfaces 33It are positioned opposite the protruding portions 21p. Therefore, the extending direction of the tapered surfaces 33It and the extending direction of the protruding portions 21p in the radial direction R of the rod 20 coincide with each other in the circumferential direction C of the rod 20. The base end of the insulating tip 3I is fixed to the rod 20 in contact with the base of the electrode 21.

[0070] At least the protrusion 21p of the electrode 21 protrudes outward in the radial direction R from the outer surface of the base end 3p of the insulating tip 3I (the base end 33p of the tapered surface 33It). In a direction perpendicular to the longitudinal axis of the rod 20, the electrode 21 protrudes outward in the radial direction R in a direction in which the shortest distance from the central axis O2 of the rod 20 to the outer surface 31 of the insulating tip 3I is shortest. That is, the direction in the radial direction R of the rod 20 in which the distance from the central axis O2 of the rod 20 to the outer surface of the base end 3p of the insulating tip 3I is shortest coincides with the direction in which the electrode 21 extends in the radial direction R in the circumferential direction C of the rod 20. Furthermore, the shortest distance in the radial direction R from the central axis O2 of the rod 20 to the outer surface at the base end 3p of the insulating tip 3I is shorter than the distance in the radial direction R from the central axis O2 of the rod 20 to the apex 21t of the protrusion 21p of the electrode 21 and is greater than the radius of the rod 20.

[0071] The treatment tool 100I according to this embodiment allows marking and incision of biological tissue to be performed effectively. The tapered surface 33It formed on the insulating tip 3I ensures a sufficient forward space SF on the distal end side A1 of the protrusion 21p. By ensuring the forward space SF of the protrusion 21p, the surgeon can perform incision procedures using the electrode 21 effectively.

[0072] Although the third embodiment of the present disclosure has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present disclosure. Furthermore, the components shown in the above-described embodiment and modified examples can be configured by appropriately combining them.

[0073] The present disclosure can be applied to an endoscopic treatment tool.

[0074] 300 Endoscopic treatment system 200 Endoscope 100, 100H, 100I Treatment tool (endoscopic treatment tool, high-frequency treatment tool) 1 Sheath 10 Outer tube 11 Distal end member 12 Through hole 12a First opening 14 Distal end surface 19 Internal space (duct, lumen) 2, 2A, 2B, 2C, 2E, 2H Knife (electrode) 20 Rod (blade, electrode body) 21, 21A, 21B, 21C, 21E, 21H Electrode (flange, enlarged diameter portion) 21a Tapered surface 21b Base end surface (rear surface) of electrode 21p Protrusion 21t Top 22 Connector (connecting member) 3, 3A, 3B, 3C, 3D, 3E, 3H, 3I Insulating tip (insulator) 3p Base end of insulating tip 31 Outer surface 32, 32B Distal end portion of insulating tip 33, 33B Proximal end portion of insulating tip 33t, 33It Tapered surface (inclined surface, inclined portion) 33p Proximal end portion of insulating tip 4 Operating wire 5 Operating portion 51 Operating portion main body 52 Slider 53 Power supply connector A Longitudinal axis direction (longitudinal direction, axial direction) A1 Distal end side (distal side) A2 Proximal end side (proximal side) R Radial direction SF Forward space SR Rear space

Claims

1. A treatment instrument for an endoscope, comprising a sheath, a rod disposed on the distal end side of the sheath, an electrode connected to the distal end of the rod, and an insulator provided on the distal end side of the electrode, wherein a part of the electrode protrudes radially outward of the rod more than the outer surface of the base end of the insulator.

2. The treatment instrument for an endoscope according to claim 1, wherein the insulator is fixed to the rod with the base end of the insulator in contact with the electrode.

3. The treatment instrument for an endoscope according to claim 1, wherein the insulator is fixed to the rod with the base end of the insulator spaced apart from the electrode with a gap therebetween.

4. The electrode has a protruding portion extending in a direction intersecting the longitudinal axis of the rod, the protruding portion protruding more than the outer surface of the base end of the insulator, and the shortest radial distance from the central axis of the rod to the outer surface of the base end of the insulator is smaller than the radial distance from the central axis of the rod to the top of the protruding portion of the electrode and larger than the radius of the rod. The treatment instrument for an endoscope according to claim 1.

5. At least a part of the base end portion of the insulator has a tapered surface that tapers toward the electrode, and in the longitudinal axis direction of the rod, the tapered surface is spaced apart from a part of the electrode with a gap therebetween. The treatment instrument for an endoscope according to claim 1.

6. The outer diameter of the base end of the insulator is smaller than the outer diameter of the distal end of the insulator. The treatment instrument for an endoscope according to claim 1.

7. A part of the electrode protrudes radially outward of the rod more than at least the base end of the outer surface of the insulator. The treatment instrument for an endoscope according to claim 1.

8. The outer peripheral portion of the electrode protrudes radially outward of the rod more than at least the base end of the outer surface of the insulator. The treatment instrument for an endoscope according to claim 1.

9. The direction in which the distance from the central axis of the rod to the outer surface of the insulator is the smallest in the radial direction of the rod and the direction in which the electrode extends in the radial direction coincide in the circumferential direction of the rod. The treatment instrument for an endoscope according to claim 1.

10. The electrode has a plurality of protruding portions, and the plurality of protruding portions extend radially outward from the central axis of the rod. The treatment instrument for an endoscope according to claim 1.

11. The insulator has an inclined portion where a part of the base end portion of the insulator is inclined, and in the radial direction of the rod, the direction in which the inclined portion extends from the central axis of the rod and the direction in which the electrode extends in the radial direction coincide in the circumferential direction of the rod. The endoscopic treatment instrument according to claim 1.

12. An endoscopic treatment instrument comprising a sheath, a rod disposed on the distal end side of the sheath, an electrode connected to the distal end of the rod, and an insulator provided on the distal end side of the electrode, wherein, on the outer side in the radial direction of the rod of the electrode, there is a gap from the base end of the insulator, and on the inner side in the radial direction of the rod of the electrode, it is in contact with the base end of the insulator.

13. The base end of the insulator is fixed to the rod with the insulator in contact with the electrode. The endoscopic treatment instrument according to claim 12.

14. The electrode has a protruding portion extending in a direction intersecting the longitudinal axis of the rod, and the protruding portion protrudes more than the outer surface at the base end of the insulator. The endoscopic treatment instrument according to claim 12.

15. The shortest distance in the radial direction from the central axis of the rod to the outer surface at the base end of the insulator is smaller than the distance in the radial direction from the central axis of the rod to the top of the protruding portion of the electrode and larger than the radius of the rod. The endoscopic treatment instrument according to claim 14.

16. The base end portion of the insulator has a tapered surface that tapers toward the electrode, and in the longitudinal axis direction of the rod, the tapered surface is spaced apart from the protruding portion with a gap. The endoscopic treatment instrument according to claim 14.

17. The outer diameter of the base end of the insulator is smaller than the outer diameter of the distal end of the insulator. The endoscopic treatment instrument according to claim 12.

18. In a direction perpendicular to the longitudinal axis of the rod, the electrode protrudes radially outward of the rod from the direction in which the shortest distance from the central axis of the rod to the outer surface of the insulator is the smallest. The endoscopic treatment instrument according to claim 12.

19. The distal end portion of the electrode has a tapered surface that tapers toward the insulator. The endoscopic treatment instrument according to claim 1.

20. A treatment method using an endoscopic treatment tool including a rod and an electrode extending in the radial direction of the rod, the method comprising: energizing in a state of contacting a mucosal surface with the electrode extending in the radial direction of the rod to coagulate the mucosal surface.

21. The treatment method according to claim 20, wherein the endoscopic treatment tool has an insulator on the tip side of the rod, and the mucosal surface is coagulated by energizing in a state of contacting the side surfaces of the electrode and the insulator with the mucosal surface.

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