JPH1147155A - High frequency incision device for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency incision device for an endoscope, excellent in the properties of washing, disinfecting and sterilizing a wire passage duct. SOLUTION: A high frequency incision device 1 for an endoscope includes a sheath 5 inserted through the endoscope into the body; a lumen 7a formed within the sheath 5 along its longitudinal direction; a pair of openings 9a, 9b formed through the outer peripheral surface of the end of the sheath 5 so as to lead to the lumen 7a; a conductive wire 6 inserted into the lumen 7a and partly brought out of the sheath 5 through the pair of openings 9a, 9b to form an incising part 10, with a high frequency current passed through the conductive wire 6; and a fluid introduction means for introducing a fluid into the lumen 7a. The end of the lumen 7a is closed, and at least one of the pair of openings 9a, 9b is formed to have a greater open area than the area of the lumen 7a when the sheath 5 is cut on a plane perpendicular to its longitudinal axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency incision device for an endoscope which is inserted endoscopically into a body cavity and incises a living tissue, in particular, a duodenal papilla or the like with a high-frequency current.

[0002]

2. Description of the Related Art An incision apparatus which is inserted endoscopically into a body cavity and incises a living tissue in the body cavity with a high-frequency current is disclosed, for example, in Japanese Patent Application Laid-Open No. Hei 5-115492. The incision device disclosed in the above publication has an electrically insulating sheath inserted into a body cavity. This sheath is
It is formed as a multi-lumen tube (porous tube) having a plurality of holes extending along its longitudinal direction. One of a plurality of lumens provided in the sheath;
One is formed as a wire insertion conduit for inserting a conductive wire through which a high-frequency current flows. A pair of openings are formed in the distal end side surface of the sheath and communicate with the wire passage and are located at a predetermined distance from each other in the longitudinal direction of the sheath. Of these openings, the opening on the distal side is formed as a wire introduction port, and the opening on the proximal side is formed as a wire outlet.

The distal end of the conductive wire inserted into the wire insertion conduit is led out of the sheath from the wire outlet formed at the distal end of the sheath, and is then returned to the sheath through the wire inlet. Inside (into the wire passage) and is fixed to the distal end side of the wire passage. Then, in this case, the portion of the conductive wire exposed to the outside between the wire outlet and the wire inlet constitutes an incision for incising the living tissue by coming into contact with the living tissue.

[0004]

In the incision device disclosed in the above publication, the distal end of the wire passage is closed by a closing member or the like in order to prevent body fluids or various germs from entering the wire passage. ing. However, since the wire passage is in communication with the outside through the wire outlet and the wire inlet, it is impossible to prevent body fluids and the like from entering the wire passage through these wire outlets.

[0005] In addition, in the incision device disclosed in the above-mentioned publication, since a cleaning solution or the like cannot be injected into the wire insertion conduit,
Since there is no means (for example, a mouthpiece) for sending a washing solution or the like into the wire insertion pipe, it is not possible to wash out bodily fluids and various bacteria that have entered the wire insertion pipe,
Therefore, there is a problem that filth remains in the wire passage.

In addition, in the cutting device disclosed in the above publication, the wire passage is not communicated with the outside at the tip. That is, the distal end of the wire insertion conduit is closed by the closing member, and the wire inlet on the distal end side for communicating the wire insertion conduit with the outside is not located at the distal end of the wire insertion conduit. Therefore, even if a cleaning solution or the like is sent from the base end side toward the closed distal end side into the wire insertion conduit, the cleaning liquid accumulates at a portion of the wire insertion conduit closer to the distal end than the wire introduction port. It is difficult to reliably flush the waste material to the outside of the wire passage through a pair of wire outlets. This can easily be imagined, even when considering that the wire outlet formed only for the purpose of inserting and extracting the wire has a small diameter.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high-frequency incision device for an endoscope which is excellent in cleaning, disinfecting, and sterilizing properties of a wire insertion pipe. To provide.

[0008]

In order to solve the above-mentioned problems, a high-frequency incision apparatus for an endoscope according to the present invention comprises: an electrically insulating sheath inserted endoscopically into a body; And a pair of openings formed on the outer peripheral surface of the distal end portion of the sheath so as to communicate with the lumen and spaced apart from each other by a predetermined distance along the longitudinal direction of the sheath. And a conductive wire through which a high-frequency current is passed, and a fluid is introduced into the lumen while a part thereof is led out of the sheath through the pair of openings to form an incision. Fluid introduction means, wherein the distal end of the lumen is closed, and at least one of the pair of openings is larger than the area of the lumen when the sheath is cut along a plane perpendicular to the longitudinal axis. Characterized in that it is formed with the opening area are.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a first embodiment of the present invention. As shown in FIG. 1, a high-frequency incision device 1 for an endoscope according to the present embodiment includes an endoscope 2
(See FIG. 3) Insertion section 3 inserted into the patient's body through a treatment tool insertion channel (not shown), and insertion section 3
And an operation unit 4 which is arranged on the base end side and operated by an operator outside the patient's body. A plurality of markings 12 are provided on the outer peripheral surface of the insertion section 3.

As shown in FIG. 2A, the insertion section 3 is formed of a flexible sheath 5 having electrical insulation. The sheath 5 is formed as a multi-lumen tube (porous tube) having four holes (lumens) extending along the longitudinal direction. That is, FIG.
As shown in (b), the sheath 5 has a wire lumen 7a set to an inner diameter through which the conductive wire 6 is inserted and into which the cleaning liquid or the like can be introduced in a state where the conductive wire 6 is inserted.
A multipurpose lumen 7b used for multipurpose such as insertion of a treatment tool such as a guide wire 8 (see FIG. 3); and two lightening lumens 7 for making the sheath 5 flexible.
c, 7c. As will be described later, the multipurpose lumen 7b is also used as an injection conduit for injecting a liquid such as a contrast medium or a washing liquid into the body or a suction conduit for aspirating bodily fluid such as bile. It is set to a sufficient size (inner diameter) that does not hinder the treatment.

A pair of openings 9a and 9b are formed in the distal end side surface of the sheath 5 so as to communicate with the wire lumen 7a and to be spaced apart from each other by a predetermined distance in the longitudinal direction of the sheath 5. Of these openings 9a and 9b, the opening 9a on the distal end side is formed as a wire inlet having an inner diameter substantially equal to the outer diameter of the conductive wire 6, and the opening 9b on the proximal end side is formed as an inner hole area of the wire lumen 7a ( A notch having an opening area larger than the area of the wire lumen 7a (the area of the wire lumen 7a shown in FIG. 2B) when the sheath 5 is cut along a plane orthogonal to the longitudinal axis thereof. It is formed as a wire outlet.

The distal end side of the conductive wire 6 inserted into the wire lumen 7a is led out of the sheath 5 from the wire outlet 9b, and then again into the sheath 5 (in the wire lumen 7a) through the wire inlet 9a. And is fixed to the distal end side of the wire lumen 7a. Then, in this case, the portion of the conductive wire 6 exposed to the outside between the wire outlet 9b and the wire inlet 9a constitutes an incision 10 for incising the living tissue by coming into contact with the living tissue.

The conductive wire 6 is made of a flexible metal wire, the tip of which is a metal pipe 11.
It is inserted and fixed inside. The distal end of the conductive wire 6 is fixed to the sheath 5 by fixing the distal end of the pipe 11 in the wire lumen 7a on the distal end side from the wire introduction port 9a.

The distal end of the sheath 5 is tapered. That is, the outermost dimension D2 of the outermost end of the sheath 5
Is set smaller than the outer diameter dimension D1 of the central portion of the sheath 5. The distal end of the tapered sheath 5 is filled with a sealing agent 12 such as silicon so that the wire lumen 7a and the two hollow portions close the distal end openings of the lumens 7c, 7c. However, the tip of the multipurpose lumen 7b is open without being filled with the sealant 12. Further, the sealing agent 13 is similarly filled in a portion of the wire lumen 7a located between the wire inlet 9a and the wire outlet 9b. That is, the distal end of the wire lumen 7a communicates with the outside only through the wire outlet 9b.

As shown in FIG. 1, the operating unit 4 of the incision device 1
Has a substantially Y-shaped branch portion 14 connected to the proximal end of the sheath 5 constituting the insertion portion 3. From the base end of the branch portion 14, a pair of branch connection portions 14a and 14b extend at a predetermined angle to each other. A wing 24 is provided between the first branch connecting portion 14a and the second branch connecting portion 14b, near the branch portion 14. The wing 24 connects the branch connection portions 14a and 14b to each other,
The base end of the branch portion 14 is reinforced.

The first branch connection part 14a is provided with two bases 15a and 15b communicating with the multipurpose lumen 7b. In this case, the first base 15a is
And the second base 15b.
Can be detachably connected to the watertight adapter 16. Note that the watertight adapter 16 includes a distal end base 22 and a base end base 2.
3 and a tubular sealing material (not shown) inserted between the distal end base 22 and the proximal end base 23. The sealing material is tightened by tightening the base end cap 23 so that the tip end base 2
2 and the base end cap 23, the inner diameter thereof is contracted.

The second branch connection part 14b is provided with a base 17 communicating with the wire lumen 7a. Also,
An operation section main body 18 is connected and fixed to the base end of the second branch connection section 14b. A slider 19 is mounted on the operation section main body 18 so as to be movable in the longitudinal direction. The slider 19 is provided with a conductive plug 20 that is electrically connected to a high-frequency power supply. The base end of the conductive wire 6 is connected and fixed to the conductive plug 20.

Next, an EST for incising the duodenal papillary sphincter using the high frequency incision apparatus 1 for an endoscope having the above configuration will be described. First, the slider 19 of the operation unit 4 is positioned on the distal end side of the operation unit main body 18, and the distal end of the sheath 5 is held in a substantially linear shape. Then, with the distal end portion of the sheath 5 held in a substantially linear shape, the insertion portion 3 is inserted into a treatment tool insertion channel (not shown) of the endoscope 2 previously inserted into the duodenum 41 as shown in FIG. Insert Next, the distal end of the insertion section 3 is projected outward from the distal end opening of the treatment instrument insertion channel of the endoscope 2, and the bile duct 4 is inserted through the papilla 42.
Insert into 3. This insertion operation is performed, for example, by bending the endoscope 2, by raising the insertion section 3 by a treatment tool raising table provided at the distal end of the treatment tool insertion channel of the endoscope, or by inserting the insertion section. 3 can be easily performed by pushing and pulling the whole. afterwards,
If necessary, a syringe (not shown) is attached to the second base 15b with the cap 21 attached to the first base 15a on the first branch connecting portion 14a side of the branch portion 14, and the contrast agent is passed through the multipurpose lumen 7b. Is injected into the bile duct 43, and bile is sucked.

Next, the nipple 42 of the sheath 5 will be described with reference to the marking 12 provided on the outer peripheral surface of the distal end of the sheath 5.
Adjust the insertion depth into the device. Thereafter, the slider 19 of the operation unit 4 is moved to the base end side of the operation unit main body 18. With the operation of the slider 19, the conductive wire 6 is pulled toward the hand side, and the distal end of the sheath 5 is bent in a substantially arc shape. As a result, the incision 10 exposed to the outside of the sheath 5 through the wire inlet 9a and the wire outlet 9b is stretched in an arc shape. In this state, the incision 10 is brought into contact with the papillary sphincter, and a high-frequency current is applied to the conductive wire 6 (incision 10) through the conductive plug 20 of the slider 19,
An incision is made in the papillary sphincter. When incision is completed, slide 1
9 is returned to the position on the distal end side of the operation section main body 18, and the insertion section 3 is pulled out from the treatment instrument insertion channel of the endoscope 2.

In such a procedure, if necessary, the insertion portion 3 is connected to the bile duct 4 by using the guide wire 8 as a guide.
3 can be inserted. That is, the guide wire 8 is inserted into the bile duct 43 in advance through the treatment instrument insertion channel of the endoscope 2, and in this state, the base end of the guide wire 8 is inserted through the distal end opening of the multi-purpose lumen 7 b of the sheath 5. And the insertion portion 3 is inserted into the treatment instrument insertion channel of the endoscope 2 along the guide wire 8. Thereby, the insertion section 3 is inserted from the nipple 42 into the bile duct 43 by the guide of the guide wire 8.

When the guide wire 8 is inserted into the bile duct 43 in a state where the insertion portion 3 has been inserted into the bile duct 43 in advance, the guide wire 8 is connected to the first branch connection portion 14a of the operation portion 4 by the first branch connection portion 14a. What is necessary is just to insert in the multipurpose lumen 7b from the 2nd base 15b. Thereby, the guide wire 8 is inserted into the bile duct 43 through the multipurpose lumen 7b.

In the state where the guide wire 8 is used,
When injecting a liquid such as a contrast agent into the bile duct 43, first,
As shown in FIG. 4, a watertight adapter 16 is connected to the second base 15b of the first branch connection portion 14a, and the guidewire 8 is inserted into the second base 15b and the multipurpose lumen 7b via the watertight adapter 16. insert. Subsequently, the base cap 23 of the watertight adapter 16 is tightened, and a sealing material (not shown) inserted between the front cap 22 and the base cap 23 is pressed between the caps 22 and 23. As a result, the inner diameter of the tubular sealing material shrinks, and the guide wire 8 inserted into the inner hole of the sealing material is sandwiched by the sealing material in a sealed state.
In this state, a syringe (not shown) is attached to the first base 15a, and the contrast agent is injected into the bile duct 43 via the multipurpose lumen 7b.

By the way, during such treatment,
Dirt such as a patient's body fluid adheres to the entire outer surface of the insertion section 3 and also penetrates into the wire lumen 7a through the wire outlet 9b. Of course, the dirt also enters the multipurpose lumen 7b from the opening at the distal end of the sheath 5. However, since the leading ends of the two lightening lumens 7c, 7c are closed by filling with the sealing agent 12, no dirt enters the lightening lumens 7c, 7c. Further, since the distal end of the wire lumen 7a is closed by filling with the sealant 12, no dirt enters the wire lumen 7a from the distal end of the wire lumen 7a.
Further, the inner diameter of the wire inlet 9a is set substantially equal to the outer diameter of the wire 6, and the wire inlet 9a and the wire outlet 9
Since the sealing agent 13 is filled in the portion of the wire lumen 7a between the wire lumen 7b and the wire b, there is no infiltration of dirt into the wire lumen 7a from the wire introduction port 9a.

In order to clean the dirt entering the multipurpose lumen 7b, the cleaning liquid is multipurposely discharged from the second base 15b with the cap 21 attached to the first base 15a of the first branch connection portion 14a. What is necessary is just to inject | pour into the lumen 7b. As a result, the contaminants that have entered the multipurpose lumen 7b are washed out of the multipurpose lumen 7b to the outside from the opening at the tip of the multipurpose lumen 7b.

Further, in order to clean the dirt entering the wire lumen 7a, a cleaning liquid may be injected from the base 17 of the second branch connecting portion 14b. As a result, the dirt entering the wire lumen 7a is washed out to the outside by the washing liquid from the wire outlet 9b having a large opening area.

When disinfecting the multi-purpose lumen 7b and the wire lumen 7a, a disinfectant solution is similarly injected into each of the lumens 7a, 7b from each of the bases 15b, 17. Further, if necessary, sterilization can be carried out by ethylene oxide gas sterilization, autoclave sterilization, or the like.

As described above, in the high-frequency incision apparatus 1 for an endoscope according to the present embodiment, the distal end of the wire lumen 7a and the distal ends of the two lightening lumens 7c, 7c are closed by the filling of the sealant 12. . Therefore, no dirt enters the lumens 7a, 7c from the distal ends, and it is possible to prevent the lumens 7a, 7c from being contaminated by dirt. Further, the sealant 1 is also provided at a portion of the wire lumen 7a between the wire inlet 9a and the wire outlet 9b.
Since 3 is filled, it is possible to prevent infiltration of dirt into this portion.

In the high-frequency incision apparatus 1 for an endoscope according to the present embodiment, dirt may infiltrate into the wire lumen 7a through the wire outlet 9b. Since the liquid can be sent into the wire lumen 7a, the bodily fluid and various germs that have entered the wire lumen 7a can be washed away. Further, even when dirt enters the multipurpose lumen 7b from the opening at the distal end of the sheath 5, a liquid such as a washing liquid can be sent into the multipurpose lumen 7b through the mouthpieces 15a and 15b to wash out body fluids and various bacteria.

Particularly, in the present embodiment, the wire outlet 9b
Is the inner hole area of the wire lumen 7a (the wire lumen 7a when the sheath 5 is cut along a plane orthogonal to its longitudinal axis).
2 (the area of the wire lumen 7a shown in FIG. 2B) is formed in a notch shape having an opening area larger than that of the wire lumen 7a. It is possible to easily discharge the cleaning liquid together with the cleaning liquid from the wire outlet 9b without leaving any infiltration in the lumen 7a and to completely wash it out.

Further, in the high-frequency incision apparatus 1 for an endoscope of the present embodiment, all the portions of the wire lumen 7a on the distal end side from the wire outlet 9b are filled with the sealants 12, 13.
As a result, the distal end of the wire lumen 7a communicates with the outside. That is, the wire lumen 7a
Is closed, and as a result, the wire outlet 9b for connecting the wire lumen 7a to the outside is
a is located at the front end side of FIG. Therefore, it is possible to easily discharge the cleaning liquid together with the cleaning liquid from the wire outlet 9b without leaving any infiltration in the wire lumen 7a and to completely wash the cleaning liquid, thereby enabling efficient and effective cleaning.
Also, at the time of disinfection, the disinfecting liquid is supplied to the wire lumen 7a.
Effective disinfection is feasible due to sufficient distribution within. Furthermore, the prevention of contamination in each lumen and the improvement of the cleaning / disinfecting performance can be realized, so that gas or steam can be introduced into the wire lumen 7a or the multipurpose lumen 7b during ethylene oxide gas sterilization or autoclave sterilization performed after cleaning / disinfection. Is sufficient and effective and safer sterilization is possible.

FIG. 5 shows a second embodiment of the present invention. As shown in the figure, in the high-frequency incision device 1 ′ for an endoscope according to the present embodiment, the conductive wire 6 inserted into the wire lumen 7 a is led out to form an incision 10. A notch-shaped opening 25 is formed in the side surface on the distal end side, and is open long along the axial direction of the sheath 5. That is, in the first embodiment, the wire inlet 9
a and the wire outlet 9b are connected. Of course, in this case, the opening 25 is formed by the wire lumen 7.
The opening area larger than the inner hole area of a (the area of the wire lumen 7a when the sheath 5 is cut along a plane orthogonal to the longitudinal axis (the area of the wire lumen 7a shown in FIG. 5B)). It is formed to have. Further, the wire lumen 7 a is closed only by the filling of the sealing agent 12 at a portion on the tip side with respect to the opening 25. The other configuration is the same as that of the first embodiment.

Accordingly, in the high-frequency incision apparatus 1 'for an endoscope according to the present embodiment, dirt may infiltrate into the wire lumen 7a through the opening 25.
As in the first embodiment, by sending a liquid such as a cleaning solution into the wire lumen 7a through the base 17, body fluids and various bacteria that have entered the wire lumen 7a can be washed away. In particular, in the present embodiment, the opening 25 is located substantially at the forefront of the wire lumen 7a, and
Since the opening area of the wire 5 is larger than the wire outlet 9b of the first embodiment, the cleaning liquid injection performance for the wire lumen 7a is higher than that of the first embodiment.
It is possible to more easily discharge the cleaning liquid together with the cleaning liquid from the wire outlet 9b without leaving the infiltration infiltrated in a.

Further, in the high-frequency incision apparatus 1 ′ for an endoscope according to the present embodiment, the distal end of the sheath 5 is very soft due to the opening 25. Therefore, the operation of bending the insertion section 3 as shown in FIG. 3 is facilitated.

According to the technical contents described above, the following various configurations can be obtained. 1. An electrically insulating sheath inserted endoscopically into the body, a lumen formed in the sheath along the longitudinal direction, and an outer peripheral surface of a distal end portion of the sheath so as to communicate with the lumen. And a pair of openings that are located at a predetermined distance from each other along the longitudinal direction of the sheath, and are inserted into the lumen, and a part thereof is led out of the sheath through the pair of openings to form an incision. And a conductive wire to which a high-frequency current is applied, and a fluid introducing means for introducing a fluid into the lumen, wherein the lumen is located between the distal end of the sheath and at least one of the pair of openings. Is closed, and at least one of the pair of openings has an opening area larger than the area of the lumen when the sheath is cut along a plane perpendicular to the longitudinal axis of the sheath. The endoscopic high-frequency incision and wherein the are.

2. A plurality of lumens extending in the axial direction are formed in the sheath body of the electrically insulating sheath, a conductive wire lumen through which the conductive wire is inserted by one lumen, and another one lumen A multipurpose lumen into which a treatment tool such as a guidewire is inserted and / or a fluid is injected and sucked is formed, and a distal end and a proximal end formed on an outer peripheral surface near a distal end of the sheath body.
The endoscope in which the conductive wire is led out from the pair of wire outlets to the outside of the sheath body, and a knife portion for high-frequency incision is formed by an exposed portion of the conductive wire on the outside of the sheath body. In the high-frequency incision device,
A base for the fluid injection is provided at the proximal end of the conductive wire lumen, and a closing member is provided at the distal end of the sheath body in the conductive wire lumen, and at least one of the pair of wire outlets is electrically conductive. A high-frequency incision device for an endoscope, wherein an opening having a larger opening area than a lumen area of the conductive wire lumen is formed.

3. A plurality of lumens extending in the axial direction are formed in the sheath body of the electrically insulating sheath, a conductive wire lumen through which the conductive wire is inserted by one lumen, and another one lumen A multipurpose lumen into which a treatment tool such as a guidewire is inserted and / or a fluid is injected and sucked is formed, and a distal end and a proximal end formed on an outer peripheral surface near a distal end of the sheath body.
The endoscope in which the conductive wire is led out from the pair of wire outlets to the outside of the sheath body, and a knife portion for high-frequency incision is formed by an exposed portion of the conductive wire on the outside of the sheath body. In the high-frequency incision device,
A base for a fluid injection is provided at the base end of the conductive wire lumen, and a closing member is provided between the distal end portion of the sheath body and the pair of wire outlets in the conductive wire lumen. High-frequency incision device for endoscopes.

[0037]

As described above, the high-frequency incision device for an endoscope according to the present invention can introduce a fluid such as a washing solution into the lumen through which the conductive wire is inserted by the fluid introducing means. It can easily remove infiltrated body fluids and other contaminants, and is excellent in cleaning, disinfecting, and sterilizing properties of the lumen. In particular, since at least one of the openings for leading the conductive wire to the outside of the sheath is formed with an opening area larger than the area of the lumen when the sheath is cut along a plane perpendicular to the longitudinal axis, the lumen Fluid can be easily discharged from the opening together with the fluid without leaving any dirt entering the lumen, and can be completely washed out.

[Brief description of the drawings]

FIG. 1 is a perspective view of a high-frequency incision device for an endoscope according to a first embodiment of the present invention.

2A is a side sectional view of an insertion portion of the high-frequency incision device for an endoscope in FIG. 1, and FIG. 2B is a sectional view taken along line AA in FIG.

FIG. 3 is a diagram showing a state in which a duodenal papilla is incised using the high-frequency incision device for an endoscope in FIG. 1;

FIG. 4 is a perspective view showing a state in which a guide wire is inserted into the high-frequency incision device for an endoscope of FIG. 1 from an operation unit side thereof.

FIG. 5A is a side sectional view of an insertion portion of a high-frequency incision device for an endoscope according to a second embodiment of the present invention, and FIG.
It is sectional drawing which follows the BB line of FIG.

[Explanation of symbols]

 1, 1 '... high frequency incision device for endoscope 5 ... sheath 6 ... conductive wire 7a ... wire lumen 9a, 9b, 25 ... opening 10 ... incision part

Claims (1)

[Claims] 1. An electrically insulating sheath inserted endoscopically into a body, a lumen formed in the sheath along a longitudinal direction thereof, and a distal end of the sheath so as to communicate with the lumen. A pair of openings formed on the outer peripheral surface of the sheath and spaced apart from each other by a predetermined distance along the longitudinal direction of the sheath, are inserted into the lumen, and a part thereof is led out of the sheath through the pair of openings. A conductive wire through which a high-frequency current is applied, and a fluid introduction unit that introduces a fluid into the lumen, wherein a distal end of the lumen is closed, and at least one of the pair of openings is provided. One side is formed with an opening area larger than the area of the lumen when the sheath is cut in a plane perpendicular to the longitudinal axis thereof, wherein the high-frequency incision for an endoscope is formed. Location.