JP7482592B2 - Endoscopic treatment tools - Google Patents

Description

The present invention relates to an endoscopic treatment tool having a distal treatment section that is inserted and removed from the channel of an endoscope and inserted into a body cavity together with the insertion section of the endoscope to extract biological tissue.

A conventional endoscopic treatment tool used as forceps includes a long sheath, an operating wire, an operating section, a distal treatment section support member provided at the distal end of the sheath, and a cylindrical shaft hole provided at the X-shaped intersection between a pair of arms of the distal treatment section support member, where the support sections of a pair of distal treatment pieces having forceps cup sections at their tips cross each other in an X-shape. A rotating shaft supported at both ends by the pair of arms is inserted into the cylindrical shaft hole so as to be capable of rotating relative to each other, and the distal treatment section is used to squeeze out affected areas of biological tissue with the forceps cup section that opens and closes in conjunction with the advancement and retreat of the operating wire.

JP 2009-297503 A JP 2009-090066 A

With conventional endoscopic treatment tools, even if a pair of tip treatment pieces is precisely formed so that the mating surfaces close completely, when biological tissue is clamped, it is unavoidable that the tips of the mating surfaces will open slightly, making it impossible to extract the affected area, and in the case of hemostatic forceps, there is a problem that the affected area cannot be grasped and slips, making it impossible to pull up the affected area for safety reasons and apply electricity to cauterize it.

The present invention has been made to solve the above problems, and aims to provide an endoscopic treatment tool with excellent operability that is suitable for use as a biopsy forceps or hemostatic forceps, in which the pair of forceps cups are fully closed by moving the operating wire in the distal direction to open the pair of forceps cups and pinch the affected area of the biological tissue, and then the operating wire is pulled by gripping the operating part, and the pair of forceps cups are brought into a state where the base ends of the pair of forceps cups are spaced apart by a small distance while maintaining their tips in close contact with each other, and the interlocking force (holding force) between the tips of the cups increases in proportion to the force with which the operating part is gripped, making it easy to perform resection of the affected area at the tips of the cups, and making it easy to reliably and easily extract the affected area of the biological tissue with the cups.

To achieve the above object, the endoscopic treatment tool according to the first aspect of the present invention comprises a sheath that is inserted into and removed from the channel of an endoscope, a control wire that is arranged to be movable forward and backward within the sheath, a control section that is connected to the rear ends of the sheath and the control wire and controls the control wire to move forward and backward, a distal treatment section support member that has a tube section provided at the distal end of the sheath and a pair of opposing arms that extend distally from the tube section, and a distal treatment section that uses a forceps cup section to extract the diseased part of the biological tissue.

The distal treatment section has a pair of distal treatment pieces including the forceps cup portion, which is the distal end portion, and a support portion that supports each forceps cup portion at the proximal end, the pair of distal treatment pieces cross in an X-shape between the pair of arms of the distal treatment section support member, and a support shaft supported at both ends by the pair of arms is inserted into an axial hole provided at the X-shaped intersection, and the proximal end of the pair of support portions is connected to one end of each of a pair of opening/closing operation links, and the other end is connected to the distal end of the operating wire via an advance/retract transmission link, so that it opens and closes in conjunction with the advance/retraction of the operating wire.

Furthermore, each axial hole provided at each of the X-shaped intersections of the pair of distal treatment pieces is an elliptical axial hole in which the support shaft can move relatively by a minute amount, and when the operation wire is pulled and the pair of forceps cup portions are fully closed, the inclination angle θ of the major diameter line of each elliptical axial hole with respect to the cup portion closing line is 30 to 60 degrees, and an internal gap of each elliptical axial hole with respect to the support shaft is generated toward each of the forceps cup portions with respect to the cup portion closing line and in a direction from the closing surface of the cup portion toward the other forceps cup portion ,
When the operating wire is further pulled and moved slightly from a state in which the pair of forceps cup portions are completely closed, the support shaft moves relatively to the tip end positions of each of the oval axial holes, so that the pair of forceps cup portions are configured to space their base ends apart by a small distance while keeping their tip ends closed.

The endoscopic treatment tool according to a second aspect of the present invention has the same configuration as the first aspect, but in addition thereto, the operating wire and the tip treatment portion are made of a conductive material, and the pair of forceps cup portions are provided with an electrically insulating coating on the surfaces thereof, excluding at least the opposing surfaces which come into close contact with each other when the forceps cup portions are in a fully closed state, and further overlaid with a hydrophilic coating, so that electricity is passed through the operating wire, the forward/backward transmission link, and the opening/closing operation link, enabling hemostasis by electric cauterization to be performed between the opposing surfaces.

The endoscopic treatment tool according to the third aspect of the present invention has the same configuration as the first or second aspect, but has a cutout in the pair of forceps cups so that a side hole is formed when the pair of forceps cups are fully closed, and the opposing surface remains as a convex portion on both sides of the opposing surface.

According to the present invention, when the operating wire is moved toward the tip to open the pair of forceps cups and pinch the affected area of the biological tissue, the operating wire is gripped and the operating wire is pulled, the pair of forceps cups are fully closed, and when the operating wire is further pulled by gripping the operating part tightly, the pair of forceps cups are in a state where the base ends are separated from each other by a small distance while maintaining the tips in close contact with each other, and the interlocking force (holding force) between the tips of the cups becomes stronger in proportion to the force with which the operating part is gripped, so that the affected area can be easily excised at the tips of the cups, and the affected area of the biological tissue can be easily and reliably squeezed with the cups, providing an endoscopic treatment tool with excellent operability that is preferable for use as a biopsy forceps or hemostatic forceps.

1 is a diagram for explaining an endoscopic system including an endoscopic treatment tool according to an embodiment of the present invention. 1 is an overall view of an endoscopic treatment tool according to an embodiment of the present invention. Fig. 3A shows a state in which the forceps cup portions of a pair of distal treatment pieces 15, 16 are open, Fig. 3B shows a state in which the pair of forceps cup portions are completely closed, and Fig. 3C is a longitudinal front view showing the distal end of the endoscopic treatment tool in a state in which the distal ends of the pair of forceps cup portions are closed and the base ends are spaced apart by a small distance. FIG. 4(A) is a front view showing the tip treatment piece 16, FIG. 4(B) is a front view showing the tip treatment piece 15, and FIG. 4(C) is a front view showing a pair of tip treatment pieces 15, 16 when the opposing surfaces of the forceps cup portion are aligned with the cup portion closure line, which relates to the main parts of an endoscopic treatment tool according to an embodiment of the present invention. FIG. 5(A) is a front view showing the opposing surfaces of the forceps cup portion as viewed from the front, and FIG. 5(B) is a right side view showing the detailed shape of the distal treatment pieces used as a pair of distal treatment pieces 15, 16 of an endoscopic treatment tool according to an embodiment of the present invention. FIG. 6(A) is a front view of a tip treatment piece 16, FIG. 6(B) is a front view of a tip treatment piece 15, and FIG. 6(C) is a front view of a pair of tip treatment pieces 15, 16 in which the tips of the opposing surfaces of the forceps cup portion are aligned with the cup portion closure line and the base ends are slightly spaced from the cup portion closure line, relating to the main parts of an endoscopic treatment tool of an embodiment of the present invention. 6(C) from the state shown in FIG. 3(B) and FIG. 4(C) to the state shown in FIG. 3(C) and FIG. 6(C) is an explanatory diagram showing the state in which the pair of forceps cup parts are swung.

Hereinafter, an embodiment of an endoscopic treatment tool according to the present invention will be described with reference to the drawings. In the following description, the side where the distal treatment section is located will be referred to as the distal side, and the side where the operating section is located will be referred to as the proximal side.

[Embodiment]
[Endoscope system]
1 shows an endoscope system 1 to which an endoscopic treatment tool according to embodiment 1 is applied. The endoscope system 1 includes an insertion section 2 for insertion into a body cavity of a living body, an endoscope operation section 3 provided at a base end and having a dial for bending the tip of the insertion section 2 in up, down, left and right directions, and a treatment tool introduction section 4 arranged to connect between the insertion section 2 and the endoscope operation section 3, an endoscope channel 5 formed in the longitudinal direction from the treatment tool introduction section 4 toward the tip of the insertion section 2 is formed, and a pair of distal end treatment pieces 15, 16 and a sheath 11 as a distal end treatment section of an endoscopic treatment tool 10 described later for collecting biological tissue and/or performing hemostasis treatment are inserted into the endoscope channel 5 and configured to be operated by the operation section 13.

[Basic configuration of an endoscopic treatment tool]
2 shows the endoscopic treatment tool 10 according to embodiment 1. In the endoscopic treatment tool 10, the distal end portions 15a, 16a of a pair of distal treatment pieces 15, 16 are forceps cup portions made of conductive metal, and the pair of forceps cup portions (distal end portions) 15a, 16a are opened and closed toward the front, and biological tissue in a body cavity is collected by the pair of forceps cup portions 15a, 16a, or the biological tissue is clamped and a required current is passed through the biological tissue to electrically cauterize the biological tissue and stop bleeding.

The endoscopic treatment tool 10 includes a flexible, elongated sheath 11 that is inserted into and removed from the endoscope channel 5, an operating wire 12 that is arranged within the sheath 11 so that it can be advanced and retreated, an operating section 13 that operates the operating wire 12 to advance and retreat, a distal treatment section support member 14 that is fixedly connected to the distal end of the sheath 11, and a pair of distal treatment pieces 15, 16 that serve as a distal treatment section and are rotatably supported by a support shaft 18 on the distal treatment section support member 14.

The sheath 11 is a thin, tubular body with a length of 500 to 2000 mm that is flexible and has a suitable degree of stiffness (resistance to bending). In this embodiment, the sheath 11 is composed of a coil sheath 11a and a resin outer jacket 11b that covers the outer surface of the coil sheath 11a. The resin outer jacket 11b is made of PTFE, PEEK, PPS, polyethylene, polyimide, or the like, and has flexibility and electrical insulation. It is preferable to use a coil sheath 11a made by tightly winding a metal material, such as a stainless steel wire, having a rectangular cross-sectional shape.

In the endoscopic treatment tool 10, an electrically insulating coating is formed on the inner surface of the coil sheath 11a and the outer surface of the distal treatment section support member 14. In a configuration in which the resin outer jacket 11b is not provided, an electrically insulating coating may be formed on the inner and outer surfaces of the coil sheath 11a.

The operating wire 12 is loosely arranged within the sheath 11 so that it can be advanced and retreated, and is made of a conductive torque wire with high rotational tracking. For example, the entire length of the operating wire 12 may be made of stainless steel, or the operating wire 12 may be made of a stainless steel base end portion and a nitinol (nickel-titanium alloy) tip end portion connected by a stainless steel pipe.

The operating unit 13 has an operating unit body 13a and a slider 13b. The operating unit body 13a has a tip connected to the base end of the coil sheath 11a. The slider 13b is fitted over and slides over the operating unit body 13a within a range corresponding to a slit provided on the side of the operating unit body 13a, and is connected to the base end of the operating wire 12 introduced from the tip surface of the operating unit body 13a into the interior.

The operation unit 13 is configured so that the operation wire 12 can be moved relative to the coil sheath 11a by sliding the operation unit body 13a and the slider 13b relative to each other (advancing and retreating operation), the operation wire 12 can be moved relative to the coil sheath 11a toward the tip side by moving the slider 13b to the left (tip side) in the figure, and the pair of tip treatment pieces 15, 16 can be opened, and the operation wire 12 can be moved relative to the coil sheath 11a toward the base end by moving the slider 13b to the right (base end) in the figure, and the pair of tip treatment pieces 15, 16 can be closed. Thus, the operation unit 13 is configured so that the operation wire 12 can be advanced and retreated relative to the coil sheath 11a, and further so that the pair of tip treatment pieces 15, 16 can be opened and closed through the advancement and retreat of the operation wire 12.

As shown in Figures 3(A)-(C), the distal treatment section support member 14 has a tubular section 14a that is fitted over and connected to the distal end of the coil sheath 11a, and a pair of arms 14b that extend from opposing positions on the distal side of the tubular section 14a. The pair of distal treatment pieces 15, 16 are supported by the distal treatment section support member 14 so as to be openable and closable.

The pair of distal treatment pieces 15, 16 are positioned such that the X-shaped intersection of the support parts 15b, 16b of the pair of distal treatment pieces 15, 16 is between the distal ends of the pair of arms 14b, 14b of the distal treatment part support member 14.

The support shaft 18 is fitted into a pair of bearing holes provided at the distal end of the pair of arms 14b, 14b and fixed at both ends. The support shaft 18 supports the X-shaped intersection located between the pair of arms 14b, 14b of the distal treatment section support member 14.

The support shaft 18 is either forcibly fitted into the bearing holes of the pair of arms 14b, 14b, or fixed by laser welding after fitting, and is loosely fitted into the shaft holes in the middle parts (X-shaped intersections) of the pair of distal treatment pieces 15, 16.

The base ends of the support parts 15b, 16b of the pair of distal treatment pieces 15, 16 are connected to the respective tips of the pair of opening/closing operation links 19, 20 by pin shafts 22, 23. Furthermore, the base ends of the pair of opening/closing operation links 19, 20 are connected to the respective tips of the forward/backward movement transmission link 21 by pin shafts 24, and the forward/backward movement transmission link 21 is connected to the operating wire 12.

In detail, the pin shaft 22 is passed through and fixed to the pin shaft hole 15d provided in the support part 15b of one of the distal treatment pieces 15 and the pin shaft hole provided at the tip of one of the opening and closing operation links 19, thereby connecting one of the distal treatment pieces 15 and one of the opening and closing operation links 19. The pin shaft hole 16d provided in the support part 16b of the other distal treatment piece 16 and the pin shaft hole provided at the tip of the other opening and closing operation link 20 are overlapped, and the pin shaft 23 is passed through and fixed to these pin shaft holes, thereby connecting the other distal treatment piece 16 and the other opening and closing operation link 20. Therefore, the support parts 15b, 16b of the distal treatment pieces 15, 16 and the opening and closing operation links 19, 20 are linked in a diamond shape.

Furthermore, the pin shaft holes provided at the base end of each of the pair of opening/closing operation links 19, 20 are overlapped on both sides of the pin shaft holes provided at the tip end of the forward/reverse transmission link 21, and the pin shaft 24 is passed through and secured to these shaft holes, thereby connecting the pair of opening/closing operation links 19, 20 and the opening/closing operation link 19.

The forward/reverse transmission link 21 has a rod-shaped outer shape and has a wire receiving hole axially inward from the base end face, and the tip of the operating wire 12 is fitted into the wire receiving hole and is fixed by screwing a tightening screw into the outside of the side of the forward/reverse transmission link 21, or by silver brazing, soldering, crimping, etc., thereby connecting the forward/reverse transmission link 21 and the operating wire 12.

Therefore, when the operating wire 12 is moved relative to the sheath 11 in the proximal direction and the crossing angle of the opening and closing operation links 19, 20 becomes smaller, the crossing angle of the support parts 15b, 16b on the proximal side of the pair of distal treatment pieces 15, 16 also becomes smaller, so that the forceps cup parts 15a, 16a on the distal side of the pair of distal treatment pieces 15, 16 close, and when the crossing angle of the opening and closing operation links 19, 20 becomes larger, the crossing angle of the support parts 15b, 16b of the pair of distal treatment pieces 15, 16 also becomes larger, so that the pair of forceps cup parts 15a, 16a open in a fan shape. Thus, when the operating wire 12 is moved relative to the sheath 11, the forceps cup parts 15a, 16a of the pair of distal treatment pieces 15, 16 open and close in a fan shape.

In addition, a hydrophilic coating is formed on the distal treatment section support member 14 and the resin outer sheath 11b of the sheath 11, so that the pair of distal treatment pieces 15, 16 and the sheath 11 can be smoothly introduced into the body cavity without any cramping.

The outer shape of the tip of the coil sheath 11a is ground to provide a small diameter section, and the tube section 14a is inserted into this small diameter section and connected by welding, brazing, or soldering, and the tip of the resin outer jacket 11b is fitted onto the base end of the tube section 14a. However, the base end portion of the tube hole of the tube section 14a of the tip treatment piece support means 14 may be enlarged in diameter, and this enlarged hole section may be fitted onto the tip of the coil sheath 11a and connected by welding, brazing, or soldering.

Therefore, by moving the operating wire 12 back and forth, the forceps cup portions 15a, 16a of the pair of distal treatment pieces 15, 16 can be opened and closed in a fan-like shape toward the front, and the pair of forceps cup portions 15a, 16a are configured to perform procedures in which biological tissue within a body cavity is collected, or the biological tissue is clamped and a required current is passed through it to electrically cauterize the biological tissue and stop bleeding while collecting the biological tissue.

[Characteristic configuration of an endoscopic treatment tool]
Fig. 3(A) shows a state in which the forceps cup portions of the pair of distal treatment pieces 15, 16 are open, Fig. 3(B) shows a state in which the pair of forceps cup portions are completely closed, and Fig. 3(C) shows a state in which the distal ends of the pair of forceps cup portions are closed and the proximal ends are spaced apart from each other by a small distance.

As shown in Figures 3(A)-(C), the pair of distal treatment pieces 15, 16 have forceps cups 15a, 16a, which are distal end portions, support rods 15b, 16b that support the forceps cups 15a, 16a at the proximal end, oval shaft holes 15c, 16c through which the support shaft 18 is inserted at the X-shaped intersection near the forceps cups 15a, 16a, and pin shaft holes (circular shaft holes) 15d, 16d near the proximal end for connecting the opening/closing links 19, 20 with pin shafts 22, 23. The oblong shaft holes 15c, 16c are set so that the inclination angle θ of the major diameter line of each oblong shaft hole 15c, 16c with respect to the cup section closing line Y is 45 degrees. Note that θ = 45 degrees is the optimal angle, and it is desirable that the inclination angle θ is within the range of plus or minus 15 degrees, that is, the inclination angle θ is within the range of 30-60 degrees. The pair of distal treatment pieces 15, 16 is made by preparing two distal treatment pieces as shown in Figures 5 (A) and (B) and combining them facing each other.

4(A)-(C) show the case where the support shaft 18 is in a position where it has moved relatively to the base end position of the oval shaft holes 15c, 16c. The size of the support shaft 18 and the oval shaft holes 15c, 16c is, for example, φ0.6 mm in thickness and 0.31 mm in minor radius of the oval shaft holes 15c, 16c so that the support shaft 18 can rotate and move relatively to the oval shaft holes 15c, 16c. FIG. 4(A) is a front view showing the distal end treatment piece 16 when the opposing surface portion (closing surface) 16e of the forceps cup portion 16a coincides with the cup portion closing line Y, FIG. 4(B) is a front view showing the distal end treatment piece 15 when the opposing surface portion (closing surface) 15e of the forceps cup portion 15a coincides with the cup portion closing line Y, and FIG. 4(C) is a front view showing a pair of distal end treatment pieces 15, 16 when the opposing surface portions (closing surfaces) 15e, 16e of the forceps cup portions 15a, 16a coincide with the cup portion closing line Y. The cup portion closing line Y coincides with a line when the opposing surface portions (closing surfaces) 15e, 16e of the pair of forceps cup portions 15a, 16a are in full contact with each other.

The shaft holes 15c, 16c provided at the X-shaped intersections of the support rods 15b, 16b of the pair of distal treatment pieces 15, 16 are oval shaft holes through which the support shafts can move relatively by minute amounts, and are arranged so that when the operating wire 12 is pulled and the pair of forceps cups 15a, 16a are fully closed, the gap within the hole for the support shaft 18 is formed at an oblique position closer to each of the forceps cups 15a, 16a than the cup section closure joint line Y.

Figure 3 (B) and Figures 4 (A)-(C) show the state in which the operating wire 12 is pulled close to the most retracted position and the pair of forceps cups 15a, 16a are completely closed. In this state, the gap between the oval shaft holes 15c, 16c and the support shaft 18 is created diagonally above the support shaft 18. In other words, the operating wire 12 is pulled and the pair of forceps cups 15a, 16a are completely closed, and in this state, the support shaft 18 is moved relative to the base end positions of each oval shaft hole 15c, 16c, and the hole gap between each oval shaft hole 15c, 16c and the support shaft 18 is created closer to each forceps cup part 15a, 16a with respect to the cup part closing line Y.

Also, Fig. 6 shows the case where the support shaft 18 is in a position where it has moved relatively to the tip end position of the oval shaft holes 15c, 16c. Fig. 6(A) is a front view showing the tip treatment piece 16 in which the tip of the opposing surface portion (closing surface) 16e of the forceps cup portion 16a coincides with the cup portion closing line Y and the tip is slightly spaced from the cup portion closing line Y, Fig. 6(B) is a front view showing the tip treatment piece 15 in which the tip of the opposing surface portion (closing surface) 15e of the forceps cup portion 15a coincides with the cup portion closing line Y and the tip is slightly spaced from the cup portion closing line Y, and Fig. 6(C) is a front view showing a pair of tip treatment pieces 15, 16 in which each tip of the opposing surface portion (closing surface) 15e, 16e of the forceps cup portions 15a, 16a coincides with the cup portion closing line Y and each base end is slightly spaced from the cup portion closing line Y.

Figures 3(C) and 6(C) show the state in which the operating wire 12 is pulled to the most retracted position and the support shaft 18 moves relative to the tip end position of the oval shaft holes 15c, 16c. In this state, the tip side of the pair of forceps cups 15a, 16a remains closed and the base end side is slightly open. In this case, when the oval shaft holes 15c, 16c are engaged with the support shaft 18, a gap δ is created between the oval shaft holes 15c, 16c and the support shaft 18 on both sides of the support shaft 18, diagonally downward.

As shown in Figures 5(A) and (B), the three-dimensional shape of each forceps cup 15a, 16a is roughly bullet-shaped with a concave portion on the half surface of the half body. More specifically, each forceps cup 15a, 16a has a three-dimensional shape with opposing surfaces 15e, 16e that are in close contact with each other on one plane, convex outer surfaces 15f, 16f on the opposite side of each opposing surface 15e, 16e that are formed by combining a semi-cylindrical surface and a quarter hemisphere, and concave portions 15g, 16g that are recessed to form an oval shape on the plane that coincides with the opposing surfaces 15e, 16e.

The opposing surfaces 15e, 16e are overlapping surfaces with a narrow width that surround the recesses 15g, 16g, and have a shape with a large radius of curvature on the tip side or a curved tip portion with a straight line in the middle and arc portions on both sides, straight lines continuing on both sides of the curved tip portion, and a wide area portion where one side of the square rear portion is cut away into an approximately semicircular shape by the recesses 15g, 16g.

Furthermore, as an optional component, each of the forceps cups 15a, 16a has a circular opening 15h, 16h located at the center of the recess 15g, 16g. When the forceps cups 15a, 16a are closed to clamp biological tissue, the circular opening 15h, 16h expels air taken into the inside of the forceps cups 15a, 16a and expels excess biological tissue taken into the cups (recesses 15g, 16g) and liquid generated from the biological tissue, thereby reducing the pressure inside the cups.

Furthermore, as an optional component, each forceps cup portion 15a, 16a has a jagged portion formed by providing notches 15j, 16j in the straight portions on both sides of the opposing surface portion 15e, 16e so as to leave convex portions 15i, 16i. The convex portions 15i, 16i are left as part of the opposing surface portion 15e, 16e. When the pair of forceps cup portions 15a, 16a are closed, the notches 15j, 16j form four heart-shaped horizontal holes with their pointed ends facing the base end side, allowing the biological tissue to protrude from the concave portions 15g, 16g into the heart-shaped horizontal holes, and the convex portions 15i, 16i approach each other facing each other and bite into the biological tissue protruding from the concave portions 15g, 16g into the heart-shaped horizontal holes, and finally abut without any gaps within the holes.

The pair of distal treatment pieces 15, 16 are covered with an insulating film except for the opposing surfaces 15e, 16e and the recesses 15g, 16g. When used as a hemostatic forceps, electricity is supplied via the operating wire 12 to form an electrode surface, and electrical cauterization is performed on biological tissue at the opposing surfaces 15e, 16e and the recesses 15g, 16g.

The endoscopic treatment tool 10 is not characterized by the fact that the forceps cup sections 15a, 16a, which are the distal end portions of the pair of distal treatment pieces 15, 16, are cup-shaped or have jagged sections, but rather by the fact that, as described above, the forceps cup sections 15a, 16a have oval axial holes 15c, 16c whose major diameter line is inclined by θ with respect to the cup section closure line Y, allowing a special opening and closing operation to be performed in which the pair of forceps cup sections 15a, 16a are completely closed when the operating wire 12 is pulled, and furthermore, when the operating wire 12 is pulled strongly, the base ends of the pair of forceps cup sections 15a, 16a are separated from each other by a minute distance.

As shown in FIG. 3(A), when the pair of forceps cups 15a, 16a are open, there are two possible positions of the support shaft 18 relative to the oval shaft holes 15c, 16c. In one state, when the control wire 12 is moved toward the distal end to open the pair of forceps cups 15a, 16a, the support shaft 18 is in a position where it has moved relative to the distal end positions of the oval shaft holes 15c, 16c.

In another state, when the operating wire 12 is pulled in the proximal direction and the pair of forceps cups 15a, 16a begin to close, the support shaft 18 moves relative to the proximal end positions of the oval shaft holes 15c, 16c.

As the operating wire 12 is pulled, the pair of forceps cups 15a, 16a are fully closed as shown in Fig. 3(B) and Fig. 4(A)-(C), and remain in the base end positions of the oval shaft holes 15c, 16c. When the operating wire 12 is further pulled by firmly gripping the operating part 13, the support shaft 18 moves relatively to the tip end positions of the oval shaft holes 15c, 16c as shown in Fig. 3(C) and Fig. 6(A)-(C), and the base ends of the pair of forceps cups 15a, 16a are spaced apart by a small distance while maintaining their tips in close contact with each other. This increases the interlocking force (holding force) between the tips of the cups in approximately proportion to the force with which the operating part 13 is gripped, making it easy to resect the affected area at the tips of the cups, and the affected area of the living tissue can be extracted reliably and easily with the pair of forceps cups 15a, 16a.

Figure 7 shows the pair of forceps cups 15a, 16a swung from the state shown in Figure 3 (B) and Figure 4 (C) to the state shown in Figure 3 (C) and Figure 6 (C). First, in Figure 7, when the pair of forceps cups 15a, 16a are fully closed as shown by the chain lines, the support shaft 18 is located at the base end position of each oval shaft hole 15c, 16c, and when the operating wire 12 is pulled toward the base end by a small required distance, the forward/reverse transmission link 21 shown in Figure 3 (C) also moves together with the forceps cups 15a, 16a. At the same time, the opening/closing operation links 19, 20 move slightly, and the support shaft 18 moves relatively to the tip end position of each oval shaft hole 15c, 16c. As a result, the pair of distal treatment pieces 15, 16 are moved a small distance toward the proximal end while the distal curved portions of the forceps cup portions 15a, 16a remain in close contact, and the support portions 15b, 16b of the pair of distal treatment pieces 15, 16 swing so as to bulge outward as shown by the solid lines in Figure 7.

As shown in Figures 3(B) and 4(C), the oval shaft holes 15c and 16c eliminate the hole gap δ that occurred at the base end of the support shaft 18 and at a diagonal position closer to the forceps cup sections 15a and 16a than the cup section closure line Y, and as shown in Figures 3(C) and 6(C), a hole gap δ occurs at a diagonal position (opposite position) on the base end side of the support shaft 18, and the base ends of the forceps cup sections 15a and 16a are spaced apart by a small distance C (e.g., 0.1-0.3 mm) while the curved tip sections are in close contact with each other.

As a result, the tip sides of the pair of forceps cups 15a, 16a are in close contact with each other and the closing force is concentrated at the tip of the cups, making it easy to resect the affected area and extracting affected areas of biological tissue. This provides excellent operability and makes it suitable for use as a biopsy forceps or hemostatic forceps.

If the curved tip portions of the pair of forceps cup portions 15a, 16a were to be in close contact with each other and the base ends were not to open by a small amount, resulting in a completely closed state, it would be very difficult to process the cup portions using a file or the like, and the tips would not fit together perfectly, resulting in a closed state with a gap, and the presence of a gap on the tip side when the affected area is clamped would result in poor extraction of the affected area. With the above configuration, the curved tip portions of the pair of forceps cup portions 15a, 16a are in close contact with each other and the base ends are able to open by a small amount, which makes it possible to overcome the difficulty of processing the cup portions using a file or the like.

When used as a hemostatic forceps, the curved tip portions of the pair of forceps cup portions 15a, 16a can be secured to clamp biological tissue, so that the affected area can be grasped, and for safety, the affected area can be pulled up and high-frequency current can be passed through the pair of forceps cup portions 15a, 16a to cauterize the grasped portion of the affected area.

In this embodiment (present invention), in order to keep the curved tip portions of the pair of forceps cup portions 15a, 16a in close contact with each other and to keep the base ends of the pair of forceps cup portions 15a, 16a apart by the separation dimension C, the oval axial holes 15c, 16c must be provided with the major diameter line of the oval tilted as shown in the figure, but there are required conditions to set the separation dimension C between the base ends of the pair of forceps cup portions 15a, 16a to the required dimension.

Specifically, the inclination angle θ of the major diameter line of the oval shaft holes 15c, 16c with respect to the cup portion closing line Y, the distance δ (= size of the gap within the hole = deviation dimension) by which the support shaft 18 can slide relative to the oval shaft holes 15c, 16c, and the length L from the center of curvature closer to the forceps cup portion of the two centers of curvature of the oval shaft holes 15c, 16c to the tip of the forceps cup portion 15a, 16a are each set to an appropriate value, and the separation dimension C is determined. Here, θ should be an appropriate value in the range of 30-60 degrees, δ should be 0.1-0.25 mm, and L should be 0.1-0.5 mm.

In Figures 4(A), 4(B) and 6(A), 6(B), the oval shaft hole 16c is a hole that allows the support shaft (circular shaft) 18 of φ0.6 mm to move 0.1 mm at an angle of 45 degrees upward to the right in the figures. The dimensions L and δ in the figures are changed to obtain different values for the separation dimension C in the figures. In Figure 5, the dimensions A and B in the figures are, for example, 2.3 mm and 2.85 mm. The dimension C is a function with variables θ, L, and δ, and increases as θ, L, and δ increase.
In the example of geometric analysis under the above dimensional conditions,
(1) When θ = 45 degrees, L = 3.3 mm, and the deviation dimension δ = 0.2 mm, C = 0.18 mm.
(2) When θ = 45 degrees, L = 4.8 mm, and δ = 0.2 mm, C = 0.22 mm.
(3) When θ = 45 degrees, L = 4.0 mm, and δ = 0.25 mm, C = 0.25 mm.
(4) When θ = 45 degrees, L = 3.85 mm, and δ = 0.1 mm, C = 0.1 mm.
Among the above (1)-(4), (4) had the best gripping function in forceps manipulation.

According to the present invention, the device has a pair of distal treatment pieces including a forceps cup section and a support section for extracting the affected part of the biological tissue, and crosses between the arms of the distal treatment section support member in an X-shape, and the X-shaped crossing section is supported by a support shaft, and opens and closes in conjunction with the advancement and retreat of the operating wire. The oval shaft hole provided at the X-shaped crossing section is configured such that, when the pair of forceps cup sections are fully closed, a gap in the hole with respect to the support shaft is generated on the base end side of the support shaft and in a diagonal position toward the base end of the support shaft. When the pair of forceps cup sections are opened to pinch the affected part of the biological tissue and pull the operating wire in the base end direction while keeping the sheath immobile, the pair of forceps cup sections close. The pair of forceps cup sections are then in a non-contact state on the base end side and in a contact state on the tip end side, and subsequently the contact state on the tip side is maintained and the base end side is in a contact state. This allows the affected part of the biological tissue to be extracted reliably, and a special action that is preferable for use as a biopsy forceps or hemostatic forceps can be obtained, and an endoscopic treatment tool with excellent operability can be provided.

1...endoscope system,
2...insertion part,
3...endoscope operation unit,
4...Treatment tool introduction section,
5...endoscope channel,
10...endoscopic treatment tool,
11...sheath,
11a...coil sheath,
11b...resin outer cover,
12...operation wire,
13...Operation unit,
13a...operation unit main body,
13b...slider,
14... Distal end treatment section support member,
14a...Cylindrical portion,
14b...Arm,
15, 16... Distal treatment piece 15a, 16a... Forceps cup portion 15b, 16b... Support portion,
15c, 16c...elliptical shaft hole,
15d, 16d...pin shaft hole,
15e, 16e... opposing surface portion 15f, 16f... convex outer surface 15g, 16g... recess 15h, 16h... circular opening,
15i, 16i...protruding portion (part of the opposing surface portion)
15j, 16j...notch portion,
18...support shaft,
19, 20...Opening and closing operation links,
21...forward and backward transmission link,
22, 23, 24...pin shaft,
25, 26 ... stopper members,
C: Distance between the base ends of the pair of forceps cup portions,
L: length from the center of curvature near the forceps cup portion to the tip of the forceps cup portion; Y: cup portion closing line; θ: inclination angle of the major diameter line of the oval shaft hole to the cup portion closing line; δ: relative slidable distance of the support shaft to the oval shaft hole.

Claims (3)

A long sheath that is inserted into and removed from a channel of an endoscope;
A manipulation wire disposed within the sheath so as to be capable of advancing and retreating;
an operation unit connected to a rear end side of the sheath and the operation wire and configured to move the operation wire forward and backward;
a distal end treatment section support member having a tubular section provided at a distal end of the sheath and a pair of opposing arm sections extending distally from the tubular section;
a pair of distal treatment pieces including a forceps cup portion as a distal end portion and a support portion for supporting each of the forceps cup portions at a proximal end side, the pair of distal treatment pieces crossing in an X-shape between the pair of arms of the distal treatment unit support member, a support shaft supported at both ends by the pair of arms being inserted into an axial hole provided at the X-shape intersection, and the proximal end of the pair of support portions being connected to one end of each of a pair of opening/closing operation links and the other end being connected to the distal end of the operation wire via an advance/retract transmission link, and a distal treatment unit for treating an affected part of a living tissue with the forceps cup portion which opens and closes in conjunction with the advance/retraction of the operation wire,
Each axial hole provided at each of the X-shaped intersections of the pair of distal treatment pieces is an elliptical axial hole in which the support shaft can move relatively by a minute dimension, and when the operation wire is pulled and the pair of forceps cup portions are fully closed, the inclination angle θ of the major diameter line of each elliptical axial hole with respect to the cup portion closing line is 30 to 60 degrees, and an internal gap of each elliptical axial hole with respect to the support shaft is generated toward each of the forceps cup portions with respect to the cup portion closing line and in a direction from the closing surface of the cup portion toward the other forceps cup portion ,
When the operating wire is further pulled and moved slightly from a state in which the pair of forceps cup portions are completely closed, the support shaft moves relatively to the tip end positions of each of the oval axial holes, thereby causing the pair of forceps cup portions to space their base ends apart by a small distance while keeping their tip ends closed. The operation wire and the distal end treatment portion are made of a conductive material,
The endoscopic treatment tool according to claim 1, characterized in that, when the pair of forceps cup portions are in a completely closed state, an electrically insulating coating is provided on the surfaces excluding at least the opposing surfaces that are in close contact with each other, and a hydrophilic coating is further provided on top of that, and electricity is passed through the operating wire, the forward/backward transmission link, and the opening/closing operation link, so that hemostasis by electric cauterization can be performed between the opposing surfaces. 3. The endoscopic treatment tool according to claim 1, wherein the pair of forceps cup portions are provided with cutouts so as to form side holes when the pair of forceps cup portions are in a fully closed state, and so that the opposing surface portions remain as convex portions on both sides of the opposing surface portions.

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