Bipolar forceps-type treatment instrument

Abstract

In bipolar forceps-type instruments, short circuits between a pair of forceps pieces are reliably avoided. [Solution] The bipolar forceps-type treatment instrument (bipolar hemostatic forceps 1) inserted into the body via an endoscope comprises a sheath portion 10 through which drive wires 13a and 13b are inserted, an operating portion 20 for sliding the drive wires 13a and 13b relative to the sheath portion 10, a support member 32 provided at the distal end of the sheath portion 10, and a pair of forceps pieces 31 rotatably attached to the support member 32, which function as a pair of high-frequency electrodes and have gripping portions 31a that open and close in conjunction with the sliding of the drive wires 13a and 13b relative to the sheath portion 10. When the gripping portions 31a of the pair of forceps pieces 31 are closed to the maximum extent by the operating portion 20, the gripping portions 31a of the pair of forceps pieces 31 face each other so as to be substantially parallel, and a gap is formed between the gripping portions 31a of the pair of forceps pieces 31 without the gripping portions 31a of the pair of forceps pieces 31 contacting each other.

Description

Technical Field

[0001] The present invention relates to a bipolar forceps type treatment instrument that is inserted into the body through an endoscope and performs treatments such as hemostasis using high-frequency current.

Background Art

[0002] Conventionally, a bipolar forceps type treatment instrument that is inserted into the body through the forceps hole of an endoscope to perform hemostasis, tissue incision, etc. is known. For example, a bipolar hemostasis forceps as a bipolar forceps type treatment instrument is provided with a pair of forceps pieces (also called cups) that function as a pair of bipolar electrodes at its tip. By sandwiching the body tissue with the pair of forceps pieces and energizing, the tissue can be cauterized and coagulated to stop bleeding.

[0003] Patent Document 1 below describes a forceps type high-frequency treatment instrument having a pair of forceps pieces that function as high-frequency electrodes. In the forceps type high-frequency treatment instrument described in Patent Document 1, the gripping portion of each forceps piece has a flat plane portion and a tip convex tooth provided at the tip of the plane portion. In a state where the pair of forceps pieces are closed, the plane portion of one forceps piece and the plane portion of the other forceps piece are configured to face each other substantially parallel to each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventional bipolar forceps-type instruments have a problem in that the pair of forceps pieces come into contact with each other, preventing proper tissue ablation. Specifically, when no tissue is grasped, the pair of forceps pieces may come into contact and conduct electricity, or even when tissue is grasped with the pair of forceps pieces, if the tissue is grasped too tightly, electricity may conduct between the pair of forceps pieces. As a result, the high-frequency current shorts through the pair of forceps pieces, preventing the high-frequency current from passing through the tissue and thus preventing proper tissue ablation, as well as causing the instrument itself, including the forceps pieces, to overheat.

[0006] The present invention has been made in view of the above problems, and aims to provide a bipolar forceps-type treatment instrument that reliably avoids short circuits between a pair of forceps pieces. [Means for solving the problem]

[0007] To achieve the above objective, the bipolar forceps-type treatment instrument according to the present invention is a bipolar forceps-type treatment instrument inserted into the body via an endoscope, comprising: a sheath portion through which a drive wire is inserted; an operating portion for sliding the drive wire relative to the sheath portion; a support member provided at the distal end of the sheath portion; and a pair of forceps pieces rotatably attached to the support member, functioning as a pair of bipolar high-frequency electrodes, and having gripping portions that open and close in conjunction with the sliding of the drive wire relative to the sheath portion, wherein when the gripping portions of the pair of forceps pieces are closed to the maximum extent by the operating portion, the gripping portions of the pair of forceps pieces face each other so as to be substantially parallel, and a gap is formed between the gripping portions of the pair of forceps pieces without the gripping portions of the pair of forceps pieces contacting each other.

[0008] With the above configuration, contact between the gripping portions of the pair of forceps can be reliably avoided, preventing short circuits between the pair of forceps. This allows for proper cauterization of tissue while suppressing excessive heat generation, providing a bipolar forceps-type treatment instrument with superior safety and reliability. Furthermore, even when the gripping portions of the pair of forceps are closed to their maximum extent, the tissue can be properly cauterized by pressing the gripping portions of the pair of forceps against the tissue and allowing the tissue to enter the gap between them.

[0009] The bipolar forceps-type treatment instrument according to the present invention is fixed to the support member and includes an insulating spacer that rotatably supports the pair of forceps pieces while electrically insulating them from each other, wherein the insulating spacer has a rotation restricting portion that contacts the pair of forceps pieces when the gripping portions of the pair of forceps pieces are closed by the operating portion, thereby restricting the closing operation of the gripping portions of the pair of forceps pieces, and the pair of forceps pieces may contact the rotation restricting portion when the gripping portions of the pair of forceps pieces are closed to the maximum extent by the operating portion, thereby forming the gap between the gripping portions of the pair of forceps pieces in the fully closed state.

[0010] With the above configuration, the rotation restricting portion provided on the insulating spacer creates an appropriate gap between the gripping portions of the pair of forceps when they are fully closed, thereby reliably preventing contact between the pair of forceps.

[0011] The bipolar forceps-type treatment instrument according to the present invention may have a plurality of protruding teeth on the surfaces of the gripping portions of the pair of forceps pieces that face each other.

[0012] With the above configuration, even when a gap is formed between the gripping portions of a pair of forceps in their most closed state, the multiple protrusions provided on the opposing surfaces of each gripping portion of the pair of forceps suppress slippage of the tissue being gripped, allowing for stable gripping of the tissue.

[0013] In the bipolar forceps-type treatment instrument according to the present invention, the gap between the gripping portions of the pair of forceps pieces, formed when the gripping portions of the pair of forceps pieces are closed to their maximum extent, may be 0.07 to 0.2 mm.

[0014] If the gap between the gripping portions of a pair of forceps is too narrow, there is a possibility of short circuits between the forceps, and if the gap is too wide, it may not be possible to stably grasp the tissue. By setting the gap between the gripping portions of a pair of forceps to 0.07 to 0.2 mm as in the above configuration, it is possible to realize a well-balanced bipolar forceps-type treatment instrument that ensures no short circuits between the pair of forceps while also securing appropriate gripping force. [Brief explanation of the drawing]

[0015] [Figure 1] This is a plan view showing the overall configuration of a bipolar hemostatic forceps in an embodiment of the present invention. [Figure 2] This is a cross-sectional view along line II in Figure 1. [Figure 3] Figure 1 is a perspective view showing the configuration of the distal end of a bipolar hemostatic forceps. [Figure 4] Figure 1 is a plan view showing the configuration of the distal end of the bipolar hemostatic forceps, with the gripping portions of the pair of forceps pieces in the open position. [Figure 5] This figure shows the pair of forceps pieces in the closed position. [Figure 6] Figure 1 is a partial cross-sectional view showing the configuration of the distal end of the bipolar hemostatic forceps, with the gripping portions of the pair of forceps pieces in an open position. [Figure 7] This figure shows the pair of forceps pieces in the closed position. [Figure 8] Figure 1 is a perspective view showing a piece of the bipolar hemostatic forceps. [Figure 9] Figure 8 is a top view showing the forceps section. [Figure 10] Figure 1 is a perspective view showing the insulating spacer of a bipolar hemostatic forceps. [Figure 11] Figure 10 is a plan view showing the insulating spacer. [Figure 12] Figure 7 is a magnified view showing the distal end of the bipolar hemostatic forceps.

Best Mode for Carrying Out the Invention

[0016] While referring to the drawings, the bipolar forceps type treatment instrument in the embodiment of the present invention will be described. In this specification, the proximal side (outside the patient's body) of the user who uses the bipolar forceps type treatment instrument is described as the proximal side, and the inside of the patient's body is described as the distal side. The drawings referred to in this specification do not necessarily have an accurate scale with respect to the actual dimensions, and a part is exaggerated or simplified in order to schematically show the configuration according to the present invention.

[0017] Hereinafter, a bipolar hemostatic forceps, which is one of the bipolar forceps type treatment instruments in the embodiment of the present invention, will be described. However, the present invention is not limited to the bipolar hemostatic forceps, and can also be applied to a bipolar forceps type treatment instrument used for purposes other than hemostasis.

[0018] First, while referring to FIGS. 1 and 2, the configuration of the bipolar hemostatic forceps 1 in the present embodiment will be described. FIG. 1 is a plan view showing the overall configuration of the bipolar hemostatic forceps 1 in the present embodiment. FIG. 2 is a cross-sectional view taken along line I-I of FIG. 1.

[0019] The bipolar hemostatic forceps I in the present embodiment is generally configured to include a sheath portion 10, an operation portion 20, and a treatment portion 30. An operation portion 20 disposed outside the body is provided on the proximal side of the sheath portion 10. A treatment portion 30 inserted into the body is provided on the distal side of the sheath portion 10.

[0020] The operation portion 20 includes a base 21, a slider 22, and a tip cap 23, and the treatment portion 30 includes a forceps portion having a pair of forceps pieces 31 provided so as to be able to open and close with respect to each other. By operating the operation portion 20, the pair of forceps pieces 31 can be opened and closed and rotated around the central axis (sheath axis).

[0021] The operating unit 20 includes a pair of electric wires (cables) 24a and 24b and a plug 24 provided on their proximal ends. These electric wires 24a and 24b are electrically connected to a high-frequency power supply (not shown) via the plug 24 to receive a high-frequency current. Electric wire 24a is electrically connected to one forceps piece 31 via a drive wire 13a, and electric wire 24b is electrically connected to the other forceps piece 31 via the drive wire 13b.

[0022] The sheath section 10 comprises a tubular outer sheath 11, a tubular inner sheath 12, and a pair of drive wires 13a and 13b. The total length L of the sheath section 10 is set in the range of approximately 1600 to 2000 mm, depending on the area of ​​biological tissue to be cauterized.

[0023] The outer sheath 11 consists of a flexible hollow tube, and a tube made of an insulating resin is used. The resin material used to form the outer sheath 11 is not particularly limited as long as it is an electrically insulating material, and polyethylene, polypropylene, polyvinyl chloride, polyurethane, polyamide, polyester, polycarbonate, polyethersulfone, fluororesin, etc. can be used.

[0024] The inner sheath 12 is made of a flexible hollow tube and, as shown in Figure 2, is inserted into the outer sheath 11 and is provided to rotate around its axis within the outer sheath 11. The inner sheath 12 is a coil sheath using a coil tube made of a tightly wound coil spring.

[0025] In this embodiment, a round wire coil tube is used as the coil tube constituting the inner sheath 12, which is made by tightly winding strands of metal round wire (wire material with a circular cross-section), such as stainless steel, in a spiral shape. However, a flat wire coil tube using strands with a rectangular cross-section, or a coil tube using strands with other cross-sectional shapes, may also be used. The inner sheath 12 also serves as a power transmission member for transmitting rotational force to rotate the pair of forceps pieces 31 around the sheath axis for adjusting their posture.

[0026] In this embodiment, a coil tube made of a single wire tightly wound in a spiral is used as the coil tube constituting the inner sheath 12, but a coil tube made of multiple wires tightly wound in a spiral in parallel in the radial or axial direction may also be used.

[0027] As shown in Figure 2, a pair of drive wires 13a and 13b are inserted into the inner sheath 12, and the drive wires 13a and 13b are able to slide (slide along the axial direction) within the inner sheath 12. The drive wires 13a and 13b are flexible and conductive wires, and their surfaces are each provided with an insulating coating to insulate them from each other. For the coatings provided on the surfaces of the drive wires 13a and 13b, for example, polytetrafluoroethylene (PTFE), which has excellent insulating properties, can be used. The drive wires 13a and 13b are power transmission members for transmitting the sliding force to open and close a pair of forceps pieces 31, and are also members (conducting paths) that constitute an electrical circuit for supplying high-frequency current so that each of the pair of forceps pieces 31 forms a bipolar electrode with opposing poles to each other. In this embodiment, a pair of drive wires 13a and 13b are used, both of which also function as conductive paths. However, it is also possible to use only one wire that serves as both a power transmission member and a conductive path as the drive wire, with a separate conductive path provided to form its opposite pole. Alternatively, the drive wire may be used solely as a power transmission member, with a separate pair of conductive paths provided.

[0028] In the operating section 20, the base 21 has a ring portion 21a and a guide portion 21b having a guide groove. The slider 22 is mounted on the base 21 so as to be slidable back and forth (up and down in Figure 1) along the guide portion 21b. A tip cap 23 is connected and fixed to the tip (distal end) of the base 21. The base 21, slider 22, and tip cap 23 are mainly made of insulating resin.

[0029] The proximal end of the outer sheath 11 is positioned in a through hole formed inside the tip cap 23, and the outer sheath 11 is separated from the tip of the base 21 and is rotatable relative to the base 21. The proximal end of the inner sheath 12 is fixed to the distal end of the base 21, and the proximal ends of the pair of drive wires 13a and 13b (arranged side by side with spacing in the depth direction of the paper in Figure 1) are fixed to the slider 22, respectively.

[0030] By sliding the slider 22 back and forth (up and down in Figure 1) relative to the base 21, the drive wires 13a and 13b can be slid in the axial direction within the inner sheath 12. Furthermore, by rotating the base 21 and slider 22 around the sheath axis, the inner sheath 12 and the drive wires 13a and 13b can be rotated around the axis relative to the outer sheath 11.

[0031] The configuration of the distal end of the bipolar hemostatic forceps 1 will be described with reference to Figures 3 to 7. Figure 3 is a perspective view showing the configuration of the distal end of the bipolar hemostatic forceps 1 in Figure 1. Figure 4 is a plan view showing the configuration of the distal end of the bipolar hemostatic forceps 1 in Figure 1, showing the gripping portions 31a of the pair of forceps pieces 31 in the open state. Figure 5 shows the gripping portions 31a of the pair of forceps pieces 31 in Figure 4 in the closed state. Figure 6 is a partial cross-sectional view showing the configuration of the distal end of the bipolar hemostatic forceps 1 in Figure 1, showing the gripping portions 31a of the pair of forceps pieces 31 in the open state. Figure 7 shows the gripping portions 31a of the pair of forceps pieces 31 in Figure 6 in the closed state.

[0032] In Figures 6 and 7, the distal end of the support member 32 beyond the base end 32b is shown with the arm portion 32a on the near side of the paper removed, while the proximal end of the support member 32 beyond the base end 32b is shown as a cross-section cut including the sheath axis (except for the drive wires 13a and 13b, which are shown in plan view). In the drawings, the X, Y, and Z axes are perpendicular to each other. The X axis is the rotation axis direction of the pair of forceps pieces 31 that open and close. The Y axis is perpendicular to the rotation axis of the pair of forceps pieces 31 that open and close, and the pair of forceps pieces 31 rotate in the YZ plane to perform the opening and closing operation of the gripping portion 31a. The Z axis is the axial direction of the sheath portion 10.

[0033] An outer sheath cap 11a is attached to the distal end of the outer sheath 11. As shown in Figures 6 and 7, the outer sheath cap 11a has a substantially cylindrical tubular portion 11a1 and a protruding edge portion 11a2 at its distal end that engages with the distal end of the outer sheath 11. The outer sheath cap 11a is fixed to the outer sheath 11 with the tubular portion 11a1 inserted into the opening at the distal end of the outer sheath 11.

[0034] As shown in Figures 6 and 7, a narrow-diameter portion 12b is formed at the distal end of the inner sheath 12, which has a smaller diameter than the proximal large-diameter portion 12a. The narrow-diameter portion 12b of the inner sheath 12 is inserted into the cylindrical portion 11a1 of the outer sheath cap 11a and is positioned to protrude distally (in the Z-axis direction) from the distal end of the outer sheath 11. Furthermore, a stepped portion 12c formed at the boundary between the large-diameter portion 12a and the narrow-diameter portion 12b of the inner sheath 12 abuts against the tip of the cylindrical portion 11a1 of the outer sheath cap 11a, thereby stabilizing the rotation of the inner sheath 12 within the outer sheath 11.

[0035] The treatment section 30 is formed in a forceps shape for grasping internal tissue and is generally composed of a forceps section having a pair of forceps pieces 31 that function as a pair of high-frequency electrodes for cauterizing internal tissue by passing a high-frequency current through it, a support member 32, and an insulating spacer 33. The pair of forceps pieces 31 constitute a pair of bipolar electrodes.

[0036] The support member 32 has a substantially cylindrical base end portion 32b with a flange portion, and a pair of arm portions 32a that protrude from the base end portion 32b in the Z-axis direction and face each other in the X-axis direction.

[0037] As shown in Figures 6 and 7, the base end 32b of the support member 32 is fixed to the distal end of the inner sheath 12 via a substantially cylindrical inner fixing member 34a and an outer fixing member 34b made of resin or the like. Specifically, the inner fixing member 34a is fitted inside the base end 32b of the support member 32, and the outer fixing member 34b is fitted outside the distal end of the inner sheath 12. The contact surfaces of the base end 32b of the support member 32, the inner sheath 12, the inner fixing member 34a, and the outer fixing member 34b are bonded and fixed to each other with adhesive, thereby fixing the support member 32 to the inner sheath 12.

[0038] The drive wires 13a and 13b, inserted into the inner sheath 12, are positioned to penetrate the lumen of the proximal end 32b of the support member 32. The distal end of one drive wire 13a is connected to the through-hole 31c1 of one forceps piece 31, and the distal end of the other drive wire 13b is connected to the through-hole 31c1 of the other forceps piece 31.

[0039] The distal end of the drive wire 13a has its insulating coating removed and is electrically connected to one of the forceps pieces 31, and similarly, the distal end of the drive wire 13b has its insulating coating removed and is electrically connected to the other forceps piece 31. Therefore, one forceps piece 31 is electrically connected to the electric wire 24a (see Figure 1) via the drive wire 13a, and the other forceps piece 31 is electrically connected to the electric wire 24b (see Figure 1) via the drive wire 13b.

[0040] As shown in Figures 3 to 5, fitting holes 32c are formed near the tips of the pair of arm portions 32a, penetrating inward and outward (in the X-axis direction). The shape of each fitting hole 32c of the pair of arm portions 32a is such that the shaft tip 33a2 of the shaft portion 33a of the insulating spacer 33, which will be described later, can be fitted into it. By fitting the shaft tip 33a2 of the insulating spacer 33 into each fitting hole 32c of the pair of arm portions 32a, the insulating spacer 33 is fixed to the pair of arm portions 32a. Furthermore, as will be described later, a through hole 33d is formed in the shaft portion 33a of the insulating spacer 33, and a pin 35 inserted through the through hole 33d is provided to close the fitting hole 32c.

[0041] The pair of forceps pieces 31 will be described with further reference to Figures 8 and 9. Figure 8 is a perspective view showing the forceps pieces 31 of the bipolar hemostatic forceps 1 of Figure 1. Figure 9 is a top view showing the forceps pieces 31 of Figure 8.

[0042] The pair of forceps pieces 31 are electrically insulated from each other by an insulating spacer 33 made of an insulating resin (e.g., polycarbonate) and are rotatably supported, and in this state are positioned between a pair of arm portions 32a of a support member 32. The pair of forceps pieces 31 are rotatable in the YZ plane about the same axis of rotation and are positioned so as to intersect each other (in a roughly X shape) around the axis of rotation.

[0043] In this embodiment, the pair of forceps pieces 31 are substantially identical in shape. Each forceps piece 31 is a longitudinally extending member integrally having a gripping portion 31a, a pivot portion 31b, and a connecting portion 31c, and is formed from a conductive metal material such as stainless steel.

[0044] The pivot portion 31b is the part of the support member 32 that has a pivot hole 31b3 which constitutes the axis of rotation for the arm portion 32a. The connecting portion 31c is provided on the proximal side in the longitudinal direction of the pivot portion 31b and is the part to which the distal end of the drive wire 13a or drive wire 13b is mechanically and electrically connected, and has a through hole 31c1 for attaching the drive wire 13a or drive wire 13b. The distal ends of the drive wires 13a and 13b are bent as appropriate and passed through the through holes 31c1 of the corresponding forceps pieces 31, thereby being locked to the connecting portion 31c. As a result, when the slider 22 is slid proximal to the base 21 in the operating section 20, the drive wires 13a and 13b are pulled proximal to the support member 32, and the pair of forceps pieces 31 rotate in the direction of closing the gripping portion 31a. Furthermore, in the operating unit 20, when the slider 22 is slid distally to the base 21, the drive wires 13a and 13b are pushed distally to the support member 32, causing the pair of forceps pieces 31 to rotate in the direction of opening the gripping portion 31a.

[0045] The gripping portion 31a is located further forward (distal) than the pivot portion 31b in the longitudinal direction and is a portion for gripping biological tissue as the target area for gripping. As shown in Figures 8 and 9, the gripping portion 31a has a flat surface portion 31a1, a pair of tip teeth 31a2 provided at the tip of the surface portion 31a1, and a plurality of surface teeth 31a3 provided on the surface portion 31a1.

[0046] The flat portion 31a1 of the gripping portion 31a is configured such that, when the gripping portions 31a of the pair of forceps pieces 31 are closed (see Figures 5 and 7), the flat portion 31a1 of one forceps piece 31 and the flat portion 31a1 of the other forceps piece 31 are substantially parallel to each other and face each other. The flat portion 31a1 of the gripping portion 31a has a pair of sides that are set substantially parallel to each other, and the longitudinal tip side has a smooth, rounded curved shape.

[0047] The pair of tip teeth 31a2 and the multiple planar teeth 31a3 of the gripping portion 31a are erected on the flat surface of the planar portion 31a1, facing the opposing forceps pieces 31. When the gripping portions 31a of the pair of forceps pieces 31 are closed (see Figures 5 and 7), the tip teeth 31a2 and planar teeth 31a3 of one forceps piece 31 face each other. In this embodiment, as will be described later, even when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent by the operating portion 20, the gripping portions 31a of the pair of forceps pieces 31 do not come into contact, and the opposing tip teeth 31a2 and planar teeth 31a3 are separated by a predetermined gap.

[0048] The tip teeth 31a2 are provided in pairs at the longitudinal tip of the forceps piece 31. The flat teeth 31a3 have a shape that extends in the width direction (X-axis direction) of the gripping portion 31a and are arranged in parallel along the longitudinal direction of the forceps piece 31. In this embodiment, each flat tooth 31a3 has the shape of a triangular prism with a right-angled isosceles triangle as its base, and three flat teeth 31a3 are arranged in parallel at equal intervals along the longitudinal direction. However, the shape and number of flat teeth 31a3 are not limited to this, and the multiple flat teeth 31a3 do not necessarily have to be arranged at equal intervals.

[0049] As shown in Figures 8 and 9, the pivot portion 31b has a connecting portion 31b1 connected to the gripping portion 31a and a thickened portion 31b2 in which the shaft hole 31b3 is formed. As shown in Figure 9, the connecting portion 31b1 of the pivot portion 31b is connected to the gripping portion 31a at an off-center position from the center in the width direction (X-axis direction) of the gripping portion 31a. This creates a space between the pivot portions 31b of the pair of forceps pieces 31 in which an insulating spacer 33 can be placed when the gripping portions 31a of the pair of forceps pieces 31 are arranged facing each other.

[0050] The connecting portion 31b1 of the pivot portion 31b has a curved surface that smoothly connects to the flat portion 31a1 of the gripping portion 31a. As will be described later, when the gripping portions 31a of the pair of forceps pieces 31 are closed by the operating portion 20, the curved surface of the connecting portion 31b1 of the forceps piece 31 comes into contact with the end face 33g1 of the support projection 33g of the insulating spacer 33, preventing the pair of forceps pieces 31 from rotating further in the closing direction, thereby restricting the closing operation of the gripping portion 31a.

[0051] A shaft hole 31b3 is formed in the thickened portion 31b2 of the shaft support portion 31b. The shaft hole 31b3 formed in the thickened portion 31b2 has a substantially circular cross-section, and a notch 31b4 is formed on a part of the inner circumferential surface of the shaft hole 31b3, extending radially outward from the axis. As shown in Figures 6 and 7, a projection 33f formed on the shaft portion 33a of the insulating spacer 33 is loosely fitted into the notch 31b4.

[0052] The insulating spacer 33 will be described with further reference to Figures 10 and 11. Figure 10 is a perspective view showing the insulating spacer 33 of the bipolar hemostatic forceps 1 of Figure 1. Figure 11 is a plan view showing the insulating spacer 33 of Figure 10.

[0053] The insulating spacer 33 is made of an insulating material such as resin, and is a member that pivotally supports a pair of forceps pieces 31 in a state where they are electrically insulated from each other. As shown in Figures 10 and 11, the insulating spacer 33 generally has a substantially plate-shaped spacer portion 33c and a pair of substantially cylindrical shaft portions 33a that protrude from both sides of the spacer portion 33c. The pair of shaft portions 33a are symmetrical in shape and are arranged coaxially. The through holes 33d in the center of the pair of shaft portions 33a pass through the spacer portion 33c and communicate with each other.

[0054] As shown in Figure 10, the shaft portion 33a is composed of a shaft base portion 33a1 located on the base end side of the shaft portion 33a that protrudes from the surface of the spacer portion 33c, and a shaft tip portion 33a2 located on the tip side of the shaft portion 33a. The outer diameter of the shaft portion 33a is set to be slightly smaller than the inner diameter of the shaft hole 31b3 of the forceps piece 31 so that it can be rotatably inserted into the shaft hole 31b3 of the forceps piece 31. The shaft portion 33a is inserted into the shaft hole 31b3 of the forceps piece 31, and the forceps piece 31 rotates around the shaft base portion 33a1.

[0055] On the other hand, the shaft tip portion 33a2 is shaped to fit into the fitting hole 32c of the arm portion 32a. For example, the shaft tip portion 33a2 is formed to have a circular (approximately oval) cross-section with a part of it cut out, and by fitting it into the fitting hole 32c of the arm portion 32a which is formed to a similar shape, the insulating spacer 33 is fixed to the pair of arm portions 32a without rotating.

[0056] Furthermore, the shaft base end 33a1 has a projection 33f that protrudes radially outward in a cross section perpendicular to the axis of the shaft base end 33a1. This projection 33f is formed to be movable within a notch 31b4 formed in the shaft hole 31b3 when the shaft portion 33a is inserted into the shaft hole 31b3 of the forceps piece 31.

[0057] The spacer portion 33c is integrally provided with a support projection 33g protruding from one side and another support projection 33g protruding from the other side. These support projections 33g have the function of defining the distance between the pair of arm portions 32a of the support member 32.

[0058] Furthermore, the support projection 33g functions as a rotation restricting part that contacts the forceps piece 31 when the gripping portions 31a of the pair of forceps pieces 31 are closed, thereby restricting the rotation of the forceps piece 31 so that it does not rotate further in the closing direction. Specifically, the end face 33g1 of the support projection 33g is configured to contact the connecting portion 31b1 of the pivot portion 31b of the forceps piece 31 when the gripping portions 31a of the pair of forceps pieces 31 are closed. Even when the gripping portions 31a of the pair of forceps pieces 31 are closed to the maximum extent by the operating part 20, the connecting portion 31b1 of the forceps piece 31 contacts the end face 33g1, and the rotation of the forceps piece 31 can be restricted so that it does not rotate further from the state in which the gripping portions 31a of the pair of forceps pieces 31 are substantially parallel.

[0059] Referring to Figure 12, the gap between the gripping portions 31a of the pair of forceps pieces 31, which is formed when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent by the operating section 20, will be explained. Figure 12 is a partially enlarged view showing the distal end of the bipolar hemostatic forceps 1 of Figure 7.

[0060] As described above, in this embodiment, the bipolar hemostatic forceps 1 allows each of the integral forceps pieces 31 to be rotated relative to the support member 32 by operating the operating unit 20, thereby opening and closing the gripping portions 31a of the pair of forceps pieces 31. When the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent by the operating unit 20, the gripping portions 31a of the pair of forceps pieces 31 face each other so as to be substantially parallel, and the gripping portions 31a of the pair of forceps pieces 31 do not come into contact with each other, creating a gap between the gripping portions 31a.

[0061] In this embodiment, the pair of forceps pieces 31 are substantially identical in shape, and each forceps piece 31 is set so that the height from the flat portion 31a1 to the tip of the protruding tooth 31a2 and the tip of the protruding tooth 31a3 of the flat portion are approximately the same height H (see Figure 12).

[0062] When the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent, the gripping portions 31a of the pair of forceps pieces 31 become approximately parallel to each other, and as shown in Figure 12, the tips of the opposing tip teeth 31a2 and the tips of the flat teeth 31a3 are in close proximity. However, at this time, the tip teeth 31a2 and the flat teeth 31a3 do not come into contact with each other but are separated by a predetermined gap G (see Figure 12).

[0063] If the gap between the gripping portions 31a of the pair of forceps pieces 31 is too narrow, there is a possibility of a short circuit and electrical conduction between the pair of forceps pieces 31, and if the gap is too wide, there is a possibility that the tissue cannot be gripped stably. Taking this into consideration, it is preferable to set the gap between the gripping portions 31a of the pair of forceps pieces 31 so as to ensure that a short circuit does not occur between the pair of forceps pieces 31, and so as to ensure that the gripping force of the gripping portions 31a of the pair of forceps pieces 31 is appropriately secured, for example, it can be set to 0.07 to 0.2 mm.

[0064] The heights of each tip protrusion 31a2 and each flat portion protrusion 31a3 may be different. For example, the height of each tip protrusion 31a2 may be greater than the height of each flat portion protrusion 31a3. In this case, the area where the gripping portions 31a of a pair of forceps pieces 31 that are closed to the maximum extent by operation by the operating unit 20 are closest to each other (for example, the opposing tip protrusions 31a2) is appropriately adjusted as the gap between the gripping portions 31a of the pair of forceps pieces 31.

[0065] In this embodiment, the support projection 33g of the insulating spacer 33 functions as a rotation restricting part that restricts the closing movement of the gripping portion 31a of the pair of forceps pieces 31. As shown in Figure 11, the support projection 33g is formed so that its end face 33g1 protrudes beyond the central surface C of the insulating spacer 33 (the ZX surface including the rotation axis center of the forceps piece 31) toward the contacting forceps piece 31. As a result, the end face 33g1 of the support projection 33g is positioned at a predetermined distance D away from the central surface C of the insulating spacer 33.

[0066] When the gripping portions 31a of the pair of forceps pieces 31 are closed by the operating unit 20, the connecting portion 31b1 of the pair of forceps pieces 31 abuts against the end faces 33g1 of the support projections 33g that protrude from one and the other surfaces of the spacer portion 33c, respectively, restricting the rotation of the pair of forceps pieces 31 and preventing the gripping portions 31a from coming any closer together. As a result, contact between the gripping portions 31a of the pair of forceps pieces 31 is reliably prevented, thus preventing short circuits between the pair of forceps pieces 31. Furthermore, even when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent, the tissue can be forced into the gap between the gripping portions 31a by pressing the gripping portions 31a of the pair of forceps pieces 31 against the tissue, thereby allowing the tissue to be cauterized.

[0067] The gap G when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent can be appropriately set by adjusting the distance D between the end face 33g1 of the support projection 33g and the central surface of the insulating spacer 33. For example, the insulating spacer 33 can be manufactured such that the distance D between the end face 33g1 of the support projection 33g and the central surface of the insulating spacer 33 is the sum of the height H from the flat portion 31a1 to the tip of the protruding tooth 31a2 and the tip of the protruding tooth 31a3 of the flat portion and half of the desired gap G (D = H + G / 2). The configuration for forming a gap between the gripping portions 31a of the pair of forceps pieces 31 when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent by the operating portion 20 is not particularly limited, but as in this embodiment, by providing a rotation restricting portion on the insulating spacer 33, the gap between the gripping portions 31a can be set accurately and easily.

[0068] In this embodiment, when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent by the operating section 20, a gap is formed between the gripping portions 31a. Therefore, compared to the case where the gripping portions 31a of the pair of forceps pieces 31 are allowed to contact each other, the gripping force of the gripping portions 31a to hold the tissue may decrease. However, by providing multiple flat protrusions 31a3 to increase the gripping force of the gripping portions 31a to hold the tissue, this decrease in gripping force can be compensated for. When tissue is gripped by the gripping portions 31a, the flat protrusions 31a3 bite into the tissue, concentrating stress on the tissue. Therefore, the gripping force of the gripping portions 31a to hold the tissue can be increased compared to the case where the flat protrusions 31a3 are not provided. In addition, by providing the flat protrusions 31a3, the contact area between the pair of forceps pieces 31 and the tissue increases, so the frictional force on the tissue is increased, which can also suppress the slippage of the gripped tissue.

[0069] The operation of the bipolar hemostatic forceps 1, which is one of the bipolar forceps-type treatment instruments in this embodiment, will be described below.

[0070] The bipolar hemostatic forceps 1 in this embodiment is inserted into the body via an endoscope and comprises a sheath portion 10 through which drive wires 13a and 13b are inserted, an operating portion 20 for sliding the drive wires 13a and 13b relative to the sheath portion 10, a support member 32 provided at the distal end of the sheath portion 10, and a pair of forceps pieces 31 rotatably attached to the support member 32, which function as a pair of bipolar high-frequency electrodes and have gripping portions 31a that open and close in conjunction with the sliding of the drive wires 13a and 13b relative to the sheath portion 10. Furthermore, when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent by the operating portion 20, the gripping portions 31a of the pair of forceps pieces 31 face each other so as to be substantially parallel, and a gap is formed between the gripping portions 31a of the pair of forceps pieces 31 without the gripping portions 31a of the pair of forceps pieces 31 contacting each other.

[0071] With the above configuration, contact between the gripping portions 31a of the pair of forceps pieces 31 can be reliably avoided, preventing short circuits between the pair of forceps pieces 31. This allows for proper cauterization of tissue while suppressing excessive heat generation, providing a bipolar hemostatic forceps 1 with excellent safety and reliability. Furthermore, even when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent, the tissue can be properly cauterized by pressing the gripping portions 31a of the pair of forceps pieces 31 against the tissue and allowing the tissue to enter the gap between them.

[0072] In this embodiment, the bipolar hemostatic forceps 1 is fixed to a support member 32 and includes an insulating spacer 33 that rotatably supports a pair of forceps pieces 31 while electrically insulating them from each other. The insulating spacer 33 has a support projection 33g (rotation restricting part) that contacts the pair of forceps pieces 31 when the gripping parts 31a of the pair of forceps pieces 31 are closed by the operating part 20, thereby restricting the closing operation of the gripping parts 31a of the pair of forceps pieces 31. When the gripping parts 31a of the pair of forceps pieces 31 are closed to the maximum extent by the operating part 20, the pair of forceps pieces 31 may contact the support projection 33g, forming a gap between the gripping parts 31a of the pair of forceps pieces 31 in the fully closed state.

[0073] With the above configuration, the rotation restricting portion provided on the insulating spacer 33 creates an appropriate gap between the gripping portions 31a of the pair of forceps pieces 31 when they are in their most closed state, thereby reliably preventing contact between the pair of forceps pieces 31.

[0074] In this embodiment, the bipolar hemostatic forceps 1 may have a plurality of flat protruding teeth 31a3 (protruding teeth) on the gripping portions 31a of a pair of forceps pieces 31 that face each other.

[0075] With the above configuration, even when a gap is formed between the gripping portions 31a of a pair of forceps pieces 31 in their most closed state, the multiple flat protrusions 31a3 (protrusions) provided on the opposing surfaces of the gripping portions 31a of the pair of forceps pieces 31 suppress the slippage of the tissue to be gripped, allowing for stable gripping of the tissue.

[0076] In this embodiment, the bipolar hemostatic forceps 1 may have a gap of 0.07 to 0.2 mm between the gripping portions 31a of the pair of forceps pieces 31 when the gripping portions 31a of the pair of forceps pieces 31 are closed to their maximum extent.

[0077] If the gap between the gripping portions 31a of the pair of forceps pieces 31 is too narrow, the pair of forceps pieces 31 may short-circuit, and if the gap is too wide, it may not be possible to stably grasp the tissue. By setting the gap between the gripping portions 31a of the pair of forceps pieces 31 to 0.07 to 0.2 mm as in the above configuration, it is possible to realize a well-balanced bipolar hemostatic forceps 1 that ensures that the pair of forceps pieces 31 do not short-circuit and that appropriate gripping force is secured.

[0078] The embodiments described above are provided to facilitate understanding of the present invention and do not limit it. The components disclosed in the embodiments described above are intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0079] 1. Bipolar hemostatic forceps (bipolar forceps-type treatment instrument) 10 Sheath section 11 Outer Sheath 11a Outer Sheath Cap 11a1 Cylindrical part 11a2 Edge 12 Inner sheath 12a Large diameter part 12b Narrow diameter part 12c Step section 13a, 13b drive wires 20 Control section 21 Base 21a Ring section 21b Guide section 22 Sliders 23 Tip cap 24 plugs 24a, 24b wire 30 Treatment Department 31 Forceps piece 31a Grip part 31a1 Flat part 31a2 Tip convex tooth 31a3 Convex tooth on flat surface (convex tooth) 31b Axial support 31b1 Connection part 31b2 Thick part 31b3 shaft hole 31b4 Notch 31c connection 31c1 through hole 32 Support member 32a Arm section 32b Proximal end 32c mating hole 33 Insulating Spacer 33a Shaft 33a1 Shaft base end 33a2 Shaft tip 33c Spacer section 33d Through hole 33f Protrusion 33g support protrusion 33g1 End face 34a Inner fixing member 34b Outside fixing member 35 pins

Claims

1. A bipolar forceps-type treatment instrument that is inserted into the body via an endoscope, The sheath portion through which the drive wire is inserted, An operating unit for sliding the drive wire relative to the sheath portion, A support member provided at the distal end of the sheath portion, The system comprises a pair of forceps pieces that are rotatably attached to the support member, function as a pair of bipolar high-frequency electrodes, and have gripping portions that open and close in conjunction with the sliding of the drive wire relative to the sheath portion, A bipolar forceps-type treatment instrument characterized in that, when the gripping portions of the pair of forceps pieces are closed to the maximum extent by the operating unit, the gripping portions of the pair of forceps pieces face each other so as to be substantially parallel, and a gap is formed between the gripping portions of the pair of forceps pieces without the gripping portions of the pair of forceps pieces touching each other.

2. The support member is fixed to the aforementioned support member and includes an insulating spacer that rotatably supports the pair of forceps pieces while electrically insulating them from each other, The insulating spacer has a rotation restricting portion that contacts the pair of forceps pieces when the gripping portions of the pair of forceps pieces are closed by the operating portion, thereby restricting the closing operation of the gripping portions of the pair of forceps pieces. The bipolar forceps type treatment instrument according to claim 1, characterized in that when the gripping portions of the pair of forceps pieces are closed to the maximum extent by the operating portion, the pair of forceps pieces come into contact with the rotation restricting portion, and the gap is formed between the gripping portions of the pair of forceps pieces in the fully closed state.

3. The bipolar forceps-type treatment instrument according to claim 1 or 2, characterized in that the gripping portions of the pair of forceps pieces have a plurality of protruding teeth on surfaces facing each other.

4. The bipolar forceps type treatment instrument according to claim 1 or 2, characterized in that the gap between the gripping portions of the pair of forceps pieces, formed when the gripping portions of the pair of forceps pieces are closed to their maximum extent, is 0.07 to 0.2 mm.

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