Endoscopic biopsy forceps

[0002] The present invention relates to endoscopic biopsy forceps that is passed into a forceps channel in an endoscope to collect a tissue specimen to be analyzed by biopsy.

[0003] Endoscopic biopsy forceps generally comprise a sheath that is inserted into or removed out of a forceps channel in an endoscope, a manipulating wire provided to extend through the sheath and a pair of forceps cups that are provided at the distal end of the sheath and which are driven to open or close like beaks by advancing or retracting the manipulating wire in the axial direction. The forceps cups are formed in substantially symmetrical shapes and their opposed open ends have sharp blade-like edges.

[0004] To collect a tissue to be analyzed by biopsy, the operator pulls the manipulating wire toward himself so that the forceps cups are closed, whereupon tissue severing edges at the open ends of the forceps cups sever the tissue and the desired tissue specimen is collected in the forceps cups.

[0005] When the tissue pinched between the forceps cups is being severed, the forceps cups receive an irregular strong force, and a lateral displacement or a tilt, although small in amount, will occur in the forceps cups as they move like beaks.

[0006] As a result, even when the two forceps cups are completely closed, heir tissue severing edges do not meet perfectly but often fail to sever the tissue neatly to the last bit.

[0007] To deal with this case, the operator frequently tears off the tissue by pulling the biopsy forceps toward himself as it is pinched between the forceps cups but then the mucosa of the patient is damaged to cause undue bleeding.

[0008] An object, therefore, of the present invention is to provide endoscopic biopsy forceps with which the tissue to be analyzed by biopsy can be severed positively to the last bit so that a specimen of the tissue can be collected with minimum occurrence of bleeding.

[0009] To achieve the above-noted object, the present invention provides a novel arrangement for endoscopic biopsy forceps, in which forceps cups has opposed open ends slightly different in size, so that when said forceps cups are closed, the open end of one forceps cup rests into the open end of the other forceps cup.

[0010] The present invention further provides a novel arrangement for endoscopic biopsy forceps, in which forceps cups has opposed open ends and tissue severing edges which are formed on the open ends and slightly different in size, so that when said forceps cups are closed, the tissue severing edge of one forceps cup rests into the tissue severing edge of the other forceps cup.

[0011] In accordance with the present invention, when a tissue pinched between two forceps cups is being severed, the cups engage each other such that a tissue severing edge of the smaller cup is guided to rest inward of the tissue severing edge of the larger cup. As a result, the tissue can be severed positively to the last bit so that the desired specimen of the tissue is collected with minimum occurrence of bleeding.

[0012] The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 10-330360 (filed on Nov. 20, 1998) and Hei. 11-293474 (filed on Oct. 15, 1999), which are expressly incorporated herein by reference in their entireties.

[0013] FIG. 1 is a longitudinal section of the distal end portion of endoscopic biopsy forceps according to an embodiment of the invention.

[0014] FIG. 2 is section II—II of FIG. 1 or a cross section of the distal end portion of the same endoscopic biopsy forceps.

[0015] FIG. 3 is a longitudinal section of the distal end portion of the same endoscopic biopsy forceps as it is used in practice.

[0016] FIG. 4 is a cross section of the distal end portion of the same endoscopic biopsy forceps as it is used in practice.

[0017] FIG. 5 is a side view of the same endoscopic biopsy forceps.

[0018] FIG. 6 is an enlarged longitudinal section showing a state that forceps cups according to a second embodiment are closed completely.

[0019] FIG. 7 is an enlarged longitudinal section showing a state that forceps cups according to a third embodiment are closed completely.

[0020] FIG. 8 is an enlarged longitudinal section showing a state that forceps cups according to a fourth embodiment are closed completely.

[0021] FIG. 9 is an enlarged longitudinal section showing a state that forceps cups according to a fifth embodiment are closed completely.

[0022] FIG. 10 is an enlarged longitudinal section showing a state that forceps cups according to a sixth embodiment are closed completely.

[0023] FIG. 11 is an enlarged longitudinal section showing a state that forceps cups according to a seventh embodiment are closed completely.

[0024] FIG. 12 is an enlarged longitudinal section showing a state that forceps cups according to an eighth embodiment are closed completely.

[0025] FIG. 13 is an enlarged longitudinal section showing a state that forceps cups according to a ninth embodiment are closed completely.

[0026] Preferred embodiments of the invention will be described below with reference to the accompanying drawings.

[0027] FIG. 5 shows the endoscopic biopsy forceps of the invention. The endoscopic biopsy forceps has a flexible sheath 1 that is to be inserted into or removed out of a forceps channel in an endoscope (not shown) and which typically comprises a closely wound coil pipe. The flexible sheath 1 has a manipulating wire provided to extend through it over the entire length such that the wire is capable of moving back and forth along the axis of the sheath 1. A closely wound coil pipe is not the sole example of the sheath 1; the sheath 1 may be constructed by a closely wound coil pipe covered with a flexible tube, or any other suitable construction may be employed.

[0028] The basal end of the sheath 1 (which is closer to the operator) is coupled to a manipulating portion 20 for moving the manipulating wire back and forth. The distal end of the sheath 1 is coupled to a tip activating portion 10 that is driven with the manipulating wire.

[0029] FIG. 1 shows the tip activating portion 10 which comprises a link mechanism 13 of a known construction that is driven with the manipulating wire 2, and a pair of forceps cups 11 and 12 that are adapted to pivot about a support shaft 14 so that they open or close like beaks. When they open, the forceps cups 11 and 12 come to the positions indicated by the two-dotted chain line.

[0030] The open ends of the two forceps cups 11 and 12 are shaped to have oblong cross sections that face each other when the two cups are closed. Those open ends have sharp edges 11aand 12afor severing a tissue.

[0031] The open ends of the forceps cups 11 and 12 are almost symmetrical in shape but slightly different in size such that when they are closed, the peripheral or edge portion of the open end of the first forceps cup 11 is in contact with a slope of the open end of the second forceps cup 12 so that the tissue severing edge 11aof the first forceps cup 11 rests inward of the tissue severing edge 12aof the second forceps cup 12.

[0032] This relationship holds not only in the longitudinal direction but also in the circumferential direction; as shown in FIG. 2 which is section II—II of FIG. 1, the tissue severing edges 11aof the first forceps cup 11 rest inward of the tissue severing edges 12aof the second forceps cup 12 over the whole peripheries of the first and second forceps cups 11 and 12.

[0033] The endoscopic biopsy forceps having the construction described above is used in the following way. With the forceps cups 11 and 12 closed, the sheath 1 is inserted into the forceps channel of an endoscope (not shown). When a diseased part is detected, the cups are opened and pressed onto it. Thereafter, the manipulating wire 2 is pulled to close the cups, whereupon the tissue severing edges 11aand 12aof the cups sever the tissue of the diseased part.

[0034] When the two forceps cups 11 and 12 are completely closed, the tissue severing edge 11aof the first cup 11 rests inward of the tissue severing edge 12aof the second cup 12 as shown in FIGS. 3 and 4 which are a longitudinal and a cross section, respectively, of the cups.

[0035] When the tissue pinched between the two cups is being severed, an irregular strong force acts on the cups to develop a lateral displacement or a tilt. In the present invention, the two forceps cups engage each other such that the tissue severing edge 11aof the smaller cup 11 is guided to rest inward of the tissue severing edge 12aof the larger cup 12; as a result, a shear action occurs between those tissue severing edges 11aand 12a, and the tissue to be analyzed by biopsy is severed neatly to the last bit so that the desired specimen of the tissue 100 is collected within the closed cups.

[0036] Therefore, no part of the tissue is forcibly pulled or torn off and the mucosa of the patient is not damaged to cause undue bleeding. What is more, the tissue severing edges 11aand 12aof the forceps cups 11 and 12 do not bump each other, so they stand up to prolonged use without nicking or wear.

[0037] Note that the present invention should not be limited to the embodiment described above, and can be modified in various ways.

[0038] For example, the pair of forceps cups 11 and 12 can be formed into various mutual configuration.

[0039] For example, as shown in FIGS. 6 to 8, one or both of the open ends of the forceps cup 11 and 12 may be planar, may have a small planar surface contiguous to the distal end of a slope, etc.

[0040] In each of the embodiments as well, when the pair of forceps cups are closed, the peripheral portion of the open end of the first forceps cup 11 is in contact with the slope of the open end of the second forceps cup 12.

[0041] Further, as shown in FIGS. 9 to 11, the forceps cups 11 and 12 may be arranged such that when the pair of forceps cups 11 and 12 are being closed, the periphery of the open end of the first forceps cup 11 is slidingly contacted with the inner peripheral surface of the open end of the second forceps cup 12. Moreover, one or both of the open ends of the forceps cups 11 and 12 may be formed into a blade, a plate or a combination of them.

[0042] As shown in FIGS. 12 and 13, the pair of the forceps cups 11 and 12 may be constructed to have the tissue severing edges 11aand 12aslightly different in size from each other while the open ends of the forceps cups 11 and 12 are identical in size. In these embodiments, the tissue severing edge 12aof the one forceps cup 12 rests inward of the tissue severing edge 11aof the other forceps cup 12.