Treatment accessories for endoscope

Abstract: There is provided a treatment accessory for an endoscope. The treatment accessory is inserted in or removed from a forceps channel of the endoscope through an inlet of the forceps channel. The treatment accessory has a treatment device, a flexible shaft, the treatment device being provided at a first end of the flexible shaft. The flexible shaft is provided with a marking at a predetermined portion thereof. The treatment device is located at a predetermined position inside the forceps channel when a predetermined portion of the marking is located at the inlet of the forceps channel.

Description: The present invention relates to treatment accessories for an endoscope as, for instance, described in US-A-4 982 727. During use, a treatment accessory is inserted in a forceps channel of the endoscope, however, as the treatment accessory is being inserted through the forceps channel of the endoscope, before the distal end of the treatment accessory appears in an observing field of the endoscope, the distal end will have already been extended from the end of the forceps channel by a certain amount. Since a treatment device such as a forceps device is connected to the distal end of the treatment accessory, if the treatment accessory is pushed and extended from the forceps channel excessively, the treatment accessory may damage a mucous layer inside a human cavity. In a conventional treatment accessory, the above problem is prevented, by providing an index mark on a manipulation portion of the treatment accessory such that the extending amount of the treatment accessory is recognized. An example of such a treatment accessory is disclosed in JP Utility Model Provisional Publication SHO 52-158589, and JP Utility Model Provisional Publication SHO 61-203009 corresponding to the preamble of claim 1. However, since the viscera (human tissue) or the like are continuously moving, once the affected part comes into the observing field, it is preferable that the treatment accessory be pushed quickly through the forceps channel. In this case, even though an index mark is formed on the treatment accessory, in a quick insertion the treatment accessory may be inserted more than intended and the viscera (human tissue) may be damaged. Further, since there are various endoscopes having different lengths of forceps channels, the treatment accessory is generally formed to have a length that is appropriate for use in an endoscope having a forceps channel of a particular length. Accordingly, a plurality of treatment accessories which have different lengths must be available. However, having a plurality of treatment accessories for endoscopes having different forceps channel lengths is not economical. A long treatment accessory may also be used for an endoscope having a shorter forceps channel, however, if the treatment accessory is relatively long with respect to the forceps channel, there is a risk that when the treatment accessory is inserted in the forceps channel, the treatment accessory may be inserted too far and may damage tissue inside a body. Further to the above, the treatment accessory should be removed from the forceps channel as soon as the affected part has been treated. However, while the treatment accessory is being removed (pulled out of the forceps channel), it is difficult to judge the length of the treatment accessory, such that, if the treatment device is removed quickly, the flexible shaft may jump on exiting the forceps channel such that a collected sample or other substance may be dislodged and sprinkled around the room. A treatment accessory described in WO-A-97/24988 (not prepublished) solves this latter problem by a marking on the flexible shaft near its distal end. This marking can be observed by the user when the flexible shaft is removed from the forceps channel so that it can be slowly pulled out as soon as the marking appears at the channel inlet. It is therefore an object of the present invention to provide an improved treatment accessory that can be inserted in the forceps channel quickly without damaging the tissue in the human cavity. A further object of the invention is to provide an improved treatment accessory which can be used in various endoscopes having forceps channels of different lengths while also allowing a quick insertion of the treatment accessory into the forceps channel of the endoscope. Yet a further object of the invention is to provide an improved treatment accessory which may be removed from a forceps channel quickly without risk of dislodging a collected sample or spraying tissue or the like around the removal area. For the above objects, according to the invention, there is provided a treatment accessory for an endoscope, the treatment accessory having the features of the independent claim, advantageous further developments being described in the dependent claims. At least a part of an outer diameter of the ring-like member could be greater than an inner diameter of the forceps channel. Alternatively, an outer diameter of the ring-like member could be made smaller than an inner diameter of the forceps channel. Further, the flexible shaft may be provided with at least one position indicating area, which indicates an initial position of the ring-like member. Further optionally, at least one of a color, thickness, texture, and a shape of the position indicating area may be different from the other portion of the flexible shaft. Further, the flexible shaft may be provided with a plurality of position indicating areas corresponding to a plurality of forceps channels having different lengths. In this case, the plurality of position indicating areas could be made different from each other by at least one of a color, texture, thickness, and a shape. Still optionally, the flexible shaft may be a coil shaft formed from wound coils, and the marking may be formed by a tube member covering the coil shaft. It should be noted that the tube member is made from resin. The ring-like member may be formed from elastic material, the inner diameter of the slidable member being smaller than an outer diameter of the shaft. Furthermore, the shaft may be provided with a marking which indicates a position where the ring-like member is to be initially located. Further alternatively, the ring-like member may be formed to have a cylindrical shape. Optionally, the ring-like member is further provided with a flange portion which has a greater diameter than the inner diameter of the inlet of the forceps channel. Further optionally, the ring-like member may be formed to have substantially a cylindrical shape, a diameter of an end portion of the cylindrical shape being smaller than a diameter of a central portion of said cylindrical shape. The invention will now be further described with reference to the drawings wherein Figs. 1 to 4 show various endoscopes having various lengths; Fig. 5 is a schematic perspective view of an endoscope; Fig. 6 is a cross-section of a forceps tap of the endoscope of Fig. 5; Fig. 7 shows a treatment accessory according to an embodiment of the invention; Fig. 8 is a cross-section of a slidable ring of the treatment accessory of Fig. 7; Fig. 9 shows the treatment accessory of Fig. 7 when inserted in a forceps channel of the endoscope of Fig. 5; Fig. 10 shows a treatment accessory according to a second embodiment of the invention when inserted in a forceps channel of the endoscope of Fig. 5; Fig. 11 shows a treatment accessory according to a third embodiment of the invention; Fig. 12 shows a cross-section of a slidable ring of a treatment accessory according to a fourth embodiment of the invention; Fig. 13 shows a cross-section of a slidable ring of a treatment accessory according to a fifth embodiment of the invention; Fig. 14 shows a cross-section of a slidable ring of a treatment accessory according to a sixth embodiment of the invention; Fig. 15 shows a cross-section illustrating the use of the slidable ring of Fig. 14; Fig. 16 shows a slidable member of a treatment accessory according to a seventh embodiment of the invention; Fig. 17 shows a cross-section of a slidable member of a treatment accessory according to an eighth embodiment of the invention; Fig. 18 shows a cross-section of a ring and a shaft of a treatment accessory according to a ninth embodiment of the invention; Fig. 19 shows a cross-section of a ring and a shaft of a treatment accessory according to a tenth embodiment of the invention; Fig. 20 shows a treatment accessory according to an eleventh embodiment of the invention; Fig. 21 shows the treatment accessory of Fig. 20 inserted in the endoscope of Fig. 1; Fig. 22 shows the treatment accessory of Fig. 20 inserted in the endoscope of Fig. 2; Fig. 23 shows the treatment accessory of Fig. 20 inserted in the endoscope of Fig. 3. Figs. 1 through 4 show four different endoscopes 10, 10A, 10B and 10C. The endoscope 10 includes an insertion section 11, the length of which is L1. The proximal end of the insertion section 11 is connected to a manipulation unit 14. A forceps channel 16 is formed through the entire length of the insertion section 11, and in the manipulation unit 14, from an inlet 17 to an outlet 18. The length of the forceps channel 16 at a portion from the inlet 17 to a position where the manipulation unit 14 and the insertion section 11 is connected is G. The sum of the lengths L1 and G is equal to the length L of the forceps channel 16. Fig. 2 shows the endoscope 10A, which has a substantially similar structure to that shown in Fig. 1. The second endoscope 10A includes an insertion section 11A having a length L2. The proximal end of the insertion section 11A is connected to a manipulation unit 14A. A forceps channel 16A is formed through the entire length of the insertion section 11A, and in the manipulation unit 14A, from an inlet 17A to an outlet 18A. The length of the forceps channel 16A at a portion from the inlet 17A to a position where the manipulation unit 14A and the insertion section 11A is connected is G. Note that the only substantial difference of the endoscope 10A with respect to the endoscope 10 is the length L2 of the insertion section 11A. The third endoscope 10B shown in Fig. 3 includes an insertion section 11B having a length L3. The proximal end of the insertion section 11B is connected to a manipulation unit 14B. A forceps channel 16B is formed through the entire length of the insertion section 11B, and in the manipulation unit 14B, from an inlet 17B to an outlet 18B. The length of the forceps channel 16B at a portion from the inlet 17B to a position where the manipulation unit 14B and the insertion section 11B is connected is G. Note that the only substantial difference of the endoscope 10B with respect to the endoscope 10 is the length L3 of the insertion section 11B. The fourth endoscope 10C shown in Fig. 4 includes an insertion section 11C having a length L4. The proximal end of the insertion section 11C is connected to a manipulation unit 14C. A forceps channel 16C is formed through the entire length of the insertion section 11C, and in the manipulation unit 14C, from an inlet 17C to an outlet 18C. The length of the forceps channel 16C at a portion from the inlet 17C to a position where the manipulation unit 14C and the insertion section 11C is connected is G. Note that the only substantial difference of the endoscope 10C with respect to the endoscope 10 is the length L4 of the insertion section 11C. The relationship between the lengths of the insertion sections 11, 11A, 11B and 11C is expressed as: L1 < L4 < L2 < L3. The lengths of the forceps channels 16, 16A, 16B and 16C are (L1 + G), (L2 + G), (L3 + G) and (L4 + G), respectively, which are different from each other. Fig. 5 is a schematic perspective view of the endoscope 10. The endoscope 10 includes the insertion section 11 which is to be inserted in a body cavity. The insertion section 11 is formed as a flexible tube and the proximal end of the insertion section 11 is connected to the manipulation unit 14. The distal end of the insertion section 11 is provided with a bendable portion 12, which can be bent by operation of a manipulation knob 15 provided at the manipulation unit 14. At the tip of the bendable portion 12, an end unit 13 accommodating an objective optical system (not shown) is connected. The forceps channel 16 is formed to extend from an inlet 17 formed on the manipulation unit 14, through the whole length of the insertion section 11, to an outlet 18 formed in the end unit 13. The length of the forceps channel 16, i.e., the distance between the inlet 17 and the outlet 18 is indicated as the FC length L. At the inlet 17 of the forceps channel 16, a forceps tap 19 for preventing air fed inside the human cavity, fluid inside the body, or the like from leaking back through the forceps channel is attached. An enlarged cross-sectional view of the forceps tap 19 is shown in Fig. 6. The tap 19 is formed from, for example, an elastic rubber plate formed with a slit 19a. The slit 19a is closed due to the elasticity of the rubber plate. A treatment accessory will be inserted through the slit 19a, pushing open the rubber forming the slit 19a. When the treatment accessory has been removed, the slit returns to its original shape. It should be noted that some endoscopes are not provided with the tap 19. Fig. 7 shows a treatment accessory 60 according to an embodiment of the invention. In this embodiment, the treatment accessory 60 is a biopsy forceps, which has a shaft 61 formed from closely wound coils having a certain elasticity, and a treatment device 62 (i.e., forceps, in this embodiment) which is provided at the distal end of the shaft 61. The shaft 61 and the treatment device 62 are slidably inserted in the forceps channel 16 of the endoscope 10. An operation unit 63 is provided at the proximal end of the shaft 61 for manipulating (e.g., opening and closing the forceps cups) the treatment device 62 through a wire (not shown) which is inserted through the shaft 61. On the shaft 61, as shown in Fig. 7, at a distance B from the distal end thereof, a slidable ring 65 is fitted. The slidable ring 65, as shown in detail in Fig. 8, is made from rubber or synthetic resin having a certain elasticity, and has a slightly smaller inner diameter than the outer diameter of the shaft 61. Accordingly, the slidable ring 65 is held on the shaft 61 due to the frictional and elastic force generated between the shaft 61 and the slidable ring 65. On the shaft 61, at the distance B from the distal end of the treatment device 62, a mark area 66 is formed. The mark area 66 has, for example, a different color from the other portions of the shaft 61. By sliding the slidable ring 65 and positioning it on the mark area 66, the slidable ring 65 is located at a predetermined position, i.e., the distance B from the distal end of the treatment accessory 60, accurately. The slidable ring 65 can be slid relative to the shaft 61 along the axial direction of the shaft 61. As described above, there exists a frictional force between the slidable ring 65 and the shaft 61. As the treatment accessory 60 is inserted in the forceps channel 16 of the endoscope 10, the slidable ring 65 reaches and contacts the tap 19 which is attached to the inlet 17 of the forceps channel 16. After the slidable ring 65 has reached the tap 19, only the shaft 61 is inserted further. That is, the slidable ring 65 is prevented by the tap 19 from entering the forceps channel 16. In this situation, if the shaft 61 is further pushed forward to enter the forceps channel 16, the shaft 61 slides relative to the slidable ring 65, and enters in the forceps channel 16. Due to the friction between the shaft 61 and the slidable ring 65, the resistance against the inserting force is increased and may be felt by the operator of the treatment accessory 60. The distance B indicated in Fig. 7 is set slightly shorter than the FC length L of the forceps channel 16. preferably, the distance B is from 1 to 20 cm shorter than the FC length L. Accordingly, as shown in Fig. 9, when the slidable ring 65 has reached the tap 19, the treatment device 62 provided at the tip of the treatment accessory 60 is located at a position which is length C (C = L - B) away from the outlet 18 of the forceps channel 16. When the treatment accessory 60 is inserted in the forceps channel 16, if the operator feels increased resistance, the insertion can be stopped immediately. At this stage, the distal end of the treatment accessory 60 is still located inside the forceps channel 16. Thereafter, by inserting the treatment accessory 60 slowly, the distal end of the treatment accessory 60 can be extended by an appropriate amount. Fig. 10 shows a treatment accessory 60A according to a second embodiment of the invention. The treatment accessory 60A is similar to the treatment accessory 61 shown in Fig. 9 except for the initial position of the slidable ring 65. In the treatment accessory 60A, the slidable ring 65 is initially located at a distance D from the distal end thereof, the distance D is a sum of the FC length L of the forceps channel 16, and an extending amount E of the treatment device 62 with respect to the outlet 18 of the forceps channel 16. According to the arrangement of the treatment accessory 60A, when the operator feels increased resistance as the treatment accessory 60A is inserted, the operator knows that the distal end of the treatment accessory 60A is located at an appropriate position in which the treatment device 62 extends from the distal end of the forceps channel 16 by the extending amount E as shown in Fig. 10. This arrangement is particularly applicable to keeping an appropriate distance to the affected part or to measure a distance or size of the affected part. Furthermore, since the slidable ring 65 can be located at any position on the shaft 61, even if the length of the insertion section 11 includes manufacturing errors, by fine adjustment of the initial position of the slidable ring 65, the manufacturing error can be compensated. Fig. 11 shows a treatment accessory 60B according to a third embodiment of the invention. The treatment accessory 60B can be used similar to either of the above two embodiments, i.e., similar to the treatment accessory 60 or to the treatment accessory 60A. Specifically, in the treatment accessory 60B, a mark area 66A is formed such that there is a distance B between one end of the mark area 66A and the distal end of the treatment device 62 (cf. Fig. 9), and a distance D between the other end of the mark area 66A and the distal end of the treatment device 62 (cf. Fig. 10). Alternatively, it is also possible to provide two slidable rings on a shaft similar to the shaft 61 of the treatment accessory 60B. With use of such a treatment accessory, when the first slidable ring, positioned to be a distance B from the distal end of the treatment device 62, reaches the inlet 17 of the endoscope 10, the operator detects that the treatment device 62 is approaching the outlet 18 of the forceps channel 16. By further inserting the shaft 61 in the forceps channel, the first slidable ring moves towards the second slidable ring, located at a distance D from the distal end of the treatment device 62. When the two slidable rings contact, the treatment device 62 is extended from the distal end of the forceps channel by an appropriate extended amount E. The slidable ring 65 described above has a cylindrical shape. However, the shape of the slidable ring is not limited to cylindrical, the slidable ring may be formed to have various shapes. Fig. 12 shows a slidable ring 65A according to a fourth embodiment which has a round convex circumferential surface. Fig. 13 shows a slidable ring 65B according to a fifth embodiment which has a round concave circumferential surface. Fig. 14 shows a slidable ring 65C according to a sixth embodiment. The slidable ring 65C is a cylindrical member provided with a flange portion 65F at the treatment device side thereof. With use of the slidable ring 65C, even if the inlet 17 of the forceps channel 16 is not provided with a tap, and is open as shown in Fig. 15, the flange portion 65F prevents the slidable ring 65C from entering in the forceps channel 16. Fig. 16 shows a ring-like member 65D according to a seventh embodiment. In this embodiment, instead of a closed ring, a slidable member 65D which has a C-shape cross section, along a plane perpendicular to the axis of the shaft 61, is used. The slidable member 65D has elasticity and is formed to squeeze, with an elastic force, the shaft 61. The slidable member 65D may be formed from, for example, hard plastic. Fig. 17 shows a ring-like member 65E and a shaft 61B according to an eighth embodiment of the invention. In Fig. 17, the ring-like member 65E is substantially similar to the slidable ring 65C having a cylindrical portion and a flange portion 65F. The diameter of the flange portion F is greater than the diameter of the inlet 17 of the forceps channel 16. In the eighth embodiment, the shaft 61B is provided with a projected portion 61P instead of a mark area. The projected portion 61P is provided on the shaft closer to the treatment device 62 than the slidable ring 65E. By positioning the slidable ring 65E such that the end surface of the slidable ring 65E (i.e., the flange portion 65F) contacts the projected portion 61P, the slidable ring 65E is accurately positioned. It should be noted that the projected portion 61P has a diameter which is smaller than the inner diameter of the forceps channel 16 so that the shaft 61B can be moved freely inside the forceps channel 16. Fig. 18 shows a ring 65G and a shaft 61C according to a ninth embodiment of the invention. As shown in Fig. 18, the shaft 61C is provided with a narrow part, or a small diameter part 61N instead of a marked area. At the small diameter part 61N, the ring 65G is engaged. Note that the outer diameter of the ring 65G is slightly greater than the outer diameter of the shaft 61C so that the operator can feel the passage of the ring 65G through the slit 19a of the tap 19 (see Fig. 6) provided at the inlet 17 of the forceps channel 16. It should be further noted that the outer diameter of the ring 65G is smaller than the inner diameter of the forceps channel 16 so that the shaft 61C can move freely inside the forceps channel 16. The ring 56G may be formed from hard plastic or metal. Fig. 19 shows a ring 65H and a shaft 61D according to a tenth embodiment. As shown in Fig. 19, the shaft 61D is provided with a first protruded portion 61P and a second protruded portion 61P'. At an area between the first and second protruded portions 61P and 61P', the ring 65H is engaged. The outer diameter of the ring 65H as well as the outer diameter of the protruded portions 61P and 61P' are smaller than the inner diameter of the forceps channel 16. With this structure, when the ring 65H passes through the slit 19a of the tap 19, the operator can feel the resistance or click, and detect the position of the treatment device 62. Fig. 20 shows a treatment accessory 60C according to an eleventh embodiment of the invention. The treatment accessory 60C is provided with first, second, third and fourth mark areas 611, 612, 613 and 614. The mark areas 611, 612, 613 and 614 correspond to the endoscopes 10, 10A, 10B and 10C (shown in Figs. 1 to 4). Specifically, the first mark area 611 corresponds to the endoscope 10; the second mark area 612 corresponds to the endoscope 10C; the third mark area 613 corresponds to the endoscope 10A; and the fourth mark area 614 corresponds to the endoscope 10B. If the treatment accessory 60C is used for the endoscope 10 shown in Fig. 1, the slidable ring 65 is located at the first mark area 611. As the treatment accessory 60c is inserted in the forceps channel 16 of the endoscope 10 as shown in Fig. 21, the slidable ring 65 comes into contact with the inlet 17 of the forceps channel 16, and a resistance against the inserting force increases and is sensed by the operator. At this stage, the treatment device 62 is located at a position which is a distance B from the distal end of the insertion section 11 of the endoscope 10, for example, 1 to 10 cm. Even if the operator moves the treatment accessory 60C quickly, the operator can surely detect that the treatment device has reached a predetermined position inside the forceps channel 16, for example, before the treatment device 62 extends from the forceps channel 16. Thereafter, by further inserting, the operator can locate the treatment device 62 at a position extended from the outlet 18 of the forceps channel 16. Fig. 22 shows the treatment accessory 60C being used in the second endoscope 10A. When the slidable ring 65 (located at the third mark 613) has come into contact with the inlet 17A, the treatment device 42 is located inside the forceps channel 16A at the distance B from the outlet 18A. Thus, the treatment accessory 60C can be quickly inserted in the forceps channel 16A and safely stopped before the treatment device 42 extends from the outlet 18A. Fig. 23 shows the treatment accessory 60C being used in the third endoscope 10B. When the slidable ring 65 (located at the fourth mark 614) has come into contact with the inlet 17B, the operator senses increased resistance, and the treatment device 42 is located inside the forceps channel 16B at the distance B from the outlet 18B. Thus, the treatment accessory 60C can be quickly inserted in the forceps channel 16B and safely stopped before the treatment device 62 extends from the outlet 18B. Similarly to the above, when the treatment accessory 60C is used for the fourth endoscope 10C, the slidable ring 65C is positioned at the second mark 612. When the slidable ring 65 comes into contact with the inlet 17C of the forceps channel 16C and the operator senses increased resistance, the treatment device 62 is located at the distance B from the distal end of the forceps channel 16C. Accordingly, the treatment accessory 60C can be quickly inserted in the forceps channel 16C and safely stopped before the treatment device 62 extends from the outlet 18C. Similar to the embodiments described above, the first through fourth mark areas 611 - 614 are preferably formed to have colors or textures different from the other portions of the shaft 60C. Further, it is possible that the four marks 612 - 614 have different colors or textures from each other such that each mark indicates a type or purpose of the endoscope. In any one of the above alternatives, it is advantageous if the inlet of the endoscope has the same color as the mark corresponding thereto. According to the eleventh embodiment, each of the marks corresponds to a position for locating the slidable ring 65 in order to indicate that the distal end of the treatment accessory has reached a predetermined position inside the forceps channel 16. Therefore, when the operator moves the treatment accessory quickly, he/she can stop inserting before the distal end of the treatment accessory extends from the distal end of the forceps channel whichever endoscope 10, 10A, 10B or 10C is used. Further, since the distance between the distal end of the forceps channel and the position where the treatment device is located when the slidable ring 65 has come into contact with the inlet 17 of the forceps channel 16 is relatively short, by further inserting the treatment accessory by a relatively small amount, e.g., by small pushes, the treatment device can be extended from the distal end of the forceps channel and may be located at an appropriate position. Therefore, the treatment accessory 60C can be used for various endoscopes and, in each endoscope, the treatment accessory 60C can be positioned quickly without a risk of damaging the tissue in a human cavity. It should be noted that, in the present embodiment, four mark areas 611 - 614 are provided on the shaft. The number of the marks, however, is not limited to four, and could be any number greater than one. In other words, the number and positions of the mark areas should be determined in accordance with the number of types of endoscopes for which the treatment accessory is to be used.

Claims: A treatment accessory (60) for an endoscope, for being inserted in or removed from a forceps channel (16) of said endoscope (10) through an inlet (17) of said forceps channel (16), comprising: a treatment device (62), a flexible shaft (61), said treatment device (62) being provided at a first end of said flexible shaft (61), said flexible shaft (61) being provided with a marking (65) at a predetermined portion thereof, said treatment device (62) being located at a predetermined position inside said forceps channel (16) when a predetermined portion of said marking (65) is located at said inlet (17) of said forceps channel (16), characterized in that said marking (65) comprises a ring-like member slidably fitted on said flexible shaft (61), a predetermined frictional force being generated between said ring-like member (65) and said flexible shaft (61) when said ring-like member (65) is slid on said flexible shaft (61). The treatment accessory (60) according to claim 1, wherein at least a part of an outer diameter of said ring-like member (65) is greater than an inner diameter of said forceps channel (16). The treatment accessory according to claim 1 or 2, wherein an outer diameter of said ring-like member (65G) is smaller than an inner diameter of said forceps channel (16). The treatment accessory (60) according to claim 1, 2 or 3, wherein said flexible shaft (61) is provided with at least one position indicating area (66), said at least one position indicating area (66) is formed at a portion where said ring-like member (65) is to be initially located. The treatment accessory (60) according to claim 4, wherein said position indicating area (66) is different from the other portion of said flexible shaft (61) by at least one of a color, thickness, texture, and a shape. The treatment accessory (60C) according to claim 4 or 5, wherein said flexible shaft (61E) is provided with a plurality of position indicating areas (611 to 614), corresponding to a plurality of forceps channels having different lengths. The treatment (60C) accessory according to claim 6, wherein said plurality of position indicating areas (611 to 614) are different from each other by at least one of a color, texture, thickness, and a shape. The treatment accessory (60) according to any one of the foregoing claims, wherein said ring like member (65) is formed from elastic material, the inner diameter of said ring like member (65) being smaller than the outer diameter of said shaft (61). The treatment accessory (60) according to any one of the foregoing claims, wherein said shaft (61 ) is provided with a marking (66) which indicates a position where said ring like member (65) is to be initially located. The treatment accessory (60) according any one of the foregoing claims, wherein said ring like member (65) has a cylindrical shape. The treatment accessory according to claim 10, wherein said ring like member (65E) is further provided with a flange (65F) portion which has a greater diameter than the inner diameter of the inlet (17) of said forceps channel (16). The treatment accessory according to claim 10, wherein said ring like member (65A) is formed to have substantially a cylindrical shape, the diameter of an end portion of said cylindrical shape being smaller than the diameter of a central portion of said cylindrical shape. The treatment accessory (60) according to any one of the foregoing claims, wherein said shaft (61) comprises a wound coil pipe. The treatment accessory (60) according to any one of the foregoing claims, wherein said shaft (61) is a flexible resin member.

Inventors: OUCHI TERUO, OUCHI, TERUO, Ouchi, Teruo, c/o Asahi Kogaku Kogyo K.K.
Applicants: ASAHI OPTICAL CO LTD, ASAHI KOGAKU KOGYO KABUSHIKI KAISHA
Application year: 1997
Main classification: A61B10
IPC codes: A61B19, A61B17, A61B18, A61B10