Advance and retreat assist tool for endoscopic treatment instrument

An advance and retreat assist tool includes a base unit, an attachment portion which attaches the base unit to a treatment instrument insertion portion so that the base unit is rotatable around a central axis of a treatment instrument insertion hole portion, and a first tubular member. The advance and retreat assist tool further includes a rotary portion and an advance and retreat mechanism.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an advance and retreat assist tool for an endoscopic treatment instrument.

2. Description of the Related Art

BRIEF SUMMARY OF THE INVENTION

An aspect of advance and retreat assist tool for an endoscopic treatment instrument of the present is the advance and retreat assist tool includes: base unit comprising a hole portion which has a first central axis and a second central axis slanted relative to the first central axis; an attachment portion which attaches the base unit to a treatment instrument insertion portion provided in a grasping portion of an endoscope so that the side of the hole portion having the first central axis faces a treatment instrument insertion hole portion and so that the base unit is rotatable around the central axis of the treatment instrument insertion hole portion; a first tubular member provided to have an axis along the direction of the second central axis, the endoscopic treatment instrument being inserted into and fixed to the first tubular member; a rotary portion into which the first tubular member is inserted and which rotates around the same axis as the first tubular member; and an advance and retreat mechanism which converts a rotation force during the rotation of the rotary portion to an advance and retreat force along the axial direction of the first tubular member to advance and retreat the first tubular member.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

Configuration

The first embodiment is described with reference toFIG. 1A,FIG. 1B,FIG. 1C,FIG. 2A,FIG. 2B,FIG. 2C,FIG. 3A,FIG. 3B,FIG. 3C,FIG. 4A,FIG. 4B,FIG. 5A,FIG. 5B, andFIG. 5C. As an attachment portion400and a treatment instrument insertion cap36are shown inFIG. 1Ain a simplified form, some components are not shown for clarity in some of the drawings.

As shown inFIG. 1A,FIG. 3A, andFIG. 4A, the advance of a first tubular member500means that the first tubular member500moves along the direction of a third central axis500aso that the first tubular member500is inserted into a second tubular member803.

As shown inFIG. 1B,FIG. 3B, andFIG. 4B, the retreat of the first tubular member500means that the first tubular member500moves along the direction of the third central axis500aso that the first tubular member500is removed from the second tubular member803.

As shown inFIG. 1A,FIG. 1B,FIG. 3A,FIG. 3B,FIG. 4A, andFIG. 4B, for example, the advance and retreat of the first tubular member500include the advance of the first tubular member500and the retreat of the first tubular member500.

As shown inFIG. 1A,FIG. 3A, andFIG. 4A, for example, the advance of a treatment instrument51means that the treatment instrument51moves so that the treatment instrument51moves to the side of a distal hard portion21from the side of an operation portion30and a distal end portion51aof the treatment instrument51projects outward from the inside of an insertion portion20via a distal opening portion35bin response to the advance of the first tubular member500.

As shown inFIG. 1B,FIG. 3B, andFIG. 4B, for example, the retreat of the treatment instrument51means that the treatment instrument51moves so that the treatment instrument51moves to the side of the operation portion30from the side of the distal hard portion21and the distal end portion51aof the treatment instrument51is housed in the insertion portion20from the outside via the distal opening portion35bin response to the retreat of the first tubular member500.

As shown inFIG. 1A,FIG. 1B,FIG. 3A,FIG. 3B,FIG. 4A, andFIG. 4B, for example, the advance and retreat of the treatment instrument51include the advance of the treatment instrument51and the retreat of the treatment instrument51.

As shown inFIG. 1AandFIG. 1B, an endoscopic system5has an endoscope10, the endoscopic treatment instrument (hereinafter, treatment instrument51), and an advance and retreat assist tool100for the treatment instrument51.

The endoscope10has a hollow and elongated insertion portion20to be inserted into, for example, a body cavity, and the operation portion30which is coupled to the proximal end portion of the insertion portion20and which operates the endoscope10.

The insertion portion20has the distal hard portion21, a bending portion23, and a flexible tubular portion25from the distal end portion side of the insertion portion20to the proximal end portion side portion of the insertion portion20. The proximal end portion of the distal hard portion21is coupled to the distal end portion of the bending portion23, and the proximal end portion of the bending portion23is coupled to the distal end portion of the flexible tubular portion25.

The distal hard portion21is the distal end portion of the insertion portion20, and is hard and unbendable. The distal hard portion21has the distal opening portion35b, and an unshown observation window included in an unshown observation optical system. The distal hard portion21also has an unshown pair of illumination windows which are provided across the observation window and which are included in an unshown illumination optical system, and a nozzle which supplies air and water to the observation window. The distal opening portion35b, the observation window, the illumination windows, and the nozzle are provided in a distal end face of the distal hard portion21.

The bending portion23is bent in a desired direction, for example, in an upward, downward, leftward, or rightward direction by the operation of a later-described bending operation portion37. When the bending portion23is bent, the position and direction of the distal hard portion21are changed. An observation target is illuminated by unshown illumination light, and the observation target enters into an observation field. This observation target is, for example, an affected part or a lesion in a subject (e.g., body cavity).

The flexible tubular portion25has desired flexibility. Therefore, the flexible tubular portion25is bent by an external force. The flexible tubular portion25is a tubular member extending from a later-described body portion31in the operation portion30.

The operation portion30has the body portion31from which the flexible tubular portion25extends, a grasping portion33which is coupled to the proximal end portion of the body portion31and which is grasped by a surgeon who operates the endoscope10, and a universal cord41connected to the grasping portion33.

The grasping portion33has a treatment instrument insertion portion35, the bending operation portion37which is operated to bend the bending portion23, and a switch portion39. The treatment instrument insertion portion35is provided on the distal end portion side of the grasping portion33. The bending operation portion37and the switch portion39are provided on the proximal end portion side of the grasping portion33. As shown inFIG. 5A, the grasping portion33is grasped by the left hand of the surgeon, and the bending operation portion37and the switch portion39are operated by the fingers of the left hand.

The treatment instrument insertion portion35branches off from the grasping portion33. Thus, as shown inFIG. 1AandFIG. 1B, the central axis direction of the treatment instrument insertion portion35is slanted relative to the direction of a central axis33aof the grasping portion33.

As shown inFIG. 1AandFIG. 1B, the treatment instrument insertion portion35has a treatment instrument insertion hole portion35awhich is provided at the end portion of the treatment instrument insertion portion35and which is used to insert the treatment instrument51into the endoscope10.

The treatment instrument insertion hole portion35ais coupled to the proximal end portion of an unshown treatment instrument insertion channel. The treatment instrument insertion channel is provided inside the insertion portion20, and provided from the flexible tubular portion25to the distal hard portion21via the bending portion23. The distal end portion of the treatment instrument insertion channel is in communication with the distal opening portion35bprovided in the distal hard portion21. The treatment instrument insertion hole portion35ais an insertion hole portion used to insert the treatment instrument51into the treatment instrument insertion channel.

As shown inFIG. 1AandFIG. 1B, a central axis35cof the treatment instrument insertion hole portion35ais provided coaxially with the central axis of the treatment instrument insertion portion35, and is thus slanted relative to the central axis33aof the grasping portion33. The direction of the central axis35cis slanted relative to the direction of the central axis33aof the grasping portion33.

As shown inFIG. 1A,FIG. 1B,FIG. 2A,FIG. 2B,FIG. 2C,FIG. 4A,FIG. 4B,FIG. 5A,FIG. 5B, andFIG. 5C, the treatment instrument insertion portion35further has a cylindrical treatment instrument insertion cap36to be inserted into the treatment instrument insertion hole portion35a. The treatment instrument insertion cap36is made of, for example, a metal. The central axis of the treatment instrument insertion cap36is provided coaxially with the central axis35cof the treatment instrument insertion hole portion35a. Thus, the treatment instrument insertion cap36is slanted relative to the grasping portion33. When the cylindrical treatment instrument insertion cap36is inserted in the treatment instrument insertion hole portion35a, the treatment instrument insertion cap36is in communication with the treatment instrument insertion channel.

The treatment instrument51is inserted into the treatment instrument insertion channel from the treatment instrument insertion hole portion35avia the treatment instrument insertion cap36, and pressed to the side of the distal hard portion21. As shown inFIG. 1AandFIG. 1B, the treatment instrument51is then projected from the distal opening portion35b.

As shown inFIG. 1A,FIG. 1B,FIG. 2A,FIG. 2B,FIG. 2C,FIG. 4A,FIG. 4B,FIG. 5A,FIG. 5B, andFIG. 5C, the advance and retreat assist tool100is attached to the treatment instrument insertion cap36. In this case, the treatment instrument insertion cap36is brought into communication with a first hole portion311of a later-described base member310.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the treatment instrument insertion cap36has a distal end portion to be inserted into the treatment instrument insertion hole portion35a, and a proximal end portion which projects outward from the treatment instrument insertion hole portion35aand which is exposed to the outside. The proximal end portion has an edge portion36c. The edge portion36cis formed as an outer flange, and is folded outward in the diametrical direction of the treatment instrument insertion cap36.

The bending operation portion37has a horizontal bending operation knob37awhich is operated to horizontally bend the bending portion23, a vertical bending operation knob37bwhich is operated to vertically bend the bending portion23, and a fixing knob37cwhich fixes the position of the bent bending portion23.

The switch portion39is operated by the hand of the surgeon when the grasping portion33is grasped by the surgeon. The switch portion39is operated during the operation of various functions of the endoscope such as air supply, water supply, suction, and photography.

The universal cord41has an unshown connector which can be attached to and removed from an unshown control apparatus.

The treatment instrument51is formed by, for example, an elongated linear member.

[Advance and Retreat Assist Tool100]

As shown inFIG. 1AandFIG. 1B, the advance and retreat assist tool100is removably attached to the endoscope10, in particular, the treatment instrument insertion portion35. More specifically, as shown inFIG. 1C,FIG. 5BandFIG. 5C, the advance and retreat assist tool100is removably attached to the treatment instrument insertion cap36which is inserted into the treatment instrument insertion hole portion35aof the treatment instrument insertion portion35so that the advance and retreat assist tool100is rotatable around the central axis of the treatment instrument insertion cap36(the central axis35cof the treatment instrument insertion hole portion35a). The advance and retreat assist tool100assists the treatment instrument51in advancing and retreating along the longitudinal axis direction of the treatment instrument51. The treatment instrument51is inserted in the endoscope10from the treatment instrument insertion hole portion35avia the treatment instrument insertion cap36. The distal end portion51aof the treatment instrument51can project from the distal opening portion35b.

As shown inFIG. 1AFIG. 1B,FIG. 1C,FIG. 5A,FIG. 5B, andFIG. 5C, the advance and retreat assist tool100has a base unit300, and the attachment portion400which removably attaches the base unit300to the treatment instrument insertion portion35(the treatment instrument insertion cap36) so that the base unit300is rotatable around the central axis35cof the treatment instrument insertion hole portion35a(the treatment instrument insertion cap36). As shown inFIG. 1AFIG. 1B,FIG. 5A,FIG. 5B, andFIG. 5C, the advance and retreat assist tool100further has the first tubular member500through which the treatment instrument51is inserted and which guides the treatment instrument51to the endoscope10via the base unit300, and a fixing portion600which fixes the treatment instrument51to the first tubular member500. As shown inFIG. 1A,FIG. 1B,FIG. 2A,FIG. 2B,FIG. 3A,FIG. 3B,FIG. 3C,FIG. 4A,FIG. 4B,FIG. 5A,FIG. 5B, andFIG. 5C, the advance and retreat assist tool100further has a rotary portion700provided in the first tubular member500, and an advance and retreat mechanism800which advances and retreats the first tubular member500by a rotation force of the rotary portion700. The advance and retreat assist tool100further has a regulating mechanism900which regulates the advance and retreat of the first tubular member500, and a support unit950which supports the first tubular member500so that the first tubular member500advances and retreats.

As shown inFIG. 1A,FIG. 1B,FIG. 2A,FIG. 2B,FIG. 2C,FIG. 3A,FIG. 3B,FIG. 4A,FIG. 4B,FIG. 5A,FIG. 5B, andFIG. 5C, the base unit300is removably attached to the treatment instrument insertion cap36by the attachment portion400. The base unit300is also attached to the treatment instrument insertion cap36by the attachment portion400rotatably relative to the treatment instrument insertion cap36around the central axis of the treatment instrument insertion cap36. As shown inFIG. 2AandFIG. 2B, the base unit300has the base member310.

As shown inFIG. 1AandFIG. 1B, the base member310is provided to face the treatment instrument insertion hole portion35ain the direction of the central axis35cof the treatment instrument insertion hole portion35awhen the advance and retreat assist tool100is attached to the endoscope10.

As shown inFIG. 4AandFIG. 4B, the base member310has the first hole portion311which has a first central axis311a, and a second hole portion313which has a second central axis313aslanted relative to the first central axis311aand which is in communication with the first hole portion311.

The first hole portion311faces the inside of the treatment instrument insertion cap36and the treatment instrument insertion channel when the advance and retreat assist tool100is attached to the endoscope10. At the same time, as shown inFIG. 1A,FIG. 1B, andFIG. 1C, the first central axis311aof the first hole portion311is provided coaxially with the central axis35cof the treatment instrument insertion hole portion35a, and is slanted relative to the central axis33aof the grasping portion33. As shown inFIG. 1C, the second central axis313aof the second hole portion313is slanted relative to the central axis35cof the treatment instrument insertion hole portion35a.

The first hole portion311is in communication with the outside in one end face of the base member310, and the second hole portion313is in communication with the outside in the other end face of the base member310. The first hole portion311is depressed in one end face of the base member310. The second hole portion313is depressed in the other end face of the base member310.

As shown inFIG. 4AandFIG. 4B, the first hole portion311and the second hole portion313function as guide hole portions which guide, to the treatment instrument insertion hole portion35avia the attachment portion400and the treatment instrument insertion cap36, the treatment instrument51which is inserted through the first tubular member500. The first hole portion311has substantially the same diameter as that of the treatment instrument51. The second hole portion313also functions as an insertion hole portion into which the first tubular member500is inserted. The second hole portion313is larger than the first hole portion311.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the base member310further has a third hole portion315which is in communication with the first hole portion311and which is larger than the first hole portion311. The central axis of the third hole portion315is provided coaxially with the first central axis311aof the first hole portion311. The third hole portion315is in communication with the outside in one end face of the base member310, and is depressed in one end face of the base member310. The third hole portion315is provided outside the first hole portion311, in particular, provided on the side of the treatment instrument insertion cap36. Thus, one end portion of the first hole portion311is in communication with the second hole portion313, and the other end portion of the first hole portion311is in communication with the third hole portion315. A support portion430of the attachment portion400is screwed into the third hole portion315.

As shown inFIG. 1A,FIG. 1B,FIG. 1C,FIG. 4A,FIG. 4B,FIG. 5A,FIG. 5B, andFIG. 5C, the attachment portion400removably attaches the base unit300to the treatment instrument insertion portion35(the treatment instrument insertion cap36) so that the first central axis311ais provided coaxially with the central axis35cof the treatment instrument insertion hole portion35a, so that the first hole portion311faces the treatment instrument insertion hole portion35a, and so that the base member310of the base unit300is rotatable around the central axis35cof the treatment instrument insertion hole portion35a(the central axis of the treatment instrument insertion cap36).

As shown inFIG. 2A,FIG. 2B,FIG. 2C,FIG. 4A,FIG. 4B,FIG. 5B, andFIG. 5C, the attachment portion400has a cylindrical body portion410which is removably attached to the treatment instrument insertion cap36so that the body portion410is rotatable around the central axis35cof the treatment instrument insertion hole portion35a, and the cylindrical support portion430which is removably attached to the body portion410and which supports the base member310. The body portion410is independent of the support portion430. The body portion410and the support portion430are comprised of an elastic material such as a resin or rubber.

[Attachment of Body Portion410and Support Portion430]

As shown inFIG. 4AandFIG. 4B, the body portion410has a body thread groove portion411formed in the inner circumferential surface of the body portion410. The body thread groove portion411is provided at the proximal end portion of the body portion410.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the support portion430has a distal end support thread groove portion431which is formed in the outer circumferential surface of the support portion430and which meshes with the body thread groove portion411. The distal end support thread groove portion431is provided at the distal end portion of the support portion430.

The support portion430is attached to the body portion410when the support portion430is screwed into the body portion410in the central axis direction of the attachment portion400as shown inFIG. 2Cso that the body thread groove portion411and the distal end support thread groove portion431mesh with each other while the body portion410is attached to the treatment instrument insertion cap36. Thus, the body portion410and the support portion430fasten to each other. At the same time, the body portion410and the support portion430communicate with the treatment instrument insertion cap36.

As shown inFIG. 4A, andFIG. 4B, when the support portion430is attached to the body portion410, the edge portion36cof the treatment instrument insertion cap36which is formed as the outer flange is provided between the support portion430and a distal end portion of the body portion410formed as an inner flange in the direction of the central axis35cof the treatment instrument insertion hole portion35a. The support portion430is attached to the body portion410so that the support portion430presses the edge portion36cinto the distal end portion of the body portion410. Thus, the attachment portion400is fixed to the treatment instrument insertion cap36.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the advance and retreat assist tool100further has an interference prevention member450which intervenes between the support portion430and the edge portion36cof the treatment instrument insertion cap36in the direction of the central axis35cof the treatment instrument insertion hole portion35aand which prevents interference between the support portion430and the edge portion36c. The interference prevention member450is made of, for example, PTFE. The interference prevention member450is in close contact with the support portion430and the edge portion36cof the treatment instrument insertion cap36.

As shown inFIG. 2A,FIG. 2B, andFIG. 2C, the body portion410has a cutout portion413which is formed by the depression of a part of the edge portion of the body portion410in the central axis direction of the body portion410. The cutout portion413is provided at the distal end portion of the body portion410. The cutout portion413is not provided flush with the body thread groove portion411, and is provided closer to the side of the treatment instrument insertion hole portion35athan the body thread groove portion411. The cutout portion413is not formed over the entire circumference of the body portion410in the circumferential direction of the body portion410, but is formed in a size smaller than, for example, a semicircle. This cutout portion413is in communication with the inside of body portion410in the diametrical direction of the body portion410.

As described above, the distal end portion of the body portion410is folded inward as the inner flange.

[Attachment of Body Portion410to Treatment Instrument Insertion Cap36]

The body portion410is not attached to the treatment instrument insertion cap36by being fitted into the proximal end portion of the treatment instrument insertion cap36in the axial direction of the treatment instrument insertion cap36. As shown inFIG. 2C, the cutout portion413functions as a head, and the body portion410is pressed into the proximal end portion of the treatment instrument insertion cap36from the cutout portion413in the diametrical direction of the body portion410. That is, the body portion410is pressed into the proximal end portion of the treatment instrument insertion cap36from the side surface of the treatment instrument insertion portion35via the cutout portion413in the diametrical direction of the body portion410, and is thereby fitted into the proximal end portion of the treatment instrument insertion cap36, and attached to the proximal end portion of the treatment instrument insertion cap36. In other words, the proximal end portion of the treatment instrument insertion cap36is fitted into the body portion410in the diametrical direction of the body portion410via the cutout portion413. Thus, the body portion410is attached to the proximal end portion of the treatment instrument insertion cap36, and the proximal end portion of the treatment instrument insertion cap36is provided inside the body portion410. In this instance, as shown in FIG.4A, andFIG. 4B, the distal end portion of the body portion410formed as the inner flange is caught on the edge portion36cof the treatment instrument insertion cap36formed as the outer flange. In this state, as shown inFIG. 5B, andFIG. 5C, the body portion410is rotatable relative to the treatment instrument insertion cap36around the central axis35cof the treatment instrument insertion hole portion35a.

When the body portion410is detached from the treatment instrument insertion cap36, the body portion410is pulled relative to the proximal end portion of the treatment instrument insertion cap36in the diametrical direction of the body portion410via the cutout portion413and then detached from the proximal end portion of the treatment instrument insertion cap36, in reverse order from the above.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, in the support portion430which supports the base member310of the base unit300, the support portion430is attached to the body portion410so that the first central axis311aof the first hole portion311is provided coaxially with the central axis35cof the treatment instrument insertion hole portion35aand so that the first hole portion311faces the treatment instrument insertion hole portion35a.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the support portion430has a distal end portion which is screwed into the body portion410, and a proximal end portion which is screwed into the third hole portion315and thereby supports the base member310. The proximal end is screwed into the third hole portion315so that the support portion430communicates with the first hole portion311.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the support portion430has a watertight member433which is provided inside the proximal end portion of the support portion430and which keeps the base member310and the support portion430watertight. The watertight member433has, for example, a ring-shaped packing.

As shown inFIG. 2BandFIG. 2C, the watertight member433has a protrusion portion433aprovided in the outer circumferential surface of the watertight member433. The protrusion portion433aslides on a slide groove435formed in the proximal end portion of the support portion430when the watertight member433is inserted into and removed from the proximal end portion of the support portion430. The protrusion portion433ais grasped when the watertight member433is inserted into and removed from the proximal end portion of the support portion430, and is provided to position the watertight member433in the circumferential direction of the support portion430.

[Attachment of Support Portion430to Base Member310]

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the base member310further has a base thread groove portion315aformed in the inner circumferential surface of the third hole portion315.

As shown inFIG. 2B,FIG. 2C,FIG. 4A, andFIG. 4B, the support portion430further has a proximal support thread groove portion437which is formed in the outer circumferential surface of the support portion430and which meshes with the base thread groove portion315a. The proximal support thread groove portion437is provided at the proximal end portion of the support portion430.

The support portion430is screwed into the third hole portion315in the central axis direction of the attachment portion400as shown inFIG. 2C,FIG. 4A, andFIG. 4Bso that the base thread groove portion315aand the proximal support thread groove portion437mesh with each other, and the support portion430is thereby attached to the base member310. Thus, the base member310and the support portion430fasten to each other. At the same time, the support portion430communicates with the first hole portion311.

As described above, the base member310is attached to the support portion430, the support portion430is attached to the body portion410, and the body portion410is attached to the treatment instrument insertion cap36.

In this state, as shown inFIG. 1C, the central axis direction of the treatment instrument insertion portion35is slanted relative to the direction of the central axis33aof the grasping portion33.

As shown inFIG. 1C,FIG. 5B, andFIG. 5C, an angle formed between the direction of the central axis35cof the treatment instrument insertion hole portion35a(the direction of the first central axis311aof the first hole portion311) and the direction of the central axis33aof the grasping portion33is an angle θ1. The angle θ1 is invariable even if the advance and retreat assist tool100including the attachment portion400rotates around the central axis of the treatment instrument insertion cap36.

As shown inFIG. 10andFIG. 5B, an angle formed between the direction of the second central axis313aand the direction of the central axis33aof the grasping portion33is an angle θ2. The angle θ2 is an angle at which the advance and retreat assist tool100is slanted closer to the grasping portion33, a clearance60between the grasping portion33and the rotary portion700is smallest, the distance between the grasping portion33and the rotary portion700is shortest, and the rotary portion700is adjacent to the grasping portion33. Thus, the angle θ2 is an angle which is formed when the rotary portion700is operated to advance and retreat the treatment instrument51and which allows one hand to grasp the endoscope10and advance and retreat the treatment instrument51at the same time.

As shown inFIG. 10andFIG. 5C, an angle formed between the direction of the second central axis313aand the direction of the central axis33aof the grasping portion33is an angle θ3. The angle θ3 is an angle at which the advance and retreat assist tool100is slanted away from the grasping portion33, the clearance60between the grasping portion33and the rotary portion700is widest, and the distance between the grasping portion33and the rotary portion700is longest. Thus, the angle θ3 is an angle which is formed when the treatment instrument51does not need to be operated to advance and retreat and when the rotary portion700is not operated and which eliminates the interruption of the grasping by the advance and retreat assist tool100.

As shown inFIG. 1C,FIG. 5B, andFIG. 5C, the attachment portion400attached to the treatment instrument insertion cap36rotates around the central axis35cof the treatment instrument insertion hole portion35aso that the angle θ1>the angle θ2 when the rotary portion700is operated and so that the angle θ3>the angle θ1 when the rotary portion700is not operated. As a result, the base member310attached to the attachment portion400also rotates.

As shown inFIG. 4AandFIG. 4B, the first tubular member500has the third central axis500a. The first tubular member500is provided so that the third central axis500ais provided along the direction of the second central axis313aand so that the third central axis500ais provided coaxially with the second central axis313a. The first tubular member500is formed as a cylindrical member into which the treatment instrument51is inserted. The treatment instrument51is inserted into the first tubular member500from a proximal end portion500cof the first tubular member500, and is projected from a distal end portion500bof the first tubular member500.

As shown inFIG. 4A, the treatment instrument51is directly inserted into the first hole portion311when the first tubular member500advances. As shown inFIG. 4B, the treatment instrument51is inserted into the first hole portion311via the second hole portion313when the first tubular member500retreats. That is, the first tubular member500functions as a guide member which guides the treatment instrument51to the first hole portion311.

As shown inFIG. 2B,FIG. 4A, andFIG. 4B, the first tubular member500has the above-mentioned third central axis500a, and the distal end portion500bwhich is inserted into the second hole portion313when the first tubular member500advances and which is removed from the second hole portion313when the first tubular member500retreats. The first tubular member500also has the proximal end portion500cto which a proximal end portion51bof the treatment instrument51is fixed by the fixing portion600. The first tubular member500further has an opening portion500dwhich is provided in the circumferential surface of the first tubular member500and with which a later-described protrusion portion801is engaged.

As shown inFIG. 4A, the distal end portion500bis inserted into the second hole portion313so that the first tubular member500is in communication with the first hole portion311when the first tubular member500advances. As shown inFIG. 4B, the distal end portion500bis removed from the second hole portion313so that the first tubular member500faces the first hole portion311when the first tubular member500retreats.

As shown inFIG. 4A, the opening portion500dis provided on the side of the distal end portion500bso that the opening portion500dis not inserted into the second hole portion313when the distal end portion500bis inserted into the second hole portion313. The opening portion500dis always exposed from the second hole portion313. The opening portion500dis, for example, circular. The opening portion500dis a through-hole portion which passes through the first tubular member500in the thickness direction of the first tubular member500. A pair of opening portions500dare provided with respect to the third central axis500a.

As shown inFIG. 2B,FIG. 3A,FIG. 3B,FIG. 4A, andFIG. 4B, the fixing portion600is provided at the proximal end portion500cof the first tubular member500. The fixing portion600fixes the proximal end portion51bof the treatment instrument51to the proximal end portion500cof the first tubular member500. The fixing portion600has a cylindrical portion601through which the treatment instrument51is inserted and which is inserted into the proximal end portion500cof the first tubular member500, and a fixing member605which is mounted at the end portion of the cylindrical portion601and through which the treatment instrument51is inserted. The fixing portion600also has a fastening portion603which functions as a cap to cover the cylindrical portion601and the fixing member605and which fastens the cylindrical portion601.

The fastening portion603rotates around the axis of the fastening portion603and thereby fastens the cylindrical portion601, and compresses the fixing member605by fastening. The fixing member605comes into close contact with the proximal end portion51bof the treatment instrument51by compression. As a result, the treatment instrument51becomes integral with the first tubular member500via the fixing portion600. The fixing member605is formed by, for example, elastic rubber.

As shown inFIG. 1AandFIG. 1B, the rotary portion700rotates around the third central axis500a. The rotary portion700is formed as a cylindrical member into which the first tubular member500is inserted. More specifically, the first tubular member500is inserted into the rotary portion700so that the central axis of the rotary portion700is provided coaxially with the third central axis500a. As shown inFIG. 4A, the rotary portion700is rotatable around the second central axis500ausing the first tubular member500as a central axis while the first tubular member500is inserted in the rotary portion700. As shown inFIG. 4A, the rotary portion700has a length such that the proximal end portion500cof the first tubular member500projects outside the proximal end portion of the rotary portion700along the direction of the third central axis500awhen the distal end portion500bof the first tubular member500is inserted in the second hole portion313while the first tubular member500is inserted in the rotary portion700. As shown inFIG. 1AandFIG. 1B, the rotary portion700is provided adjacent to the grasping portion33when the advance and retreat assist tool100is attached to the endoscope10. Thus, the rotary portion700functions as an operation knob.

As shown inFIG. 1AandFIG. 1B, the rotary portion700has recess portions701provided in the outer circumferential surface of the rotary portion700. The recess portions701are provided along the direction of the third central axis500a. The recess portions701are adjacent to each other in a direction around the third central axis500a. The inner circumferential surface of the recess701is, for example, smoothly semicircular. As shown inFIG. 5, the recess portions701are formed as mounting surfaces to mount the fingers of the left hand grasping the grasping portion33.

[Configuration of Advance and Retreat Mechanism800]

The advance and retreat mechanism800intervenes between the rotary portion700and the first tubular member500, the advance and retreat mechanism800converts the rotation force of the rotary portion700to an advance and retreat force of the first tubular member500, and the advance and retreat mechanism800transmits the advance and retreat force to the first tubular member500and thereby advances and retreats the first tubular member500along the direction of the third central axis500a, when the rotary portion700rotates.

As shown inFIG. 2B,FIG. 3A,FIG. 3B,FIG. 4A, andFIG. 4B, the advance and retreat mechanism800has the protrusion portion801, the second tubular member803, and a third tubular member805. As shown inFIG. 4AandFIG. 4B, the protrusion portion801, the second tubular member803, and the third tubular member805intervene between the first tubular member500and the rotary portion700in the diametrical direction of the first tubular member500.

As shown inFIG. 3A,FIG. 3B,FIG. 3C,FIG. 4A, andFIG. 4B, the protrusion portion801is provided straight along the diametrical direction of the first tubular member500so that the protrusion portion801passes through a later-described long opening portion803dand is inserted into a later-described spiral opening portion805d. The protrusion portion801is engaged with the opening portion500d, and is thereby engaged with the circumferential surface of the first tubular member500. As shown inFIG. 3C, the protrusion portion801has a diameter such that the protrusion portion801abuts on the edge portion of the long opening portion803dand the edge portion of the spiral opening portion805d.

As shown inFIG. 2B,FIG. 3A,FIG. 3B,FIG. 4A, andFIG. 4B, the second tubular member803has a fourth central axis803a, and a distal end portion803bwhich is fitted into and thus fixed to the second hole portion313so that the fourth central axis803ais provided along the direction of the second central axis313aand so that the fourth central axis803ais provided coaxially with the second central axis313a. The second tubular member803further has a proximal end portion803c, and the long opening portion803dprovided in the circumferential surface of the second tubular member803along the direction of the fourth central axis803a.

As shown inFIG. 4AandFIG. 4B, the distal end portion803bis formed as a fixed end which is fixed to the base member310by, for example, a screw portion213ewhen the distal end portion803bis inserted in the second hole portion313. The screw portion213eis inserted through the side surface of the base member310, and abuts on the circumferential surface of the distal end portion803b.

As shown inFIG. 4AandFIG. 4B, the proximal end portion803cis formed as a fixed end which is fixed to the support unit950by, for example, a screw portion213fwhen the proximal end portion803cis inserted in the fit hole portion953cof the support unit950. The screw portion213fis inserted through the side surface of the support unit950, and abuts on the circumferential surface of the proximal end portion803c.

As a result, the second tubular member803is prevented from rotating and moving, and is fixed to the base unit300and the support unit950.

As shown inFIG. 2B, the long opening portion803dis provided straight from the side of the distal end portion803bto the side of the proximal end portion803c. As shown inFIG. 4AandFIG. 4B, the distal end portion of the long opening portion803dis provided on the side of the distal end portion803bso that the distal end portion of the long opening portion803dis not inserted into the second hole portion313when the distal end portion803bis inserted in the second hole portion313. As shown inFIG. 4AandFIG. 4B, the proximal end portion of the long opening portion803dis provided on the side of the proximal end portion803cso that the proximal end portion of the long opening portion803dis not inserted into the fit hole portion953cof the support unit950when the proximal end portion803cis inserted in the fit hole portion953cof the support unit950. That is, the long opening portion803dis exposed from the second hole portion313and the fit hole portion953cof the support unit950.

As shown inFIG. 4AandFIG. 4B, the long opening portion803dhas a length slightly greater than the length from one edge portion of the later-described spiral opening portion805dto the other edge portion in the direction of the fourth central axis803a. One edge portion side of the long opening portion803dfaces one edge portion of the spiral opening portion805d, and the other edge portion side of the long opening portion803dfaces the other edge portion of the spiral opening portion805d. The long opening portion803dis substantially equal in length to the rotary portion700.

The length of the long opening portion803dcorresponds to the movement amount of the first tubular member500, and corresponds to the advance and retreat amount of the treatment instrument51. These are substantially equal in size to each other. The maximum value of the length corresponds to the maximum value of the movement amount and the maximum value of the advance and retreat amount. Each of these maximum values corresponds to the size of the part to be treated with the treatment instrument51, and has a desired value. The maximum value is, for example, 30 mm.

The long opening portion803ddoes not pass through the second tubular member803in the direction of the fourth central axis803a. The long opening portion803dpasses through the second tubular member803in the thickness direction of the second tubular member803. A pair of long opening portions803dare provided with respect to the fourth central axis803a.

Such a second tubular member803is formed as a cylindrical member into which the first tubular member500is inserted so that part of the long opening portion803dis in communication with the opening portion500dand the protrusion portion801is inserted through the long opening portion803d. The second tubular member803has a length such that the proximal end portion500cof the first tubular member500projects outside the proximal end portion803cof the second tubular member803along the direction of the second central axis313awhen the first tubular member500is inserted in the second tubular member803, the distal end portion500bof the first tubular member500is inserted in the second hole portion313, and the distal end portion803bof the second tubular member803is fitted in the second hole portion313.

As shown inFIG. 2B, the third tubular member805has a fifth central axis805aprovided coaxially with the third central axis500a, and a distal end portion805b. The third tubular member805also has a proximal end portion805c, and the spiral opening portion805dprovided in the circumferential surface of the third tubular member805to wind around the fifth central axis805a.

As shown inFIG. 4AandFIG. 4B, the third tubular member805is provided so that the distal end portion805bis not inserted into the second hole portion313and the proximal end portion805cis not inserted into the support unit950.

As shown inFIG. 4AandFIG. 4B, the third tubular member805is inserted into the rotary portion700so that the third tubular member805rotates relative to the second tubular member803around the fifth central axis805atogether with the rotary portion700. The third tubular member805is fixed to the rotary portion700by a screw portion213gshown inFIG. 2Bso that the third tubular member805rotates together with the rotary portion700. Thus, the third tubular member805rotates in the same direction as the rotary portion700. As shown inFIG. 3C,FIG. 4A, andFIG. 4B, the third tubular member805functions as a cylindrical member into which the second tubular member803is inserted so that part of the spiral opening portion805dis in communication with part of the long opening portion803dand so that the protrusion portion801inserted through the long opening portion803dis inserted into the spiral opening portion805d. Such a third tubular member805functions as a cam ring. The third tubular member805is substantially equal in length to the long opening portion803dand the rotary portion700.

As shown inFIG. 2B, the spiral opening portion805dis provided from the distal end portion805bto the proximal end portion805cin the direction of the fifth central axis805a. The spiral opening portion805ddoes not pass through the third tubular member805in the direction of the fifth central axis805a. The spiral opening portion805dpasses through the third tubular member805in the thickness direction of the third tubular member805. A pair of spiral opening portions805dare provided with respect to the third central axis500a.

[Operation of Advance and Retreat Mechanism800]

As shown inFIG. 1A,FIG. 1B,FIG. 3A,FIG. 3B,FIG. 3C,FIG. 4A, andFIG. 4B, if the rotary portion700rotates around the third central axis500a, the third tubular member805also rotates simultaneously with the rotary portion700. As a result, the spiral opening portion805dprovided in the third tubular member805also rotates.

As shown inFIG. 3AandFIG. 3B, the protrusion portion801is in abutment with the edge portion of the spiral opening portion805d. Thus, in response to the rotation of the spiral opening portion805d, the protrusion portion801is pressed to rotate by the spiral opening portion805d. As shown inFIG. 3AandFIG. 3B, the protrusion portion801is inserted through the long opening portion803d, and is also in abutment with the edge portion of the long opening portion803d. Thus, the protrusion portion801is pressed to rotate by the spiral opening portion805d, so that the protrusion portion801moves in the long opening portion803dalong the direction of the third central axis500a.

Thus, the third tubular member805rotates together with the rotation of the rotary portion700, so that the spiral opening portion805drotates. As a result of the rotation of the spiral opening portion805d, the protrusion portion801moves in the long opening portion803dalong the direction of the third central axis500aby the spiral opening portion805d.

The protrusion portion801abuts on the edge portion of the long opening portion803d, so that the first tubular member500having the distal end portion500bwith which the protrusion portion801is engaged is prevented from rotating around the third central axis500a.

The spiral opening portion805drotates, and the protrusion portion801moves in the long opening portion803dalong the direction of the third central axis500a, so that the first tubular member500having the distal end portion500bwith which the protrusion portion801is engaged advances and retreats along the direction of the third central axis500awhile the rotation of the first tubular member500around the third central axis500ais prevented. As a result, the treatment instrument51fixed to the first tubular member500advances and retreats.

The distal end portion803bof the second tubular member803is fitted into and thus fixed to the second hole portion313, and the proximal end portion803cof the second tubular member803is fitted into and thus fixed to the fit hole portion953cof the support unit950. Therefore, the second tubular member803remains fixed. This prevents the long opening portion803dfrom rotating in the same manner as the spiral opening portion805d.

The protrusion portion801only moves in the long opening portion803dalong the direction of the third central axis500a. Therefore, the first tubular member500only advances and retreats along the direction of the third central axis500a, and the rotation of the first tubular member500around the third central axis500ais prevented. Similarly, the treatment instrument51only advances and retreats, and the rotation of the treatment instrument51around the third central axis500ais prevented.

Thus, the advance and retreat mechanism800advances and retreats the treatment instrument51while the treatment instrument51is prevented from rotating around the third central axis500ain response to the rotation of the rotary portion700around the third central axis500awhen the rotary portion700rotates around the third central axis500a.

The regulating mechanism900regulates the advance and retreat of the first tubular member500when the first tubular member500advances and retreats along the direction of the third central axis500aso that the distal end portion500bof the first tubular member500moves along the direction of the third central axis500abetween a part where the first hole portion311provided on the distal end portion side of the rotary portion700is in communication with the second hole portion313and a position on the side where the first tubular member500provided on the proximal end portion side of the rotary portion700comes off the rotary portion700.

The regulating mechanism900is formed by the protrusion portion801and by the edge portion of the spiral opening portion805d.

As shown inFIG. 1A,FIG. 1B,FIG. 2A,FIG. 2B,FIG. 3A,FIG. 3B,FIG. 4A, andFIG. 4B, the support unit950supports the first tubular member500via the protrusion portion801, the second tubular member803, and the third tubular member805so that the third central axis500ais provided coaxially with the second central axis313a, the first tubular member500advances and retreats along the direction of the third central axis500a, and thus the first tubular member500is prevented from moving in a direction that intersects at right angles with the direction of the third central axis500a.

The support unit950has a base member951which is provided along the direction of the third central axis500aand which is provided on the side of the rotary portion700, and a base member953which is provided along the direction that intersects at right angles with the direction of the third central axis500aand which is provided above the rotary portion700.

The base member951has one end portion fixed to the base member310by, for example, a screw portion213h, and the other end portion fixed to the base member953by, for example, a screw portion213i.

The base member953has the fit hole portion953cinto which the proximal end portion803cof the second tubular member803is fitted. The base member953is fixed, by, for example, the screw portion213f, to the proximal end portion803cof the second tubular member803which is fitted into the fit hole portion953c.

The support unit950supports the first tubular member500via the base member310and the second tubular member803. The support unit950supports the third tubular member805via the base member310, the second tubular member803, and a washer955.

[Attachment of Advance and Retreat Assist Tool100to Endoscope10]

As shown inFIG. 1A,FIG. 1B,FIG. 4A, andFIG. 4B, the fixing unit400fixes the base unit300to the endoscope10so that the first hole portion311faces the treatment instrument insertion hole portion35a.

At the same time, as has been described in [Attachment of Body Portion410to Treatment Instrument Insertion Cap36], the body portion410is pressed into the proximal end portion of the treatment instrument insertion cap36from the side surface of the treatment instrument insertion portion35via the cutout portion413in the diametrical direction of the body portion410as shown inFIG. 2C,FIG. 4A, andFIG. 4B, and is thereby attached to the proximal end portion of the treatment instrument insertion cap36.

As has been described in [Attachment of Support Portion430to Base Member310], the support portion430is then screwed into the third hole portion315in the central axis direction of the attachment portion400as shown inFIG. 2C,FIG. 4A, andFIG. 4Bso that the base thread groove portion315aand the proximal support thread groove portion437mesh with each other, and the support portion430is thereby attached to the base member310. Thus, the base member310is fastened to the support portion430.

As has been described in [Attachment of Body Portion410and Support Portion430], the support portion430is then screwed into the body thread groove portion411in the central axis direction of the attachment portion400as shown inFIG. 2C,FIG. 4A, andFIG. 4Bso that the body thread groove portion411and the distal end support thread groove portion431mesh with each other, and the support portion430is thereby attached to the body portion410. Thus, the body portion410is fastened to the support portion430.

In the attachment described above, the order of attachment is not specifically limited. Consequently, the advance and retreat assist tool100is attached to the treatment instrument insertion cap36.

As shown inFIG. 1A,FIG. 1B,FIG. 1C,FIG. 5A, andFIG. 5B, the body portion410rotates around the central axis35cof the treatment instrument insertion hole portion35aafter the body portion410and the support portion430have temporarily unfastened from each other so that, for example, the angle θ1>the angle θ2. The body portion410and the support portion430then fasten to each other again. As a result, the angle θ1>the angle θ2. As shown inFIG. 1AandFIG. 1B, when the advance and retreat assist tool100is attached to the endoscope10, the rotary portion700is slanted toward the central axis33aof the grasping portion33relative to the central axis35cof the treatment instrument insertion hole portion35a. The rotary portion700is then provided adjacent to the grasping portion33.

[Provision of Treatment Instrument51]

After the insertion portion20of the endoscope10is inserted into the body cavity, the treatment instrument51is inserted from the fixing portion600, and inserted through the first tubular member500, as shown inFIG. 1AandFIG. 1B. The treatment instrument51is further inserted into the endoscope10from the treatment instrument insertion portion35. As shown inFIG. 1AandFIG. 1B, the distal end portion51aof the treatment instrument51then projects from the distal opening portion35b. The length of the projecting distal end portion51aof the treatment instrument51is a desired length.

The fastening portion603rotates around the axis of the fastening portion603and thereby fastens the cylindrical portion601, and compresses the fixing member605by fastening. The fixing member605comes into close contact with the proximal end portion51bof the treatment instrument51by compression. As a result, the treatment instrument51is fixed to the advance and retreat assist tool100via the fixing portion600and the first tubular member500.

As shown inFIG. 5A, the grasping portion33is grasped by the left hand of the surgeon, the rotary portion700adjacent to the grasping portion33is operated by, for example, the little finger or third finger of the left hand, and the bending operation portion is operated by the thumb of the left hand. In this instance, as shown inFIG. 5B, the angle θ1>the angle θ2, so that the clearance60between the grasping portion33and the rotary portion700is smallest, the distance between the grasping portion33and the rotary portion700is shortest, and the rotary portion700is provided adjacent to the grasping portion33. The endoscope10is grasped and the treatment instrument51is operated to advance and retreat with one hand at the same time.

[Advance Operation of Treatment Instrument51]

When the rotary portion700is operated by, for example, the little finger or third finger of the left hand, the rotary portion700rotates in one direction around the third central axis500a. At the same time, the third tubular member805also rotates in the same manner as the rotary portion700. As a result, the spiral opening portion805dprovided in the third tubular member805also rotates.

As a result of the rotation of the spiral opening portion805d, the protrusion portion801moves in the long opening portion803dalong the direction of the third central axis500aby the spiral opening portion805d.

The first tubular member500having the distal end portion500bwith which the protrusion portion801is engaged advances along the direction of the third central axis500a. As a result, the treatment instrument51fixed to the first tubular member500advances.

Since the second tubular member803is fixed, the long opening portion803dis fixed, so that the long opening portion803dis prevented from rotating in the same manner as the spiral opening portion805d. Therefore, the protrusion portion801only moves in the long opening portion803dalong the direction of the third central axis500a. Therefore, the first tubular member500only advances along the direction of the third central axis500a, and the rotation of the first tubular member500around the third central axis500ais prevented. Similarly, the treatment instrument51only advances, and the rotation of the treatment instrument51around the third central axis500ais prevented.

The protrusion portion801abuts on one edge portion of the spiral opening portion805d, so that the advance of the first tubular member500is stopped, and the advance of the treatment instrument51is stopped.

[Retreat Operation of Treatment Instrument51]

When the rotary portion700is operated by, for example, the little finger or third finger of the left hand, the rotary portion700rotates in the other direction around the third central axis500a. At the same time, the third tubular member805also rotates in the same manner as the rotary portion700. As a result, the spiral opening portion805dprovided in the third tubular member805also rotates.

As a result of the rotation of the spiral opening portion805d, the protrusion portion801moves in the long opening portion803dalong the direction of the third central axis500aby the spiral opening portion805d.

The first tubular member500having the distal end portion500bwith which the protrusion portion801is engaged retreats along the direction of the third central axis500a. As a result, the treatment instrument51fixed to the first tubular member500retreats.

Since the second tubular member803is fixed, the long opening portion803dis fixed, so that the long opening portion803dis prevented from rotating in the same manner as the spiral opening portion805d. Therefore, the protrusion portion801only moves in the long opening portion803dalong the direction of the third central axis500a. Therefore, the first tubular member500only retreats along the direction of the third central axis500a, and the rotation of the first tubular member500around the third central axis500ais prevented. Similarly, the treatment instrument51only retreats, and the rotation of the treatment instrument51around the third central axis500ais prevented.

The protrusion portion801abuts on the other edge portion of the spiral opening portion805d, so that the retreat of the first tubular member500is stopped, and the retreat of the treatment instrument51is stopped. This also prevents the first tubular member500from coming off the rotary portion700.

[When Advance and Retreat Operations of Treatment Instrument51are not Needed]

As shown inFIG. 10andFIG. 5C, the attachment portion400attached to the treatment instrument insertion cap36rotates around the central axis35cof the treatment instrument insertion hole portion35aso that the angle θ3>the angle θ1. As a result, the advance and retreat assist tool100including the attachment portion400also rotates. As shown inFIG. 1CandFIG. 5C, the angle θ3>the angle θ1, so that the advance and retreat assist tool100is slanted away from the grasping portion33, the clearance60between the grasping portion33and the rotary portion700is widest, and the distance between the grasping portion33and the rotary portion700is longest. The interruption of the grasping by the advance and retreat assist tool100is eliminated.

The attachment portion400rotates as described above after the treatment instrument51is removed from the endoscope10.

The attachment portion400also rotates as described above after the body portion410and the support portion430have temporarily unfastened from each other. The body portion410and the support portion430will then fasten to each other again.

When the attachment portion400rotates, rotational resistance applied to the inner circumferential surface of the distal end portion of the body portion410by the edge portion of the treatment instrument insertion cap36is reduced by the cutout portion413.

Thus, according to the present embodiment, the second central axis313a(the third central axis500a) is slanted relative to the first central axis311a. The attachment portion400attaches the base unit300to the treatment instrument insertion portion35so that the base unit300is rotatable around the central axis35cof the treatment instrument insertion hole portion35a.

As a result, according to the present embodiment, as shown inFIG. 1A,FIG. 1B,FIG. 1C,FIG. 5A, andFIG. 5B, the advance and retreat assist tool100is slanted closer to the grasping portion33, and the clearance60between the grasping portion33and the rotary portion700can be smallest. Thus, according to the present embodiment, the fingers of the hand grasping the grasping portion33reach the rotary portion700without fail, the surgeon is not burdened, the operation is easier, and the endoscope10can be grasped and the treatment instrument51can be operated to advance and retreat with one hand at the same time. Moreover, according to the present embodiment, it is possible to prevent the whole endoscope10from increasing in size without interrupting one-handed advance and retreat operations.

According to the present embodiment, as shown inFIG. 1CandFIG. 5C, the advance and retreat assist tool100is slanted away from the grasping portion33, and the clearance60between the grasping portion33and the rotary portion700can be widest. Thus, according to the present embodiment, when the treatment instrument51is not advanced and retreated, the interruption of the grasping by the advance and retreat assist tool100is eliminated.

As described above, the present embodiment enables simple one-handed operations and smooth one-handed advance and retreat operations, and enables the advance and retreat assist tool100to rotate around the central axis35cof the treatment instrument insertion hole portion35ain accordance with procedures.

According to the present embodiment, as shown inFIG. 1A,FIG. 1B,FIG. 10,FIG. 5A, andFIG. 5B, the angle θ1>the angle θ2, so that the rotary portion700can be provided adjacent to the grasping portion33. Thus, the present embodiment ensures that the fingers of the hand grasping the grasping portion33can reach the rotary portion700and that the treatment instrument51can be advanced and retreated while the grasping portion33is grasped. According to the present embodiment, the surgeon can grasp the endoscope10and advance and retreat the treatment instrument51with one hand. According to the present embodiment, it is possible to prevent the endoscope10from increasing in size.

According to the present embodiment, as shown inFIG. 10andFIG. 5C, the angle θ3>the angle θ1, so that the interruption of the grasping by the advance and retreat assist tool100can be eliminated when the treatment instrument51is not advanced and retreated.

According to the present embodiment, the bending operation portion37and the switch portion39are provided in the grasping portion33. Thus, according to the present embodiment, the surgeon can operate the bending operation portion37and the switch portion39while grasping the endoscope10and advancing and retreating the treatment instrument51with one hand at the same time.

According to the present embodiment, as shown inFIG. 2C,FIG. 4A, andFIG. 4B, the support portion430is screwed into the body portion410attached to the treatment instrument insertion cap36. The support portion430then presses the edge portion of the treatment instrument insertion hole portion35ainto the body portion410, and the attachment portion400is fixed to the treatment instrument insertion portion35. As a result, according to the present embodiment, the fixing of the advance and retreat assist tool100to the endoscope10can be ensured, and the advance and retreat assist tool100can be easily separated from the endoscope10. According to the present embodiment, the attachment portion400can be easily disassembled and more efficiently cleaned.

According to the present embodiment, as shown inFIG. 2C,FIG. 4A, andFIG. 4B, the interference prevention member450can prevent the support portion430and the treatment instrument insertion cap36from damaging each other. Since the support portion430and the treatment instrument insertion cap36are in close contact with each other via the interference prevention member450, the interference prevention member450can also keep the support portion430and the treatment instrument insertion cap36watertight.

According to the present embodiment, as shown in FIG.2C,FIG. 4A, andFIG. 4B, the advance and retreat assist tool100can be easily attached to the treatment instrument insertion cap36, owing to the presence of cutout portion413. According to the present embodiment, the distal end portion of the body portion410formed as the inner flange can be caught on the edge portion36cof the treatment instrument insertion cap36formed as the outer flange due to the cutout portion413. As a result, according to the present embodiment, the support portion430can press the edge portion36cinto the body portion410, as described above. Thus, according to the present embodiment, it is possible to prevent the body portion410from coming off the treatment instrument insertion cap36. According to the present embodiment, rotational resistance can be reduced by the cutout portion413when the body portion410rotates.

According to the present embodiment, the second central axis313a(the third central axis500a) is slanted relative to the first central axis311a, and the rotary portion700rotates around the third central axis500a. The advance and retreat mechanism800converts the rotation force of the rotary portion700to an advance and retreat force, and advances and retreats the first tubular member500by the advance and retreat force. Thus, according to the present embodiment, it is possible to prevent a size increase of the endoscope10, ensure that the treatment instrument51is finely advanced and retreated by one hand grasping the grasping portion33, and avoid a burden being placed on the surgeon.

More specifically, according to the present embodiment, in the advance and retreat mechanism800, the rotation force of the rotary portion700is not transmitted directly to the first tubular member500, converted to an advance and retreat force by the second tubular member803and the third tubular member805, and transmitted indirectly to the first tubular member500. Thus, according to the present embodiment, it is possible to prevent the treatment instrument51from rapidly advancing and retreating, and finely advance and retreat the treatment instrument51.

According to the present embodiment, the treatment instrument51can be advanced and retreated by the advance and retreat mechanism800without rotating together with the rotary portion700.

According to the present embodiment, the protrusion portion801abuts on the edge portion of the spiral opening portion805d, so that the advance and retreat of the first tubular member500can be regulated, and the advance and retreat of the treatment instrument51can be regulated.

The long opening portion803dmay have a length slightly smaller than the length from one edge portion of the spiral opening portion805dto the other edge portion in the direction of the fourth central axis803a. In this case, the protrusion portion801abuts on the edge portion of the long opening portion803d, so that the advance and retreat of the first tubular member500can be regulated, and the advance and retreat of the treatment instrument51can be regulated. The regulating mechanism900is then formed by the protrusion portion801and by the edge portion of the long opening portion803d.

The long opening portion803dmay have a length substantially equal to the length from one edge portion of the spiral opening portion805dto the other edge portion in the direction of the fourth central axis803a. In this case, one edge portion of the long opening portion803dfaces one edge portion of the spiral opening portion805d, and the other edge portion of the long opening portion803dfaces the other edge portion of the spiral opening portion805d. In this case, the protrusion portion801abuts on the edge portion of the long opening portion803dand the edge portion of the spiral opening portion805d, so that the advance and retreat of the first tubular member500can be regulated, and the advance and retreat of the treatment instrument51can be regulated. The regulating mechanism900is then formed by the protrusion portion801, the edge portion of the long opening portion803d, and the edge portion of the spiral opening portion805d.

Thus, the regulating mechanism900has only to be formed by the protrusion portion801and at least one of the end portion of the spiral opening portion805dand the edge portion of the long opening portion803d.

According to the present embodiment, the support unit950can prevent the first tubular member500from moving in a direction that intersects at right angles with the direction of the third central axis500a. Thus, according to the present embodiment, the first tubular member500and the treatment instrument51can be advanced and retreated.

According to the present embodiment, it is possible to freely adjust the advance and retreat amount of the treatment instrument51by setting the length of the long opening portion803dand the length of the spiral opening portion805dto desired lengths.

According to the present embodiment, for example, the first tubular member500may have an unshown index which is provided on the outer circumferential surface of the first tubular member500and which indicates the advance and retreat position of the treatment instrument51. When the first tubular member500is exposed from the rotary portion700in accordance with the advance and retreat, the index portion is exposed from the rotary portion700. Thus, the surgeon can know the advance and retreat position of the treatment instrument51by checking the index portion.

A first modification of the first embodiment is now described with reference toFIG. 6A,FIG. 6B, andFIG. 6C. In the present modification, components different from the above components alone are described below.

In the present modification, the body portion410and the support portion430are integrated in the attachment portion400. Thus, the attachment portion400has a distal end portion400afunctioning as the body portion410, and a proximal end portion400bfunctioning as the support portion430. The distal end portion400aof the attachment portion400has the cutout portion413.

According to the present modification, the advance and retreat assist tool100can be easily fixed to the endoscope10, and the advance and retreat assist tool100can be quickly separated from the endoscope10. According to the present modification, the advance and retreat assist tool100can be easily rotated. According to the present modification, the body thread groove portion411and the distal end support thread groove portion431are obviated, and the configuration of the attachment portion400can be simpler. The present modification is best suited to a disposable attachment portion400.

A second modification of the first embodiment is now described with reference toFIG. 7AandFIG. 7B. In the present modification, components different from the above components alone are described below.

The distal end portion400aof the attachment portion400has claw portions401which extend along the central axis direction of the attachment portion400and then bend inward toward the central axis of the attachment portion400. The claw portions401are equally spaced out in the circumferential direction of the attachment portion400.

In this case, the claw portions401are elastically deformed to expand outward, and the end face of the distal end portion400aof the attachment portion400abuts on the end face of the edge portion36cof the treatment instrument insertion cap36in the central axis direction of the attachment portion400. The distal end portion400aof the attachment portion400is then attached to the treatment instrument insertion portion35when the claw portions401are closed and thus caught on the edge portion36c.

According to the present modification, the advance and retreat assist tool100can be easily fixed to the endoscope10, and the advance and retreat assist tool100can be quickly separated from the endoscope10. According to the present modification, the advance and retreat assist tool100can be easily rotated. According to the present modification, the body thread groove portion411and the distal end support thread groove portion431are obviated, and the configuration of the attachment portion400can be simpler. The present modification is best suited to a disposable attachment portion400.

A third modification of the first embodiment is now described with reference toFIG. 8. In the present modification, components different from the above components alone are described below.

The advance and retreat assist tool100has a body support portion461which supports the distal end portion of the body portion410, and an insertion support portion463which supports the proximal end portion of the treatment instrument insertion cap36. The advance and retreat assist tool100further has an urging portion465which is connected to the body support portion461and the insertion support portion463and which urges at least one of the distal end portion of the body portion410via the body support portion461and the proximal end portion of the treatment instrument insertion cap36via the insertion support portion463toward the other.

The body support portion461is formed by, for example, a plate-shaped material. The body support portion461has an engagement hole portion461awith which the distal end portion engages. When the distal end portion of the body portion410engages with the engagement hole portion461a, the body support portion461supports the distal end portion of the body portion410. The body support portion461may be formed by a pair of plate materials, and the plate materials catch the distal end portion of the body portion410from both sides to support the distal end portion of the body portion410. How the body support portion461provides support is not specifically limited as long as the body support portion461can support the distal end portion of the body portion410.

The same also applies to the insertion support portion463.

The urging portion465has, for example, a helical spring. The proximal end portion of the urging portion465is fixed to the body support portion461, and the distal end portion of the urging portion465is fixed to the insertion support portion463. The urging portion465is provided along the direction of the central axis35cof the treatment instrument insertion hole portion35a, and provides an urging force along the direction of the central axis35c. The urging portion465may be provided on both sides of the central axis35c(the distal end portion of the body portion410and the proximal end portion of the treatment instrument insertion cap36). Alternatively, although not shown, the urging portion465may be spirally provided around the distal end portion of the body portion410and the proximal end portion of the treatment instrument insertion cap36.

According to the present modification, when the advance and retreat assist tool100is fixed to the endoscope10, the fixing can be reinforced. The present modification can be incorporated into the first and second modifications. In this case, the body support portion461functions as a distal end support portion which supports the distal end portion of the attachment portion400.