JP7522094B2 - Endoscope overtube - Google Patents

Description

The present invention relates to an overtube for an endoscope having an inner cavity through which an endoscope is inserted.

Recently, there has been progress in the development of thin endoscopes, and it is now possible to insert the distal end of an endoscope into the bile duct via the duodenal papilla and directly observe the inside of the bile duct using a camera equipped on the endoscope, for example, instead of ERCP (endoscopic retrograde cholangiopancreatography).

Here, the path from the stomach/duodenum through the papilla to the bile duct has a section where it reverses at an acute angle, so the deflection function of the tip of the endoscope alone does not make it easy to insert it. For this reason, an overtube for an endoscope that has a balloon and a side hole near the distal end has been proposed (see Patent Documents 1 and 2). These overtubes make it easier to guide the distal end of the endoscope toward the papilla by pressing a part of the outside of the curved part against an inflated balloon while the distal end of the endoscope is curved.

However, when pressing part of the distal end of the endoscope against the inflated balloon, because the surface of the balloon is an outwardly convex curved surface (approximately spherical), if the positional relationship between the two is not set precisely, the two will move away from each other, and the reaction force from the balloon will not necessarily act in the appropriate direction, and the distal end of the endoscope may not deflect in the direction desired by the surgeon. For this reason, it is necessary to slightly shift the position of the distal end of the endoscope through trial and error, which may hinder a smooth procedure.

Japanese Unexamined Patent Publication No. 62-22623 JP 2011-131047 A

The present invention has been made in consideration of these points, and aims to provide an endoscopic overtube that enables procedures using an endoscope to be performed smoothly.

In order to achieve the above object, an overtube for an endoscope according to a first aspect of the present invention comprises:
An endoscope overtube for guiding an endoscope having a deflection function for bending a distal end portion,
a main tube having a distal end inserted into a body, a proximal end disposed outside the body, an inner cavity through which the endoscope is slidably inserted, and a side opening formed on a side wall of the distal end across the inside and outside for allowing the distal end of the endoscope to advance laterally;
a guide member having a base end rotatably supported on the distal end of the main tube so that the endoscope can take a first position in which the tip is directed toward the proximal end of the main tube and positioned generally along the side of the distal end of the main tube so as to block at least a portion of the side opening, and a second position in which the tip is positioned spaced outward from the side of the distal end of the main tube, and the guide member has a guide surface that guides the distal end of the endoscope advancing laterally from the side opening.

A procedure using an endoscopic overtube according to the first aspect of the present invention is performed, for example, as follows. First, the main tube is inserted into the body with the guide member in a first position (closed position), and the distal end of the endoscope inserted into the lumen of the main tube is positioned near the side opening. Next, the distal end of the endoscope is deflected (curved) using the deflection function of the endoscope, and is pushed appropriately as necessary to advance from the side opening, and the guide member is pushed by the distal end of the endoscope and rotated to a second position (open position). When the endoscope is further advanced, the distal end of the endoscope abuts against the guide surface of the guide member and is guided (guided), so that the deflection function of the endoscope and the reaction force from the guide surface can be appropriately used to easily advance the endoscope in the desired direction. Furthermore, compared to the prior art in which a balloon is used, it is not necessary to set the positional relationship with the endoscope so strictly, and therefore the distal end of the endoscope can be easily deflected in the direction desired by the surgeon.

In the endoscope overtube according to the first aspect of the present invention, the guide member may be composed of a member having an approximately partial cylindrical shape with the inner surface serving as the guide surface. By using the inner surface of the approximately partial cylindrical member as the guide surface, it is possible to suppress left and right vibration of the distal end portion of the endoscope, and to stabilize the direction of travel of the distal end portion of the endoscope. In this specification, the partial cylindrical shape includes a semi-cylinder shape, a semi-long cylindrical shape, a semi-elliptical cylindrical shape, etc.

In the overtube for endoscope according to the first aspect of the present invention, at least one wire may be further provided, the distal end of which is connected to the tip side of the guide member and the proximal end of which reaches the proximal end of the main tube. In this case, the wire may be slidably inserted into a wire lumen formed in the side wall of the main tube, or into a wire tube attached to the outer wall of the main tube. By pulling the wire toward the proximal end, the guide member in the second position can be rotated to the first position. When the main tube is to be pulled out of the body, the wire is pulled toward the proximal end to close the guide member, i.e., to the first position, so that the guide member can be smoothly pulled out without being caught on the lumen wall or the like in the body. In addition, by adjusting the pulling amount (or the loosening amount) of the wire, the opening angle of the guide member (the angle between the central axis at the distal end of the tube and the line connecting the base end to the tip of the guide member) can be arbitrarily changed between the first position and the second position.

In the endoscope overtube according to the first aspect of the present invention, the guide member can be adapted to open and stop in the second position by a portion of the base end interfering with a portion of the distal end of the main tube. When the guide member is rotated from the first position to the second position, it can be reliably opened and stopped in the second position.

The overtube for endoscope according to the first aspect of the present invention may further include a biasing member (closed position biasing member) that biases the guide member to the first position in the absence of an external force. When the main tube is to be pulled out from the body, the distal end of the endoscope is pulled into the lumen of the main tube from a state in which it has advanced to the side of the main tube, and the biasing force of the biasing member closes the guide member, i.e., puts it into the first position. This allows the main tube to be smoothly pulled out from the body without the guide member getting caught on the lumen wall inside the body.

Instead of the biasing member (closed position biasing member), a biasing member (open position biasing member) may be further provided that biases the guide member to the second position in the absence of an external force. When the action of an external force on the guide member is released, the biasing force of the biasing member opens the guide member, i.e., the guide member assumes the second position. This eliminates the need for such work compared to opening the guide member using, for example, a deflection function at the distal end of the endoscope, making it possible to facilitate and speed up the procedure.

In order to achieve the above object, an overtube for an endoscope according to a second aspect of the present invention comprises:
An endoscope overtube for guiding an endoscope having a deflection function for bending a distal end portion,
a main tube having a distal end inserted into the body, a proximal end disposed outside the body, and an inner lumen through which the endoscope is slidably inserted;
a joint portion having a base end connected to a distal end of the main tube, the joint portion being formed of a plurality of substantially partially cylindrical joint portions sequentially connected to each other so as to be rotatable about rotation axes substantially parallel to each other, so that the joint portion can assume a first configuration in which the central axes of the joint portions are disposed substantially along the central axial direction at the distal end of the main tube, and a second configuration in which the central axes of the joint portions are disposed curvedly so as to intersect each other sequentially;
and an operating means for changing the configuration of the articulation portion from the first configuration to the second configuration.

The procedure using the endoscopic overtube according to the second aspect of the present invention is performed, for example, as follows. First, the articulated portion is inserted into the body in a first configuration (straight configuration), and the distal end of the endoscope inserted into the lumen of the main tube is positioned near the opening of the distal end of the main tube. Next, the operating means is operated to change the configuration of the articulated portion from the first configuration to the second configuration (curved configuration). When the endoscope is further advanced in this state, the distal end of the endoscope is guided by the curved inner surface of the articulated portion (the inner surface of each articulated portion), so that the deflection function of the endoscope and the reaction force from the inner surface of the curved articulated portion can be appropriately utilized to easily advance the endoscope in the desired direction. Furthermore, compared to the prior art in which a balloon is used, it is not necessary to set the positional relationship with the endoscope so strictly, and therefore it is easy to deflect the distal end of the endoscope in the direction desired by the surgeon.

In the endoscopic overtube according to the second aspect of the present invention, the operating means may include at least one wire whose distal end is connected to the joint portion arranged at the tip and whose proximal end reaches the proximal end of the main tube. The shape of the joint portion can be changed by operating the wire at the proximal end of the main tube. In this case, the wire can be slidably inserted into a wire lumen formed in the side wall of the main tube, or into a wire tube attached to the outer wall of the main tube. The wire can be one that is pushed toward the distal end to give the joint portion the first shape and pulled toward the proximal end to give the joint portion the second shape.

FIG. 1A is a front view showing a distal end portion of an endoscope overtube according to an embodiment of the present invention with a flap closed. FIG. 1B is a cross-sectional view of the endoscope overtube of FIG. 1A. FIG. 1C is a partially exploded view of the endoscope overtube of FIG. 1A as viewed from the distal end side. FIG. 1D is a front view showing the endoscope overtube of FIG. 1A with the flap open. FIG. 1E is a front view showing a state in which an endoscope is inserted into the endoscope overtube of FIG. 1D. FIG. 2 is a diagram for explaining an example of a procedure for inserting an endoscope into the bile duct orally and via the duodenal papilla using the endoscopic overtube of FIG. 1A, and is a cross-sectional view showing a portion of the duodenum and bile duct. FIG. 3A is a front view showing a distal end portion of an overtube for an endoscope according to a second embodiment of the present invention. 3B is a perspective view showing the distal end of the endoscopic overtube of FIG. 3A. 3C is a perspective view of the distal end portion of the endoscope overtube of FIG. 3A as viewed from another direction. FIG. 4A is a front view showing a distal end portion of an overtube for an endoscope according to a third embodiment of the present invention. 4B is a perspective view showing the distal end of the endoscope overtube of FIG. 4A. FIG. 5A is a front view showing a distal end portion of an overtube for an endoscope according to a fourth embodiment of the present invention. 5B is a perspective view showing the distal end of the endoscope overtube of FIG. 5A. FIG. 6A is a front view showing a distal end portion of an overtube for an endoscope according to a fifth embodiment of the present invention, in which the articulated portion is formed in a straight line. FIG. 6B is a front view showing the distal end portion of the endoscope overtube of FIG. 6A, showing the case where the articulated portion is curved. FIG. 6C is a perspective view showing the distal end portion of the endoscope overtube of FIG. 6A, in which the articulated portion is formed in a straight line. FIG. 6D is a perspective view showing the distal end portion of the endoscope overtube of FIG. 6A, showing the articulated portion in a curved configuration.

Below, an embodiment of the present invention will be described with reference to the drawings. An endoscope overtube is a medical auxiliary device used to assist in the insertion of an endoscope into the body. The endoscope overtube according to the present invention can be used in a variety of procedures using an endoscope. Below, an example will be described in which a thin endoscope is inserted into the bile duct via the duodenal papilla.

Here, a thin endoscope is an endoscope whose distal end can be inserted directly into the bile duct via the duodenal papilla, and a specific example of this is a thin endoscope sold as a transnasal endoscope. Note that while the outer diameter (shaft diameter) of a typical oral endoscope is 10-14 mm, the outer diameter (shaft diameter) of a thin endoscope sold as a transnasal endoscope is 4.9-5.9 mm. Note that in this embodiment, an example will be described in which a thin endoscope is used orally.

1A to 1E, an endoscope overtube according to a first embodiment of the present invention will be described. The endoscope overtube 1 of this embodiment is an endoscope overtube that guides an endoscope having a deflection function for bending a distal end portion, and is generally configured to include a main tube 2, a flap (guiding member) 3, and a pair of wires 4, 4.

The main tube 2 is a long member having a distal end that is inserted into the body, a proximal end that is placed outside the body, and a lumen 2a through which an endoscope is slidably inserted. The proximal end of the lumen 2a of the main tube 2 forms an opening (not shown) for introducing the endoscope, and the distal end of the lumen 2a forms an opening 2b for advancing the endoscope. The outer diameter of the main tube 2 can be set within the range of 6 to 14 mm, and the inner diameter can be set within the range of 4 to 12 mm. The total length of the main tube 2 is approximately 700 to 1500 mm.

The material for the main tube 2 is not particularly limited as long as it is a flexible material, but a polymeric material is preferable, and among these, polyurethane, silicone resin, polyamide, polyethylene, polystyrene, polyvinyl chloride, crystalline polyether ether ketone, amorphous polyether ether ketone, polyetherimide, or a polyamide-based elastomer is particularly preferable.

At the distal end of the main tube 2, a side opening (side opening) 2c is formed by cutting the side wall in half a predetermined distance from the distal end and opening it to the side (inside and out). By pushing the distal end of the endoscope while deflecting it appropriately, the distal end of the endoscope can be advanced (protruded) to the side of the main tube 2 through this side opening 2c. The length of the side opening 2c in the central axial direction can be about 20 to 60 mm.

At the distal end of the main tube 2 (the distal end of the portion corresponding to the side opening 2c), a pair of cylindrical flap attachment holes 2d, 2d having a central axis that is approximately parallel to a direction perpendicular to the central axis at the distal end of the main tube 2 are formed. A pair of cylindrical protrusions 3a, 3a of the flap 3, which will be described later, are rotatably fitted into these flap attachment holes 2d, 2d. Note that, in this embodiment, these flap attachment holes 2d, 2d are assumed to penetrate from the inside to the outside, but may be recessed from the outside.

A pair of wire lumens 2e, 2e are formed along the inner cavity 2a, spaced apart from each other, within the side wall of the main tube 2. The distal ends of the wire lumens 2e, 2e open to the distal end surface of the portion of the main tube 2 where the side opening 2c is formed, and their proximal ends reach the proximal end of the main tube 2. These wire lumens 2e, 2e are insertion holes through which a pair of wires 4, 4 are slidably inserted.

Although not shown in the figure, a handle is attached to the proximal end of the main tube 2 so that the surgeon can easily hold it and manipulate it (push and pull it) when inserting the main tube 2 into the body. The handle is made of a roughly cylindrical member with flanges on both the distal and proximal ends, and the proximal end of the main tube 2 is inserted into a through hole that runs through the center and fixed there by adhesive or the like.

The flap 3 is supported rotatably around a rotation axis that is approximately parallel to the direction perpendicular to the central axis at the distal end of the main tube 3 so that the base end of the flap 3 can take a closed position (first position) and an open position (second position). Here, the closed position is a position (position shown in FIG. 1A) in which the tip of the flap 3 is directed toward the proximal end side of the main tube 2 and positioned approximately along the distal end of the main tube 3 so as to block a part of the side opening 2c. The open position is a position (position shown in FIG. 1D) in which the tip of the flap 3 is positioned away from the distal end of the main tube 3 to the outside. In this embodiment, the flap 3 is configured to block a part of the side opening 2c, but it may be configured to block the entire side opening 2c.

More specifically, the flap 3 is made of a member having a partially cylindrical portion of an approximately partially cylindrical shape, and the inner surface of the flap 3 serves as a guide surface for guiding the distal end of the endoscope that advances laterally from the side opening 2c. In this embodiment, the flap 3 is made of a member having a semi-cylindrical shape (half-pipe-shaped, gutter-shaped) with a cross section that is approximately semicircular, but it may also be made of a member having a semi-elliptical cylindrical shape with a cross section that is approximately semi-elliptical, obtained by cutting an ellipse in the major or minor axis direction, or a semi-elliptical cylindrical shape with a cross section that is approximately semi-elliptical, obtained by cutting an ellipse in the major or minor axis direction.

At the base end of the flap 3, a pair of cylindrical projections 3a, 3a having a central axis approximately parallel to a direction perpendicular to the central axis of the flap 3 are formed. These projections 3a, 3a are rotatably fitted into a pair of flap mounting holes 2d, 2d of the main tube 2, so that the base end of the flap 3 is rotatably supported around a rotation axis approximately parallel to a direction perpendicular to the central axis at the distal end of the main tube 2.

In this embodiment, the material constituting the flap 3 is the same as that of the main tube 2, but a different material may be used. Although not particularly limited, in this embodiment, the thickness of the flap 3 is approximately the same as that of the main tube 2, and the inner diameter of the flap 3 is the same as or slightly larger than the outer diameter of the main tube 2. The length of the flap 3 in the central axis direction (the length from the base end to the tip) can be approximately 20 to 70 mm.

A pair of wire attachment holes 3b, 3b are formed at the tip of the flap 3 and are spaced apart from each other. The wires 4, 4 have their distal ends attached (connected) to the wire attachment holes 3b, 3b of the flap 3, and are slidably inserted through a pair of wire lumens 2e, 2e of the main tube 2, with their proximal ends reaching the proximal end of the main tube 2. In this embodiment, thin wires made of metal (stainless steel, etc.) are used as the wires 4, 4. However, wires made of resin may also be used as the wires 4, 4. The diameter of the wires constituting the wires 4, 4 can be set in the range of approximately φ0.2 to 1.0 mm.

From the open position of the flap 3 shown in Fig. 1D, the flap 3 can be put into the closed position shown in Fig. 1A by operating (pulling) the wires 4, 4 at the proximal end of the main tube 2. When putting the flap 3 into the open position shown in Fig. 1D, the wires 4, 4 can be loosened to make it possible to do so.

In this embodiment, the pair of wires 4, 4 can be pulled toward the proximal end to place the flap 3 in a closed position, but are not rigid enough to push the flap 3 toward the distal end to place it in an open position. Therefore, to place the flap 3 in the open position shown in FIG. 1D, the flap 3 is placed in an open position by bending and pushing the distal end of the endoscope using the deflection function of the endoscope with the wires 4, 4 loosened (relaxed). At this time, the opening angle of the flap 3 (the angle between the central axis at the distal end of the main tube 2 and the central axis of the flap 3) can be set arbitrarily by appropriately adjusting the amount of slack in the wires 4, 4. However, the wires 4, 4 may be rigid enough to be pushed toward the distal end to place the flap 3 in an open position, and the flap 3 may be placed in an open position by operating the wires 4, 4 (pushing toward the distal end).

In the above-described embodiment, the pair of wires 4, 4 are inserted into the wire lumens 2e, 2e formed in the side wall of the main tube 2. Alternatively, a pair of tubes (wire tubes) may be attached to the outer wall of the main tube 2, and the wires 4, 4 may be inserted into the inner lumens of the wire tubes. The wire tubes may be attached to the main tube 2 in their entirety, or in part (for example, intermittently) to the main tube 2.

In addition, in the above-described embodiment, the wires 4 are a pair (two wires), but they may be a single wire (one wire). Furthermore, in the above-described embodiment, the wires 4, 4 are a pair (two wires), and the wire lumen 2e is also a pair (two wires) corresponding to these, but the wire lumen may be a single wire (one wire), and the pair of wires 4, 4 may be inserted into the single wire lumen.

In addition, when a thin metal wire such as stainless steel is used as the wire 4, 4, there is a risk that the exposed portion of the distal end of the wire 4, 4 (the portion pulled out from the wire lumen 3b, 3b) may come into contact with and damage body tissue when the flap 3 is in the open position. In order to prevent this, a protective tube made of resin may be provided and the exposed portion of the wire may be inserted into the lumen of the protective tube or may be coated with resin.

Next, the procedure for inserting an endoscope into the bile duct via the oral cavity and duodenal papilla using the above-mentioned endoscopic overtube 1 will be described with reference to Figure 2. First, the endoscope 6 is inserted into the lumen 2a of the main tube 2 (with the tip of the endoscope 6 protruding slightly from the opening 2b at the distal end of the lumen 2a of the main tube 2), and the main tube 2 is inserted together with the endoscope 6 into the oral cavity of the patient, and while observing the camera image of the endoscope 6, it is inserted into the duodenum 7a via the esophagus and stomach. This insertion is performed with the wires 4, 4 pulled toward the proximal end and the flap 3 in a closed position (closed).

Next, when the distal end of the main tube 2 reaches the back side (small intestine side) of the duodenal papilla 7b, the main tube 2 is rotated appropriately so that the side opening 2c of the main tube 2 is directed toward the papilla 7b. After that, the wires 4, 4 are relaxed (loosened) to a predetermined amount of relaxation that is set in relation to the maximum opening angle related to the open position of the flap 3. This makes the flap 3 openable. In this state, the endoscope 6 is temporarily pulled back appropriately, and the distal end of the endoscope 6 is appropriately deflected (curved) using the deflection function of the endoscope 6, and is pushed in appropriately as necessary to advance from the side opening 3c, and the flap 3 is pushed by the distal end of the endoscope 6 and rotated to an open position.

When the endoscope 6 is advanced further, the side of the distal end of the endoscope 6 (the distal end or the portion proximal to the distal end) comes into contact with the inner surface of the flap 3 and is guided therethrough, so that the endoscope 6 is pushed in while appropriately utilizing the deflection function of the endoscope and the reaction force from the flap 3, and the distal end of the endoscope 6 is inserted into the papilla 7b, and is then pushed further in to be inserted into the bile duct 7c. This allows the inside of the bile duct 7c to be directly observed using the camera image of the endoscope 6, and if there is a gallstone to be removed, for example, an appropriate treatment tool can be inserted through the treatment tool guide tube of the endoscope 6 to perform a procedure such as crushing or scraping out the gallstone.

When the necessary treatment is completed and the endoscopic overtube 1 is to be removed from the body, the endoscope 6 is either completely withdrawn or appropriately retracted into the lumen 2a, and the wires 4, 4 are pulled to bring the flap 3 into a closed position.

According to this embodiment, the distal end of the endoscope 6 is guided by contacting the inner surface of the flap 3, so that the deflection function of the endoscope 6 and the reaction force from the inner surface of the flap 3 can be appropriately used to easily advance the endoscope 6 in the desired direction. Furthermore, compared to the prior art in which a balloon is used, the positional relationship with the endoscope does not need to be set so strictly, so that the distal end of the endoscope can be easily deflected in the direction desired by the surgeon. In particular, in this embodiment, the flap 3 has a partial cylindrical shape (semi-cylindrical shape), so that the left-right deviation of the distal end of the endoscope 6 relative to the traveling direction is suppressed, and the traveling direction of the distal end of the endoscope 6 can be easily set in the desired direction.

Furthermore, when the endoscopic overtube 1 is to be pulled out from the body, the wires 4, 4 can be pulled to bring the flap 3 into a closed position, so that the tip of the flap 3 can be pulled out smoothly without getting caught on the lumen wall or the like inside the body.

Furthermore, the opening angle of the flap 3 can be changed by adjusting the amount of slack in the wires 4, 4, so that by adjusting this appropriately, it is easy to advance the distal end of the endoscope 6 in the desired direction.

Second embodiment An overtube for an endoscope according to a second embodiment of the present invention will be described with reference to Figures 3A to 3C. Components that are substantially the same as those in the first embodiment described above are given the same reference numerals, and differences will be described. That is, in the first embodiment described above, the side wall of the main tube 2 is cut in half by a predetermined distance from the distal end to form a side opening 2c that is open to the side (both inside and outside), but in the second embodiment, a side hole 2f is formed instead of this side opening 2c.

The side hole 2f is formed so as to penetrate the side wall from inside the lumen 2a of the main tube 2 to the outside. In this embodiment, the side hole 2f has a generally elliptical shape with its major axis set along the central axis of the main tube 2 in a plan view, and a generally half-elliptical shape with its major axis set along the central axis in a front view (see FIG. 3A). The base end of the flap 3 is rotatably supported in a portion of the main tube 2 distal to the side hole 2f.

The portion of the main tube 2 distal to the side hole 2f is set to a length such that when the flap 3 is rotated in the opening direction, an interference portion 3c, which is a part of the base end side of the flap 3, interferes with the distal end portion and stops the flap 3 in the open position. In this embodiment, the interference portion 3c is an arc-shaped cutout that is recessed from the base end of the flap 3 toward the tip end.

At the distal end side of the side hole 2f of the main tube 2, where the inner surface of the flap 3 faces, a coil spring 5a is provided as a biasing member that biases the flap 3 to an open position when no external force is applied, as shown in FIG. 3C. One end of the coil spring 5a is fixed to a portion near the distal end side of the side hole 2f of the main tube 2, and the other end is fixed to the inner surface of the base end of the flap 3. The coil spring 5a is a compression coil spring that is provided in a compressed state so as to bias the flap 3 in the direction of opening. Therefore, when no external force is applied, the flap 3 is in an open state (open position) at an opening angle determined by the relationship between the interference portion 3c of the flap 3 and the corresponding portion of the distal end of the main tube 2 due to the biasing force of the coil spring 5a.

Although not shown, a wire similar to the wire 4 in the first embodiment described above can be provided, and the proximal end of the wire can be pulled toward the proximal end to close the flap 3 against the biasing force of the coil spring 5a. If the wire is relaxed (loosened), the flap 3 will be in an open position due to the biasing force of the coil spring 5a, so compared to the first embodiment described above, where the flap 3 is opened by the deflection function of the distal end of the endoscope 6 or the like, these steps are not necessary, making the procedure easier and faster.

In the above, the coil spring 5a is a compression coil spring that biases the flap 3 to the open position when no external force is applied, but on the other hand, a tension coil spring that biases the flap 3 to the closed position when no external force is applied may be used. By using a tension coil spring as the coil spring 5a, the flap 3 is closed by the biasing force of the coil spring 5a when no external force is applied, and is positioned along the side of the main tube 2.

When opening the flap 3, as in the first embodiment described above, the flap 3 can be pressed outward against the biasing force of the coil spring 5a by utilizing the deflection function of the distal end of the endoscope 6, etc. From this state, by retracting the distal end of the endoscope 6 into the lumen 2a of the main tube 2, the flap 3 is brought into a closed position by the biasing force of the coil spring 5a. Therefore, even if the wire 4 used in the first embodiment described above is omitted, the flap 3 can be brought into a closed position, and the configuration can be simplified.

In addition, instead of the coil spring 5a, a torsion spring may be provided coaxially with the pivot axis (3a, 2d) of the flap 3, with one end of the torsion spring fixed to the main tube 2 and the other end fixed to the flap 3, to bias the flap 3 into an open or closed position.

Third embodiment An overtube for an endoscope according to a third embodiment of the present invention will be described with reference to Figures 4A and 4B. Note that components that are substantially the same as those in the first or second embodiment described above are given the same reference numerals, and differences will be described. That is, in the third embodiment, the coil spring 5a as in the second embodiment described above is not provided, and instead a leaf spring 5b is provided.

The leaf spring 5b is made of a curved, rectangular elastic member, one end of which is fixed to a portion of the main tube 2 that is distal to the flap 3, and the other end of which is fixed near the center of the outer surface of the flap 3. The leaf spring 5b is a biasing member that biases the flap 3 in the direction of opening. Therefore, when no external force is acting, the flap 3 is in an open state (open posture) at an opening angle determined by the relationship between the interference portion 3c of the flap 3 and the corresponding portion of the distal end of the main tube 2, due to the biasing force of the leaf spring 5b.

Although not shown, a wire similar to the wire 4 in the first embodiment described above can be provided, and the proximal end of the wire can be pulled toward the proximal end to close the flap 3 against the biasing force of the leaf spring 5b. If the wire is relaxed (loosened), the flap 3 will be in an open position due to the biasing force of the leaf spring 5b, so compared to the first embodiment described above, where the flap 3 is opened by the deflection function of the distal end of the endoscope 6 or the like, these steps are not necessary, making the procedure easier and faster.

In the above, an elastic member that biases the flap 3 to the open position when no external force is applied is used as the leaf spring 5b, but on the other hand, an elastic member that biases the flap 3 to the closed position when no external force is applied may be used. By using such a leaf spring 5b, when no external force is applied, the flap 3 is closed by the biasing force of the leaf spring 5b and is positioned along the side of the main tube 2.

When opening the flap 3, as in the first embodiment described above, the flap 3 can be pressed outward against the biasing force of the leaf spring 5b by utilizing the deflection function of the distal end of the endoscope 6, etc. From this state, by drawing the distal end of the endoscope 6 into the lumen 2a of the main tube 2, the flap 3 is brought into a closed position by the biasing force of the leaf spring 5b, so that the wire 4 used in the first embodiment described above can be omitted, and the configuration can be simplified.

5A and 5B, an endoscope overtube according to a fourth embodiment of the present invention will be described. Components that are substantially the same as those in the first to third embodiments will be given the same reference numerals, and differences will be described. That is, the fourth embodiment does not include the coil spring 5a in the second embodiment or the leaf spring 5b in the third embodiment, but instead includes a pair of rubber members 5c, 5c.

The rubber members 5c, 5c are each made of a strip-shaped elastic member, with one end of one rubber member 5c fixed to one of the two sides of the side hole 2f of the main tube 2 and the other end fixed to the corresponding one of the two sides of the flap 3, and one end of the other rubber member 5c fixed to the other of the two sides of the side hole 2f of the main tube 2 and the other end fixed to the corresponding other of the two sides of the flap 3. The rubber members 5c, 5c are biasing members that bias the flap 3 in the direction of opening. Therefore, when no external force is applied, the flap 3 is in an open state (open position) at an opening angle determined by the relationship between the interference portion 3c of the flap 3 and the corresponding portion of the distal end of the main tube 2 due to the biasing force of the rubber members 5c, 5c.

Although not shown, a wire similar to the wire 4 in the first embodiment described above can be provided, and the proximal end of the wire can be pulled toward the proximal end to close the flap 3 against the biasing force of the rubber members 5c, 5c. If the wire is relaxed (loosened), the flap 3 will be in an open position due to the biasing force of the rubber members 5c, 5c. This makes these operations unnecessary, compared to the first embodiment described above, where the flap 3 is opened by the deflection function of the distal end of the endoscope 6, etc., and thus makes the procedure easier and faster.

In the above, the rubber members 5c, 5c are elastic members that urge the flap 3 to the open position when no external force is applied, but on the other hand, an elastic member that urges the flap 3 to the closed position when no external force is applied may be used. By using such rubber members 5c, 5c, when no external force is applied, the flap 3 is closed by the urging force of the rubber members 5c, 5c and positioned along the side of the main tube 2.

When opening the flap 3, as in the first embodiment described above, the flap 3 can be pressed outward against the biasing force of the rubber members 5c, 5c by utilizing the deflection function of the distal end of the endoscope 6, etc. From this state, by retracting the distal end of the endoscope 6 into the lumen 2a of the main tube 2, the flap 3 is brought into a closed position by the biasing force of the rubber members 5c, 5c. Therefore, even if the wire 4 used in the first embodiment described above is omitted, the flap 3 can be brought into a closed position, and the configuration can be simplified.

In the above, the rubber members 5c, 5c are provided on each of the side holes 2f of the main tube 2 and both sides of the flap 3, but they may be provided on only one side.

6A to 6D, an endoscope overtube according to a fifth embodiment of the present invention will be described. The endoscope overtube 11 of this embodiment is an endoscope overtube that guides an endoscope having a deflection function for bending the distal end portion, and is generally configured to include a main tube 12, a joint portion 13, and a pair of wires (operation means) 14, 14.

The main tube 12 has substantially the same configuration as the main tube 2 of the first embodiment described above, except that it does not have the side opening 2c as in the first embodiment described above or the side hole 2f as in the second embodiment described above, so detailed description will be omitted. However, the side opening 2c as in the first embodiment described above or the side hole 2f as in the second embodiment described above may be provided.

A pair of wire lumens (not shown) are formed along the inner cavity 12a at positions 180° opposed to each other within the side wall of the main tube 12. The distal ends of the wire lumens open to the distal end face of the main tube 12, and their proximal ends reach the proximal end of the main tube 12. These wire lumens are insertion holes through which a pair of wires 14, 14 are slidably inserted.

The articulated portion 13 is formed by sequentially connecting a number of nodes 13a, and the base end side is connected so as to be continuous with the distal end of the main tube 12. The number of nodes 13a constituting the articulated portion 13 is not particularly limited, but in the figure, there are five. Each node 13a is formed from a member having an approximately partially cylindrical shape.

The central portion of the base end side of the most proximal node 13a is rotatably supported on the distal end of the main tube 12 at the 6 o'clock position, with the pair of wire lumens in the 9 o'clock and 3 o'clock directions when viewed from the distal end side of the main tube 12. The central portion of the base end side of the node 13a adjacent to the most proximal node 13a is rotatably supported on the distal end center of the most proximal node 13a, and the nodes 13a are rotatably supported on each other in the same manner, and the central portion of the base end side of the most distal node 13a is rotatably supported on the distal end center of the node 13a adjacent to the most distal node 13a. Each rotation axis connecting each node 13a to each other or connecting the most proximal node 13a to the distal end of the main tube 12 is approximately parallel to a direction perpendicular to the central axis at the distal end of the main tube 12.

By connecting each of the nodes 13a as described above, the joint portion 13 can have either a linear shape (first shape) in which the central axes of each of the nodes 13a are arranged in a substantially straight line, as shown in Figures 6A and 6C, or a curved shape (second shape) in which the central axes of each of the nodes 13a are arranged in a curved manner so as to intersect with each other in sequence, as shown in Figures 6B and 6D.

Wire support protrusions 13b, 13b are integrally provided at the center of both sides of each node 13a. Wire insertion holes are formed near the tips of the wire support protrusions 13b, 13b in a direction along the central axis of the node 13a in which they are provided. A pair of wires 14, 14 are slidably inserted into these wire insertion holes.

In this embodiment, each node 13a is made of a semi-cylindrical member having an approximately semicircular cross section, but it may also be a semi-elliptical cylindrical member having an approximately semi-elliptical cross section formed by cutting an oval in the long or short axis direction, or a semi-elliptical cylindrical member having an approximately semi-elliptical cross section formed by cutting an ellipse in the long or short axis direction.

In this embodiment, the material constituting each node 13 is the same as that of the main tube 12, but a different material may be used. Also, although not particularly limited, in this embodiment, the inner and outer diameters of each node 13a are set to be approximately the same as the inner and outer diameters of the main tube 12. The length of each node 13a in the central axis direction may be approximately 5 to 20 mm.

One of the pair of wires, wire 14, is slidably inserted through the corresponding wire support protrusion 13b of each node 13a and the corresponding wire lumen of the main tube 12. The distal end of one of the wires 14 is connected and fixed to the corresponding wire support protrusion 13b of the node 13a located at the most distal end. The proximal end of one of the wires 14 reaches the proximal end of the main tube 12. The same is true for the other wire 14.

In this embodiment, the wires 14, 14 are made of a metal (such as stainless steel) that is flexible enough to bend in accordance with the curvature of the main tube 12 and rigid enough to be pushed toward the distal end by manipulation of the proximal end of the main tube 12. However, the wires 14, 14 may also be made of a resin. The diameter of the wires 14, 14 can be set in the range of approximately φ0.2 to 1.0 mm.

The joint 13a located at the most distal end is integrally provided with a semicircular loop 15 having a substantially semicircular ring shape so as to span the wire support protrusions 13b, 13b. When the joint 13 is viewed from the distal end, the most distal joint 13a and the semicircular loop 15 form a ring shape having substantially the same diameter as the main tube 12. By doing so, when the distal end of the endoscope is inserted into the body with the distal end of the joint 13 protruding therefrom, the wires 14, 14 are tension-free, so that the joint 13 can be curved to follow the bending (deflection) of the endoscope. The semicircular loop 15 is provided because, without it, the joint 13 would not follow the bending of the distal end of the endoscope, and would get caught on the lumen wall, which could hinder insertion into the body.

By manipulating the wires 14, 14 at the proximal end of the main tube 12 (pulling them toward the proximal end) from the state in which the articulation portion 13 is in the straight shape shown in Figures 6A and 6C, the articulation portion 13 can be returned to the curved shape shown in Figures 6B and 6D. By manipulating the wires 14, 14 at the proximal end of the main tube 12 (pushing them toward the distal end) from the state in which the articulation portion 13 is in the curved shape shown in Figures 6B and 6D, the articulation portion 13 can be returned to the straight shape shown in Figures 6A and 6C.

In the above-described embodiment, a pair (two wires) of wires 14 are used, but a single wire (one wire) may also be used.

Next, a procedure will be described for inserting the endoscope 6 into the bile duct via the oral cavity and duodenal papilla using the above-mentioned endoscopic overtube 11. First, the articulated section 13 is set to a straight shape, and the endoscope 6 is inserted into the lumen 12a of the main tube 12 (with the tip of the endoscope 6 protruding from the distal end of the articulated section 13). The main tube 12 is then inserted into the oral cavity of the patient together with the endoscope 6, and while observing the camera image of the endoscope 6, the endoscope 6 is inserted into the duodenum (see reference symbol 7a in FIG. 2) via the esophagus and stomach.

Next, when the distal end of the main tube 12 reaches the side (small intestine side) beyond the duodenal papilla (see reference symbol 7b in FIG. 2), the main tube 12 is rotated appropriately so that the side (inner side) of the joint portion 13 to be curved faces the papilla side. After that, the wires 14, 14 are pulled toward the proximal end to curve the joint portion 13, and the endoscope 6 is pushed toward the distal end.

When the endoscope 6 is advanced further while also utilizing the deflection function of the distal end, the sides of the distal end of the endoscope 6 come into contact with the inner surface of each joint 13a and are guided, so that the endoscope 6 is pushed in while appropriately utilizing the deflection function of the endoscope 6 and the reaction force from the joint 13, and the distal end of the endoscope 6 is inserted into the papilla, and is further pushed in to insert it into the bile duct (see symbol 7c in Figure 2). This allows the inside of the bile duct to be directly observed using the camera image of the endoscope 6, and if there is a gallstone to be removed, for example, an appropriate treatment tool can be inserted through the treatment tool guide tube of the endoscope 6 to perform a procedure such as crushing or scraping out the gallstone.

When the necessary treatment is completed and the endoscopic overtube 11 is to be removed from the body, the endoscope 6 is pulled out entirely or appropriately retracted into the lumen 12a, and the wires 14, 14 are relaxed to bring the connection portion 13 into a relaxed state.

According to this embodiment, the distal end of the endoscope 6 is guided by contacting the inner surface of the articulated portion 13 (each articulated portion 13a), so that the deflection function of the endoscope 6 and the reaction force from the inner surface of the articulated portion 13 can be appropriately used to move the endoscope 6 in the desired direction. In addition, compared to the prior art in which a balloon is used, the positional relationship with the endoscope 6 does not need to be set so strictly, so that the distal end of the endoscope 6 can be easily deflected in the direction desired by the surgeon. In particular, in this embodiment, each articulated portion 13a has a partial cylindrical shape (semi-cylindrical shape), so that the left-right deviation of the distal end of the endoscope 6 relative to the traveling direction is suppressed, and the traveling direction of the distal end of the endoscope 6 can be easily set in the desired direction.

In addition, when the endoscopic overtube 11 is pulled out from the body, the wires 14, 14 can be relaxed to make the articulated portion 13 straight, so that the articulated portion 13 can be pulled out smoothly without getting caught on the lumen wall or the like inside the body.

Furthermore, the curvature of the curve of the articulated portion 13 can be changed by adjusting the amount of pulling (or extrusion) of the wires 14, 14, so that by adjusting this appropriately, it is easy to move the distal end of the endoscope 6 in the desired direction.

The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

1: Endoscope overtube 2: Main tube 2a: Lumen 2b: Opening 2c: Side opening (side opening portion)
2d: flap attachment hole 2e: wire lumen 2f: side hole (side opening)
3...Flap (guiding member)
3a: protrusion; 3b: wire attachment hole; 3c: interference portion; 4: wire; 5a: coil spring; 5b: leaf spring; 5c: rubber member; 6: endoscope; 7a: duodenum; 7b: duodenal papilla; 7c: bile duct; 11: endoscope overtube; 12: main tube; 12a: lumen; 13: articulation portion (guiding member);
13a: Node portion 13b: Wire support protrusion 14: Wire (operation means)
15...Semicircular loop section

Claims (5)

An endoscope overtube for guiding an endoscope having a deflection function for bending a distal end portion,
a main tube having a distal end inserted into the body, a proximal end disposed outside the body, and an inner lumen through which the endoscope is slidably inserted;
a joint portion having a base end connected to a distal end of the main tube, the joint portion being formed of a plurality of substantially partially cylindrical joint portions sequentially connected to each other so as to be rotatable about rotation axes substantially parallel to each other, so that the joint portion can assume a first configuration in which the central axes of the joint portions are disposed substantially along the central axial direction at the distal end of the main tube, and a second configuration in which the central axes of the joint portions are disposed curvedly so as to intersect each other sequentially;
and an operating means for changing the shape of the articulated portion from the first shape to the second shape. 2. The overtube for an endoscope according to claim 1 , wherein the operating means comprises at least one wire having a distal end connected to the joint located at the tip and a proximal end extending to the proximal end of the main tube. The overtube for an endoscope according to claim 2, wherein the wire is pushed toward the distal end to give the articulation portion the first shape and pulled toward the proximal end to give the articulation portion the second shape. 4. The overtube for an endoscope according to claim 2 , wherein the wire is slidably inserted through a wire lumen formed in a side wall of the main tube. 4. The overtube for an endoscope according to claim 2 , wherein the wire is slidably inserted through a wire tube attached to an outer wall of the main tube.

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