Abstract:
A catheter according to an aspect of the present invention comprises a flexible tubular insert section having, in the outer surface of the distal end side of the insert section, a plurality of notches arranged in the longitudinal direction of the insert section on one side of a plane passing through the longitudinal axis of the insert section, an operating wire passed through the insert section and capable of advancing or retreating to bend the distal end side of the insert section having the notches, and a reinforcing tube put on the insert section to cover substantially the overall length of the whole region of the insert section, except the distal end side of the insert section on which the notches are formed, and to restrain longitudinal compression of the insert section.

Description:
CROSS REFERENCE 
     The present disclosure relates to subject matter contained in Japan Patent Application No. 2001-76166 filed on Mar. 16, 2001 which is expressly incorporated herein by reference in its entireties. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a catheter adapted to be inserted into a narrow region, such as a duct of a living body, and used to perform medical operations, such as injection of a contrast medium, recovery of foreign substances, extraction of cells, ablation of affected parts, insertion of a guide wire, etc. 
     A catheter that is inserted into a duct of a living body or the like, in order to perform medical operations, such as injection of a contrast medium, recovery of foreign substances, extraction of cells, ablation of affected parts, insertion of a guide wire, etc., generally comprises a flexible elongate insert section and an operating section on the hand side. The distal end side of the insert section can be bent so that the distal end of the insert section is directed toward a desired region in the living body. More specifically, the distal end side of the insert section can be bent by pushing or pulling an operating wire, which is fixedly connected to the distal end portion of the insert section, by means of the operating section on the hand side. 
     Operation for guiding the catheter into a narrow region deep in the living body is very difficult and requires considerable skill.  FIG. 12  shows the way a catheter  102  is guided through the channel of an endoscope  100  to a region near a duodenal papilla  105 , and an operative instrument  104  is inserted into a bile duct  106  through the opening of the duodenal papilla  105  by means of the catheter  102  that projects from the channel of the endoscope  100 . In this operation, the operative instrument  104  that is inserted in a lumen of the catheter  102 , cannot be inserted through the duodenal papilla  105  into the bile duct  106  unless the distal end side of an insert section  102   a  of the catheter  102  is bent to a given degree in a given direction such that the distal end of the insert section  102   a  can be exactly directed toward the opening of the duodenal papilla  105 . 
     Conventionally, various attempts have been made to direct the distal end of a catheter toward a desired region of a living body. Described in Jpn. Pat. Appln. KOKAI Publication No. 5-38342, for example, is a technique in which the distal end side of the insert section  102   a  of the catheter  102  is provided with a plurality of notches  103  that are eccentric to the axis of the insert section  102   a  so that it easily bends to the side on which the notches  103  are located, as shown in  FIG. 12 , whereby the insert section  102  can be readily directed toward the target region. 
     If the insert section  102   a  is provided with the notches  103  that are eccentric to its axis, as described in Jpn. Pat. Appln. KOKAI Publication No. 5-38342, the bending direction of the insert section  102   a  can no doubt be regulated to some degree. However, this alone cannot be said to be a radical solution. 
     In order to guide the catheter  102  to the duodenal papilla  105 , the flexible elongate insert section  102   a  of the catheter  102  is first inserted into the channel of the winding insert section of the endoscope  100  in the living body, and the distal end side of the insert section  102   a  is caused to project from the distal end of the insert section of the endoscope  100 . Thereafter, the projected distal end side of the insert section  102   a  is bent and directed toward the duodenal papilla. The key factor in this operation is to protrude the insert section  102   a  of the catheter  102  from the distal end of the insert section of the endoscope  100  with that side of the insert section  102   a  for the notches  103  directed toward the duodenal papilla  105  (upper side of the drawing), and thereafter, the distal end side of the insert section  102   a  is bent to a desired degree without failing to maintain this direction of protrusion. 
     However, the insert section  102   a  of the catheter  102  may be inserted in any direction into the channel of the endoscope  100 . Thus, if the catheter  102  is oriented when the catheter  102  starts to be inserted into the channel of the endoscope  100 , the catheter  102  may be redirected by its own rotation or the like in the channel of the endoscope  100  as the catheter  102  passes through the channel of the endoscope  100  that winds intricately in the living body. Consequently, the catheter  102  may fail to be caused to project from the endoscope  100  with that side of the insert section  102   a  for the notches  103  directed toward the duodenal papilla  105 , in some cases. 
     Even in the case where the catheter  102  can be caused to project from the endoscope  100  with that side for the notches  103  directed toward the duodenal papilla  105 , moreover, the distal end of the catheter  102  cannot be directed successfully toward the duodenal papilla  105  unless the catheter  102  is bent without changing the direction of its projection. If the distal end portion of the catheter  102  is provided with the notches  103 , in particular, the stiffness of the region with the notches  103  lowers, making it hard to steadily maintain the direction of projection of the catheter  102 . 
     Since the catheter is elongate and flexible, the catheter inevitably meanders as the distal end side of the insert section of the catheter  102  is bent by pushing or pulling the operating wire. In some cases, therefore, a stroke on the hand side cannot be transmitted successfully to the distal end side, meaning that a desired curvature cannot be obtained. If the distal end side of the insert section  102   a  cannot be bent to a necessary degree, the distal end of the catheter  102  cannot be directed successfully toward the duodenal papilla  105 . 
     Thus, if the catheter  102  cannot be caused to project from the endoscope with the specially provided notches  103  directed toward the duodenal papilla  105 , it is hard to direct the distal end of the catheter  102  toward the duodenal papilla  105 , in consequence. If the catheter  102  can be caused to project from the endoscope  100  with the notches  103  directed toward the duodenal papilla  105 , moreover, the distal end side of the catheter  102  cannot be bent to a desired degree in a desired direction unless a handling force on the hand side can be efficiently accurately transmitted to the distal end side without failing to maintain the direction of its projection. Thus, the distal end of the insert section  102   a  cannot be directed toward the duodenal papilla  105  exactly and speedily. 
     BRIEF SUMMARY OF THE INVENTION 
     Objects of the present invention are to provide catheters that can fulfill at least one of functions (1) to cause an insert section to project in a desired direction from the distal end of an endoscope, (2) to maintain the direction of projection steadily, and (3) to transmit a handling force on the hand side efficiently and accurately to the distal end side, thereby directing the distal end of the insert section toward a desired region of a living body exactly and speedily. 
     At least one of the above objects is achieved by a catheter described below. More specifically, a catheter according to an aspect of the present invention comprises: a flexible tubular insert section formed having, in the outer surface of the distal end side of the insert section, a plurality of notches arranged in the longitudinal direction of the insert section on one side of a plane passing through the longitudinal central axis of the insert section; an operating wire passed through the insert section and capable of advancing and retreating to bend the distal end side of the insert section having the notches; a reinforcing tube put on the insert section to cover substantially the overall length of the whole region of the insert section except the distal end side of the insert section on which the notches are formed, and to restrain longitudinal compression of the insert section. Preferably, at least two reinforcing wires defining one plane substantially parallel to the longitudinal axis of the insert section are arranged in the longitudinal direction of the insert section on the one side of the insert section on which the notches are formed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a schematic sectional view of an insert section of a catheter according to one embodiment of the present invention; 
         FIG. 2  is a sectional view taken along line  2 — 2  of  FIG. 1 ; 
         FIG. 3  is a sectional view taken along line  3 — 3  of  FIG. 2 ; 
         FIG. 4  is a side view of the insert section of  FIG. 1 ; 
         FIG. 5  is a sectional view of an operating section of the catheter according to the one embodiment of the present invention taken along line  5 — 5  of  FIG. 7 ; 
         FIG. 6  is a sectional view taken along line  6 — 6  of  FIG. 7 ; 
         FIG. 7  is a sectional view taken along line  7 — 7  of  FIG. 5 ; 
         FIG. 8  is a sectional view of the body of an operator that constitutes the operating section; 
         FIG. 9  is a sectional view taken along line  9 — 9  of  FIG. 8 ; 
         FIG. 10  is a sectional view taken along line  10 — 10  of  FIG. 8 ; 
         FIG. 11A  is a plan view of a tool for forming notches; 
         FIG. 11B  is a side view of the tool of  FIG. 11A ; and 
         FIG. 12  is a view showing a conventional catheter made to approach a duodenal papilla. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One embodiment of the present invention will now be described with reference to the drawings. 
       FIGS. 1 to 4  show an insert section  2  of a catheter according to the one embodiment of the present invention. As shown in the drawings, the insert section  2  is formed of a flexible tube (flexible sheath)  4  having an elongate soft multi-lumen structure. As is definitely shown in  FIG. 2 , the tube  4  is formed having a large-diameter first lumen (liquid feed passage)  3  and small-diameter second to fourth lumens  5 ,  7  and  9 , which extend throughout its length in the longitudinal direction. The central axis of the first lumen  3  has a given eccentricity to a longitudinal central axis O of the tube  4  on one side, while the respective longitudinal central axes of the small-diameter second to fourth lumens  5 ,  7  and  9  have given eccentricities to the longitudinal central axis O of the tube  4  on the other side. More specifically, the respective longitudinal central axes of the second and third lumens  5  and  7  have eccentricities to the longitudinal central axis O of the tube  4  that are opposite to and substantially equal to the eccentricity of the longitudinal central axis of the first lumen  3 . Further, the respective central axes of the lumens  5  and  7  are situated substantially symmetrically with respect to a plane that passes through the longitudinal central axis O of the tube  4  and the longitudinal central axis of the first lumen  3 . Furthermore, the longitudinal central axis of the fourth lumen  9  is much more eccentric to the longitudinal central axis O of the tube  4  than those of the second and third lumens  5  and  7  are, and is situated between the second and third lumens  5  and  7 . 
     As shown in  FIG. 1 , the outer surface of the tube  4  on the distal end side is formed having a plurality of notches (slits or portions that are lower in resistance to axial compression than the proximal end side of the tube  4  is)  10  on the opposite side of the longitudinal central axis O of the tube  4  to the first lumen  3  (i.e., on the side where the second to fourth lumens  5 ,  7  and  9  are formed). These notches  10  are formed by notching the tube  4  in a direction substantially perpendicular to its longitudinal central axis O, and are arranged at given spaces from one another in the longitudinal direction of the tube  4 . The depth of the notches  10  is adjusted to a dimension such that they completely diametrically cross the fourth lumen  9  without reaching the first lumen  3 . Thus, on the distal end side of the tube  4 , these notches  10  define a plurality of tubular portions  19  that are spaced in the longitudinal direction from one another and intermittently form a part of the fourth lumen  9 . 
       FIGS. 11A and 11B  show a tool for forming the notches  10  in the tube  4 . As shown in the drawings, a tool  60  has a longitudinal groove  61  in which the tube  4  is placed and a plurality of cross grooves  62  that cross the groove  61  at right angles to it. The shape of the cross grooves  62  corresponding to the shape of the notches  10  to be formed in the tube  4 . The width of the longitudinal groove  61  is substantially equal to the outside diameter of the tube  4 . The respective depths of the longitudinal groove  61  and the cross grooves  62  are adjusted to dimensions such that the width and depth of the notches  10  to be formed in the tube  4  can be obtained when those regions  4   a  of the tube  4  which are exposed in the cross grooves  62 , as the tool  60  is viewed sideways with the tube  4  located in the longitudinal groove  61 , are cut, as shown in  FIG. 11B . Thus, if the regions  4   a  of the tube  4  that are exposed in the cross grooves  62  as viewed sideways with the tube  4  located in the longitudinal groove  61  are cut along the shape of the cross grooves  62 , as indicated by arrows in  FIG. 11B , the notches  10  can be easily formed in a short time, and the working accuracy can be improved. 
     As is clearly shown in  FIGS. 1 and 3 , a distal end portion  11  of the tube  4  is tapered, and corresponding to this, the respective distal end portions of the second to fourth lumens  5 ,  7  and  9  define taper holes  5   a,    7   a  and  9   a.  The distal end portion of the first lumen  3  secures an inside diameter that allows injection of a desired quantity of contrast medium and insertion of a guide wire of a desired size, and forms an opening  3   a  (taper hole  5   a  is not shown). 
     An operating wire  13  for bending the distal end side of the tube  4  is movably passed through the fourth lumen  9 . At least a part of the operating wire  13  is formed of a single wire. The distal end side of the operating wire  13  passes through the tubular portions  19 , which are defined by the notches  10 , and reaches the inside of the taper hole  9   a.  A part of the distal end side is exposed to the outside through the notches  10 . In this case, the operating wire  13  is not situated beyond the outside diameter of the tube  4  at least on the distal end side of the tube  4  on which the notches  10  are formed. Further, an end tip  21  having tapered step portions is fixed to the distal end of the operating wire  13 . The end tip  21  is composed of a plurality of cylindrical portions having a profile substantially in the shape of a frustum (or having the form of a bamboo shoot) and connected in the longitudinal direction. The end tip  21  and the operating wire  13  are fixed to each other in a manner such that the distal end of the operating wire  13  is plasma-welded to the distal end of the end tip  21  with the distal end portion of the operating wire  13  passed through the bore of the end tip  21 . 
     The respective edge portions (corner portions) of the tapered step portions of the end tip  21  bite the inner surface of the tube  4  that forms the fourth lumen  9 , or more specifically, the inner surface of the taper hole  9   a,  whereby the operating wire  13  is fixed to the distal end of the tube  4  by means of the end tip  21 . Thus, if the operating wire  13  is pushed out toward the distal end side in the fourth lumen  9 , the distal end side of the tube  4  bends in the DOWN direction shown in  FIG. 1 . If the operating wire  13  is pulled toward the hand side (proximal end side) in the fourth lumen  9 , on the other hand, the distal end side of the tube  4  bends in the UP direction shown in  FIG. 1 . In order to reconfirm the fixation of the operating wire  13  to the tube  4 , the operating wire  13  may be fixedly bonded to the tube  4  with an adhesive agent applied to, for example, the leading notch  10  through which the operating wire  13  is exposed. 
     Reinforcing wires (hereinafter referred to as stabilizers)  29  are passed through the second and third lumens  5  and  7 , individually. The two stabilizers  29  define one plane P (see  FIG. 2 ) that is parallel to the longitudinal central axis O of the tube  4  (also parallel to a base  17  of each notch  10  according to the present embodiment). This plane P determines the direction of the notches  10  when the tube  4  is introduced into a living body or a channel of an endoscope. Thus, the stabilizers  29  serve to stabilize the passing and bending operations for the tube  4  in the rotating direction. The respective proximal ends of the stabilizers  29  are fixed to an operating section  40  (mentioned later) of the catheter. 
     Further, a reinforcing tube  24  formed of a heat-shrinkable tube is put on the outer peripheral surface of the tube  4 , substantially covering the overall length of the insert section  2  except the distal end side on which the notches  10  are formed. During the bending operation for the tube  4  by means of the operating wire  13 , the reinforcing tube  24  restrains longitudinal compression of the tube  4 , thereby preventing the tube  4  from meandering. 
     As shown in  FIGS. 1 and 4 , moreover, the distal end portion of the tube  4  is provided with a plurality of markings  25  that are spaced in the longitudinal direction from one another. These markings  25  can show the depth of insertion of the tube  4  in a duodenal papilla. As shown in  FIG. 3 , moreover, the distal end of the tube  4  is provided with an X-ray-impermeable tip  27  that indicates the position of the distal end of the tube  4 . 
       FIGS. 5 to 10  show the operating section (operator)  40  of the catheter according to the present invention. As shown in  FIG. 5 , the operating section  40  is composed of a connecting portion  40 A, which is connected to the insert section  2 , and an introducer  40 B and an operator  40 C that are separately connected to the proximal end of the connecting portion  40 A. The introducer  40 B is formed of a tubular body  43 , and is used to introduce the contrast medium, guide wire, etc. Further, the operator  40 C is formed of connecting pipe portion  32  and an operator body  70 , and is used to advance and retreat the operating wire  13 . 
     The operating section  40  and the insert section  2  constructed in this manner can be connected by fixedly pressing the insert section  2  into a straight portion  31   a  of a tube body  31  that forms the connecting portion  40 A. In this case, the reinforcing tube  24  of the insert section  2  extends close to the proximal end portion of the straight portion  31   a  of the tube body  31 . Further, the tube  4  of the insert section  2  extends from the inside of the straight portion  31   a  of the tube body  31  into the connecting pipe portion  32  of the operator  40 C through a second branch portion  31   c,  and terminates in the middle of the connecting pipe portion  32 . In this case, the operating wire  13  that is passed through the fourth lumen  9  of the tube  4  extends beyond the proximal end of the tube  4  into the connecting pipe portion  32 , and is connected to a slider  51  (see  FIG. 8 , mentioned later) of the operator body  70 . Further, the stabilizers  29  that are passed through the second and third lumens  5  and  7  of the tube  4  are caused to project from the proximal end of the tube  4  and turned back toward the distal end side in the connecting pipe portion  32 . Thereafter, the stabilizers  29  are inserted into the first lumen  3  and fixed in the first lumen  3  ( FIGS. 6 and 7 ). 
     As shown in  FIG. 5 , a tube  39  extends from the distal end of the body  43  of the introducer  40 B. The tube  39  extends through a first branch portion  31   b  of the tube body  31  of the connecting portion  40 A, penetrates the side wall of the tube  4  of the insert section  2 , and is pressed into the first lumen  3  of the tube  4 . Further, a mouthpiece  44  to which a syringe for injecting the contrast medium or the like is connected is formed integrally on the flank of the body  43 . In this case, the bore of the mouthpiece  44  communicates with the first lumen  3  of the insert section  2  by means of the respective bores of the body  43  and the tube  39 . If the contrast medium is injected through the mouthpiece  44 , therefore, the contrast medium can be guided into the first lumen  3  (and therefore, the contrast medium can be introduced into the living body through the end opening  3   a  of the first lumen  3 ). 
     Further, a guide wire inlet cylinder  45  is screwed into the basal part of the mouthpiece  44 . In this case, a ring-shaped elastic member  49  is interposed between the inlet cylinder  45  and the mouthpiece  44 , and the bore of the inlet cylinder  45  communicates with the bore of the mouthpiece  44  by means of the bore of the elastic member  49 . If the inlet cylinder  45  is screwed into the mouthpiece  44 , moreover, the elastic member  49  is crushed and elastically deformed so that the bore of the elastic member  49  is reduced in diameter. Accordingly, the guide wire that is inserted into the inlet cylinder  45  through an opening  45   a  of the inlet cylinder  45  is introduced into the first lumen  3  through the respective bores of the elastic member  49  and the body  43 , and can project from the end opening  3   a  of the first lumen  3 . If the inlet cylinder  45  is screwed into the body  43  to reduce the diameter of the elastic member  49  as this is done, moreover, no clearance is formed between the elastic member  49  and the guide wire that penetrates it. Thus, watertightness can be secured as the contrast medium is injected with use of the guide wire. In the case where the guide wire is not used, watertightness can be also secured by screwing the inlet cylinder  45  into the mouthpiece  44  in a like manner. 
       FIGS. 8 to 10  show a detailed configuration of the operator body  70 . As shown in  FIG. 8 , the operator body  70  is composed mainly of a body member  50  and the slider  51  that can advance and retreat in the longitudinal direction of the body member  50 . The slider  51  is provided with two finger hooks  51   a  and  51   b.  Further, the slider  51  is fitted with a wire fixing pin  53  that projects into the body member  50 . This wire fixing pin  53  is fixedly connected to the proximal end portion of the operating wire  13  that extends from the inside of the connecting pipe portion  32  into the body member  50 . 
     As is evident from  FIG. 9 , a guide hole  50   a  for guiding the slider  51  in movement is formed extending in the longitudinal direction in the body member  50 . Further, the wire fixing pin  53  that is integral with the slider  51  can also advance and retreat along the guide hole  50   a.  Furthermore, the outer peripheral surface of the wire fixing pin  53  is covered with a tube  52  that is in sliding contact with the inner surface of the guide hole  50   a  with a given coefficient of friction so that the wire fixing pin  53  can slide with the given coefficient of friction with respect to the body member  50 , and more specifically, that the moved position of the wire fixing pin  53  (and therefore, of the slider  51 ) is maintained with the tube  4  bent, whereby the bent state of the tube  4  can be maintained. 
     In order to regulate the retreat of the slider  51  to restrict the curvature of the tube  4 , moreover, the body member  50  is provided with a stopper pin  54  that extends across the guide hole  50   a  and can abut against the slider  51  (see  FIG. 10 ). 
     If the slider  51  is manually advanced or retreated, according to this configuration, therefore, the operating wire  13  is pushed or pulled, and the distal end side of the tube  4  is bent in the UP or DOWN direction within a given range that is determined by means of the stopper pin  54 . If the slider  51  is unhanded, the slider  51  is held as it is, and the bent state of the tube  4  can be maintained. 
     The following is a brief description of the way the catheter with the aforementioned configuration is endoscopically guided to, for example, a duodenal papilla. 
     As in the case shown in  FIG. 12 , the insert section of the endoscope is first inserted into a region near the duodenal papilla, and the insert section  2  of the catheter according to the present embodiment is then inserted into the channel of the insert section of the endoscope. In inserting the insert section  2  of the catheter into the channel of the endoscope, the insert section  2  is oriented (in the rotating direction) in advance so that the insert section  2  projects from the distal end of the insert section of the endoscope with the notches  10  directed toward the duodenal papilla. Thus, if the insert section  2  of the catheter of the present embodiment is previously oriented when it is inserted into the channel of the endoscope, there is no possibility of the insert section  2  being redirected by its own rotation or the like as the insert section  2  passes thereafter through the channel of the endoscope even though the insert section of the endoscope winds intricately in the living body. The reason is that the insert section  2  of the catheter of the present embodiment is provided with the two stabilizers  29  that define the one plane P parallel to the longitudinal central axis O of the insert section  2  (tube  4 ), and that the plane P determines the direction of the notches  10  when the insert section  2  is introduced into the channel of the endoscope. In consequence, therefore, the insert section  2  can be caused to project from the distal end of the endoscope with the side of the insert section  2  for the notches  10  directed toward the duodenal papilla. 
     After the distal end side of the insert section  2  of the catheter is thus caused to project from the insert section of the endoscope with the notches  10  directed toward the duodenal papilla, the distal end side of the projected insert section  12  is bent and directed toward the duodenal papilla. If the distal end side of the insert section  2  is bent by pulling the slider  51  of the operating section  40  to the hand side, the distal end of the insert section  2  can be directed successfully toward the duodenal papilla. In this case, the bending operation of the insert section  2  can also be stabilized in the rotation direction by means of the two stabilizers  29 . 
     During this bending operation, moreover, there is no possibility of the tube  4  meandering owing to the flexibility of the elongate tube  4 . This is because the reinforcing tube  24  that is formed of a heat-shrinkable tube is put on the outer peripheral surface of the tube  4 , substantially covering the overall length of the insert section  2  except the distal end side on which the notches  10  are formed, according to the present embodiment. During the bending operation of the tube  4  by means of the operating wire  13 , the reinforcing tube  24  prevents meandering of the tube  4  by restraining its compression, so that a handling force for the slider  51  on the hand side can be efficiently accurately transmitted to the distal end side. Thus, the distal end side of the insert section  2  can be bent to a desired degree, so that the distal end of the insert section  2  can be directed toward the duodenal papilla exactly and speedily. 
     During this bending operation, moreover, the stiffness of the distal end side of the tube  4  is lowered by the notches  10 , so that the distal end side can be bent with ease. Accordingly, a desired curvature can be obtained with use of a small handling force, and the eccentric form of the notches  10  can somewhat regulate the bending direction of the insert section  2  (the side with the notches  10  is easily bendable). 
     In the catheter of the present embodiment, which is thus used in combination with the endoscope, the overall length of the tube  4  is about 500 mm greater than the length of the channel of the endoscope. In the case of the present embodiment, therefore, the bent portion of the tube  4  in which the notches  10  are formed must be formed extending for a range of 500 mm from the distal end of the tube  4  to the proximal end side. 
     In the catheter of the present embodiment, as described above, the notches  10  are provided on the distal end side of the tube  4 , and further, the insert section  2  can be caused to project from the endoscope with the notches  10  directed toward the duodenal papilla by the agency of the stabilizers  29 , and the handling force on the hand side can be efficiently accurately transmitted to the distal end side by means of the reinforcing tube  24  that cooperates with the stabilizers  29 , without failing to maintain the direction of projection steadily. Thus, the distal end side of the insert section  2  can be bent to a desired degree in a desired direction, so that the distal end of the insert section  2  can be directed toward the duodenal papilla exactly and speedily. 
     If the slider  51  in the catheter of the present embodiment is unhanded, moreover, the slider  51  is held as it is, and the bent state of the tube  4  can be maintained, so that the slider  51  need not be held down to maintain the bent state. Thus, other treatments and operations, such as the manipulation of the guide wire, injection of the contrast medium, etc., can be concentrated on. 
     Although the present embodiment has been described for the case where the catheter is made to approach the duodenal papilla, it is to be understood that the catheter of the present embodiment can be caused to approach various regions of a living body as well as the duodenal papilla with the same functions and effects as aforesaid. Although the two stabilizers  29  are used in the present embodiment, moreover, three or more stabilizers may be used as long as they can define the one plane P. 
     According to the catheter of the present invention, as described above, the insert section can be caused to project in a desired direction from the distal end of the endoscope, and the direction of its projection can be maintained steadily. Further, the handling force on the hand side can be efficiently and accurately transmitted to the distal end side, so that the distal end of the insert section can be directed toward a desired region of a living body exactly and speedily.