Patent Publication Number: US-11020106-B2

Title: Suturing device provided with reciprocally movable needle and circularly movable shuttle

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a bypass continuation-in-part application of International Application No. PCT/JP2017/029735 filed Aug. 21, 2017 in the Japan Patent Office acting as Receiving Office, claiming priority from Japanese Patent Application No. 2016-162287 filed Aug. 22, 2016. The entire contents of each of these applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a suturing device that secures thread-like members together with each stitch and forms stitches or knots in the thread-like members. 
     BACKGROUND 
     Technologies have been proposed for forming a loop and a knot in thread-like members that have been passed through a suturing target and for immobilizing the suturing target, including a technology that uses a suture anchor configured of metal or synthetic resin to clamp thread-like members together (see U.S. Pat. No. 7,416,556), and a technology for interlocking uneven formations pre-formed in the thread-like member itself (see U.S. Pat. No. 5,207,694). A technology has also been proposed for welding thread-like members together using heat or ultrasound (see U.S. Pat. No. 5,417,700). However, thread-like members that are fixed by clamping together, interlocking, or welding the thread-like members have less binding strength and tightening ability than thread-like members that are tied together with a knot. 
     Accordingly, various methods of forming knots to secure thread-like members by tying the thread-like members themselves are well known, and various needle grasping devices, auxiliary tools, and the like for forming knots have been proposed. 
     One technology describes forming knots through an operation similar to a manual operation in which two grasping devices are simply manipulated to control their positional relationship (see U.S. Pat. No. 5,336,230). This technology essentially requires that both grasping devices be operated. Another device is an auxiliary suturing tool that forms knots by performing a prescribed procedure (see U.S. Pat. No. 5,480,406). This technology requires that another grasper be used for transferring the thread-like member, since a knot cannot be formed with the auxiliary suturing tool alone. 
     SUMMARY 
     While various devices for tying thread-like members have been proposed, none of these devices is more than an auxiliary tool for aiding the operator in tying the thread-like members and none successfully realizes a device for forming knots easily and reliably through mechanical operations. 
     With all of the above conventional devices, a human operator must determine which side of what thread-like member to pass the grasper, when and where to grasp the thread-like member, how many times and in what direction to wrap the thread-like member, and the like and must perform such operations based solely on information the operator takes in visually and the like. Accordingly, the operator must have had sufficient training in advance and must have proficient technique in practice in order to form knots using these tools. In other words, all of these tools require skill and cannot be defined as devices that can form knots reliably through simple mechanical operations. 
     In view of the foregoing, it is an object of the present disclosure to provide a suturing device capable of easily and reliably forming stitches or knots through mechanical operations requiring only simple manipulations. 
     In order to attain the above and other objects, the present disclosure provides a suturing device that includes: a needle; and a shuttle. The needle is configured to hold a first thread-like member and is reciprocally movable forward and backward in a predetermined direction. The shuttle is circularly movable about an axis in a first moving direction and in a second moving direction opposite to the first moving direction. The axis extends in the predetermined direction. The shuttle includes: a holding portion; a first hook-shaped portion; and a second hook-shaped portion. The holding portion is configured to hold a second thread-like member. The first hook-shaped portion is a leading end portion of the shuttle in the circular movement of the shuttle in the first moving direction. The second hook-shaped portion is a leading end portion of the shuttle in the circular movement of the shuttle in the second moving direction. The first hook-shaped portion and the second hook-shaped portion are positioned opposite to each other with respect to the holding portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The particular features and advantages of the disclosure as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating an entire exterior of a suturing device according to one embodiment of the present disclosure; 
         FIG. 2  is an enlarged perspective view illustrating a distal end portion of the suturing device according to the embodiment of the present disclosure; 
         FIG. 3  is a side view of the distal end portion of the suturing device illustrated in  FIGS. 1 and 2 ; 
         FIG. 4  is an exploded perspective view illustrating each component positioned in a cylindrical member in the suturing device according to the embodiment; 
         FIG. 5  is an exploded perspective view illustrating a shuttle guide member to be inserted in the cylindrical member in the suturing device according to the embodiment; 
         FIG. 6  is a perspective view illustrating one example of a needle to be inserted in the cylindrical member in the suturing device according to the embodiment; 
         FIG. 7  is an enlarged cross-sectional view of a needle guide groove formed in a circumferential wall of the cylindrical member in the suturing device according to the embodiment; 
         FIG. 8  is a perspective view illustrating another example of a needle having a shape different from the shape of the needle illustrated in  FIG. 6 ; 
         FIG. 9  is a perspective view illustrating still another example of a needle having a shape different from the shape of the needle illustrated in  FIG. 6 ; 
         FIG. 10  is a view illustrating a distal end face of the cylindrical member from which a semispherical cap is removed and a cross section of the shuttle guide member taken along a plane passing through a shuttle guide groove in the suturing device according to the embodiment; 
         FIG. 11  is a view corresponding to  FIG. 10  and illustrating an initial state of the suturing device according to the embodiment in which a loop is formed in a first thread-like member extending from a distal end of the needle of  FIG. 6 ; 
         FIG. 12  is a view corresponding to  FIG. 10  and illustrating a state of the suturing device according to the embodiment after a right-hand rotating operation of approximately 70 degrees has been performed with a first operating handle, whereby a first hook-shaped end of a shuttle has passed through the loop; 
         FIG. 13  is a view corresponding to  FIG. 10  and illustrating a state of the suturing device according to the embodiment after a right-hand rotating operation of approximately 110 degrees has been performed with the first operating handle, whereby a circumferential center portion of the shuttle has become positioned inside the loop; 
         FIG. 14  is a view corresponding to  FIG. 10  and illustrating a state of the suturing device according to the embodiment after a right-hand rotating operation of approximately 200 degrees has been performed with the first operating handle, whereby the entire shuttle has passed through the loop and an end of a pusher has become positioned inside the loop; 
         FIG. 15  is a view corresponding to  FIG. 10  and illustrating a state of the suturing device according to the embodiment after a left-hand rotating operation of approximately 20 degrees has been performed with the first operating handle from the position illustrated in  FIG. 14 , whereby both the shuttle and pusher are in positions rotated in 180 degrees from the initial positions illustrated in  FIG. 11 ; 
         FIG. 16  is a longitudinal cross-sectional view of a distal end portion of the suturing device according to the embodiment for describing an insertion step in a single stitch forming operation with respect to a biological tissue; 
         FIG. 17  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a biological tissue fixing step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 18  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a needle piercing step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 19  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a loop forming step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 20  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a loop threading step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 21  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a loop tightening step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 22  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a hook advancing step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 23  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a hook-thread detaching step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 24  is a longitudinal cross-sectional view of the distal end portion of the suturing device according to the embodiment for describing a thread hooking step in the single stitch forming operation with respect to the biological tissue; 
         FIG. 25  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, a hook member, and the needle for describing the insertion step illustrated in  FIG. 16  and the biological tissue fixing step illustrated in  FIG. 17 ; 
         FIG. 26  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, the hook member, and the needle for describing the needle piercing step illustrated in  FIG. 18 ; 
         FIG. 27  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, the hook member, and the needle for describing the loop forming step illustrated in  FIG. 19 ; 
         FIG. 28  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, the hook member, and the needle for description of the loop threading step illustrated in  FIG. 20 ; 
         FIG. 29  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, the hook member, and the needle for description of the loop tightening step illustrated in  FIG. 21 ; 
         FIG. 30  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, the hook member, and the needle for description of the hook advancing step illustrated in  FIG. 22 ; 
         FIG. 31  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for description of the hook-thread detaching step illustrated in  FIG. 23 ; 
         FIG. 32  is a schematic view of the distal end portion of the suturing device according to the embodiment and particularly illustrating the shuttle, the hook member, and the needle for description of the thread hooking step illustrated in  FIG. 24 ; 
         FIG. 33  is a timing diagram for describing timed-relational movements of respective components those involved in the single stitch forming operation illustrated in  FIGS. 16 through 24  and  FIGS. 25 through 32  in the suturing device according to the embodiment; 
         FIG. 34  is a schematic perspective view illustrating a state where a plurality of stitches is formed annularly in succession along an inner circumferential surface of a pouch-like biological tissue, using the suturing device according to the embodiment; 
         FIG. 35  is a schematic perspective view illustrating a state where a knot is formed to prevent the stitches from unravelling after the plurality of stitches is formed over an entire circumference of the inner surface of the pouch-like biological tissue, using the suturing device according to the embodiment; 
         FIG. 36  is a schematic view illustrating a cross-section of the structures illustrated in  FIG. 35 ; 
         FIG. 37  is a developed view illustrating a state where the plurality of stitches is formed annularly in succession along the inner circumferential surface of the pouch-like biological tissue and the knot is formed following the stitches with the first thread-like member and a second thread-like member, using the suturing device according to the embodiment; 
         FIG. 38  is a schematic view of the cylindrical member of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for describing an insertion step in a half hitch forming operation; 
         FIG. 39  is a schematic view of the cylindrical member of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for describing a thread winding step in the half hitch forming operation; 
         FIG. 40  is a schematic view of the cylindrical member of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for describing a needle advancing step in the half hitch forming operation; 
         FIG. 41  is a schematic view of the cylindrical member of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for describing a loop forming step in the half hitch forming operation; 
         FIG. 42  is a schematic view of the cylindrical member of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for describing a loop threading step in the half hitch forming operation; 
         FIG. 43  is a schematic view of the cylindrical member of the suturing device according to the embodiment and particularly illustrating the shuttle and the needle for describing a needle retracting step in the half hitch forming operation; 
         FIG. 44  is a schematic view illustrating a primitive form of a knot obtained by performing a half hitch forming operation at a first stage operation and a half hitch forming operation at a second stage operation the same as the first stage operation in accordance with the half hitch forming operation attendant to  FIGS. 38 through 43 ; 
         FIG. 45  illustrates a granny knot produced by reshaping the primitive from of the knot illustrated in  FIG. 44 ; 
         FIG. 46  is a timing diagram for describing timed-relational movements of respective components those involved in the half hitch forming operation illustrated in  FIGS. 38 through 43  in the suturing device according to the embodiment, and particularly illustrating an operation pattern A in which the needle exhibits a right-hand rotation for winding the first thread-like member and the shuttle passed through the loop in the first thread-like member while moving in a right-hand circumferential direction; 
         FIG. 47  is a timing diagram for describing timed-relational movements of respective components those involved in the half hitch forming operation illustrated in  FIGS. 38 through 43  in the suturing device according to the embodiment, and particularly illustrating an operation pattern B in which the needle exhibits a left-hand rotation for winding the first thread-like member and the shuttle passed through the loop in the first thread-like member while moving in a left-hand circumferential direction; 
         FIG. 48  is a schematic view illustrating a primitive form of a knot obtained by performing a half hitch forming operation at a first stage operation and a half hitch forming operation at a second stage operation different from the first stage operation in accordance with the half hitch forming operation attendant to  FIGS. 38 through 43 ; 
         FIG. 49  illustrates a square knot produced by reshaping the primitive form of the knot illustrated in  FIG. 48 ; 
         FIG. 50  is a table illustrating a relationship between the first stage operation patterns and the second stage operation patterns and types of produced knots; 
         FIG. 51  illustrates a state where the second thread-like member held in a holding part of the shuttle has been passed through the loop formed in the first thread-like member in the operation illustrated in  FIGS. 38 and 39 ; and 
         FIG. 52  is a schematic diagram illustrating that a loop defined by a virtual axis and the first thread-like member in which the loop is formed are projected onto a projecting plane orthogonal to the virtual axis. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view illustrating an entire exterior of a suturing device  10  according to one embodiment of the present disclosure.  FIG. 2  is an enlarged perspective view illustrating a distal end portion of the suturing device  10 .  FIG. 3  is a right side view of the distal end portion of the suturing device  10  illustrated in  FIG. 2 .  FIGS. 4, 5, and 6  illustrate the various components of the suturing device  10  in various disassembled states. In the present embodiment, the upper portion of the suturing device  10  in  FIG. 1  will be called the distal end portion, and the bottom portion in  FIG. 1  the proximal end portion. 
     The suturing device  10  has a long and hollow cylindrical member  12  that is closed on the distal end. The cylindrical member  12  functions as a casing. The cylindrical member  12  is formed of two interconnected cylindrical tubes  12   a  and  12   b  having an outer diameter of several millimeters, for example. A semispherical cap  14  is fitted onto the distal end of the cylindrical member  12  (the cylindrical tube  12   a ) for closing the opening in the distal end. In use, the proximal end of the cylindrical member  12  is coupled to the distal end of a tubular coupling member  16  that is flexible like a catheter, for example. The cylindrical member  12  and the semispherical cap  14  fitted on the distal end of the cylindrical member  12  function as the casing of the suturing device  10 . 
     The suturing device  10  is provided with a first operating shaft  20 , a second operating shaft  22 , and a third operating shaft  24  that extend out from the proximal end of the cylindrical member  12  (the cylindrical tube  12   b ). The first operating shaft  20 , second operating shaft  22 , and third operating shaft  24  are flexible and serve to implement linear moving operations along the longitudinal direction of the cylindrical member  12  and rotating operations about respective axes. 
     The suturing device  10  is also provided with a first operating handle  21 , a second operating handle  23 , and a third operating handle  25  that are fixed to the proximal ends of the first operating shaft  20 , second operating shaft  22 , and third operating shaft  24 , respectively. The first operating shaft  20  is a shuttle operating shaft for operating a shuttle  26  provided in the cylindrical member  12 . The first operating handle  21  fixed to the proximal end of the first operating shaft  20  is used to remotely control the linear position of the shuttle  26  in the longitudinal direction of the cylindrical member  12  and the rotated position of the shuttle  26  about the axis of the first operating shaft  20 . The second operating shaft  22  is a needle operating shaft for operating a needle  30  provided in the cylindrical member  12 . The second operating handle  23  fixed to the proximal end of the second operating shaft  22  is used to remotely control the linear position of the needle  30  in the longitudinal direction of the cylindrical member  12  and the rotated position of the needle  30  about the axis of the second operating shaft  22 . The third operating shaft  24  is a hook operating shaft that operates a hook member  28  provided in the cylindrical member  12 . The third operating handle  25  fixed to the proximal end of the third operating shaft  24  is used to remotely control the linear position of the hook member  28  in the longitudinal direction of the cylindrical member  12  and the rotated position of the hook member  28  about the axis of the third operating shaft  24 . 
     Arrows X in  FIG. 1  illustrating rotating directions of the first operating handle  21 , second operating handle  23 , and third operating handle  25  indicate right-hand rotations. In the present embodiment described below, the state of the suturing device  10  illustrated in  FIG. 1  will be considered a reference position, the side of s the suturing device  10  on the left diagonally near side of the drawing in  FIG. 1  will be called the front side, the side of the suturing device  10  on the right diagonally far side of the drawing in  FIG. 1  will be called the rear side. Further, the side of the suturing device  10  on the right diagonally near side of the drawing in  FIG. 1  will be called the right side, and the side of the suturing device  10  on the left diagonally far side of the drawing in  FIG. 1  will be called the left side. Furthermore, the clockwise rotation of the suturing device  10  when viewing the suturing device  10  along the longitudinal direction of the cylindrical member  12  from the proximal end toward the distal end will be called the clockwise rotation (CWR) or the right-hand rotation, and the counterclockwise rotation in the same view will be called the counterclockwise rotation (CCW) or the left-hand rotation. 
     As illustrated in  FIG. 4 , the cylindrical member  12  is configured of a circumferential wall  32  having an inner wall surface  32   a . One portion of the circumferential wall  32  in the circumferential direction thereof is configured of a thick wall part  32   b  formed thicker than the other portions of the circumferential wall  32  having a uniform thickness. The thick wall part  32   b  is provided continuously along the longitudinal direction of the cylindrical member  12 . The inner wall surface  32   a  is flat along the inside of the thick wall part  32   b . In the present embodiment, the circumferential direction of the cylindrical member  12  denotes a direction around a center axis C 1  of the cylindrical member  12 . 
     A depression  34  is locally formed in one part of the cylindrical member  12  along the longitudinal direction of the same. The depression  34  is cut out from the circumferential wall  32  of the cylindrical member  12  (the cylindrical tube  12   a ) so as to form a recess in a portion of the cylindrical member  12  corresponding to the position of the thick wall part  32   b . The depression  34  penetrates the thick wall part  32   b  of the cylindrical member  12  in the thickness direction thereof (i.e., the front-rear direction which is the direction orthogonal to the left-right direction and the longitudinal direction of the cylindrical member  12 , hereinafter also called depthwise direction of the depression  34 ) and opens to expose the inside of the cylindrical member  12  to the outside thereof. The depression  34  is provided with a pair of sloped surfaces  34   a  that slope from the inner wall surface  32   a  toward the outer wall surface of the cylindrical member  12  on the distal side and proximal side of an opening  34   d  formed in the depression  34 . As will be described later in  FIG. 5 , a shuttle guide member  36  is inserted in the distal end portion of the cylindrical member  12 . When the shuttle guide member  36  is fitted into the cylindrical member  12 , a first flat surface  38  formed on an outer circumferential surface of the shuttle guide member  36  closes the opening  34   d  of the depression  34 . 
     As illustrated in  FIGS. 2, 3, and 4 , a needle guide groove  40  is formed in the thick wall part  32   b  of the cylindrical member  12  for guiding the needle  30  in the longitudinal direction of the cylindrical member  12 , i.e., in a direction parallel to the center axis C 1  of the cylindrical member  12 . Through the needle guide groove  40 , the needle  30  moves along a path K parallel to the center axis C 1  of the cylindrical member  12 . The needle  30  is reciprocated in the longitudinal direction of the cylindrical member  12  between an advanced end position (the position farthest toward the distal end of the cylindrical member  12 ) and a retracted end position (the position farthest toward the proximal end of the cylindrical member  12 ) with a stroke longer than the opening dimension Lo of the depression  34  in the longitudinal direction of the cylindrical member  12 . The opening dimension Lo is the length of a straight line leading from the intersecting point between the path K of the needle  30  and the proximal side of the depression  34  (i.e., a proximal edge  34   b  of the opening  34   d  of the depression  34 ) to the intersecting point between the path K of the needle  30  and the distal side of the depression  34  (i.e., a distal edge  34   c  of the opening  34   d  of the depression  34 ). Alternatively, the needle  30  may be reciprocated in the longitudinal direction of the cylindrical member  12  at a stroke longer than the longitudinal opening dimension Lo of the opening  34   d  that penetrates the thick wall part  32   b  of the cylindrical member  12  in the thickness direction thereof to expose a part of the path K of the needle  30  to the outside of the cylindrical member  12 . 
     In the present embodiment, movement of the needle  30  will be called “advancing” when the needle  30  advances toward the distal side of the cylindrical member  12  and “retracting” when the needle  30  is retracted toward the proximal side of the cylindrical member  12 . The distal end of the needle  30  is at the advanced end A of the path K when the needle  30  is in the advanced end position, and is at the retracted end B of the path K when the needle  30  is in the retracted end position. Since the retracted end B of the path K is closer to the proximal end of the cylindrical member  12  than the proximal edge  34   b  of the depression  34 , the needle  30  is not exposed in the depression  34  when the needle  30  is in the retracted end position. However, the needle  30  is exposed in the depression  34  when the needle  30  is in the advanced end position since the distal end of the needle  30  is at the advanced end A of the path K which is closer to the distal end of the cylindrical member  12  than the distal edge  34   c  of the depression  34 , and the proximal end of the needle  30  is at a position closer to the proximal end of the cylindrical member  12  than the proximal edge  34   b  of the depression  34 . 
       FIG. 2  illustrates the state of the needle  30  in the advanced end position. The path K of the distal end of the needle  30  extending from the retracted end B to the advanced end A passes through the depression  34  in the longitudinal direction of the cylindrical member  12 , and the needle groove  40  is in communication with the depression  34  through the sloped surfaces  34   a . The sloped surfaces  34   a  are parts of the thick wall part  32   b . Here, the outer wall surface of the depression  34  is configured by the sloped surfaces  34   a  and the first flat surface  38 . Note that the longitudinal dimension Lh of the depression  34  in the longitudinal direction of the cylindrical member  12  is greater than the depthwise dimension D of the depression  34  in the depthwise direction of the depression  34  which is the direction orthogonal to the longitudinal direction of the cylindrical member  12  (i.e., front-rear direction in the present embodiment, and the left-right direction of the drawing in  FIG. 3 ). 
     The shortest distance in the depthwise direction of the depression  34  between the outer wall surface of the depression  34  and the path K of the distal end of the needle  30  changes either continuously or intermittently along the direction in which the needle  30  moves. That is, in a plane that includes the path K for the distal end of the needle  30  and the center axis C 1  of the cylindrical member  12 , the distance in the depthwise direction of the depression  34  between the needle  30  in the advanced end position and the first flat surface  38  formed on a shuttle guide main body  52  (described later) is constant along the moving direction of the needle  30 . The distance in the depthwise direction of the depression  34  changes uniformly between the needle  30  and the sloped surfaces  34   a  sloped relative to the first flat surface  38 . The first flat surface  38  has a function for positioning biological tissue T received in the depression  34  as a suturing target. The position of the needle  30  relative to the first flat surface  38  is preset to achieve a target piercing position for the needle  30  relative to the thickness direction of the wall forming the biological tissue T. The needle guide groove  40  is formed in both the distal side of the depression  34  and the proximal side of the depression  34  in order to position the needle  30  at the target piercing position. In the present embodiment, the distance between the first flat surface  38  and needle  30  is set so that the needle  30  passes through the wall forming the biological tissue T. 
     As illustrated in the enlarged view of  FIG. 7 , a cross section of the needle guide groove  40  forms a circle R having a diameter equivalent to the outer dimension of the needle  30  in order to allow passage of the needle  30 . Part of the circle R is in communication with the flat inner wall surface  32   a  on the thick wall part  32   b  via a slit S having a width dimension smaller than the diameter of the needle guide groove  40 . 
     As illustrated in  FIG. 4 , a fitting groove  44  is formed in the cylindrical member  12  at a position on the distal side of the depression  34 . A friction member  32  formed of silicone rubber or the like is fitted into the fitting groove  44 . The friction member  42  is fitted into the fitting groove  44  so as to contact the outer surface of the needle  30  when the needle  30  has advanced passed the depression  34  of the cylindrical member  12  toward the advanced end position. A notched groove  46  is formed in the friction member  42  at a position for receiving insertion of the needle  30 . The notched groove  46  has the same cross-sectional shape as the needle guide groove  40 . This friction member  42  applies friction resistance to a first portion of a thread-like member L (hereinafter called first thread-like member L 1 ) that extends out from the distal end portion of the needle  30 , as illustrated in  FIG. 6 , when the needle  30  is retracted a prescribed amount such that its distal end moves along the path K from the advanced end A toward the retracted end B of the path K, easily forming a loop LP with a semicircular shape by causing the first thread-like member L 1  to separate from the distal end portion of the needle  30 . However, the friction member  42  is not absolutely necessary, provided that the loop LP can be formed through friction generated between the needle guide groove  40  and the first thread-like member L 1  extending from the distal end portion of the needle  30  when the needle  30  is retracted along the path K the prescribed amount such that the distal end of the needle  30  moves from the advanced end A toward the retracted end B of the path K. Alternatively, the loop LP may be formed through flexural rigidity of the thread-like member L itself. 
     In the present embodiment, a penetrating hole  48  penetrating the circumferential wall  32  of the cylindrical member  12  is provided between the depression  34  of the cylindrical member  12  and the semispherical cap  14  in the longitudinal direction of the cylindrical member  12  for confirming the operations of the shuttle  26  and the like. However, the penetrating hole  48  does not contribute to the function of the suturing device  10  for forming stitches or knots and therefore is not essential. 
     The shuttle guide member  36  illustrated in  FIG. 5  is a columnar member that shares the center axis C 1  of the cylindrical member  12  as its own center axis. The shuttle guide member  36  has an outer circumferential surface formed with the same cross-sectional shape as the inner wall surface  32   a , which constitutes the inner surface of the circumferential wall  32  of the cylindrical member  12 . When fitted into the cylindrical member  12 , the shuttle guide member  36  is capable of moving in the longitudinal direction within the cylindrical member  12  but is incapable of rotating relative to the cylindrical member  12  about the center axis C 1 . As illustrated in  FIG. 5 , the shuttle guide member  36  has a second flat surface  49  parallel to the center axis C 1  on a portion of its outer surface, forming an outer circumferential surface that is D-shaped in cross section and similar in shape to the inner wall surface  32   a  of the cylindrical member  12 . The plane passing through the second flat surface  49  is parallel to the plane passing through the first flat surface  38 , and the second flat surface  49  is separated farther than the first flat surface  38  from the center axis C 1 . 
     As illustrated in detail in  FIG. 5 , the shuttle guide member  36  is provided with the shuttle guide main body  52 , and a shuttle guide pressing member  54 . The shuttle guide main body  52  has a small-diameter fitting part  50  that protrudes toward the distal end of the cylindrical member  12 . The shuttle guide pressing member  54  is fixed to the shuttle guide main body  52  by securing pins  51  while the shuttle guide pressing member  54  is fitted over the small-diameter fitting part  50 . An annular shuttle guide groove  56  is defined between the shuttle guide main body  52  and shuttle guide pressing member  54  for guiding the shuttle  26  in a circumferential direction which is a direction around the center axis C 1 . The shuttle guide groove  56  may be formed in the inner wall of the shuttle guide pressing member  54  following the circumferential direction along the outer circumference of the shuttle  26 . 
     The advanced end portion of the first operating shaft  20  passes through the shuttle guide main body  52 , and the first operating shaft  20  is capable of rotating relative to the shuttle guide main body  52  about the center axis C 1 . An arm  60  extends radially outward from the center axis C 1  toward the inner wall surface  32   a  of the circumferential wall  32  of the cylindrical member  12  on the advanced end portion of the first operating shaft  20 . An arcuate pusher  58  is fixed to the arm  60  for contacting a circumferential end of the shuttle  26  in order to move the shuttle  26  in the circumferential direction. The pusher  58  has an arcuate shape and a circumferential length that corresponds to an angle less than 180 degrees, such as approximately 160 degrees, whose vertex is the center axis C 1  of the shuttle guide member  36 . 
     The shuttle  26  has an arcuate shape and a circumferential length that corresponds to an angle less than 180 degrees, such as approximately 160 degrees, whose vertex is the center axis C 1  of the columnar shuttle guide member  36  in which is formed the shuttle guide groove  56  for guiding the shuttle  26 . A holding part  62  is formed in the circumferential center portion of the shuttle  26 . The holding part  62  is configured of a through-hole that holds the second thread-like member L 2   a  second portion of the thread-like member L (hereinafter called second thread-like member L 2 ) depicted by a dashed line in  FIG. 11  by passing the second tread-like member L 2  through the holding part  62 . In the present embodiment, the thread-like member L is a single thread in which the first portion (first thread-like member L 1 ) is continuous with the second portion (second thread-like member L 2 ). The thread-like member L may be configured of two thread-like members including a first thread-like member L 1  and a second thread-like member L 2 . Both circumferential ends of the shuttle  26  taper away from the holding part  62  to form a first hook-shaped end  64  and a second hook-shaped end  66 , respectively, formed with sharp angled tips. 
     As illustrated in  FIG. 6 , the proximal end of the needle  30  is coupled with the second operating shaft  22 , and the needle  30  is guided in the longitudinal direction of the cylindrical member  12  along the center axis C 1  by the needle guide groove  40  formed in the cylindrical member  12 . A distal opening  68  is formed in the distal end of the needle  30 . The first thread-like member L 1  inserted through the inside of the second operating shaft  22  and needle  30  is guided out of the needle  30  through the distal opening  68 . 
     The needle guide groove  40  formed in the cylindrical member  12  is positioned such that the path K of the distal end of the needle  30  passes through the space inside the depression  34 . When an operation performed with the second operating handle  23  in a direction toward the distal side or the proximal side of the cylindrical member  12  in the longitudinal direction thereof is transmitted via the second operating shaft  22 , the needle  30  is advanced or retracted along the path K. Further, when an operation performed on the second operating handle  23  for rotating about the axis of the second operating shaft  22  is transmitted via the second operating shaft  22 , the needle  30  is rotated about its axis, wrapping the first thread-like member L 1  about the circumference of the needle  30 . 
     As illustrated by the dashed line in  FIG. 3 , for example, the path K described above is set inside the cylindrical member  12  to a range in the longitudinal direction of the cylindrical member  12  between the advanced end A positioned near the distal end of the cylindrical member  12  and the retracted end B positioned a prescribed distance into the proximal side of the cylindrical member  12  from the proximal edge  34   b  of the opening  34   d  of the depression  34 . This distance between the advanced end A and retracted end B denotes the stroke of the distal end of the needle  30 . That is, the advanced end A and retracted end B correspond to stroke ends of the distal end of the needle  30 . 
     The needle  30  is configured of a thin hollow tube having a cylindrical shape that is similar in shape to a hypodermic needle, for example. As an alternative of the needle  30 , as illustrated in  FIG. 8 , a needle  130  having an opening  70  formed in the peripheral wall near the distal end thereof in place of the distal opening  68  may be used. With this configuration, the first thread-like member L 1  is exposed from the opening  70 . As another alternative of the needle  30 , as illustrated in  FIG. 9 , a needle  230  having a thread hole  72  formed near the distal end thereof in place of the distal opening  68  may be used. With this configuration as well, the first portion thread-like member L 1  can be anchored in the thread hole  72 . 
       FIG. 10  illustrates the distal end face of the cylindrical member  12  after the semispherical cap  14  has been removed, and a cross section of the shuttle guide member  36  inside the cylindrical member  12  taken along a plane passing through the annular shuttle guide groove  56 . In other words, the drawing illustrates the shuttle guide member  36  depicted in a cross section taken through a plane orthogonal to the center axis C 1  and passing through the shuttle guide groove  56  as viewed inside the cylindrical member  12  from the distal end face with the semispherical cap  14  removed. As illustrated in  FIG. 10 , the shuttle guide groove  56  is open in the second flat surface  49  and has an opening width Wg that is larger than the width dimension Ws of a slit  76  illustrated in  FIG. 5 . Note that the first thread-like member L 1  and second thread-like member L 2  have been omitted from  FIG. 10 . 
     The slit  76  is formed in the portion of the shuttle guide member  36  positioned on the center axis C 1  side of the needle guide groove  40 . As described above, the loop LP is formed in the first thread-like member L 1  extending out of the distal end of the needle  30  when the needle  30  is retracted a prescribed distance along the path K in the direction from the advanced end A of the path K toward the retracted end B of the path K. The slit  76  configures a loop support space for accommodating the shape of the loop LP and for maintaining the shape of the loop LP. The slit  76  is formed at a length in the longitudinal direction of the path K and a depth in the radial direction of the shuttle guide member  36  reaching to the first operating shaft  20 . The slit  76  in the present embodiment is formed at the same length as the path K through the shuttle guide main body  52  and the shuttle guide pressing member  54  and at a depth that reaches the outer circumferential surface of the first operating shaft  20 . 
     The slit  76  extending in the longitudinal direction of the cylindrical member  12  and the annular shuttle guide groove  56  extending in the circumferential direction of the cylindrical member  12  intersect each other and are in communication with each other. The diameter of the annular shuttle guide groove  56  from groove bottom to groove bottom via the center axis C 1  is set larger than the twice the distance between the second flat surface  49  and center axis C 1  and is set to a diameter that passes approximately through the outer radial surface of the path K for the needle  30  guided by the needle guide groove  40 . Consequently, part of the circular path followed by the shuttle  26  that is guided by the shuttle guide groove  56  protrudes radially outward from the second flat surface  49  formed on the shuttle guide main body  52  and shuttle guide pressing member  54 . 
     When a rotating operation performed on the first operating handle  21  is transmitted through the first operating shaft  20 , the arcuate pusher  58  is rotated about the center axis C 1  in a circumferential direction, contacts one circumferential end of the shuttle  26 , and moves the shuttle  26  in the circumferential direction along the shuttle guide groove  56 . When the first operating handle  21  is operated toward the distal end or proximal end of the cylindrical member  12  along the longitudinal direction of the same, this operation is transmitted to the shuttle guide member  36  via the first operating shaft  20 . Consequently, the shuttle guide member  36  is moved relative to the cylindrical member  12  toward the distal side or proximal side in the longitudinal direction of the cylindrical member  12 . At the same time, the shuttle  26  is pushed by the shuttle guide main body  52  or shuttle guide pressing member  54  and is similarly moved relative to the needle  30  in the cylindrical member  12  toward the distal side or proximal side of the cylindrical member  12  along the longitudinal direction of the same. 
       FIGS. 11 through 15  are drawings illustrating the same view as that in  FIG. 10  to describe the sequential operations for passing the shuttle  26  through the loop LP formed inside the slit  76  by the first thread-like member L 1  extending from the distal end portion of the needle  30  through a rotating operation on the first operating handle  21 .  FIGS. 11 through 15  illustrate the shuttle  26  from the distal side of the cylindrical member  12  in the longitudinal direction. 
       FIG. 11  illustrates an initial state in which the loop LP is formed in the first thread-like member L 1  extending from the distal end portion of the needle  30  when the needle  30  is retracted the prescribed distance along the path K in a direction from the advanced end A toward the retracted end B of the path K. The second thread-like member L 2  is held in the shuttle  26 . In the initial state illustrated in  FIG. 11 , the shuttle  26  is in a left stop position, and the pusher  58  is in a right stop position. In this state, when the pusher  58  is rotated about the center axis C 1  through a right-hand rotating operation performed on the first operating handle  21 , the pusher  58  contacts the second hook-shaped end  66  of the shuttle  26  and moves the shuttle  26  in the circumferential direction along the shuttle guide groove  56 . 
       FIG. 12  illustrates a state after a right-hand rotating operation of approximately 70 degrees has been performed with the first operating handle  21 , whereby the first hook-shaped end  64  of the shuttle  26  being moved in a first moving direction, i.e., X-direction has passed through the loop LP. A second moving direction, i.e., Y-direction indicates the moving direction of the shuttle during a left-hand rotating operation on the first operating handle  21 .  FIG. 13  illustrates a state after a right-hand rotating operation of approximately 110 degrees has been completed on the first operating handle  21 , whereby the longitudinal (circumferential) center portion of the shuttle  26  has become positioned inside the loop LP.  FIG. 14  illustrates a state after a right-hand rotating operation of approximately 200 degrees has been completed on the first operating handle  21 , whereby the entire shuttle  26  has passed through the loop LP and an end of the pusher  58  has become positioned inside the loop LP. In a state illustrated in  FIG. 14 , the shuttle  26  is in a right stop position, and the pusher  58  is in a leftmost end position. Note that since the view in  FIGS. 11 through 14  is from the distal side of the cylindrical member  12  in the longitudinal direction thereof, the movement of the shuttle  26  in the drawings is depicted as left-hand rotation. 
       FIG. 15  illustrates a state after performing a reverse rotating operation (i.e., a left-hand rotation) of approximately 20 degrees on the first operating handle from the position illustrated in  FIG. 14 . Through this left-hand rotation, the shuttle  26  and the pusher  58  is pivotally moved in the Y-direction until both the shuttle  26  and pusher  58  are in positions rotated 180 degrees from their initial positions illustrated in  FIG. 11 . In this state illustrated in  FIG. 15 , the shuttle  26  is in the right stop position, and the pusher  58  is in a left stop position. 
     Through these operations illustrated in  FIGS. 11 to 15 , the second thread-like member L 2  held in the holding part  62  of the shuttle  26  is passed through the loop LP formed in the first thread-like member L 1  at the distal end portion of the needle  30  so that the second thread-like member L 2  intersects the loop LP in the first thread-like member L 1 . 
     As illustrated in  FIG. 4 , the hook member  28  in the cylindrical member  12  has a hook part  280  on its distal end portion that is curved into a hook shape, while the proximal end of the hook member  28  is coupled to the third operating shaft  24 . When the rotating operation performed with the third operating handle  25  is transmitted through the third operating shaft  24 , the hook member  28  rotates about its axis (axis of the third operating shaft  24 ) in the cylindrical member  12  and hooks or detaches from the first thread-like member L 1  or second thread-like member L 2  positioned between the needle  30  and shuttle  26 . Further, when an operation on the third operating handle  25  toward the distal side of the cylindrical member  12  or proximal side of the cylindrical member  12  in the longitudinal direction is transmitted via the third operating shaft  24 , the hook member  28  in the cylindrical member  12  forms slack or takes up slack in the first thread-like member L 1  or second thread-like member L 2  positioned between the needle  30  and shuttle  26 . 
     In other words, the hook member  28  capable of hooking a thread-like member L positioned between the needle  30  and shuttle  26  in the cylindrical member  12  is provided so as to be movable in the longitudinal direction of the cylindrical member  12 . Note that the hook member  28  may also possess a latch for opening and closing the opening in the hook part  280 . Alternatively, the hook part  280  may be configured of a shape memory alloy, and the opening in the hook part  280  may be selectively opened and closed by raising or lowering the temperature. In this case, the hook member  28  can be more easily unhooked from a thread-like member by increasing the opening in the hook part  280 . 
     A suturing target clamping mechanism  78  for placing the biological tissue T in contact with the depression  34  to immobilize the biological tissue T is provided in the cylindrical member  12 . The biological tissue T constitutes the suturing target and may be the left atrial appendage that protrudes locally as a pouch from the wall of the left ventricle of the heart, for example. The suturing target clamping mechanism  78  is configured of a balloon (expanding bag)  78   a  disposed on the outer wall surface of the circumferential wall  32  of the cylindrical member  12 . 
     For example, the suturing target clamping mechanism  78  may be disposed in an area of the cylindrical member  12  positioned on the opposite side of the center axis C 1  from the depression  34 , as illustrated in  FIG. 3 . In other words, in the suturing device  10  of the present embodiment, the depression  34  is formed in the front surface of the outer wall  32  of the cylindrical member  12 , while the suturing target clamping mechanism  78  is disposed on the rear surface thereof. 
     The suturing target clamping mechanism  78  may be configured of a plurality of balloons or a plurality of other members. In other words, instead of a balloon formed of a resin material, the suturing target clamping mechanism  78  may be configured of a metallic member, provided that the suturing target clamping mechanism  78  can immobilize the biological tissue T. A hose (not illustrated) for supplying pressurized fluid to the suturing target clamping mechanism  78  is connected to the balloon  78   a  configuring the suturing target clamping mechanism  78 . 
     Here, the positions of the shuttle  26  and needle  30  will be described using the expressions advanced end and retracted end, while the position of the hook member  28  will be described using the expressions advanced end, advanced, retracted, and retracted end. 
     Hereinafter, the shuttle  26  being in the retracted end position signifies that the shuttle  26  is positioned farther toward the retracted side in the longitudinal direction of the cylindrical member  12  than the proximal end of the cylindrical member  12 . The shuttle  26  being in the advanced end position signifies that the shuttle  26  is positioned farther toward the distal side (advanced side) in the longitudinal direction of the cylindrical member  12  than the distal edge  34   c  of the depression  34  in the cylindrical member  12 . 
     The needle  30  being in the advanced end position signifies that the distal end of the needle  30  is farther toward the distal side (advanced side) in the longitudinal direction of the cylindrical member  12  than the distal edge  34   c  of the opening  34   d  of the depression  34  in the cylindrical member  12  and farther toward the distal side (advanced side) of the cylindrical member  12  than the shuttle  26  positioned in the advanced end position. In the present embodiment, as described above, the needle  30  being in the advanced end position denotes that the distal end of the needle  30  is at the advanced end A of the path K illustrated in  FIG. 3 . The needle  30  being in the retracted end position denotes that the distal end of the needle  30  is positioned farther toward the proximal side (retracted side) in the longitudinal direction of the cylindrical member  12  than the proximal edge  34   b  of the opening  34   d  of the depression  34  in the cylindrical member  12 . In the present embodiment, as described above, the needle  30  being in the retracted end position specifies that the distal end of the needle  30  is at the retracted end B of the path K illustrated in  FIG. 3 . 
     The hook member  28  being in the advanced position denotes that the top  280   a  of the hook part  280  constituting the hook member  28  is positioned at the proximal edge  34   b  of the depression  34  in the cylindrical member  12 . The hook member  28  being at the advanced end position denotes that the tip  280   b  of the hook part  280  constituting the hook member  28  is positioned farther toward the distal side (advanced side) of the cylindrical member  12  than when the hook member  28  is in the advanced position. The hook member  28  being in the retracted position denotes that the tip  280   b  of the hook part  280  constituting the hook member  28  is positioned at the proximal end of the cylindrical member  12 . The hook member  28  being in the retracted end position denotes that the top  280   a  of the hook part  280  constituting the hook member  28  is positioned farther toward the retracted side than the proximal end of the cylindrical member  12 . 
     Next, a stitch forming operation and an ensuing knot forming operation for closing from the inside an opening in the biological tissue T, such as an opening in the pouch-like left atrial appendage at the site of an intra-atrial thrombus formation, will be described for the suturing device  10  having the structure described above. 
     &lt;Stitch Forming Operation&gt; 
       FIGS. 16 through 24  are longitudinal cross-sectional views of the suturing device  10  for describing the sequence of operations for forming a single stitch in the biological tissue T.  FIGS. 25 through 32  are schematic diagrams illustrating the sequence of operations for forming a single stitch using the shuttle  26 , hook member  28 , and needle  30 .  FIG. 33  is a timing diagram describing the operations of each member that contributes to the formation of a single stitch in the biological tissue T. 
     First, by operating the tubular coupling member  16  (see  FIG. 1 ), the distal end portion of the suturing device  10  is inserted into the pouch-like biological tissue T, as indicated at timing (a) in  FIG. 33 .  FIG. 16  is a longitudinal cross-sectional view of the suturing device  10  illustrating the initial state similar to the state illustrated in  FIG. 11 .  FIG. 25  illustrates the insertion step for inserting the distal end of the suturing device  10  into the pouch-like biological tissue T (not illustrated). In this state, the needle  30  is in the retracted end position, and the first thread-like member L 1  and second thread-like member L 2  formed continuously with the first thread-like member L 1  that extend between the distal end of the needle  30  and the holding part  62  of the shuttle  26  are hooked around the hook part  280  of the hook member  28  in the retracted position on the proximal side of the cylindrical member  12 . At this time, the hook member  28  is in the retracted position. 
     Next, a pressurized fluid is supplied through the hose (not illustrated) into the balloon  78   a  configuring the suturing target clamping mechanism  78  provided on the rear surface of the suturing device  10  that is inserted inside the pouch-like biological tissue T, as indicated at timing (b) in  FIG. 33 . As the balloon  78   a  expands from the pressurized fluid, tension is generated in the biological tissue T, causing a portion of the biological tissue T to be received and immobilized in the depression  34  of the suturing device  10 . When a portion of the biological tissue T is immobilized in the depression  34  in this way, the path K becomes aligned with a position inside the thickness of the wall constituting the biological tissue T.  FIG. 17  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state, and  FIG. 25  also illustrates this biological tissue fixing step for fixing the biological tissue T (not illustrated) with respect to the distal end portion of the suturing device  10 . 
     Next, through an operation to advance the second operating handle  23 , the needle  30  advances toward the advanced end position while the first thread-like member L 1  equivalent to the advancing distance of the needle  30  is supplied into the needle  30 , as indicated at timing (c) in  FIG. 33 . The needle  30  and the first thread-like member L 1  (needle thread (upper thread)) pass through the wall of the biological tissue T positioned in the depression  34 .  FIG. 18  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state.  FIG. 26  illustrates this needle piercing step for piercing the needle  30  into the wall of the biological tissue T (not illustrated) positioned in the depression  34 . 
     Through an operation to retract the second operating handle  23 , the needle  30  is retracted by a small prescribed amount toward the proximal side of the cylindrical member  12 , as indicated at timing (d) in  FIG. 33 . Through frictional resistance between the friction member  42  and the first thread-like member L 1  positioned outside the distal end portion of the needle  30 , a loop LP is formed at the distal end portion of the needle  30 . This loop LP is formed in the loop support space within the slit  76  provided in the shuttle guide member  36  along a radial direction of the center axis C 1 , as illustrated in  FIG. 11 .  FIG. 19  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state.  FIG. 27  illustrates this loop forming step for forming a loop LP in the first thread-like member L 1 . 
     Next, a right-hand rotating operation is performed with the first operating handle  21  to move the pusher  58  around the center axis C 1 , as indicated at timing (e) in  FIG. 33 . At this time, the pusher  58  contacts the second hook-shaped end  66  of the shuttle  26 , moving the shuttle  26  in the circumferential direction along the shuttle guide groove  56  so that the shuttle  26  passes through the loop LP, as illustrated in  FIGS. 12 through 14 .  FIG. 20  is a longitudinal cross-sectional view illustrating a state after the first operating handle  21  has undergone a right-hand rotating operation of approximately 110 degrees and illustrating the distal end portion of the suturing device  10  when the longitudinal (circumferential) center portion of the shuttle  26  is positioned inside the loop LP.  FIG. 28  illustrates a loop threading step with the shuttle  26 . Through this step, the second thread-like member L 2  held in the shuttle  26  is passed through the loop LP formed in the first thread-like member L 1  at the distal end portion of the needle  30  so that the second thread-like member L 2  intersects the loop LP of the first thread-like member L 1 . 
     Next, a retracting operation is performed on the second operating handle  23  to move the needle  30  so that the distal end of the needle  30  is retracted to a position at the retracted end B of the path K, as indicated at timing (f) in  FIG. 33 . Further, a left-hand rotating operation is performed with the first operating handle  21  to move the pusher  58  from the leftmost end position to the left stop position, as illustrated in  FIGS. 14 and 15 . Through these operations, the needle  30  is extracted from the biological tissue T, and the first thread-like member L 1  (needle thread (upper thread)) is pulled and tightened, reducing the size of the loop LP. At this time, the first thread-like member L 1  begins passing through the needle  30  and is supplied into the needle  30  in response to the retraction of the same so that the second thread-like member L 2  is not drawn into the biological tissue T. This operation produces a stitch N with thread tension, such as those illustrated in  FIGS. 34 and 35 .  FIG. 21  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state.  FIG. 29  illustrates this loop tightening step for tightening the loop LP and producing a stitch N. 
     A retracting operation is also performed on the first operating handle  21  to retract the shuttle guide member  36  to the proximal side of the cylindrical member  12  so that the shuttle  26  retained in the shuttle guide member  36  is retracted toward the retracted end position, as indicated at timing (g) in  FIG. 33 . This retracting movement of the shuttle  26  may be performed at the same time the needle  30  is retracted to the retracted end position at timing (f). In association with the retracting movement of the shuttle  26 , the third operating handle  25  is operated to advance the hook member  28  until the hook part  280  reaches a position near the distal end of the needle  30  in the advanced end position.  FIG. 22  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state.  FIG. 30  illustrates this hook advancing step for advancing the hook member  28 . When the shuttle  26  is retracted to the retracted position, the hook member  28  is advanced toward the distal end of the cylindrical member  12 . At this time, the first operating shaft  20  moves in the direction from the proximal end toward the distal end of the cylindrical member  12  a distance corresponding to half the distance that the shuttle  26  is retracted to the retracted end position. 
     Next, an advancing operation and a half-turn operation are performed on the third operating handle  25 , as indicated at timing (h) in  FIG. 33 , whereby the hook member  28  is moved farther toward the distal side of the cylindrical member  12  until the hook part  280  is separated from the loop LP, and is subsequently rotated a half turn to detach the hook part  280  from the loop LP. Further, a retracting operation is performed on the third operating handle  25 , at timing (h) in  FIG. 33  (not indicated), to move the hook member  28  from the advanced end position to a position farther toward the retracted side than the retracted end position.  FIG. 23  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state.  FIG. 31  illustrates this hook-thread detaching step for detaching the hook part  280  from the loop LP.  FIGS. 23 and 31  illustrate the state after the hook member  28  has been turned in a right-hand rotation at its advanced end position to be detached from the loop LP and subsequently retracted farther toward the retracted side than the proximal end of the cylindrical member  12 . Consequently, the hook member  28  is not illustrated in  FIGS. 23 and 32 . Subsequently, an advancing operation is performed on the third operating handle  25  to move the hook member  28  back to the advanced end position. At this time, the hook member  28  is detached from the loop LP at its advanced end position. This movement of the hook member  28  is also not indicated but is performed at the timing (h) in  FIG. 33 . 
     Next, a retracting operation is performed on the third operating handle  25 , as indicated at timing (i) in  FIG. 33 , whereby the hook member  28  is retracted to the retracted end position near the position of the shuttle  26  in the retracted end position. When the hook member  28  is in the retracted end position, the hook part  280  is detached from the first thread-like member L 1 . Subsequently, a left-hand rotating operation is performed with the third operating handle  25 . At this time, the hook member  28  is also moved slightly toward the distal side of the cylindrical member  12  so that the hook part  280  is positioned on the distal side of the cylindrical member  12  (on the advanced side) relative to the shuttle  26  while the hook member  28  is rotated one turn. The hook part  280  of the hook member  28  hooks the second thread-like member L 2  positioned between the reduced loop LP and the shuttle  26 .  FIG. 24  is a longitudinal cross-sectional view illustrating the distal end portion of the suturing device  10  in this state.  FIG. 32  illustrates this thread hooking step for hooking the second thread-like member L 2  by the hook part  280  of the hook member  28 . 
     Subsequently, the balloon  78   a  configuring the suturing target clamping mechanism  78  provided on the rear surface of the suturing device  10  is shrunk, as indicated at timing (j) in  FIG. 33 , by discharging the pressurized fluid from the balloon  78   a  through the hose (not illustrated). At the same time, an advancing operation is performed with the first operating handle  21  to advance the shuttle guide member  36  accommodating the shuttle  26  to the position illustrated in  FIG. 20 , i.e., the advanced end position, and an advancing operation and rotating operation are performed with the third operating handle  25  to advance the hook member  28  to the position illustrated in  FIG. 17  and to return the hook member  28  half turn. These operations restore the components to their positions in the initial state illustrated in  FIG. 17  for the start of a stitch. Thereafter, a plurality of stitches N are formed in sequence by repeatedly rotating the suturing device  10  within the pouch-like biological tissue T to the next stitch forming position and performing the same stitch forming operations described above.  FIG. 34  is a schematic diagram illustrating this operation. 
     After stitches N have been formed across substantially the entire inner circumferential surface of the biological tissue T, as described above, a knot M is formed with the suturing device  10  using the first thread-like member L 1  and second thread-like member L 2 , as illustrated in the sample schematic diagram of  FIG. 35 , so that the stitches N cannot unravel.  FIG. 36  is a cross-sectional view of the structures illustrated in  FIG. 35 .  FIG. 37  is a developed view illustrating a plurality of stitches N formed annularly in succession along the inner circumferential surface of the biological tissue T protruding in a pouch-like formation, and a knot M formed following the stitches N with the first thread-like member L 1  and second thread-like member L 2 . As illustrated in  FIG. 37 , the first thread-like member L 1  and second thread-like member L 2  are different portions of the same thread-like member L. The first thread-like member L 1  constitutes the section of the thread-like member L held by the needle  30  and drawn out from the distal end portion of the needle  30  to the biological tissue T, and the second thread-like member L 2  constitutes the section of the thread-like member L held in the shuttle  26  and drawn out from the shuttle  26  to the biological tissue T. 
     &lt;Knot Forming Operation&gt; 
       FIGS. 38 through 43  are schematic diagrams illustrating a sequence of operations performed with the suturing device  10  to form a half hitch using the first thread-like member L 1  and second thread-like member L 2 .  FIG. 44  is a schematic diagram illustrating the primitive form of a knot M 1  obtained by performing this half hitch forming operation twice.  FIG. 45  illustrates the granny knot M 1  produced by reshaping the primitive form in  FIG. 44 . 
       FIGS. 46 and 47  are timing diagrams illustrating the operations of members that contribute to formation of a single half hitch. The timing diagram in  FIG. 46  illustrates an operation pattern A in which the needle  30  has a right-hand rotation for winding the first thread-like member L 1  (denoted NEEDLE CWR in  FIG. 50  described later) and the shuttle  26  passes through the loop LP while moving in a right-hand circumferential direction (denoted SHUTTLE CWR in  FIG. 50  described later). The timing diagram in  FIG. 47  illustrates an operation pattern B in which the needle  30  has a left-hand rotation for winding the first portion L 1  of the thread-like member L (denoted NEEDLE CCR in  FIG. 50  described later) and the shuttle  26  passes through the loop LP while moving in a left-hand circumferential direction (denoted SHUTTLE CCR in  FIG. 50  described later). The balloon  78   a  configuring the suturing target clamping mechanism  78  is not used in the knot forming operations since the needle  30  is not inserted into the biological tissue T. Further, the hook member  28  has been omitted from  FIGS. 38 through 44 . 
     First, while the distal end portion of the suturing device  10  remains inserted in the pouch-like biological tissue T, the balloon  78   a  constituting the suturing target clamping mechanism  78  disposed on the rear surface of the suturing device  10  is reduced in size to remove the biological tissue T from the depression  34 , as indicated at timing (k) in  FIG. 46 .  FIG. 38  illustrates this initial step for forming a knot. In the initial state of this knot forming operation, the needle  30  is in the retracted end position and the hook member  28  is in the proximal side of the cylindrical member  12 , specifically, in the retracted position. 
     Next, an advancing operation performed with the second operating handle  23  advances the needle  30  a prescribed distance into the depression  34 , while a rotating operation performed with the second operating handle  23  rotates the needle  30  one right-hand turn during the needle  30  being positioned in the depression  34 , as indicated at timing (l) in  FIG. 46 . The rotation of the needle  30  causes the first portion L 1  of the thread-like member L to wrap around the needle  30 . Note that the needle  30  need not be rotated exactly one turn, but should be rotated approximately between 0.5 and 1.5 turns, for example.  FIG. 39  illustrates this thread winding step for winding the thread around the needle  30 . 
     Next, an advancing operation performed on the second operating handle  23  advances the needle  30  farther toward the distal side of the cylindrical member  12  to the advanced end position corresponding to the advanced end A of the path K, as indicated a timing (m) in  FIG. 46 .  FIG. 40  illustrates this needle advancing step for advancing the needle  30  to the advanced end position. 
     Further, a retracting operation is performed with the second operating handle  23  to retract the needle  30  a small prescribed distance toward the proximal side of the cylindrical member  12 , as indicated at timing (n) in  FIG. 46 . Through this operation, the first thread-like member L 1  positioned outside the distal end portion of the needle  30  forms a loop LP on the distal end portion of the needle  30  owing to the frictional resistance from the friction member  42 . This loop LP is formed between one end (hereinafter called first end) and another end (hereinafter called second end) of the first thread-like member L 1  so that a first intersecting point P 1  and a second intersecting point P 2  of the first thread-like member L 1  intersect each other. Here, the first intersecting point P 1  and second intersecting point P 2  are positioned in order from the second end toward the first end. The loop LP is formed in the loop support space in the slit  76  provided in the shuttle guide member  36  in the radial direction toward the center axis C 1  thereof.  FIG. 41  illustrates this loop forming step for forming the loop LP in the first thread-like member L 1 . 
     Next, a right-hand rotating operation performed on the first operating handle  21  pivotally moves the pusher  58  about the center axis C 1 , as indicated at timing (o) of  FIG. 46 . At this time, the pusher  58  contacts the second hook-shaped end  66  of the shuttle  26 , moving the shuttle  26  in a circumferential direction along the shuttle guide groove  56  so that the shuttle  26  passes through the loop LP.  FIG. 42  illustrates this loop threading step. In this step, the end of the second thread-like member L 2  held in the shuttle  26  is passed through the loop LP formed at the distal end portion of the needle  30  by the first thread-like member L 1  intersecting itself at the first intersecting point P 1  and second intersecting point P 2  in the direction from the second intersecting point P 2  toward the first intersecting point P 1  of the loop LP. Accordingly, the second thread-like member L 2  passes relative to the loop LP of the first thread-like member L 1 . 
     Next, a retracting operation is performed on the second operating handle  23  to retract the needle  30  until the distal end of the needle  30  is positioned at the retracted end B of the path K, as indicated at timing (p) in  FIG. 46 . Through this action, a half hitch is formed with the second thread-like member L 2  passing through the loop LP formed in the first thread-like member L 1  (needle thread (upper thread)).  FIG. 43  illustrates this needle retracting step for forming a half hitch. 
     The operations specified at timings (q), (r), (s), and (t) in  FIG. 46  are performed to return the shuttle  26  and hook member  28  to their initial positions and are identical to the operations at timings (g), (h), (i), and (j) in  FIG. 33  except that the balloon  78   a  configuring the suturing target clamping mechanism  78  remains reduced in size. Note that the operations at timings (q), (r), (s), and (t) in  FIG. 47  described later are also identical to those at timings (g), (h), (i), and (j) in  FIG. 33  except that the balloon  78   a  configuring the suturing target clamping mechanism  78  remains reduced in size. 
     Thereafter, the operations for forming a half hitch illustrated in  FIGS. 38 through 43  are repeated to form the primitive form of a granny knot M 1 , as illustrated in  FIG. 44 .  FIG. 45  illustrates the granny knot M 1  that is reshaped from the primitive form described above by tightening the first thread-like member L 1  and second thread-like member L 2 . In other words, the granny knot M 1  is formed by forming half hitches in two stages using the same operation pattern. After the granny knot M 1  has been formed in this way, the suturing device  10  is extracted from the biological tissue T to tighten the first thread-like member L 1  and second thread-like member L 2  and, when necessary, the same operations described above may be repeated to form an additional granny knot M 1  or the like. Subsequently, the process is completed by cutting off the ends of the first thread-like member L 1  and second thread-like member L 2 . 
       FIG. 47  differs from  FIG. 46  in that the needle  30  is rotated one left-hand turn while positioned in the depression  34  through a rotating operation on the second operating handle  23  at timing (l) to wind the first thread-like member L 1  about the needle  30 , and in that the shuttle  26  is passed through the loop LP in the left-hand circumferential direction through a left-hand rotating operation on the first operating handle  21  when passing through the shuttle  26  through the loop LP at timing (o). All other operations in  FIG. 47  are identical to those in  FIG. 46 . By performing the half hitch forming operations twice according to an operation pattern B illustrated in  FIG. 47 , the granny knot M 1  illustrated in  FIG. 45  can be obtained. 
     However, the knot M may be formed by first executing the half hitch forming operations according to an operation pattern A illustrated in  FIG. 46  and subsequently executing the half hitch forming operations according to the operation pattern B illustrated in  FIG. 47 . In this case, the primitive form of a square knot M 2  will be formed, as illustrated in  FIG. 48 .  FIG. 49  illustrates the square knot M 2  that is reshaped from the primitive form described above by tightening the first thread-like member L 1  and second thread-like member L 2 . This square knot M 2  may also be formed by first executing the half hitch forming operations according to the operation pattern B illustrated in  FIG. 47  and subsequently executing the half hitch operations according to the operation pattern A illustrated in  FIG. 46 . Hence, the square knot M 2  is formed by forming half hitches in two stages according to different operation patterns.  FIG. 50  is a table illustrating the relationships between first-stage operation patterns and second-stage operation patterns and the types of knots they produce. 
       FIG. 51  illustrates the state in which the second thread-like member L 2  held in the holding part  62  of the shuttle  26  has been passed through the loop LP formed in the first thread-like member L 1  at the distal end portion of the needle  30  through the operations from  FIGS. 38 through 42 . This loop LP may maintain an equivalent topology with a closed path. Here, the second thread-like member L 2  constituting one end portion of the thread-like member L formed continuously with the first thread-like member L 1  constituting another end portion of the thread-like member L must be passed through the loop LP formed in the first thread-like member L 1  in order to form a half hitch as a fundamental operation for forming a secure knot M. However, among the two directions in which the second thread-like member L 2  can be passed through the loop LP, one direction forms a knot and the other does not. A knot is not formed when the second thread-like member L 2  is passed in the other direction because the loop LP disappears before the second thread-like member L 2  can pass therethrough and is no longer a loop at the moment of passing. This concept will be described in greater detail with reference to  FIG. 52 . 
     In  FIG. 52  a loop LP defined by a virtual axis E and the first thread-like member L 1  in which the loop LP is formed are projected onto a projecting plane P orthogonal to the virtual axis E. When the projected image of the first thread-like member L (black lines) forms a closed path, the parts of the actual first thread-like member L 1  (white lines) projected on the intersecting point of this closed path is a multilevel intersection configured of two points on the first thread-like member L, and specifically a first intersecting point P 1  that is closer to a first position, which is a first end of the thread-like member L (the fixed end, and specifically the end on the biological tissue T side in the present embodiment), and a second intersecting point P 2  that is farther from the first position (a position inside the needle  30 ). The portion of the first thread-like member L 1  depicted with a dashed white line in  FIG. 52  indicates the portion positioned below the projecting plane P. In this state, a knot can be formed by passing the second thread-like member L 2  held in the holding part  62  of the shuttle  26  through the loop LP in a direction from the side of the second intersecting point P 2  farther from the first position toward the side of the first intersecting point P 1  closer to the first position, i.e., in the direction of the arrow indicating the virtual axis E. 
     This relationship is always satisfied regardless how the virtual axis E is established. In other words, when the loop LP is formed by the intersection of the first intersecting point P 1  nearer to the first position on the side of the biological tissue T, which is the suturing target of the first thread-like member L 1 , and the second intersecting point P 2  farther than the first intersecting point P 1  from the first position through the operations in  FIGS. 38 through 42 , a half hitch is formed by passing the holding part  62  of the shuttle  26  holding the second thread-like member L 2  through the loop LP in a direction from the side of the second intersecting point P 2  toward the side of the first intersecting point P 1 . 
     Using the example of  FIG. 52 , if the second intersecting point P 2  is a first point on the first thread-like member L 1  and the first intersecting point P 1  is a second point on the first thread-like member L 1  that is farther than the first point from the needle  30 , a knot is formed by passing the holding part  62  holding the second thread-like member L 2  through the loop LP formed by the intersection of the first point on the first thread-like member L 1  and the second point on the first thread-like member L 1  farther than the first point from the needle  30  in the direction from the first point toward the second point. The first operating shaft  20  of the embodiment is operated in this manner. 
     The suturing device  10  according to the present embodiment described above includes: a needle  30 ; and a shuttle  26 . The needle  30  is configured to hold a first thread-like member L 1  and is reciprocally movable forward and backward in a predetermined direction. The shuttle is circularly movable about a center axis C 1  in a first moving direction (X-direction) and in a second moving direction (Y-direction) opposite to the first moving direction. The axis C 1  extends in the predetermined direction. The shuttle  26  includes: a holding part  62 ; a first hook-shaped end  64 ; and a second hook-shaped end  66 . The holding part  62  is configured to hold a second thread-like member L 2 . The first hook-shaped end  64  is a leading end portion of the shuttle  26  in the circular movement of the shuttle  26  in the first moving direction. The second hook-shaped end  66  is a leading end portion of the shuttle  26  in the circular movement of the shuttle  26  in the second moving direction. The first hook-shaped end  64  and the second hook-shaped end  66  are positioned opposite to each other with respect to the holding part  62 . Since the shuttle  26  possesses the first hook-shaped end  64  and the second hook-shaped end  66  disposed on opposing sides of the holding part  62  and is capable of circularly moving in both directions about a line (the center axis C 1 ) parallel to the reciprocating direction of the needle  30 , the second thread-like member L 2  held in the holding part  62  and the loop LP intersecting the needle  30  can be made to cross each other by passing the holding part  62  sequentially through the loop LP in both directions. As a result, a stitch N or knot M can be formed easily and reliably through mechanical operations based on simple manipulations. 
     In the suturing device  10  according to the present embodiment, the first hook-shaped end  64  of the shuttle  26  has a first end with an acutely angled tip. The first hook-shaped end  64  tapers away from the holding part  62  toward the first end. The second hook-shaped end  66  of the shuttle  26  has a second end with an acutely angled tip. The second hook-shaped end  66  tapers away from the holding part  62  toward the second end. This shape allows the shuttle  26  to easily acquire the loop LP formed on the distal end portion of the needle  30 , even when the shape of the loop LP varies. 
     The suturing device  10  according to the present embodiment further includes a shuttle guide member  36 . The shuttle guide member  36  has a cylindrical shape extending in the predetermined direction and providing a circumferential direction and a center axis C 1  extending in the predetermined direction. The shuttle guide member  36  includes a shuttle guide groove  56 . The shuttle guide groove  56  is formed into an annular shape and is configured to guide the shuttle  26  in the circumferential direction. The shuttle  26  has an arcuate shape with a circumferential length corresponding to an angle less than 180 degrees whose vertex is the center axis C 1 . In this way, the shuttle  26  can be moved in the circumferential direction about the center axis C 1  of the shuttle guide member  36 . 
     The suturing device  10  according to the present embodiment further includes a first operating shaft  20 . The first operating shaft  20  is configured to move the shuttle  26  to permit one of the first hook-shaped end  64  and the second hook-shaped end  66  to acquire a loop LP formed in the first thread-like member L 1  and to permit the holding part  62  to pass through the loop LP. Accordingly, the shuttle  26  can easily be passed through the loop LP formed on the needle  30  through an operation on the first operating shaft  20 . 
     Further, in the suturing device  10  according to the present embodiment, the needle  30  is configured to form the loop LP in the first thread-like member L 1  when the needle  30  moves backward in the predetermined direction. The first operating shaft  20  is configured to move the shuttle  26  to pass through the loop LP such that the first hook-shaped end  64  is a leading end in the first moving direction and the second hook-shaped end  66  is a leading end in the second moving direction to allow the second thread-like member L 2  to pass through the loop LP. Accordingly, the second thread-like member L 2  held in the holding part  62  of the shuttle  26  can easily be passed through the loop LP formed on the needle  30  through operations of the first operating shaft  20 . 
     The suturing device  10  according to the present embodiment further includes a hollow cylindrical member  12 . The cylindrical member  12  has an elongated shape extending in the predetermined direction and is configured to accommodate therein the shuttle guide member  36 . The first operating shaft  20  has an end portion positioned frontward in the predetermined direction. The needle  30  has a distal end. The distal end of the needle  30  reciprocally moves along a path K extending in the predetermined direction. The shuttle guide member  36  includes: a shuttle guide main body  52 ; and a shuttle guide pressing member  54 . The shuttle guide main body  52  is formed with a slit  76  for providing a loop supporting space. The loop supporting space is positioned inward of the path K for the distal end of the needle  30  and in communication with the shuttle guide groove  56 . The loop supporting space is configured to accommodate therein the loop LP. The end portion of the first operating shaft  20  penetrates through the shuttle guide main body  52 . The shuttle guide pressing member  54  is fixed to the shuttle guide main body  52  and forms the shuttle guide groove  56  in cooperation with the shuttle guide main body  52  to guide the shuttle  26  in the circumferential direction. This configuration can maintain the shape of the loop LP formed on the needle  30  so that the loop LP is not interfered with by other members and does not get in the way of other members. 
     The suturing device  10  according to the present embodiment further includes a pusher  58 . The pusher  58  is configured to abut against one of the first hook-shaped end  64  and the second hook-shaped end  66  of the shuttle  26  to move the shuttle  26  along the shuttle guide groove  56 . The first operating shaft  20  has an end portion. The pusher  58  is fixed to the end portion of the first operating shaft  20 . This configuration allows the shuttle  26  to be easily moved in the circumferential directions by rotating the first operating shaft  20  about the center axis C 1 . 
     In the suturing device  10  according to the present embodiment, the pusher  58  has an arcuate shape with a circumferential length corresponding to an angle less than 180 degrees whose vertex is the center axis C 1 . Hence, by using the pusher  58  to move the shuttle  26  having an arcuate shape with a circumferential length that corresponds to an angle less than 180 degrees whose vertex is the center axis, the shuttle  26  can be passed through the loop LP formed at the distal end portion of the needle  30  each time the shuttle  26  is reciprocally moved in the circumferential directions around the center axis C 1  of the shuttle guide member  36 . 
     In the suturing device  10  of the present embodiment, the pusher  58  is spaced away in the circumferential direction from the shuttle  26  guided by the shuttle guide groove  56  in the circumferential direction. This configuration can absorb any variation in the amount that the first operating shaft  20  is operated in the right-hand (first) rotating direction to move the shuttle  26 . 
     In the suturing device  10  of the present embodiment, the shuttle guide member  36  is fitted within the cylindrical member  12  such that the shuttle guide member  36  is movable relative to the cylindrical member  12  along the center axis C 1  and non-rotatable relative to the cylindrical member  12  about the center axis C 1 . The first operating shaft  20  is connected to the shuttle guide member  36  such that the first operating shaft  20  is immovable relative to the shuttle guide member  36  along the center axis C 1  and rotatable relative to the shuttle guide member  36  about the center axis C 1 . In this way, the shuttle  26  can be moved in a circumferential direction so as to be threaded through the loop LP by rotating the first operating shaft  20  about the center axis C 1 . Further, by operating the first operating shaft  20  in a direction along the center axis C 1 , the shuttle  26  can be moved toward the proximal side of the cylindrical member  12  to tighten the second thread-like member L 2  held in the holding part  62  of the shuttle  26 . 
     In the suturing device  10  according to the present embodiment, the shuttle guide member  36  has a loop support space. The loop support space extends in the predetermined direction and is configured to accommodate therein the needle  30  positioned on the path K for the distal end of the needle  30 . With this configuration, the needle  30  positioned on the path K for the distal end of the needle  30  can be prevented from interfering with other members, and the loop LP in the first thread-like member L 1  formed at the distal end portion of the needle  30  can be positioned inside the shuttle guide groove  56 . 
     In the suturing device  10  according to the present embodiment, the cylindrical member  12  has a needle guide groove  40 . The needle guide groove  40  is configured to guide the needle  30  in the predetermined direction. With this arrangement, the needle  30  configured of a thin hollow tube can be stabilized by the needle guide groove  40  at any position along the path K of the distal end of the needle  30 , thereby enhancing the precision of the stitches N. 
     The suturing device  10  according to the present embodiment further includes a friction member  42 . The friction member  42  is disposed in the needle guide groove  40  and is contactable with the needle  30 . Through contact with the friction member  42 , the first thread-like member L 1  led out from the distal end of the needle  30  forms a loop LP on the distal end of the needle  30  when the needle  30  is retracted. 
     The suturing device  10  according to the present embodiment further includes a hook member  28 . The hook member  28  is positioned in the cylindrical member  12  and is movable in the predetermined direction. Both of the first thread-like member L 1  and the second thread-like member L 2  are parts of a single thread-like member L. The hook member  28  is configured to hook a first portion L 1  of the single thread-like member L positioned between the needle  30  and the shuttle  26 . Therefore, the formation of a plurality of stitches N is completed by forming a knot M after the last stitch N, without requiring formation of a knot M prior to the initial stitch N. Further, by retracting the hook member  28  while the hook member  28  is hooked around a second portion L 2  of the thread-like member L between the needle  30  and the shuttle  26 , the shuttle  26  can be passed through the loop LP without interference from the thread-like member L. 
     The suturing device  10  according to the present embodiment further includes: a second operating shaft  22 ; and a third operating shaft  24 . The second operating shaft  22  is connected to the needle  30 . The second operating shaft is configured to reciprocally move the needle  30  in the predetermined direction and to rotate the needle  30  about an axis of the needle  30 . The third operating shaft  24  is connected to the hook member  28 . The third operating shaft  24  is configured to reciprocally move the hook member  28  in the predetermined direction and to rotate the hook member  28  about an axis of the hook member  28 . Therefore, the needle  30  can be reciprocated along the path K by operating the second operating shaft  22  so that the second operating shaft  22  is reciprocated along the longitudinal direction of the cylindrical member  12 . Further, the first thread-like member L 1  can be wrapped around the needle  30  by operating the second operating shaft  22  so that the second operating shaft  22  rotates the needle  30  about its axis. A loop LP is formed on the needle  30  by operating the second operating shaft  22  so that the needle  30  around which the first thread-like member L 1  is wound moves toward the retracted side. Further, by rotating the third operating shaft  24  in order to rotate the hook member  28 , the hook member  28  can be detached from the second thread-like member L 2  held in the holding part  62  of the shuttle  26 , and by operating the third operating shaft  24  in the longitudinal direction of the cylindrical member  12  so as to move the hook member  28  in the retracting direction, slack can be formed in the second thread-like member L 2  held in the holding part  62  of the shuttle  26 . These operations can prevent the second thread-like member L 2  from becoming entangled when the shuttle  26  is threaded through the loop LP. Further, the hook member  28  can be rotated and detached from the second thread-like member L 2  when the shuttle  26  is moved in the retracting direction by the first operating shaft  20 . Further, slack can once again be formed in the second thread-like member L 2  by first moving the shuttle  26  in the advancing direction through the first operating shaft  20  and subsequently rotating the hook member  28  to hook the second thread-like member L 2  that has been passed through the loop LP. 
     The suturing device  10  according to the present embodiment further includes: a depression  34 ; and a suturing target clamping mechanism  78 . The depression  34  is provided at the cylindrical member and is configured to receive a biological tissue T. The suturing target clamping mechanism  78  is provided in the cylindrical member  12  and is configured to place the biological tissue T in contact with the depression  34  and to immobilize the biological tissue T relative to the cylindrical member  12 . Using the suturing target clamping mechanism  78  to immobilize the biological tissue T in contact with the depression  34  reduces any shifting of the biological tissue T during suturing, thereby improving the quality of sutures formed in the biological tissue T. Further, since the suturing target clamping mechanism  78  is configured of a balloon (expanding bag)  78   a  provided on the rear surface of the cylindrical member  12  at a position corresponding to the region in which the depression  34  is formed, the biological tissue T can be fixed in the depression  34  through a simple construction. 
     In the suturing device  10  of the present embodiment, the needle  30  has a distal end and is configured to permit the first thread-like member L 1  extending from the distal end to be shaped into the loop LP when the needle  30  moves backward in the predetermined direction. Hence, since the loop LP is formed in the first thread-like member L 1  extending out from the distal end of the needle  30  when the reciprocated needle  30  is retracted, the loop LP can be formed more easily than when using a needle transfer mechanism. 
     In the suturing device  10  of the present embodiment, the needle  30  is constituted by a tubule. The tubule has an opening  68  positioned at the distal end portion of the tubule. The first thread-like member L 1  passes through the tubule and is exposed to an outside of the needle  30  through the opening  68 . Accordingly, by passing the first thread-like member L 1  through both the needle  30  and the biological tissue T, the first thread-like member L 1  is exposed outside the biological tissue T at a position on the advanced side of the path K for the distal end of the needle  30 . 
     In the suturing device  10  of the present embodiment, the needle is constituted by a tubule, such as a needle  130  or needle  230 . The needle  130 / 230  has an opening  70 / 72  positioned at a peripheral wall of the needle  130 ,  230 . The first thread-like member L 1  passing through the needle  130 ,  230  and is exposed to an outside of the needle  130 ,  230  through the opening  70 ,  72 . Accordingly, by passing the first thread-like member L 1  through both the needle  130 / 230  and the biological tissue T, the first thread-like member L 1  is exposed outside the biological tissue T at a position on the advanced side of the path K for the distal end of the needle  130 / 230 . 
     While the description has been made in detail with reference to specific embodiments thereof, it would be apparent to those skilled in the art that many modifications and variations may be made thereto. 
     For example, the first thread-like member L 1  and second thread-like member L 2  in the embodiment described above may be any of various suture materials that can be tied, and preferably natural sutures formed by braiding natural plant-based or animal-based fibers, polymer sutures formed of monofilament or braided strands of synthetic fibers, metallic sutures formed of monofilament or braided metallic strands, or composite sutures formed of natural and synthetic fibers. 
     While the needle  30  is rotated only one time in the first stage for forming the knots M 1  and M 2  in the present embodiment described above in order to wrap the first thread-like member L 1  around the needle  30 , the needle  30  may instead by rotated two or more times. This action can achieve a more secure knot. 
     Similarly, while the shuttle  26  is passed only one time through the loop LP formed on the needle  30  with the first thread-like member L 1  when forming the knots M 1  and M 2  in the present embodiment described above, the shuttle  26  instead may be passed two or more times through the loop LP. This method can form an even more secure knot. 
     In the embodiment described above, the cylindrical member  12  is used as the casing having an elongated shape, but the member used as the casing may be another type of cylindrical member, such as a square cylinder member having a polygonal shaped cross section or an elliptic cylinder member having an elliptical cross section. 
     In the embodiment described above, the first operating handle  21 , second operating handle  23 , and third operating handle  25  are provided for performing manual operations to advance, retract, or rotate the first operating shaft  20 , second operating shaft  22 , and third operating shaft  24 . However, in order to perform these operations automatically, electric motors, hydraulic cylinders, and other actuators may be provided for the first operating shaft  20 , second operating shaft  22 , and third operating shaft  24 . The drive of the actuators may be controlled according to pre-stored programs to achieve the operations described in  FIGS. 34, 47, and 48 , for example. 
     In the embodiment described above, the knot M is formed after forming a plurality of stitches N, but formation of this knot M is not required. 
     When forming a stitch N in the embodiment described above, the needle  30  is advanced without rotating and retracted to form the loop LP through which the shuttle  26  is passed, but the shuttle  26  may be passed through the loop LP formed by retracting the needle  30  after the needle  30  has been advanced with rotation. In this case, the first thread-like member L 1  (bobbin thread (lower thread)) in  FIG. 52  is crossed inside the biological tissue T. This is advantageous in that each stitch N forms a knot. 
     The depression  34  in the embodiment described above is formed in the circumferential wall  32  of the cylindrical member  12  functioning as the casing and is provided with an opening  34   d  that is open in the outer wall surface of the circumferential wall  32  of the cylindrical member  12 . However, the casing may include a base part, a support column erected from the base part, and an arm part supported on the support column so as to be parallel to the base part, for example. When the needle is reciprocated along a path between the base part and the arm part, the base part and the space surrounded by the base part, support column, and arm part function as the depression. This type of depression is not provided with what was termed an opening in the embodiment. 
     In the embodiment described above, the shuttle  26  integrally configured of the holding part  62  holding the second thread-like member L 2  and the first and second hook-shaped ends  64  and  66  is threaded through the loop LP, but the shuttle  26  need not pass through the loop LP. For example, the first and second hook-shaped ends  64  and  66  may be configured separately from the holding part  62 , and the holding part  62  alone may be passed through the loop LP. 
     In the embodiment described above, the shuttle guide groove  56  having a concave cross section is provided in the shuttle guide member  36  for guiding the shuttle  26  in the longitudinal direction of the shuttle  26 , i.e., in a circumferential direction around the center axis C 1 . However, the shuttle guide groove  56  need not have a concave cross section, but may have another shape capable of guiding the shuttle  26  along its longitudinal direction. For example, the shuttle guide groove  56  may be configured of a convex guide rail, peripheral walls, or the like, as long as the guide portion can guide the shuttle  26  along its longitudinal direction. 
     Although other examples of the description will not be illustrated herein, the description can be implemented in variously modified or refined forms based on the knowledge of those skilled in the art.