Ligating apparatus - Patent Review 5702407

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a ligating apparatus for use in suture or ligation in surgical operations, and other medical procedures.

2. Description of the Related Art

In general, in surgical operations, procedures for ligating blood vessels and suturing body tissues are frequently performed. In particular, the operational work of required to form a knot is time-consuming.

Recently, surgical operations are performed with use of an endoscope ("endoscopic surgical operation"). In an endoscopic surgical operation, the operator ligates blood vessels or sutures body tissues, while viewing an endoscopic image displayed on a monitor. It is very difficult, however, to perform suture or ligation in a body cavity in which the space for movement is limited. In order to perform such operational works in a body cavity, various ligating devices have been developed.

Suture/litigation/procedures in endoscopic surgical operations are generally classified into:

(1) extracorporeal ligation,

(2) intracorporeal ligation, and

(3) suture/ligation with the use of a clip or a stapler.

The extracorporeal ligation is performed in the following manner. A thread is passed under a tissue of interest (i.e. a tissue for which the operational work is done), both ends of the thread are drawn out of the body, and a knot is formed outside the body. The knot is put into the body by means of a thread feed instrument called "knot pusher (knot driver)" and tightened. Normally this process is repeated several times. In this case, a "square knot" which is not easily loosened is formed by alternately changing the direction of crossing the thread.

In the intracorporeal ligation, a knot is formed by two forceps inserted into the body cavity. Of course, in the case of the intracorporeal ligation, the square knot which is not easily loosened should desirably be formed.

The suture/ligation technique with the use of the slip or stapler is advantageous in that the time-consuming works required for extracorporeal ligation and intracorporeal ligation can be omitted.

In the meantime, the extracorporeal ligation is troublesome since it requires frequent replacement and insertion/withdrawal of instruments. Furthermore, when the thread is pulled out of the body, the tissue located along the passage of the thread is grazed by the thread.

Although the suture/ligation technique with the use of the clip or stapler is less time-consuming, the apparatus for performing the suture/ligation is expensive. In addition, foreign matter such as a clip may be left in the body. Thus, the range of applications is limited. Depending on the kind and part of the body tissue, the suture/ligation technique with the use of the clip or stapler cannot be applied.

On the other hand, the intracorporeal ligation is free from the problems of the suture/ligation technique with the use of the clip/stapler and, unlike the extracorporeal ligation, the frequent insertion/withdrawal of instruments is not required. However, forceps must be handled in the body cavity or other limited space, while viewing a monitor which lacks in three-dimensional visual sensation. Thus, the intracorporeal ligation must be performed in an environment greatly different from that of an ordinary abdominal operation. The intracorporeal ligation thus requires a great deal of skill.

Under the situation, U.S. Pat. No. 5,281,236 and German Patent DE 3413744C2 propose ligating apparatuses for facilitating intracorporeal ligation.

Specifically, in the ligating apparatus of U.S. Pat. No. 5,281,236, a tubular catheter is movably passed through a long sheath. A curved portion forming a closed loop is provided at a distal end portion of the catheter projecting from a distal end portion of the sheath. One end portion of a thread or a suture thread passed through the catheter is projected from a distal end portion of the curved portion. In this structure, a knot is formed by passing a free-end portion of the suture thread projecting from the distal end portion of the curved portion through the loop of the curved portion. In addition, the curved portion is pulled into the sheath, thereby forcibly straightening the curved portion and making the knot fall from the distal end of the curved portion. After the knot is fallen, the free-end portion of the thread is pulled and the knot is tightened.

In the ligating apparatus of German Patent DE 3413744C2, a spiral coil portion is provided at a distal end portion of an elongated member. A suture thread is passed through the coil portion to form a knot. In addition, the elongated member is rotated, thereby rotating the coil portion and making the knot fall from a distal end of the coil portion. After the knot is fallen, a free-end portion of the thread is pulled to tighten the knot.

In both U.S. Pat. No. 5,281,236 or German Patent DE 3413744C2, however, the direction of forming the knot (i.e. the direction of the thread) is inevitably limited to one direction as determined by the direction of the curved closed loop or the direction of winding of the coil portion. As a result, the direction of the first knot is equal to that of the second knot. These of two half-knots are generally called "granny knot". The granny knot is loosened more easily than the above-mentioned square knot and is used less frequently.

Accordingly, when the ligating apparatus of U.S. Pat. No. 5,281,236 or German Patent DE 3413744C2, which can form the granny knot alone, is used, additional works are required to tighten the granny knot, for example, by increasing the number of knots.

In the case of the ligating apparatus of German Patent DE 3413744C2, moreover, it is difficult to pass the thread with a needle into the coil portion. In addition, in order to make the knot fall from the coil portion, it is necessary to rotate the elongated member by the number of times corresponding to the number of winding of the coil portion through which the thread is passed. These procedures are very time-consuming.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a general-purpose ligating apparatus suitable for ligation and suture and capable of forming a tight knot by a simple procedure.

The object of the invention can be achieved by a ligating apparatus comprising:

a first ligating member having an insertion portion to be inserted into a living body, and a holding member with a loop portion of a shape of a partially missing closed loop, said loop portion being capable of holding at least one of a ligation thread for forming a knot and a needle; and

a second ligating member having holding means capable of holding at least one of the ligation thread and the needle and capable of being passed through said loop portion, said second ligating member cooperating with said first ligating member to form a knot of the ligation thread by passing the holding means holding one end portion of the ligation thread through a knot forming loop defined by the ligation thread held by said loop portion and the loop portion.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention and, together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a partially cross-sectional perspective view schematically showing the entire structure of a thread holder of a ligating apparatus according to a first embodiment of the present invention;

FIG. 2 is a vertical cross-sectional view showing an internal structure of a thread guide member;

FIG. 3 is a side view of a distal end member body used along with a ligation thread with a needle;

FIG. 4 is a side view showing the entire structure of a forceps;

FIG. 5 is a side view of a main structure in which the forceps is inserted through a quasi-loop of the thread guide member;

FIG. 6 is a perspective view showing the state in which the thread holder is rotated clockwise with a free-end portion of the ligation thread passed behind a tubular tissue, thereby forming a quasi-loop of the ligation thread;

FIG. 7 is a perspective view showing the state in which a first half-knot of a knot is formed by pulling the free-end portion of the ligation thread with the forceps passed through the quasi-loop;

FIG. 8 is a perspective view showing the state in which the first half-knot is fallen by the thread guide member and fully tightened by crossing the thread holder and forceps, thereby completing the formation of a first half-knot of the knot;

FIG. 9 is a perspective view showing the beginning state of a work of forming a second half-knot of the knot;

FIG. 10 is a perspective view showing the state in which the forceps is passed through a second quasi-loop, with the free-end portion of the ligation thread being held;

FIG. 11 is a perspective view showing the state in which the free-end portion of the ligation thread is re-held by the forceps on the rear side of the second quasi-loop;

FIG. 12 is a perspective view showing the state in which the second half-knot is fallen from the thread guide member, while the thread holder is rotated counterclockwise in a similar manner with the formation of the first half-knot;

FIG. 13 is a perspective view showing the state in which the second half-knot is fully tightened and formed;

FIG. 14A is a plan view showing the state in which a quasi-loop is formed by the ligation thread which is guided through the thread guide member and pulled out of the cut-end of the thread guide member;

FIG. 14B is a view illustrating only the motion of the ligation thread in FIG. 14A;

FIG. 15A is a plan view showing the state in which the free-end portion of the ligation thread is passed through the quasi-loop formed by the ligation thread guided through the thread guide member and pulled out of the cut-end of the thread guide member, in a direction opposite to that illustrated in FIG. 14A;

FIG. 15B is a view illustrating only the motion of the ligation thread in FIG. 15A;

FIG. 16A illustrates a granny knot;

FIG. 16B illustrates a square knot;

FIG. 17 is a partially cross-sectional side view schematically showing the entire structure of a ligating apparatus according to a second embodiment of the invention;

FIG. 18 is a perspective view of the thread guide member;

FIG. 19 is a perspective view showing the state in which a distal-end needle portion of the thread guide member is directly stabbed into a tissue to be ligated;

FIG. 20A is a side view schematically showing the entire structure of a ligating apparatus according to a third embodiment of the invention;

FIG. 20B shows the ligating apparatus of FIG. 20A, as viewed in the direction of arrow A;

FIG. 21 is a perspective view showing the state in which a free-end portion of the ligation thread with a needle is held at a distal end portion of the holder within the body cavity;

FIG. 22 is a perspective view showing a quasi-loop formed of the thread holder and ligation thread;

FIG. 23 is a partially cross-sectional perspective view showing the structure of a main part of a ligating apparatus according to a fourth embodiment of the invention;

FIG. 24A is a partially cross-sectional perspective view showing the structure of a main part of a ligating apparatus according to a fifth embodiment of the invention;

FIG. 24B is a perspective view showing a ligation thread insertion portion of the thread guide member;

FIG. 25 is a partially cross-sectional perspective view showing the structure of a main part of a sixth embodiment of the invention;

FIG. 26 is a perspective view showing the structure of a main part of a seventh embodiment of the invention;

FIG. 27 is a perspective view showing the structure of a main part of an eighth embodiment of the invention;

FIG. 28 is a perspective view showing a main part of the ligating apparatus shown in FIG. 27, which is being used;

FIG. 29 shows the entire structure of a ligating apparatus according to a ninth embodiment of the invention;

FIG. 30 shows the entire structure of a thread hooking device of the ligating apparatus shown in FIG. 29;

FIG. 31 is an exploded view of the thread hooking device shown in FIG. 30;

FIG. 32A shows the entire structure of the forceps of the ligating apparatus shown in FIG. 29;

FIG. 32B shows a holding portion of the forceps shown in FIG. 32A;

FIG. 33 shows the state in which the forceps is projected from the arcuated portion of the thread hooking device;

FIG. 34 shows in detail the distal end member body of the thread hooking device shown in FIG. 30;

FIG. 35A is a front view showing the state in which the forceps has not yet been passed through the arcuated portion of the thread hooking device;

FIG. 35B is a cross-sectional side view showing the state in FIG. 35A;

FIG. 36A is a front view showing the state in the forceps is being passed through the arcuated portion of the thread hooking device;

FIG. 36B is a cross-sectional side view showing the state in FIG. 36A;

FIG. 37A is a front view showing the state in which the distal end portion of the forceps is about to be passed through the quasi-loop;

FIG. 37B shows a quasi-loop formed by the arcuated portion and the suture thread;

FIG. 38 is an enlarged view of a distal end portion of an inner pipe of the thread hooking device shown in FIG. 30;

FIG. 39 is a distal-end side cross-sectional view in the state in which the distal end member body is connected to the inner pipe;

FIG. 40 is a proximal-end side cross-sectional view in the state in which outer and inner pipes are connected;

FIG. 41 is a cross-sectional view of a thread fixing portion in a thread fixing release state of the thread hooking device shown in FIG. 30;

FIG. 42 is a cross-sectional view of a thread fixing portion in a thread fixing state of the thread hooking device shown in FIG. 30;

FIG. 43A and FIG. 43B show a first step of forming a first half-knot;

FIG. 44A and FIG. 44B show a second step of forming the first half-knot;

FIG. 45A and FIG. 45B show a first step of forming a second half-knot;

FIG. 46A and FIG. 46B show a second step of forming the second half-knot;

FIG. 47 shows the state in which a tubular tissue is exfoliated by a forceps;

FIG. 48 shows the state in which the free-end portion of the ligation thread is held by another forceps;

FIG. 49 shows the state in which a quasi-loop is formed, following the state shown in FIG. 48;

FIG. 50 shows the state in which the ligation thread is passed through the tissue and the free-end portion of the ligation thread is held by the forceps;

FIG. 51 shows the state in which the free end portion of the ligation thread held by the forceps is passed through the quasi-loop, thereby to form a first half-knot of a knot;

FIG. 52 shows the state in which the first half-knot is fallen from a knot forming member and the formation of the first half-knot is completed;

FIG. 53 shows the state in which the free-end portion of the ligation thread, while being held by the forceps, is passed through the quasi-loop, following the state shown in FIG. 52;

FIG. 54 shows the state in which a second half-knot is formed;

FIG. 55 shows the state in which the second half-knot is fallen from the knot forming member and the formation of the second half-knot is completed;

FIG. 56 shows the state in which the first half-knot and second half-knot are tightened to form a square knot;

FIG. 57 shows a distal end portion of a ligating apparatus according to a tenth embodiment of the present invention;

FIG. 58A and FIG. 58B show a distal end portion of a ligating apparatus according to an eleventh embodiment of the invention;

FIG. 59 shows a distal end portion of a ligating apparatus according to a twelfth embodiment of the present invention;

FIG. 60 shows the state in which the ligation thread is passed behind the tubular tissue by using the ligating apparatus shown in FIG. 59;

FIG. 61 shows the entire structure of a ligating apparatus according to a 13th embodiment of the invention;

FIG. 62 shows an operating state of the ligating apparatus shown in FIG. 61;

FIG. 63A shows a distal end portion of a ligating apparatus according to a 14th embodiment of the present invention;

FIG. 63B shows the state in which a distal end portion of a knot forming member is stabbed into the body tissue by using the ligating apparatus shown in FIG. 63A;

FIG. 64 shows a distal end portion of a ligating apparatus according to a 15th embodiment of the present invention;

FIG. 65 shows a distal end portion of a ligating apparatus according to a 16th embodiment of the present invention;

FIG. 66 is a perspective view of a forceps apparatus according to a 17th embodiment of the invention;

FIG. 67 is a cross-sectional view of the entire forceps apparatus shown in FIG. 66;

FIG. 68A is a cross-sectional view taken along line 68A--68A in FIG. 67;

FIG. 68B is a plan view, taken in a direction of arrow 68B in FIG. 67;

FIG. 69 is a perspective view of a distal end portion of the forceps apparatus shown in FIG. 66;

FIG. 70A and FIG. 70B illustrate an operation in which a curved needle is held by the forceps apparatus of FIG. 66;

FIG. 71A and FIG. 71B illustrate an operation in which a curved needle is held by the forceps apparatus of FIG. 66;

FIG. 72A and FIG. 72B illustrate an operation in which a knot is formed by using the forceps apparatus shown in FIG. 66;

FIG. 73A to FIG. 73C illustrate an operation in which a knot is formed by using the forceps apparatus shown in FIG. 66;

FIG. 74A to FIG. 74D illustrate an operation in which a knot is formed by using the forceps apparatus shown in FIG. 66;

FIG. 75A to FIG. 75D illustrate another method of forming a second half-knot;

FIG. 76 is a vertical cross-sectional view of a forceps apparatus according to a 18th embodiment of the invention;

FIG. 77 shows the forceps apparatus of FIG. 76, as viewed in the direction of arrow 77 in FIG. 76;

FIG. 78A is a view taken in the direction of arrow D in FIG. 78B;

FIG. 78B is a side view of first and second distal end members;

FIG. 79 is a perspective view of a distal end portion of a forceps apparatus according to a 19th embodiment of the invention;

FIG. 80 is a perspective view of a forceps apparatus with first and second rectangular-parallelepipedic distal end members;

FIG. 81 is a perspective view of a forceps apparatus with first and second disk-like distal end members;

FIG. 82 illustrates a general method of forming a knot by means of the forceps apparatus;

FIG. 83 is a perspective view of a ligating apparatus according to a 20th embodiment of the invention; and

FIG. 84 is a perspective view of a ligating apparatus according to a 21st embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 through FIGS. 16A and 16B show a first embodiment of the invention. As is shown in FIG. 1, a thread holder (first ligating member) 1 comprises an insertion portion 2 to be inserted into a body cavity, and a handle portion 3 coupled to a proximal end portion of the insertion portion 2. The insertion portion 2 comprises an elongated rod-like shaft portion 4, and a distal end member 5 coupled to a distal end portion of the shaft portion 4. A threaded hole 6 is formed in the distal end portion of the shaft portion 4. A male thread portion 7 is provided on a proximal end portion of the distal end member 5. The male thread portion 7 is engaged with the threaded hole 6. Thus, the distal end member 5 can be detachably attached to the shaft portion 4.

The distal end member 5 comprises a substantially cylindrical distal end member body 8 and a thread guide member 9 projecting from a distal end portion of the distal end member body 8. The outer peripheral surface of the distal end portion of the distal end member body 8 is beveled, thereby forming an inclined surface 10 for preventing the visual field from being obstructed. As is shown in FIG. 2, an axially extending fixing hole 11 for fixing the thread guide member 9 is formed in the distal end portion of the distal end member body 8.

The thread guide member 9 is formed of a hollow tubular member of hard material. As is shown in FIG. 2, a first suture thread passage 13 for passing a suture thread 12 is formed in the thread guide member 9. The inside diameter of the first suture thread passage 13 is greater than the outside diameter of the suture thread 12 inserted in the first suture thread passage 13, so that the suture thread 12 can be inserted through the passage 13. The thread guide member 9 comprises a straight portion 9a extending in parallel to the axis of the insertion portion 2, and a substantially C-shaped arcuated portion 9b disposed at a distal end portion of the straight portion 9a. Specifically, the arcuated portion 9b has a partially missing or imperfect loop shape. A proximal end portion of the straight portion 9a of the thread guide member 9 is inserted and fixed in the fixing hole 11 in the distal end member body 8. A thread release port 13a for releasing the suture thread 12 to the outside is formed at the end portion of the imperfect loop of the thread guide member 9, that is, a distal end portion 9b of the arcuated portion 9b. The inside diameter and central angle .phi. of the arcuated portion 9b of the thread guide member 9 are determined so that a forceps 14 (described later) can be passed through the arcuated portion 9b. In the present embodiment, as shown in FIG. 1, the central angle .phi. of the arcuated portion 9b is set at about 270.degree..

A second suture thread passage 15 is formed in the distal end member body 8. One end portion of the second suture thread passage 15 communicates with the first suture thread passage 13 of the thread guide member 9, and the other end portion of the passage 15 communicates with a counterbore 16 opening to the outer peripheral surface of the distal end member body 8. The second suture thread passage 15 has the same inside diameter as the first suture thread passage 13 of the thread guide member 9.

The suture thread 12 used in the present embodiment is inserted into the first suture thread passage of the thread guide member 9 from the thread release port 13a, is passed through the second thread passage 15, and is drawn out of the counterbore 16 by a suitable length. A knot 17 is formed at the end portion of the suture thread 12 drawn out of the counterbore 16. The knot 17 is sunk and set in the counterbore 16. The counterbore 16 is slightly greater in size than the knot 17 of the suture thread 12. The diameter of the second suture thread passage 15 is set so as to prevent passage of the knot 17. Accordingly, even if a free-end portion 18 of the suture thread 12, located opposite to the knot 17, is pulled, the suture thread 12 is not removed from the distal end member body 8.

FIG. 4 shows the forceps (second ligating member) 14 to be used in combination with the thread holder 1. The forceps 14 has the same structure as the one generally used in endoscopic surgical operations. Specifically, the forceps 14 comprises an insertion portion 19 to be inserted into the body cavity, and a handle unit 20 connected to a proximal end portion of the insertion portion 19. The handle unit 20 comprises a fixed handle 21 and a movable handle 23 rotatably coupled to the fixed handle 21 by means of a coupling pin 22. A treatment unit (holding or manipulating device) 24 is provided at a distal end portion of the insertion portion 19. The treatment unit 24 comprises a pair of holding portions 24a and 24b. The insertion portion 19 comprises a sheath 25 and an operating shaft 26 provided inside the sheath 25. A proximal end portion of the operating shaft 26 is coupled to the movable handle 23, and a distal end portion of the operating shaft 26 is coupled to the holding portions 24a and 24b by means of a opening/closing mechanism constituted by, e.g. a link mechanism. Accordingly, if the handle unit 20 is operated, the operating shaft 26 is moved forward and backward along the axis thereof, thereby opening/closing the holding portions 24a and 24b.

As is shown in FIG. 2, the arcuated portion 9b of the thread guide member 9 is inclined at an angle .alpha. with respect to the straight portion 9a. As is shown in FIG. 5, in the state in which the treatment unit 24 of the forceps 14 is inserted through the arc of the arcuated portion 9b, the angle .beta. between a center axis O.sub.1 of the thread holder 1 and a center axis O.sub.2 of the insertion portion 19 of the forceps 14 and the inclination angle .alpha. a should desirably have the following relationship:

.alpha.=90.degree.-.beta.

In the state of normal use, the inclination angle .alpha. of the arcuated portion 9b should desirably be between 30.degree. and 60.degree..

The operation of the ligating apparatus comprising the thread holder 1 and forceps 14 will now be described. At first, a method of forming a knot of the suture thread 12 by using the thread holder 1 will be described. As is shown in FIG. 14A, the free end portion 18 of the suture thread 12 projecting from the thread release port 13a of the arcuated portion 9b of the thread guide member 9 is pulled to the cut-end side of the loop of the arcuated portion 9b, while being held, for example, between the holding portions 24a and 24b of the treatment unit 24 of the forceps 14. Thus, a quasi-loop 28 is formed by the suture thread 12 and arcuated portion 9b. From this state, the treatment unit 24 holding the free end portion 18 of the suture thread 12 is passed through the quasi-loop 28, as indicated by the arrow in FIG. 14B, thereby provisionally forming a first half-knot of the suture thread 12. Then, the provisionally formed first half-knot is fallen from the "cut-out portion" of the arcuated portion 9b (i.e. the gap between the proximal end and distal end of the arcuated portion 9b) of the thread guide member 9 and tightened, thereby forming the first half-knot 29, as shown in FIGS. 16A and 16B.

Subsequently, a second half-knot is formed by passing the thread in a direction opposite to that in forming the first half-knot 29. Thus, a secure square knot 32 (see FIG. 16B) is formed. In order to form the square knot, the free end portion 18 of the suture thread 12 must be passed through the quasi-loop 28 in the opposite direction, as shown in FIGS. 15A and 15B. Specifically, the suture thread 12 is looped on the rear side of the thread guide member 9 and the free end portion 18 of the suture thread 12 is passed through the quasi-loop 28 formed by the arcuated portion 9b and arcuately extended suture thread 12 towards the rear side of the thread guide member 9. Thereby, the second half-knot 31b is formed and the square knot 32 is formed.

If the thread guide member 9 has a loop shape of more than a single winding, the direction of winding is inevitably determined. Thus, only a granny knot (see FIG. 16A) having the second half-knot 31a and first half-knot 29 formed in the same direction is obtained. In order to obtain the square knot 32, it is necessary to form the thread guide member 9 in the arcuated shape (.i.e. a part of a loop is missing) and to make the direction of winding of the suture thread 12 selectable at the time of use. If this condition is met, the half-knot formed at the arcuated portion 9b of the thread guide member 9 can be fallen from the missing portion of the loop.

A description will now be given of the case where a tubular tissue (blood vessel, etc.) is ligated ("intracorporeal ligation") by the suture thread 12 by using the ligating apparatus comprising the thread holder 1 and forceps 14.

The insertion portion 2 of the thread holder 1 is inserted into the patient's body under observation by an endoscope (not shown). The distal end member 5 of the insertion portion 2 is approached to the tubular tissue of interest. As is shown in FIG. 6, after tubular tissue 27 is exfoliated, the free end portion 18 of the suture thread 12 is passed behind the tubular tissue 27. In this state, the insertion portion 2 of the thread holder 1 is rotated clockwise. Thereby, the suture thread 12 is extended from the thread release port 13a of the arcuated portion 9b of thread guide member 9 towards the missing portion of the loop. In this state, as shown in FIG. 6, a quasi-loop 28 is formed by the suture thread 12 and arcuated portion 9b. At this time, the suture thread 12 is brought to the front side of the thread guide member 9.

Then, the treatment unit 24 of the forceps 14 is passed through the quasi-loop 28, and the free end portion 18 of the suture thread 12 is held by the holding portions 24a and 24b of the treatment unit 24. Subsequently, the treatment unit 24 of the forceps 14, which holds the suture thread 12, is pulled out of the quasi-loop 28. Thus, as shown in FIG. 7, the free end portion of the suture thread 12 is pulled out of the quasi-loop 28 and a first half-knot is provisionally formed. In this state, the thread holder 1 is rotated counterclockwise, as indicated by the arrow in FIG. 7, thereby falling the provisionally formed first half-knot from the thread guide member 9. Then, as shown in FIG. 8, the thread holder 1 and forceps 14 are pushed forward in mutually crossing directions. Thus, the suture thread 12 is fully tightened and the first half-knot 29 is formed.

After the first half-knot 29 is formed, the free end portion 18 of the suture thread 12 is held by means of the treatment unit 24 and a second quasi-loop 30 is formed of the suture thread 12 and the arcuated portion 9b of the thread guide member 9, as shown in FIG. 9. At this time, attention should be paid so that the suture thread 12 is located behind the thread guide member 9. Then, as shown in FIG. 10, the treatment unit 24 holding the suture thread 12 is passed through the second quasi-loop 30 and the holding portions 24a and 24b of the treatment unit 24 are opened to release the free end portion 18 of the suture thread 12 from the treatment unit 24. Subsequently, the treatment unit 24 of the forceps 14 is pulled out of the quasi-loop 30 and, as shown in FIG. 11, the free end portion 18 of the suture thread 12 is held once again by the treatment unit 24 on the rear side of the second quasi-loop 30. Thereafter, like the formation of the first half-knot 29, the thread holder 1 is rotated counterclockwise, as indicated by the arrow in FIG. 12, and a provisionally formed second half-knot is fallen from the thread guide member 9. The thread holder 1 and forceps 14 are pulled, as indicated by the arrows in FIG. 13, and the provisionally formed second half-knot is tightened. Thus, the second half-knot 31b is formed.

The thus formed knot of the suture thread 12 is called a square knot having high ligative strength, which comprises the first half-knot 29 and second half-knot 31b formed in reverse directions, as shown in FIG. 16B. If the above procedure is repeated on an as-needed basis, a securer knot can be obtained. The above-described ligative procedure is applicable to suture of tissues. In the case of the suture, a suture needle 34 is attached to the free end portion 18 of the suture thread 12, as shown in FIG. 3.

In the present embodiment, the arcuated portion 9b of the thread guide member 9 is wound clockwise, as viewed from the front side, and the thread guide member 9 is approached from the left side of the tissue. Needless to say, however, the same operation and advantage can be obtained even if the direction of winding of the arcuated portion 9b of thread guide member 9 and the direction of approach to the tissue are different from those in the present embodiment. When the ligating apparatus of the present embodiment is used in an endoscopic surgical operation, it is desirable that the outside diameter of the arcuated portion 9b of the thread guide member 9 be less than that of the insertion portion 2.

As has been described above, the ligating apparatus of the present embodiment, as compared to the conventional ligating apparatus, has a simpler structure, is easier to handle, and makes it possible to form the secure square knot 32. In addition, in the ligating apparatus of the present embodiment, as shown in FIG. 2, the arcuated portion 9b of the thread guide member 9 of thread holder 1 is bent at an angle .alpha. with respect to the straight portion 9a. Thus, the treatment unit 24 of the forceps 14 can be easily passed through the quasi-loop formed by extending the suture thread 12 from the arcuated portion 9b of the thread guide member 9 toward the missing portion of the loop. Furthermore, the provisional half-knot formed on the arcuated portion 9b of the thread guide member 9 can be easily fallen from the arcuated portion 9b.

FIGS. 17 to 19 show a second embodiment of the invention. In this embodiment, as shown in FIG. 18, a sharp needle portion 41 is formed at a distal end portion of the arcuated portion 9b of thread guide member 9. Thus, as shown in FIG. 19, the distal end of the arcuated portion 9b can be smoothly stabbed into a tissue 42 of interest by virtue of the sharp needle portion 41. A thread release port 13a is formed at an outer peripheral portion of the arcuated portion 9b near the needle portion 41. Thus, the suture thread 12 extended from the thread release port 13a is not cut by the needle portion 41.

In addition, as shown in FIG. 17, the suture thread 12 is inserted into a first suture thread passage 13 of the thread guide member 9 from the thread release port 13a and guided out from a counterbore 16 in the outer peripheral surface of the distal end member body 8. The suture thread 12 is then guided to the handle portion 3 along the insertion portion 2. The handle portion 3 is provided with a thread engaging portion 43 for disengageably engaging the suture thread 12. The thread engaging portion 43 has an operating knob 44 provided on the handle portion 3. An insertion port 45, through which the suture thread 12 can pass, is formed in a front end portion of the operating knob 44. An abutment portion 46 extending obliquely downward from the front end of the insertion port 45 is provided on a lower surface of the operating knob 44. A slide-guide projection 47 is provided at a rear end portion of the operating knob 44. A recess-like guide groove 48 extending in parallel to the axis of the handle portion 3 is formed in the outer peripheral surface of the handle portion 3. The projection 47 of the operating knob 44 is inserted in the guide groove 48, and a coil spring 49 for urging the projection 47 to the rear side of the guide groove 48 is mounted in the guide groove 48. A distal-end edge portion of the handle portion 3 is provided with an abutment surface 50 upon which the abutment portion 46 of the operating knob 44 abuts.

When the suture thread 12 is engaged with the thread engaging portion 43 having the above structure, the operating knob 44 is pushed forward against the urging force of the coil spring 49 and the insertion port 45 of the operating knob 44 is located in front of the handle portion 3. In this state, the suture thread 12 is passed through the insertion port 45 and the operating force of the handle portion 3 is released. The operating knob 44 is moved backward by the urging force of the coil spring 49 and the abutment portion 46 of the operating knob 44 abuts on the abutment surface 50 of the handle portion 3. Thereby, the suture thread 12 is engaged between the abutment portion 46 of the operating knob 44 and the abutment surface 50 of the handle portion 3. Inversely, the engagement of the suture thread 12 can be released by sliding the operating knob 44 forward against the urging force of the coil spring 49. In the state in which the engagement of the suture thread 12 is released, the suture thread 12 is not separated from the abutment surface 50 of the handle portion 3. Thus, the suture thread 12 of necessary length can be pulled out of the thread release port 13a of the thread guide member 9 on an as-needed basis and then the suture thread 12 can be engaged once again. The ligating apparatus of the second embodiment has the same structure as the ligating apparatus of the first embodiment, except for the above-described characterizing structural feature.

The operation of the ligating apparatus of the second embodiment will now be described. At first, the suture thread 12 is pulled out of the thread release port 13a of the thread holder 1 by about 1 cm to 2 cm. In this state, the sharp needle portion 41 of the arcuated portion 9b is directly stabbed into the tiss