Abstract:
Tissue suturing instruments and methods of using same are provided. The tissue suturing instruments are designed and configured for suturing tissue grasped thereby to soft tissue as well as to hard tissue.

Description:
RELATED PATENT APPLICATIONS  
       [0001]     This is a continuation of U.S. patent application Ser. No. 09/994,882 filed 28 Nov. 2001, which is a Continuation-in-Part of U.S. patent application Ser. No. 09/722,712, filed 28 Nov. 2000, now U.S. Pat. No. 6,511,487. 
     
    
     FIELD AND BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to suturing instruments useful in surgery, and also to a method of applying a suture to tissue during surgery.  
         [0003]     Many surgical procedures are presently being performed via an endoscope in order to minimize the size of the incisions and the trauma to the patient. In such procedures, the surgical instrument is generally introduced through a cannula or passageway in the endoscope while the surgeon views the surgical site through another passageway in the endoscope. A number of forceps-type suturing instruments have been designed for introduction through a cannula used in endoscopic procedures. One such forceps-type suturing instrument is disclosed in U.S. Pat. Nos. 5,730,747 and 6,051,006. The known suturing instruments of this type, however, are generally of relatively complicated construction and/or are useful only with respect to needled sutures.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0004]     An object of the present invention is to provide a suturing instrument of relatively simple construction and which can be used with unneedled sutures, i.e., suture threads per se, i.e., without a puncturer being attached to the suture.  
         [0005]     Another object of the invention is to provide a suturing instrument particularly useful as a forceps type instrument for introduction through a cannula used in endoscopic procedures. A further object of the invention is to provide a novel method of applying a suture to tissue.  
         [0006]     According to one aspect of the present invention, there is provided a suturing instrument comprising: a jaw formed with an opening therethrough; a puncturer pivotally mounted from an open position on one side of the jaw to a closed position through the opening to the opposite side of the jaw, the puncturer being constructed to receive a suture in the open position of the puncturer and to move a portion of the suture through the jaw opening to the opposite side of the jaw when actuated to the closed position of the puncturer; and a crochet head for engaging the portion of the suture at the opposite side of the jaw opening and for clamping the suture to the jaw thereby permitting the puncturer to return to its open position while disengaged from the suture.  
         [0007]     According to another aspect of the present invention, there is provided a method of applying a suture to tissue, comprising: pivotally mounting a puncturer with respect to a jaw having an opening therethrough such that the puncturer is pivotal from an open position on one side of the jaw through the opening in the jaw to a closed position on the opposite side of the jaw; applying a suture to the puncturer when the puncturer is in its open position on one side of the jaw; locating the jaw on one side and the pivotal puncturer on the opposite side, of the tissue to be sutured; pivoting the puncturer towards the jaw to pierce the tissue and to pass the puncturer therethrough and through the opening in the jaw to the closed position of the puncturer on the opposite side of the jaw, and thereby to bring a portion of the suture with the puncturer to the opposite side of the jaw; clamping to the jaw the portion of the suture at the opposite side of the jaw; and pivoting the puncturer back to its open position while the suture is clamped to the jaw.  
         [0008]     According to a further aspect of the present invention, there is provided a tissue suturing instrument comprising a tissue grasping mechanism designed and configured for grasping a tissue and for positioning a suture on a first side of tissue; and a crochet head designed and configured for piercing through the tissue from a second side thereof and engaging the suture, thereby enabling drawing the suture through the tissue.  
         [0009]     According to features in a described embodiment of the invention, the crochet head is slidably mounted at the opposite side of the jaw and is movable through a forward stoke from a retracted position at the proximal end of the jaw to an extended position at the distal end of the jaw, and through a return stroke back to the retracted position. The crochet head has a shaped surface effective to engage the portion of the suture at the opposite side of the jaw during the forward stroke of the crochet head, and to clamp same to the jaw during the return stroke of the crochet head.  
         [0010]     According to further features in the described embodiment, the jaw is part of a frame assembly including a proximal section formed with a first handle, and a distal section carrying the jaw; and the puncturer is part of a puncturer assembly including a proximal section formed with a second handle pivotally mounted with respect to the first handle, a distal section including the pivotally mounted puncturer, and a coupling between the second handle and puncturer for pivoting the puncturer from the open position to the closed position upon pivoting the second handle with respect to the first handle. Similarly, the crochet head is part of a crochet head assembly including a proximal section formed with a third handle pivotally mounted with respect to the first handle, a distal section carrying the crochet head, and a coupling for moving the crochet head through its forward and return strokes by the pivoting of the third handle with respect to the first handle.  
         [0011]     According to further features in the described embodiment, the instrument comprises a frame assembly including a proximal section formed with a first handle and a distal section carrying the tissue grasping mechanism and the crochet head, the sections connected by an elongated shank.  
         [0012]     According to further features in the described embodiment, the first handle is disposed substantially perpendicular to the elongated shank.  
         [0013]     According to further features in the described embodiment, the tissue grasping mechanism comprises at least two grasping members including a static member disposed rigidly upon the elongated shank and a movable member pivotally movable relative to the static member.  
         [0014]     According to further features in the described embodiment, the movable member is pivotally mounted to the static member.  
         [0015]     According to further features in the described embodiment, the static member is formed with a face facing the movable member having a ribbed surface for firmly grasping the tissue.  
         [0016]     According to further features in the described embodiment, the static member is formed with a guide member disposed thereon for guiding the crochet head.  
         [0017]     According to further features in the described embodiment, the movable member is for carrying the suture, whereas a distal end of the movable member is formed with an opening therethrough alignable with the guide member for guiding the crochet head to engage the suture when the suture is positioned on the first side of the tissue.  
         [0018]     According to further features in the described embodiment, the tissue grasping mechanism is part of a tissue grasping assembly including a proximal section formed with a second handle pivotally mounted relative to the first handle, a distal section carrying the static member and the movable member, and a coupling between the second handle and the movable member for pivoting the movable member upon pivoting the second handle.  
         [0019]     According to further features in the described embodiment, the coupling includes a rod extending through the elongated shank of the frame assembly.  
         [0020]     According to further features in the described embodiment, the crochet head is part of a crochet head assembly including a proximal section formed with a third handle pivotally mounted relative to the first handle, a distal section carrying the crochet head, and a coupling between the third handle and the crochet head for moving the crochet head upon pivoting the third handle.  
         [0021]     According to further features in the described embodiment, the coupling includes a slide slidable with respect to the elongated shank of the frame assembly, the slide being aligned with the guide member.  
         [0022]     According to further features in the described embodiment, the crochet head is slidably mounted in proximity to the tissue grasping mechanism and is movable through a forward stroke from a retracted position at a proximal end of the tissue grasping mechanism to an extended position beyond a distal end of the tissue grasping mechanism, and through a return stroke back to the retracted position; the crochet head having a point for piercing the tissue during the forward stroke, a shaped surface for engaging the suture, and a hook formation for drawing the suture through the tissue during the return stroke.  
         [0023]     According to further features in the described embodiment, the third handle is spring-biased to the retracted position.  
         [0024]     As will be described more particularly below, the foregoing features enable suturing instruments to be constructed with a relatively few simple parts and to be used with unneedled sutures.  
         [0025]     Further features and advantages of the invention will be apparent from the description below.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]     The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.  
         [0027]     In the drawings:  
         [0028]      FIG. 1  is a side view illustrating a preferred embodiment of a suturing instrument constructed in accordance with the present invention;  
         [0029]      FIG. 2  is an enlarged bottom view of the distal end of the suturing instrument of  FIG. 1 , illustrating the puncturer in its open position for receiving a suture;  
         [0030]      FIG. 3  is an enlarged side view of the distal end of the suturing instrument of  FIG. 1  with the crochet head in its extended position;  
         [0031]      FIG. 4  is a perspective view of the distal end of an alternative embodiment of a suturing instrument constructed in accordance with the present invention, illustrating the grasping mechanism in its closed position;  
         [0032]      FIG. 5  is a perspective view of the distal end of the suturing instrument of  FIG. 4  illustrating the grasping mechanism in its open position; and  
         [0033]      FIG. 6  is and end view of the movable grasping member of the suturing instrument of  FIG. 4 .  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]     The present invention is of suturing devices and methods which can be used to efficiently insert a suture in tissue during surgery. Specifically, the present invention can be used in minimally invasive, endoscope, laparoscope or arthroscope assisted surgeries.  
         [0035]     The principles and operation of a device and method according to the present invention may be better understood with reference to the drawings and accompanying descriptions.  
         [0036]     Before explaining the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following descriptions or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.  
         [0037]      FIG. 1 , illustrates one configuration of a suturing device/instrument according to the present invention.  
         [0038]     The suturing instrument illustrated in  FIG. 1  is of the forceps type particularly useful by applying it through a cannula used in endoscopic procedures in order to suture tissue at the surgical site.  
         [0039]     This configuration of the suturing instrument is composed of three main assemblies: 
        (1) a frame assembly, generally designated  2 , including a first handle  2  at one end (hereinafter called the proximal end), fixed substantially perpendicularly to an elongated shank  21  ( FIG. 2 );     (2) a puncturer assembly, generally designated  3 , including a second handle  30  at the proximal end of the instrument, pivotally mounted to the frame assembly  2  and coupled to a puncturer  31  ( FIG. 2 ) pivotally mounted at the distal end of the elongated shank  21 ; and 
            (3) a crochet head assembly, generally designated  4 , including a third handle  40  also pivotally mounted to the frame assembly  2  and coupled to a slidable crochet head  41  at the distal end of the elongated shank  21 .    
               
 
         [0043]     As will be described more particularly below, the suture, shown at  5  in  FIG. 2 , is loaded onto the puncturer  31  when in its open position as illustrated in  FIG. 2 .  
         [0044]     With respect to the frame assembly  2 , the proximal end of the elongated shank  21  is fixed within a perpendicular extension  22  at the upper end of handle  20 . The distal end of the elongated shank  21  carries a fixed jaw  23  formed with a pair of legs  23   a ,  23   b  parallel to the axis of the elongated shank  21  and spaced from each other to define a space  23   c . As shown particularly in  FIG. 2 , the inner surface of jaw  23  facing the pivotal puncturer  31  is ribbed as shown at  23   d  in order to firmly grasp the tissue to be sutured between it and the pivotal puncturer, as will be described below.  
         [0045]     The distal end of the elongated shank  21  further includes a U-shaped member  24  serving as a guide for a part of the crochet head assembly  4 , as will be described below. In addition, extension  22  of handle  20  is formed with a slot  25  ( FIG. 1 ) at the proximal end of the elongated shank  21 , for accommodating a coupling element of the crochet head assembly  4  as will also be described below. Further, the upper end of handle  20  of the frame assembly  2  includes an abutment  26  serving as a stop for limiting the pivotal movement of handle  30  of the puncturer assembly  3 .  
         [0046]     With respect to the puncturer assembly  3 , handle  30  of that assembly is pivotally mounted at  32  to the upper end of handle  20  of the frame assembly  2 . As shown particularly in  FIG. 2 , puncturer  31  pivotally mounted at the distal end of the elongated shank  21 , is formed with a hole  31   a  for receiving the suture  5 , and with a pointed tip  31   b  for piercing the tissue clamped between it and the ribbed surface  23   d  of the fixed jaw  23 .  
         [0047]     Puncturer  31  is pivotally mounted to the distal end of the elongated shank  21  by an arm  33  carrying the puncturer  31  at one end, and pivotally mounted at its opposite end  34  to the elongated shank  21 . Arm  33  is coupled to the upper end of handle  30  of the puncturer assembly  3  by a rod  35  ( FIG. 1 ) passing through, or alongside of, the elongated shank  21 . The arrangement is such that pivoting handle  30  away from handle  20  pivots puncturer  31  to its open position illustrated in  FIG. 2  for receiving the suture  5 , and pivoting handle  30  towards handle  20  moves puncturer  31  through the opening  23   c  in the jaw  23  to pierce the tissue clamped between the puncturer and the jaw, and to bring the suture  5  to the opposite side of the jaw. Handle  30  is formed on its inner face with an abutment  36  engagable with abutment  26  of handle  20  to limit the latter pivotal movement of handle  30 .  
         [0048]     With respect to the crochet head assembly  4 , its handle  40  is pivotally mounted at  42  to the upper end of handle  20  of the frame assembly  2 . Preferably, this pivotal mounting includes a piano spring (not shown) to bias the handle  40  to the position illustrated in  FIG. 1 , which is the retracted position of the crochet head  41 .  
         [0049]     The crochet head  41  is carried at the distal end of a slide  43  extending along one side of the elongated shank  21 . The proximal end of slide  43  is coupled by a pin  44  ( FIG. 1 ) to the upper end of handle  40 . Pin  44  is movable within slot  25  in the extension  22  at the upper end of handle  20  to limit the pivotal movements of handle  40  with respect to handle  20 . As will be described below, handle  40  may be pivoted with respect to handle  20  to move slide  43 , and the crochet  41  carried at the distal end of the slide, through forward and return strokes parallel to the longitudinal axis of the elongated shank  21 . The forward and return movements of the slide  43  are guided by the U-shaped member  24  at the distal end of the elongated shank.  
         [0050]     The structure of the crochet head  41  is more particularly illustrated in  FIG. 3 . It includes a tapered nose  41   a  at one end for engaging the suture  5  during the forward movement of the crochet head, and a hook formation at the opposite end for receiving the suture and for clamping it to the jaw  23  during the return movement of the crochet head. The crochet head is further formed with an axial slot  41 c to accommodate the pointed tip  31   b  of the puncturer  31  when the puncturer is pivoted to its closed position and the crochet has been moved to its most forward position.  
         [0051]     The illustrated suturing instrument may be used in the following manner.  
         [0052]     First, handle  30  is pivoted away from handle  20  so as to pivot the puncturer  31  to its open position as shown in  FIG. 2 , to enable the suture  5  to be loaded thereon by passing the suture through opening  31   a  of the puncturer.  
         [0053]     Handle  30  may then be pivoted towards handle  20  to move the puncturer  31 , together with the portion of the suture carried thereby, to the closed position of the puncturer, i.e., through opening  23   c  of jaw  23 . This enables the distal portion of the instrument to be inserted through the cannula (not shown) of the endoscope. After the distal portion of the instrument has passed through the cannula and is located in the surgical site, handle  30  may be pivoted away from handle  20  to return the puncturer to its open position, as shown in  FIG. 2 , preparatory to its use for suturing tissue. In this condition of the instrument, handle  40  is in the position shown in  FIG. 1 , such that the crochet head  41  actuated by the handle is in its retracted position on the proximal side of jaw  23 .  
         [0054]     The surgeon may then manipulate the instrument with the puncturer  31  in its open position to locate the puncturer on one side of the tissue to be sutured, and to locate the jaw  23  on the opposite side of the tissue to be sutured. The surgeon then moves handle  30  towards handle  20 , which thereby, by virtue of the coupling rod  35 , pivots puncturer  31  towards jaw  23  and then through the opening  23   c  in the jaw, to thereby pierce the tissue and to bring the portion of suture  5  within the needle hole  31   a  to the opposite side of the jaw. While the puncturer is in its closed position, handle  40  is then pivoted clockwise to move the crochet head  41 , coupled to the handle by slide  43 , through a forward stroke parallel to the elongated shank  21  from the proximal side of the jaw  23  to the distal side thereof, and then releases handle  40  to permit its spring bias to return the crochet head through a return stroke back to its initial position at the proximal side of the jaw.  
         [0055]     During the movement of the crochet head in the forward stroke, its nose  41   a  engages the suture that has been passed through opening  23   c  in jaw  23 , and guides the suture to the hook portion  41   b  of the crochet head, such that when the crochet head returns during the return stroke back to its initial position, the hook portion  41   b  of the crochet head clamps the suture to the jaw  23 . Handle  30  may then be moved away from handle  20  to pivot the puncturer  31  to its open position, and thereby to release the tissue. The instrument may then be used for applying another suture to another portion of the tissue by repeating the foregoing steps.  
         [0056]     Reference is now made to  FIGS. 4-6  which illustrate an alternative embodiment of the suturing instrument of the present invention which is referred to hereinunder as suturing instrument  45 .  
         [0057]     Suturing instrument  45  includes a frame assembly (not shown) which is substantially identical to frame assembly  2  shown in  FIG. 1  and as such includes a first handle at the proximal end, fixed substantially perpendicularly to an elongated shank; a perpendicular extension at the upper end of the first handle which is formed with a slot for accommodating a coupling element; a second handle pivotally mounted to the upper end of the first handle; a coupling element for coupling the second handle to the tissue grasping elements; a first abutment at the upper end of the first handle serving as a stop for limiting the pivotal movement of the second handle; a second abutment at the upper end of the second handle engagable with the first abutment; a third handle pivotally mounted to the upper end of the first handle, preferably including a piano spring to bias the third handle to the position illustrated in  FIG. 1 ; and a pin movable within a slot which couples a coupling slide to the upper end of the third handle. These components of suturing instrument  45  function similarly to those described hereinabove with respect to  FIG. 1 , and as such are numerically referenced hereinunder, in parentheses, with numbers used to identify similar components shown in  FIG. 1 .  
         [0058]     In addition, suturing instrument  45  further includes a suturing head  70  which includes a separate tissue grasping mechanism and a piercing mechanism, exemplary configurations of which are further described hereinbelow with reference to  FIGS. 4 and 5 .  
         [0059]     The function of suturing instrument  45  is distinguished from the function of the formerly described embodiment. Whereas the formerly described embodiment includes a puncturer assembly, shown as puncturer assembly  3  in  FIG. 1 , which grasps the tissue to be sutured, punctures the tissue and passes the suture through the tissue all in one movement, with a crochet head thereafter simply engaging the suture, suturing head  70  of the present embodiment has a tissue grasping mechanism  51  which is designed and configured for grasping a tissue and for positioning a suture on a first side of the tissue grasped thereby. Suturing head  70  further includes a separate crochet head  61  which is designed and configured for piercing through the tissue from a second side thereof and engaging the suture following piercing, thereafter enabling drawing the suture through the tissue.  
         [0060]     Thus, in contrast to the formerly described embodiment, suturing instrument  45  includes separate piercing and grasping elements, which enable piercing the tissue and carrying the suture through the tissue following piercing thereof.  
         [0061]     Such a suturing head  70  configuration provides a significant advantage in that it is capable of suturing tissues with a wide range of thicknesses, as there is no puncturer of a specific length to limit the thickness of the tissue capable of being sutured.  
         [0062]      FIGS. 4 and 5  illustrate a detailed view of one preferred configuration of suturing head  70 , illustrating in detail the construction of tissue grasping mechanism  51 , hereinafter referred to as mechanism  51 , and crochet head  61 .  
         [0063]     Mechanism  51  includes a static grasping member, hereinafter referred to as static member  52 , and a movable grasping member, hereinafter referred to as movable member  55 , both positioned at the distal end of suturing instrument  45 .  
         [0064]     Static member  52  is disposed rigidly on an elongated shank which is similar to shank  21  illustrated in  FIG. 1 . Movable member  55  is pivotally mounted to static member  52  by a pin, hereinafter referred to as pivot pin  56 , passing through holes formed in both static member  52  and movable member  55  aligned coaxially. The holes in static member  52  and movable member  55  are sized such that pivot pin  56  is affixed by friction within the hole through static member  52  but is movable relative to the hole through movable member  55 , allowing movable member  55  to rotate thereupon. Accordingly, movable member  55  is pivotally movable relative to static member  52 .  
         [0065]     As described above, mechanism  51  is designed and configured for grasping and holding a tissue to be sutured. Accordingly, static member  52  and movable member  55  each have a face disposed substantially opposite one another. The face of static member  52  which faces movable member  55  is formed with a series of parallel grooves therein and is hereinafter referred to as ribbed surface  53 . Each groove of ribbed surface  53  is shaped and angled such that any tissue in contact therewith will be limited, preferably prevented, from moving with respect to static member  52 .  
         [0066]     The pivotal movement of movable member  55  serves to move the face of movable member  55  both closer to, and farther from, ribbed surface  53 . The movement of movable member  55  is controlled by the movement of the second handle and a coupling rod, which are similar in function to handle  30  and coupling rod  35  described hereinabove with respect to  FIG. 1 . Accordingly, the pivotal motion of handle ( 30 ), transmitted by coupling rod ( 35 ), will cause movable member  55  to pivot with respect to static member  52  in a jawlike manner, the closing motion being for grasping the tissue to be sutured, the opening motion being for releasing the tissue.  FIG. 4  depicts grasping mechanism  51  in a closed position.  FIG. 5  depicts grasping mechanism  51  in an open position.  
         [0067]     Mechanism  51  is also designed and configured for positioning a suture on a first side of a tissue to be sutured. Reference is now made to  FIG. 6  which shows a detailed view of the distal end of movable member  55 . According to the alternative embodiment, movable member  55  has a distal end positioned substantially perpendicular to the face opposite static member  52  in the direction of static member  52 . This angular end of movable member  55  is hereinafter referred to as suture end  57 . Suture end  57  is preferably square or rectangular in shape, although it is appreciated that suture end  57  may be of any shape appropriate for the relevant tissue to be sutured.  
         [0068]     Suture end  57  is formed with a groove along its circumference, or a portion of its circumference, hereinafter referred to as suture groove  58 . Suture groove  58  is sized so as to accept an appropriate suturing material. Accordingly, the previously described closing motion of movable member  55  serves to position a suture disposed within suture groove  58  on a (first) side of a tissue grasped by mechanism  51 .  
         [0069]     Suture end  57  is also formed with an opening therein, hereinafter opening  59 , that is sized to allow crochet head  61  to pass therethrough. Opening  59  is shaped and positioned within suture end  57  such that one of its sides extends toward the circumference of suture end  57  beyond the depth of suture groove  58 . Accordingly, at the location that opening  59  approaches the circumference of suture end  57 , suture groove  58  is exposed to the inside of opening  59  such that a suture disposed therein is accessible from within opening  59 .  
         [0070]     Suturing head  70  further includes crochet head  61 , designed and configured for piercing through a tissue grasped by mechanism  51 , engaging the suture and drawing the suture through the tissue. Crochet head  61  is part of a crochet head assembly  60  which also includes a third handle and coupling slide (similar to coupling slide  43  shown in  FIG. 1 ), The movement of coupling slide  43  and crochet head  61  is controlled by the movement of the third handle, which is similar in function to handle  40  described hereinabove with respect to  FIG. 1 .  
         [0071]     Crochet head  61  is formed with a sharp point for piercing a tissue to be sutured, hereinafter referred to as point  62 , and a hooklike formation, hereinafter referred to as hook  63 , designed to deflect a suture as crochet head  61  first passes the suture when moving in the direction of its extended position and to engage the suture as it subsequently passes the suture moving in a reverse direction toward its retracted position.  
         [0072]     Crochet head  61  is carried at the distal end of coupling slide  43 . Coupling slide  43 , which includes an element slidable with respect to elongated shank  21 , is coupled to the upper end of handle ( 40 ). Handle ( 40 ) is pivotally mounted to the first handle, which is similar in function to handle  20  described hereinabove with respect to  FIG. 1 . Handle ( 20 ) is preferably spring biased (spring not shown) to return handle ( 40 ) to the position whereby crochet head  61  is in its retracted position. The movement of crochet head  61  is controlled by the movement of handle ( 40 ) and coupling slide  43  in substantially the same manner as previously described with reference to  FIG. 1 .  
         [0073]     Accordingly, the pivotal motion of handle ( 40 ) with respect to handle ( 20 ) will cause crochet head  61  to move through forward and return strokes substantially parallel to the longitudinal axis of elongated shank ( 21 ). Crochet head  61  is slidably mounted in proximity to mechanism  51  and is movable through a forward stroke from a retracted position at the proximal end of mechanism  51  to an extended position beyond suture end  57 , and through a return stroke back to the retracted position. The forward stroke of crochet head  61  is for piercing the tissue held by mechanism  51  and the return stroke of crochet head  61  is for engaging the suture and drawing it through the tissue.  
         [0074]     The forward and return movements of crochet head  61  are guided by an inverted U-shaped guide member (similar to member  24  of  FIG. 1 ) which is formed as part of static member  52 . Guide member  24  guides point  62  to pass within opening  59  at a point where opening  59  approaches the circumference of suture end  57  beyond the depth of suture groove  58  such that crochet head  61  passes between the circumference of opening  59  and a suture disposed within suture groove  58 . As described above, the deployment of handles ( 20 ,  30  and  40 ) proximal to one another allows suturing instrument  45  to be easily employed by a user. Once the suture is disposed on suture head  70 , a user may preferably operate each of the handles in proper sequence by the fingers of one hand, as follows.  
         [0075]     First, a suture is disposed within suture groove  58 . Thereafter, suturing instrument  45  is preferably held with the middle finger in the loop of handle ( 20 ), the index finger in the loop of handle ( 40 ) and the thumb in the loop of handle ( 30 ). The distal end of suturing instrument  45  is passed through a cannula and is placed at the surgical site. Handle ( 30 ) is pivoted away from handle ( 20 ) by the thumb so as to pivot movable member  55  such that grasping mechanism  51  is in its open position, as shown in  FIG. 5 , to enable grasping mechanism  51  to grasp a tissue to be sutured. With grasping mechanism  51  in the open orientation, the instrument is positioned such that a tissue to be sutured is placed within the gap between static member  52  and movable member  55 .  
         [0076]     Handle ( 30 ) is then pivoted towards handle ( 20 ) to pivot movable member  55  toward ribbed surface  53  causing mechanism  51  to move to its closed position (as shown in  FIG. 4 ) in order to both grasp the tissue and position the suture on the side of the tissue. Closing mechanism  51  causes opening  59  to align with guide member ( 24 ). Handle ( 40 ) is then pivoted toward handle ( 20 ) with the index finger to move crochet head  61  through a forward stroke from its retracted position at the proximal end of mechanism  51  to beyond suture end  57 . Handle ( 40 ) is then released to permit its spring bias to return crochet head  61  through a return stroke back to its retracted position at the proximal end of mechanism  51 . If necessary, the index finger in the loop of handle ( 40 ) could forcibly pivot handle ( 40 ) away from handle ( 20 ) causing crochet head  61  to return to its retracted position.  
         [0077]     During the movement of crochet head  61  in the forward stroke, point  62  pierces and penetrates through the tissue grasped and thereafter passes between the suture within suture groove  58  and the circumference of opening  59 . Crochet head  61  is thus moved sufficiently past the suture such that hook  63  engages the suture on the return stroke and draws it through the hole pierced through the tissue. Handle ( 30 ) is then pivoted away from handle ( 20 ) by the thumb to move mechanism  51  to its open position, and thereby to release the tissue. Thereafter, suturing instrument  45  may then be withdrawn from the cannula, drawing the suture with it.  
         [0078]     The suturing instruments of the present invention offer a number of substantial advantages over previously described suturing devices. The first advantage is simplicity of construction. Both embodiments of the suturing instrument are of simple mechanical design and are fabricated from a relatively small number of moving parts. In addition, the suturing instruments of the present invention do not depend upon excessively close tolerances to function effectively.  
         [0079]     Furthermore, the suturing instruments of the present invention may be employed with one hand; once the suture is deployed on the device, the tissue may be grasped and the suture completed solely by the movement of the fingers of one hand, leaving the other hand free.  
         [0080]     Finally, the suturing instruments of the present invention provide a positive and reliable method of effecting a suture from a remote location, thus avoiding missed stitches, a limitation which plagues devices employing separate piercing and retracting elements.  
         [0081]     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.  
         [0082]     Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually, indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.