Abstract:
A surgical instrument that automatically ties simple interrupted sutures is described. The user adjusts the tension in the suture loop. The instrument can use any of the currently used suture materials. In one form, sutures, a needle and two small blades come in a modular unit that is attached to a main piece. The advantages of conventional suturing are combined with the practicality of a surgical stapler.

Description:
BACKGROUND 
   This invention pertains to an instrument and method for automating the conventional suturing process routinely performed during open and endoscopic surgeries. 
   Conventional suturing, where a practitioner manually sutures tissues with a needle and suture material, is still the preferred method and has not been replaced by any other technique. However, it is a time consuming process and this inconvenience becomes even more pronounced during endoscopic surgeries. 
   Most of the time a simple interrupted suture is what is needed, and a surgeon&#39;s knot is the type of knot used. In order to tie a simple interrupted suture, a needle, a suture material attached to the needle and three additional instruments are generally used: a needle holder, a forceps and a pair of scissors. 
   To suture during an open surgical operation, first an assistant takes a needle out of a needle dispenser with a needle holder and then hands the needle holder to the practitioner with the tip of the needle pointing left or right depending on whether the practitioner is right- or left-handed. The practitioner manipulates and positions the tissues or the structures to be sutured with a forceps in his/her other hand and passes the needle and the attached suture material through them. To form a surgeon&#39;s knot, first a double-wrap throw is made, followed by a single-wrap throw in the reverse direction. To make a double-wrap throw, the needle-attached end of the suture material is wrapped around the distal body of the needle holder twice in the same direction. The other end of the suture material is grasped with the needle holder to pull through the wrappings made around the needle holder while the needle-attached end of the suture material is pulled in the opposite direction. After desired tension on the tissues or structures within this first loop is attained, the ends of the suture material are released. To make a single-wrap throw, the same process is repeated wrapping around the needle holder only once and in the reverse direction. This creates a second loop, and its size is reduced to a minimum by pulling on the ends of the suture material to secure the knot. Following final tightening the excess lengths of the suture material on both ends are cut, usually by the assisting person. 
   Endoscopic surgeries, on the other hand, are surgeries performed with the aid of an endoscope, which is basically a video camera. The surgical site is reached through one or more small ports. Special elongated instruments including an endoscope are introduced through these ports. Direct view of the surgical site is not available, but a limited indirect view is provided by the endoscope. Therefore, simple but time-consuming maneuvers described above for an open surgery (such as wrapping a suture material around an instrument, passing the needle from one instrument to another) become more tedious and more time consuming. Incidents such as dropping the needle may become a real issue. Therefore, most of the efforts to advance the state of the art of suturing have been intended to facilitate endoscopic suturing. 
   Among all the steps of suturing, tying a knot is the lengthiest and the one that involves the most manipulation, and several patents address this step. For example, U.S. Pat. Nos. 5,002,563 (Pyka, et al), 5,259,846 (Granger, et al), 5,368,599 (Hirsh, et al.), 5,403,346 (Loeser), 5,520,702 (Sauer, et al.), 4,592,355 (Antebi), 5,123,913 (Wilk, et al.), 5,330,503 (Yoon), 5,643,295 (Yoon), 4,981,149 (Yoon, et al.), 5,683,417 (Cooper), 5,931,855 (Buncke), 5,984,933 (Yoon), 5,919,208 (Valenti), 6,010,525 (Bonutti, et al.), 6,066,160 (Colvin, et al.), and 6,099,553 (Hart, et al.), are representative of suture devices, or suture materials of special structures designed to avoid forming knots. U.S. Pat. Nos. 5,725,522 (Sinofsky), 5,565,122 (Zinnbauer, et al.), 6,077,277 (Mollenauer, et al.), 5,417,700 (Egan), and 6,106,545 (Egan) suggest using laser radiation or radiant heat to effect fusion instead of tying knots. These patents are mostly for techniques to avoid tying a knot altogether. The ones on facilitating tying knots, on the other hand, are almost exclusively for endoscopic surgeries. 
   There are at least three ways of tying sutures during an endoscopic surgery. One way is taking both ends of the suture material out after passing it through the tissue and forming the knot extracorporeally and pushing it back inside the surgical field. U.S. Pat. Nos. 5,084,058 (Li), 5,087,263 (Li), 5,257,637 (El Gazayerli), 5,403,330 (Tuason), 5,769,863 (Garrison), 5,234,444 (Christondias), 5,217,471 (Burkhart), and U.S. Pat. No. 5,752,964 (Mericle) are examples of knot pushers. A second way of tying sutures during endoscopic procedures is of course forming and tying knots intracorporeally, which is extremely tedious. However, there are some instruments designed to help tying knots intracorporeally especially for forming loops. U.S. Pat. Nos. 5,192,287 (Fournier, et al.), 5,201,744 (Jones), 5,716,368 (de la Torre, et al.), 5,810,852 (Greenberg, et al.), 5,383,877 (Clarke), 6,045,561 (Marshall, et al.), 6,086,601 (Yoon), 5,234,443 (Phan, et al.), 4,641,652 (Hatterer, et al.), and 5,480,406 (Nolan, et al.) are examples of this class. 
   Use of preformed knotted loops is the third way of tying sutures during endoscopic surgeries. U.S. Pat. Nos. 5,405,352 (Weston), 5,330,491 (Walker, et al.), 5,449,367 (Kadry), 5,643,293 (Kogasaka, et al.), 5,846,254 (Schulze, et al.), 5,211,650 (Noda), 5,320,629 (Noda, et al.), and 5,144,961 (Chen, et al.) disclose devices using preformed knotted loops or partially tied knots within which the needle is passed and the suture is tied. 
   There are also patents addressing the steps of suturing other than tying knots, such as manipulation of the needle and suture threading. Some of these inventions also assist forming knots during endoscopic procedures. Others disclose a specific needle or a needle holder design. Some examples of this class of patents are U.S. Pat. Nos. 4,373,530 (Kilejian), 4,164,225 (Johnson, et al.), 4,345,601 (Fukuda), 4,557,265 (Andersson), 4,596,249 (Freda, et al.), 5,318,577 (Li), 5,474,565 (Trott), 5,569,270 (Weng), 5,540,705 (Meade, et al.), 5,520,703 (Essig, et al.), 5,772,672 (Toy, et al.), 5,746,754 (Chan), 5,741,279 (Gordon, et al.), 5,665,096 (Yoon), 4,957,498 (Caspari, et al.), 5,776,150 (Nolan, et al.), 5,766,186 (Faraz, et al.), 5,951,587 (Qureshi, et al.), 5,954,733 (Yoon), 5,152,769 (Baber), 6,074,404 (Stalker, et al.), 6,071,289 (Stefanchik, et al.), 5,814,054 (Kortenbach, et al.), 5,895,395 (Yeung), and 5,364,409 (Kuwabara, et al.) 
   A particularly successful invention in this field has been the surgical stapler. In some limited set of applications, the surgical stapler has been able to replace conventional suturing for many practitioners. There are quite a number of patents disclosing surgical staplers designed to be used during open surgeries (e.g., U.S. Pat. Nos. 4,470,532 (Froehlich), 5,893,855 (Jacobs), 4,664,305 (Blake, III, et al.), 4,583,670 (Alvarado), RE28,932 (Noiles, et al.), 4,592,498 (Braun, et al.), 3,949,924 (Green), 5,697,543 (Burdorff) or endoscopic surgeries (e.g., U.S. Pat. Nos. 5,392,978 (Velez, et al.), 5,470,010 (Rothfuss, et al.), 5,553,765 (Knodel, et al.), 5,554,169 (Green, et al.), 5,810,855 (Rayburn, et al.), 5,829,662 (Allen, et al.). 
   Surgical staplers are actually very similar to their office counterparts. They dispatch staples to clip and hold tissue together. The surgical staples, however, can be made of metal or absorbable materials. They are designed to combine the functions of a needle and a suture material in one body. They need to penetrate the tissue like a needle and hold the grasped tissue like a tied suture material. Metal staples may be thought of needles bent and left in tissue. Even though the ends of staples are left free, since they are able to preserve their new shape they fix the tissue edges. Metal staples are not absorbable. Absorbable staples, on the other hand, require an extremely large amount of material to be introduced into the body to provide a secure fastening (see U.S. Pat. No. 5,507,776 (Hempel)). 
   The reason that staplers have found applications in today&#39;s field of surgery is often not because they are superior to conventional suturing in terms of the results they provide, but because it is faster to staple with a simple maneuver. One of the disadvantages of staplers is that the tension applied on the grasped tissue by staples cannot be adjusted. It is sometimes too loose, sometimes too tight. Also scars caused by stapling are usually worse than scars with conventional suturing. This is why staplers are usually used where esthetical results are not sought. In addition many surgeons prefer the security of sutures to staples. 
   A suturing apparatus described by Klundt, et al. (U.S. Pat. No. 5,496,334) automatically sutures by performing a single-thread overcast stitching operation, like a sewing machine; however this apparatus cannot tie single interrupted sutures. 
   Therefore, there is a need for an instrument that automates what a practitioner does during a conventional suturing process, which in spite of many recent inventions is often still the preferred method of closing wounds. Such an instrument would preferably combine the practicality of a stapler with the advantages of conventional suturing. 
   SUMMARY 
   The preferred embodiment described below is an instrument for suturing tissue in open and endoscopic surgeries, and it ties simple interrupted sutures with non-slip knots in an automatic manner. This embodiment can use all available suture materials used in conventional suturing today, as well as new suture materials developed in the future. 
   The illustrated embodiment automatically passes suture material through tissue, and then automatically ties a desired type of non-slip knot after passing the suture material through the tissue. This embodiment leaves the adjustment of the tension within the suture loop to the practitioner, and it automatically cuts the extra lengths from the ends of the suture material on both sides of a knot. 
   This embodiment allows multiple interrupted sutures to be placed without reloading. It executes the above steps sequentially and can repeat them without creating a need for the practitioner to change hands or take the instrument out of the surgical site in endoscopic surgeries. 
   The foregoing paragraphs have been provided by way of general introduction, and they should not be used to narrow the scope of the following claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1   a  is a perspective view of a suturing device that incorporates a preferred embodiment of this invention, with the suture delivery module removed. 
       FIG. 1   b  is a fragmentary perspective view of the suturing device of  FIG. 1   a , with the suture delivery module installed. 
       FIG. 2   a  is a schematic diagram of a suture carrier included in the embodiment of  FIG. 1   b.    
       FIG. 2   b  is a perspective view of a needle guide and a needle included in the embodiment of  FIG. 1   b.    
       FIGS. 2   c ,  2   d  and  2   e  are perspective views of three alternative arrangements for coupling a suture to the pointed end of the needle of  FIG. 2   b.    
       FIG. 2   f  is a perspective view of a plurality of sutures and associated structures included in the suture delivery system of  FIG. 1   b.    
       FIG. 2   g  is a perspective view of selected components of the embodiment of  FIGS. 1   a  and  1   b.    
       FIG. 2   h  is an enlarged perspective view showing the relationship between the suture delivery system of  FIG. 2   f  and the needle guide of  FIG. 2   b.    
       FIGS. 3   a  through  3   f  are sequential views illustrating a method for tying a surgeon&#39;s knot in a suture. The illustrated method can be implemented with the embodiment of  FIGS. 1   a  and  1   b.    
       FIG. 4  is a perspective view of components of the embodiment of  FIG. 1   a  that operate to tighten knots in the sutures. 
       FIGS. 5   a  and  5   b  are perspective views illustrating components coupled to the actuators of the embodiment of  FIG. 1   a.    
       FIGS. 6   a ,  6   b  and  6   c  illustrate components of the embodiment of  FIG. 1   a  that couple the actuators to the suture delivery system. 
       FIG. 7  is a schematic representation of an example of a partially tied knot suitable for use with this invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Overview 
   Turning now to the drawings, the operation of the suturing device  100  of  FIGS. 1   a  and  1   b  will first be described generally using the schematic diagrams of  FIGS. 3   a  through  3   f.  The discussion will then turn to a detailed description of the structure and operation of the suturing device  100  in its presently preferred form. 
   As shown in  FIGS. 1   a  and  1   b , the suturing device  100  includes a frame  101  that supports an operating portion  110  and a handle portion  120 . The handle portion  120  is intended to be held in the hand of a surgeon, and it includes first and second actuators  121 ,  122 . In this embodiment the actuators  121 ,  122  pivot in the manner of triggers with respect to the handle portion  120 , though other sliding or pivoting motions can also be used. 
   The operating portion  110  supports at its distal end a removable suture delivery system  300 . The suture delivery system  300  includes a modular housing  301  intended to fit over and then to be removed from the operating portion  110 . The suture delivery system  300  includes many suture assemblies  303 , each mounted on a carrier support  330  ( FIG. 2   f ). The suture delivery system  300  also includes a needle guide  315  that is arcuate in shape and that supports an arcuate needle  310  for sliding movement in the guide  315  ( FIG. 2   b ). The spatial relationship between the needle  310  and the suture assemblies is shown generally in  FIG. 2   h.    
   The operation of the suturing device  100  can best be understood in general terms with reference to  FIGS. 3   a-   3   f.    FIG. 3   a  shows a schematic view of one of the suture assemblies  303  in an initial condition. The suture assembly  303  includes a suture  340  having a first end  341  connected to a spool  395  and a second end  342  connected to an enlarged element  343 . The suture  340  is wrapped in a plurality of coils  344  around a tube  360 . For example, the tube  360  may have grooves in the walls of the tube to receive the suture  340 , and these grooves may be closed at their inner surface by a frangible material. 
   The tube  360  in this embodiment is U-shaped, and the tube  360  includes a first leg  360   a  and a second leg  360   b  interconnected by a bight section  360   c.    
   The suture assembly  303  also includes a suture carrier that includes a line  373  and a gripping element  370 . The line  373  has a first end  373   a  that is connected to a spool  394  and a second end  373   b  that is connected to the gripping element  370 . The gripping element  370  is adapted to grip and hold the enlarged element  343  that is secured to the second end  342  of the suture  340 . 
   The spools  394 ,  395  are rotatable by respective spool drivers  390 ,  391 , and a spacer  380  is positioned between the two legs  360   a ,  360   b  of the tube  360 . 
   In order to initiate the process of tying a suture knot with the suturing device  100 , the surgeon positions the suture delivery system  300  appropriately and then squeezes the first actuator  121  to move the needle  310  from its original, retracted position ( FIG. 2   h ) to an extended position, which causes the needle to engage the enlarged element  343  and the associated suture and then to pierce the two tissues to be joined by the suture. When the needle  310  is fully extended in the guide  315 , the needle  310  inserts the enlarged element  343  into the gripping element  370  (as shown in  FIG. 3   b ), thereby forming the first loop  345  in the suture. 
   As the surgeon continues depressing the first actuator  121 , the suturing device  100  rotates the spool driver  390  and the spool  394 , thereby winding the line  373  on the spool  394  and pulling the gripping element  370  and the attached enlarged element  343  through the tube  360 , as shown in  FIG. 3   c . Note that this action causes the second end  342  of the suture  340  to pass through the preformed coils  344  and forms the second loop  346  in the suture. In this text, the term “second loop” also indicates the pre made loop  346 ′ of a partially tied knot ( FIG. 7 ) when a partially tied knot is used, although it is not exactly the same second loop that is obtained with the use of a coiled suture. In both cases the first loop indicates the one that encircles the tissue. 
   Continued motion of the first actuator  121  causes the suturing device  100  to rotate the spool driver  391  and the spool  395 , thereby winding the first end  341  of the suture  340  around the spool  395 . This increases the tension second loop  346  of the suture  340 , thereby causing the suture  340  to break through the breakable material that makes up the walls of the tube  360 . This first brings the preformed coils of the suture  340  into intimate contact with the second end  342  of suture  340 , as shown in  FIG. 3   d  and then positions the second loop  346  closely around a spacer  380 , as shown in  FIG. 3   e.    
   The spacer  380  prevents the loop  346  from tightening on the loop  345  as the loop  345  is itself being tightened and it allows the loops  345 ,  346  to be tightened independently of one another. When the operation shown in  FIG. 3   e  has continued to the point where an adequate tension is developed in the loop  345  of the suture  340  that passes through the tissue, the surgeon then releases the first actuator  121  and begins to depress the second actuator  122 . As a consequence of this actuation, the spacer  380  is removed, and the knot is fully tensioned, as shown in  FIG. 3   f.  As the spacer  380  is pulled out of the loop  346 , both ends of the suture are pulled simultaneously applying equal forces in order to tighten the loop  346  and form a non-slip knot. When the spacer  380  is totally removed from the loop  346 , the knot becomes secured and the shafts driving the spools  394 ,  395  are automatically stopped. 
   Release of the second actuator  122  causes the used suture assembly  303  to be moved out of alignment with the needle guide  315 . This motion causes the fully tied knot to move past two trimmer blades  320  that trim the excess suture on both sides of the knot. Release of the second actuator  122  also indexes a next suture assembly into alignment with the needle guide, thereby preparing the suturing device  100  to tie a next suture. 
   The example of  FIGS. 3   a-   3   f  illustrates a method for tying a surgeon&#39;s knot. This method can readily be adapted to other knots. It is possible to obtain different types of knots by changing the number of coils around the first leg  360   a  and the second leg  360   b  of the tube, or by arranging the coils of the sutures around a one-legged tube instead of a two-legged U-shaped tube, or by placing the loop  346 ′ of a partially tied knot around a tube  360 ′ ( FIG. 7 ) instead of wrapping a suture in coils. 
   Of course, many other variations are possible. For example, in one alternative the end of the suture that is gripped by the gripping element can be wrapped around the other end of the suture by pulling it through a tube that is itself wrapped around the other end of the suture. In this case, the suture carrier is placed in the coiled tube around the suture. As before, the suture end is pulled by the suture carrier to make the desired wraps and create the desired knot. With above examples, it should be apparent that the tube illustrated and discussed above can be straight, curved, U-shaped or coiled. It may or may not be cylindrical in cross-section, and it should be understood that the term “tube” is intended broadly to encompass a wide variety of structures that create the desired canal or passage and support coils or loops of a suture. 
   The gripping element of the suture carrier may be placed behind or at the same level as the coils of the suture or the loop of the partially tied knot when they are wrapped around a one-legged tube in the direction of movement of the needle tip as it approaches the tube. Where the gripping element is placed behind the coils or the loop, the second end  342  of the suture and the enlarged element  343  are passed through the tube by the needle. In this variation the suture carrier may consist of only a gripping element, which may also work as a spool. 
   The term “wrapped around ” is intended broadly to encompass a wide variety of wrapping arrangements that accomplish the purposes set out above. For example, a suture or a suture carrier may be placed on the outer circumference of the tube, may be placed in inwardly-opening or outwardly-opening grooves in the walls of the tube, or may be placed in suitable slots in the walls of the tube. 
     FIG. 7  shows an example of a partially tied knot that can be used with the method of this invention. The loop  346 ′ of this partially tied knot is wrapped around a tube  360 ′, which is represented by the double solid horizontal lines. One end of the suture (shown by an arrow) is passed through this loop  346 ′ after it has passed through tissue and before or after it has been gripped by a suture carrier (not shown). The other end of this partially tied suture will be directly connected to a spool or other device for shortening the effective length of the suture. In this example, the tube  360 ′ may have a length substantially less than its circumference. 
   Presently Preferred Implementation 
   Many alternative structures can be used to implement the suture tying method described above, including manually-powered, electrically-powered, and hydraulically or pneumatically-powered devices. The following discussion presents one such structure by way of example, and not by way of limitation. 
   The term “distal” in this text is used to indicate far from the user and “proximal” close to the user. 
   The preferred embodiment of the instrument includes two parts: a main piece  100 , and a modular piece  300  ( FIGS. 1   a ,  1   b ). 
   The modular piece  300  carries a curved needle  310 , two small blades  320 , and suture assemblies that are mounted on a movable flexible support element  330  ( FIGS. 2   a-   2   h ). The support element surrounds the needle on three sides (the concave side, the distal lateral side, and the convex side) and moves around the needle ( FIG. 2   h ). 
   The two small blades are positioned at the tip of the modular unit ( FIG. 2   g ). They stay parallel to the longitudinal axis of the support element. The needle is a semicircle ( FIG. 2   b ). One end of the needle has a handle  311 , which has a hole  312  to accept the tip of a crank  147  ( FIG. 1   a ). It steps back to a larger diameter than the needle. A gripping element  370  is positioned in front of the handle of the needle in its primary position. The needle is in a wide enough canal  315  to also accommodate the handle of the needle so that both the needle and the handle can move along it. The canal has an open end  316 , where the tip  314  of the needle rests, and a slot  317  along the side facing the crank  147 . The end of the suture  342  coming overhead the needle tip has an enlarged element  343  configured to be caught by the tip of the needle and to facilitate gripping by the gripping element described below. When the needle is driven all the way along the canal, the tip  314  together with the caught end of the suture enters into the gripping element  370 . 
   The enlarged element  343  of the suture and the tip  314  of the needle can take many forms. In the example of  FIG. 2   c , the enlarged element  343  fits within a slot  313  in the needle tip  314 . In the example of  FIG. 2   d , the enlarged element  343 ′ fits on a post that forms the needle tip  314 ′, and it is the enlarged element  343 ′ that forms the piercing edge of the needle. In the example of  FIG. 2   e , the enlarged element  343 ″ is pierced by the sharpened needle tip  314 ″, and the tip  314 ″ forms the piercing edge of the needle. 
   Sutures are each placed on the support element  330  in relation to a respective U-shaped tube or canal  360 , a gripping element  370  and two spools  394 ,  395 , all of which will be referred to as a suture assembly ( FIG. 2   f ). In other embodiments, the suture assembly may not include spools and it may include other types of canals and gripping elements. 
   The U-shaped canals  360  are positioned on the support element so that their legs point in the opposite direction to the needle tip ( FIG. 2   h ). The tip  361  of the canal&#39;s distal leg has a larger diameter then the rest of the canal and accommodates the gripping element. This part of the U-shaped canal is situated at the recess created by the handle of the needle stepping back to a larger diameter than the needle. The U-shaped canal has a slot  363  along its shorter curve and an open roof  364  for a certain distance from the tip of its distal leg ( FIG. 2   f ). The widths of these openings  363 ,  364  are smaller than the shorter diameter of the U-shaped canal  360 . Transverse slits  365  on the legs of the U-shaped canals allow the blades  320  to pass through. 
   At its primary position, the gripping element  370  rests at the tip of the distal leg  361  of the U-shaped canal ( FIG. 2   g ). It is cylindrically shaped and made of a compressible material, which is supported with an embedded spiral wire  371  ( FIG. 2   a ). It has also a slit  372  where the tip of the needle together with the enlarged element  343  and the associated end  342  of the suture enters. The spiral wire goes to the top of the gripping element  370 , and the other end comes out as a line  373  from the other end. This line  373  follows the U-shaped canal  360  and is attached to a spool  394  at the other end of the U-shaped canal  360 . When it is wound up, the line  373  pulls the gripping element  370  through the smaller diameter part of the U-shaped canal  360  to increase its gripping capability. 
   There are grooves  366  carved on the walls of the U-shaped canal ( FIG. 2   f ). These grooves make spirals on the inside walls of the legs of the U-shaped canal  360 . The spiral grooves have a selected number of turns on each leg depending on the knot type, e.g., one turn in each leg for a square knot and two turns in the distal leg and one in the proximal leg for a surgeon&#39;s knot. The sutures  340  are laid in these grooves  366  (one suture for each U-shaped canal  360 ). The grooves are covered with a thin layer of a frangible material. This thin layer of material (that is easily tom when the suture is pulled) contains the sutures within the grooves and lets the gripping element glide through the tube without tangling. In its primary position, a suture is disposed in a “U” shape reverse to and partially overlapping with the U-shaped canal ( FIG. 3   a ). One end  342  of the suture is aligned with the needle tip and the other end  341  is attached to a second spool  395  which is level with the first spool  394  in the proximal-to-distal direction and is on the other side of the U-shaped canal. 
   The support element  330  is flexible and can be moved around the needle  310  ( FIG. 2   h ). It carries multiple suture assemblies. The modular piece  300  has two openings  302 ,  303  in addition to the one  301  that accepts the nozzle  110  ( FIG. 2   g ). One of the openings  302  is aligned with the open roofed part of the U-shaped canal  364 , and the other  303  is aligned with the needle tip. A slot connects these two openings. 
   Also, there are several openings on the floor of the support element for different purposes ( FIG. 2   f ). There is an opening  331  in between the U-shaped canal legs to accept a spacer  380  when the spacer is raised with its platform  383  from within the nozzle of the main piece. The spacer is a dome shaped bar that stands perpendicular to its platform. There are two holes  332  underneath the spools to accept two corresponding spool drivers  390 ,  391  when they are raised with their platform  392  from within the nozzle of the main piece. The openings  334  that allow the needle to pass are also where the enlarged ends  343  of the sutures are releasably held. Finally there are openings  333  to accept the cogs of the cogwheels  410 , which advance the support element. Each time the support element is advanced it brings a new suture assembly in front of the needle on the concave side and takes away the used assembly. The used assemblies are stored in the storage space  350  of the modular piece, which is the space turning around the needle and continuing at the convex side of the needle and the nozzle ( FIG. 2   g ). 
   The overall shape of the modular piece  300  resembles a glove finger and is worn on the nozzle of the main piece  110  from distal to proximal direction and snugly fits on it ( FIGS. 1 ,  2   g ). A clip mechanism  304  holds the modular piece attached to the main piece ( FIG. 2   g ). 
   The main piece  100  includes a handle  120 , a body  130  and a nozzle  110 , and it carries the operating elements and their related pieces. Some pieces are common for some operating elements. 
   The nozzle is elongated in the preferred embodiment for endoscopic use. The cross-section of the nozzle perpendicular to its long axis is curved conforming to the shape of the needle. A separator extending along the nozzle divides it into inner  111  and outer  112  spaces ( FIG. 2   g ). 
   The outer space  112  is an empty space allowing a crank  147  to sweep from one end to the other and back to its primary position. 
   The crank  147  protrudes from the nozzle to enter in the hole  312  at the needle&#39;s handle when modular piece is connected ( FIG. 2   g ). It has also four processes  146  protruding into the inner space of the nozzle. The inner space contains two spool drivers  390 ,  391  and a spacer on two separate platforms  392 ,  383  (FIG.  4 ). The spacer platform  383  is distal to the spool driver platform  392 . Two rotors  174 ,  175 , which rotate the spool drivers, also extend along the nozzle in the inner space. While pushing the needle, the rotation of the crank  147  also raises the platforms of the spool drivers and the spacer by elevating and pushing the supporting blocks  384 ,  393  under them through its processes  146  extending into the inner nozzle space  111 . These platforms  383 ,  392  are biased separately by springs  385 ,  396  when the blocks are pushed back to their first position. 
   Advancing means including cogwheels  410  placed in the nozzle propel the support element for a certain distance each time the primary actuator  121  is released ( FIG. 2   g ). An arm  200  that can rotate the cogwheels in only one direction after pushing the supporting blocks of the spool driver platform accomplishes this. These cogwheels are oval so that they only temporarily protrude out of the nozzle when rotated. 
   The handle  120  has two actuators: primary  121  and secondary  122  ( FIG. 5   a ). They work against springs  123 ,  124 . When flexed, the. primary actuator  121  pushes a multiple piece shaft, which in turn moves the crank  147  and rotates the rotors of the first and the second spools. Due to a serrated ratchet track  190 , the actuator  121  holds its flexed or depressed position when it is released. During its flexion, the actuator  121  also flexes the secondary actuator  122  passively. This makes the secondary actuator able to take over the pushing of the shaft further from where the primary actuator leaves off. Activation of the secondary actuator locks the primary actuator and pushes the shaft for a certain distance. Upon its release, after having been flexed, the secondary actuator  122  releases the primary actuator  121 , which then returns to its original position. As it returns, the primary actuator lowers the spool driver platform to its primary level and propels the support element, thereby indexing a next suture assembly into position in alignment with the needle. 
   The shaft includes five cylindrically shaped structures  140 ,  141 ,  142 ,  143 ,  144  longitudinally placed in a single line in the body ( FIGS. 6   a ,  6   b ). The distal three  142 ,  143 ,  144  and the proximal one  140  are hollow. When they are numbered from proximal to distal, number one  140 , two  141  and four  143  can only be advanced, number three  142  can be advanced and rotated, and number five  144  can only be rotated. The crank  147  is an attachment of the fifth cylinder and protrudes in the same direction as the nozzle. 
   When they are at their primary position and the primary actuator begins to flex, number one through four cylinders are pushed forward by way of an extension  125  ( FIG. 5   a ) entering into the first cylinder through a cleft on the wall  157 . By a screw mechanism  148  number five  144  and therefore the crank  147  start to rotate. It can be rotated to make only half a circle, being dependent on the length of the screw thread and the corresponding groove and the limited longitudinal movement of the fourth cylinder. The length of this longitudinal movement equals the length of the restraining columns  149  fitting into the corresponding grooves on the sides of the third cylinder  150  that prevent it from rotating. When the third cylinder is relieved from this restraint, it starts to rotate until its two processes  151 , which originally push the fourth cylinder, enter into grooves  152  at the outer sides of the fourth cylinder. This prevents the fourth and hence the fifth cylinder from being pushed any farther and the fourth cylinder is then moved by a spring  155 . This motion rotates the fifth cylinder in reverse direction because of the unscrewing action. The length of the third cylinder&#39;s processes  151  and the fourth cylinder&#39;s grooves  152  allow further advancement of the first, second and third cylinders without disturbing the fourth and the fifth. This advancement causes two toothed bars  170 ,  171  of unequal length to rotate the horizontal cogwheels  178 ,  179 , which in turn rotate the rotors  174 ,  175  ( FIGS. 4 and 6   b ). The rotors cannot move in the proximal-distal direction. At their distal and proximal ends the rotors have cogwheels  176 ,  177  that stay in the coronal plane. The distal cogwheels  176  of the rotors rotate the spool drivers  390 ,  391 , and the proximal cogwheels  177  are rotated by the two horizontal cogwheels  178 ,  179 . The two-toothed bars  170 ,  171  ( FIG. 6   b ) are two processes of the distal flat surface of the second cylinder. Therefore, pushing the second cylinder causes the spools to rotate ( FIGS. 4 ,  6   b ). The difference in the lengths of the toothed bars determines the starting time of the spools&#39; rotations relative to each other. When the end of the suture  342  is introduced into the gripping element.  370 , the first spool&#39;s rotor  174  (which winds the suture carrier line  373 ) starts rotating, and it stops when the other rotor  175  starts rotating. A process  172  on the side of the longer toothed bar  170  disconnects the corresponding horizontal cogwheel  178  from its rotor  174 . This process  172  of the longer toothed bar  170  is at the same proximal-to-distal level with the tip of the shorter toothed bar  171  ( FIG. 6   b ). 
   When the user assesses the tension within the suture loop that passes through the tissue as appropriate, he stops flexing the primary actuator. This stops the rotation of the second spool  391  and hence the winding process, but the primary actuator  121  is not released due to the serrated ratchet track  190 . 
   Then the user starts flexing the secondary actuator. This action prevents the primary actuator from further flexion by pushing a stopper  180 , which fixes the primary actuator at its current position and also overrides the serrated ratchet track ( FIGS. 5   a ,  5   b ). 
   A part of the second cylinder  156  is inside the first cylinder and it can be moved for a certain distance within the first cylinder. There is a spring  153  inside the first cylinder for pushing this part of the second cylinder and hence the second cylinder along this distance ( FIG. 6   b ). In its primary position, an extension  126  of the secondary actuator blocks this spring by conveying the opposing force of the spring of the secondary actuator  124 . Note that the primary function of this spring of the secondary actuator is to restore the secondary actuator to its starting position when it is released. 
   The first cylinder is advanced by the primary actuator during its flexion together with the other cylinders that can be advanced  141 ,  142 ,  143 , and cannot go backward unless the primary actuator is released. Therefore the secondary actuator cannot move the first cylinder. 
   Flexing the secondary actuator lets the spring in the first cylinder  153  exert its force on the second cylinder and push it for a predetermined distance starting from where the primary actuator left the second cylinder. This distance is a certain distance because after the loop  345  is tightened to the desired degree the length of pulling distance required to tighten the loop  346  is known ( FIG. 3   e ). 
   When activated by flexing the secondary actuator, the system pushes on a mechanism  160  on the wall of the first cylinder before propelling the second cylinder. The mechanism ( FIG. 6   c ) pushes a string  161  perpendicular to the longitudinal axis to shorten the string in the longitudinal direction. This shortening is translated first to reconnection of the disconnected horizontal cogwheel  178  with the corresponding rotor  174  and then to the downward motion of the spacer&#39;s platform. Therefore, with the flexion of the secondary actuator the two rotors simultaneously wind to reduce the size of the loop  346  while keeping the tension in the loop  345  constant. When the secondary actuator is released it is restored to its original position by a spring  124 . When it is restored, it lets the stopper  180  that it has pushed to lock the primary actuator to recover and thus releases the primary actuator. Then the primary actuator is restored to its original position by its spring  123  and this movement pushes the supporting blocks under the spool driver platform to lower the platform and moves the support element forward by sequentially pushing the arm  200 . 
   Release of the primary actuator also allows a spring  154 , which becomes unopposed, to restore the third and hence the second and the first cylinders to their original positions. Meantime, the reducing spring of the secondary actuator loads the spring in the first cylinder. 
   In the illustrated example, the user initiates first and second triggering events by squeezing the first and second actuators, thereby initiating the various operations described above. In this example, the user only squeezes the second actuator once the tension on the suture loop that passes through the tissue is at the desired level. Alternatively, the second triggering event may be initiated automatically when the tension on the suture loop that passes through the tissue reaches a pre-set level. 
   Because the spacer  380  has a tapered top, and the spacer  380  is progressively lowered as the second loop  346  is tightened (after the second triggering event), the spacer maintains tension in the first loop  345  as the second loop  346  is tightened. 
   The main piece can be shaped differently, as appropriate for the application. For example, the operating portion of the main piece can be made to rotate over an arc of e.g. 180° to make use of the main piece more comfortable when the modular piece is inverted or oriented at some other angle in use. 
   As used here, the term “set” means one or more. The term “coupled with” is intended broadly to include direct coupling (when a first element engages a second element directly) and indirect coupling (when a first element is coupled to a second element by one or more unnamed intermediate elements). 
   Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.