Abstract:
A suturing instrument is configured for to apply sutures to approximate, ligate, or fixate tissue in, for example, open, mini-incision, trans-vaginal, or endoscopic surgical procedures. The suturing instrument includes an elongate body member, a needle exit port, a needle receiving port, and a needle deployment mechanism. The suturing instrument eliminates the need for a preassembled needle and suture and reduces or eliminates the possibility of needle loss during suturing.

Description:
CROSS-REFERENCE TO RELATED CASES 
     This application claims priority to and is a continuation of U.S. application Ser. No. 12/879,075, filed on Sep. 10, 2010, which claims priority to and is a continuation of U.S. patent application Ser. No. 11/136,805, now U.S. Pat. No. 7,815,654, filed on May 24, 2005, which in turn claims priority to and is a continuation of U.S. patent application Ser. No. 10/200,271, now U.S. Pat. No. 6,936,054, filed on Jul. 22, 2002. The contents of each of these related cases are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The invention relates to devices and methods for placing sutures. 
     BACKGROUND INFORMATION 
     Suturing of body tissue is a time consuming aspect of many surgical procedures. For many surgical procedures, it is necessary to make a large opening in the human body to expose the area that requires surgical repair. There are instruments available that allow for viewing of certain areas of the human body through a small puncture wound without exposing the entire body cavity. These instruments, called endoscopes, can be used in conjunction with specialized surgical instruments to detect, diagnose, and repair areas of the body that previously required open surgery to access. 
     Some surgical instrument. used in endoscopic procedures are limited by the manner in which they access the areas of the human body in need of repair. In particular, the instruments may not be able to access tissue or organs located deep within the body or that are in some way obstructed. In addition, many of the instruments are limited by the way they grasp tissue, apply a suture, or recapture the needle and suture. Furthermore, many of the instruments are complicated and expensive to use due to the numerous parts and/or subassemblies required to make them function properly. Suturing remains a delicate and time-consuming aspect of most surgeries, including those performed endoscopically. 
     SUMMARY OF THE INVENTION 
     The invention generally relates to a medical device for performing a surgical procedure, such as passing a suture through tissue. Specifically, the invention relates to a suturing instrument that eliminates the need for a preassembled needle and suture and reduces or eliminates the possibility of needle loss during suturing. The suturing instrument is configured to apply sutures to approximate, ligate, or fixate tissue in, for example, open, mini-incision, trans-vaginal, or endoscopic surgical procedures. 
     The suturing instrument uses a needle housed within an elongate body member. The needle has a sharpened tip for tissue penetration and a hook-shaped distal portion for capturing a suture. When the suturing instrument is actuated, the needle is advanced out of the elongate body of the suturing instrument through tissue and into a second opening in the suturing instrument. The needle captures a suture held within the second opening of the suturing instrument in the hook-shaped distal portion of the needle. The needle is then retracted back through the tissue carrying the suture through the tissue. Alternatively, the needle can travel about the tissue, as opposed to through the tissue, thereby carrying the suture back around the tissue to ligate a vessel, for example. The suturing instrument can then be removed from the body leaving the suture intact. 
     In one aspect, the invention is directed to a suturing instrument including an elongate body member including a distal portion defining a first opening and a second opening opposing the first opening, a needle, and a needle deployment mechanism. The needle is at least partially disposed within the elongate body member and includes a hook-shaped distal portion and a tissue-penetrating tip distal of the hook-shaped distal portion. The needle deployment mechanism is coupled to a proximal portion of the needle and disposed at least partially within the elongate body member. The needle deployment mechanism moves the needle between the first and second openings. In one embodiment, the needle includes a latch movable between a first position in which the hook-shaped distal portion is open and a second position in which the hook-shaped distal portion is closed. 
     In another aspect, the invention relates to a suturing instrument including an elongate body member including a distal portion defining a first opening and a second opening that opposes the first opening, a needle at least partially disposed within the elongate body member, and a needle deployment mechanism coupled to a proximal portion of the needle and disposed at least partially within the elongate body member for moving the needle between the first and second openings. The needle includes means for penetrating tissue and means for capturing and pulling a suture from the second opening. 
     In yet another aspect, the invention relates to a suturing instrument including an elongate body member including a distal portion defining a first opening and a second opening that opposes the first opening, a needle at least partially disposed within the elongate body member, and a needle deployment mechanism coupled to a proximal portion of the needle and disposed at least partially within the elongate body member for moving the needle between the first and second openings. The needle includes a hook-shaped distal portion for pulling a suture from the second opening and a tissue-penetrating tip distal of the hook-shaped distal portion. In one embodiment, the needle includes a latch movable between a first position in which the hook-shaped distal portion opens as the needle exits the first opening and a second position in which the hook-shaped distal portion closes as the needle exits the second opening with the suture, thereby capturing the suture in the hook-shaped distal portion of the needle. 
     In various embodiments of the foregoing aspects of the invention, the body member includes a protuberance disposed on an internal surface of the first opening. The protuberance acts to open the hook-shaped distal portion of the needle by moving the latch to the first position. The body member can include a protuberance disposed on an internal surface of the second opening. The protuberance acts to close the hook-shaped distal portion of the needle by moving the latch to the second position. The body member can also include a flexible tubular member disposed distal of the protuberance. The flexible tubular member holds a suture in place. In one embodiment, the flexible tubular member is a spring. The flexible tubular member can define a first lumen and the distal portion of the suturing instrument can define a second lumen generally axially aligned with the first lumen. In addition, the distal portion of the suturing instrument can include a slot in communication with the first lumen and the second lumen. 
     In some embodiments of the suturing instrument, the latch is pivotably coupled to the needle, in others the latch is slidably disposed on the needle. In one embodiment, the distal portion of the suturing instrument has a generally C-shaped or circular profile that defines an opening for receiving tissue. The needle can be substantially straight or curved. Where the needle is curved, the latch can be disposed on an inside diameter of the needle or an outside diameter of the needle. In additional embodiments, the elongate body member can include one or more bends. The suturing instrument can be adapted to access remote organs or tissue within a body. The distal portion of the elongate body member may be rotatable relative to the remainder of the elongate body member. Further, the suturing instrument can include a handle disposed opposite the distal portion of the elongate body member. The handle can at least partially house the needle deployment mechanism. The suturing instrument can also include a suture disposed in the second opening. 
     These and other objects, along with advantages and features of the present invention herein disclosed, will become apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which: 
         FIG. 1A  is a schematic plan view of one embodiment of a suturing instrument in accordance with the invention; 
         FIGS. 1B and 1C  are schematic cross-sectional views of the proximal and distal portions of the suturing instrument of  FIG. 1A ; 
         FIG. 1D  is a schematic cross-sectional view of an alternative embodiment of the suturing instrument of  FIG. 1A ; 
         FIGS. 2A-2B ,  2 D- 2 E, and  2 G- 2 H are enlarged cross-sectional side views of the distal portion of the suturing instrument of  FIG. 1A  in various operational phases; 
         FIGS. 2C ,  2 F, and  2 I are enlarged schematic top views of the distal portion of the suturing instrument of  FIG. 1A  in various operational phases; 
         FIG. 3A  is an enlarged cross-sectional side view of the distal portion of an alternative suturing instrument in accordance with the invention; 
         FIG. 3B  is an enlarged top view of the distal portion of the suturing instrument of  FIG. 3A ; 
         FIGS. 4A-4C  are schematic representations of an alternative embodiment of a suturing instrument, in accordance with the invention, as used in various applications; 
         FIGS. 5A-5F  are schematic representations of the method of using the suturing instrument of  FIG. 4B ; 
         FIGS. 6A-6I  are schematic representations of the method of using the suturing instrument of  FIG. 4C  to place additional stitches; 
         FIGS. 7A-7C  are schematic side views of alternative needle embodiments; and 
         FIGS. 8A-8F  are schematic perspective views of another alternative needle embodiment. 
     
    
    
     DESCRIPTION 
     Embodiments of the present invention are described below. It is, however, expressly noted that the present invention is not limited to these embodiments, but rather the intention is that variations, modifications, and equivalents that are apparent to the person skilled in the art are also included. 
     A suturing instrument according to the invention can be used, for example, to access areas within the human body to ligate, fixate, or approximate tissue. The suturing instrument can throw one or more stitches intercorporeally.  FIG. 1A  illustrates the general structure of one embodiment of the present invention.  FIG. 1A  depicts a suturing instrument  100  including a handle  102 , an elongate body member  104 , and a needle deployment mechanism  110 . The suturing instrument  100  has a distal portion  106  and a proximal portion  108 . The elongate body member  104  is mechanically coupled to the handle  102  at the proximal portion  108  and the suturing components are housed in the distal portion  106  of the suturing instrument  100 . 
     The handle  102  could take a variety of forms, for example, the handle  102  could be one of the types used with Boston Scientific Corporation suturing systems, in particular the Capio® Push &amp; Catch suturing system. Generally, the needle deployment mechanism  110  extends longitudinally through the elongate body member  104  to the distal portion  106  of the suturing instrument  100 , where the needle deployment mechanism  110  is coupled to a needle. The needle deployment mechanism  110  moves the needle between a retracted position and a deployed position. One example of the needle deployment mechanism  110  is shown in greater detail in  FIGS. 1B and 1C . 
       FIGS. 1B and 1C  are cross-sectional views of the proximal portion  108  of the suturing instrument  100  ( FIG. 1B ) and the distal portion  106  of the suturing instrument  100  ( FIG. 1C ).  FIG. 1B  depicts the suturing instrument  100  including the handle  102 , the elongate body member  104 , and the needle deployment mechanism  110 . The needle deployment mechanism  110  includes a button  117 , a shaft  116 , a bearing  118 , a button end  119 , and a hole  121 . The bearing  118  rides along a cylindrical surface  105  that is formed by the inside diameter of the elongate body member  104 . A wireform  103  is inserted into the hole  121 , coupling it to the actuator button  117 . A spring  115  encircles the wireform  103 , abuts the button end  119 , and is compressed between the button end  119  and a spring washer  113 . The spring washer  113  is seated upon a center tube  107 . The center tube  107  is housed by the cylindrical surface  105  and is constrained at the distal portion  106 . A pusher wire  111  is attached to the wireform  103  by means of a weld, a coupling, adhesive or other means and is slidably disposed within a guidance sleeve  109 , the sleeve  109  being disposed within a cylindrical surface  123  formed by the inside diameter of the center tube  107 . In one embodiment, the pusher wire  111  is constructed of nitinol. Nitinol is a nickel-titanium alloy so chosen for its combination of properties that allow for bendability and high column strength when constrained. 
       FIG. 1C  is a detailed cross-sectional view of the distal portion  106  of the suturing instrument  100 , The pusher wire  111  is attached by welding or other means to a coupling  150 , which is slidably disposed within a track  152 . The coupling  150  is attached to a carrier wire  154 , which by virtue of its attachment to the coupling  150  is also slidably disposed within the track  152 . The carrier wire  154  is mechanically coupled to the needle  124  by means of a weld, a coupling, adhesive, or other means. The coupling  150  abuts a backstop washer  156  that is slidably disposed about the pusher wire  111  and is contained within a pocket  160  that includes a back wall  162 , against which the backstop washer  156  rests. The track  152  terminates distally in a pocket  164  that includes a wall  166 . A downstop washer  158  is slidably disposed about the carrier wire  154  and constrained within the pocket  164 . 
     In operation, the needle deployment mechanism  110  is actuated by pushing on the button  117 , which via the attachment to the wireform  103  which is attached to the pusher wire  111 , moves the coupling  150  along the track  152  concomitantly moving the carrier wire  154 , which slidably moves the needle  124 , thereby driving the needle  124  through tissue. As the pusher wire  111  responds to greater urging of the button  117 , the coupling  150  reaches a point in its travel along the track  152  where it pushes the downstop washer  158  such that it abuts the wall  166  of the pocket  164 . This action limits the outward travel of the carrier wire  154  to prevent overdriving and eliminate the possibility of expelling the needle  124  from the suturing instrument  100 . As the button  117  is released, the spring  115  urges the button  117  proximally, moving the pusher wire  111 , the coupling  150 , and the carrier wire  154  proximally along with the button  117  to the retracted position. 
     In an alternative needle deployment mechanism  1010  ( FIG. 1D ), the button  1012  operates a drive screw  1025  and a compression spring  1030 , which are housed in the proximal portion  1008  of the body  1004 . The button  1012  is mechanically linked to the drive shaft  1035 , which moves a gear drive  1040 , which in turn drives a gear  1045 . The gear  1045  is coupled to a link drive pin  1050 , which is itself coupled to a needle pusher  1055 . The needle pusher  1055  is in turn coupled to a needle  1024 . The pusher  1055  advances the needle  1024  out of a needle exit port  1020  and into a needle receiving port  1022 . The spring  1030  acts to retract the needle  1024  from the needle receiving port  1022  once the button  1012  is released. 
     In some embodiments, the suturing instrument  100  may include an optional articulation  114  disposed in the elongate body member  104  proximate the distal portion  106  ( FIG. 1A ). The articulation  114  facilitates the rotation and positioning of the distal portion  106  of the suturing instrument  100 . In addition, the elongate body  104  can be substantially straight or may include one or more bends. The articulation  114  and/or bend(s) can facilitate access to deep and/or difficult to reach areas within the human body. 
     The suturing instrument&#39;s component materials should be biocompatible. For example, the handle  102 , the elongate body member  104 , and portions of the needle deployment mechanism may be fabricated from extruded, molded, or machined plastic material(s), such as polypropylene, polycarbonate, or glass-filled polycarbonate. Other components, for example the needle  124 , may be made of stainless steel. Other suitable materials will be apparent to those skilled in the art. The type of material(s) used to form the suture is not critical to the present invention, as long as the material is biocompatible. The surgeon will select the length, diameter, and characteristics of the suture to suit a particular application. Additionally, the mechanical components and operation are similar in nature to those disclosed in U.S. Pat. Nos. 5,364,408 and 6,048,351, the disclosures of which are hereby incorporated herein by reference in their entireties. 
       FIGS. 2A-2I  depict enlarged views of the distal portion  106  of the suturing instrument  100  and the suturing components during various phases of operation.  FIG. 2A  is an enlarged cross-sectional view of the distal portion  106  and depicts an elongate needle  124 , a first opening or “needle exit port”  120 , and a second opening or “needle receiving port”  122 . The distal portion  106  has an essentially C-shaped profile; however, the profile can vary to suit a particular application, as long as the needle exit port  120  and the needle receiving port  122  are generally in opposition. In many instances, the open area  131  defined by the C-shaped profile receives the tissue to be sutured. The needle  124  includes a hook-shaped distal portion  126 , a tip  130  disposed distally therefrom, and an optional latch  128 . The tip  130  is configured to penetrate tissue and has an essentially conical shape; however, the shape can vary to suit a particular application and may include cutting edges. The hook-shaped distal portion  126  is disposed in a side of the needle  124  and the size and shape of the hook shape can be chosen to suit a particular application. Examples of different needles and hook-shaped distal portions are illustrated in  FIGS. 7A-7C  and  8 A- 8 F. The latch  128  is pivotably coupled to the needle  124  and opens the hook-shaped distal portion  126  in a first position and closes the hook-shaped distal portion  126  in a second position. In the embodiment shown, the latch  128  is coupled to the needle  124  via a hinge  129 . In the first position, the latch  128  is pivoted back over the body of the needle  124 , thereby opening the hook-shaped distal portion  126 . In an alternative embodiment, the latch  128  is slidably coupled to the needle  124 . The needle exit port  120  includes a latch opener  132  disposed therein for actuating the latch  128 . The needle receiving port  122  includes a latch closer  134  disposed therein for actuating the latch  128  and a suture holder  136  disposed distally from the latch closer  134 . 
     In  FIG. 2A , the suturing instrument  100  is shown in a starting position with the needle  124  positioned within the needle exit port  120  proximal of the latch opener  132 . In  FIG. 2B , the needle  124  is advanced partially out of the needle exit port  120 . As the needle  124  passes the latch opener  132 , a leading edge  133  of the latch  128  contacts the latch opener  132 , thereby pivoting the latch  128  up and opening the hook-shaped distal portion  126 . Specifically, the latch  128  is caught and lifted by the latch opener  132 . In one embodiment, the latch opener  132  extends the entire width of the needle exit port  120 . As the needle  124  continues this forward movement, the latch  128  pivots at the hinge  129  approximately 180 degrees. The hook-shaped distal portion  126  is now completely open. The needle exit port  120  includes an open area  125  above the needle  124  that serves as clearance for the latch  128  as it pivots open. The needle  124  is free to continue past the latch opener  132 , because the latch  128  can be either slightly recessed in the body of the needle  124  in the open position or the latch opener  132  can flex or rotate out of the path of the now open latch  128 . 
     In  FIG. 2C , the needle  124  is advanced approximately 50% of its full range. The latch  128  is pivoted back over the needle  124  and the hook-shaped distal portion  126  is fully exposed. While advancing the needle  124  through tissue, the tissue may prolapse into the hook-shaped distal portion  126 ; however, because the trailing edge  143  ( FIG. 2A ) of the hook-shaped distal portion  126  has no sharp edges, as shown in this embodiment, the tissue does not catch in the hook-shaped distal portion  126 . In opposition to the needle exit port  120  is the needle receiving port  122 . The needle receiving port  122  includes a latch closer  134  disposed on an interior wall thereof and extending approximately 50% of the width of the needle receiving port  122 . The needle receiving port  122  also includes a suture holder  136  that extends approximately 50% of the width of the needle receiving port  122 . The suture holder  136  is a generally flexible elongate member defining a lumen  138  extending therethrough ( FIG. 2A ). In the embodiment shown, the suture holder  136  is a spring; however, other flexible tubular structures may be used, for example, a nitinol tube. In operation, the suture holder  136  has one or more sutures  140  threaded through the lumen  138 . Further, the suture  140  runs through a second lumen  139  disposed within the distal portion  106  of the suturing instrument  100  and generally axially aligned with the lumen  138  in the suture holder  136 , thereby forming a suture bridge across the width of the needle receiving port  122 . Typically, the suture  140  is threaded through the suture holder  136  and the second lumen  139  and the ends of the suture  140  are secured at or about the proximal portion  108  of the suturing instrument  100 . 
       FIG. 2D  depicts the needle  124  entering the funnel-shaped opening of the needle receiving port  122 . The needle  124  advances past the latch closer  134  and contacts the suture holder  136 . The suture holder  136  flexes in response to the force of the advancing needle  124  and is deflected upward to allow the needle tip  130  to pass the suture holder  136 . The suture holder  136  helps to protect the suture  140  as the needle  124  passes. As can be seen in  FIG. 2E , the suture holder  136  flexes back to its original position after the needle tip  130  advances past the suture holder  136  and the suture holder  136  and suture  140  drop into the hook-shaped distal portion  126 . In this position, the suture  140  is captured within the hook-shaped distal portion  126  ( FIG. 2F ). As can be seen in  FIG. 2F , the suture holder  136  extends past the centerline  145  of the needle receiving port  122 ; however, in other embodiments, the suture holder  136  extends about or less than the distance to the centerline  145 . 
     In  FIG. 2G , the needle  124  is partially retracted from the needle receiving port  122 . The needle  124  flexes the suture holder  136  out of the hook-shaped distal portion  126 , but holds onto the suture  140  as the needle  124  moves past the suture holder  136 . At approximately the same time, the leading edge  133  of the latch  128  engages the latch closer  134  and begins pivoting back to the closed position over the hook-shaped distal portion  126 . As the needle  124  continues to retract out of the needle receiving port  122  ( FIGS. 2H and 2I ), the latch  128  is fully pivoted to the second (or closed) position to capture the suture  140  within the hook-shaped distal portion  126 . The needle receiving port  122  includes an open area  127  above the needle  124  that acts as clearance for the latch  128  as it pivots to the closed position. In addition to securing the suture  140  within the hook-shaped distal portion  126 , the closed latch  128  prevents tissue from prolapsing into the hook-shaped distal portion  126 , where it may become caught and/or torn by the hook-shaped distal portion  126 ; however, in embodiments without a latch  128 , the size and shape of the hook-shaped distal portion  126  can be chosen to reduce or eliminate the possibility of tissue damage when retracting the needle  124 . 
     As shown in  FIGS. 2H and 2I , the needle  124  is retracted through the open area  131  (and tissue if the device is so positioned) pulling the suture  140  through the open area  131  and/or tissue. After the needle  124  is fully retracted into the needle exit port  120 , the suturing instrument  100  can be removed and the suture  140  retrieved and secured. The suture  140  can be knotted internally or externally to the body. Also, the suturing instrument may include a knot pusher  146  disposed on its distal portion  106  to help position the knot relative to the tissue. Alternatively, the needle  124  can be advanced again to capture a second suture. 
       FIGS. 3A and 3B  depict an alternative embodiment of a suturing instrument  200  in accordance with the invention. The operation of the suturing instrument  200  is similar to that described with respect to  FIGS. 2A-2I , but with several differences. The latch  228  is slidably disposed on the needle  224 , as opposed to pivotably coupled to the needle  224 . As the needle  224  advances out of the needle exit port  220 , a leading edge  233  of the latch  228  engages a latch opener  232  disposed within the needle exit port  220 . The latch opener  232  slides the latch  228  rearward into a first (or open) position, thereby exposing the hook-shaped distal portion  226 . Once the latch  228  reaches the full open position, the needle  224  advances past the latch opener  232  by, for example, flexing the latch opener  232  out of alignment with the leading edge  233  of the latch  228 . 
     The needle receiving port  222  includes a latch closer  234  and a suture holder  236 . The latch closer  234  is a protuberance integrally formed with the opening of the needle receiving port  222  ( FIG. 3B ). The smooth contour of the latch closer  234  allows for easier passage of the suture  240  out of the needle receiving port  222 . The suture holder  236  is a flexible tube, such as a nitinol tube. The distal portion  206  of the suturing instrument  200  includes a slot  244  vertically aligned with the suture holder  236 . The suture holder  136  includes a slot  245  aligned with the slot  244  in the distal portion  206  of the instrument  200 . The slots  244 ,  245  facilitate loading one or more sutures  240  into the suture holder  236  by just dropping the suture  240  into the slots  244 ,  245 . As discussed hereinabove with respect to  FIGS. 2D and 2E , the suture holder  236  flexes in response to the advancing needle  224 , thereby allowing the needle  224  to capture the suture  240 . 
       FIGS. 4A-4C  depict various suturing procedures that can be performed with the suturing instrument  100  described hereinabove or an alternative embodiment of a suturing instrument  400  in accordance with the invention. The alternative embodiment of the suturing instrument  400  is similar in structure and operation to the suturing instrument  100  described hereinabove. The suturing instrument  400  includes a generally circular distal portion  406 , which houses a curved needle  424 . Other than the shape, the structure and operation of the needle  424  are similar to that described hereinabove. The hook-shaped distal portion  426  and latch  428  may be located on either the inside diameter or the outside diameter of the needle  424 . The position of the latch opener  432  and the latch closer  434  within their respective ports will be adjusted as necessary to engage the latch  428 . Alternatively, the needle  424  may not include a latch. The suturing instrument  400  depicted in  FIGS. 4A-4C  also differs from the previously described suturing instrument  100  with respect to the travel direction of the needle  424 ,  124 . Needle  124  travels away from the proximal portion  108  of the suturing instrument  100  and needle  424  travels towards the proximal portion  408  of the suturing instrument  400 . 
     In  FIG. 4A , the suturing instrument  400  is being used to perform ligation, which is a procedure where a vessel, such as an artery, is closed off. The vessel  405  is positioned within the circular distal portion  406  of the instrument  400 . The needle  424  is advanced out of the needle exit port  420 , enters the needle receiving port  422 , and is retracted back to the needle exit port  420  with the suture  440  captured within the hook-shaped distal portion  426 . The instrument  400  can then be withdrawn leaving a length of suture  440  around the vessel  405 , which can subsequently be tied off, thereby closing the vessel  405 . In this procedure, the needle  424  carries the suture  440  around the vessel  405 , but does not penetrate the vessel  405 . 
     In  FIG. 4B , the instrument  400  is being used to place a suture  440  through a single piece of tissue  415 . As seen in greater detail in  FIGS. 5A-5F , the needle  424  is driven through the tissue  415  until the needle  424  captures the suture  440  held within the needle receiving port  422  ( FIGS. 5A-5C ), as described above. Subsequently, the needle  424  is retracted back to the needle exit port  420 , thereby pulling the suture  440  through the tissue  415  ( FIGS. 5D and 5E ). The needle  424  actually pulls a loop of suture  440  through the tissue  415 , which results in two lengths of suture  440  through a common passage in the tissue  415 . The instrument  400  can then be withdrawn leaving the two lengths of suture  440  through the tissue  415  ( FIG. 5F ), which subsequently can be secured to another structure. 
     In  FIG. 4C , the instrument  400  is being used to approximate two pieces of tissue  425 . The needle  424  is driven through the two pieces of tissue  425  until the needle  424  captures the suture  440  held within the needle receiving port  422 . Subsequently, the needle  424  is retracted back to the needle exit port  420 , thereby pulling the suture  440  through the tissue  425 . The instrument  400  can then be withdrawn leaving a length of suture  440  through the tissue  425 , which subsequently can be tied off to complete the approximation. In each preceding example, the needle  424  can be advanced a second time to pull an additional two lengths of suture  140  through or around the tissue  405 ,  410 ,  425 . 
       FIGS. 6A-6I  depict the suturing instrument  400  of  FIG. 4C  being used to pass a second length of suture  440  through the tissue  425 .  FIGS. 6A-6C  and  6 F- 6 I are enlarged side views of the distal portion  406  of the suturing instrument  400 , and  FIGS. 6D and 6E  are top views of the suturing instrument  400  shown in  FIGS. 6B and 6D , respectively. In  FIG. 6A , the suturing instrument  400  is moved to a position adjacent the tissue  425  that is offset from the first suture pass. In  FIGS. 6B and 6C , the needle  424  is advanced through the tissue  425  until the needle  424  captures the suture  440  held within the suture holder  436  disposed within the needle receiving port  422 . As can be seen in  FIG. 6B , the suture is released from the hook-shaped distal portion  426  as the needle  424  is advanced and the latch  428  is opened. The needle  424  passes through a loop  441  in the suture  440  that was pulled through the tissue  425  by the first pass of the needle  424 . In the embodiment shown, the hook-shaped distal portion  426  and latch  428  are disposed on the outside diameter of the needle  424 . 
     In  FIG. 6D , the suture  440  is shown pulled from the needle receiving port  422 . This length of suture  440  was pulled out during the first pass of the needle  424 . As the needle  424  re-enters the needle receiving port  422  ( FIG. 6E ), the suture  440  is pushed aside by the needle  424  and the needle  424  deflects the suture holder  436  up and then into the hook-shaped distal portion  426 , as discussed hereinabove with respect to  FIGS. 2A-2I . As shown in  FIGS. 6F-6H , the needle  424  is retracted from the needle receiving port  422  pulling another loop of suture  440  through the tissue  425 . The second loop of suture  440  ends up within the first loop  441  ( FIG. 6G ). After the needle  424  is fully retracted into the needle exit port  420 , the suturing instrument  400  can be removed ( FIG. 6I ) and the suture  440  retrieved and secured. The suture  440  can be knotted internally or externally to the body. 
       FIGS. 7A-7C  depict various embodiments of needles that can be used in a suturing instrument in accordance with the invention. In  FIG. 7A , the needle  724  is generally elongate and linear in shape and includes a proximal portion  740  and a hook-shaped distal portion  726 . The diameter  744  of the hook-shaped distal portion  726  is smaller than the diameter  742  of the body of the needle  724 . This reduction in diameter helps to prevent tissue from prolapsing into the hook-shaped distal portion  726  when retracting the needle  724  without a latch. In  FIG. 7B , the needle  824  is generally curved and includes a proximal portion  840  and a hook-shaped distal portion  826 . The hook-shaped distal portion  826  is oriented on the inside diameter  810  of the needle  824 . The needle  924  shown in  FIG. 7C  is substantially the same as needle  824 , except the hook-shaped distal portion  924  is oriented on the outside diameter  910  of the needle  924 . In each of these embodiments, the proximal portion  740 ,  840 ,  940  can be mechanically coupled to the needle deployment mechanism  110 . 
       FIGS. 8A-8F  depict another embodiment of a needle that can be used in a suturing instrument in accordance with the invention. The needle  942  is generally elongate and linear in shape and includes a body portion  950 , a proximal tube portion  944 , a hook-shaped distal portion  960  including a needle tip  948 , and a latch  946 . The proximal tube portion  944  includes a first stop edge  952  and the hook-shaped distal portion  960  includes a second stop edge  956  ( FIG. 8B ). The latch  946  includes a proximal edge  954  and a distal edge  964  and is slidably disposed about the body portion  950  to selectively expose (open) and cover (close) at least a portion of the hook-shaped distal portion  960 . 
     In operation, as a user pushes the needle  942  through a patient&#39;s tissue (by methods previously described), friction between the needle  942  and the tissue causes the latch  946  to slide over the body portion  950  in a direction indicated by arrow  958  until the proximal edge  954  contacts the first stop edge  952  ( FIG. 8C ). This results in the hook-shaped distal portion  960  being at least partially opened to capture a suture  968  ( FIG. 8D ). After the hook-shaped distal portion  960  captures the suture  968 , the user retracts the needle  942  (by methods previously described). As the user retracts the needle  942 , friction between the needle  942  and the tissue causes the latch  946  to slide over the body portion  950  in a direction indicated by arrow  962  until the proximal edge  954  contacts the second stop edge  956  ( FIGS. 8E and 8F ). This results in the hook-shaped distal portion  960  being at least partially closed by the latch  946 . Covering the hook-shaped distal portion  960  with latch  946  helps to prevent tissue from prolapsing into the hook-shaped distal portion  960  when the user retracts the needle  942 . Alternatively, the latch  946  can be opened and closed by contacting a latch opener and a latch closer as previously described and shown in  FIGS. 2A-2I . The latch  946  has an outside diameter that is greater than any other outside diameter of the needle  942 . As a result, only the latch  946  contacts the latch opener or latch closer when the needle  942  is advanced or retracted. 
     Other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. The described embodiments are to be considered in all respects as only illustrative and not restrictive.