Abstract:
Apparatus for securing a suture thread to a region of tissue, the apparatus comprising: first and second elongate jaws respectively having first and second longitudinal axes and first and second gripping surfaces for gripping and holding a region of tissue at a tilt angle relative to the first and second axes when the jaws are closed; a channel in the first elongate jaw having a substantially straight section extending along the first longitudinal axis and a curved section that extends from the straight section to the first gripping surface for housing at least one suture anchor configured to secure a portion of a suture thread to the tissue region, and; a flexible needle inside the channel that extends along the straight section and is controllable to extract a suture anchor in the channel from the first jaw through the curved section and drive the extracted suture anchor through the tissue region to secure the suture thread.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application 61/696,186 filed on Sep. 2, 2012, the disclosure of which is incorporated herein by reference 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments of the invention relate to a suturing device suitable for use in minimal invasive surgical procedures. 
       BACKGROUND 
       [0003]    Minimal invasive surgical (MIS) procedures refer to procedures that are performed on an internal organ and/or structure, hereinafter a “target organ”, of a patient&#39;s body through small openings, often referred to as “keyholes” or “ports”, made in the skin and outer wall of the body. The procedures are conventionally referred to by a body cavity in which the target organs they are designed to treat are located. For example, MIS procedures performed on target organs in the abdominal cavity are referred to as laparoscopic procedures. If performed on a target organ in the chest, a MIS procedure may be referred to as a thoracoscopic procedure. MIS procedures performed on target organs of a joint are referred to as arthroscopic procedures. 
         [0004]    Access via a keyhole to an internal operating site at which a target organ of an MIS procedure is located, is facilitated by an access tube or tube arrangement, hereinafter referred to generically as an “access tube”, introduced into the body through the keyhole. An access tube typically comprises a cannula, trocar, and/or trocar and cannula combination, and generally has a relatively small cross-section lumen having a diameter in a range between about 5 mm and about 12 mm. The access tube is oriented so that it extends towards the operating site with a distal, open end of the access tube positioned inside the body at a location, generally near the operating site, convenient for performance of the MIS procedure. The access tube may be used to introduce into the body various MIS surgical devices used in performance of the MIS procedure so that the surgical devices have appropriate access to the target organ at the site. 
         [0005]    The MIS surgical devices generally comprise a long, small cross section shaft configured to be introduced into the access tube and have at a distal end of the shaft a tool to be used at the operating site. The tools typically introduced into a patient&#39;s body via an access tube comprise components of MIS imaging systems for viewing target organs or surgical tools for manipulating target organ tissue. Imaging system components that are introduced into the body through an access tube may include video cameras, components of endoscopes, illumination systems, ultrasound imaging systems and miniature MRI imaging devices. Surgical tools introduced into the body through an access tube may include, scissors, scalpels, tissue ablation devices, grabbers, and suturing tools. 
         [0006]    The imaging devices and surgical instruments introduced into the body through an access tube, and in particular suturing tools, often prove difficult to control with advantageous dexterity, whether controlled by a human or robotic surgeon. Typically, the MIS surgical devices require a surgeon to exhibit a relatively high degree of hand-eye coordination, which may be acquired generally only after repeated practice. 
       SUMMARY 
       [0007]    An aspect of an embodiment of the invention relates to providing an MIS suturing device for securing a suture thread to a layer of tissue inside a body with a plurality of suture anchors that are attached to the suture thread and which the suturing device drives through the tissue layer. 
         [0008]    An aspect of an embodiment of the invention relates to providing suture anchors that exhibit relatively small resistance to penetrating and being driven through a layer of tissue together with a portion of the suture thread to be secured to the tissue, but once driven through the layer of tissue may exhibit enhanced resistance to being pulled out of the tissue. 
         [0009]    An aspect of an embodiment of the invention relates to providing the suturing device with a delivery system for positioning the suture anchor at the tissue layer and driving the suture anchor and the portion of suture thread through the tissue layer to secure the suture thread to the tissue layer. 
         [0010]    In an embodiment of the invention, the suture anchors are “torpedo” shaped comprising an elongate body having a long axis and tapered front end. The torpedo shape of a suture anchor in accordance with an embodiment of the invention provides relatively low resistance to being driven through a layer of tissue, tapered end first, and with its long axis substantially perpendicular to the tissue layer. Once driven through the tissue layer, the suture anchor may be rotated so that the long axis is substantially parallel to the tissue layer. With its long axis substantially parallel to the tissue layer, the suture anchor and a portion of the suture thread attached to the anchor exhibit relatively large resistance to being pulled back out through the tissue layer. 
         [0011]    In an embodiment of the invention the suturing device comprises a set of first and second opposable elongate alligator jaws which may be closed to grip and clamp a region of the tissue layer through which a suture anchor is to be driven between respective gripping surfaces of the jaws. The gripping surfaces are located at distal ends of the elongate jaws and optionally are planar and substantially parallel when the jaws are closed. The jaws are mounted to a support barrel configured to deliver the alligator jaws to a tissue region through a trocar. 
         [0012]    The first jaw is formed having a channel that houses a needle, hereinafter a drive needle, for driving the suture anchors through the region of tissue clamped between the respective gripping surfaces of the first and second alligator jaws. The drive needle passes through each of the plurality of suture anchors along the long axes of the anchors, and the drive needle together with the plurality of suture anchors through which it passes are housed in the channel. The channel comprises a relatively long straight section that extends substantially the length of the jaw. The gripping surface of the first jaw is tilted with respect to a direction along which the straight section extends. A relatively short curved section of the channel extends from the straight section to meet the gripping surface substantially at 90°. 
         [0013]    The suturing device is controllable to shuttle the needle in and out of the channel to transport suture anchors one by one from the channel to exit the first jaw through the gripping surface of the first jaw and drive the anchor through the tissue region. The second jaw is formed having a recess that opens at the gripping surface of the second jaw for receiving the suture anchor and its associated portion of the suture thread that the drive needle drives through the tissue region. In transporting the suture anchors from the channel, the drive needle and the suture anchor that it transports bend when moving through the curved section and the needle and the anchors are configured to elastically deform to mediate the bend. 
         [0014]    Because the curved section of the channel is substantially perpendicular to the gripping region of the first and second jaws, the drive needle drives the suture anchor through the tissue region substantially parallel to the axis of the anchor along a direction substantially perpendicular to the tissue region. In an embodiment of the invention, the suture anchor is configured to be rotated by tension applied to the suture thread after the anchor is driven through the tissue region and the suturing device tensions the suture thread to rotate the suture anchor after it has been driven through the tissue region to orient the axis of the anchor substantially parallel to the tissue region. The recess in the second jaw may comprise a one way anchor stop that operates to prevent the suture anchor that it receives from being pulled back through the tissue region by tension generated in the suture thread by the suturing device and aid in rotating the suture anchor. 
         [0015]    In the discussion, unless otherwise stated, adjectives such as “substantially” and “about” modifying a condition or relationship characteristic of a feature or features of an embodiment of the invention, are understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended. Unless otherwise indicated, the word “or” in the description and claims is considered to be the inclusive “or” rather than the exclusive or, and indicates at least one of, or any combination of items it conjoins. 
         [0016]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0017]    Non-limiting examples of embodiments of the invention are described below with reference to figures attached hereto that are listed following this paragraph. Identical features that appear in more than one figure are generally labeled with a same label in all the figures in which they appear. A label labeling an icon representing a given feature of an embodiment of the invention in a figure may be used to reference the given feature. Dimensions of features shown in the figures are chosen for convenience and clarity of presentation and are not necessarily shown to scale. 
           [0018]      FIGS. 1A-1J  schematically illustrate a suturing procedure using suture anchors to secure a length of suture thread to opposite tissue edges of a tear in a tissue to sew the edges together, in accordance with an embodiment of the invention; 
           [0019]      FIG. 2  schematically shows a simplified side view of a suturing device operable to perform a suturing procedure similar to that illustrated in  FIGS. 1A-1J , in accordance with an embodiment of the invention; 
           [0020]      FIG. 3A  schematically shows alligator jaws and components of the alligator jaws comprised in the suturing device shown in  FIG. 2  that are used to grab and hold a layer of tissue and drive a suture anchor through the tissue, in accordance with an embodiment of the invention; 
           [0021]      FIG. 3B  schematically shows the alligator jaws and internal components of the alligator jaws shown in  FIG. 2A  clamped to a region of tissue prior to driving a suture anchor through the tissue, in accordance with an embodiment of the invention; 
           [0022]      FIG. 3C  schematically shows the alligator jaws and internal components of the alligator jaws shown in  FIG. 2C  clamped to a region of tissue after driving a suture anchor and a portion of suture thread through the tissue, in accordance with an embodiment of the invention; 
           [0023]      FIG. 3D  schematically shows an enlarged cross section view of components of the alligator jaw used to regulate driving suture anchors one by one through a region of tissue, in accordance with an embodiment of the invention; and 
           [0024]      FIGS. 4A-8C  schematically illustrate control and operation of a suturing device in driving a suture anchor through a region of tissue in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    In the detailed description below the kinematics of a procedure for suturing a layer of tissue to close a tear in the tissue layer, in accordance with an embodiment of the invention are discussed with reference to  FIGS. 1A-1J . The figures illustrate puncturing the tissue, one by one with each of a plurality of suture anchors mounted to a same flexible drive needle to secure a suture thread to the tissue and close the tear in accordance with an embodiment of the invention. A suturing device for implementing a procedure similar to that shown in  FIGS. 1A-1J  is shown in  FIG. 2  and discussed with reference to the figure. Features of the suturing device shown in  FIG. 2  and mechanical components optionally comprised in a suturing device in accordance with an embodiment of the invention, are shown in  FIGS. 3A-3F  and discussed with reference to the figures. Operation of the suturing device and cooperation of its mechanical parts to implement a procedure similar to that shown in  FIGS. 1A-1J  are discussed with reference to  FIGS. 4A-8C . 
         [0026]      FIGS. 1A-1J  schematically illustrate using suture anchors  20  mounted to a flexible drive needle  40  that passes through the suture anchors to secure a length of suture thread  60  to opposite tissue regions  70  and  80  of a tear  91  in a tissue layer  90  to sew the opposite tissue regions together, in accordance with an embodiment of the invention. Tissue region  70  has top and bottom surfaces  71  and  72  respectively and tissue region  80  has top and bottom surfaces  81  and  82  respectively. A side of tissue region  70  facing top surface  71  may be referred to as a top side  71  of the tissue region and a side of tissue region  70  may be referred to as a bottom side  72  of the tissue region. Similarly, top and bottom sides of tissue region  80  may be referred to as top and bottom sides  81  and  82  respectively. 
         [0027]      FIG. 1A  shows a plurality of suture anchors  20  threaded, butted front to back, on drive needle  40  poised above top surface  71  of tissue region  70  immediately prior to driving a first suture anchor  20 , referred to as a “lead” suture anchor and distinguished by a reference numeral  20 - 1 , through tissue region  70 . Suture anchors  20 , located behind lead suture anchor  20 - 1  are distinguished by numerals  20 - 2 ,  20 - 3  . . .  20 -N, where the number following the dash in each numeral corresponds to a position behind lead suture anchor  20 - 1  of the suture anchor that the numeral distinguishes. “N” is a number of the plurality of suture anchors mounted to drive needle  40 . An enlarged cross section view of lead suture anchor  20 - 1  is shown in an inset  100 . 
         [0028]    Suture anchors  20  optionally comprise an elongate torpedo shaped hollow body  21  having a tapered front end  22  a non-tapered back end  30 , a long axis  23 , and a lumen  24  through which drive needle  40  passes parallel to the long axis. Body  21  may have any of various external cylindrical shapes. Body  21  may for example be circularly cylindrical or elliptically cylindrical. Axis  23  and lumen  24  are shown for lead suture anchor  20 - 1  in inset  100 . Lumen  24  is optionally formed as a two chamber lumen having a small cross section front chamber  25  and a larger cross section back chamber  26 . An annular ridge  27  is formed where chambers  25  and  26  meet. Each suture anchor  20  optionally comprises a fin  28  attached to anchor body  21 . Fin  28  is formed having a hole  29  through which suture thread  60  passes. 
         [0029]    Except for possibly lead suture anchor  20 - 1 , suture thread  60  is free to slide in hole  29  of fin  28 . Optionally, a lead end  61  of suture thread  60  is formed having an anchor guard, schematically represented by a sphere  62 , that prevents lead suture anchor  20 - 1  from sliding off the suture thread. By way of example, anchor guard  62  may comprise a knot tied in lead end  61  of suture thread  60  or a bead formed at the lead end. The bead may be formed by heating lead end  61  of suture thread  60  to melt material in the lead end so that it forms a bead. In an embodiment of the invention lead suture anchor  20 - 1  may be fixed to lead end  61  of suture thread  60 , for example by crimping fin  28  to the suture thread, to prevent the lead suture anchor from sliding off suture thread  60 . 
         [0030]    Drive needle  40  has a shaft  41  formed from a suitable elastic material such as stainless steel or nitinol and a pointed tip  42  suitable for puncturing tissue. Optionally, drive needle  40  comprises at least one elastic “splay spur”  43  which is configured to splay out elastically away from shaft  41  so that an end of the at least one splay spur facing toward tip  42  of drive needle  40  displaces away from the shaft. At least one splay spur  43  may be drawn into large cross section chamber  26  of lumen  24  through small chamber  25  by translation of drive needle  40  along axis  23  “backwards” in a direction indicated by an arrow  101  in inset  100 , pointing away from tapered front end  22  of suture anchor  20 - 1 . Once drawn into large cross section chamber  26 , at least one splay spur  43  may splay out elastically to “catch” on ridge  27 . When at least one splay spur  43  is caught on ridge  27 , translation of drive needle shaft  41  along axis  23  in a direction towards tapered end  22  of lead suture anchor  20 - 1  couples the suture anchor to drive needle shaft  41  so that the suture anchor translates with the needle shaft. Optionally, drive needle  40  has a raised lip  44  near tip  42  of the drive needle that operates to prevent a suture anchor  20  from easily sliding forward off the tip of the drive needle. 
         [0031]    In  FIG. 1B  drive needle  40  is pushed “forward” carrying with it lead suture anchor  20 - 1 , which is locked to the drive needle by at least one splay spur  43  ( FIG. 1A ), to penetrate and drive the lead suture anchor through tissue region  70 . In driving lead suture anchor  20 - 1  through tissue region  70 , flexible drive needle  40  bends so that the lead suture anchor may be driven through tissue region  70  at an advantageous “penetration angle”. In an embodiment of the invention, suture anchors  20  are configured to bend with drive needle  40  when the drive needle bends to drive the suture anchor through a region of tissue. 
         [0032]    Penetration angle of a suture anchor  20  being driven through a tissue region may be an angle that axis  23  of the suture anchor makes with a plane of the tissue region. Optionally, the plane of the tissue region is a surface of the tissue region that the suture anchor first breaches when penetrating the tissue region. In  FIG. 1B  penetration angle of suture anchor  20 - 1  is an angle that axis  23  of suture anchor  20 - 1  makes with surface  71  of tissue region  70 . In an embodiment of the invention the penetration angle is advantageously equal to about 90° so that in  FIG. 1B  axis  23  is substantially perpendicular to surface  71 . Because lead end  61  of suture thread  60  comprises anchor guard  62 , or lead suture anchor  20 - 1  is fixed to the suture thread, when lead suture anchor  20 - 1  is driven through tissue region  70  the lead suture anchor carries with it a portion of suture thread  60 . 
         [0033]    Methods and apparatus for pushing drive needle  40  forward to carry a single suture anchor, such as lead suture anchor  20 - 1 , of the plurality of suture anchors  20  mounted to drive needle  40  and bend drive needle  40  to orient a suture anchor  20  at an advantageous penetration angle are discussed below. 
         [0034]    Following penetration of lead suture anchor  20 - 1  through tissue region  70 , drive needle  40  is retracted out of the lead suture anchor and out of tissue region  70  to leave lead suture anchor  20 - 1  on bottom side  72  of the tissue region and couple to next suture anchor  20 - 2  threaded on drive needle  40 .  FIG. 1C  schematically shows drive needle  40  retracted from lead suture anchor  20 - 1  and tissue region  70  before it is sufficiently retracted to couple at least one splay spur  43 , and thereby the drive needle, to suture anchor  20 - 2 . In the retracted state shown in  FIG. 1C  at least one splay spur  43  is visible and shown greatly enlarged in an inset  104 .  FIG. 1D  schematically shows drive needle  40  after it has been sufficiently retracted to couple to suture anchor  20 - 2 . 
         [0035]    As noted above, raised lip  44  ( FIG. 1A ) prevents a suture anchor  20 , such as lead suture anchor  20 - 1 , from easily sliding off tip  42  of the drive needle. However, an amount by which lip  44  is raised is not sufficient to prevent drive needle  40  from being retracted from a suture anchor  20  after the suture anchor has been driven through a tissue region by a suturing device in accordance with an embodiment of the invention. In an embodiment of the invention, the suturing device, as discussed below, comprises a “one-way anchor stop” that operates to prevent a suture anchor from being pulled back through a tissue region by retraction of drive needle  40  after the suture anchor has been driven through the tissue region. 
         [0036]    Following retraction of drive needle  40  as shown in  FIG. 1D , suture thread  60  is drawn taut. Drawing the suture thread taut applies force to fin  28 , which because the fin is located on a side of lead suture anchor  20 - 1 , generates a torque. The torque operates to rotate lead suture anchor  20 - 1  and orient axis  23  parallel to bottom surface  72  of tissue region  70  and press elongate body  21  of the suture anchor substantially parallel to the bottom surface as schematically shown in  FIG. 1E . With lead suture anchor  20 - 1  rotated parallel and pressed to bottom surface  72 , lead suture anchor  20 - 1  is relatively difficult to dislodge and pull out through tissue region  70  and the lead suture anchor securely holds a portion of suture thread  60  on bottom side  72  of tissue region  70 . 
         [0037]    After securing a portion of suture thread  60  on bottom side  72  of tissue region  70 , drive needle  40  is positioned over tissue region  80  as schematically shown in  FIG. 1F  to puncture tissue region  80  and drive suture anchor  20 - 2  together with a portion of suture thread  60  attached to suture anchor  20 - 2  through the tissue region.  FIG. 1G  schematically shows suture anchor  20 - 2  after it has been driven through tissue region  80 . Following driving suture anchor  20 - 2  through tissue region  80 , drive needle  40  is retracted to couple to suture anchor  20 - 3  as schematically shown in  FIG. 1H  and suture thread  60  is drawn taut to rotate suture anchor  20 - 2  and secure the suture anchor pressed to bottom surface  82  of tissue region  80 .  FIG. 1I  schematically shows suture anchor  20 - 2  after it has been rotated and pressed to bottom surface  82 . 
         [0038]    Because suture thread  60  is free to slide through fin  28  of suture anchor  20 - 2 , drawing suture thread  60  taut draws tissue region  80  to tissue region  70  and closes a portion of tear  91  in the vicinity of suture anchors  20 - 1  and  20 - 2  as schematically shown in  FIG. 1I . Drive needle  40  is then optionally repositioned over tissue region  70  as schematically shown in  FIG. 1J  to drive suture anchor  20 - 3  through tissue region  70  and secure another portion of suture thread  60  to tissue region  70 . Drive needle  40  is then optionally repositioned over tissue region  80  to drive suture anchor  20 - 4  through the tissue region, draw taut suture thread  60  and close another portion of tear  91 . The process is repeated, alternately driving a suture anchor  20  and a portion of suture thread  60  attached to the suture anchor through tissue region  70  and tissue region  80  and drawing the suture thread taut to close additional regions of tear  91  until the tear is closed and/or a last suture anchor  20  is secured to tissue region  70  or tissue region  80 . Following driving a last suture anchor  20  (optionally a suture anchor  20 -N) into one of tissue regions  70  or  80  suture thread  60  is optionally tied to the tissue regions using a conventional knotting procedure. 
         [0039]      FIG. 2  schematically shows a simplified side view of a suturing device  200  configured to perform a suturing procedure similar to that shown in  FIGS. 1A-1J  in accordance with an embodiment of the invention. Suturing device  200  optionally comprises a manually operated control handle  202  connected to a relatively long thin support barrel  300  comprising a pair  400  of opposable alligator jaws  410  and  420 , collectively referred to as alligator jaws  400 . Opposable alligator jaws  410  and  420  are controllable by operation of control handle  202  to grab and hold a layer of tissue and drive a suture anchor  20  from alligator jaw  420  through the tissue layer to alligator jaw  410 , in accordance with an embodiment of the invention. Support barrel  300  is dimensioned to be inserted into an MIS access tube (not shown) to position alligator jaws  400  at an internal site in a patient&#39;s body where they are to be used. Handle  202  optionally has first and second triggers  204  and  206  that are operated to control functions of suturing device  200 . Details of control handle  202  and control of functions of suturing device  200  are discussed below with reference to  FIGS. 4A-8C . 
         [0040]      FIG. 3A  schematically shows an enlarged view of alligator jaws  410  and  420  and a portion of support barrel  300  near a distal end  302  of the support barrel to which the jaws are connected. Dashed lines are used to indicate features which are to be considered transparent to show internal components of the features or components housed in the features. 
         [0041]    Alligator jaw  420 , also referred to as a “drive needle jaw  420 ”, is formed having a suture anchor feed channel  422  that houses drive needle  40  and suture anchors  20  shown in  FIGS. 1A-1I , mounted on the drive needle. Suture anchor feed channel  422  extends the length of drive needle jaw  420  to a surface  430  at which the anchor feed channel has an opening  43  and may have any suitable cross section that accommodates drive needle  40  and suture anchors  20 . For example, suture anchor feed channel may have a substantially circular, elliptical, tear or egg shaped cross section. Drive needle  40 , is controllable to shuttle back and forth in anchor feed channel  422  into and out of drive needle jaw  420  through opening  432  of surface  430  to carry suture anchors  20  one by one together with portions of suture thread  60  to which they are coupled out of drive needle jaw  420  and drive the anchors through a tissue layer. A drive needle push rod  433  connected to the drive needle and housed in support barrel  300  is controlled by control handle  202  ( FIG. 2 ) to control motion of drive needle  40 . 
         [0042]    In an embodiment of the invention, drive needle face  430  is tilted with respect to a longitudinal axis represented by a dotted line  434  of drive needle jaw  420 , and suture anchor feed channel  422  comprises a curved section  423  that meets opening  432  on needle face surface  430 . An angle, hereinafter a “tilt angle” of drive needle face  430  may be defined by an acute angle α that a normal, indicated by an arrow  435 , to surface  430  makes with longitudinal axis  434 . At opening  432  a tangent (not shown) to curved section  423  is substantially perpendicular to drive needle face  430 . As a result, when drive needle  40  shuttles back and forth to sequentially drive suture anchors  20  through a region of tissue it exits and enters drive needle jaw  420  substantially perpendicular to drive needle face  430 . To negotiate curved section  423  of suture anchor feed channel  422 , drive needle  40  and suture anchors that the drive needle transports through curved section  423  are configured in accordance with an embodiment of the invention to resiliently bend at a minimum radius of curvature that characterizes curved section  423 . 
         [0043]    By way of a non-limiting numerical example, in an embodiment of the invention, drive needle  40  may have a circularly cylindrical body  41  having a diameter between about 0.15 and about 0.6 mm and may be formed from a resilient material such as stainless steel or nitinol. In an embodiment of the invention body  41  has a diameter equal to about 0.25 mm. 
         [0044]    Body  21  of a suture anchor  20  is optionally circularly cylindrical, having an outer diameter between about 0.3 mm and about 1.5 mm and length from about 2.5 mm to about 7 mm. In an embodiment of the invention, body  21  has a diameter equal to about 0.85 mm and length equal to about 4 mm. For a 0.85 mm diameter body, fin  28  may protrude about 0.5 mm from the body. Small chamber  25  of lumen  24  is optionally circular having a diameter between about 0.1 and about 0.6 mm. In an embodiment of the invention, chamber  25  has a diameter equal to about 0.24 mm. Large chamber  26  is optionally circular having a diameter between about 0.3 mm and about 1.3 mm. In an embodiment of the invention large chamber  26  has a diameter equal to about 0.58 mm. A suture anchor  20  in accordance with an embodiment of the invention may be formed from a resilient material such as Teflon, or an elastomer, such as polyurethane, styrene-ethylene-butadiene-styrene (SEBS), or silicon. 
         [0045]    Suture anchor feed channel  422  has any cross section shape suitable for accommodating drive needle  40  and suture anchors  20 . In an embodiment of the invention the cross section has a maximum dimension between about 0.8 mm and about 2.5 mm. To accommodate a suture anchor having a circularly cylindrical body  21  and fin  28  protruding from a side of the body, suture anchor channel  422  may have a “Russian doll” shape formed substantially by a perimeter around a shape formed by a large circle and a small circle intersecting. To accommodate a suture anchor body having diameter 0.85 mm and fin  28  protruding 0.45 mm the large and small circles may have diameters equal to about 0.9 and 0.7 mm and a maximum dimension along a line joining the centers of the circles equal to about 1.33 mm. Curved section  423  of channel  422  may have a minimum radius of curvature between about 2.5 mm and about 4.5 mm. In an embodiment of the invention curved section has a radius of curvature equal to about 3.5 mm. Optionally, angle α is greater than or equal to about 30°. In an embodiment of the invention, a is greater than or equal to about 45°. Optionally a is greater than or equal to about 60°. 
         [0046]    In an embodiment of the invention, alligator jaws  400 , when closed can be passed through a trocar having an internal diameter less than or about equal to 12 mm. Optionally the closed alligator jaws are passable through a trocar having an internal diameter less than or about equal to 9 mm. In an embodiment, closed alligator jaws  400  can be passed through a trocar having an internal diameter less than or equal to about 5 mm. 
         [0047]    Alligator jaw  410 , also referred to as backstop jaw  410 , is optionally a rigid extension of support barrel  300  and operates as a “backstop” to drive needle jaw  420  when alligator jaws  410  and  420  are closed to clamp a region of tissue being sutured using suturing device  200  and to counter forces generated by driving a suture anchor  20  from drive needle jaw  420  through the tissue region. 
         [0048]    Drive needle jaw  420  is rotatably connected to support barrel  300  so that it may be rotated away from and towards backstop jaw  410  about a swivel pin  424  at distal end  302  of support barrel  300  to open and close alligator jaws  410  and  420  and grab and clamp a tissue layer through which drive needle  40 , drives a suture anchor  20 . A push rod  426  housed in support barrel  300  controls position of drive needle jaw  420 . Push rod  426  is optionally connected to drive needle jaw  420  by a swivel pin  427  and translation of the push rod in directions indicated by arrows  428  and  429  respectively rotates drive needle jaw  420  away from and toward backstop jaw  410 . Push rod  426  is controlled by operation of control handle  202 , details of which are discussed below. 
         [0049]      FIG. 3B  schematically shows alligator jaws  410  and  420  closed and grabbing a tissue layer  500  so that drive needle  40  can drive a suture anchor  20  with its associated portion of suture thread  60  from needle drive jaw  420  through the tissue layer. 
         [0050]    Backstop jaw  410  optionally comprises an anchor backstop  411  having a recess  412 , and a backstop surface  413 . Recess  412  is shown in an enlarged perspective view of anchor backstop  411  in an inset  110 . Backstop surface  413  is tilted by a tilt angle  13  with respect to a longitudinal axis  436  of backstop jaw  410 . Tilt angle  13  is an acute angle that a normal, represented by an arrow  437  to backstop surface  413  makes with longitudinal axis  436 . Optionally, tilt angle  13  is substantially equal to tilt angle α. 
         [0051]    When alligator jaws  410  and  420  are closed to grab and hold a region of tissue through which suturing device  200  ( FIG. 2 ) drives a suture anchor  20  and its associated portion of suture thread  60 , the tissue region is clamped between backstop surface  413  and drive needle face surface  430 , and suture anchor  20  is received in recess  412  of anchor backstop  411 . Backstop surface  413  and drive needle face surface  430  may be referred to as “gripping” or “clamping” surfaces. In an embodiment of the invention, anchor backstop  411  comprises a one way anchor stop that operates to prevent the suture anchor that it receives in recess  412  from being pulled back through the tissue region by retraction (schematically shown in, and discussed above with reference to  FIGS. 1C and 1D ) of drive needle  40  after the suture anchor has been driven through the tissue region. 
         [0052]      FIG. 3C  schematically shows tissue layer  500  clamped between backstop surface  413  and drive needle surface  430  of alligator jaws  410  and  420  after a suture anchor  20  has been driven through tissue layer  500  and before drive needle  40  is retracted from the suture anchor and the tissue layer. 
         [0053]    In an embodiment of the invention, a one way anchor stop comprises a spring clip  415  through which a suture anchor  20  passes after being driven through the tissue region. The spring clip has arms  416  that are elastically pushed apart by the tapered front end  22  and body of suture anchor  20  during passage of the suture anchor through the spring clip. After the suture anchor has passed through spring clip  415 , arms  416  snap back and “lock” behind the non-tapered back end  30  ( FIG. 1A ) of the suture anchor to prevent the suture anchor from being pulled out of the tissue through the spring clip. 
         [0054]    By tilting drive needle face surface  430  and backstop surface  413 , providing feed channel  422  with curved section  423  and configuring, drive needle  40  and suture anchors  20  to negotiate the curved section, alligator jaws  410  and  420  may be made relatively long up to 7 cm to enable convenient gripping of a region of tissue and driving a suture anchor  20  through the region substantially perpendicular to the tissue. In particular, the relatively long alligator jaws  410  and  420  may enable gripping and suturing a tissue region using suture anchors  20  at relatively large distances from an edge of the tissue. 
         [0055]    Shuttling drive needle  40  in and out of drive needle jaw  420  along feed channel  422  to pick up and drive suture anchors  20  one by one through a tissue layer is controlled by drive needle push bar  433  ( FIG. 3A ,  FIG. 3C ) and by a feed spring  450  ( FIGS. 3B-3C ), and front and back anchor stops  452  and  454  housed in drive needle jaw  420 . A schematic enlarged cross section view of front and back anchor stops  452  and  454  is shown in  FIG. 3D  together with drive needle  40  coupled to a suture anchor  20  by splay spurs  43 . 
         [0056]    Push bar  433  is connected to control handle  202  and the control handle is operated to move the push bar back and forth in directions indicated by arrows  461  and  462 . Moving push bar  433  back and forth in directions indicate by arrows  461  and  462  shuttles drive needle respectively out from and back into drive needle jaw  420 . Feed spring  450  spring loads suture anchors  20  so that as each suture anchor  20  is removed from feed channel  422  by motion of drive needle  40  out from the feed channel to be driven through a layer of tissue, the remaining suture anchors  20  are pushed forward along drive needle  40  until, as schematically shown in  FIG. 2D , a first suture anchor  20  of the remaining anchors passes back anchor stop  454  and is subsequently stopped by front anchor stop  452 . 
         [0057]    Front anchor stop  452  optionally comprises a bushing  470  optionally spring loaded by a resilient element represented by a spring  471 . Bushing  470  lodges against tapered front end  22  of the first suture anchor to stop forward motion of the suture anchor in feed channel  422  until drive needle  40  coupled to the suture anchor by splay spurs  43  is pushed forward to move out of feed channel  422  and drive needle jaw  420 . Back anchor stop  454  comprises a leaf spring  472  that catches on back end  30  of suture anchor  20  when the back end passes the leaf spring. Back anchor stop  454  operates to prevent suture anchor  20  stopped between front anchor stop  452  and back anchor stop  454  displacing backward when drive needle  40  is retracted into drive needle jaw  420  to pick up and drive another suture anchor  20  through a region of tissue after having driven a previous suture anchor  20  through the tissue. 
         [0058]      FIGS. 4A   8 C schematically show components of control handle  202  comprised in suturing device  200 , and operation of the components in performing various steps involved in securing a suture thread  60  to a region of tissue using suture anchors  20 , in accordance with an embodiment of the invention. 
         [0059]      FIG. 4A-4C  schematically shows internal features of control handle  202  of suturing device  200  when alligator jaws  400  are open before grabbing a region of tissue  500 , the first time to secure a suture thread to the region. Tissue region  500  is schematically shown positioned on backstop  411  of alligator backstop jaw  410 . 
         [0060]    In an embodiment of the invention, trigger  204  of control handle  202  is coupled to drive needle push rod  433  by a rack and pinion arrangement in which a rack  210  is connected to drive needle push rod  433  and trigger  204  is coupled to rack  210  by a gear teeth  212 . A bias spring  214  optionally rotates trigger  204  to a forward position and therefore translates rack  210  to a backward position which, unless trigger  204  is pulled, pulls drive needle push rod back and maintains drive needle  40  retracted into drive needle jaw  420 . Trigger  206  is connected to push rod  426 , which controls attitude of drive needle jaw  420  to control opening and closing alligator jaws  400 . Optionally, a bias spring  216  pushes trigger  206  to a forward position, which unless trigger  206  is pulled, pushes push rod  426  forward, rotating drive needle jaw  420  away from backstop jaw  410  and opening the jaws. In an embodiment of the invention control handle  202  comprises a suture feed that provisions suture thread  60  to suture anchors  20  and is controllable to maintain a desired tension in the suture thread. Optionally, the suture feed comprises a reel  220  on which the suture thread is wound and a system of sheaves  222  that direct the suture thread to barrel  300  and suture anchors  20  ( FIGS. 5B and 5C ). In an embodiment a spring loaded brake shoe  224  is coupled to reel  220  to control tension in suture thread  60 .  FIGS. 4B and 4C  schematically show features of suturing device  200  for the state of triggers  204  and  206  shown in  FIG. 4A . 
         [0061]      FIGS. 5A-5C  schematically shows features of suturing device  200  shown in  FIGS. 4A-4C  when trigger  206  is pulled to rotates drive needle jaw  420  to backstop jaw  410  close the jaws to clamp and hold tissue region  500 . 
         [0062]      FIG. 6A  schematically shows features of suturing device  200  when after trigger  206  is pulled to clamp tissue region  500 , trigger  204  is pressed to translate rack  210  forward (towards support barrel  300 ), and thereby push drive needle push rod  433  forward to push drive needle  40  out of drive needle jaw  420  and drive a suture anchor  20  through tissue region  500 .  FIGS. 6B and 6C  show suture drive needle  40  driven through tissue region  500 . 
         [0063]    In  FIG. 7A  trigger  204  is released. Bias spring  214  rotates trigger  204  clockwise (in  FIG. 7A ) to its front position translating rack  210  backwards and extracting drive needle  40  from tissue layer  500  and suture anchor  20  driven through tissue layer  500 , and retracting the drive needle into drive needle jaw  420 .  FIGS. 7B and 7C  schematically show enlarged portions of suturing device  200  from which it may be seen that drive needle  40  present in suture anchor  20  in  FIG. 6B  and  FIG. 6C  is absent from the suture anchor in  FIGS. 7B and 7C . 
         [0064]    After retraction of drive needle  40  schematically illustrated in  FIGS. 6A-6C  trigger  206  is released and the trigger is pushed forward by bias spring  216  rotating drive needle jaw  420  away from backstop jaw  410  as schematically shown in  FIG. 8A . In rotating away from backstop jaw  410 , as a result of tension in suture thread  60  generated by forces applied by spring loaded brake shoe  224  to suture reel  220 , drive needle jaw takes up slack in suture thread  60  between suture anchor  20  driven through tissue layer  500  and applies force to fin  28  of the suture anchor.  FIGS. 8B and 8C  schematically show drive needle jaw  420  rotated away from backstop jaw  210  and “pulling” suture thread  60  to take up slack in, and tension, the suture thread. The force generates a torque that rotates the suture anchor so that it is oriented with respect to tissue layer  500  similar to the orientation of suture anchor  20 - 1  with respect to tissue layer  70  shown in  FIG. 1E . 
         [0065]    In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb. 
         [0066]    Descriptions of embodiments of the invention in the present application are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments utilize only some of the features or possible combinations of the features. Variations of embodiments of the invention that are described, and embodiments of the invention comprising different combinations of features noted in the described embodiments, will occur to persons of the art. The scope of the invention is limited only by the claims.