Abstract:
An apparatus for delivering bioabsorbable fasteners of the type having two cannulated legs to secure the two sides of an incision in tissue comprises a housing containing a magazine with one or more fasteners positioned on a reciprocally movable fastener support. Needle guide tubes and the legs of the front-most fastener are in slidable contact with at least one alignment surface configured to axially align them. An actuator is operated by a user to move two needles within the needle guide tubes to insert each needle into a cannulated leg. A timing lever acts on the fastener support in concert with the actuator movement to remove support of the front-most fastener after the needles are inserted. The needle guide tubes transfer force to the fastener, to push it out of the magazine and along a path through the center of a bifurcated foot, to insert it into the tissue.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to sequentially deploying a plurality of bioabsorbable fasteners into tissue to secure two sides of an incision or cut in the skin or other tissue of a patient. 
       BACKGROUND OF THE INVENTION 
       [0002]    There are many examples of surgical staplers which deliver staples one at a time. Most of these deliver traditional metal staples which rely on the strength of the staple to pierce the tissue and to hold the tissue surfaces together. Hence the typical surgical stapler engages the first staple at the front of a linear array of staples, and pushes it into the tissue while bending it over an anvil. Once the staple is bent into position, the tissue surfaces that are being held cannot un-bend the metal staple. One of the disadvantages of the metal staple is that it must have a portion that remains exposed through the skin surface in order to allow a medical professional to remove the fastener once biological healing is complete. This exposed portion is unsightly, and the puncture points where the fastener enters the skin, have a risk of infection. 
         [0003]    To address the disadvantages of metal staples, various inventors have proposed fasteners made of bioabsorbable materials which can be placed below the surface of the skin. This subcuticular skin closure avoids punctures through the epidermis, and does not require follow-up removal of the staples. Such a fastener is described in U.S. Pat. No. 6,726,705 to Peterson et al, as a “Mechanical Method and Apparatus for Bilateral Tissue Fastening”. A product based on this patent, the INSORB® Subcuticular Skin Stapler, has been commercialized by Incisive Surgical of Plymouth, Minn. The fastener deployed by the INSORB device is significantly thicker in cross section than a metal staple to enable the plastic material to be strong enough to maintain the traditional “U” shape of a staple during the healing process. This added bulk is undesirable as it takes longer to be absorbed by the body. Also the head of the INS ORB stapler must be inserted within the incision to deploy the fastener. This means that the user has poor visibility as to the placement of the fastener and that the device cannot be used on small incisions such as those employed in increasingly popular minimally invasive surgery. 
       SUMMARY OF THE INVENTION 
       [0004]    An objective of the present invention is to provide a stapler apparatus, that is easily operated by a user, to aid in the insertion of one or more bioabsorbable fasteners for closing incisions, including small incisions such as ones that are less than 10 mm long. Another objective of the present invention is to provide good visibility to the operator of the site where the fastener will be inserted. Yet another objective is to provide a stapler loadable, or preloaded, with multiple fasteners stored in a magazine or cartridge, where the stapler is able to deploy the fasteners one at a time. A sufficient number of fasteners can be loaded or preloaded, or different configurations of the stapler can be provided, to close long as well as short incisions. Another objective of the present invention is to provide a locking mechanism that prevents fasteners from being accidentally discharged during shipment or handling prior to intentional use. An additional objective is to provide a stapler with a safety mechanism that prevents the needles from being exposed after the last fastener is delivered by the stapler. 
         [0005]    The present application and invention is directed to a surgical stapling apparatus able to deploy fasteners of the type described by Danielson et. al. in U.S. patent application publication number 2009/0206127 A1 “Tissue Fasteners and Related Insertion Devices, Mechanisms, and Methods” (hereinafter “Danielson”), which is incorporated herein by reference in its entirety. The present invention relates to a new and innovative delivery device that is not disclosed in Danielson and that can be used by an operator (such as a surgeon or other medical professional) to insert into tissue of a patient (such as a human or other mammal) the bioabsorbable fasteners disclosed in Danielson and to insert them generally in accordance with the insertion procedure/steps set forth in Danielson. Other types of bioabsorbable fasteners may also be used with and deployed by the disclosed apparatus. 
         [0006]    The present invention relates to a mechanical apparatus for inserting needles into cannulated legs of a bioabsorbable fastener. The apparatus comprises a housing which orients and constrains other elements of the apparatus. Extending from the proximal end of the housing is an actuator that may be operated by the thumb of the user such that pressing the actuator into the housing causes a fastener, carried on needles and pushed by components operably connected to the actuator, to be deployed from the distal end of the housing. The housing further contains a magazine with a plurality of fasteners positioned on a reciprocally movable fastener support and a timing lever, which acts on the fastener support to move it and release each fastener one-by-one after the needles are inserted into the cannulated legs. 
         [0007]    As the user continues to push the actuator, the needles and fastener exit the distal end of the housing and deliver the fastener between the two sides of a bifurcated foot over which the two sides of a patient&#39;s incision or cut have been positioned. The user has complete visibility of the fastener as it exits the housing before it enters the tissue, and thus can adjust the position of the stapler or tissue to precisely direct the fastener to the desired target. With manual control of speed and force, the user can deploy the fastener into the tissue such that the two legs of the fastener are inserted into the two sides of the incision. Upon releasing the actuator, it is returned by a spring to its starting position, thereby retracting the needles and leaving the fastener deployed beneath the surface of the tissue. 
         [0008]    In order to reliably guide the needles into the cannulated legs of each fastener, the apparatus further comprises needle guide tubes made of cylindrical tubes which have an outside diameter similar in size to the outside diameter of the legs of the fastener. The distal ends of these needle guide tubes are slideably held by shaped features at the front of the magazine (“huggers”) which simultaneously contact and align the needle guide tubes and the legs of the fastener as the needles exit the needle guide tubes and enter the fastener legs. The huggers reduce the impact of normal manufacturing and assembly imperfections and tolerances, and allow the critical step of inserting the needles into the cannulated legs of the fasteners to be achieved reliably, and repeatedly, for each and every fastener loaded (or preloaded) into the apparatus. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    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: 
           [0010]      FIG. 1A  shows a perspective view of the assembled apparatus of the present invention with safety lock installed; 
           [0011]      FIG. 1B  shows the apparatus of the present invention with safety lock removed and actuator depressed fully to deliver a fastener; 
           [0012]      FIG. 2A  shows components of the present invention with the left housing shell  20  removed to illustrate the components inside; 
           [0013]      FIG. 2B  shows the right housing shell of  FIG. 2A  with all components removed; 
           [0014]      FIGS. 3A through 3D  show the sequence of positions of selected parts of the apparatus at different steps during the deployment of a fastener; 
           [0015]      FIG. 4  shows a partially exploded perspective view of the magazine and cap and selected components normally assembled together; 
           [0016]      FIG. 5  shows a cross section of the magazine and cap taken along the A-A′ plane of  FIG. 4  and including non-sectioned views of some internal components; 
           [0017]      FIG. 6A  shows a perspective view of the fastener support with the front-most fastener and guide tube support with needle guide tubes and timing lever positioned at the start of delivery of a fastener; 
           [0018]      FIG. 6B  shows the same perspective as  FIG. 6A  with the components positioned at an intermediate point in the delivery of the front-most fastener; and 
           [0019]      FIG. 7  shows a cross section of the components of  FIG. 4  taken along the B-B′ plane, positioned at the start of delivery of a fastener as shown in  FIG. 6A . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1A  illustrates a perspective view of an apparatus  10  for inserting bioabsorbable fasteners to secure the two sides of an incision in tissue as illustrated in FIG. 1 and FIG. 2 of Danielson (U.S. patent application publication number 2009/0206127 A1). For purposes of this description the proximal end, the end closest to the operator, is at the top of the figure and the distal end, the direction away from the operator, is at the bottom of the figure.  FIG. 1A  shows the apparatus as it may be presented to the user, preloaded with fasteners and secured with actuator lock  13 , which serves as a safety to prevent the fasteners from being accidentally discharged during shipment or handling prior to their intentional use. Actuator lock  13  may be fabricated from a flexible plastic such as polypropylene by molding or die-cutting, for example, from sheet material approximately 0.030″ thick. 
         [0021]    Now with reference to  FIGS. 1A and 1B , the apparatus  10  comprises a left housing shell  20  and a right housing shell  30  which are assembled together to form a housing  25  which orients and constrains other elements of the apparatus. Extending from the proximal end of the housing  25  is an actuator  40  that may be operated by the thumb of the user. As illustrated in  FIG. 1B , removing the actuator lock  13  and pressing the actuator thumb pad  43 , causes actuator  40  to move into the housing  25 . Guiding surfaces and components described below operate within the housing  25  such that a fastener  50  is delivered through the opening in the distal end of the housing  25 . The fastener is carried on needles, and guided by guide tube support  73 , to move along a line centered between the left foot  22  and right foot  32 , over which the two sides of the tissue (see FIG. 12 a  of Danielson) have been positioned. As illustrated in FIG. 12 b  of Danielson, the two legs of fastener  50  penetrate the two sides of the cut tissue (see  68   a  and  68   b  of Danielson). After inserting the fastener  50  into the tissue, the user releases pressure on actuator thumb pad  43 , and a spring returns actuator  40  to the starting position. As the needles retract, the fastener  50  remains in the tissue as illustrated in FIG. 12 c  of Danielson. Finally as illustrated in FIG. 12 d  of Danielson, the barbs of the fastener engage, and the cut surfaces ( 68   a  and  68   b  of Danielson) return in anatomical apposition with one another. 
         [0022]    Now the various components of the apparatus  10  will be identified with reference to  FIGS. 2A and 2B .  FIG. 2A  shows the components of the present invention with the left housing shell  20  removed to illustrate the components inside.  FIG. 2B  shows the right housing shell  30  alone, so that features that are obscured by the components in  FIG. 2A , can be identified more easily. When components are symmetrical, the numbered features will be labeled with “a” for the left side and “b” for the right side, but in the text these symmetrical elements will be identified as “a,b”, even if only one component is visible in a particular drawing. 
         [0023]    Now turning to  FIG. 2A , the actuator  40  is shown in the “up” or starting position, which is maintained by actuator return spring  45 . The travel of actuator  40  is guided by actuator tongues  47   a,b,  which slide in actuator grooves  53   a,b  (see  FIG. 2B ). A resilient arm extending from the actuator  40 , forms trigger  55 , which is constrained to move in cam track  61  (see  FIG. 2B ). At the distal end of the actuator  40  needles  65   a,b  are rigidly fixed in place. The needles  65   a,b  are, in one embodiment of the apparatus  10 , made from surgical grade stainless steel and secured to actuator  40  by adhesive bonding or by being over-molded with actuator  40  by injection molding practices known in the art. 
         [0024]    Needles  65   a,b  are long and extend distally through the entire length of needle guide tubes  67   a,b.  The needle guide tubes  67   a,b  are rigidly attached to guide tube support  73 . The travel of the guide tube support  73  is guided by guide tongues  59   a,b  which slide in guide grooves  82   a,b  (see  FIG. 2B ). The upward motion of the guide tube support  73  is limited by guide stops  85   a,b  (see  FIG. 2B ), which block the travel by interfering with the proximal end of guide tongues  59   a,b.    
         [0025]    The actuator  40  is able to push and pull the guide tube support  73 , but does so indirectly by making contact with different surfaces at different times, as will be described below. A frictional engagement is provided by detent-protrusion  91  on guide tube support  73 , which contacts a detent-receiver  93  on actuator  40 . As the user continues to press on actuator thumb pad  43 , the actuator moves and contact surface  105  on the actuator comes into contact with push-pull tab  107  on the guide tube support  73 . This allows force to be transferred to needle guide tubes  67   a,b  to push the fastener into the tissue, as will be explained with reference to  FIGS. 3A-3D . Actuator  40  also has an actuator stop protrusion  120 , which extends outward from the axis of the actuator in order to contact the stop surface  225  on the top of the magazine  200 . This interference limits the distal motion of the actuator  40 , and hence the depth that the fastener is inserted into the tissue. After the fastener has been deployed, the actuator  40  is able to pull guide-tube support  73  when the proximal end of detent receiver  93  engages the push-pull tab  107 , the position illustrated in  FIG. 2A . Finally actuator  40  has lock receiver notches  127   a,b,  which allow actuator lock  13  (see  FIG. 1A ) to be inserted. When actuator lock  13  is inserted into actuator notches  127   a,b,  downward motion of actuator  40  is blocked. 
         [0026]    Continuing with reference to  FIG. 2A , a timing lever  150  is shown in the “up” or starting position, which is maintained by timing lever spring  155 . The timing lever  150  has a proximal portion which includes timing lever slot  159  which slidably contacts timing lever tab  175  on right housing shell  30  (see  FIG. 2B ) to guide and limit the travel of the timing lever  150 . Also, at the proximal end of timing lever  150 , there is a trigger engagement surface  180 , which is the proximal facing surface of a feature that protrudes from the part in order to provide momentary contact with trigger  55  on the actuator  40 . The distal portion of timing lever  150  is split into two legs  160   a  and  160   b.  The distal ends of legs  160   a,b  have retractor contours  165   a,b  respectively, which will be described in more detail with the description of the timing sequence of  FIGS. 3A-3D . 
         [0027]    Finally shown in  FIG. 2A  is a magazine cap  215 , which assembles together with magazine  200 , to form an enclosure that contains a plurality of fasteners and other components that will be described with reference to  FIG. 5 . In an exemplary embodiment, magazine  200  and cap  215  are fabricated by injection molding processes from a plastic material such as Nylon 66 (for example natural Zytel®  103  available from E. I. DuPont de Nemours &amp; Co. of Wilmington, Del.). The magazine  200  is loosely held in position within housing  25  by magazine tabs  205   a,b  (see  FIG. 4 ), which extend through magazine slots  207   a,b  (see  FIG. 2B ). 
         [0028]    The present invention will be better understood from a description of the different actions involved in deploying a fastener. The different steps are illustrated in  FIGS. 3A-3D  but the description will rely also on references to  FIGS. 2 ,  5 ,  6 A, and  6 B. In  FIG. 3A , the guide tube support  73 , the actuator  40 , and the timing lever  150  are all in their most proximal (up) position. At this, the starting point, the needles  65   a,b  are retracted such that their distal ends do not extend beyond the distal ends of the needle guide tubes  67   a,b.  This position, as illustrated in  FIG. 2A , places distal ends of needles  65   a,b  1 mm to 2 mm above the top of the front-most fastener  50   a.  When the user first pushes the actuator  40 , the frictional engagement of detent-protrusion  91  on guide tube support  73  with detent-receiver  93  on actuator  40  causes the guide tube support  73  to move downward together with the actuator  40 . 
         [0029]      FIG. 3B  illustrates the position of the same components as shown in  FIG. 3A  after the actuator  40  and guide tube support  73  have moved 1 mm to 2 mm, and the distal ends of the needle guide tubes  67   a,b  have made contact with the top of the front-most fastener  50   a.  At this point the fastener is still supported by the fastener support  270 , and cannot move downward. This interference causes the detent-protrusion  91  to disengage from the detent-receiver  93 , so that the actuator  40  can continue moving downward, while the needle guide tubes  67   a,b  temporarily remain motionless. An additional 1 mm to 2 mm of movement of actuator  40 , which occurs after the position shown in  FIG. 3B , allows the sharp distal end of each of the needles  65   a,b  to protrude from the distal end opening of the needle guide tube  67   a,b,  and begin to enter the cannulated legs of the fastener (described later with reference to  FIGS. 6A and 6B ). 
         [0030]    In  FIG. 3C , the actuator  40  has moved distally bringing trigger  55  into contact with the timing engagement surface  180  of the timing lever  150 . This movement of actuator  40  also moves needles  65   a,b,  which are mechanically fixed to the actuator  40 , to fully insert the needles into the cannulated legs of the front-most fastener  50   a  (see  FIG. 6B ). The interference between trigger  55  and timing engagement surface  180 , moves timing lever  150  downward, causing the retractor contours  165   a,b  of the timing legs  160   a,b  to move fastener support  270  rearward. As illustrated in  FIG. 3C , movement of the fastener support  270  leaves the front-most fastener  50   a  without support, held only by the frictional contact with needles  65   a,b.    
         [0031]    In  FIG. 3D , the actuator  40  has been pushed further downward, and contact surface  105  has pressed against push-pull tab  107 , causing the guide tube support  73  to push the front-most fastener  50   a  from the magazine and deliver it to the tissue (see  FIG. 12   b  of Danielson—U.S. Patent application publication number 2009/0206127 A1). At the same time, cam track  61  (see  FIG. 2B ) has caused trigger  55  to lose contact with trigger engagement surface  180  of the timing lever. As the contact is lost timing lever  150  returns to its up position, forced by timing lever spring  155 . This is the position shown in  FIG. 3D . Once the timing lever  150  has returned, fastener support  270  is urged forward by fastener support spring  287  (see  FIG. 5 ). However, the actual return of fastener support  270  to its initial forward position, is not possible until the needle guide tubes  67   a,b  move up out of the way. This happens when the user releases pressure on actuator thumb pad  43 , and return spring  45  pulls the actuator  40  upward. When actuator  40  moves upwards, the needles retract inside the needle guide tubes  67   a,b,  and the proximal surface of detent receiver  93  engages push-pull tab  107 , to pull guide tube support  73  and needle guide tubes  67   a,b  upward to the starting position shown in  FIG. 3A . 
         [0032]      FIG. 4  shows the magazine  200  removed from the apparatus and dis-assembled from cap  215 . The cap  215  may be secured to the body of the magazine by various means known in the art such as adhesive bonding or ultrasonically welding. In one embodiment illustrated in  FIG. 4 , a releasable attachment is provided by cap latches  260   a,a′,b,b′  on the magazine  200 , which have a barbed shape at the end of a flexible arm. During assembly the flexible arms bend slightly to allow the cap latches  260   a,a′,b,b′  to be inserted through openings in cap  215 . Once fully inserted, the flexible arms straighten to their original shape, and the cap latches  260   a,a′,b,b′  secure the cap by pressing against latch seats  263   a,a′,b,b′  respectively. At the top of cap  215  there is a timing lever spring tab  222  which registers the distal end of the timing lever spring  155  to hold it in place. 
         [0033]    Continuing with reference to  FIG. 4 , at the top of the magazine  200  there is a stop surface  225  which stops the distal motion of the actuator  40  by interfering with the actuator stop protrusion  120  (see  FIG. 2A ). Huggers  210   a,a′,b,b′  extend from the front of the magazine  200  where they provide a sliding contact with the needle guide tubes  67   a,b  (see  FIG. 7 ). The magazine  200  also has timing leg support surfaces  230   a,b  that provide surfaces along which the distal end of timing legs  160   a,b  (see  FIG. 6A ,  6 B) may slide. This allows timing lever  150  to be only loosely guided in its motion by timing lever tab  175  (see  FIG. 2   b ), which slides in timing lever slot  159  (see  FIG. 2A ). The critical reference geometry for timing lever  150  is provided by a sliding contact between timing legs  160   a,b  (see  FIG. 2A ) and timing leg support surfaces  230   a,b.    
         [0034]      FIG. 5  shows a cross section of the magazine  200  and cap  215  assembled together and taken along the A-A′ plane of  FIG. 4 . The left side of  FIG. 5 , referred to as the front of magazine  200 , shows the guide tube support  73  and needle guide tube  67   a  positioned against huggers  210   b  and  210   b ′. Within the magazine  200  are ten (10) fasteners  50   a  through  50   j  positioned on the fastener support  270 . The front-most fastener  50   a  is in close contact with hugger  210   b ′, and therefore positioned directly in alignment with needle guide tube  67   a.  Contact of the front-most fastener  50   a  with the huggers is assured due to contact with the remaining fasteners  50   b - j  which is urged forward by pusher  275  and pusher spring  277 . In an exemplary embodiment, pusher  275  is fabricated by injection molding processes from a plastic material such as Nylon 66 (for example Zytel® 101L available from E. I. DuPont de Nemours &amp; Co. of Wilmington, Del.) with smooth sliding surfaces facing the fastener support  270 . Pusher spring  277  is a compression spring fabricated from, for example, Type-302 stainless steel. Pusher spring  277  is held in place by pusher spring tab  283 , located on the pusher, and upper spring tab  285 , located on the cap  215 . Travel of the pusher  275  is guided by pusher tongues  280   a,b  which travel in pusher grooves  250   a,b  (see  FIG. 4 ). 
         [0035]    The exemplary embodiment of the present invention shown in  FIG. 5  includes ten (10) fasteners  50   a - j,  but it will be understood by those skilled in the art that simple changes in dimensions of the components can be made to accommodate a smaller or larger number of fasteners in the assembly. A number of fasteners in the range of 1 to 25 is contemplated by the present invention in order to provide a sufficient number to close both short and long incisions. 
         [0036]    Continuing with reference to  FIG. 5 , after one of the fasteners  50   a - j  is inserted into the tissue, the needle guide tubes move proximally to clear the way for fastener support  270  to move forward (returning to the position illustrated in in this  FIG. 5  and in  FIG. 3A ). Once needle guide tubes  67   a,b  move proximally out of the way, pusher  275  is urged forward by pusher spring  277  to advance all remaining fasteners thereby bringing the next fastener (for example,  50   b ) into the front-most position. 
         [0037]    When all fasteners have been deployed, a safety mechanism is introduced that prevents the needles  65   a,b  from being extended again. This is accomplished by pusher stop surface  286  which is the front-most portion of pusher  275 . After the last fastener is delivered and the needle guide tubes  67   a,b  move up and out of the way, pusher  275  moves forward (left in  FIG. 5 ) urged by pusher spring  277 , to position pusher stop surface  286  directly below the needle guide tubes  67   a,b.  If the user presses on the actuator  40  in this condition the guide tubes are blocked from moving downward and the needles remain with the housing  25 . 
         [0038]    Continuing with reference to  FIG. 5 , the fasteners  50   a - j  are positioned on fastener support  270  which is urged toward the front of the magazine by fastener support spring  287 . Fastener support  270  may be fabricated by injection molding processes using a material such as Food Grade Natural Acrylonitrile Butadiene Styrene (“ABS”) (e.g. Lustran 433-000000 which is available from INEOS ABS Corporation of Addyston, Ohio). Fastener support spring  287  is a compression spring fabricated from, for example, Type-302 stainless steel. It is held in place by fastener support spring tab  293 , located on the fastener support  270 , and lower spring tab  297 , located on the cap  215 . Travel of the fastener support is guided by fastener support tongues  295   a,b  which travel in fastener support grooves  240   a,b  (see  FIG. 4 ). As will be described below, the travel of the fastener support  270  reciprocates (left and right in  FIG. 5 ) over a very short distance. In an alternate embodiment, the fastener support spring  287  could be replaced by a simple resilient arm. In such an embodiment, the resilient arm, having an effective spring rate of approximately 1 lb/inch, is molded as part of one of the contacting parts, the magazine  200 , the fastener support  270  or the cap  215 , to provide the necessary restoring force to move the fastener support  270 . 
         [0039]      FIGS. 6A and 6B  show the fastener support  270  together with the front-most fastener  50   a,  guide tube support  73 , needle guide tubes  67   a,b  and the distal portion of timing legs  160   a,b,  to illustrate detailed features of these parts. The fastener  50   a  is the type of fastener described by Danielson (U.S. patent application publication number 2009/0206127 A1) and made from bioabsorbable materials. It is shown having a bridge  313  connecting two cannulated legs  317   a  and  317   b  each with barbs  333   a  and  333   b  respectively. The cannulated legs  317   a,b  have openings  325   a,b  that are chamfered at the top of legs  317   a,b.  The chamfer provides a slightly larger diameter for openings  325   a,b  to facilitate insertion of needles  65   a,b  respectively. The fastener support  270  has a ridge  340  on which the bridge  313  of the fastener rests. Below the ridge  340 , the cross-sectional shape of the fastener support  270  is designed to match features of the fasteners. In particular, sidebars  305   a,b  run the full length of the fastener support  270  and are shaped to restrain the barbs  333   a,b  of the fasteners from being easily dislodged upward. Thus the fasteners are able to slide in a linear fashion along the length of ridge  340  of the fastener support  270  arriving at the front-most position with a predictable position as illustrated. 
         [0040]    Continuing with reference to  FIG. 6A , the fastener support tongues  295   a,b  are interrupted at the rear by notches  345   a,b  which engage timing lever legs  160   a,b.  The front-most fastener  50   a  is positioned directly below the needle guide tubes  67   a,b  and aligned with the needles  65   a,b  (retracted within the tubes) because both are in slidable contact with the huggers  210   a,a′,b,b′  (see  FIG. 5 ). Timing leg  160   a  is shown with the distal end positioned in notch  345   a  of the fastener support. The rearward edge of notch  345   a  is in direct contact with retractor contour  165   a  due to the urging of fastener support spring  287  (see  FIG. 5 ). 
         [0041]    In  FIG. 6B  the same components as illustrated in  FIG. 6A  are shown in a position previously described with reference to  FIG. 3C . Downward movement “A” advances the needles  65   a,b  inserting them into the cannulated legs  317   a,b  of the front-most fastener  50   a.  Simultaneously the downward movement “B” of timing legs  160   a,b  causes retractor contours  165   a,b  to press against notches  345   a,b  to move the fastener support  270 , as illustrated by arrow “C”, away from the front-most fastener  50   a.  This action, taken immediately after the needles  65   a,b  are inserted into the fastener, leaves front-most fastener  50   a  without support from the fastener support  270 . Without support from the fastener support  270 , the front-most fastener  50   a  is supported only by frictional contact with needles  65   a,b,  and can be pushed by needle guide tubes  67   a,b  to move distally out of the magazine  200 . 
         [0042]    Needles  65   a,b  are made from surgical grade stainless steel or other similarly strong material(s) and sharpened with a conical point by means familiar to those in the art. The needle guide tubes  67   a,b  are made from stainless steel and have an external surface that is similar in shape and size to the external surface of the fastener legs  317   a,b.  Other material(s) can be used to make the needle guide tubes  67   a,b.  In a preferred embodiment, the needle guide tubes  67   a,b  and fastener legs  317   a,b  are cylindrical in shape and have the same outside diameter. The needle guide tubes  67   a,b  are spaced apart by a distance equal to the distance separating fastener legs  317   a  and  317   b  from one another. The needle guide tubes  67   a,b  are rigidly fixed to the guide tube support  73  by means known in the art. In one embodiment, the guide tube support  73  is made by injection molding using a material such as Acrylonitrile Butadiene Styrene (ABS) or acrylics (for example, Cyrolite® acrylic based compounds available from Cryo Industries, Rockaway, N.J.). The needle guide tubes  67   a,b  may be separately fabricated with a spacer-attachment structure to hold them parallel to each other. the needle guide tubes  67   a,b  with such an attachment structure may be attached to guide tube support  73  by means know in the art such as screws, thermo-staking, or adhesive bonding. The stainless steel needle guide tubes  67   a,b  may also be insert molded to be part of guide tube support  73  as a molded part. 
         [0043]      FIG. 7  shows a cross section of the components of  FIG. 4  taken along the B-B′ plane with the selected components positioned as previously illustrated in  FIGS. 3A and 6A . The front-most fastener  50   a  is shown positioned on fastener support  270  directly below the needle guide tubes  67   a,b.  The legs  317   a  and  317   b  of the front-most fastener  50   a  are in slidable contact with the huggers  210   a ′ and  210   b ′ respectively. Similarly the needle guide tubes  67   a,b  are in slidable contact with huggers  210   a,a′,b,b′.  The needles  65   a,b  are constrained to move within the needle guide tubes  67   a,b  which causes them to be axially aligned with openings  325   a,b.  By the sequence described with reference to  FIGS. 3A-3D , the needle guide tubes  67   a,b  move downward to contact the top of legs  317   a,b  and then the needles  65   a,b  advance from within the needle guide tubes to enter openings  325   a,b.    
         [0044]      FIG. 7 . illustrates the most demanding functionality of the present invention; that is, introducing the distal points of needles  65   a,b  into the openings  325   a,b  at the top of the fastener legs  317   a,b  respectively. This is accomplished without impossibly tight manufacturing processes by registering the critical parts and placing them into sliding contact with one another. This contact is created by the features on the magazine  200  called huggers  210   a,a′,b,b′.  By adapting the needle guide tubes  67   a,b  and fastener legs  317   a,b  to have the same shape (e.g. cylindrical) and to have the same cross-sectional dimensions (e.g. outside diameter), both parts can be urged into contact with a common surface. In one embodiment, illustrated in  FIG. 7 , huggers  210   a,a′,b,b′  are in sliding contact with needle guide tubes  67   a,b  and front-most fastener  50   a,  which places the needles  65   a,b  in axial alignment with the openings  325   a,b.  Because the magazine  200  is free to move within the magazine slots  207   a,b  (see  FIG. 2B ) it is able to remain referenced to the needle guide tubes  67   a,b  due to the sliding contact of the huggers  210   a,a′,b,b′.    
         [0045]    The apparatus of the present invention has been described with reference to ten (10) bioabsorbable fasteners of the type described by Danielson (U.S. patent application publication number 2009/0206127 A1). Those skilled in the art will realize that the benefits of the invention may be applied to other fasteners, whether made from bioabsorbable materials or not. Realizing that the objective is to deliver fasteners one at a time from a cartridge having a multiplicity of fasteners, it will be apparent that the apparatus may be adapted by obvious modifications to deliver fasteners in greater or lesser number than ten. Alternate embodiments also can work with fasteners having a greater or lesser number of legs than two. Fasteners that do not have cannulated legs can benefit from the present invention if such fasteners are adapted to have features such as holes or slots into which guiding elements, for example needles, may be inserted. While the present invention has been set forth in terms of a specific embodiment or embodiments, it will be understood that the present invention herein disclosed may be modified or altered to other configurations. Accordingly, the invention is not limited only to disclosed details.