Abstract:
In accordance with the present invention there is provided a surgical fastening instrument. The instrument includes a handle and a shaft extending from the handle. The shaft contains a plurality of surgical fasteners therein. The instrument also has a mechanism for first distally deploying a penetrating member from the distal end of the shaft and thereafter feeding at least one of the surgical fasteners distally from the penetrating member. The instrument further includes a lockout mechanism for preventing the penetrating member from deploying from the shaft upon feeding all of the plurality of surgical fasteners from the shaft.

Description:
This application is related to the following copending patent applications: application Ser. No. 09/692,633, Ser. No. 09/692,636; and application Ser. No. 09/692,636, which are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates, in general, to surgical fastening instrument that prevents the instrument from being fired when empty, more particularly, to a surgical fastening instrument for attaching a prosthetic over a hernia, the surgical instrument having a locking mechanism that prevents movement of an actuation trigger after the last fastener is placed. 
     BACKGROUND OF THE INVENTION 
     Surgical fastening instruments carry a number of surgical fasteners which are typically placed to ligate a vessel, hemostatically staple and cut tissue or to attach a prosthetic to tissue. All of these instruments contain a plurality of fasteners, which can be placed in a single firing, or in multiple firings. Single firing instruments, such as endocutters or various stapling instruments, contain a plurality of fasteners that are placed within tissue in a single firing. 
     In the case of endocutters or surgical staplers, the plurality of staples are contained within the stapling instrument in a replaceable stapling cartridge that holds up to six row of fine wire staples. The instrument is placed into the body, an anvil is used to clamp tissue against the replaceable cartridge, and the instrument is fired. Firing places all of the fasteners into tissue, and advances a knife to cut the tissue between the innermost rows. Once the cartridge is fired, it is desirable to lock the trigger of the endocutter to indicate to the surgeon that the instrument is empty. A U.S. Pat. No. 5,878,938 by Bittner et al. discloses a surgical stapler locking mechanism or lockout that uses a leaf spring to automatically lift a knife of the cartridge after firing, locking the instrument from firing. U.S. Pat. No. 5,673,842, also by Bittner et al. teaches a locking mechanism using an elongated member that automatically rotates from a first position to a second position as the instrument is fired. With the locking arm in the second position, the knife is free to translate upwardly and to lock the instrument. The above mechanisms incorporate an automatic lockout mechanism that depends on the movement of a knife. Of interest are surgical fastening instruments that do not contain knives. 
     Another type of locking mechanism is used with a disposable knife-less linear stapler such as that described in U.S. Pat. No. 4,527,724 by Chow et al. The instrument taught by Chow et al. is a trigger safety that prevents closure of the trigger. The trigger safety is hingedly attached to a handgrip of the surgical instrument and is foldable to a locking position to contact and prevent movement of the actuation trigger. This locking mechanism differs from the previously described automatic locking mechanisms in that it requires manual engagement and disengagement of the locking mechanism. 
     The above mechanism indeed locks the trigger of a single firing surgical instrument that has no knife, and requires manual engagement of the lockout. However, the above instruments are not multifire instruments. Multifire instruments contain a plurality of fasteners that are held within the surgical instrument, and the fasteners can be applied one at a time. These instruments are capable of multiple firings or applications of fasteners to tissue. These types of instruments can be fired repeatedly until the instrument runs out of fasteners or the surgery is complete. 
     One well known multi-firing instrument is a clip applier such as the ER320 LIGACLIP™ Multiple Clip Applier manufactured and sold by Ethicon EndoEND-Surgery, Cincinnati, Ohio. Clip appliers are used to close or ligate vessels during surgery, and are commonly used to ligate the cystic duct and cystic artery during the removal of a gall bladder. These surgical instruments can contain up to twenty clips and contain a yellow feed shoe that pushes or feeds the clips distally within the instrument. A lockout is operatively attached to the yellow feed shoe, and falls into an opening within the feed bar to lock the feed bar of the instrument when the last clip is fed. The locked feed bar prevents the feed mechanism, the trigger, and the clip forming mechanism from moving. A locking mechanism of this type is described in U.S. Pat. No. 5,171,249 by Stefanchik et al. Whereas this locking mechanism is automatic, and the instrument contains no knife, it depends on linear motion of elements of the mechanism to lock the trigger of the surgical instrument. 
     Of special interest are surgical fastening instruments that are used to attach prosthetics such as a hernia mesh to tissue. One type of these devices employs a lockout. The surgical instrument is a multi-firing coil fastening applier that uses helical wire fasteners. The helical wire fasteners are stored serially within the shaft, and are corkscrewed or rotated into tissue. A variation of this surgical instrument is a coil fastening applier and remover. The coil fastening applier and remover is unique in the realm of hernia mesh attachment instruments, as it is able to remove fasteners from tissue. A user activated lockout mechanism is provided that locks an internal drive rod. Next, the instrument is placed over and engaged with a coil fastener positioned within tissue. The coil fastener applier is rotated to withdraw the coil fastener from tissue. Unlocking the lockout reactivates the coil fastener applying mechanism. A locking mechanism of this type is found in PCT application No. WO 98/11814 by Holstein et al. Although there is a lockout upon this hernial fastening instrument, it is not automatically activated when the last fastener is fired. Rather, the lockout is used to disengage and engage the coil fastener applying mechanism and does not lock all of the functions of the instrument. 
     Yet another locking mechanism for a multi-firing fastening instrument is described in European Patent Specification EP 0 392 750 by Green et al. The locking mechanism is for a fascia stapler, and has a lockout to prevent firing of the stapler when it is empty. A ring shaped counter wheel is provided having a plurality of equal spaced tabs extending radially inwardly, and one cross bar across one pair of the tabs to create a closed hoop. The number of tabs corresponds to the number of staples within the stapler. A longitudinally translating lever having an angled forward end reciprocates within the instrument. The angled lever, when reciprocated distally, contacts the tabs and snaps upwardly to rotate the counter wheel. A trigger also moves distally with the angled lever and normally slips between two tabs of the counter wheel. When the last staple is fired, the cross bar of the hoop engages with the trigger pushing it proximally to release a bolt, which snaps through the trigger and locks the handle of the stapler. Whereas the above stapling instrument utilizes a rotary lockout mechanism, the lockout mechanism is both complicated and expensive. Additionally, it also uses a secondary mechanism to rotate the counter wheel, which adds further cost and complexity to the mechanism. 
     What is needed is an improved lockout mechanism for a surgical instrument that can attach a prosthetic to tissue. Such a mechanism would provide superior advantages such as lower cost, reduced complexity, and automatic operation. Presently, there are no known rotary lockout mechanisms for a surgical fastening instrument that can meet all of the needs outlined above 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention there is provided a surgical fastening instrument. The instrument includes a handle and a shaft extending from the handle. The shaft contains a plurality of surgical fasteners therein. The instrument also has a mechanism for first distally deploying a penetrating member from the distal end of the shaft and thereafter feeding at least one of the surgical fasteners distally from the penetrating member. The instrument further includes a lockout mechanism for preventing the penetrating member from deploying from the shaft upon feeding all of the plurality of surgical fasteners from the shaft. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is an isometric view of a surgical instrument wherein a left handle half is removed to show the elements within and a trigger is in an open position; 
     FIG. 2 is an isometric view of the surgical instrument of FIG. 1 wherein the trigger is moved from the open position of FIG. 1 to a closed position as shown, and an end effector is extended from the surgical instrument; 
     FIG. 2B is an exploded isometric view of some of the internal elements of the surgical instrument of FIG. 1, with some elements removed for clarity; 
     FIG. 3 is a side view, in cross section, of a first side of the surgical instrument of FIG. 1 with the left handle half removed, wherein all of the internal elements are shown assembled and the trigger is in an open position; 
     FIG. 4 is a side view of a second side of the surgical instrument of FIG. 3 with the left handle half in place and with the right handle half removed, showing all of the internal elements therein and the trigger in an open position; 
     FIG. 5 is a side view of the first side of the surgical instrument of FIG. 3 wherein the trigger is moved to a partially closed position to extend the end effector from the surgical instrument; 
     FIG. 6 is a side view of the second side of the surgical instrument of FIG. 5, wherein the trigger is moved to a partially closed position to extend the end effector from the surgical instrument; 
     FIG. 7 is a side view of the first side of the surgical instrument of FIG. 5 wherein the trigger is moved to a fully closed position to retract a first portion of the end effector into the surgical instrument, and to expose a portion of a fastener at the end effector; 
     FIG. 8 is the view of the second side of the surgical instrument of FIG. 7, wherein the trigger is moved to a fully closed position to retract an upper portion of the end effector into the surgical instrument, and to expose a portion of a fastener at the end effector; 
     FIG. 9 is an isometric view of a fastener of the preferred invention wherein the fastener of the preferred invention has a pair of distal barbs and a pair of longer proximal arms, the fastener of the preferred invention is shown in an unconstrained state; 
     FIG. 10 is a side-view of FIG. 9 wherein the fastener of the preferred invention is shown in an unconstrained state; 
     FIG. 11 is an isometric view of the fastener of FIG. 9 wherein the fastener of the preferred invention is shown in a constrained state as found within the surgical instrument of FIG. 1; 
     FIG. 12 is a side-view of FIG. 11 wherein the fastener of the preferred invention is shown in a constrained state; 
     FIG. 13 is a bottom-view of FIG. 12 wherein the fastener of the preferred invention is shown in a constrained state; 
     FIG. 14 is a cross-sectional side view of a distal end of a shaft of the surgical instrument of the present invention showing the end effector normally retracted therein and a plurality of surgical fasteners of the preferred invention contained therein; 
     FIG. 15 is a cross-sectional view  10 — 10  of the shaft and the end effector of FIG.  9  and showing a passageway and a fastener of the preferred invention contained therein; 
     FIG. 16 is a fragmentary perspective view of a surgical grasper instrument placing a mesh patch over a defect or hernia in the inguinal floor of the lower abdomen, particularly the left inguinal anatomy; 
     FIG. 17 is a cross-sectional side view of the inguinal floor of the lower abdomen of FIG. 16 illustrating the placement of the mesh patch above the tissue in preparation for repair of the defect, according to the present invention; 
     FIG. 18 is a cross-sectional side view of the inguinal floor of the lower abdomen wherein the distal end of the shaft of FIG. 14 is pushing the mesh patch downward onto the inguinal floor, and the end effector is moving downwardly within the shaft with a fastener contained therein; 
     FIG. 19 is a cross-sectional side view of the inguinal floor and instrument of FIG. 18 wherein the end effector of the present invention is extended from the shaft and into the inguinal floor, the end effector containing a fastener of the preferred invention therein; 
     FIG. 20 is a cross-sectional side view of the inguinal floor and instrument of FIG. 19 wherein a first portion of the end effector is partially retracted into the shaft to deploy a first barb of the fastener of the preferred invention contained therein and to engage the first barb with the inguinal floor; 
     FIG. 21 is the cross-sectional side view of FIG. 20 wherein the first portion of the end effector of the present invention is fully retracted into the shaft, the full retraction releasing the arms of the fastener of the preferred invention into the portion of the shaft previously occupied by the first portion of the end effector; 
     FIG. 22 is the cross-sectional side view of FIG. 21 wherein a second portion of the end effector of the present invention is fully retracted into the shaft, the full retraction engaging a second barb of the fastener of the preferred invention with the inguinal floor and both arms with the shaft; 
     FIG. 23 is a cross sectional side view of FIG. 22 wherein the shaft of the surgical instrument of FIG. 22 has moved upwardly to release the arms of the fastener of the preferred invention, the released arms attaching the surgical mesh to the inguinal floor; 
     FIG. 24 is a is a fragmentary side-view of a trigger lockout mechanism of the present invention of FIG. 1 with a lockout arm fixably attached to the pivotable trigger, and operably coupled with a lockout wheel; 
     FIG. 25 is a fragmentary cross-section view of the lockout mechanism of the present invention showing the lockout wheel in an initial position and engaged with a wheel detent, wherein the lockout arm is moving upwardly from a start position (dashed lines) to a second position (cross section) adjacent to the lockout wheel; 
     FIG. 26 is a fragmentary cross-section view of FIG. 25 showing the upwardly moving lockout arm engaging with a first tooth of the lockout wheel, wherein the engagement has rotated the locking wheel one tooth counterclockwise and the locking arm is preparing to return to the initial position (dashed lines); 
     FIG. 27 is a fragmentary cross-section view of FIG. 26 showing the upwardly moving lockout arm engaging with a final tooth of the lockout wheel, wherein the repeated firing of the trigger has rotated the lockout wheel to the final tooth, and a locking tab is positioned just below the upwardly moving locking arm (cross section); 
     FIG. 28 is a fragmentary cross-section view of FIG. 27 showing the upwardly moving lockout arm further engaging with a final tooth of the lockout wheel, wherein the lockout wheel has rotated counterclockwise to position the locking tab below the lockout arm; 
     FIG. 29 is a fragmentary cross-section view of FIG. 28 showing the detent arm preventing further rotation of the locking wheel and the lockout arm attached to the trigger captured between a tooth and the locking arm of the locking wheel. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention pertains, in general, to surgical fastening instrument that prevents the instrument from being fired when empty. More particularly, to a surgical fastening instrument for attaching a prosthetic over a hernia, the surgical instrument having a locking mechanism that prevents movement of an actuation trigger after the last fastener is placed. 
     By way of example, the present invention is illustrated and described in conjunction with a repair of an inguinal hernia. However, it should be understood that the present invention is applicable to various other surgical procedures that require the repair of defects in tissue. 
     The Surgical Instrument 
     As best shown in FIGS. 1 and 2, the surgical instrument of the present invention is a hand held surgical instrument  35  containing a plurality of surgical fasteners or surgical elements that are generally used for the attachment of a prosthetic to tissue, or as a tissue marker. The surgical fasteners  105  of the present invention are formed from a superelastic nickel titanium alloy, are stored within the surgical instrument in a compressed or collapsed state, and expand to an unconstrained state upon release from the surgical instrument. Actuation of the instrument simultaneously releases a fastener  105  of the present invention from a distal end of the instrument and indexes the plurality of fasteners  105  within the instrument. 
     Surgical instrument  35  of the present invention has a handle  40 , an elongated shaft  92  extending distally from the handle  40 , and a trigger  85  extending downwardly from the handle  40 . Handle  40  has a right half  41  and a left half  42  that are generally mirror images of each other and, in FIGS. 1 and 2, the left half  42  is omitted. Elongated shaft  92  is fixedly attached to the handle  40 , and is formed from a rigid hollow material such as stainless steel tubing. A grip  43  is fixedly attached to and extends downwardly from a proximal end of handle  40  and adjacent to the trigger  85 . Trigger  85  pivotably mounts within handle  40  and is moveable from an open position as shown in FIG. 1 to a closed position adjacent to the grip  43  as shown in FIG.  2 . Movement of the trigger  85  to the closed position extends an end effector  95  from a distal end of the shaft  92  (FIG. 2) for the placement and release of a fastener. 
     FIG. 2B is an isometric exploded view of the majority of the elements found within the surgical instrument  35 . The exploded view is provided to familiarize the reader with the key elements contained therein, and the method of assembly used to form the surgical instrument  35 . For clarity, a number of elements such as the left handle half  42  are removed. Some of the elements of FIG. 2B are complex in shape and the reader is advised to return to this figure for identification or comprehension of features referenced below. The elements of the surgical instrument  35  are contained within the right and left handle halves  41 ,  42  which can be formed from an engineering thermoplastic such as styrene, polycarbonate, or any one of a number of suitable materials. A shaft slot  44  is located at the distal end of the upper portion of the handle halves  41 ,  42  for the reception and retention of the shaft  92  therein. 
     A latch slot  45  is located proximally to and below the shaft slot  44  within the right handle half  41 . Latch slot  45  is right-angled in shape and is provided for the reception of a latch  55  therein. Latch  55  has a rigid latch post  57  at a distal end and a right-angled beam  56  extending distally therefrom. Beam  56  is formed from a resilient spring material such as stainless steel. A distal end of beam  56  is captured and held within the latch slot  45  with a significant amount of the beam  56  cantilevering therefrom. The cantilever portion of the beam  56  enables the latch post  57  to move freely up and down as the beam  56  deflects. The significance of the latch  55  will be described later. 
     A first and a second slider  60 ,  70  extend generally proximally and distally throughout the shaft  92  and handle  40  of the surgical instrument  35  and are slidably retained within a pair of guide slots  46  located within each of the handle halves  41 , 42 . In FIG. 2B, the first and second sliders  60 ,  70  are shown spaced apart prior to assembly to show a plurality of fasteners  105  that are stored therebetween. Fasteners  105  extend along the entire length of the first and second sliders  60 ,  70 . First and second sliders  60 ,  70  have distal first and second feed members  61 ,  71  that slidably mount within the shaft  92 , and a larger proximal first and second sequencing member  62 ,  72  that slidably mount within the handle halves  41 ,  42 . First and second feed members  61 ,  71  are semi-circular in cross section and have a first and second outer surface  64 ,  74 . A pair of first and second stab posts  64   a,    74   a  extends outwardly from a distal end of each first and second outer surface  64 ,  74  respectively. A first and second contact surface  63 ,  73  completes the semi-circular cross section of the first and second feed members  61 ,  71  respectively. First and second contact surfaces  63 ,  73  opposably face each other along the entire length of the first and second sliders  60 ,  70  and have a first and second fastener channel  65 ,  75  extending therein. When assembled, first and second sliders  60 ,  70  make sliding contact along the entire length of first and second contact surfaces  63 ,  73  and first and second fastener channels  65 ,  75  form a hollow rectangular channel for the holding and feeding of fasteners  105  serially therethrough (FIG.  15 ). 
     The fastener channels  65 ,  75  of the first and second sliders  60 ,  70  are “U” shaped and have a pair of opposed surfaces or channel floors therein. The surfaces have a plurality of fastener drive features located therein. As best shown in the enlarged FIG. 14, these fastener drive features or sawteeth  120 , extend proximally to distally along the entire length of the floors of the first and second fastener channels  65 ,  75  and are equally spaced a longitudinal distance “D” apart. The distance “D” is between 2 inches and 0.005 inches. Each sawtooth  120  has a proximal incline  122  and a distal step  121  as shown. The role of the sawteeth  120  in the feeding of the fasteners  105  will be discussed in detail later. 
     At the distal end of the first and second fastener channels  65 ,  75  are a first and a second fastener guide  66 ,  76  respectively which are a tapered lead-in at the proximal end of fastener channels  65 ,  75  to assist in the loading of the fasteners  105  therein. These fastener guides  66 ,  76  are generally mirror images of each other. In FIG. 2B, the first fastener guide  66  is hidden. 
     The larger proximal portions of the first and second sliders  60 , 70  are the first and second sequencing members  62 ,  72 , which control the timing and sequencing of a fastener feeding mechanism that releases a fastener from the distal end of the instrument, and indexes or feeds the plurality of fasteners distally within the instrument. The first sequencing member  62  has a pair of guide ribs  68  extending laterally outwardly from either side and a first spring stop  67  extending upwardly at a proximal end. Guide ribs  68  mount within the guide slots  46  of the right and left handle halves  41 ,  42  and slidably secure the assembled sliders  60 ,  70  within the handle  40 . A pair of “C” shaped guide channels  69  are located underneath and extend longitudinally along the proximal half of the first sequencing member  62 . The second sequencing member  72  has second spring stop  77  located at a proximal end of second sequencing member  72  and a forked stop  78  extending upwardly at a distal end. A cam plate  79  extends outwardly from the far side of the second sequencing member  72  towards the right handle half  41 . A pair of slider ribs  83  extends laterally outward along the proximal half of the second sequencing member  72 . First and second sliders  60 ,  70  can be formed as a single piece from an engineering thermoplastic such as a liquid crystal polymer, a polycarbonate, nylon, a styrene or the like. 
     The first and second sliders are slidably interlocked together by inserting the pair of slider ribs  83  located on the second sequencing member  72  into the pair of guide channels  69  of the first sequencing member  62 . First and second stab plates  96 ,  97  are then attached to the first and second sliders  60 ,  70  by placing first and second stab plates  96 ,  97  over first and second stab posts  64 a,  74 a and then placing the assembled stab plates  96 ,  97  and first and second sliders  60 ,  70  into the hollow shaft  92  to form a shaft sub-assembly. This method of stab plate retention is best shown in FIG.  14 . The assembly of the stab plates  96 ,  97  and the first and second sliders  60 , 70  form a piercing member for piercing tissue during the placement of a fastener  105 . Stab plates  96 ,  97  can be made from a rigid material such as stainless steel. 
     Next, the shaft sub-assembly is placed into an fastener feeding station (not shown) and the fastener  105  are fed one at a time into the first and second fastener guides  66 , 76  and into the hollow channel formed from fastener channels  65 , 75 . The fastener  105  is inserted until the fastener  105  engages with the feeding mechanism, which will be described later. Once the fastener  105  is in place, the first and second sliders  60 , 70  are reciprocated proximally and distally relative to one another to feed or index the fastener  105  further into the shaft sub-assembly. This process is repeated for each new fastener  105  until the first and second sliders  60 ,  70  are fully loaded with a plurality of fasteners  105  in a serial fashion. The plurality of fasteners  105  are equally spaced along the entire length of the first and second sliders  50 ,  60 . The shaft sub-assembly containing the fastener  105  is then placed into the right handle half  41 . Shaft  92  is received in shaft slot  44  and the guide ribs  68  of the first slider  60  are slidably placed into the guide slot  46 . Next, a lockout wheel  100  is placed into a wheel receptacle  48  located within the right handle half  41  at a position proximal to the pivot bore  47 . Lockout wheel  100  is a disk having a plurality of ratchet teeth  101  extending outwardly from a rim of the wheel  100 . A trigger assembly is constructed by placing a trigger plate  87  and a lockout arm  88  over a pivot  86  that extends laterally on either side of trigger  85  and fixably attaching them to trigger  85  with a pair of pins  89 . A drive arm  90  extends upwardly from the trigger plate  87  and a spring post  91  extends from the far side of the trigger plate  87  towards the right handle half  41 . An end of a trigger spring  104  (FIG. 3) is then placed over spring post  91 . The trigger assembly is then placed into the right handle half  41  by placing the far side pivot  86  (not shown) into a pivot bore  47 . Trigger  85 , trigger plate  87 , and lockout arm  88  are shown as separate pieces but can alternately be constructed as a single piece from an engineering thermoplastic such as polycarbonate, styrene or the like. 
     FIG. 3 shows the fully assembled elements of the handle  40 . Prior to the view shown in FIG. 3, the free end of the trigger spring  104  has been stretched and attached to a spring pin  49  of the grip  43 . The attachment of the free end of the trigger spring  104  tensions trigger spring  104 , and biases the trigger  85  to the open position shown. Next, a first return spring  115  was compressed and placed into a first spring pocket formed between the first spring stop  67  of the first slider  60  and a first spring rib  50  of the handle halves  41 , 42 . A second return spring  116  was also compressed and placed into a second spring pocket formed between the second spring stop  77  of the second slider  70  and a second spring rib  51 . Finally, the left handle half  42  was attached to the right handle half  41  to complete the assembly of the surgical instrument  35 . The left handle half  42  has been removed for clarity. 
     The Sequencing Mechanism 
     The instrument of FIGS. 3-8 shows the operation of the sequencing mechanism that controls the timing and movement of elements within the surgical instrument  35 . The sequencing mechanism is actuated by the trigger  85  and moves the first and second sliders  60 ,  70  distally from a first proximal position to a second distal position, returns the first slider  60  to the proximal position, then returns the second slider  70  to the proximal position. This sequence of motion places a fastener into tissue and advances the plurality of fasteners  105  distally. The sequencing mechanism consists of the latch  55 ; the trigger assembly described above, the first and second return springs  115 ,  116 , and the first and second sequencing members  62 ,  72  of the first and second slider  60 ,  70 . 
     FIG. 3 shows a first or left side view of the surgical instrument of FIG. 1 with the right handle half  41  in place, the left handle half  42  removed for clarity, and the trigger  85  in the initial open position. The first and second sliders and second return springs  115 ,  116  are biasing the first and second sliders  60 ,  70  distally within the handles  41 , 42 . The trigger  85  of the trigger assembly is in the full open position with the drive arm  90  poised to operatively engage a proximal end of the guide rib  68  of the first sequencing member  62 . First and second sliders  60 , 70  are in the first proximal position. 
     FIG. 4 shows the second or right side view of the surgical instrument of FIG. 3 with the left handle half  42  in place and with the right handle half  41  removed. The latch  55  is visible in this view, and the latch post  57  of latch  55  is operatively engaged with a first ramp  69   a  located on the distal end of the first sequencing member  62 . A portion of the first and second spring ribs  50 , 51  and the latch slot  45  of the right handle half  41  are shown in cross-section for clarity. 
     FIGS. 5 and 6 show the left and right side views of the assembled surgical instrument  35  respectively, and show the first and second sliders  60 ,  70  translated or moved distally from the first position of FIGS. 3-4 to the second position by the trigger  85 . The distal movement of first and second sliders  60 ,  70  has extended the end effector  95  from the distal end of the shaft  92 . The trigger  85  is in a first partially closed position and is poised to release the first slider  60  from the drive arm  90  of the trigger assembly. 
     In FIG. 5, as trigger  85  rotates counter-clockwise towards the grip  43 , the drive arm  90  rotates into operative engagement with the guide rib  68  and moves the first slider  60  distally. As first slider  60  moves distally, the forked stops  78  of the second slider  70  are contacted, pushing the second slider  70  distally. The distally moving first and second sliders  60 ,  70  compress the first and second return springs  115 ,  116  as shown. The lockout arm  88  of the trigger assembly is moving upwardly, and is rotating the lockout wheel  100 . 
     In FIG. 6, as the first and second sliders  60 ,  70  move distally, they deflect the latch post  57  of the latch  55  downwardly to slide along the first ramp  69   a  of the first slider  60  and a second ramp  80  of the second slider  70 . Latch post  57  of the latch  55  passes the second ramp  80  and deflects upwardly to lock against a third ramp  81  of the second slider  70  and against a bottom surface  62   a  of the first sequencing member  62 . With the latch  55  in this position, the second slider  70  is locked in the distal position and cannot move proximally. 
     FIGS. 7 and 8 show the left and right side views of the assembled surgical instrument  35  respectively, after the first slider  60  has reciprocated or returned back to the first proximal position of FIGS. 3 and 4 to partially release a fastener  105  from the end effector  95 . 
     As shown in FIG. 7, after the guide rib  68  is released from the drive arm  90 , the first slider  60  reciprocates distally to the first proximal position from the second distal position shown in FIGS. 5 and 6. Slider  60  was returned to the proximal position by first return spring  115 . The proximal movement of the first slider  60  retracted the first stab plate  96  proximally into the shaft  92  and released a distal end of the fastener  105  as shown. The lockout arm  88  moved upwardly from and disengaged with the lockout wheel  100 . 
     In FIG. 8, as first sequencing member  62  moves proximally, the bottom surface  62   a  of the first sequencing member  62  moves distally away from the latch post  57  enabling the latch  55  to deflect upwardly to the un-deflected position shown in FIG.  3 . This movement unlocks the second sequencing member  72 . With the second sequencing member  72  unlocked, the compressed second return spring  116  will reciprocate the second slider  70  back to the original proximal position of FIG.  3 . As the second slider  70  reciprocates back to the first proximal position, latch post  57  is deflected upwardly by the third ramp  81  of the cam plate  79  to travels over a top surface  82  of the distally moving cam plate  79  and returns to the position of FIG.  3 . At this point, if an instrument lockout is not actuated, the trigger  85  is released to bring the elements of the instrument back to the positions shown in FIG.  3 . 
     The Fastener 
     FIGS. 9-13 are expanded views showing the novel surgical anchor or fastener  105  of the present invention. A plurality of fasteners  105  of the present invention are contained serially within the surgical instrument  35  (FIG. 2B) and are used to fasten or suture a prosthetic such as a surgical mesh pad onto tissue. The fastener  105  of the present invention is elastic and is shown in its original unconstrained state in FIGS. 9 and 10. When fastener  105  is distorted or constrained, it will return to its original shape when released. Fastener  105  can be formed from a sheet or foil of a pseudoelastic or superelastic shape memory alloy to take advantage of pseudoelastic or superelastic properties thereof, or an elastic or spring grade of steel, stainless steel, copper, or other titanium alloys. 
     Most preferably, fastener  105  is made from an alloy comprising from about 50.5% (as used herein these percentages refer to atomic percentages) Ni to about 60% Ni, and most preferably about 55% Ni, with the remainder of the alloy Ti. Preferably, the fastener is such that it is superelastic at body temperature, and preferably has an Af in the range from about 24° C. to about 37° C. The superelastic design of the fastener  105  makes it crush recoverable which makes it possible to store a large fastener  105  within a small diameter shaft  92 . 
     As mentioned above, it is preferred that the fastener  105  of the present invention be made from a superelastic alloy and most preferably made of an alloy material having greater than 50.5 atomic % Nickel and the balance titanium. Greater than 50.5 atomic % Nickel allows for an alloy in which the temperature at which the martensite phase transforms completely to the austenite phase (the Af temperature is below human body temperature and preferably is about 24° C. to about 37° C. so that austenite is the only stable phase at body temperature. 
     The unconstrained fastener  105  of FIGS. 9 and 10 has a distal tip  106  with a first and a second barb  107 ,  108  and a body  109  extending proximally therefrom. The distal tip  106  of the fastener  105  of the present invention is rounded, as the fastener  105  does not need to penetrate tissue. Alternately, the distal tip  106  of the fastener  105  can be made sharp or pointed if desired. First and second barbs  107 ,  108  extend proximally from the distal tip  106  and away from the body  109 . The first and second barbs  107 ,  108  can be curved. The distal end of the body  109  bifurcates into a first and a second leg  110 ,  111  that extend distally from the body  109  and away from each other. First and second legs  110 ,  111  of the present invention can be curved, and can form the everted configuration of FIGS. 9 and 10. 
     FIGS. 11-13 shows an isometric view, a side view, and a bottom view of the fastener  105  of the present invention wherein the fastener  105  is shown in a constrained state that the fastener  105  assumes when stored within the surgical instrument  35  (FIG.  1 ). The fastener  105  will revert to the unconstrained shape of FIGS. 9 and 10 when released from the surgical instrument  35 . 
     The Feeding Mechanism 
     FIGS. 14 and 15 are enlarged partial cross-sectional views of the distal end of the shaft  92  of FIG. 3 showing the first and second sliders  60 , 70  at the first or un-actuated position wherein they are recessed into the shaft  92 , and the fasteners  105  contained therebetween. At the first distal position, the trigger  85  of the surgical instrument  35  is fully open (FIG. 3) and the sawteeth  120  of the first slider  60  are lined up with and directly opposed from the sawteeth  120  within the second slider  70 . FIG. 15 shows how the first and second fastener channels  65 ,  75  form a passageway for the reception of the fasteners  105  therein. 
     The feeding mechanism is novel as it uses the fasteners  105  themselves as a part of the feeding mechanism. As shown in FIG. 14, the feeding mechanism  59  has three distinct elements: the first slider  60 , the second slider  70 , and the plurality of fasteners  105  stored in a serial fashion therebetween. Fasteners  105  are held between the sawteeth  120  with the barbs  107 ,  108  deflecting outwardly to center the fasteners  105  between the sawteeth  120 . First and second legs  110 ,  111  of the fasteners  105  are biased outwardly, contacting the surfaces of the sawteeth  120 . The distal ends of the first and second legs  110 ,  111  are positioned within the pockets at the junction of the step  121  and the incline  122 , and are operatively engaged with the steps  121  and slidingly engaged with the inclines  122 . It is the positive contact or engagement of the fasteners  105  with the steps  121  and sliding contact or engagement with the inclines  122  that propels or feeds the plurality of fasteners  105  between the reciprocating first and second sliders  60 ,  70  and places the fastener  105  into tissue. 
     To someone skilled in the art, it can be seen that given the elements of the feeding mechanism  59  described above, distal movement of both of the first and second sliders  60 ,  70  results in operative engagement of the fasteners  105  with the steps  121  of both sliders  60 ,  70 . This operative engagement with the distally moving sliders  60 ,  60  will result in distal movement of the fasteners  105 . If one of the sliders such as first slider  60  is moved distally while the other remains stationary, the fasteners  105  operably couple with and move with the moving slider  60 , while slidingly engaging with the stationary slider  70 . And, if one of the sliders such as first slider  60  moves proximally while the other remains stationary, the fasteners  105  operatively engage with the stationary slider  70  and remain stationary and slidably engaged with the moving slider  60 . 
     With the above combinations of motions and reactions, there are three different sequences of motion possible with the sliders  60 ,  70  that will feed the fasteners  105  distally through the surgical instrument  35  (FIG.  3 ). One of these sequences of motion was selected for use with the surgical instrument  35  of the present invention, as it is best suited to place a fastener  105  into tissue. This feeding sequence using the feeding mechanism  59  of the present invention is shown in a step by step manner beginning with the start position shown in FIG. 14, and finishing in FIGS. 18-22. The other two feeding sequences will be described later. 
     The sequencing mechanism of the present invention first moves the first and second sliders  60 ,  70  distally (FIGS.  18 , 19 ) from a first proximal position (FIG. 14) to a second distal position (FIG.  19 ). This movement positively engages the fasteners  105  with the first and second sliders  60 ,  70  and moves the fasteners  105  distally from the first position to the second position. Moving both the first and second sliders  60 ,  70  (FIG. 14) from a first proximal position to a second distal position moves the entire plurality of fasteners  105  distally within the surgical instrument  35 . That is, each fastener  105  (with the exception of the distalmost fastener  105 ) now occupies the position of the preceding fastener  105 . 
     Next, as shown in FIGS. 20,  21 , the first slider  60  is moved or reciprocated proximally from the second distal position back to the first proximal position to opposedly align the sawteeth  120  of the first and second sliders  60 ,  70 . As shown, the fasteners  105  are operatively engaged with the stationary second slider  70  and remain stationary (longitudinally) within the shaft  92 . 
     Finally, as shown in FIG. 22 the second slider  70  is moved or reciprocated proximally from the second distal position back to the first proximal position, and to realign the sawteeth  120  within the first and second sliders  60 ,  70 . The fasteners  105  in operative contact with the stationary first slider  60  remain stationary and in sliding contact with the distally moving second slider  70 . As shown in FIG. 22, the first and second sliders  60 ,  70  have placed the distalmost fastener  105  within tissue and have moved distally back to the first position. A new fastener  105  is shown within first and second sliders  60 ,  70 , ready for placement within tissue. 
     As described above, there are two additional embodiments of the present invention wherein different sequences of motion are possible with the first and second sliders  60 ,  70 . These alternate sequences of motion will also feed the fasteners  105  distally through the surgical instrument  35  (FIG.  3 ). 
     In the next or second embodiment, the sequence of motion is to fix one of the first or sliders such as first slider  60  and to reciprocate the remaining slider  70  distally from the first position to the second position and back to the first position. In the third embodiment, the sequence of motion is altered wherein the first and second sliders  60 ,  70  are reciprocated in opposite directions at the same time. 
     The Anatomy 
     Referring now to FIG. 16, one typical application of the surgical instrument of the present invention is a repair of a defect, such as an inguinal hernia  125 , located in inguinal tissue such as the inguinal floor  126 . The anatomical structures of the left inguinal anatomy of a human patient are illustrated in order to point out the usefulness of the present invention. 
     Generally, the inguinal hernia  125  is accessible through iliacus muscle  127 . As can be well appreciated, a network of vessels and nerves exist in the area of a typical inguinal hernia  125 , which requires a surgeon to conduct a hernia repair with great skill and caution. For instance, in the transverse abdominis aponeurosis  128 , an internal ring  129  permits gastric vessels  130  and Vas deferens  131  to extend therethrough over an edge of inguinal ligament  132 . Femoral canal  133  is located near Cooper&#39;s ligament  134  and contains external iliac vessels  135  and inferior epigastric vessels  136 . 
     In many cases, the edge of the inguinal ligament  132  and Cooper&#39;s ligament  134  serve as anatomical landmarks and support structures for supporting surgical fasteners such as those mentioned previously. The area containing the external iliac vessels  135  and the Vas deferens  131  is commonly known as “the Triangle of Doom” to surgeons. Accordingly, the surgeon should avoid injuring any of these vessels described above and care must be taken when performing dissection, suturing or fastening within this area. 
     In FIGS. 16 and 17, a prosthetic or a mesh patch  140  is placed over the inguinal hernia  125  with a surgical grasping instrument  145  as the first step in the repair of the inguinal hernia  125 . The mesh patch  140  may consist of any desired configuration, structure or material. However, the mesh patch  140  is preferably made of PROLENE™ (a known polymer made up of fibers) and preferably configured as mesh. It is within the training and comfort zone for surgeons to use the PROLENE™ mesh patch  140  since the mesh patch  140  is easily sized, such as providing a side slot  141 , for accommodating the gastric vessels  130  and the Vas deferens  131 . 
     As illustrated, the mesh patch  140  is placeable over the inguinal hernia  125  for providing a sufficient barrier to internal viscera (not shown) of the abdomen which would otherwise have a tendency to protrude through the inguinal hernia  125  and cause the patient a great deal of pain and discomfort. FIG. 11 shows a side view of the mesh patch  140  being placed onto the inguinal floor  126 . The mesh patch  140  is now attachable to the inguinal floor  126 . 
     The Method 
     FIGS. 18-23 are also used to illustrate the method of use of the surgical instrument  35 . These cross-sectional side views of the distal end of the shaft  92  show the steps involved in using the surgical instrument  35  as it places a novel fastener  105  of the present invention into the inguinal floor  126  to attach the mesh patch  140  thereto. 
     FIG. 18 is a cross-sectional side view of the inguinal floor  126  of the lower abdomen wherein the surgeon has placed the distal end of the shaft  92  into the area near the patient&#39;s inguinal hernia  125 . The surgeon has selected an attachment point or surgical site and is using the distal end of the surgical instrument  35  to push the mesh patch  140  downward onto the inguinal floor  126 . The distal end of the shaft  92  is deliberately positioned over an opening  142  within the mesh patch  140  for the placement of a fastener  105  therethrough. The position of the end effector  95  within the cross-sectioned shaft  92  indicates that the trigger  85  has been partially activated by the surgeon. The partial movement or activation of the trigger  85  is translating or moving the first and second sliders  60 , 70  distally (downwardly in FIG. 14) from the initial position shown in FIG.  14 . 
     As illustrated in FIG. 19, the surgeon has continued to actuate or move the trigger  85 , has moved the trigger  85  to the first position (FIGS. 2,  5 , and  6 ), and has fully extended or translated the first and second sliders  60 , 70  of the end effector  95  from the shaft  92 . The extended end effector  95  has penetrated through the opening  142  within the mesh patch  140  and into the inguinal floor  126 . Although shielded from tissue contact by the end effector  95 , the first and second barbs  107 , 108  of the distalmost fastener  105  are placed within tissue of the inguinal floor  126 . 
     Continued actuation of the trigger  85  by the surgeon moves the trigger  85  from the from the first partially closed position shown in FIGS. 5 and 6 to the second fully closed position shown in FIGS. 7 and 8. In this position, the indexing mechanism of the surgical instrument  35  of the preferred invention is actuated and an automatic sequence of actions occurs beginning with the reciprocation or movement of the first slider  60  proximally as indicated by the arrow in FIG.  20 . 
     In FIG. 20, the first slider  60  has partially moved or retracted into the shaft  92 . This action has released the first and second barbs  107 ,  108  of the distalmost fastener  105  from the constrained condition shown in FIG.  19  and fixably engaged the first barb  107  with the tissue of the inguinal floor  126 . The barbs  107 ,  108  of the distal fastener  105 , when released, snap open to the positions shown in FIG. 20, bending the distalmost fastener  105 . 
     Once actuated, the first slider  60  continues to move distally into the surgical instrument  35  until it returns to the to the initial start position within the shaft  92  as shown in FIG.  21 . When the first slider  60  is at this position, the second slider  70  is automatically released to move or reciprocate distally into the shaft  92  as indicated by the arrow. 
     As shown in FIG. 21, the first slider  60  is at to the initial start position of FIG. 10, fully releasing the distal fastener  105 . The second barb  108  and second leg  111  bias the distal fastener  105  into the portion of the shaft  92  previously occupied by the first feed member  61  of the first slider  60 . This bias further engages the first barb  107  of the distal fastener  105  with the inguinal floor  126 . 
     In FIG. 22, the second slider  70  has automatically retracted distally into the shaft  92  to the first start position and has fully released the second barb  108  of the distal fastener  105  to engage with the tissue of the inguinal floor  126 . The second leg  111  of the distal fastener  105  has also been released from the second slider  70  and both the first and the second legs  110 ,  111  have expanded outwardly within the shaft  92 . 
     Finally, the surgeon releases the trigger  85  which returns to the initial open position of FIG.  1  and withdraws the distal end of the shaft  92  away from the mesh patch  140 , and from the distal fastener  105  that is engaged or attached to the inguinal floor  126 . As shown in FIG. 23, the first and second barbs  107 ,  108  of the fastener  105  of the present invention are firmly planted within the inguinal floor  126  and the first and second legs  110 ,  111 , when released from the shaft  92 , snap back to their original everted shape (FIGS.  9  and  10 ). The mesh patch  140  is fixedly held against the inguinal floor  126  by the first and second legs  110 ,  111  of the fastener  105 . The surgical instrument is now ready to attach the mesh patch  140  at another site. To accomplish this, the surgeon merely repositions the distal end of the shaft  92  at another surgical site and actuates the trigger  85  to place or attach another fastener  105  into the inguinal floor  126 . This process is continued until the mesh patch  140  is satisfactorily attached to the inguinal floor  126 . 
     The Lockout Mechanism 
     The surgical instrument  35  of the present invention (FIG. 1) contains a plurality of fasteners  105 . As the surgeon repeatedly fires the instrument during the attachment of the prosthetic, the number of fasteners  105  stored therein steadily decreases. When the final fastener  105  is placed into tissue, the surgeon has no way of knowing when the instrument is emptied of fasteners  105  and can attempt to fire the empty surgical instrument  35  on tissue. A lockout mechanism of the preferred invention is provided within the surgical instrument  35  to lock the trigger  85  when the surgical instrument  35  is empty. 
     As described previously, the trigger  85  has a lockout arm  88  fixably attached to and extending therefrom. As shown in FIG. 24, actuation of the trigger  85  moves the lockout arm  88  from the initial position of FIG. 3 to a first partially closed position within the handle  40 , and into contact with the lockout wheel  100  to incrementally rotate the lockout wheel  100  in a first direction within the wheel receptacle  48 . The lockout wheel locks the trigger  85  when all of the fasteners are delivered. Each successive actuation of the trigger  85  brings the lockout arm  88  into contact with a successive tooth of the lockout wheel  100   
     In FIG. 24, the trigger  85  has rotated lockout arm  88  counter-clockwise to engage with ratchet tooth  101  extending from the rim of the lockout wheel  100 . A lockout tab  102  is located just above the lockout arm  88  and extends outwardly from the ratchet tooth  101  engaged with the lockout arm  88 . A lockout detent  103  is attached to and extends outwardly from the right handle half  41  towards the viewer to operably engage with the lockout wheel  100 . The lockout detent  103  prevents a rotation of the lockout wheel  100  in a direction opposite to the first direction described above. A small cutout is provided within the lower portion of the lockout wheel  100  to show the outwardly extending end of the lockout detent  103 . 
     FIG. 25 is a distal view taken across cross-section  25 — 25  in FIG. 24, and shows the necessary portions of the key elements so that the reader can understand the operation of the lockout mechanism. The lockout mechanism of the present invention consists of the lockout wheel  100 , the lockout detent  103  and the lockout arm  88  extending from the trigger  85 . Lockout wheel  100  is shown perpendicular to the axis of rotation and has lockout detent  103  operably engaged with a lockout tooth  101  to prevent clockwise rotation of the lockout wheel  100 . The lockout arm of the trigger  85  is cross-sectioned by the cutting plane  25 — 25  and two cross-sections are taken across the lockout arm  88 . To show the movement of the lockout arm  88 , a first section  88   a  is taken across the distal end of the lockout arm  88  when the lockout arm is in the initial position, and a second section  88   b  is taken across the lockout arm  88  to show the position of the lockout arm  88  in each FIG. An arrow is provided to identify the direction of motion of the second section  88   b  of the lockout arm  88 . 
     The lockout wheel  100  of the present invention can have the same number of teeth  101  around its circumference as the surgical instrument  35  has fasteners  105 . When the trigger  85  is fully actuated to place a fastener  105  into tissue, the lockout arm  88  is brought into contact with the lockout wheel  100  to rotate or index the lockout wheel  100  counter-clockwise one tooth  101  as shown in FIG.  26 . When the trigger  85  is released after the actuation, the lockout detent  103  prevents the lockout wheel  100  from rotating clockwise as the lockout arm  88  returns to the initial position  88   a.  Thus, one full actuation of the trigger  85  rotates the locking wheel  100  one tooth  101 , and firing all of the fasteners  105  rotates the lockout wheel  100  one full revolution. 
     FIGS. 27-29 show how the lockout tab  102  operatively locks the lockout arm  88  (and the trigger  85 ) in the fully actuated or closed position as the last fastener  105  is fired. In FIG. 27, the lockout wheel has rotated nearly one full revolution from the first position of FIG.  25 . This is indicated by the new position of the lockout tab  102 . The second section  88   b  of the lockout arm  88  is shown moving upwardly, has just cleared the lockout tab  102 , and is contacting the final lockout tooth  101 . In FIG. 28, the second section  88   b  of the lockout arm  88  is shown in the fully actuated or closed position and the lockout tab  102  has rotated in under the second section  88   b  of the lockout arm  88 . When the trigger  85  is released, the second section  88   b  of the lockout arm  88  moves downwardly to contact the lockout tab  102  and rotates the lockout wheel  100  clockwise to engage tooth  101  with the lockout detent  103  (FIG.  29 ). The engagement with the lockout detent  103  prevents the lockout wheel  100  from rotating clockwise and locks the lockout arm  88 . Thus, in FIG. 29, the second section  88   b  of the lockout arm  88  (and trigger  85 ) is locked in the first partially closed position by the lockout detent  103  which prevents the trigger  85  of the surgical instrument  35  from opening. 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.