Patent Publication Number: US-2023157692-A1

Title: Fastener applicator with interlock

Description:
RELATED APPLICATIONS 
     This application claims the benefit of priority to provisional U.S. Patent Application Ser. No. 61/906,290 filed Nov. 19, 2013, hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure pertains broadly to the field of fasteners and/or applicators. More specifically, the disclosure relates to surgical applicators of implants and/or fasteners, including but not limited to sterilized fasteners such as staples. 
     BACKGROUND 
     Atrial fibrillation is a relatively common condition characterized by a very rapid heartbeat of the left and right atrium. While atrial fibrillation is not normally fatal itself, it has been associated with an increased risk of stroke. It is believed that the rapid heartbeat causes blood to pool in the left atrial appendage which causes emboli that are released into the left atrium from where they can enter the cerebral vasculature, thus causing a stroke. In addition to stroke, the emboli can enter coronary circulation, potentially causing myocardial infarction, or can enter peripheral circulation, potentially causing peripheral vascular disease. 
     The risk of stroke in patients suffering from atrial fibrillation can be reduced in a variety of ways. For example, blood thinning drugs can be used to reduce the risk of clot formation. The use of blood thinners, however, is contraindicated in patients at risk of bleeding disorders. More aggressive treatment protocols have been proposed which involve closing the left atrial appendage. Closure and excision may be performed in open surgical procedures, typically requiring the patient to be placed on bypass and the chest to be opened through the sternum. Alternatively, thoracoscopic and other less invasive procedures have been proposed. U.S. Pat. No. 5,306,234 teaches the performance of heating heart procedures using otherwise conventional surgical techniques. The use of conventional techniques through small chest penetrations while the heart is beating can be difficult to perform. U.S. Pat. No. 5,865,791 describes an intravascular approach where tools are introduced through the vasculature and passed into the left atrium. The tools are used to ablate or fuse the left atrial appendage from the inside using energy, adhesives, or the like. The &#39;791 patent also describes a thoracoscopic procedure where a tether is placed over the neck of the atrial appendage and tied off to achieve isolation. The &#39;791 patent still further suggests other closure elements including sutures, staples, shape-memory wires, biocompatible adhesives, and the like. U.S. Pat. No. 6,488,689 describes a transpericardial procedure where the distal tip of the left atrial appendage is grasped and pulled backwardly through a capture loop which encircles the base of the left atrial appendage. 
     A compliant closure structure for the scaling bodily structures such as the left atrial appendage is described in co-pending, commonly owned U.S. Patent Publication 2007/17260278 (application Ser. No. 11/744,135), the full disclosure of which is incorporated herein by reference in its entirety. The compliant structure described in the &#39;278 publication comprises an elastomeric body having a pair of opposed legs which may be arranged in an oval or a U-shaped configuration to define an opening therebetween. By placing the opening between the legs over the left atrial appendage and aligning it with the base of the appendage, the structure may be closed to provide the desired sealing. To hold the structure closed, a number of discrete, axially spaced-apart tissue penetrating fasteners are arranged along the lengths of each of the legs. By compressing the legs together to press-lit the closure devices, the compliant structure may be closed to provide a compliant seal which effectively isolates the left atrial appendage. 
     The &#39;278 publication describes a particular delivery tool for the compliant closure structure. The delivery tool includes jaws which can be inserted into the legs of the closure structure and actuated to close the jaws in the legs over the left atrial appendage. The jaws further include comb studs which engage and press fit the closure devices in order to hold the compliant structure in its closed, sealing configuration. The studs are intended to be retracted to allow the delivery tool to be removed. 
     Although functional, the delivery tool of the &#39;278 publication has certain shortcomings. For example, the actuation of the jaws and retraction of the comb studs can be performed out of order, increasing the risk that the delivery of the compliant structure will fail. Moreover, positioning and orientation of the delivery tool can be difficult, particularly when the tool is introduced through an intercostal penetration to access the left atrium. Additionally, the jaws in the device of the &#39;278 publication are attached in the axial plane of the device shall. Such a straight line of attachment can make it more difficult to align the jaws with the base of the appendage and across the os (i.e., ostium) of the atrium leading into the appendage. If the closure device is not aligned across the base to completely close the os, gaps or openings (referred to as “cul-de-sacs”) can remain at the site of closure, increasing the risk of thrombus formation in the atrium. The importance of forming a complete seal of the os which is free from such cul-de-sacs is discussed in Sulzberg et al. (2008) Eur. J. Cardiothoracic Surg. 34:766-770. 
     For these reasons, it would be desirable to provide improved delivery tools for use with the tissue closure devices described in U.S. Patent Publication 2007/0260278. It would be further desirable if the delivery tools and methods of their use were compatible with the delivery of other tissue closure devices and for procedures in addition to closure of the left atrial appendage. 
     SUMMARY 
     A surgical applicator for a fastener according to an example embodiment comprises a handle, a first trigger coupled movably with respect to the handle, and a second trigger coupled movably with respect to the first trigger, hut operatively arranged to move in tandem with the first trigger during movement of the first trigger. An interlock is coupled to the second trigger and operatively arranged to selectively prevent movement of the second trigger relative to the first trigger depending on a position of the first trigger with respect to the handle. 
     According to an example embodiment, the interlock permits movement of the second trigger relative to the first trigger when the first trigger is moved from a first position to a second position, and restricts movement of the second trigger relative to the first trigger when the first trigger is not in the second position. 
     According to an example embodiment, a second interlock is coupled to the first trigger and operatively arranged to selectively prevent movement of the first trigger relative to the handle depending on a position of second trigger. 
     According to an example embodiment, a jaw assembly is selectively opened and closed via movement of the first trigger. 
     According to an example embodiment, movement of the second trigger selectively retracts one or more fastener supporting structures of the jaw assembly with respect to at least one jaw of the jaw assembly. 
     According to an example embodiment, the interlock includes a cam follower engaged with a cam channel. 
     According to an example embodiment, the handle includes the cam channel and the second trigger includes the cam follower. 
     According to an example embodiment, the cam channel has a first leg that permits tandem movement of the second trigger with the first trigger during closing of the first trigger and a shoulder that prevents movement of the second trigger relative to the first trigger until the first trigger is closed. 
     According to an example embodiment, the cam channel has a second leg that permits tandem movement of the second trigger with the first trigger during re-opening of the first trigger after the second trigger has been closed relative to the first trigger. 
     According to an example embodiment, the cam channel includes at least one leg formed concentrically with respect to a first pivot about which the first trigger is rotatably coupled to the handle and a transverse portion funned concentrically with respect to a second pivot about which the second trigger is rotatably coupled to the first trigger. 
     According to an example embodiment, the at least one leg includes two legs, and the transverse portion is connected between the two legs. 
     A fastener applicator according to an example embodiment comprises a handle, a first trigger coupled rotatably with respect to the handle, and a second trigger coupled rotatably with respect to the handle. An interlock is disposed with the second trigger and comprises a cam follower engaged in a cam channel that selectively prevents rotation of the second trigger relative to the first trigger depending on a location of the cam follower within the cam channel. The location of the cam follower in the cam channel is set by a position of the first trigger. 
     According to an example embodiment, the handle includes the cam channel and the second trigger includes the cam follower. 
     According to an example embodiment, the cam channel has at first leg that permits tandem movement of the second trigger with the first trigger during closing of the first trigger and a shoulder that prevents movement of the second trigger relative to the first trigger until the first trigger is closed. 
     According to an example embodiment, the cam channel has a second leg that permits tandem movement of the second trigger with the first trigger during re-opening of the first trigger after the so and trigger has been closed relative to the first trigger. 
     A fastener applicator according to an example embodiment comprises a handle, a shaft extending distally from the handle and a jaw assembly at a distal end of the shaft having one or more fastener supporting structures. A first trigger is coupled movably with respect to the handle and to the jaw assembly such that movement of the first trigger relative to the handle selectively closes the jaw assembly. A second trigger is coupled movably with respect to the first trigger, the second trigger coupled to the jaw assembly such that movement of the second trigger relative to the first trigger selectively retracts die one or more fastener supporting structures; and an interlock coupled to the second trigger and operatively arranged to selectively prevent movement of the second trigger relative to the first trigger depending on a position of the first trigger. 
     According to an example embodiment, the interlock permits movement of the second trigger relative to the first trigger when the first trigger is closed and prevents movement of the second trigger relative to the first trigger when the first trigger is open. 
     According to an example embodiment, a second interlock is coupled to the first trigger and operatively arranged to selectively prevent movement of the first trigger relative to the handle depending on a position of second trigger. 
     According to an example embodiment, the interlock includes a cam follower engaged with a cam channel. 
     According to an example embodiment, the handle includes the cam channel and the second trigger includes the cam follower. 
     According to an example embodiment, the second trigger is movable in tandem with the first trigger during movement of the first trigger. 
     A fastener applicator according to an example embodiment comprises a handle, a first trigger movable with respect to the handle between a first position and a second position, and a second trigger movable with respect to the first trigger between an initial position and an actuated position. A first interlock is coupled to the second trigger and operatively arranged to selectively prevent movement of the second trigger relative to the first trigger until the first trigger is moved into the second position. A second interlock is coupled to the first trigger and operatively unarmed to selectively prevent movement of the first trigger relative to the handle until the second trigger is moved into the actuated position. 
     According to an example embodiment, a pair of jaws is included, with the first trigger coupled to the pair of jaws for setting the pair of jaws in an open configuration when the first trigger is in the first position and in a closed configuration when the first trigger is in the second position. 
     According to an example embodiment, one or more fastener supporting structures are disposed with the pair of jaws. The second trigger is coupled to the one or more fastener supporting structures for setting the one or more fastener supporting structures in a deployed configuration when the second trigger is in the initial position and in a retracted configuration when the second trigger is in the actuated position. 
     A method of operating a fastener applicator according to an example embodiment comprises: (i) repositioning a first trigger of the fastener applicator with respect to a handle from a first position to a second position, (ii) moving a second trigger in tandem with the first trigger, (iii) preventing repositioning of a second trigger between an initial position and an actuated position relative to the first trigger with an interlock coupled to the second trigger until the first trigger is moved to the second position, and (iv) repositioning the second trigger to the actuated position relative to the first trigger after the first trigger is moved to the second position. 
     A method of operating a fastener applicator according to an example embodiment comprises: (i) moving a first trigger of the fastener applicator with respect to a handle from a first position to a second position, (ii) preventing movement of a second trigger between an initial position and an actuated position relative to the first trigger with an interlock coupled to the second trigger until the first trigger is moved to the second position, (iii) rearranging a cam follower and a carp channel of the interlock with respect to each other due to the moving of the first trigger to the second position, and (iv) moving the second trigger to the actuated position relative to the first trigger after the first trigger is moved to the second position. 
     A method of operating a fastener applicator according to an example embodiment comprises: (i) moving a first trigger of the fastener applicator with respect to a handle from a first position to a second position, (ii) preventing movement of a second trigger between an initial position and an actuated position relative to the first trigger with a first interlock coupled to the second trigger until the first trigger is moved to the second position, (iii) moving the second trigger to the actuated position relative to the first trigger after the first trigger is moved to the second position, (iv) preventing movement of the first trigger relative to the handle hack to the first position with a second interlock coupled to the first trigger until the second trigger is moved to the actuated position, and (v) moving the first trigger hack to the first position relative to the handle after the second trigger is moved to they actuated position. 
     A method of operating a fastener applicator according to an example embodiment comprises: (i) repositioning a first trigger of the fastener applicator with respect to a handle from a first position to a second position, (ii) closing a jaw assembly coupled to the handle of the fastener applicator due to movement of the first trigger to the second position, (iii) preventing repositioning of a second trigger between an initial position and an actuated position relative to the first trigger with an interlock coupled to the second trigger until the first trigger is moved to the second position, (iv) repositioning the second trigger to the actuated position relative to the first trigger after the first trigger is moved to the second position, and (v) retracting one or more fastener supporting structures comprising at least one protrusion movably extendable and retractable with respect to at least one jaw of they jaw assembly of the fastener applicator due to repositioning of the second trigger to the actuated position. 
     According to an example embodiment, the fastener applicator comprises a second interlock coupled to the first trigger and the method further comprises preventing movement of the first trigger from the second position to the first position with the second interlock until the second trigger is moved to the actuated position relative to the first trigger, and repositioning the first trigger from the second position back to the first position after the second trigger is moved to the actuated position relative to the first trigger. 
     According to an example embodiment, the interlock includes a cam follower engaged with a cam channel. 
     According to an example embodiment, rotating the first trigger front the first position to the second position includes traversing the cam follower along a first leg of the channel. 
     According to an example embodiment, the first leg is formed concentrically with respect to a pivot about which the first trigger rotates. 
     According to an example embodiment, rotating the second trigger to the actuated position relative to the first trigger includes traversing the cam follower along a portion of the channel transverse to the first leg. 
     According to an example embodiment, the handle includes the cam channel and the second trigger includes the cam follower. 
     According to an example embodiment, rotating the first trigger from the first position to the second position including moving the second trigger in tandem with the first trigger. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG.  1    is a perspective view of a closure device applicator constructed in accordance with to an example embodiment of the present disclosure; 
         FIG.  2    is a partial cross-sectional elevation view of the closure device applicator of  FIG.  1   , shown with the jaws open and rotated 90° relative to the position shown in  FIG.  1   ; 
         FIG.  3    is a partial, cross-sectional elevation view of the device applicator similar to  FIG.  2   , shown with the first trigger closed relative to the handle in order to close the jaws, and the second trigger open (or spaced apart) with respect to the first trigger; 
         FIG.  4    is a partial, cross-sectional elevation view of the closure device applicator similar to that shown in  FIGS.  2  and  3    with the second trigger closed relative to the first trigger demonstrating a retraction of the closure device-engaging studs; 
         FIG.  5    is a partial, cross-sectional elevation view of the closure device applicator of  FIGS.  2 - 4   , shown with the first trigger re-opened with respect to the handle in order to open the jaws while the closure device-engaging studs remain retracted; 
         FIG.  6 A- 6 D  illustrate the movement of the jaw and stud engagement with the closure devices of a tissue closure device according to an example embodiment of the present disclosure; 
         FIG.  7    illustrates an exemplary mechanism by which the closure device-engaging studs are retracted within the jaws according to an example embodiment of the present disclosure; 
         FIG.  8    illustrates an interlock formed between a cam channel, slot, or groove in a handle of the applicator of  FIG.  1   , shown in cross-section, and a cam follower projecting from a second trigger of the applicator of  FIG.  1   , shown in a perspective and exploded view orientation according to an embodiment of the present disclosure; 
         FIGS.  9 A- 9 E  illustrate various positions of the cam follower of  FIG.  4    along the cam channel of the interlock as first and second triggers of the applicator are moved through the configurations depicted in  FIGS.  2 - 5   ; 
         FIG.  10    illustrates operation of the interlock of  FIG.  8    with respect to the first and second triggers of the applicator of  FIG.  1   ; and 
         FIG.  11    illustrates use of the applicator according to an example embodiment of the present disclosure, wherein the applicator is used for closing a closure device over a left atrial appendage. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Embodiments of the present disclosure provide alternative and improved apparatuses, systems, and methods for deploying one or more closure devices or fasteners to tissue. An exemplary tissue structure of a patient at risk of stroke or other adverse events resulting from emboli released into circulation from the left atrial appendage, may include the left atrial appendage. Patients benefiting front the exemplary procedures disclosed herein will at least partially include those suffering from atrial fibrillation which can cause clot and thrombus formation in the left atrial appendage, thus increasing the chance of emboli release. 
     Exemplary embodiments of the present disclosure provide a mechanical closure device applicator for introducing the fastener over the tissue structure, which fastener is left in place in order to close and/or seal the tissue structure. A portion of the tissue structure extending beyond the fastener may then be cut, excised, or otherwise removed, although this may be left to the physician&#39;s preference. In one embodiment, the tissue fastener comprises a compression body having at least two opposed, compliant tissue-engaging surfaces which are placed over opposite sides of the tissue structure. In this embodiment, the tissue-engaging surfaces are held together by a plurality of axially spaced-apart tissue-penetrating fasteners, which extend from one of the surfaces, through the intermediate tissue, and into the other surface to both hold the compression body in place and to apply a desired level of compression force, which is determined by both the softness of the compression body and the distance between the surfaces when they are fully attached. A well may be provided in the compression body around the tissue-penetrating barb of the fastener such that a gasket seal is formed by the compression body around the puncture site in the tissue. A stabilizing lip may be provided in one leg of the compression body to prevent a rolling motion of one leg with respect to another leg of the compression body in order to keep the two opposing soft members linearly aligned. More detailed descriptions of fasteners suitable for use with embodiments of the present disclosure are found in patent publication U.S. 2007/0260278, the full disclosure of which has been previously incorporated herein by reference. 
     Referring now to  FIG.  1   , a fastener applicator  10  constructed in accordance with various embodiments of the present disclosure comprises a shaft  12  having a handle assembly  14  at its proximal end, and a jaw assembly  16  at a distal end, when individual jaws  18  and  20  are adapted to carry a fastener  22 , as best illustrated in  FIGS.  6 A- 6 D . The fastener  22  is shown in an example embodiment to have a U-shaped configuration which defines a V-shaped region  24  for receiving the left atrial appendage or other tissue structure when the jaws are open as shown in  FIGS.  1 ,  2   , and  6 A. A plurality of studs  26  are formed along the inner surfaces of each jaw  20  and  18  to engage tissue-penetrating fasteners which comprise penetrating components  28  and receptacle components  30 , as best shown in  FIG.  6 A . The handle assembly  14  will include a handle  32 , a first trigger  34 , and a second trigger  36 . 
     Referring now to  FIGS.  2  and  6 A , the fastener applicator  10  is shown in its shelf or delivery configuration with the fastener  22  received over the jaw assembly  16  and the V-shaped opening  24  in the device ready to be placed over a tissue structure such as the left atrial appendage (see  FIG.  10   ). The triggers  34  and  36  are each respectively movable between an initial or first position and an actuated or second position. As will be discussed in more, detail below, the first trigger  34  is movable between its respective positions relative to the handle  32 , while the second trigger  36  is movable between its respective positions relative to the first trigger  34 . In one embodiment, in their respective first positions, the first trigger  34  and the second trigger  36  are initially in a fully open position, that is, pivoted fully away from the handle  32 . For this reason, it is to be understood that any mention of “opening” the first trigger  34  refers more generally to moving the first trigger  34  toward its first or initial position, white any mention of “closing” the first trigger  34  or the second trigger  36  refers more generally to moving the first trigger  34  or the second trigger  36  towards its respective second or actuated position. 
     After the fastener  22  is advanced over the left atrial appendage or other target tissue structure, the jaws  18  and  20  are closed by manually pulling the first trigger  34  toward the handle  32 , as shown in  FIGS.  3  and  6 B . The first trigger  34  is mounted on a pin or pivot  40 , which is shown to be fixedly secured to the handle assembly  14 , thereby rotatably coupling the first trigger  34  to the handle  32 . Closing the first trigger  34  with respect to the handle  32 , that is, pivoting about the pivot  40  from the first position of the first trigger  34  to the second position, proximally retracts the rod  42  which is linked to the first trigger  34  by a pin or pivot  41  and a lever  43 . The rod  42  is attached to a pin  44  ( FIG.  6 B ) which is pivotally attached to the proximal ends of the jaws  18  and  20  and proximally retracts the jaws so that they are closed by the movement of slots  46  over pins  48  in an end frame  50  attached to a stationary sleeve  52 . When the jaws  18  and  20  are closed, the studs  26  engage the tissue penetrating components  28  and the tissue penetrating receptacles  30  so that they engage and lock with each other, thus closing the two legs of the fastener  22 , as shown in  FIG.  6 B . 
     The second trigger  36  may be mounted on the pin  41  so that the second trigger  36  moves, actuates, or closes with respect to the handle  32  in tandem with the first trigger  34 . In this way, the second trigger  36  is rotatably coupled to the handle  32 , although indirectly via the pin  41  and the first trigger  34 . By “in tandem” it is meant that movement of the first trigger  34  translates at least partially into corresponding movement of all or portions of the second trigger  36 . In the illustrated embodiment, movement of the first trigger  34  causes a substantially equivalent amount of rotational movement of the second trigger  36 , although there could be gears, linkages, springs, or the like to cause a lesser or greater degree of movement of the second trigger  36  to result from corresponding movement of the first trigger  34 . 
     The applicator  10  may optionally include an interlock  60  in some embodiments. According to the illustrated embodiment, as the first trigger  34  and the second trigger  36  are moved in tandem, a ratcheting tooth surface  62  of the interlock  60  is closed against pins  64 , as shown in  FIG.  3   , so that the first trigger  34  cannot be ne-opened once the jaw assembly  16  has been closed, either completely or to a certain degree of closure or spacing between the jaws. This is advantageous as described above, since the jaws should not be completely opened prior to retracting the studs  26  by closing the second trigger  36 , as will be described below. The ratcheting tooth surface  62  can include any number of ratchets or notches such that the first trigger  34  can be progressively closed (i.e., brought into approximation of the handle  32 ) by more fully driving the ratcheting tooth surface  62  along the pins  64  in the direction of closure for the first trigger  34  (e.g., from the configuration of  FIG.  2    to the configuration of  FIG.  3   ). 
     Additionally, as the first trigger  34  is moved to its actuated, closed, or second position (i.e., moved or actuated to the configuration of  FIG.  3   ) in order to close the jaws  18  and  20  of the jaw assembly  16 , a corner  66  (see  FIG.  2   ) of the interlock  60  will engage an inclined surface  68  on a clicker pin  70  to disengage the clicker pin  70  from a holding pin  72 , thus allowing a spring  74  to push the pin  70  downward so that a bottom surface  76  thereof strikes the bottom of the handle  32 , thus causing a loud click to audibly alert the physician that the jaws have been closed and the interlock  60  has been engaged. This audible confirmation indicates to the physician or other medical personnel that the fastener  22  has been closed and that the studs  26  can be retracted. 
     The studs  26  are initially in an extended configuration, as shown in  FIGS.  2 - 3  and  6 A- 6 B , and then retracted by closing second trigger  36  against the first trigger  34 , as shown in  FIGS.  4  and  6 C . Closure of the second trigger  36  relative to the first trigger  34  draws the outer sleeve  54  proximally over the stationary sleeve  52  which draws pull wires  80  proximally to full stud combs  84  or other fastener supporting structures, proximally, as shown in  FIG.  7   . The stud combs  84  are mounted on pins  86  which travel in slots  88  formed in each of the jaws  18  and  20 . The second trigger  36  is pivotally mounted on, or rotatably coupled to, the first trigger  34  by the pin  41  and is coupled to the stationary sleeve by pins  90  and  91  and a lever  92 . It is to be appreciated that the studs  26  can take other shapes or arrangements and/or that other fastener supporting structure (i.e., structures capable of supporting the fasteners  22  during closing and engaging thereof) can be included in lieu of the studs  26  that are either disengaged from or engaged to the fastener  22  upon intentional closure or movement of the second trigger  36 . For example, in lieu of a plurality of individual studs  26 , a supporting structure in the form of a single unitary rail supporting all of the components  28  can be included in one embodiment. 
     Movement of the second trigger  36  relative to the first trigger  34 , e.g., closure of the second trigger  36 , disengages the interlock  60  by engaging a ramped surface  94  attached to the interlock  60  against a fixed pin  96  in the second trigger  36 . In this way, the interlock  60  selectively permits or prevents movement, e.g., opening, of the first trigger  34  depending on a position of the second trigger  36 . In other words, movement of the second trigger  36  to its corresponding second position, relative to the first trigger  34 , releases the interlock  60 . The pin  96  follows the path shown in broken line in  FIG.  3    to engage the surface  94 . The ramped surface  94  is caused to move downwardly, pulling the ratchet teeth  62  away from the fixed pins  64 , as shown in  FIGS.  4  and  5   . The triggers  34  and  36  are now ready to be opened in order to open the jaws, as will now be described. 
     Referring now to  FIGS.  5  and  7 C , the jaws  18  and  20  may be opened by releasing manual compression on the first and second triggers  34  and  36 , allowing spring  98  which was compressed during closure of the first trigger  34  to push rod  42  (attached to pivot  44 ) distally forward, opening the jaws and leaving the fastener  22  in place. 
       FIG.  8    shows a cross-section of the handle  32  as well as the second trigger  36  exploded therefrom. An interlock  100  is included between the handle  32  and the second trigger  36  to selectively permit and prevent rotational movement of the second trigger  36  with respect to the first trigger  34 . The first trigger  34  does not form a part of the interlock  100  in the illustrated embodiment, and therefore is not illustrated in  FIG.  8   . However, it is to be understood that the first trigger  34  in the embodiment of  FIG.  8    would be nevertheless be secured to the second trigger  36  at the pivot  41  as described herein with respect to the other Figures. Additionally, the shaft  12  and the jaw assembly  16  are not illustrated in some Figures, including  FIG.  8   , but can be included as described herein with respect to the other Figures. 
     More specifically, the interlock  100  includes a cam follower  102  and a channel  104 . In the illustrated embodiment, the cam follower  102  is formed as a protrusion or projection extending from or otherwise coupled to the second trigger  36 , and is preferably round in cross section but alternatively may be of other shapes. The cam follower  102  can be integrally formed with the second trigger  36  or affixed thereto as a separate component. The channel  104  may be formed as a groove, depression, notch, slot, or the like in the handle  32 . The follower  102  is configured to engage with and/or travel along the channel  104  (and thus will be restricted to movement within the channel  104 ) when the second trigger  36  is assembled with the handle  32 . It is noted that the applicator  10  can include other exemplary embodiments of a single follower  102  and a single channel  104  if desired, but for symmetry, balance, etc., the second trigger  36  may include two cam followers  102  (e.g., another follower  102  hidden from view in  FIG.  8    on the opposite lateral side of the second trigger  36  and mirroring the illustrated one of the followers  102  about a plane bisecting the second trigger  36 ), and the handle  32  may correspondingly include two cam grooves  104  (e.g., another channel  104  located in the half of the handle  32  not shown in  FIG.  8   , which mirrors the illustrated channel  104  about the plane used to form the cross-sectional view of the handle  32  in  FIG.  8   ). 
     The mechanical coupling of the follower  102  to the second trigger  36  prevents rotation of the second trigger  36  relative to the first trigger  34  when the follower  102  abuts against the walls or shoulders defining the channel  104 . For example,  FIGS.  9 A- 9 E  show various positions of the follower  102  (without the second trigger  36  for clarity) corresponding to the various combinations of positions of the first and second triggers  34  and  36  of the applicator  10 . That is, for example, the position of the follower  102  in  FIG.  9 A  corresponds to an initial, shelf, or delivery configuration of the applicator  10  shown in  FIG.  2   , i.e., before the triggers  34  or  36  have been actuated. 
     In the position of  FIG.  9 A , rotation of the second trigger  36  is prevented by interference of the follower  102  with a shoulder  106  of the channel  104 . That is, movement of the second trigger  36  relative to the first trigger  34  occurs about the pin  41 , which rotationally couples the second trigger  36  to the first trigger  34 . Thus, rotation of the second trigger  36  about the pin  41  (if unblocked) would result in the cam follower  102  following an arc defined by a circular path concentric with the pin  41 , e.g., illustrated as a circle  107  in  FIG.  10   . Front  FIG.  10   , it is clear that rotational movement of the cam follower  102  along an arc defined by the circle  107  is not possible due to interference between the cam follower  102  and the shoulder  106 . Accordingly, rotation of the second trigger  36  about the pin  41  relative to the rust trigger  34  is prevented by the interference between the cam follower  102  and the shoulder  106 . 
     The channel  104  is shaped with a leg  108 , which permits the second trigger  36  to travel in tandem with the first trigger  34  as the first trigger  34  is moved toward its second position, i.e., rotated about the pivot  40  toward the configuration of the applicator  10  shown in  FIG.  3   . That is, again referring to  FIG.  10   , tandem movement of second trigger  36  due to movement of the first trigger  34  would result in the cam follower  102  traveling along an arc defined by a circular path concentric with the pivot  40 , illustrated in  FIG.  10    by a circle  109 . The first leg  108  is arranged to lie substantially along such an arc formed by the circle  109 , thereby enabling the cam follower  102  to travel along the leg  108  during rotation of the first anti second triggers  34  and  36  about the pin  40 . 
       FIG.  4 B  illustrates the position of the follower  102  in the channel  104  when the first trigger  34  is rotated partially toward the configuration of  FIG.  3   , e.g., with ratcheting tooth surface  62  of the interlock  60  at most only partially driven along and engaged with the pins  64 . At the position of  FIG.  9 B , the shoulder  106  continues to prevent rotation of the second trigger  36  by blocking movement of the follower  104  in the direction necessary to rotate the second trigger  36 . 
       FIG.  9 C  illustrates the position of the follower  102  after the trigger first  34  has been moved to the configuration of  FIG.  3    and the ratcheting tooth surface  62  of the interlock  60  is fully driven along and engaged with the pins  64 . It can be appreciated in view of  FIGS.  3  and  9 C  that rotation of the second trigger  36  becomes possible at this position because the shoulder  106  no longer abuts the follower  102 . Alternatively stated, it is to be appreciated that tandem movement of the second trigger  36  with the first trigger  34  has shifted the position of the cam follower  102  and the pin  41  relative to the channel  104  (since the pin  41  and the cam follower  102  are directly coupled to the second trigger  36  in the illustrated embodiment). It is to be further understood than this shifting of the position of the pin  41  and the cam follower  102  has also moved the location of the circle  107  to align with a portion  110  of the channel  104  that is transverse to the leg  108  and arranged along an arc that is concentric with respect to the pin  41 . 
     In view of the foregoing it can be seen that the position of the first trigger  34  selectively prevents or permits rotation of the second trigger  36 . Again, movement of the first trigger  34  causes tandem movement of the second trigger  36 , which results in the follower  102  first traversing along the leg  108  of the channel  104 . However, movement of the second trigger  36  relative to the first trigger  34  is prevented due to interference between the cam follower  102  and the shoulder  106 . Relative movement of the second trigger  36  with respect to the first trigger  34  is thus prevented until the cam follower  102  is moved to a position at which the cam follower  102  no longer abuts the shoulder  106 .  FIG.  9 D  shows the position of the follower  102  after movement of the second trigger  36  relative to the first trigger  34  is permitted and the second trigger  36  has also been actuated to its second position, thereby corresponding to the configuration of the applicator  10  shown in  FIG.  4   . 
     The channel  104  is shaped with another leg  112  that enables the follower  102  to continue to traverse the channel  104  such that the second trigger  36  can again move in tandem with the first trigger  34  as the first trigger  34  is moved to reopen the jaw assembly  16 , i.e., as the first trigger  34  is moved back toward its first position. It is to be appreciated that the leg  112 , similar to the leg  108 , is formed along an arc that is concentric to the pivot  40 . This accordingly enables the cam follower  102  to travel along the leg  112  as the second trigger  36  moved in tandem with the first trigger  34  as the first trigger  34  is rotated about the pivot  40 .  FIG.  9 E  accordingly shows the corresponding location of the follower  102  in the channel  104  when the first trigger  34  is returned to its first or initial position, which may correspond to the applicator  10  assuming the configuration of  FIG.  5    in which the jaw assembly  16  is again opened. 
     It is to be appreciated that the channel  104  can take other shapes in other embodiments depending on the desired relative movement of the first and second triggers  34  and  36  relative to each other and to the handle  32 . More specifically, the channel  104  will include ii leg or portion for each optionally desired stage of movement of the first trigger  34  and of the second trigger  36 , with the legs and/or portions of the channel  104  being concentric with respect to the pivot about which rotation is desired for each stage of movement. Thus, in order to sequentially permit (i) tandem movement of both of the first and second hissers  34  and  36  about a first pivot (e.g., the pivot  40 ), then lip movement of the second trigger  36  relative to the first trigger  34  about a second pivot (e.g., the pivot  41 ), and then (iii) tandem movement of the first and second triggers  34  and  36  again with respect to the first pivot, the channel  104  will include two legs (e.g., the legs  108  and  112 ) that are spaced apart hut both concentric with respect to the first pivot (e.g., the pivot  40 ), which enables the movements of stages (i) and (iii), and a transverse portion (e.g., the portion  110 ) connecting between the two legs (e.g., the legs  108  and  112 ) that is formed concentrically with respect to the second pivot (e.g., the pivot  41 ) to enable the movement of stage (ii). 
     From the above description and the  FIGS.  9 A- 9 E , it is clear that the interlock  100  accordingly prevents rotation of the second trigger  36  until after the trigger first  34  is first rotated, preferably fully rotated (i.e., from a first position to a second position). Since full rotation of the first trigger  34  (e.g., as shown in  FIG.  3   ) corresponds to the closing of the jaw assembly  16 , the interlock  100  thus advantageously selectively prevents retraction of the studs  26  (due to rotation of the second trigger  36 ) until after the jaw assembly  16  is closed. Referring again to the above description, it is again noted that the interlock  60  is released depending on the position of the second trigger  36  relative to the first trigger  34 . Thus, the location of the first trigger  34  is first used to release the interlock  100 , selectively permitting movement of the second trigger  36  relative to the first trigger  34 , and thereafter the location of the second trigger  36  relative to the first trigger  34  is used to release the interlock  60 , which selectively permits movement of the first trigger  34  relative to the handle  32  back toward the initial position for the first trigger. In this way, the aforementioned order of the steps of (1) closing the jaws, (2) retracting the studs, and (3) opening the jaws is maintained and ensured by use of either or both of the interlocks  60  and  100 . 
     It is to be appreciated that the interlock  100  can take other forms in non-illustrated embodiments. For example, in one embodiment the channel  104  is alternatively formed with the second trigger  36  and the follower  102  with the handle  32 . In another embodiment, part of the channel  104  is formed in one of the handle halves while the other is formed in the other of the handle halves. 
     Referring now to  FIG.  11   , one specific example of use is illustrated. In this example, the fastener applicator  10  is used to deliver one of the fasteners  22  over the base of a left atrial appendage LAA in an open chest, beating heart procedure. The sternum S is opened, spreading the ribs R to provide a working space over the heart. After opening the pericardial sack, the heart may be lifted and turned, for example using a sheet of gauze or other material which is placed behind the heart, to expose the left atrial appendage within the opening as shown in  FIG.  10   . After the left atrial appendage LAA is exposed, the jaws  18  and  20  of the fastener applicator are placed around the base of the appendage by manipulating the shaft  12 , as shown in  FIG.  10   . The angle of the jaws  18  and  20  relative to the shaft, typically about 15°, is highly advantageous as it allows the jaws to engage the base of the left atrial appendage so that they are generally parallel with the os between the appendage and the left atrium LA. If the plane of the jaws was aliened with the shaft, it would be difficult to achieve this orientation and the risk of closing the appendage and leaving a cul-de-sac (an open space beyond the us and into interior of the left atrial appendage) is greatly increased. Such cul-de-sac is problematic as it can be a source of clotting and, if created, must be closed in the same or later procedure. Once the jaws  18  and  20  properly position the fastener  22  about the base of the left atrial appendage, the jaws are actuated and the fastener deployed as described previously. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, hut that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.