Abstract:
The invention relates to tacking devices for use in minimally invasive surgery that have a quantity indicator on a distal end that can be seen through a scope and that show a number of fasteners remaining in the device. A surgeon can watch the delivery of fasteners while simultaneously seeing f a number of fasteners remaining. This allows a hernia mesh to be properly fixed into place without going astray during the delicate initial placement procedure and also for even spacing of the fasteners on the mesh. The patient&#39;s post-operative recovery progresses well, and excessive pain is avoided. Methods of the invention include viewing the surgical site via the scope while also viewing the indicator via the scope.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of, and priority to, U.S. Provisional Patent Application Ser. No. 61/776,009, filed Mar. 11, 2013, the contents of which are incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention generally relates to surgical devices for use in minimally invasive surgery and particularly to devices that have a quantity indicator on a distal end. 
       BACKGROUND 
       [0003]    Some surgical procedures involve delivering a series of clips such as tacks, staples, or sutures to a surgical site within a patient. For example, hernia repair can include fastening a type of prosthesis known as a hernia mesh to the tissue within a patient&#39;s abdomen. One approach involves performing a laparoscopic procedure to go into the abdomen with a surgical tacking device and deliver a series of clips to fix the mesh in place. A surgeon makes an incision and inserts surgical implements as well as an endoscope or laparoscope—a small telescope with a camera attached—to see the target site. These methods suffer from shortcomings that are associated with risks of complication and patient pain. 
         [0004]    For example, while the mesh is being unfurled or is first tentatively positioned, it may be particularly important to deliver several fasteners in rapid succession. If the device runs out of fasteners during this step, the mesh could go astray in an unpredictable manner. The mesh may fold or flop into positions that are unmanageable and may result in bowel adhesions and post-operative pain. Unfortunately, if a surgeon looks away from the scope to examine the tacking device, that can also result in loosing orientation of the surgical field which result in prolonging of the operation and may also result in surgical errors. Also, once the mesh is first tacked into the proper position, the remaining fasteners ideally should be evenly distributed around the edges of the mesh. This can only happen if the surgeon knows the number of fasteners remaining and therefore the number of fasteners to place along each edge. If the mesh is not fastened properly—if an edge is not fastened well enough or if the positioning goes astray—the repair can fail and hernia recurrences may require the procedure to be repeated. 
       SUMMARY 
       [0005]    The invention provides a surgical tacking device with an indicator that can be seen through the scope that shows a number of fasteners remaining in the device. A surgeon can watch the delivery of fasteners by a distal tip of the device while simultaneously seeing an indication of a number of fasteners remaining within the device. This allows the surgeon to, while placing a hernia mesh, see a direct indication of how many fasteners remain to be used. The surgeon thus knows if he is equipped to provisionally place the mesh and tack it down. Additionally, once a mesh is properly placed, the surgeon—without taking his eyes from the scope—can get a count of the number of fasteners remaining and thus decide how best to space the fasteners around the mesh. This allows a hernia mesh to be properly fixed into place without going astray during the delicate initial placement procedure. Since the surgeon knows how many fasteners are remaining, he can space those fasteners evenly about the hernia mesh and will not run out of fasteners with one edge of the mesh not yet fastened in place. Since this also allows a hernia mesh to be fastened into place with fasteners that are spaced evenly without repeatedly entering the surgical sites with multiple instruments, unwanted surgical complications are avoided. The patient&#39;s post-operative recovery progresses well, and excessive pain is avoided. Additionally sometimes hernia fasteners are misfired and fall down over the bowel. This can lead to bowel perforation and long term complications. The ability to count fired fasteners while visually inspecting the spot on the mesh that was targeted for fastening can give an indication if the fastener has indeed been misfired and whether the surgeon should search for it over the bowel and extract it out. 
         [0006]    In certain aspects, the invention provides a surgical fastening device that has a handle with a trigger, an elongated shaft extending from the handle with a carrier portion disposed at a distal portion of the shaft, and a plurality of fasteners disposed within the carrier portion. The device includes an indicator on the distal portion of the shaft that shows a number of the plurality of fasteners that remain within the carrier portion. Preferably, operation of the trigger causes the device to deliver one of the plurality of the fasteners and to decrement by one the number indicated by the indicator. The indicator may have a linkage (e.g., a mechanical, electrical, digital, or optical linkage) between a visible marker disposed on a surface of the shaft and a location of a marker element disposed within the carrier portion. The indicator may include a visible marker, which can be configured to correspond to one of a set of graduations extending along the distal portion of the shaft. The indicator may include a visible marker configured to assume only certain discrete, pre-determined positions on a surface of the shaft. In some embodiments, the visible marker is offset from the graduations to compensate for parallax that arises when viewing the indicator (i.e., through a scope or camera device such as a laparoscope or endoscope). In certain embodiments, the indicator may include a ring that extends around the shaft and displaces along the shaft to indicate a number of fasteners remaining. This way, the ring may indicate the number when viewed from any approach angle. 
         [0007]    In certain embodiments, the indicator includes a marker element disposed within the carrier portion and an electronic display. The electronic display may include a light (e.g., an LED), an LCD display, or similar on the distal portion. The electronic display may be, for example, a monitor coupled to an endoscopic camera (e.g., receiving information for the indicator via an electronic coupling to the marker element or by directly viewing the visible marker with the endoscopic camera). 
         [0008]    In another embodiment, the indicator includes a color-coded portion. Any suitable color can be used. For example, a progressive color change can indicate a number of fasteners remaining (e.g., green is full; blue is partially full; red is almost empty (last 3 fasteners); and black is empty). Since the indicator is always located in the same spot (e.g., on the very distal tip), the surgeon does not need to direct the camera to a different location. Additionally, this embodiment may find particular application in settings where different surgeons are familiar with different numeral systems (e.g., where not all surgeons are primarily familiar with Arabic numerals). 
         [0009]    In related aspects, the invention provides methods of performing surgical procedures that include using a surgical fastening device that has a handle with a trigger, an elongated shaft extending from the handle with a carrier portion disposed at a distal portion of the shaft, and a plurality of fasteners disposed within the carrier portion. The device includes an indicator on the distal portion of the shaft that shows a number of the plurality of fasteners that remain within the carrier portion. Preferably, methods include operating the trigger to deliver one of the plurality of the fasteners to a surgical site and to decrement by one the number shown by the indicator. Methods of the invention include viewing the surgical site via a scope (e.g., through an endoscope or on a monitor of a laparoscope) while also viewing the indicator via the scope. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  depicts a fastening device for delivering fasteners of different sizes. 
           [0011]      FIG. 2  shows an indicator on a surgical device. 
           [0012]      FIG. 3  gives a view of components of a handle of a fastening device. 
           [0013]      FIG. 4  illustrates the function of the fastener feeder. 
           [0014]      FIG. 5  is an exploded view of the structure of the fastener feeder mechanism. 
           [0015]      FIG. 6  depicts a pre-formed fastener according to certain embodiments. 
           [0016]      FIG. 7  reveals a applicator section. 
           [0017]      FIG. 8  shows a fastener loaded into the applicator section. 
           [0018]      FIG. 9  depicts the operation of a fastening device of certain embodiments. 
           [0019]      FIG. 10  shows a step in operation of the fastening device from  FIG. 9 . 
           [0020]      FIG. 11  gives another step in operation of the fastening device from  FIG. 9  &amp;  FIG. 10 . 
           [0021]      FIG. 12  depicts a step in the operation of the comb driver mechanism of a fastener feeder. 
           [0022]      FIG. 13  shows another step in the operation of the comb driver mechanism. 
           [0023]      FIG. 14  gives a next step in the operation of the comb driver mechanism. 
           [0024]      FIG. 15  illustrates a step in the operation of the comb driver. 
           [0025]      FIG. 16  shows a step in the operation of the comb driver mechanism. 
           [0026]      FIG. 17  shows a carrier loaded with long anchor-style fasteners. 
           [0027]      FIG. 18  gives a picture of a stretchable fastener. 
           [0028]      FIG. 19  shows a carrier loaded with tack-style fasteners. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The invention provides devices and methods for minimally invasive (e.g., laparoscopic) surgical fixation. Any surgical fixation methods may be benefited by a device of the invention. In some embodiments, a device is provided for hernia repair by mesh fixation. Techniques and devices for hernia mesh fixation that may be modified to benefit through use of the invention include those described in Gillian, et al., 2002, Laparoscopic Incisional and Ventral Hernia Repair (LIVH): An Evolving Outpatient Technique, JSLS 6(4):315-322; U.S. Pub. 2013/0012961 to Reeser; U.S. Pub. 2012/0265218 to Chen; and in U.S. Pub. 2010/0318107 to Mizrahy, the contents of each of which are incorporated by reference in their entirety for all purposes. 
         [0030]    A hernia mesh can be affixed to tissue through the use of sutures, pre-formed sutures, clips, tacks, anchors, staples, and other such fasteners. Such fasteners are referred to herein as clips. Exemplary fasteners are described in U.S. Pat. No. 8,343,176 to Criscuolo; U.S. Pat. No. 8,114,099 to Shipp; U.S. Pat. No. 5,830,221 to Stein; U.S. Pub. 2011/0130774 to Criscuolo; U.S. Pub. 2011/0022065 to Shipp; and U.S. Pub. 2010/0327042 to Amid, the contents of each of which are incorporated by reference. 
         [0031]      FIG. 1  depicts a fastening device  100  for delivering fasteners for hernia mesh fixation. Device  100  generally includes a handle  102  connected through shaft  103  to applicator section  101 . Handle  102  will generally include a trigger  105 . Squeezing trigger  105  delivers one fastener into tissue. Device  100  includes a carrier portion  151  for a holding plurality of fastener  250 . The fastener carrier portion  151  is operably connected to the shaft  103  by any suitable attachment mechanism. For example, a portion of shaft  103  can extend into carrier portion  151  or a portion of carrier portion  151  can extend into shaft  103 . Additionally, the fitting between shaft  103  and carrier portion  151  can be threaded, press-fit, use adhesives, or a combination thereof. Shaft  103  and carrier portion  151  can be co-molded or manufactured as a single piece. The connection between shaft  103  and carrier portion  151  is operable in that operation of trigger  105  delivers a fastener from carrier portion  151 . Fastening device  100  can provide variable depth fastening by allowing for the switching of a cartridge-style carrier portion  151  wherein each cartridge contains a different length of fastener  250 . Another way that device  100  can provided variable depth fastening is by allowing for the loading of different sizes of fastener  250  to a single device. Preferably, switching from one depth to another does not require any adjustment at the operation handle. For example, the first 4 of fastener  250  may be long with the rest being short (or a mixture of multiple sizes). In some embodiments, device  100  uses a stretchable fastener  250  (see, e.g.,  FIG. 18 ) and the fastener  250  penetration depth is adjusted through the stretching of fastener  250 . 
         [0032]    In some embodiments, carrier portion  151  is a replaceable cartridge. A replaceable cartridge can be provided that is pre-loaded with a selection of fastener  250 . Replaceable cartridges adaptable for use with the invention are described in U.S. Pat. No. 5,356,064 to Green, the contents of which are incorporated by reference. One important benefit of indicator  141  relates to a replaceable cartridge. Where the cartridge carries the indicator of a number of clips remaining, replacing the cartridge does not require the indicator to be reset. 
         [0033]      FIG. 2  shows an indicator  141  that shows a number of fastener  250  remaining in device  100 . Indicator  141  may be presented in any form that reveals a number of fasteners  250  remaining. The indicator may be positioned such that, when a surgeon is observing carrier portion  151  and applicator section  101  within a patient, the surgeon may also simultaneously observe indicator  141 . For example, if a scope (e.g., laparoscope or endoscope) is being used to observe delivery of fasteners  250 , indicator  141  is also visible through the scope. The mechanics of carrier portion  151  within shaft  103  preferably includes a marker element  947  (first shown in  FIG. 4 ) that moves along shaft  103  each time a fastener  250  is delivered. As discussed in greater detail below with respect to  FIG. 4 , a location of marker element  947  corresponds to a present number of fasteners  250  in device  100 . A location of marker element  947  can be used by indicator  141  to reveal a number of fasteners remaining in device  101 . 
         [0034]    In some embodiments, indicator  141  includes a visible marker  145  on carrier portion  151 . In some embodiments, indicator  141  is anywhere on device  100 , for example, at any position along shaft  103 . In certain embodiments (not depicted), indicator  141  is an electronic device that relays information (e.g., a digital signal) to a receiver unit located outside of a patient (e.g., a computer or monitor). As shown in  FIG. 2 , indicator  141  may be embodied in a visible marker  145  configured to travel along a travel slot  143 . Visible marker  145  may be an annular band, or ring, that extends around shaft  103 . An annual band marker  145  may include a cylindrical piece of material (e.g., plastic, metal, other polymer) mounted on an extension that passes through travel slot  143 . 
         [0035]    In certain embodiments, indicator  141  includes a display element near applicator section  141 . A display element can include a window or similar display that contains, for example, a numeral. The numeral can indicate the number of fasteners  250  remaining in device  100 . The display element can be provided by a mechanically changing numeral (e.g., such as an odometer-style display wheel) or by an electronic display, such as an LCD, LED, or similar device. The displayed element can be a numeral, some other indicator (e.g., changing color, countdown needle, etc.), or a combination thereof. A color changing display offers a benefit of always being positioned at the same spot on the device, not requiring the surgeon to change viewing angle, and also is language-neutral. The display element can be fed by information from marker element  947 . For example, a series of electrical contact points can be disposed within feeder cover  941  (see  FIG. 5 ), and marker element  947  can provide an electrical contact point that completes a circuit with one of the points within cover  941 , such that the completed circuit indicates a number of fasteners  250  in device  100 . A display suitable for modification for use with the invention is described in U.S. Pat. No. 8,132,705 to Viola, the contents of which are incorporated by reference. Device  100  will generally deliver one or a plurality of fasteners  250  to a surgical site through the operation of a mechanical structures of handle  102  and shaft  103 . 
         [0036]      FIG. 3  shows components of a handle of a fastening device. As can be seen in  FIG. 3 , one or more of push rod  135  are linked to one or more of translator bar  131 . Translator bar  131  has a pin  127  fixed into a slot  123  of slot wheel  115 . As shown in  FIG. 3 , applicator  100  includes a second slot wheel  119 . Additional slot wheels may be included. The rotation of the slot wheel is driven through gear mechanism  111  by a geared face  107  of trigger  105 . 
         [0037]    By the relationship of these parts, when trigger  105  is squeezed, each of the slot wheels rotate. Because each slot (e.g., slot  123 ) is irregularly shaped (e.g., not a circle concentric with slot wheel  115 ), the corresponding translator bar translates independently relative to handle  102  and with acceleration defined by the disposition of the slot. The independent translation of translator bar  131  causes the independent translation of push rod  135  which (with reference to  FIG. 7 ) cause the independent action of hook insertion needle  352  and loop insertion needle  357 , as described above. 
         [0038]    Embodiments of the invention provide methods of hernia mesh fixation that include using device  100 , which includes indicator  141  on shaft  103  to show a number of fasteners that remain. Preferably, each operation of the trigger delivers and releases one fastener (e.g., closing it into a closed loop within the target tissue) and decrements the number shown by the indicator (e.g., by a color change or by repositioning the slider). Methods of the invention include viewing the surgical site via a scope while also viewing the indicator via the scope. Methods include replacing a cartridge with a full cartridge and not taking any additional steps to reset indicator  141 . That is, since indicator  141  is on the cartridge and in linkage with fastener stack  955  (see, e.g.,  FIG. 4 ), indicator  141  will be default indicate a number of fasteners and not require intervention or a manual change. Additionally, methods of the invention allow for hernia mesh fixation and other procedure with greater dexterity and greater control over orientation of fasteners  250  in space and in tissue. Since a surgeon can see a number of fasteners remaining while applying a fastener, the surgeon can make an informed decision about where the next fastener should go. Surgical procedure like mesh fixation are complex. It occurs that a surgeon must position the mesh or target tissue using the tip of the device and then hold the mesh or tissue in place while applying the next one, two, or three fasteners. To be done properly, a surgeon preferably does not take his eyes off of the target site. Not knowing a number of fasteners that are ready to fire can compromise the deftness of the application. 
         [0039]    In certain embodiments, the series of coordinated motions of the insertion needles, and the delivery of a fastener  250 , is operated and coordinated electronically. For example, applicator device  100  can include servomotors operably connected to a governing circuit, chip, or combination thereof. A motor can drive the slot wheels. Or, motors can drive each push rod as governed by a chip executing instructions provided, for example, by a tangible, non-transitory computer memory such as, for example, a field-programmable gate array or a disc drive. 
         [0040]    Where shaft  103  includes an articulation joint, articulation knob  106  controls the flexure of the joint. Knob  106  is rotated by a user (e.g., with a thumb). During the rotation, an articulation cable is wrapped around the knob&#39;s axis, pulling it toward the handle, articulating the joint. Knob  106  can include one or more of socket  139  adapted to fit a ball plunger in place once a desired degree of articulation is obtained. 
         [0041]      FIG. 4  shows a cutaway view of applicator section  101  and fastener feeder mechanism  919 . In operation, a comb driver assembly  951  first generates a single up and down stroke of a drive comb at the end of each application cycle (discussed and shown in more detail in connection with  FIGS. 12-16  below). In  FIG. 4 , the drive comb extends under the plurality of fasteners  250 , i.e., fastener stack  955 . As a response to the stroke, the entire fastener stack  955  is pushed forward by the drive comb. During this process a hold comb (not shown in  FIG. 4 , see  FIG. 5 ) prevents a downward movement of the pre-formed fasteners  250  in fastener stack  955 . 
         [0042]    In some embodiments, each time that a fastener is delivered, fastener support slide  953  advances by a fixed distance. Accordingly, in such embodiments, a position of fastener support slide within feeder mechanism  919  and thus shaft  103  is reflective of a number of fasteners remaining in device  100  to be delivered. The possible positions of fastener support slide  953  within shaft  103  may thus be quantized by a mechanical linkage relating the position of fastener support slide  953  to a number fasteners  250  remaining in fastener stack  955 . In this way, a position of marker element  947  corresponds to a number of fasteners remaining in device  101 . 
         [0043]    Once the fasteners stack  955  is pushed upward (e.g., forward), the last fastener  250  is spread by the fastener spreader  961  and is positioned at collection slots  963  and  964  (visible in  FIG. 5 ), ready to be collected by the insertion needles  352  and  357  (see  FIG. 7 ) during the next application cycle. Each fastener  250  supports the next fastener  250  and prevents the lateral movement of its middle while it is pushed by drive comb  957 . The last fastener  250  is supported by the fastener support slide  953 . Fastener support slide  953  is pushed by the drive comb  957  together with the fasteners. A marker element  947  may protrude to the outer surface of the shaft, through a slot in feeder covers  941  (shown in  FIG. 5 ), to indicate provide an indicator of a number of fasteners remaining in the device. 
         [0044]      FIG. 5  gives an exploded view of the fastener feeder mechanism  919 . A hook insertion needle  352  lies under front feeder cover  941 , which includes marker slot  943 . Front cover  941  covers hold comb  945 . Fastener stack  955  includes a plurality of fastener  250  extending from fastener support slide  953 , which also includes marker element  947 . Front cover  941  and back cover  959  covering and holding the fastener stack  955  and the fastener support  953 , said front and back cover can be at least partially, substantially, or entirely encapsulated within the shaft cover  949  and terminate at shaft cap  939 . Comb driver assembly  951  with comb driver hook  948  operates drive comb  957 , as described below. Fastener feeder mechanism  919  includes loop insertion needle  357  disposed near fastener spreader  961 . Shaft cap  939  includes a loop collection slot  963  and a hook collection slot  964 . Fastener feeder mechanism  919  functions to deliver one fastener  250  from fastener stack  955  per operation of device  100 . 
         [0045]      FIG. 6  shows a fastener  250  according to certain embodiments. Preferably, fastener  250  is pre-formed and may have substantially the shape shown in  FIG. 6 . Generally, fastener  250  may include an extended body  251  having a first end  252  and a second end  253 . First end  252  may include an opening  265  configured to capture and retain second end  253 .  FIG. 6  shows pre-formed fastener  150  in an open configuration, while  FIG. 10  shows fastener  250  in a closed configuration.  FIG. 11  shows fastener  250  in a locked configuration. Fastener  250  includes insertion slope  277  and at least one barb  269  that are dimensioned to operate with hook insertion needle  352  and loop insertion needle  357  of the applicator section  101  shown in  FIG. 7 . 
         [0046]      FIG. 7  shows applicator section  101 . Applicator section  101  provides loop insertion needle  357  and hook insertion needle  352 . Loop insertion needle  357  may be disposed within a needle jacket  358 . Discussed in more detail below, the function of needle jacket  358  may be to hold a portion of loop insertion needle  357  in a substantially straight configuration, while a portion of loop insertion needle  357  distal to the straight portion exhibits a curved configuration. Hook insertion needle  352  may include one or more catch slot  937  to catch or hold a portion of a fastener  250 , such as barb  269  on second end  253 . 
         [0047]      FIG. 8  shows an applicator section of a fastening device with fastener  250  according to certain embodiments.  FIG. 7  shows the applicator section of  FIG. 8 , without a fastener  250 .  FIG. 7  shows loop insertion needle  357  and hook insertion needle  352 . As shown in  FIG. 8 , the needle integration section  935  is shaped as a continuation of the needle tip in order to a allow penetration through the mesh and the tissue layers. Specifically, fastener  250  includes insertion slope  277  and the applicator includes a sloped needle integration section  935  that are dimensioned to cooperate to provide a substantially smooth, continual slope. Bulges  931  prevent the mesh fibers and the tissue from being caught between fastener  250  and hook insertion needle  352 . As shown in  FIG. 7 , catch slot  937  is operable to hold the hook side of fastener  250  in place during penetration, e.g., by engaging barbs  269 . 
         [0048]      FIGS. 9-11  depict the operation of applicator section  101  of the applicator section depicted in  FIG. 8 .  FIG. 9  shows an initial stage of operation. Hook insertion needle  352  and loop insertion needle  357  are fully engaged with first member  253  and second member  252 , respectively, of fastener  250 . Upon each operation of trigger  105 , hook insertion needle  352  extends from a terminal end of shaft  103 , as does loop insertion needle  357 . Needle jacket  358  also extends from the terminal end. As shown in  FIG. 9 , the function of needle jacket  358  may be to hold a portion of loop insertion needle  357  in a substantially straight configuration, while a portion of loop insertion needle  357  distal to the straight portion exhibits a curved configuration. This allows fastener  250  to penetrate to a depth that is not otherwise limited by the geometry of device  100 . Some prior devices can fasten deeper only by holding a fastener within a larger shaft or only by unspooling threaded suture material. Here, first end  252  and a second end  253  of fastener  250  may be any desired length and the action of hook insertion needle  352 , loop insertion needle  357 , and needle jacket  358  operate to fasten fastener  250  with tissue and release it there at a desired and variable depth. 
         [0049]    As seen in  FIG. 10 , the loop is fully deployed and the hook partially penetrates the loop. In  FIG. 11 , hook insertion needle  352  holds the loop in place while the loop insertion needle  357  is retracted. 
         [0050]      FIGS. 10-11C  show locking and release of fastener  250 .  FIG. 9A  shows hook insertion needle  352  pushing the hook through the loop. As shown in  FIG. 10 , since the hook is slightly wider than the loop&#39;s wide section, first member  253  is caught in second member  252  and removed from the hook insertion needle  352  once hook insertion needle  352  is retracted.  FIG. 11  shows that, once tension is applied on the fastener, the hook slides to the narrow section of the hook. In this stage the fastener is locked. 
         [0051]    As shown in  FIGS. 9-11 , delivering and fastening a fastener  250  may involve extending one or both ends of fastener  250  a distance from a terminal end of applicator section  101  along a path that includes both a straight portion and a curved portion. When a practitioner depresses trigger  105 , loop insertion needle  357  extends from insertion tube  356  and interacts with first member  253  via loop interface hook  261 . Hook insertion needle  352  has and maintains a substantially straight conformation as it assists in driving a hook end of fastener  250  into tissue. When loop insertion needle  357  is extended out from applicator section  101 , it curves to guide the fastening of the fastener. 
         [0052]    Fastener  250  is delivered by pushing each of its ends into tissue. Delivery is coordinated by the independent translation of push rods operably coupled to hook insertion needle  252  and loop insertion needle  357 , which is triggered through the use of trigger  105 . Coordination of delivery involves extending hook end of fastener  250  away from applicator section  101  while also extending loop end of fastener  250  and bringing the two ends of the fastener together (e.g., through the operation of a shape memory material in loop insertion needle  357 ). Methods include using the needles to drive fastener  250  into tissue and retracting the needles so they disengage from fastener  250  leaving it in place and fastened in a closed loop. 
         [0053]    The invention thus provides methods for securing a medical prosthesis to tissue. Securing the prosthesis is accomplished through delivering a fastener to a target tissue that has a prosthesis applied to it, using applicator  100 . Methods include inserting a distal portion of fastening device  100  into a patient&#39;s abdominal cavity through a trocar or through an incision. The distal end is pressed against the hernia mesh and a fastener is delivered through the tissue and hernia mesh and secured in place by pressing trigger  105  on handle  102 . Shaft  103  is then removed. 
         [0054]    Delivery according to the methods of the invention causes the first end of the body to mate with and be retained by the second end of the body, thereby forming the fastener into a closed configuration and securing the prosthesis to the tissue. The prosthesis can be secured by employing a fastening structure provided by the first and second members of fastener  250 . 
         [0055]    For hernia mesh  400  fixation, it is preferable that fastener  250  should be anchored to a fascia layer  401 . Fascia is a layer of fibrous tissue containing closely packed bundles of collagen. Fascia provides a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves. This is the layer to which surgeons affix a hernia mesh and the fastener design should form a strong anchor to that layer. 
         [0056]    In each patient the thickness of the pre-peritoneal fat layer is different. For example, the first fascia layer in obese patients is significantly deeper than in slim patients. Some existing fixed-length hernia tacks favor shorter lengths so that, in slim patients, they will not penetrate all the way through the abdominal wall and to the skin. Fasteners that are too small, however, will not anchor into the fascia  401  in some sites or in obese patients for whom the pre-peritoneal fat layer is substantially thick. A fastening device of the invention is provided that can fix a hernia mesh despite variations in tissue with fasteners that pass beyond the hernia mesh by a controlled amount (e.g., between about 3 millimeters and 15 millimeters). By provided fasteners that extend only about a couple of millimeters past the hernia mesh, a fastening device of the invention provides good fixation to prevent recurrence of the hernia. By avoiding use of a fastener that is too long, post-operative pain is minimized. Considerations in fastener operation are discussed in Abhishek, et al., 2012, Laparoscopic Umbilical Hernia Repair: Technique Paper, ISRN Minimally Invasive Surgery, pp. 1-4, Article ID 906405, and in Nguyen, et al., 2008, Postoperative Pain After Laparoscopic Ventral Hernia Repair: a Prospective Comparison of Clips Versus Tacks, JSLS 12:113-116, the contents of each of which are incorporated by reference. 
         [0057]      FIGS. 12-16  depict the operation of the comb driver mechanism of fastener feeder mechanism  919 . As seen in  FIG. 12 , comb driver assembly  951  provides a connection between comb driver hook  948  plus comb driver slide  975  and drive comb  957 . Comb driver assembly  951 , fastener support slide  953 , or fastener stack  955  preferably has, somewhere thereon, marker element  947 . Any suitable structure or element can be used for marker element  947 . For example, marker element  947  may comprise a pin that engages part of an indicator  141 . Marker element  947  may include an electrical contact point. In some embodiments, marker element  947  is itself a visible portion that is visible from an outside of shaft  103  and is viewed by a surgeon during a procedure. In certain embodiments, marker element  947  is one of fastener  250  (e.g., the last one, or most proximal one of fastener  250 ). As shown in  FIGS. 12-16 , marker element  947  will track the progress of drive comb  957  or a portion of the mechanics of the delivery mechanism during delivery. During delivery, release slope  977  and release bulge  976  release the comb driver hook from the hook insertion needle. Comb driver spring  981  can be seen by hook slot  983 . The comb driver hook  948  is connected to the comb driver slide  975  by a flexible pin, allowing its rotation.  FIG. 14  depicts a pulling back stage. At the final stage of the application cycle, the hook insertion needle  352  moves back while pulling the back the comb driver slide  975  and the drive comb  957  while pressing the comb driver spring  981 . During this movement the comb teeth are engaged with pre-formed fasteners  250 .  FIG. 15  shows release. Once the release bulge  976  reaches the release slope  977 , release bulge  976  is pushed laterally and removes the hook  948  out of the hook slot  983 .  FIG. 16  shows advancement of fastener  250 . The compressed spring  981  pushes the comb driver  951  and the drive comb  957  forward while advancing the entire fastener stack  955 . 
         [0058]    In  FIGS. 1-16 , each fastener  250  is depicted as a pre-formed self-locking fastener, although other embodiments discussed herein are within the scope of the invention. For example, indicator  141  may be used with anchor-style fasteners  250 , stretchable fasteners, staples, helical fasteners, or others. 
         [0059]      FIG. 17  shows an applicator section  101  of fastening device  100  having a cartridge  151  for delivering a plurality of fastener  250  having an anchor style. Cartridge  151  has anchor-style fastener  250  of a long size disposed therein. Cartridge  151  can also accept anchor-style fasteners  250  of short or intermediate sizes, each separately or in any combination. Each operation of trigger  105  causes hammer  619  to travel a long-fastener hammer travel distance (LHTD). Marker element  947  may be disposed within the delivery mechanism on, for example, a proximal-most anchor. When delivering an anchor-style fastener  250  of a long size, hammer  619  will travel a long-fastener internal travel distance (LITD). As described in co-pending U.S. patent application Ser. No. 13/768,726 to Levy, et al., filed Feb. 15, 2013, and incorporated by reference in its entirety, anchor-style fasteners  250  of a variety of different size and even of mixed sizes may be delivered by the depicted mechanism. The anchor-style fasteners  250  are inserted into the tissue by pushing them forward using a reciprocal moving hammer  619 . Hammer  619  scoops only the first anchor style fastener  250 . An additional mechanism such as a spring positions each new fastener  250  in front of the hammer  619 . 
         [0060]      FIG. 18  illustrates a device  100  for delivering a plurality of stretchable fastener  250 . Stretchable fastener  250  generally includes an elastic material such as, for example, a poly-urethane, silicon, polyester, polyamide (e.g., nylon), polyolefin (e.g., polyethylene or polypropylene), poly-urethane carbonate, polydioxane, animal gut such as chromated catgut, metal such as steel, tantalum, or a shape memory metal. Marker element  947  may be disposed on or at a base of proximal-most fastener  250 . Fastener  250  may include jacketed filaments such as twisted polyamide. This allows a surgeon to set the penetration depth of each individual stretchable fastener  250  at handle  102  without removing applicator section  101  from a patient. Once deeper penetration is set, the fastener tip  629  penetrates more into the tissue. Since the stretchable fastener  250  can be stretched, the final result is deeper penetration and longer stretchable fastener  250 . As shown in  FIG. 18 , once the device is configured to penetrate deeper and a stretchable fastener  250  is delivered to tissue, the central core  625  of the stretchable fastener  250  is stretched to a deployed core length (DCL). 
         [0061]      FIG. 19  shows applicator section  101  with cartridge  151  loaded with tack-style fasteners  250  of a plurality of sizes. A marker element  947  may be disposed on or near the delivery mechanics such as, for example, on or near a base of proximal-most tack-style fastener  250 . As shown in  FIG. 19 , at least two types of fastener  250  are arranged inside the device, e.g. the first three of fastener  250  are long of fastener  250  and rest are shorter. This allow the surgeon to apply different sized of fastener  250  without replacing a cartridge  151 . If the surgeon doesn&#39;t want to apply any of a long fastener  250 , each of the long fastener  250  can be ejected outside of the patient body before fastener  250  application. As before, the plurality of fastener  250  are arranged such that no adjustment at handle  102  mechanism is required. The base-to-base length (BTBL) between the base of each fastener is constant along a length of cartridge  151  regardless of a size of tack-style fasteners  250 . For any version of a cartridge  151 , the delivery mechanism displaces a fixed distance in a lateral direction along shaft  103 . In a similar way to the anchor-style fastener  250  cartridge  151 , the difference between the versions is the length in which the fastener  250  is moving inside and outside the device. Helical tack-style fasteners that may be adapted for use with device  100  are discussed in U.S. Pat. No. 8,282,670; U.S. Pat. No. 8,216,272; and U.S. Pat. No. 8,114,099, the contents of which are incorporated by reference. In some embodiments, a fastener may have tapered portions of a shaft, such as those shown in U.S. Pub. 2004/0098045. 
         [0062]    As used herein, the word “or” means “and or or”, sometimes seen or referred to as “and/or”, unless indicated otherwise. 
       INCORPORATION BY REFERENCE 
       [0063]    References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. 
       EQUIVALENTS 
       [0064]    Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.