Abstract:
A device for the repair of tissue and methods of use and manufacturing thereof are described herein. Applications for the use of the device include, e.g., repair of atrial septal defects (ASD), patent foramen ovale (PFO), left atrial appendage closure and stent graft fixation among other applications throughout the anatomy. The implant portion of the device is available in a variety of sizes and configurations to accommodate the vast complexity of the target anatomy.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/296,868, filed on Jan. 20, 2010, which is expressly incorporated herein in its entirety by reference thereto. 
         [0002]    Further, each of the following is hereby incorporated in its entirety by reference thereto: U.S. patent application Ser. No. ______, Attorney Docket No. 14895/4, filed on Jan. 20, 2011, U.S. patent application Ser. No. ______, Attorney Docket No. 14895/5, filed on Jan. 20, 2011; and U.S. patent application Ser. No. ______, Attorney Docket No. 14895/6, filed on Jan. 20, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0003]    The present invention relates to a tissue repair implant and delivery device and method. 
       BACKGROUND INFORMATION 
       [0004]    Some surgical interventions require the repair of tissue, e.g., closure of the tissue or graft fixation. These procedures may include, for example, treatment of atrial septal defects (ASD), patent foramen ovale (PFO), left atrial appendage closure, stent graft fixation, and hernia repair, among others. 
         [0005]    ASDs and PFOs are considered to be two of the leading contributors to embolic stroke. Stroke is the third leading cause of death in the United States and one of the leading causes of adult disability. It is estimated that 80% of strokes are preventable and that repair of existing ASDs and PFOs will reduce the incidence. When ASDs and PFOs are present in the heart, a debilitating condition may occur. Deoxygenated blood may pass from the right atrium through either the ASD and/or PFO into the oxygenated blood of the left atrium. It has been estimated that approximately one in four individuals in the general population have a PFO. Individuals who have unknown causes of stroke (cryptogenic stroke), have a 40 percent increase in the likelihood of a PFO being present. PFO is even more prevalent in individuals who have had strokes under that age of 55. 
         [0006]    U.S. Pat. No. 7,220,265 describes a device for closure of PFO, wherein a catheter is directed into proximity of the PFO. The catheter is inserted between the septum primum and the septum secundum into the left atrium. The catheter then deploys a first closure member, e.g., a “grappling hook element,” in the left atrium. The catheter is then drawn back into the right atrium where a second closure member, e.g., a second grappling hook element, is deployed. The first and second closure members are connected by a central connecting member such that the septal tissues are compressed together between the two opposed closure members. U.S. Pat. No. 7,220,265 also discloses a method of closing the PFO using sutures, whereby implantable anchors purportedly limit the need for a continuous thread. The devices and methods of U.S. Pat. No. 7,220,265 require maneuvering of a medical device, e.g., a catheter or suture needle, in both the right and left atria. This may present substantial complexity and difficulty to the procedure, possibly increasing the likelihood of surgeon error and/or increasing the time required to complete the procedure. 
         [0007]    Further, typical existing anchors are configured to joining soft tissue to hard tissue, since there is no way to take out the slack with soft tissue to soft tissue joining. 
         [0008]    Thus, there is a need for a closure mechanism and method that is simple to operate and only requires access to one side of the tissue or tissues. Further, there is a need for a reliable closure that may be precisely located. 
         [0009]    Moreover, some tissue defects, e.g., some heart defects and inguinal hernias, require the implantation of a mesh. In the example of an inguinal hernia, the mesh is intended to create a barrier against abdominal cavity contents protruding through a defect the abdominal peritoneum and inguinal canal. A known treatment for such hernias involves applying a single anchor to a mesh, e.g., a square mesh, then pulling the mesh taut and applying a second anchor to the mesh. This sequential fastening and tightening is repeated until the mesh is secured over the defect. This method is procedurally costly and time consuming, however, and there is a risk that the mesh may not be properly or sufficiently tautened, which could render the mesh ineffective in preventing the protrusion of the abdominal cavity contents through the inguinal canal. 
         [0010]    Thus, there is also need for an implanting mechanism and method that allows for a quick and reliable securement of a mesh to repair a tissue defect, e.g., allowing for simultaneous application of fasteners. 
         [0011]    Further, there is a need for a mechanism and method that reduces procedural costs and allows access to difficult-to-reach locations of the anatomy. 
       SUMMARY 
       [0012]    According to example embodiments of the present invention, a device for the repair of tissue and methods of use and manufacturing of the device are provided. Applications for the use of the device include, e.g., repair of atrial septal defects (ASD), patent foramen ovale (PFO), left atrial appendage closure, stent graft fixation, and hernia repair, among other applications throughout the anatomy. The implant portion of the device may be provided in a variety of sizes and configurations to accommodate the vast complexity of the target anatomy. 
         [0013]    Example embodiments of the present invention provide for an implant and a delivery device which may be used to bring adjacent tissues into approximation in order to provide a wide array of therapeutic treatments, including, e.g., repair of ASD, PFO, left atrial appendage occlusion, and stent graft fixation among many other applications in the human body, or, e.g., any suitable mammalian body. 
         [0014]    According to example embodiments of the present invention, a fastener having a distal end and a proximal end includes an elongated body having a distal tip, and anchoring filaments extending radially outwardly from the elongated body in a proximal direction of the elongated body, the anchoring filaments configured to resist proximal movement of the elongated body when the fastener is driven in a distal direction into one or more layers of tissue. 
         [0015]    The fastener may also have a proximal head disposed proximally from the anchoring filaments, wherein the proximal head extends radially outwardly from the elongated body and is configured to limit the depth to which the fastener is proximally driven into one or more layers of tissue. 
         [0016]    The proximal head may be fixed to the elongated body. 
         [0017]    The proximal head and the elongated body may be formed together as a single monolithic piece. 
         [0018]    The fastener may further include a proximal head configured to engage a proximal portion of the elongated body. 
         [0019]    The proximal head may include threads that engage corresponding threads on the proximal portion of the elongated body when the proximal head engages the proximal portion of the elongated body, wherein rotation of the proximal head with respect to the threads of the proximal portion of the elongated body causes movement of the proximal head along the longitudinal axis of the elongated body. 
         [0020]    The proximal head and the elongated body together form a ratchet when the proximal head engages the proximal portion of the elongated body, wherein the proximal head is moveable distally along the elongated body and restrained from proximal movement along the elongated body. 
         [0021]    The fastener may be formed partially or entirely of, e.g., a bio-absorbable material. 
         [0022]    The distal tip may be tapered. The distal tip may be blunt or taper to a sharp point. The distal tip may be a cutting tip. The distal tip may include at least one concave tapered cutting edge. The distal tip may include three concave tapered cutting edges. The three concave tapered cutting edges may be equidistant from each other around a circumference of the fastener. The distal tip may be a reverse-cutting tip. 
         [0023]    According to example embodiments of the present invention, a surgical device for implanting a fastener having proximally directed anchoring filaments includes a device body and a fastener driver coupled to the device body and configured to penetrate a first soft tissue, engaging an unsupported second soft tissue, and anchoring the fastener in the second soft tissue so that the fastener can bring the second soft tissue in direct apposition to the first soft tissue. 
         [0024]    The fasteners are preferably driven at a speed greater than 50 meters per second, more preferably in a range of 50 to 350 meters per second, and most preferably at 350 meters per second. However, it should be understood that the fasteners may be driven at any suitable speed sufficient for the fasteners to puncture tissue. 
         [0025]    The fastener driver may be configured to drive the fastener at a predetermined distance and velocity based on a determined distance between the first tissue and the second tissue. The fastener driver is adjustable to drive the fastener at different distances and velocities based on the determined distances between the first tissue and the second tissue. The fastener driver may be configured to impart a momentum to the fastener sufficient to drive the fastener through the first soft tissue and into the second soft tissue. The fastener driver may be configured to transfer hydraulic force to the fastener to impart the momentum. Saline may be provided for the hydraulic propulsion. 
         [0026]    The surgical device may further include the fastener, wherein the anchoring filaments of the fastener are configured to resist proximal movement of the fastener when the fastener is driven through the first soft tissue and into the second soft tissue. 
         [0027]    The fastener may include a proximal head and the fastener driver includes a plurality of flanges configured to contact a distal face of the proximal head to limit the depth to which the fastener is driven by the fastener driver. 
         [0028]    The flanges may be radially expandable from each other to release the proximal head of the fastener. 
         [0029]    The fastener may be attached to a suture. 
         [0030]    According to example embodiments of the present invention, a surgical device comprises a fastener including an elongated body having a proximal end and a distal tip, and a filament secured to the fastener and extending from the proximal end of the elongated body. 
         [0031]    The filament may be a braided filament. 
         [0032]    The device may be formed by coextrusion of the fastener over the filament. 
         [0033]    The fastener may further include anchoring filaments proximally extending from the elongated body, the anchoring filaments configured to resist proximal movement of the elongated body when the fastener is driven in a distal direction into one or more layers of tissue. The fastener and the filament may be comprised of a bio-absorbable material. 
         [0034]    The distal tip of the fastener may be blunt. The distal tip of the fastener may taper to a sharp point. The distal tip may be tapered. The distal tip may be a cutting tip. The distal tip may include at least one concave tapered cutting edge. The distal tip may include three concave tapered cutting edges. The three concave tapered cutting edges may be equidistant from each other around a circumference of the fastener. 
         [0035]    The distal tip may be a reverse-cutting tip. 
         [0036]    According to example embodiments of the present invention, a surgical device comprises a fastener including a proximal end and a distal tip, the fastener configured to anchor into a tissue when distally driven into the tissue, a filament secured to the fastener and extending from the proximal end of the elongated body, and a fastener driver coupled to the device body and configured to distally drive the fastener into the tissue. 
         [0037]    The filament may be a braided filament. 
         [0038]    The distance to which the fastener is driven may be limited by a predetermined amount of slack in the filament prior to the driving, the distance being limited by the tautening of the filament. 
         [0039]    The fastener may include proximally extending anchoring filaments configured to anchor the fastener into the tissue. The fastener driver may be configured to drive the fastener into through a first tissue and into a second tissue such that the fastener anchors in the second tissue. The first and second tissues may be soft tissues, the fastener driver being configured to impart a momentum to the fastener sufficient to drive the fastener through the first soft tissue and into the second soft tissue when the second soft tissue is unsupported. The fastener driver may be configured to drive the fastener at a predetermined distance and velocity based on a determined distance between the first tissue and the second tissue. The fastener driver may be adjustable to drive the fastener at different distances and velocities based on the determined distances between the first tissue and the second tissue. The fastener driver may be configured to drive the fastener using a hydraulic propulsion. Saline may be provided for the hydraulic propulsion. 
         [0040]    The surgical device may further comprise a capstan configured to proximally reel the filament after the fastener has been driven by the fastener driver. 
         [0041]    The proximal reeling of the filament may cause a corresponding proximal movement of the tissue when the fastener is anchored in the tissue. 
         [0042]    The fastener may be molded to the filament. The fastener may be coextruded with the filament. The filament may be a braided filament. The fastener may include a plurality of molded radially disposed anchoring filaments. 
         [0043]    According to example embodiments of the present invention, a surgical device comprises an elongated fastener body, and wings disposed on a distal portion of the fastener body, wherein the body has external corrugations and the wings have external corrugations. 
         [0044]    According to example embodiments of the present invention, a method of purposefully bringing two adjacent tissues together includes, the placement of a delivery system device in approximation of the tissue, creating surface tension with the device, and ejecting an absorbable or non-absorbable implant from the device. The device controls the exact placement of the implant, which penetrates both tissues thus creating contact between the two tissue surfaces so that the two tissues are in approximation. 
         [0045]    According to example embodiments of the present invention, an absorbable or non-absorbable implant has a needle-like tip tapering to a body portion that contains filaments protruded therefrom, the filaments present over a percentage of the length of the body. The implant may transition from the portion with filaments to a threaded section for, e.g., the remaining percentage of the length of the body. The threaded section is capable of receiving a nut and/or head which can move independently from the body of the implant. The head is able to be independently rotated so that the head can compress the two previously penetrated adjacent tissues to bring them into apposition. 
         [0046]    According to example embodiments of the present invention, a device includes a housing and a firing pin disposed in the housing and axially movable in the housing. The device also includes a spring coupled to the housing and the firing pin to apply a spring force between the housing the firing pin. The housing includes a distal portion configured to receive an implant. The device includes at least one of a cable and a shaft, the at least one of a cable and shaft being configured to releasably attach to a proximal end of the firing pin and to pull the firing pin to a proximal position, thereby increasing a force exerted between the spring and the housing. The at least one of a cable and a shaft is configured to release the firing pin from the proximal position to allow the firing pin to move distally forward in response to the spring force. The distal motion of the firing pin causes the firing pin to extend into the distal portion of the housing. 
         [0047]    The device may include two or more implants in an end-to-end arrangement. 
         [0048]    The device may be configured to cause only the distal-most of the two or more implants to be ejected when the firing pin extends into the distal portion after being released by the at least one of a cable and a shaft. 
         [0049]    The device may include a sleeve disposed in the housing, the sleeve configured to move the firing pin and spring to a second, more distal location within the housing in order to drive the next of the two or more implants. 
         [0050]    According to example embodiments of the present invention, an implant driving device includes a housing and a driving shaft disposed in the housing and axially movable and rotatable in the housing. The housing includes a distal portion that houses two or more implants in an end-to-end arrangement, the two or more implants being drivable by the axial movement and rotation of the driving shaft. 
         [0051]    The proximal-most of the two or more implants may have a recess that mates with a corresponding projection of the driving shaft. 
         [0052]    Each of the two or more fasteners may have distal end portions having a geometry that mates with a proximal recess of each of the other of the two or more fasteners. 
         [0053]    Two or more, e.g., all, of the fasteners may be driven simultaneously, or substantially simultaneously. 
         [0054]    The fasteners may be driven in a plurality of sets, each set of anchors being driven simultaneously, or substantially simultaneously. 
         [0055]    Further features and aspects of example embodiments of the present invention are described in more detail below with reference to the appended Figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0056]      FIG. 1  is an illustration of two surgical implants. 
           [0057]      FIGS. 2A and 2B  are schematic illustrations of surgical implants with driving mechanisms. 
           [0058]      FIG. 3  is a schematic illustration of a surgical implant with a driving mechanism. 
           [0059]      FIG. 4  is an illustration of a surgical implant. 
           [0060]      FIG. 5A  is an illustration of a surgical implant. 
           [0061]      FIG. 5B  is a cross-sectional view of the surgical implant of  FIG. 5A . 
           [0062]      FIGS. 6A to 6C  schematically and sequentially illustrate the bringing into apposition of two tissues using a surgical implant. 
           [0063]      FIG. 7  is an illustration of a surgical implant. 
           [0064]      FIG. 8  is an illustration of a distal end portion of a surgical implant. 
       
    
    
     DETAILED DESCRIPTION 
       [0065]      FIG. 1  is an illustration of two surgical micro implants or fasteners  100  and  200 . The surgical implants  100  and  200 , which may be absorbable or non-absorbable, are designed to penetrate and join two adjacent viscera or tissue planes. The implants  100  and  200  are designed to pass through the first tissue and the second tissue under controlled rapid deployment. The implant is shaped similarly to a needle with a predetermined geometry. Each implant  100 ,  200  has an elongated body  105 ,  205  that tapers in a distal region to a needle-like tip  110 ,  210 . Each implant  100 ,  200  may be deployed, as described in greater detail below, by being pushed from a precisely placed hollow needle or tube containing the implant  100 ,  200 . The implants disclosed herein may be formed using e.g., micromachining techniques. 
         [0066]    The micro implants  100  and  200 , as well as any other implants disclosed herein may have a diameter of one millimeter, or approximately one millimeter, and a length that is in a range from 5 millimeters to 10 millimeters. According to some example embodiments, the diameter is less than one millimeter. According to some example embodiments, the diameter is in a range from 0.8 millimeters to 1.2 millimeters. It should be understood, however, that other dimensions may be provided. 
         [0067]    The body  105 ,  205  of each implant  100 ,  200  has specifically designed micro anchoring filaments  115 ,  215  which arise from a core  120 ,  220  of the implant  100 ,  200  to extend outwardly from the core  120 ,  220 . The anchoring filaments  115 ,  215  are located around the circumference and along at least a portion of the length of the body  105 ,  205  of the implant  100 ,  200 . This allows the implant to resist removal once it has penetrated the tissue. 
         [0068]    The filaments  115 ,  215 , or any other filaments described herein may have any suitable dimensions. For example, it may be advantageous to provide a filament tip (i.e., free end) diameter of 0.1 millimeters and tapering toward a diameter of 0.25 millimeters at the body. 
         [0069]    The core  120 ,  220  has a constant diameter along a substantial length of the body  105 ,  205  of the implant  100 ,  200 . For example, the core  120  of the implant  100  has a constant cross-section, and constant diameter, from a head portion  125  to a substantially conically shaped tapered portion toward the tip  110 . It should be understood however, that the implants  100  and  200  may have a more continuous taper and/or have a constant or non-constant rate of taper. 
         [0070]    The anchoring filaments  115 ,  215  extend outwardly at an angle with respect to the longitudinal axis of the implant  100 ,  200 . In this regard, the filaments, in addition to extending outwardly away from the longitudinal axis, also extend in a proximal direction, away from the tip  110 ,  210 . This allows for the filaments  115 ,  215  to slide along the pierced tissue during distal driving or insertion. However, proximal movement of the implants  100 ,  200  from the inserted position is prevented or resisted by engagement of the outer, free ends of the filaments  115 ,  215  with the relatively soft tissue. The filaments  115 ,  215  may be flexible or substantially rigid. The filaments  115 ,  215  should, however, have sufficient stiffness or strength to resist proximal withdrawal of the implant  100 ,  200  from the inserted position. Further, although the filaments  115 ,  215  are illustrated as being straight, it should be understood that some or all of the filaments  115 ,  215  may be at least partially curved, and/or have one or more bends between straight portions and/or curved portions. Moreover, the filaments  115 ,  215  of a given implant  100 ,  200  may have constant or differing lengths, radial extensions, and/or angles with respect to the longitudinal axis of the implant  100 ,  200 . 
         [0071]    The filaments  115 ,  215 , or any other anchoring filaments described herein may be provided with any appropriate density and relative spacing, depending on the particular application. For a given application, a greater density (i.e., a greater number of filaments per unit of surface area) of smaller filaments may be provided, or a lesser density of larger filaments (optionally reinforced with a shape memory alloy, e.g., nitinol and/or spring-loaded steel), while presenting the same or comparable suture retention or “pull through strength.” The optional reinforcement could be a “V” shaped portion formed of shape memory alloy, e.g, nitinol and/or spring-loaded steel. The filaments  115 ,  215  may be absorbable or non-absorbable in whole or in part. 
         [0072]    Each implant  100 ,  200  includes a proximal head  125 ,  225 . The head  125 ,  225  extends radially beyond the core  120 ,  220  and has a larger axial cross section than the core  120 ,  220 . The head  125 ,  225  may prevent the implant  100  from being driven too deeply into, or entirely through, the tissue. As the implant  100 ,  200  is driven distally along its longitudinal axis, the core  120 ,  220  pierces into and progresses through the tissue. The head  125 ,  225 , having a larger diameter or cross section, prevents or resists the proximal portion of the implant  100 ,  200  from extending into the tissue. Thus, where two layers of tissue are pierced and joined, the distal layer of tissue is constrained against distal movement away from the proximal layer of tissue by engagement of the distal layer with the filaments  115 ,  215 , and the proximal layer is constrained against proximal movement away from the distal layer by engagement of the proximal layer (e.g., the outer proximal surface of the proximal layer) with the head  125 ,  225 . 
         [0073]    The implant  100  differs from the implant  200  in that the implant  100  has anchoring filaments  115  provided from the tip region to an axially fixed, proximal head  125 , whereas the implant  200  has a predetermined length that is externally threaded with micro threads  230  to allow the head  225 , which has corresponding internal threads, to rotate about the implant, thus bringing the two adjacent tissues into approximation. In this regard, the implant  200  may be initially driven into the tissue, the distance to which is driven being limited by, e.g., friction between the implant  200  and the tissue. After the initial driving, the head  225  may be rotated, e.g., in a clockwise direction, to move the head or nut  225  distally along the longitudinal axis of the implant  200 . The rotation may be performed by a rotatable driver having projections configured to engage driving recesses  227  of the head  225 , as described in greater detail below. Although the head  225  has four evenly spaced recesses  227 , it should be understood that any appropriate number of recesses  227  may be provided. Further, the micro tightening nut or head  225  may have projections as an alternative or in addition to the recesses, the projections engageable by the driver to rotate the head  225 . Moreover, any other appropriate driving mechanism may be provided. For example, the driver may grip the outer surface of the head  225  to impart rotation via friction, or the radially outwardly facing surface of the head  225  may have one or more flat surfaces engageable by the driver. 
         [0074]    Contact between the distal face of the head  225  and the proximal surface of the proximal layer of tissue would in turn cause the proximal layer of tissue to move toward the distal layer of tissue, which is axially constrained by the filaments  215 . The head  225  may be prevented from rotating in the opposition direction by friction between the threads or any appropriate locking or securing mechanism, e.g., detents. During the tightening rotation of the head  225 , the body  205  may be prevented from rotating by the engagement of the filaments  215  with the tissue or any other appropriate mechanism. 
         [0075]    Each implant  100 ,  200  has a proximal surface  135 ,  235  via which a driving force may be applied. The proximal surface  135  of the implant  100  corresponds to the proximal surface of the proximal head  125 , while the proximal surface  235  of the implant  200  has a smaller diameter, which is the same or substantially the same as the diameter of the core  220 . 
         [0076]    Although the implants  100 ,  200  have cores  120 ,  220  and heads  125 ,  225  with circular cross sections, it should be understood that other cross-sections may be provided, e.g., rectangular, triangular, oval, polygonal, and/or any other regular or irregular shape. Further, it should be understood that the anchoring filaments  115 ,  215  may be evenly spaced apart or may have non-uniform spacing. Moreover, the filament density, i.e., the number of the filaments  115 ,  215  per unit of surface area of the core  120 ,  220  may be constant, or may vary. 
         [0077]    Modern manufacturing processes allow for near nano technology applications. This allows the implants  100 ,  200  to be manufactured in a size and complexity that may not have been possible in years past. The implant  100 ,  200  may be injection molded of either absorbable or non absorbable polymers and then processed to add the features of the protruding filaments  115 ,  215  and the threaded features  227 . The head  225  of the implant  200  is manufactured separately and to the same or similar tolerances so that the interface between the implant threads  230  and the head  225  of the implant  200  will thread precisely upon one another. 
         [0078]    Although the implants  100  and  200  are formed of polymer, it should be appreciated that any appropriate material may used, e.g., metal or a composite material. 
         [0079]    The materials and methods of manufacturing the implants  100  and  200  are applicable to any of the implants described herein. 
         [0080]    In order to accurately penetrate adjacent tissues that are not held or secured on a distal side, a rapid penetration of each layer of tissue may be required in order to affect penetration of both tissue layers. If an implant  100 ,  200  is applied slowly, the tissue may be pushed distally away by the implant and/or needle without adequate penetration. Thus, some example delivery mechanisms eject the implant a relatively high velocity. In some preferred examples, saline is used to pressurize the channel within the catheter or needle at such a rate that the plunger will eject the implant at the precise velocity. Other example embodiments utilize a spring-loaded mechanical mechanism to eject the implant. Further example embodiments push the implant using long push rods which run the length of the catheter. The ejection modality is computer-controlled. However, it should be understood that the ejection may be, e.g., operator-controlled. For example, the ejection force may be predetermined and repeatable by a mechanical system, e.g., a spring-loaded system, which is triggered by an operator, e.g., a surgeon. 
         [0081]      FIGS. 2A and 2B  are schematic illustrations of surgical implants  300  and  500  with driving mechanisms including catheters or needles  400  and  600 . 
         [0082]    Referring to  FIG. 2A , implant  300  shares many features in common with implants  100  and  200 . Implant  300  differs, however, in that it includes reverse threads  330  and a proximal head  325  having a driving recess  327 . The driving recess has a geometry that corresponds to a rotatable driver  405  of the catheter  400 , such that the driver  405  is insertable into the recess  327  to impart axial rotation to the implant  300 . In this regard, rotation of the driver in a first direction  410  causes the driver to rotate in the direction  410 . Although the direction  410  is clockwise (when view from a proximal location), it should be appreciated that the driver may be configured to rotate the implant  300  in the counter-clockwise direction, e.g., where the threading is reversed. The driver is configured to progressively move distally along its axis during driving to correspond to a distance which the implant is driven. The corresponding geometry of the driver  405  and the recess  327  may be selected to have any appropriate cross section, e.g., rectangular or hexagonal. 
         [0083]    The catheter has, at a distal end portion, a pair of retention tabs  415 . The retention tabs  415  have inner diameters that are less than the diameter of the proximal head  325  but greater than the diameter of the other, more distal portions of the implant  300 . Thus, the retention tabs allow the distal portions of the implant  300  to be driven beyond the distal end of the catheter and into tissue, but retains the head  325  within the catheter. After the driving of the implant  300 , the retention tabs may be actuated radially outwardly away from each other to allow the release of the head of the implant  300  and withdrawal of the catheter  400  away from the implant site. 
         [0084]    Referring to  FIG. 2B , the catheter  600  shares many features in common with the catheter  400 , including, e.g., retention tabs  615 , but differs in that it includes a spring driver  605 . The spring driver  605  imparts a spring force onto the proximal head  525  of the implant  500  to impart a rapid movement from an initial proximal position to an extended distal position. The spring driver  605  may have an initial preloaded position that is not in contact with the implant  500 . Thus, the spring and/or a driver portion driven by the spring may build momentum prior to engaging the implant  500 . This may be suitable for imparting a more aggressive acceleration to the implant  500 . When the implant is able to achieve a high speed quickly, it is able to pierce a proximal face  551  of the tissue and penetrate across the thickness of the tissue to the distal face  552 , rather than simply compressing the outer proximal surface  551  of the tissue. This may be particularly suitable in allowing a system that does not require any initial structure on the back side of the tissue during the driving process. 
         [0085]      FIG. 3  is a schematic illustration of a surgical implant  700  with a driving mechanism. The driving mechanism is a catheter  800  sharing features with the catheters  400  and  600  described above, including, e.g., retention tabs  815 , which are shown in their opened, or radially extended position, thereby allowing distal axial passage therethrough of the head  725  of the implant  700 . 
         [0086]    The implant  700  includes many features in common with the implants  100 ,  200 ,  300 , and  500  described above, but differs in that it includes a plurality of spring loaded tabs  702 , which may be formed, e.g., of a shape memory alloy, e.g., nitinol or spring-loaded steel. The spring-loaded tabs are maintained in their closed, or radially inward, position when the proximal free ends of the tabs  702  are axially disposed in the catheter  800  (in its closed position) and in the tissue through which the tabs are driven after piercing of the tissue, including a proximal face  751 , by the needle-like tip  710 . However, when the proximal ends of the spring loaded tabs  702  clear the distal side  752  of the tissue, the tabs are no longer radially constrained by the tissue and are able to spring radially outwardly into their open position. In the open position, the implant  700  is prevented or constrained from being proximally withdrawn through the tissue via contact between the extended tabs  702  and the distal surface  752  of the tissue. The nut or head  725  of the implant  700  may then be rotated and distally advanced as described above with regard to the head  225  of the implant  200  in order to bring the layers of tissue together. 
         [0087]    The driver may be configured to drive the any of the fasteners described herein to a predetermined depth. The precision of the depth may be accomplished by any appropriate mechanism, e.g., a precise hydraulic driving force, engagement with flanges or other similarly stops, or a filament/suture that tautens to limit the depth. Further the depth may be monitored using fluoroscopy or any other appropriate imaging mechanism. The driving mechanism may include pressurized saline or other hydraulic fluid that is pressurized through the endoscopic catheter shaft. Thus, very precise control may be accomplished. 
         [0088]      FIG. 4  shows a fastener or implant  250 . The fastener  250  includes features in common with the other fasteners disclosed herein and may be used in conjunction with any of the other fastening applications described herein. However, the fastener  250  includes a corrugated body  251 . The body  251  includes grooves  253  that extend axially along the length of the body  251 . Thus, extending circumferentially around the body  251 , a plurality of grooves  253  alternate with a plurality of ridges  255 . Further, the fastener body  251  includes a pair of split portions or devises  257  and  258 . The split portions are formed by respective splits or cuts  259  into the body  251 . In this regard, the splits  259  may be formed by making a cut radially into the body  251  and extending in an axial direction. Thus, the two split portions  257  and  258  are attached to the remainder of the body  251  at a distal position and extend proximally to free ends. The free ends include a plurality of sharp protrusions along a curved surface. These points are formed due to the corrugations. In particular, the ridges  255  form the sharp protrusions, as illustrated in the inset partial side view in  FIG. 4 , which are advantageous for gripping tissue and preventing distal sliding of the fastener  250 . Although each split portion  257  and  258  includes three such protrusions as illustrated, it should be understood that the fastener  250  may be designed such that one or more of the split portions has any other number of protrusions, including a single sharp protrusion. For example, if a larger number of sharp protrusions are desired, the body  251  could be more densely corrugated (i.e., a greater number of alternating grooves  253  and ridges  255  could be provided) and/or the angle of the cut or slice could be adjusted. Further, the length of proximal extension of the projections may be adjusted by varying the depth of the grooves  253  with respect to the ridges  255 . 
         [0089]    The split portions  257  and  258  do not substantially impede distal insertion into tissue but resist proximal movement from an insertion location by engaging the tissue. It has been discovered that the combination of the pointed and/or sharp-edged proximal ends of the split portions  257  and  258  with the alternating ridges on the proximal end of the split portions creates improved performance. 
         [0090]    Further, the split portions or wings  257  and  258  are axially offset from each other. For example, split  257  is axially located at position a along axis x and split  258  is axially located at position b along axis x. This allows for greater structural strength of the other portions of the body  251  as compared to a non-offset configuration. In particular, since the cuts progress continually radially inward as they progress distally, a non-offset portion would have a substantially smaller amount of material in cross-section in the distal end of the cut. This would lead to a mechanically weak point or region along the axis of the body and could lead to mechanical failure, especially in fasteners of small dimensions. 
         [0091]    The distal tip of the fastener  250  is pyramidal, with a sharp point, and a plurality of surfaces separated by edges that converge at the sharp point. Although four planar surfaces are provided, it should be appreciated that any appropriate suitable number of surfaces may be provided and that one or more or all of the surfaces may be non-planar. 
         [0092]    The fastener  250  also includes a hooked end portion  260 . The hooked portion may be suitable for coupling any other temporary and/or permanent implant. 
         [0093]    The fastener  250  may be produced by first forming the body  251  with the corrugations, e.g., by injection molding or extrusion, and subsequently forming clevises  257  and  258 , e.g., by cutting radially into the side of the body  251 . As illustrated, the cut is curved, with an angle (at the proximal entry point), relative to the longitudinal axis of the body  251 , that gradually decreases from the proximal initial cutting location toward the distal end of the fastener  250  and eventually becoming linear. Although the split or cut of the illustrated example is made with a curved or varying angle with respect to the longitudinal axis of the body  251 , it should be understood that any appropriate cut, including a linear cut, may be made. 
         [0094]    Although the fastener  250  includes two wings or split portions spaced equally around the radial periphery of the body  251 , it should be appreciated that any number of clevises, including a single clevis may be provided and at any appropriate spacing around the radial periphery. 
         [0095]    Furthermore, it should be understood that the corrugated split-bodied configuration may be employed in combination with any of the other fastener features disclosed herein. For example, the fastener  250  may have a split corrugated distal portion and a threaded proximal portion configured to receive a proximal head as disclosed in greater detail above, and/or include filaments in addition to the split portions. 
         [0096]      FIGS. 5A and 5B  illustrate a surgical micro implant or fastener  900 .  FIG. 5B  is a cross-sectional view of the surgical implant  900  with a cross-sectional plane extending along and including the longitudinal axis of the fastener  900  of  FIG. 5A . The fastener  900  includes many feature of the other example fasteners described herein. Further, the fastener includes a filament/suture  950  extending proximally from a proximal end of the fastener body  905 . In this regard, when a driver fires the fastener  900 , e.g., by application a saline or other precise hydraulic force or any other appropriate mechanism, the depth to which the fastener  900  is driven is limited by the amount of slack in the suture  950 . This may be accomplished by fixing a proximal end and/or other proximal portion of the suture  950  to a structure, e.g., a fixed position within the driver device, with a predetermined length and/or slack between the fixing location and the fastener body  905 . 
         [0097]    Referring to the cross-sectional view of  FIG. 5B , the suture  950  may extend longitudinally into an interior location of the fastener head  905 . An example manufacturing method may include molding, coextruding, or otherwise forming the fastener head  905  over the suture  950 . Coextrusion may be particularly advantageous. It should be appreciated however, that any appropriate manufacturing method may be employed. Further, although a suture  950  of non-stretchable material is provided, it should be understood that other materials, e.g., stretchable materials, may be provided. However, it may be preferable that, even if stretchable, the material have a predeterminable extension limit for particular driving momentums and/or applications. Further, a braided, non-braided, mono-filament, and/or multi-filament material may be provided. 
         [0098]    Although the fastener  900  includes micro filaments to anchor into a tissue and resist proximal dislocation after implantation, it should be understood that any other anchoring mechanism, e.g., wings or split portions as described above, may be provided. Moreover, any of the features disclosed with regard to the other example fasteners disclosed herein may be provided in conjunction with the fastener  900 . 
         [0099]      FIGS. 6A to 6C  schematically and sequentially illustrate the bringing into apposition of two tissues using a surgical implant  1300 , which shares many features in common with the other implants described herein. Implant  1300  has a distal anchoring portion with micro filaments and a proximal threaded portion configured to mate with an internally threaded head  1325 , analogous to the implant  200  described above. Implant  1300  also includes a proximally extending filament/suture  1350 , analogous to the implant  900  described above. 
         [0100]    Referring to  FIGS. 6A and 6B , a surgical system  1200  includes a handpiece  1202  configured to drive the fastener  1300  to a predetermined depth. The depth is limited, e.g., by a predetermined amount of slack in the suture  1350 . The proximal end of the suture  1350  is attached to a capstan  1205  configured to adjust the length of the suture  1350  extending from capstan  1205 . In this regard, the capstan  1205 , which may be actuated by a motor system or any other appropriate mechanism, may set the slack by reeling off a predetermined length of suture  1350  prior to driving the fastener  1300  and/or the capstan  1205  may have a predetermined amount of allowed rotation such that driving of the fastener  1300  causes the capstan  1205  to rotate only the predetermined amount, thereby setting the driving depth of the fastener  1300 . The determination of the depth and/or the driving velocity of the fastener  1300  may be determined in a processor  1210  of the handpiece  1202 . Although the processing takes place in a processor  1210  located in the handpiece  1202 , it should be understood that the processor may be disposed in other parts of the device, e.g., in the shaft  1215  and/or the processing may take place at a location separate from the handpiece  1202  and shaft  1215 , e.g., at a remote computing unit that communications, e.g., wirelessly, with the surgical device. Further, it should be understood that the capstan  1210  may be disposed in the shaft  1215 . 
         [0101]    Using any appropriate location determining mechanism, e.g., an imaging mechanism such as a fluoroscopy or ultrasound imaging unit, which may be located in the handpiece  1202 , shaft  1215  and/or an external device, the system  1200  determines the location of the first layer of tissue  980  and the second layer of tissue  990 . Depending on the application, it may be sufficient for the system  1200  to determine just the respective locations of the tissues  980  and  990 . The location may be an approximate location of the center of the tissue or a face, e.g., a proximal face, of each tissue. In the illustrated example, the system determines, e.g., via the imaging device and/or the processor  1210 , the respective positions of a first or proximal face  981  of the first tissue  980 , a second or distal face  982  of the first tissue  980 , a first or proximal face  991  of the second tissue  990 , and a second or distal face  992  of the second tissue  990  taken along the line or approximately along the line that the fastener  1300  is to be driven. Based on these positional values, the processor  1210  may determine the thickness of each tissue  980 ,  990  and the space between the distal face  982  of the first tissue  980  and the proximal face  991  of the second tissue, in addition to the location of each of the distal and proximal faces. Based on the these values, or a portion thereof, the system  1200 , e.g., via processor  1210 , calculates a precise distance and velocity to drive the fastener. The system  1200  may also take into account the features of the particular fastener being driven (e.g., dimensions, mass, and/or coefficient of friction) and/or the hardness and/or density of the tissue, which may be approximated, e.g., where the tissue is of a known or expected density and/or hardness, or determined based on the imaging data, e.g., fluoroscopy data. The velocity and/or distance may optionally be facilitated by incorporating empirical data into the algorithm or purely based. The depth is controlled, e.g., by precisely controlling the length of suture  1350  via the capstan  1215 . The velocity is precisely controlled, e.g., by a hydraulic driver, e.g., a saline driver. 
         [0102]    Where the shaft  1215  abuts the first or proximal face  981  of the tissue  980 , position of the first or proximal face  981  of the tissue  980  may be determined without using imaging. 
         [0103]    As illustrated in  FIG. 6A , after the shaft  1215  is placed adjacent the proximal face  981  of the first tissue  980  and the precise driving velocity and depth/position are determined, e.g., by processor  1210  in the handpiece  1205 , the system  1200  drives the fastener  1300  in the proximal direction indicated by arrow  1250  through the first tissue  980  across any gap between the first and second tissues  980  and  990 , and into the second tissue  990 , where the fastener  1300  anchors against distal retraction from the second tissue  990 . 
         [0104]    Referring to  FIG. 6B , the capstan  1210  is then actuated, e.g., by a motor system controlled by, e.g., processor  1210 , to proximally reel the suture  1350 , thereby drawing the fastener  1300 , along with the tissue  990  to which it is anchored, proximally toward the shaft  1215  and the first tissue  980  adjacent the shaft  1215 . The proximal direction of movement is indicated by arrow  1260  in  FIG. 6B . The first tissue  980  is restrained from proximal movement by, e.g., contact with the distal end of the shaft  1215 . 
         [0105]    As also illustrated in  FIG. 6B  the proximal head, or threaded nut,  1325  is moved distally, e.g., by a rotatable driver. The distal direction of movement is illustrated by arrow  1250  in  FIG. 6B . The proximal head  1325  may be moved distally at any point after the anchoring fastener  1300  is driven from the shaft  1215 . Once the fastener is pulled a sufficient proximal distance, the threaded proximal portion of the body of the fastener  1300  protrudes through the proximal face  981  of the first tissue  980 . The proximal head  1325  is then coupled to the threaded portion to form a threaded connection. A rotatable driver then rotates the head  1325  to distally drive the head  1325  to its implanted position, illustrated in  FIG. 6C . It should be understood than any final portion of the gap between the distal face  982  of the first tissue and the proximal face  991  of the second tissue  990  may be taken up by continuing to reel in the suture  1350  and/or driving the proximal head  1325  in the distal direction along the threads of the body of the fastener  1300 . 
         [0106]    After the proximal head  1325  has been fully driven on the threaded shaft of the fastener  1300 , the suture  1350 , or a portion thereof, may be separated from the fastener  1300 , e.g., by cutting. In this regard, the system  1200  may include a cutter or other trimming device, e.g., at the distal end of the shaft  1215 , in order to cut the suture  1350 . In applications where there is an undesired excess length of externally threaded shaft of the fastener  1300  extending proximally from the fully driven proximal head  1325 , the system  1200  may provide for trimming some or all of the excess. In this regard, the system may include a cutter or other trimming device, e.g., at the distal end of the shaft  1215 , which may be the same or different than the cutter for the suture  1350 , in order to remove some or all of the excess. 
         [0107]    Further although two tissues  980  and  990  are illustrated in  FIGS. 6A to 6C , it should be understood that the fastener may be driven through any desired number of tissue layers before reaching its anchored position. Moreover, any other example fasteners described herein may be formed with a suture and used in analogous manner to the fastener  1300 . 
         [0108]    During the procedure illustrated in  FIGS. 6A to 6C , the system  1200  may hydraulically drive the implant  1300  or use any other appropriate driving mechanism. Regarding hydraulic delivery, it is noted that a very precise force may be delivered at the distal end portion of the shaft  1215  to drive the fastener  1300 . This force may be controlled by the processor  1210  in connection with hydraulics, e.g., in the handpiece. For example, the hydraulic fluid, e.g., saline, may be disposed in a tube extending along the shaft  1215 . hydraulics and controls in the handpiece  1202  may then transmit a very precise force, via the hydraulic fluid extending along the shaft  1215 , to the distal end portion of the shaft  1215  to precisely drive the fastener  1300 . 
         [0109]      FIG. 7  is an illustration of a surgical implant  1000 . The fastener  1000  includes many feature of the other example fasteners described herein. Further, the fastener  1000  includes a proximal portion having a ratcheting mechanism including a micro ratcheting head  1025  and ratchet teeth  1030 . The ratcheting mechanism of the implant  1000  performs a function analogous to that of the micro threaded arrangement of the fastener  200  described above. However, as opposed to rotation of the head  225  about the threads  230  of the fastener  200 , the ratcheting head  1025  slides, e.g., linearly, along the fastener body  1005 . As each ratchet tooth  1030  or circumferential set of ratchet teeth  1030  is distally traversed, the proximal retraction of the head  1025  is resisted or prevented by the ratcheting engagement of a proximal surface of the head  1025  with a distal surface of the ratcheting tooth or teeth  1030 . In this regard, for each axial ratcheting position of the head  1025 , the fastener body  1005  may have any appropriate number of ratcheting teeth  1030 , including a single ratcheting tooth  1030 , arranged to engage the ratcheting head  1025 . Further, a single tooth  1030  may extend continuously around the entire radial periphery of the fastener body  1005 . 
         [0110]    Although the fastener  1000  includes micro filaments to anchor into a tissue and resist proximal dislocation after implantation, it should be understood that any other anchoring mechanism, e.g., wings or split portions as described above, may be provided. Moreover, any of the features disclosed with regard to the other example fasteners disclosed herein may be provided in conjunction with the fastener  1000 . 
         [0111]      FIG. 8  is an illustration of a distal end portion of a surgical implant  1100 . This distal arrangement may be provided on the distal end of any example fastener disclosed herein. The distal arrangement includes three concave surfaces  1105  that distally converge to form a sharp point  1110 . Separating the three concave surfaces  1105  are three tapered cutting edges  1115 . These tapered cutting edges  1115  may facilitate penetration of tissue, e.g., soft tissue. Although the end portion illustrated in  FIG. 8  includes three concave surfaces  1105  and separated by three corresponding tapered cutting edges  1115 , it should be understood that any appropriated number of concave surfaces  1105  and corresponding cutting edges  1115  may be provided. 
         [0112]    The various mechanisms described herein provide for a tissue repair system that allows great flexibility. For example, smaller defects may be repairable with a single fastener (e.g., fastener  100  or any other fastener described herein), and larger defects may be repairable with a plurality of fasteners, with or without a washer or plate  2200 , as described above. Larger defects, e.g., hernias or large holes, may be more suited for a mesh  1300  application, as described above. 
         [0113]    The various implants described herein, e.g., fasteners or anchors  100 ,  200 ,  300 ,  500 , and  700  and/or nuts  225 , may be formed by molding, e.g., injection molding. 
         [0114]    Further, any of the implantable elements described herein, e.g., fasteners  100 ,  200 ,  300 ,  500 , and  700  and/or nuts  225 , and/or sutures, may be formed wholly or partly of a material absorbable into the patient&#39;s body, or of a non-absorbable material, depending on, e.g., the specific application. For example, these elements may be formed of polyglycolic acid (PGA), or a PGA copolymer. These elements may also, or alternatively, be formed of copolymers of polyester and/or nylon and/or other polymer(s). Moreover, these elements may contain one or more shape-memory alloys, e.g., nitinol and/or spring-loaded steel. 
         [0115]    Absorbable materials may be advantageous where there is a potential for misfiring or improper locating of the various implants. For example, in a situation where a fastening arm  1100  drives a fastener at an unintended location, or where the tissue does not properly receive the implant, the fastener, e.g., fastener  100 , even where not needed, would relatively harmless, as it would eventually absorb into the patient&#39;s body. 
         [0116]    Although the present invention has been described with reference to particular examples and exemplary embodiments, it should be understood that the foregoing description is in no manner limiting. Moreover, the features described herein may be used in any combination.