Patent Publication Number: US-2010114119-A1

Title: Tacking Device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/111,074 filed on Nov. 4, 2008, entitled “TACKING DEVICE,” the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     The present embodiments relate generally to medical devices, and more particularly, to apparatus and systems for coupling a graft member to tissue. 
     Perforations in tissue or bodily walls may be formed intentionally or unintentionally. For example, an unintentional ventral abdominal hernia may be formed in the abdominal wall due to heavy lifting, coughing, strain imposed during a bowel movement or urination, fluid in the abdominal cavity, or other reasons. 
     Intentional perforations may be formed, for example, during surgical procedures such as translumenal procedures. In a translumenal procedure, one or more instruments, such as an endoscope, may be inserted through a visceral wall, such as the stomach wall. During a translumenal procedure, a closure instrument may be used to close the perforation in the visceral wall. Depending on the structure comprising the perforation, it may be difficult to adequately close the perforation and prevent leakage of bodily fluids. 
     Attempts to seal perforations have been attempted by coupling a graft member to tissue. For example, during hernia repair, a graft material such as a mesh or patch may be disposed to cover the perforation. The graft material may completely overlap with the perforation, and the edges of the graft material may at least partially overlap with tissue surrounding the perforation. The graft material then may be secured to the surrounding tissue in an attempt to effectively cover and seal the perforation. 
     In order to secure the graft material to the surrounding tissue, sutures commonly are manually threaded through the full thickness of the surrounding tissue. In the case of a ventral abdominal hernia, the sutures may be threaded through the thickness of the abdominal wall, then tied down and knotted. However, such manual suturing techniques may be time consuming and/or difficult to perform. 
     In addition to covering and sealing perforations, there are various other instances in which it may be desirable to couple a graft material to tissue. For example, it may become desirable to couple the graft material to a region of tissue for purposes of reconstructing the local tissue. An exemplary tacking device used to couple graft material to tissue is described in U.S. Application No. 61/047,293 filed Apr. 23, 2008, the disclosure of which is incorporated herein by reference in its entirety. Likewise, there are other instances where tacking devices may be used without a graft, such as for directly closing an opening in tissue. Exemplary methods for closing an opening in tissue are described in U.S. application Ser. No. 12/557,232 (Attorney Docket No. 10000-1692) filed Sep. 10, 2009, and U.S. application Ser. No. 12/557,204 (Attorney Docket No. 10000-1681) filed Sep. 10, 2009, the disclosures of which are incorporated herein by reference in their entirety. 
     SUMMARY 
     The present embodiments provide apparatus and systems suitable for coupling a graft member to tissue or closing an opening in tissue. In one embodiment, a tacking device is provided comprising a wire having a proximal end and a distal end. The proximal and distal ends each have delivery states suitable for delivery to a target site, and further each comprise deployed states. The distal end is configured to engage tissue at a first location in the deployed state, and the proximal end is configured to engage the graft member in the deployed state to secure the graft member to the tissue. 
     In one embodiment, the wire may comprise an S-shape in the deployed state. The S-shape includes configurations where the proximal and distal ends of the wire are preferably curved, and the ends of the wire extend laterally away from each other in different directions in the deployed state. The degree of curvature of each end may range anywhere from about 90 degrees to about 360 degrees. When the curvature of the wire approaches 180 degrees, an elongated “S” is formed, and the wire forms a more compact “S”, or figure-eight shape, when the curvature is about 360 degrees. The wire may comprise a nickel-titanium alloy that is configured to self-deploy to the S-shape. In another embodiment, the proximal end and the distal end of the wire may curve laterally toward each other to form a C-shape. 
     The tacking device may be delivered to a target site using an insertion tool comprising a hollow lumen having an inner diameter configured to receive the wire. The wire is configured to be held in the delivery state when disposed within the hollow lumen. In the delivery state, the wire may be oriented in a substantially longitudinal direction with respect to the insertion tool. The insertion tool maintains the wire in the delivery state. 
     In use, the graft member may be positioned over a selected region of tissue. The insertion tool may be advanced distally to penetrate through the graft member and through a portion of the tissue. The insertion tool then may be proximally retracted with respect to the tacking device to cause the distal end of the wire to deploy and engage the tissue. Further translation of the insertion tool with respect to the tacking device may cause the proximal end of the wire to deploy and engage the graft member. A stylet loaded into the hollow lumen may abut the proximal end to facilitate retraction of the insertion tool with respect to the tacking device. If desired, multiple tacking devices may be sequentially loaded within the hollow lumen of the insertion tool and then sequentially deployed to secure the tissue to the graft material at multiple different locations. Related procedures may be used without the graft material in order to close a perforation using the tacking device, where both ends of the tacking device engage the tissue. 
     According to the more detailed aspects, the tacking device preferably comprises one single wire, so it may impose less friction on the interior wall of the insertion tool. It may be easier to load into the insertion tool as well, thereby making loading multiple tacking devices into the insertion tool less time-consuming. Further, the reduction in friction resulting from using a single wire may make it easier to deploy the tacking device from the insertion tool. 
     Embodiments of the tacking device are also designed in a way to accommodate different thicknesses of tissue. Once fully deployed, if the tissue is thin, in one embodiment the tacking device will simply double back on itself. If the tissue is thick, then the tacking device will stretch out more longitudinally resulting in more of an elongated S shape. In another embodiment, the tacking device will form a closed C shape when the tissue is thin, or may stretch out to form more of an elongated C shape when the tissue is thick. 
     Optionally, at least one loop member configured to receive a suture may be used for further securing the graft member to the tissue. The loop member may be integrally formed within the wire by bending a portion of the wire 360 degrees so that a loop is formed within the wire, or the loop may be formed by adding an arch-shaped segment of wire to the tacking device. In use, multiple tacking devices comprising loop members may be deployed, and a suture may be threaded through the loop members and actuated in a purse-string fashion. 
     Other systems, methods, features and advantages of the invention will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be within the scope of the invention, and be encompassed by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a plan view of a tacking device. 
         FIG. 2  is another plan view of a tacking device. 
         FIG. 3  is another plan view of a tacking device. 
         FIG. 4  is another plan view of a tacking device. 
         FIG. 5  is a perspective view of a distal region of an insertion tool and the tacking device of  FIG. 1 . 
         FIG. 6  is a perspective, cut-away view illustrating multiple tacking devices in a delivery state. 
         FIG. 7  is a schematic view illustrating a ventral hernia. 
         FIG. 8  is a schematic view illustrating a graft member used to cover the ventral hernia of  FIG. 7 . 
         FIG. 9  is a schematic view of a method step for treating the ventral hernia of  FIG. 5 . 
         FIG. 10  is a side-sectional view taken along line A-A of  FIG. 9 . 
         FIG. 11  is a side-sectional view showing multiple tacking devices positioned in deployed states. 
         FIG. 12  is a schematic view illustrating multiple deployed tacking devices used to treat the ventral hernia of  FIG. 7 . 
         FIG. 13  is a side-sectional view illustrating a tacking device in the deployed state engaged with tissue of a certain thickness. 
         FIG. 14  is a side-sectional view illustrating a tacking device in the deployed stated engaged with tissue of a certain thickness. 
         FIG. 15  is a plan view of an alternative tacking device. 
         FIG. 16  is a plan view of another alternative tacking device. 
         FIG. 17  is a side-sectional view illustrating one method of use of multiple tacking devices of  FIG. 16 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the present application, the term “proximal” refers to a direction that is generally towards a physician during a medical procedure, while the term “distal” refers to a direction that is generally towards a target site within a patient&#39;s anatomy during a medical procedure. 
     Referring now to  FIG. 1 , one embodiment of a tacking device  20  is shown constructed in accordance with the teaching of the present invention. In this embodiment, the tacking device  20  comprises a single wire having a proximal end  24  and a distal end  26  connected by an intermediate section  22 . In the embodiment of  FIG. 1 , the proximal end  24  and the distal end  26  are in the deployed state. Since the device is symmetrical, it may be loaded into an insertion tool with either end first (i.e., the proximal and distal ends  24  and  26  are interchangeable), as explained further below. The embodiment of  FIG. 1  is operable between a deployed state and a delivery state. As shown in  FIG. 1 , the natural unbiased state of the wire is the deployed state. In the delivery state, the tacking device  20  is generally straight, thereby aligning itself with a longitudinal axis  28 , as shown by tacking device  20   a  in  FIG. 6 . 
     In the embodiment of  FIG. 1 , the curvature of the proximal and distal ends  24  and  26  spans about 330 degrees (plus or minus 15 degrees) in the deployed state, such that the S shape approximates a figure-eight. In this embodiment, the intermediate section  22  remains generally straight in the deployed state. The proximal and distal ends  24  and  26  of this embodiment extend laterally in different directions from the longitudinal axis  28 . Looking at  FIG. 1 , the curvature of the distal end  26  faces in one direction away from the longitudinal axis  28 , while the curvature of the proximal end  24  faces in the opposite direction. The proximal and distal ends  24  and  26  need not be co-planar (e.g., they could be rotated 90 degrees from each other). 
     The dimensions of the tacking device  20  may be tailored based on a particular surgical procedure, a particular patient&#39;s anatomy and/or other factors. However, for illustrative purposes, the longitudinal length of the tacking device  20  preferably ranges from about 0.30 mm to about 0.50 mm in the delivery state, and is most preferably about 0.37 mm. The longitudinal distance L 1  between the ends  24  and  26  may range from about 0 mm to about 0.60 mm, depending on tissue thickness. The diameter of the wire preferably ranges from about 0.008 mm to about 0.024 mm, and most preferably is about 0.016 mm. Such dimensions are provided for reference purposes only and are not intended to be limiting 
     The tacking device  20  may comprise any suitable shape and material. Solely by way of example, the tacking device  20  may comprise stainless steel or a biocompatible plastic. The tacking device  20  may comprise any shape-memory material, such as a nickel-titanium alloy (nitinol). If a shape-memory material such as nitinol is employed, the tacking device  20  may be manufactured such that it can assume the preconfigured deployed state shown in  FIG. 1  upon application of a certain cold or hot medium. More specifically, a shape-memory material may undergo a substantially reversible phase transformation that allows it to “remember” and return to a previous shape or configuration. For example, in the case of nitinol, a transformation between an austenitic phase and a martensitic phase may occur by cooling and/or heating (shape memory effect) or by isothermally applying and/or removing stress (superelastic effect). Austenite is characteristically the stronger phase and martensite is the more easily deformable phase. 
     In an example of the shape-memory effect, a nickel-titanium alloy having an initial configuration in the austenitic phase may be cooled below a transformation temperature (M f ) to the martensitic phase and then deformed to a second configuration. Upon heating to another transformation temperature (A f ), the material may spontaneously return to its initial, predetermined configuration, as shown in  FIG. 1 . Generally, the memory effect is one-way, which means that the spontaneous change from one configuration to another occurs only upon heating. However, it is possible to obtain a two-way shape memory effect, in which a shape memory material spontaneously changes shape upon cooling as well as upon heating. 
     Alternatively, the tacking device  20  may be made from other metals and alloys that are biased, such that they may be restrained by the insertion tool  50  prior to deployment, but are inclined to return to their relaxed, deployed state upon deployment. Solely by way of example, the tacking device  20  may comprise other materials such as stainless steel, cobalt-chrome alloys, amorphous metals, tantalum, platinum, gold and titanium. The tacking device  20  also may be made from non-metallic materials, such as thermoplastics and other polymers. 
     While one embodiment of the tacking device  20  is shown in  FIG. 1 , the tacking device may comprise various shapes suitable for engaging, penetrating and/or abutting tissue, for purposes explained further below, and need not necessarily assume the deployed shape depicted in  FIG. 1 . In  FIG. 2 , a second embodiment of a tacking device  20  is shown constructed in accordance with the teaching of the present invention. In this embodiment, the degree of curvature of the proximal and distal ends  24  and  26  is less than the embodiment of  FIG. 1  so that the tacking device  20  forms more of an elongated S shape with the proximal and distal ends  24  and  26  in their deployed states. In  FIGS. 3 and 4 , a third and fourth embodiment of a tacking device  20  are shown constructed in accordance with the teaching of the present invention. In these embodiments, the proximal and distal ends  24  and  26  move laterally away from the longitudinal axis  28  in the same direction to form a “C” shape. In addition, while the embodiments of  FIGS. 1-4  show a tacking device  20  comprised of a single wire, the terms wire or single wire are intended to include monofilament or multifilament wires, the latter of which may be wound, braided, woven, wrapped, or otherwise joined to form a wire. The wire of the tacking device  20  may thus include platinum, gold, nitinol, steel or other radiopaque metal wires wrapped around a core wire, which together form the “single wire” tacking devices as described herein. See, e.g., U.S. Pat. No. 5,330,482, the entire disclosure of which is incorporated herein by reference. The wire of the tacking device  20  could also be two or more wires interwoven together, of the same or different material, for example one or two nitinol wires and one stainless steel wire interwoven together to form the S shape or C shape tacking devices as described above. 
     Referring to  FIGS. 1-6 , the proximal and distal ends  24  and  26  each comprise a delivery state, as shown in  FIG. 6  below, and further comprise a deployed state, as shown in  FIGS. 1-4 . In all of the embodiments, each of the ends  24  and  26  comprise a hook-shape in the deployed state. The ends  24  and  26  retroflex preferably between about 90 degrees to about 360 degrees in the deployed state and preferably are circular or semi-circular. In the embodiments depicted in  FIGS. 1 and 2 ,  FIG. 1  depicts a curvature of about 330 degrees, while  FIG. 2  depicts a curvature of about 120 degrees. Where the ends  24  and  26  have a curvature of about 180 degrees so that the tacking device  20  forms even more of an elongated S shape than depicted in  FIG. 2 , the proximal and distal ends  24  and  26  are oriented substantially parallel to the intermediate section  22 . When the ends  24  and  26  have a curvature of about 330 degrees or greater, the proximal and distal ends  24  and  26  are oriented substantially perpendicular to the intermediate section  22  as shown in  FIG. 1 . In the embodiments depicted in  FIGS. 3 and 4 ,  FIG. 3  illustrates a tacking device with more of a closed C shape, while  FIG. 4  shows a tacking device with more of an elongated C shape. The degree of curvature for all embodiments may range anywhere from about 90 degrees to about 360 degrees. 
     The degree of curvature may also vary based on tissue thickness. For example,  FIGS. 13 and 14  depict a tacking device  20  engaging tissues of varying thicknesses t 1 . In  FIG. 13 , where the tissue thickness t 1  is thin, the tacking device  20  forms more of a figure-eight shape as depicted in  FIG. 1 . In  FIG. 14 , where the tissue thickness t 1  is thicker, the tacking device  20  forms more of an S shape as depicted in  FIG. 2 . The intermediate section  22  has been shown generally straight in the embodiments depicted in  FIGS. 1-4 , although it could be curved. 
     Further, a longitudinal distance L 1  between the ends  24  and  26  of the tacking device  20  may be varied to engage tissue in a desirable manner. For example, the longitudinal distance L 1  may be dimensioned to be substantially equal to or less than the combined thickness t i  and t 2  of a tissue  74  and a graft member  80 , respectively, as shown in  FIG. 8  below, when the tacking device  20  is retroflexed, thereby providing a desired compressive force upon the tissue  74  and the graft member  80 . The overall length of the tacking device  20  also may be varied to engage tissue in a desirable manner. 
     As noted above, the tacking device  20  may comprise any shape suitable for engaging, penetrating and/or abutting tissue, for purposes explained further below, and need not necessarily assume the curved S shape or curved C shape depicted in  FIGS. 1-4 . For example, for the embodiments depicted in  FIGS. 1-4 , the proximal ends  24  and distal ends  26  may move laterally away from the longitudinal axis  28  such that the proximal ends  24  form up to about 90 degree angles from the distal ends  26 . 
     Referring to  FIGS. 5-6 , one or more tacking devices  20  may be delivered to a target site in a patient&#39;s anatomy using an insertion tool  50 . In one embodiment, the insertion tool  50  is capable of carrying multiple different tacking devices, such as six tacking devices  20   a - 20   f , as shown in  FIG. 12  and described below. In  FIG. 6 , one complete tacking device  20   a  is shown in the straightened delivery state, while portions of the distal end  26   b  of another tacking device  20   b , and the proximal end  24   f  of another tacking device  20   f , are also shown. Any embodiment of the tacking device of this invention is generally straight in the delivery state, as depicted in  FIG. 6 . 
     In one embodiment, the insertion tool  50  comprises a needle-like body having a sharpened distal tip  52  and a hollow lumen  54 , as shown in  FIGS. 5-6 . The insertion tool  50  may be manufactured from stainless steel or any other suitable material, and may comprise an endoscopic ultrasound (EUS), or echogenic, needle. Solely by way of example, the insertion tool  50  may comprise the EchoTip® Ultrasound Needle, or the EchoTip® Ultra Endoscopic Ultrasound Needle, both manufactured by Cook Endoscopy of Winston-Salem, N.C. 
     The hollow lumen  54  of the insertion tool  50  may comprise an inner diameter that is larger than an outer diameter of the tacking device  20 . The hollow lumen  54  may further comprise an inner diameter that is less than twice the outer diameter of the tacking device  20 . One or more tacking devices, such as six tacking devices  20   a - 20   f , may be loaded into the hollow lumen  54  in a delivery state, as shown in  FIG. 6 . In the delivery state, the proximal and distal ends  24  and  26  of each tacking device  20   a - 20   f  may comprise a substantially longitudinally-oriented profile, i.e., oriented along a longitudinal axis of the insertion tool  50 . 
     The multiple tacking devices  20   a - 20   f  may be inserted into the hollow lumen  54  of the insertion tool  50  in a sequential manner, whereby the proximal end  24   a  of the first tacking device  20   a  may abut the distal end  26   b  of the second tacking device  20   b , as depicted in  FIG. 6 . The insertion tool  50  maintains the tacking devices in the delivery state. The distal end  26   a  of the first tacking device  20   a  may be loaded a distance away from the sharpened distal tip  52  of the insertion tool  50  to prevent inadvertent deployment. 
     A stylet  60  may be disposed for longitudinal movement within the hollow lumen  54  of the insertion tool  50 , as shown in  FIG. 6 . The stylet  60  may comprise stainless steel or any other suitable material. The stylet  60  is disposed proximal to the proximal end  24   f  of the final sequential tacking device  20   f , as shown in  FIG. 6 . During use, the insertion tool  50  may be proximally retracted, while the stylet  60  may be held longitudinally steady, to facilitate sequential deployment of each of the tacking devices  20   a - 20   f , as explained further below. 
     To facilitate the deployment of multiple tacking devices  20 , it may be helpful to monitor the degree of retraction of the insertion tool  50 . For example, the stylet  50  may comprise one or more markers (not shown), which may be disposed near the proximal end of the stylet  60  so that a physician may determine how far the insertion tool  50  has been retracted. In another embodiment, the stylet  50  may comprise indentations for tactile feel (not shown), which may be disposed at any point along the length of the stylet  60  so that a physician may determine by feel how far the insertion tool  50  has been retracted. Likewise, the handle assembly may comprise stops (not shown) that cooperate with corresponding features disposed near the proximal end of the stylet  60 , so that a physician may determine how far the insertion tool  50  has been retracted. Finally, spacers may be employed between the tacking devices  20  to ensure one device is ejected at one time. 
     The insertion tool  50  may comprise one or more markers  56 , as shown in  FIGS. 5-6 , which may be disposed near the distal end of the insertion tool  50 . The markers  56  may be configured to be visualized under fluoroscopy or other imaging techniques to facilitate location of the distal end of the insertion tool, for example, so that a physician may determine how far the insertion tool  50  has penetrated into tissue  74 , as depicted in  FIGS. 9-10 . Optionally, a sheath member  58  having an inner diameter larger than an outer diameter of the insertion tool  50 , as shown in  FIG. 5 , may be longitudinally advanced over the insertion tool  50 , for various purposes explained further below. As will be explained further below, the insertion tool  50  may be used in conjunction with another device, such as an endoscope, and may be delivered through a working lumen of an endoscope or similar device. 
     Referring now to  FIGS. 7-12 , one or more tacking devices  20  described above may be used to facilitate treatment of a perforation  75  using a graft member  80 . In the example shown, the perforation  75  is a ventral hernia located in the abdominal wall  74 . The right and left legs  72  and  73  of a patient  70  are shown for illustrative purposes. While treatment of a ventral hernia is shown for illustrative purposes, it will be apparent that the tacking devices described herein may be used in a wide range of medical procedures, including but not limited to any exemplary procedures described herein. 
     The initial stages of the ventral hernia repair may be performed using techniques that are known. Specifically, an open technique or laparoscopic technique may be employed. In an open technique, an incision may be made in the abdominal wall and fat and scar tissue may be removed from the area. A graft member  80  then may be applied so that it overlaps the perforation  75 , preferably by several millimeters or centimeters in each direction, as depicted in  FIG. 8 . In a laparoscopic technique, two or three smaller incisions may be made to access the hernia site. A laparoscope may be inserted into one incision, and surgical instruments may be inserted into the other incision(s) to remove tissue and place the graft member  80  in the same position as the open procedure. 
     The graft member  80  may comprise any suitable material for covering the perforation  75  and substantially or entirely inhibiting the protrusion of abdominal matter. In one embodiment, the graft member  80  may comprise small intestinal submucosa (SIS), such as SURGISIS® BIODESIGN™ Soft Tissue Graft, available from Cook Biotech, Inc., West Lafayette, Ind., which provides smart tissue remodeling through its three-dimensional extracellular matrix (ECM) that is colonized by host tissue cells and blood vessels, and provides a scaffold for connective and epithelial tissue growth and differentiation along with the ECM components. Preferably, the graft member  80  would be a one to four layer lyophilized soft tissue graft made from any number of tissue engineered products. Reconstituted or naturally-derived collagenous materials can be used, and such materials that are at least bioresorbable will provide an advantage, with materials that are bioremodelable and promote cellular invasion and ingrowth providing particular advantage. Suitable bioremodelable materials can be provided by collagenous ECMs possessing biotropic properties, including in certain forms angiogenic collagenous extracellular matrix materials. For example, suitable collagenous materials include ECMs such as submucosa, renal capsule membrane, dermal collagen, dura mater, pericardium, fascia lata, serosa, peritoneum or basement membrane layers, including liver basement membrane. Suitable submucosa materials for these purposes include, for instance, intestinal submucosa, including small intestinal submucosa, stomach submucosa, urinary bladder submucosa, and uterine submucosa. The graft member  80  may also comprise a composite of a biomaterial and a biodegradable polymer. Additional details may be found in U.S. Pat. No. 6,206,931 to Cook et al., the disclosure of which is incorporated herein by reference in its entirety. 
     Referring now to  FIGS. 9-10 , after the graft member  80  has been placed to cover the perforation  75 , the insertion tool  50  may be advanced in a distal direction to pierce through the graft member  80 , and further may pierce at least partially into the tissue  74  at a first location around the perimeter of the perforation  75 . In this example, the insertion tool  50  is carrying six sequential tacking devices  20   a - 20   f , which may be disposed within the hollow lumen  54  of the insertion tool  50  as shown and explained with respect to  FIG. 6  above. With each of the tacking devices  20   a - 20   f  in the delivery states, the sharpened tip  52  of the insertion tool  50  may be advanced to a predetermined depth into the tissue  74 . The markers  56  of  FIGS. 5-6  may facilitate in determining how far the insertion tool  50  has penetrated into tissue  74 , as depicted in  FIG. 10 . 
     In a next step, the stylet  60  of  FIG. 6  may be held steady with respect to the insertion tool  50 , while the insertion tool  50  is retracted in a proximal direction. This causes the distal end  26  of the most distal tacking device  20   a  to extend distally to the sharpened tip  52  of the insertion tool  50 , as depicted in  FIG. 10 . When the distal end  26  is no longer radially constrained by the insertion tool  50 , it may assume its predetermined deployed state in which it may engage, penetrate and/or abut the tissue  74 . As the insertion tool  50  further is retracted proximally with respect to the tacking device  20   a , the proximal end  24  may assume its predetermined deployed state when it is no longer radially constrained, as shown in  FIG. 11 . In the deployed state, the proximal end  24  may engage, penetrate and/or abut the graft member  80  and optionally penetrate into the tissue  74 . In this manner, the tacking device  20   a  helps secure the graft material  80  against the tissue  74 . In particular, the substantially 360-degree hook-shaped configuration of the proximal end  24  may urge the graft member  80  in a distal direction towards the tissue  74 . 
     After the first tacking device  20   a  has been deployed, the insertion tool  50  may be repositioned to deploy another tacking device around the perimeter of the perforation  75 . Each subsequent tacking device  20   b - 20   f  may be deployed in the same manner as the tacking device  20   a . In this manner, the tacking devices  20   a - 20   f  may secure the graft member  80  around the perimeter of the perforation  75 , as shown in  FIG. 12 . As will be apparent, greater or fewer tacking devices may be used, and the positioning of the tacking devices may be varied to optimize securing the graft member  80  to the tissue  74  in order to substantially seal the perforation  75 . 
     Optionally, the sheath member  58  of  FIG. 5  may be longitudinally advanced over the insertion tool  50 , for example, if needed to protect the sharpened distal tip  52  of the insertion tool  50  while the insertion tool  50  is being repositioned. Further, the sheath member  58  may be advanced distally over the insertion tool  50  to facilitate deployment of the proximal end  24 . For example, the sheath member  58  may periodically push against the graft member  80 , thereby temporarily urging the graft member  80  and/or the tissue  74  in a distal direction. At this time, the sheath member  58  may be held steady while the insertion tool  50  is retracted proximally to deploy the proximal end  24  at a location proximal to the compressed tissue  74  and graft member  80 . Once the proximal end  24  has been deployed, the compressive force applied by the sheath member  58  may be removed so that the deployed proximal end  24  may engage the graft member  80  and the tissue  74 . 
     In the embodiment of  FIGS. 7-12 , the tissue  74  illustratively comprises a thickness t 1 , while the graft member  80  comprises a thickness t 2 . The distal end  26  may be deployed entirely within the tissue  74 , as depicted in  FIG. 11 , or alternatively may be deployed substantially distal to the tissue  74  while abutting or piercing through a distal edge of the tissue  74 . In the latter embodiment, the longitudinal distance L 1  between the ends  24  and  26  of the tacking device  20  may be dimensioned to be substantially equal to, or slightly less than, the combined thickness t 1 +t 2  of the tissue  74  and the graft member  80 . The longitudinal distance L 1  may be otherwise sized and configured, as desired, to apply desired forces upon the graft member  80  and the tissue  74 . 
     While  FIGS. 7-12  have illustrated the use of one or more tacking devices  20  for covering a perforation  75  formed in the ventral abdominal wall, the tacking devices disclosed herein may be useful in many other procedures. Solely by way of example, one or more tacking devices  20  may be used to treat perforations in a visceral wall, such as the stomach wall. In such cases, a suitable insertion device, such as an endoscope, may be advanced through a bodily lumen such as the alimentary canal to a position proximate the target location. One or more components may be advanced through a working lumen of the endoscope. To close the perforation, the graft member  80  may cover the perforation and may be secured in a position overlapping the perforation using the one or more of the tacking devices  20 , which may be deployed using the techniques described hereinabove. 
     As mentioned above, the tacking devices of this invention may also be used for closing an opening in tissue. Referring to  FIGS. 7-14 , the same steps may be utilized to secure a graft material to tissue may be used to have the tacking device directly engage a perforation in tissue instead of engaging a perforation and a graft material. When the tissue is thin, as depicted in  FIG. 13 , then one embodiment of the tacking device will form more of a figure-eight shape in the deployed state as depicted in  FIG. 1 . When the tissue is thick, as depicted in  FIG. 14 , one embodiment of the tacking device will form more of an elongated S shape as shown in  FIG. 2 . 
     Referring now to  FIGS. 15 and 16 , in an alternative embodiment, tacking devices  21  or  23  may comprise one or more features for facilitating suturing, and preferably purse-string suturing. The tacking devices  21  and  23  are similar to the tacking device  20  of  FIGS. 1-4 , except as noted below. The tacking devices  21  and  23  comprise proximal and distal ends  24  and  26 , respectively. In one embodiment, the tacking device  21  comprises a proximal end and a distal end with a loop  27  formed at any point along its length, preferably formed as shown in  FIG. 15  by bending a region of the wire that is disposed near the proximal end. The tacking device may be bent to form an annular loop member  27  having an aperture  29 . In the embodiment of  FIG. 16 , a segment of wire may be added to tacking device  23  to form an annular loop member  31  having an aperture  29 . A suture may be threaded through the aperture of the loop member  31 , for example, as shown in  FIG. 17  below. While the loop member  31  of  FIG. 16  is shown substantially near the proximal end  24 , it may be placed closer to the distal end  26  of the tacking device  23 . 
     Referring now to  FIG. 17 , an exemplary method of using the tacking device  23  is shown. In one step, a graft member  80  may be placed over a perforation  75 , and multiple tacking devices may be deployed using an insertion device to secure the graft member  80  to the tissue  74 , as explained in detail above with respect to  FIGS. 7-12 . In the embodiment of  FIG. 17 , multiple tacking devices may be linked together by a single suture  34 , which may be slidably coupled through the loop members of each of the tacking devices  23 , as generally shown in  FIG. 17 . There are two free ends  33  and  35  of the suture  34 , which may be independently tensioned to facilitate closure of the perforation  75 . 
     Preferably, multiple tacking devices having loop members are sequentially positioned around the perforation  75  in a semi-annular or annular shape, for example, as shown above in  FIG. 12 . The ends of the suture are then tensioned to reduce the distance between the tacking devices and compress the tissue  74  around the perforation  75 . The suture ends may be secured to maintain the compression of the tissue  74  using any suitable technique such as by forming a knot or using clamps, rivets and the like. 
     Further, in lieu of the loop members described herein, other mechanisms for engaging and/or retaining sutures may be integrally formed with the tacking device or externally attached thereto. Solely by way of example, such suture retaining mechanisms are explained in pending U.S. patent application Ser. No. 11/946,565, filed Nov. 28, 2007, and U.S. patent application Ser. No. 12/125,528, filed May 22, 2008, the entire disclosures of which are hereby incorporated by reference in their entirety. 
     Various types of sutures may be used in conjunction with embodiment of  FIGS. 15-17 . For example, synthetic sutures may be made from polypropylene, nylon, polyamide, polyethylene, and polyesters such as polyethylene terephthalate. These materials may be used as monofilament suture strands, or as multifilament strands in a braided, twisted or other multifilament construction. 
     While the examples shown above have illustratively described a tacking device that may be useful for coupling a graft member to tissue to cover and seal a perforation, the tacking devices  20 ,  21  and  23  may be used in other procedures. As noted above, the tacking devices  20 ,  21  and  23  may be used to treat bodily walls during translumenal procedures. Further, the tacking devices  20 ,  21  and  23  may be used to secure a graft member to tissue for reconstructing local tissue, and the like. 
     In yet further applications within the scope of the present embodiments, the tacking devices  20 ,  21  and  23  need not be used for coupling a graft member to tissue. For example, the tacking devices  20 ,  21  and  23  may be used in an anastomosis procedure. In order to create an anastomosis, for example, multiple tacking devices  20 ,  21  or  23  may be deployed in a circular manner to couple a proximal vessel, duct or organ to a distal vessel, duct or organ. In such cases, a suitable insertion device, such as an endoscope, may be advanced through a bodily lumen such as the alimentary canal to a position proximate the target location. One or more components, such as the insertion tool  50 , may be advanced through a working lumen of the endoscope. The distal end of the insertion tool  50  may be viewed under fluoroscopy, or via optical elements of the endoscope, or by some other visualization technique. Under suitable visualization, multiple tacking devices then may be delivered at one time, for example, using the insertion tool  50 . Then, a hole may be punched through the middle of the deployed tacking devices to create a flow path between the proximal and distal vessels/ducts/organs. It will be apparent that still further applications of the tacking devices  20 ,  21  and  23  are possible. Moreover, the insertion tool  50  may be used with or without an endoscope or similar device. 
     While various embodiments of the invention have been described, the invention is not to be restricted except in light of the attached claims and their equivalents. Moreover, the advantages described herein are not necessarily the only advantages of the invention and it is not necessarily expected that every embodiment of the invention will achieve all of the advantages described.