Abstract:
A method of preparing a sling combination is described. The method comprises the steps of providing a sling formed of a biocompatible material and having a body comprising two ends; mounting the sling on a first tack at a first end of the body of the sling; and mounting the first stack on a tacking device.

Description:
FIELD OF THE INVENTION 
     The present invention relates to methods and apparatus for treating incontinence, especially by bladder neck support. 
     BACKGROUND OF THE INVENTION 
     Urinary incontinence is an unfortunately common medical complaint. Many treatments have been suggested. Recently, a relatively minimally invasive technique has become more common, in which a bladder neck and/or urethra is supported by a sling, so that the urethra is partially compressed and/or has a support below it so that during straining and/or bladder/uretheral descent, pressure is applied between the urethra and the sling, thereby closing its lumen. 
     Benderev et. al, in U.S. Pat. No. 5,836,314 and Brenneman et al, in PCT publication WO 98/19606, the disclosures of which are incorporated herein by reference, describe exemplary procedures for treating incontinence. Two or more bone anchors are attached to the pubic bone. Each anchor is pre-threaded with a suture. Brenneman suggests attaching a sling to the sutures such that when the sutures are pulled tight and knotted, the sling is urged towards the pubic bone. Benderev suggests integrally molding one end of a suture with a “suture support”, which suture support is provided to prevent damage to the urethra by the sutures. 
     It should be noted that, prior to the introduction of slings, some earlier procedures, for example the Burch procedure and the M.M.K. procedure, used only sutures without a sling to support the bladder neck. Also the, different, needle bladder neck suspension procedure uses only sutures. The disadvantage of these procedures is that the bare sutures can cut into and damage the urethra. In a sling procedure, described below, a mesh or a wide strip of material contacts the urethra instead of sutures, so that the urethra is not damaged. 
     FIG. 1 is a schematic side cut-through illustration of a pubic region  20  during such a procedure, before the sutures are tightened. In the figure, a sling  32  is located between a vagina  22  and a bladder neck  26  of a bladder  24 . The sling is threaded by a plurality of sutures  36 , which are attached to a bone anchor  30 , in a pubic bone  28 . 
     There are two commonly applied methods of bringing sling  32  to a position between vagina  22  and bladder neck  26 . In a first method, an incision is made in the vagina, at an area corresponding to that marked with reference number  34 , perpendicular to the figure plane, thereby forming a flap. The sling is inserted into the incision, under the flap, and after the sling is tightened, the incision is closed. In a second method, only a small hole in the vagina lining is made for each inserted bone anchor and a tunnel is formed between the two holes, for insertion of sling  32  therethrough. 
     This family of suture-sling techniques has several disadvantages: 
     (a) the suture is an additional element which may be damaged during the procedure or after it; 
     (b) knotting the sutures (after they are tightened) takes skill and time; additionally, some patients have complained that the sutures cause discomfort during sexual activity, since such sutures typically have sharp edges and are often bulky as the suture may have to be knotted as many as six times to assure patency; 
     (c) the sutures add some unwanted leeway between the positioning of the anchors and the positioning of the ends of the sling; and 
     (d) the sutures may damage the sling by cutting through it (older tissue being more susceptible); if the suture enters the sling at multiple points (to reduce strain at the sling-suture joints) the sling may be deformed by the sutures. 
     U.S. Pat. No. 3,580,313, to McKnight, the disclosure of which is incorporated herein by reference, suggests using the tissue between the urethra and the vagina as a “sling” and stapling that tissue to the pubic bone. However, this solution may not be suitable for some patients, such as older patients, as their tissue are usually too weak to provide a suitable support. Also, older tissue is more susceptible to cut-through damage from the staples. 
     SUMMARY OF THE INVENTION 
     An aspect of some preferred embodiments of the present invention relates to a sutureless method of supporting a bladder neck. In a preferred embodiment of the invention, the bladder neck is supported by a sling, and the sling is directly tacked to a pubic bone, without intermediate sutures. Alternatively or additionally, the sling is directly attached to the bone using other means, for example an adhesive. As used herein “directly attached” means attached without an intermediate suture. In many cases, the sling will not be in direct physical contact with the bone. Generally, but not necessarily, there will be only tissue (if any) between the sling and the bone. However, in a preferred embodiment of the invention, there will not be a suture or other implant between the sling and the bone. 
     It is noted that by not requiring sutures, the previously required step of tightening and tying the sutures is not required. 
     An aspect of some preferred embodiments of the invention relates to a sling that is preloaded with one or more tacks at one or both ends thereof prior to insertion into a body. In a preferred embodiment of the invention, the pre-loaded sling is mounted on a tacker, for insertion into the body. Alternatively, the sling is not provided as pre-mounted on a tack and is mounted on a tack only after the tack is mounted on a tacker with a protruding tack. Optionally, the mounting of the sling is a two step process, in which the tack is assembled after the sling is mounted on it. 
     An aspect of some preferred embodiments of the invention relates to tacks with wide heads. In a preferred embodiment of the invention, a tack comprises a shaft and a head, where the head has a maximum extent perpendicular to the shaft, which extent (the width of the head) is considerably greater the shaft diameter. Alternatively or additionally, the width of the head is made considerably greater than a maximum extent of a bone-entering portion of the tack (which is usually wider than the shaft). Thus, the head is larger than the hole formed in the sling by its being tacked and the head can maintain the sling in place. In a preferred embodiment of the invention, the head is substantially circular or polygonal. Alternatively, the head is a bar-shaped beam which is perpendicular to the shaft. As used herein “considerably larger” means 50%, 100%, 200%, 400% larger or more. Although the head may be large, it is not necessarily solid. Rather, one or more holes may be formed in the head. Optionally, these holes are used for threading the sling through them. 
     In some preferred embodiments of the invention the head can rotate relative to the shaft. 
     An aspect of some preferred embodiments of the invention relates to disassembled or deformable tacks, in which a sling may be pierced with a small diameter portion of the tack. The tack is then assembled or deformed, so that the head and/or bone entering portions of the tack have a larger diameter than the piercing portion. In one example, the tack comprises two parts, a head with a shaft portion and a bone-entering portion. The sling is pierced by the shaft portion and then the bone-entering portion is attached to a protruding end of the tack. In another embodiment, the bone-entering portion is maintained at a small diameter until after it pierces the sling, for example by a fin in the shaft receding into a recess formed in the shaft or by the shaft being expandable. In another example, the head is separate from the shaft. 
     An aspect of some preferred embodiments of the invention relates to an attachment to a bone stapler, which attachment holds a sling in place over a staple-exit portion of the stapler, to enable a standard stapler or a standard bone-anchor inserter to be used for tacking slings in accordance with a preferred embodiment of the invention. In a preferred embodiment of the invention, the type of stapler provided is such that the tip of the staple does not protrude from the stapler, so the sling is preferably maintained in place solely by the attachment. In an alternative embodiment, the tip of the staple does protrude from the stapler and may serve to at least partially hold the sling, while the attachment fixes the orientation of the sling relative to the staple or the attachment. If a two prong staple (or tack) is used, such an attachment may serve solely to keep the sling from slipping off the tip of the staple. 
     An aspect, of some preferred embodiments of the invention, relates to a tacker which includes two stapling heads, for simultaneous tacking of two sides of a sling. In a preferred embodiment of the invention, the tacker comprises two arms, with a tacking head at the end of each arm. Preferably the angle between the arms is controllable to adapt the tacker for different length slings. In a preferred embodiment of the invention, the sling is pre-mounted on the two heads prior to insertion into the body. 
     There is thus provided in accordance with a preferred embodiment of the invention, a surgical tack, comprising: 
     a single shaft formed of a bio-compatible material and having a tip adapted for entering and engaging bone; and 
     a head mounted on said shaft, said head adapted for engaging a substrate between said head and said bone. Preferably, said shaft is a separate element from said head. Preferably, said head is rotatable relative to said shaft. Alternatively or additionally, said head is mounted in a slot defined at an end of said shaft. Alternatively or additionally, said head is mounted on a narrowing of said shaft. 
     In a preferred embodiment of the invention, said head comprises only one arm extending substantially perpendicular to said shaft. 
     In a preferred embodiment of the invention, said head comprises at least two arms extending substantially perpendicular to said shaft. Alternatively, said head comprises at least one arm extending at an angle to said shaft. 
     In a preferred embodiment of the invention, said head defines a plurality of apertures therethrough. Alternatively or additionally, said head comprises a plurality of protrusions extending in a direction of said tip, which protrusions are adapted for engaging said substrate. Preferably, said protrusions are smooth at a portion thereof where they engage said substrate. Alternatively, said protrusions are pointed at a portion thereof where they engage said substrate. 
     In a preferred embodiment of the invention, said protrusions extend at least half a thickness of the substrate. 
     In a preferred embodiment of the invention, the tack comprises at least one fin extending from said shaft, distal from said head, and adapted for engaging said bone after insertion of said shaft into said bone. Preferably, said at least one fin comprises at least two angularly spaced apart fins. Alternatively or additionally, said at least one fin comprises at least two axially spaced apart fins. Alternatively or additionally, said at least one fin comprises a separate element from said shaft. Alternatively, said at least one fin is integrally formed with said shaft. 
     In a preferred embodiment of the invention, said shaft defines a recess and said at least one fin is adapted for recessing into said defined recess, when force having a vector perpendicular to said shaft is applied to said fin. 
     In a preferred embodiment of the invention, said at least one fin is mounted on a separate fin element, which is attached to said shaft. 
     In a preferred embodiment of the invention, said head is roughened at a portion thereof that engages said substrate. 
     In a preferred embodiment of the invention, said tack comprises an advance-stop on said shaft adjacent said head and separate from said head, such that said advance-stop prevents said head, at portions near said shaft, from touching said bone. Alternatively or additionally, said head has two configurations, one in which it has an substantially large transaxial extent and one in which it has a substantially small transaxial extent. 
     There is also provided in accordance with a preferred embodiment of the invention, a tack insertion device, comprising: 
     a “C” shaped body; 
     a handle at one end of said body; 
     a slotted tack holder at a second end of said body, wherein said slotted tack holder holds a tack pointed towards said handle and wherein said slot is adapted for frictionally engaging a tack. 
     Preferably, said slotted head is adapted to engage a tack having a multi-arm head. Alternatively or additionally, said slotted head is adapted to engage a tack having an apertured head. 
     In a preferred embodiment of the invention, said device comprises a second tack holder attached to said body at an offset from said first tack holder. Preferably, said device comprises a selectable offsetting mechanism for setting said offset. 
     In a preferred embodiment of the invention, said device comprises a safety release mechanism that prevents the release of said tack. 
     There is also provided in accordance with a preferred embodiment of the invention, a method of preparing a sling combination, comprising: 
     providing a sling formed of a biocompatible material and having two ends; 
     mounting said sling on a first tack at a first end of the sling; and 
     mounting said first tack on a tacking device. Preferably, said method comprises mounting said sling on a second tack at a second end of said sling. Preferably, said method comprises mounting said second tack on said tacking device. 
     In a preferred embodiment of the invention, said method comprises adjusting an offset between two tacking heads of said tacking device. 
     In a preferred embodiments of the invention, said method comprises cutting said sling after mounting said first tack on said sling. 
     In a preferred embodiment of the invention, mounting said sling on said first tack is performed after said tack is mounted on said tacking device. Alternatively, mounting said sling on said first tack is performed before said tack is mounted on said tacking device. 
     In a preferred embodiment of the invention, the method comprises assembling said first tack after mounting said sling on said first tack. Alternatively, the method comprises assembling said first tack after mounting said first tack on said tacking device. 
     Preferably, assembling said first tack comprises attaching a head to a shaft of said tack. Alternatively or additionally, assembling said first tack comprises attaching at least one fin to a shaft of said tack. 
     In a preferred embodiment of the invention, mounting said sling on said tack comprises piercing said sling by said tack. Alternatively, mounting said sling on said tack comprises inserting said tack into a hole in said sling. 
     In a preferred embodiment of the invention, the method comprises inserting at least a part of said tacking device into a human vagina, after mounting said tack on the tacking device. 
     There is also provided in accordance with a preferred embodiment of the invention, a kit, comprising: 
     a sling having a length suitable for bladder neck supporting; and 
     at least one tack, having a head and a shaft, wherein said head has an extent perpendicular to the shaft, which extent is substantially greater than a diameter of the shaft. Preferably, said sling contains at least one pre-punched aperture. Alternatively or additionally, said sling contains at least two adjacent pre-punched apertures, for setting an effective sling size. 
     In a preferred embodiment of the invention, said at least one tack comprises at least two tacks. Alternatively or additionally, said sling is reinforced at least at its ends. 
     There is also provided in accordance with a preferred embodiment of the invention, a kit, comprising: 
     a sling formed of bio-compatible material and having a length and mechanical properties suitable for bladder neck supporting; and 
     a clip adapted to hold said sling against a tacking head of at least a particular tacking or stapling device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more clearly understood from the following detailed description of the preferred embodiments of the invention and from the attached drawings, in which: 
     FIG. 1 is a schematic cut-through illustration of a pubic area during a prior art bladder neck support operation; 
     FIG. 2 is a schematic cut-through illustration of a pubic area during a bladder neck support operation, in accordance with a preferred embodiment of the invention; 
     FIG. 3 is a schematic illustration of a tack for attaching a sling to a bone, in accordance with a preferred embodiment of the invention; 
     FIG. 4 is a schematic illustration of a two part tack for attaching a sling to a bone, in accordance with a preferred embodiment of the invention; 
     FIG. 5 is a schematic illustration of a tacker for attaching the tack of FIG. 3; 
     FIG. 6 is a blow-up of a tacking head part of the tacker of FIG. 5; 
     FIG. 7 illustrates a tack which is preloaded on a sling and mounted on a tacker, in accordance with a preferred embodiment of the invention; 
     FIG. 8 is a schematic illustration of a two-headed tacker, in accordance with a preferred embodiment of the invention; 
     FIGS. 9A-9D illustrate an alternative tack, in accordance with a preferred embodiment of the invention; 
     FIG. 10, which corresponds to FIG. 6, illustrates the mounting of the tack of FIGS. 9A-9D on a tacker; 
     FIGS. 11A-11B illustrate a variation of the tack of FIGS. 9A-9D, in accordance with a preferred embodiment of the invention; 
     FIGS. 12A-12C illustrate variations of the head of a tack, in accordance with alternative preferred embodiments of the invention; 
     FIGS. 13A and 13B illustrate a recessed fin tack, in accordance with a preferred embodiment of the invention; 
     FIGS. 13C and 13D illustrate an expanding head tack, in accordance with a preferred embodiment of the invention; and 
     FIG. 14 is a schematic illustration of a sling grasping attachment for a stapler, in accordance with a preferred embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2 is a schematic cut-through illustration of a pubic area during a bladder neck support operation, in accordance with a preferred embodiment of the invention. A sling  40  is shown as being tacked directly to pubic bone  28 , by a tack  42  and being held in place by a head  44  of tack  42 . In a preferred embodiment of the invention, a shaft of tack  42  pierces sling  40 . Alternatively or additionally, the sling is held against the bone by friction, caused by head  44  urging sling  40  against pubic bone  28  (possibly through intervening tissue). 
     In a preferred embodiment of the invention, the following method is used to attach the sling to the bone: 
     (a) a first tack is tacked (preferably through sling  40 ) into a first location on pubic bone  28 ; 
     (b) the sling is inserted between vagina  22  and bladder neck  26  or the urethra: access is preferably via one or more incisions in the vaginal wall; 
     (c) a second tack is tacked through the sling and into a second location on the pubic bone; and 
     (d) any incisions in the vagina are preferably closed, e.g., sewn up. 
     The above method may be varied in accordance with various preferred embodiments of the invention. In particular, the order of steps may be changed and steps may be combined. In one example, the two tacks may be tacked simultaneously, using a two-headed tacker, as described for example with reference to FIG.  8 . 
     In a preferred embodiment of the invention, the sling comprises a strip of xenograft material. Alternatively or additionally, the sling comprises human cadaver tissue or auto-graft material harvested from the patient. Alternatively or additionally, the sling comprises a synthetic material, for example Dacron mesh. In a preferred embodiment of the invention, the sling is about 1 mm thick, 1-2 cm wide and 5.5 cm long, between the tacked points. It should be appreciated however, that the exact dimensions of the sling may vary responsive to the anatomy of the patient being treated. Possibly, a prior-art sling may be utilized. 
     In a preferred embodiment of the invention, the sling is reinforced at or near portions thereof through which the tack is inserted and/or portions of the sling engaged by head  44 . Alternatively, the sling is not reinforced. Alternatively or additionally, a hole is pre-punched in the sling at or near where the insertion point of the tack. Possibly, the hole is reinforced. The hole may have a shape similar to the cross-section of the shaft or it may be larger or smaller than the cross-section and/or of a different shape. In a preferred embodiment of the invention, one or more slits are formed (and optionally reinforced) in the sling at locations where the tack is to be inserted instead of—or in addition to—punching a hole thereat. Alternatively or additionally, an elliptical or a long rectangular slot may be cut in the strip to accommodate a plurality of tack positions. Alternatively or additionally, a plurality of pre-punched holes and/or pre-cut slits maybe provided for that purpose. Excess sling length is optionally removed either prior to or after deployment of the sling. Alternatively or additionally, the sling is formed of two parts, that are glued together to form a sling of a desired length, prior to or after being tacked to the bone. 
     In a preferred embodiment of the invention, human cadaver based slings do not have pre-provided holes, while synthetic slings do. In some cases, holes are cut just prior to the procedure. Alternatively, the holes are cut in a factory. 
     In a preferred embodiment of the invention, the sling has a smooth surface. Additionally or alternatively, at least one of the two surfaces of the sling is rough, for example to promote tissue ingrowth. Additionally or alternatively, the sling is coated with tissue growth enhancing or retarding coatings, possibly both, on different parts of the sling. Additionally or alternatively, the sling may have a plurality of barbs, apertures and/or other structures defined thereon to grasp soft tissue, for example the urethra and/or tissue between the urethra and the bone. 
     In a preferred embodiment of the invention, the sling is pre-loaded on one or both tacks, before the tacking head is inserted into the body. The pre-loading may be performed in a factory or a work shop, where the sling is produced and/or processed. Alternatively, the pre-loading is performed at the operating table, possibly after a desired sling length is determined 
     Alternatively, the sling is placed between the tacking head and the bone, inside the body, so that the inserted tack will pass engage the sling before entering the bone. In an exemplary embodiment, one tack is pre-mounted on the sling and is inserted into the bone. The sling is then stretched using a forceps, for example, and a second tack is inserted through the sling into the bone. 
     In a preferred embodiment of the invention, only two tacks are used, one for each side of the sling. Alternatively, more than two tacks may be used for example, for a wide sling (e.g., two tacks on at least on side of the sling), for an “X” shaped sling or to adjust the length of slings which are not tight enough. In some embodiments, one side is tacked and the other side is sutured or otherwise attached, for example to assist in adjustment. Alternatively, the two ends of the sling may be tacked together at a single point on pubic bone  28 , possibly using a single tack, thereby forming a closed loop of the sling. Preferably, that single point is not at the center of the pubic bone. 
     In a preferred embodiment of the invention, a sling is used to support the bladder neck. Alternatively, such a sling may be provided to support the bladder itself, the urethra and/or other abdominal organs. Bladder support, also known as cystocelle repair, generally requires a wide sling with a plurality of tacks at each end (or wide tacks). Also, such a sling may be used to correct a defect in the abdominal floor from which internal organs protrude, by supporting or suspending such organs. Alternatively or additionally, such a sling may be used for male bladder, urethra or bladder neck suspension. Alternatively or additionally, such a sling may be used for a tongue suspension and/or for suspending other soft tissues in the body. 
     In a preferred embodiment of the invention, a catheter is inserted into the urethra prior to the procedure, to minimize the risk of accidentally puncturing the urethra. Additionally, such a catheter may be useful when determining a desired sling length. 
     In a preferred embodiment of the invention, a flap-forming incision (e.g., at location  34 ) is made in the vagina prior to the first tacking or between the first and second tacking, so that the sling can be brought through the incision, under the flap and into the tissue between the vagina and the urethra. Alternatively, both tacks are tacked (with at least part of the sling still inside the vagina) and then the incision is made in the vagina. In some circumstances, no incision will be made and a significant portion of the sling will remain in the vagina 
     Alternatively to making an incision in the vagina, a sub-mucosal tunnel may be formed in the tissue between the vagina and the urethra and the sling and/or a tacker device (described below) passed through the tunnel. In a preferred embodiment of the invention, only a single incision is made and the tunnel is made through that incision, for example using an endoscope. Alternatively, two incisions are made and the tunnel formed between them. As described herein, such tunneling preferably utilizes small incisions in the vagina which are either formed by the tacks passing through the vaginal wall to the bone or prepared in advance for the tacks. The tunneling and/or passing may be performed before the first tacking or between the first tacking and the second tacking. When using a tack where the sling is attached to the tack after the tack is inserted into the bone (described below), such tunneling may even be performed after both tacks are attached to the bone. 
     In a preferred embodiment of the invention, a small incision and/or hole is made in the vagina for the insertion of each tack. Optionally, tissue which intervenes between the vagina and the pubic bone is moved away from the path of the tack so that the tack compresses only a minimal amount of living tissue (other than the sling) against the pubic bone. Alternatively, the tack may create its own hole in the vaginal wall. As described above, these holes/incisions may be used as an aid to forming a sub-mucosal tunnel which bridges the incisions and is between the vagina and the urethra. In some embodiments of the invention, when a tack is tacked to a bone through the hole, a portion of the sling is pulled, by the tack, out of the vagina and into the hole. In an embodiment where only a single incision is made, both tacks (or only a single one if the tacking is at a single location only) are brought through the same, small, incision. 
     The tacks are preferably attached to the superior pubis ramus (as shown in the figure). Thus, the sling is angled forward (when the patient is standing). If the bladder neck or the urethra descend suddenly, the neck is then held up by the sling. Alternatively, the tacks may be attached to other parts of the pubic bone, for example its bottom or its front, as the tacks may have a flat head which does not cause contact discomfort. Additionally or alternatively, especially for bladder neck suspension procedures, it may be desirable to tack the tacks higher up on the bone or even on the abdominal fascia. 
     In a preferred embodiment of the invention, the length of the sling is determined prior to the tacking. Alternatively, after the first tack is inserted, a required sling length may be determined and the sling cut to size. Optionally, any trailing portions of the sling which remain after the tacking are cut off. 
     FIG. 3 is a schematic illustration of a tack  50  for attaching a sling to a bone, in accordance with a preferred embodiment of the invention. Tack  50  includes a sharp tip  52  for entering the bone, a shaft  54  which grasps the sling and a head  56  for preventing the sling from slipping off the shaft and/or for urging the sling against the bone, to prevent relative movement of the sling and the bone. One or more fins  58  may be provided to improve the bone holding characteristics, however, they do generally interfere with insertion into bone. In some embodiments, fins  58  are flexible. In other embodiments, they are rigid. Alternatively, other constructions for bone piercing and grasping tips, as known in the art, may be used, for example screw-tipped inserts. In a preferred embodiment of the invention, head  56  comprises a pair of extending arms  57 . At the tip of each arm (or elsewhere along their length) a protrusion  59  is preferably provided. As will be shown below, sling  40  is preferably urged by protrusions  59  against the bone, however, the entire head may do the urging. Protrusions  59  are preferably flat at their contact point with sling  40 . Alternatively, they may be pointed or roughened. Possibly, holes are formed in sling  40  (prior to, during or after insertion), so that at least some of the protrusions  59  transfix sling  40  through these holes. Head  56  is preferably flat, however, in some embodiments it may protrude, especially for covering up sharp angles in the head. 
     In a preferred embodiment of the invention, the arms are perpendicular to the shaft. Alternatively, they may be angled, towards the tip or away from the tip, for example, 10°, 20°, 30° or 45° away from a perpendicular to the shaft. Thus, the tips of the arms can mimic the behavior of protrusions  59 . Preferably the arms are super elastic, however, they can also function correctly if they are elastic, plastic or shape memory. The arms may be in the plane of the shaft or outside of the shaft place, possibly not parallel to the shaft plane. 
     In a preferred embodiment of the invention, a head  56  is wide, for example a circular plate, a sphere or a half-sphere. In some embodiments, the wide head comprises an expanding head, which, once the tack exits the tacker, expands and/or unfolds to have a wide extent. Preferably, the folded/unexpanded head has a diameter similar to that of the shaft, so that the tack is suitable for use in existing anchor insertion devices. In one example, the unfolding head comprises a super-elastic material which is maintained at a deformed (small head diameter) configuration by the tacker. In another example, the expanding head is expanded as a result of pressures applied during the insertion into the bone, for example pressure applied by an anvil portion of the tacker which forces the tack into the bone (described below). 
     One possible disadvantage of the tack of FIG. 3 is that the diameter of the shaft is smaller than the diameter of the tip. Thus, when the sling is loaded onto the tack, the tip may rip a larger-than-necessary hole in the sling. In some cases, the sling is sufficiently flexible and/or elastic to accommodate the tip. 
     In a preferred embodiment of the invention, it may be desirable to provide a two part tack, such as tack shown in FIG. 4 as a tack  60 , in which a head  66  and a shaft  62  form a first portion, having a small diameter and on which the sling is skewered. Once the sling is skewered by shaft  62 , a bone engagement portion  64  is mounted on shaft  62 , to form a complete tack  60 . The end result is thus a tack on which a sling, with only a small hole therethough, is loaded. In some embodiments, head  66  is separate from shaft  62 . complete tack  60 . 
     Alternatively to using a dedicated tack, a commonly available staple, for example a “U” type staple may also be used to tack the sling to the pubic bone. Thus, the tack may have two or more legs that engage the bone. Possibly however, the quality of the attachment is lower. For example, there may be an increased strain on the sling. 
     Possibly, the sling is not pierced by the tack at all. Rather the sling is provided between the two or more shafts of the tack (or legs of a staple) and is urged against the bone by the head of the tack and held thereat by friction. Preferably, the portion of the head of the tack that engages the sling is rough or jagged, to better grasp the sling. Additionally or alternatively, a stop is provided on the one or more legs, so that a minimal space is provided between the bone and the head of the tack, for example to prevent undue compression of intervening soft tissue. Additionally or alternatively, the sling may be captured between the shaft and the bone, for example, the shaft has a depression formed in its side and the sling is held between the depression and the portion of the bone which is inside the hole made by the tack. Alternatively or additionally, the sling may be held by holes in the head of the tack (described below). 
     Additionally or alternatively to using a tack, some preferred embodiments of the invention contemplate other methods of attaching the sling directly to the bone, for example using a quick setting adhesive. 
     In a preferred embodiment of the invention, once the tack is inserted into the bone, the sling is firmly attached to the bone. In some embodiments of the invention, however, the sling may be fixed to the tack after the tack is attached to the bone. In one example, similar to that of FIG. 4, a thin-headed tack is attached to the bone and only then is the sling loaded onto the tack. Thereafter, the head of the tack is attached and/or expanded, to snugly grasp the sling. 
     In a preferred embodiment of the invention, a guiding wire or suture is attached to the tack, so that the sling can be guided along the guide wire to the tack, for properly engaging it with the tack head. This wire may then be removed from the tack, as it is does not structurally interconnect the tack and the sling. This embodiment is useful for example if the exact length of the sling is not known in advance. Preferably, the sling has a plurality of holes formed therein, to engage the shaft of the headless tack at various positions along the sling. 
     FIG. 5 is a schematic illustration of a tacker  70  for attaching the tack  50  of FIG. 3 to pubic bone  28 . Tacker  70  preferably comprises a handle  72 , a body  74 , which is preferably curved and adapted for use in the vagina and a head  76 , which is urged against the pubic bone for inserting a tack. In this embodiment, a tack  50  is mounted at least partially externally to the head. In other embodiments, the tack may be partially or completely recessed inside head  76 . Alternatively or additionally, a flexible protecting cover is provided, which cover is pushed back from the tip of the tack to the direction of the head of the tack, by the bone when the tack is pressed against the bone. In a preferred embodiment of the invention, a cartridge of such tacks is attached to head  76  or enclosed in body  74 . 
     In a preferred embodiment of the invention, tack  50  is held onto head  76  by friction, such that, once it is engaged by the bone it can be removed from head  76 . Alternatively, a release mechanism (not shown) for preventing the release of the tack may be provided. Alternatively or additionally, such a release mechanism may prevent the tops of fins  58  from exiting the tacker, so that the tack cannot be irrevocably attached to the bone, without activating the mechanism. Preferably, force is applied to the tack by pulling up handle  72 , thereby directly pulling back tack  50  into the bone. Alternatively, tacker  70  may include a mechanism for advancing tack  50  into the bone, for example a lever based mechanism or a pneumatic mechanism. In devices with a release or a safety mechanism, the mechanism is preferably released prior to applying the force or during the force application, for example by a lever on handle  72  (not shown). 
     FIG. 6 is a blow-up of tacking head  76  part of the tacker  70  of FIG. 5. A slot  71  is preferably formed in head  76 , to hold arms  57  for the tack configuration shown. 
     FIG. 7 illustrates a tack  50 , preloaded on a sling  40  and preloaded on the tacker, in accordance with a preferred embodiment of the invention. 
     FIG. 8 is a schematic illustration of a two-headed tacker  80 , in accordance with a preferred embodiment of the invention. Tacker  80  includes two arms, an arm  82  and an arm  84 , each with a tacking head,  86  and  88 , respectively. In a preferred embodiment of the invention, the distance between the tacking heads may be controlled using a screw  90 . Screw  90  may set a maximum and/or minimum distance between the tack heads or it may fix the distance between the tack heads. In one embodiment of the invention, the sling is preloaded on the tacks on the two tacking heads, the two heads are placed in the vagina and the two tacks are simultaneously tacked into the pubic bone. An incision for bringing the sling outside the vagina may be made before or after the tacking. Alternatively, the sling is first brought into the desired area between the vagina and the urethra, possibly using a tunnel and then the sling is loaded (or not) onto the tacks and the tacks are attached to the bone. 
     In a preferred embodiment of the invention, tacker  80  includes only a single handle  92 , which utilizes a single mechanism for advancing both tacks (if such mechanism is provided). Alternatively, the handle includes two separate mechanisms. Alternatively, also a second handle  93  is provided. Each of handles  92  and  93  may have a separate mechanism. 
     Alternatively to attaching the tacks substantially simultaneously, the tacker may be used to attach the tacks in series, first one and then the other. Optionally, screw  90  includes a sliding mechanism for allowing only one of the two handles to be retracted at a time without also advancing the tack of the other handle. In a preferred embodiment of the invention, setting screw  90  supports fixing the length of the sling outside the body, by setting the distance between the tacking heads (and thus, typically, the tacks). 
     FIGS. 9A-9D illustrate an alternative tack  100 , in accordance with a preferred embodiment of the invention. FIG. 9A is a perspective view of tack  100 , showing a tip  102  of a shaft  104 , two fins  108  and a head  106 , connected to shaft  104  by crimping an extension  112  of shaft  104  to engage a ring portion  110  of head  106 . In a preferred embodiment of the invention, head  106  comprises two arms  107 , having one or more apertures  105  formed therein. A protrusion  109 , preferably wedge shaped, is provided at the end of each arm  107 . 
     In a preferred embodiment of the invention, such slings are provided pre-sutured. In a preferred embodiment of the invention, the sutures are in the form of a loop (through which shaft  106  is preferably passed). Such a loop are preferably shortened by knotting, if needed. Alternatively, the sutures are not looped. Such pre-sutured slings may also be used for prior art sling procedures. 
     FIG. 9B is a top view of tack  100 . 
     FIG. 9C is a side view along the direction of line B—B (FIG. 9B) of tack  100 . 
     FIG. 9D is a cross-section along line B—B (FIG. 9B) illustrating the crimping of extension  112  over ring  110 . In a preferred embodiment of the invention, bead  106  is thus free to rotate relative to shaft  104 , however, this freedom is not essential in all embodiments and may even be explicitly blocked, for example by forming a notch in ring  110 . 
     FIG. 10, which corresponds to FIG. 6, illustrates the mounting on a tacker  120  of tack  100 . A slot  122  formed in the head of tacker  120  is preferably configured so the head fits in apertures  105 , by slot  122  matching a pair of arms  124  that extend between ring  110  and the rest of head  106 . 
     FIGS. 11A-13B illustrate variations in tack designs. 
     FIG. 11A is a top view of a tack  130  having four arms  132  (rather than two). Alternatively, other numbers of arms, for example three may be provided. Arms  132  are preferably symmetrically arranged and all of a same length, however, this is not essential and in some embodiments one arm may be shorter or two arms may be closer together than the other arms. 
     FIG. 11B is a cross-sectional view of a tack  140 , corresponding to FIG.  9 D and showing an alternative method of attaching a head  142  to a shaft  144 , for any type of tack, in which a slot  146  is formed in shaft  144 , to receive head  142 . An advantage of this method is that an incorrectly placed tack may be corrected by removing the head and advancing the shaft so it is completely enclosed by the bone. In a preferred embodiment of the invention, the head is super-elastic or elastic, so that by applying enough force it can be mounted on the shaft or removed, without permanently distorting it. Alternatively, one time elastic or plastic heads are used, alternatively, a shape-memory material may be used. 
     FIGS. 12A-12C illustrates variations of head portions of tacks. FIG. 12A illustrates ahead  150  which defines a plurality of apertures  152  therein and has a plurality of protrusions  156  around its perimeter (and also possibly inside the perimeter), which protrude towards the bone. Central aperture  154  is preferably used to affix head  150  to a shaft of a tack. The apertures may or may not be aligned with the protrusions that most forcefully engage the sling. 
     FIG. 12B illustrates, in top view, a tack  160 , which comprises spiral arms  162 , rather than straight arms as described above. An advantage of spiral arms is an increased flexibility of the arms, without compromising their strength. A pair of fins  164  are also shown, for example of the type used in device  100  of FIG.  9 . 
     FIG. 12C illustrates, in top view, a tack  170 , which has only a single arm  174 . A pair of fins  174  is also shown, perpendicular to the arm. Alternatively, the fins are parallel or oblique to the arm. Alternatively, only one fin  174 , preferably opposite arm  172 , is used. 
     FIGS. 13A and 13B illustrate a recessed fin tack  180 , in accordance with a preferred embodiment of the invention. Tack  180  comprises a head  190  attached to a shaft  182  with a tip  184 . At least one fin  186 , but possibly more than one, extend from shaft  182 , as shown in FIG.  13 A. In a preferred embodiment of the invention, a recess  188  is formed in shaft  182 , to receive fin  182  during insertion into the bone, so fin  186  does not impede the insertion process (FIG.  13 B). Preferably, during insertion, the edge of the bone presses fin  182  into recess  188 . In a preferred embodiment of the invention, shaft  182  or fin  186  is formed of an elastic, shape-memory or super-elastic material, to assure that fin  186  returns to an extended configuration as shown in FIG.  13 A. 
     FIGS. 13C and 13D illustrate an expanding head tack  200 , in accordance with a preferred embodiment of the invention. Tack  200  comprises a shaft  202 , preferably with a plurality of fins  206  at its tips. The head of tack  200  comprises two distortable parts  210 . As shown, two or more separate arms are provided, possibly each one with a protrusion as in some of the previous embodiments. Alternatively, an extension of shaft  202  may be split. When the tack is inserted the head may be narrow, as shown in FIG.  13 C. When the tack is inserted into a bone, the head is split, for example using a cone shaped element  212 , resulting in a tack as shown in FIG. 13D, which can be substantially the same as the tack of FIG.  3 . In a preferred embodiment of the invention, an advance-stop  208  is provided, to prevent shaft  202  from advancing too far, especially while portions  210  are being split apart. Such a stop may also be provided in other tack design, for example to provide a minimum distance between the head and the bone. Alternatively, the advance stop is part of the tacking head, for example being in the form of forceps or a “C” shaped element which space the head from the bone and is removed with the tacking head. Possibly, the advance stop is formed of an bio-absorbable material. 
     In a preferred embodiment of the invention, advance-stop  208  extends away from shaft  202 , at least in one transaxial direction, more than portions  210  in their unexpanded configuration. In a preferred embodiment of the invention, a slotted insertion device pushes against advance-stop  208  and an additional internal mandrel is provided to serve as element  212 . Thus, portions  210  are distorted plastically. Alternatively, the portions may be formed of a shape-memory material (which can be optionally heated by the tacking head). Alternatively, the portions may be elastic or super-elastic. Preferably, the portions are maintained in their narrow configuration by the slotting head, which, when removed, allow them to snap open to their wide configuration. Alternatively or additionally, a bi-stable or a bimetal-mechanism for configuration change may be used. Such elastic, plastic, shape-memory, super-elastic or other head distorting mechanism may be used with any of the tack-heads described above. 
     Additional variations in tack design are also contemplated in accordance with preferred embodiments of the invention. For example, the shaft of the tack may have a fixed or a varying profile, which can be, for example, circular, square, rectangular, triangular, fluted and/or spiral. Also, the shaft may be barbed and/or roughened. The tip of the tack may be, for example, smooth, fluted, threaded, spiral, inclined on some sides and flat on the others. Alternatively or additionally, the tip may be oblique, for example as shown in FIG.  13 . The fins may be, for example, of a design that is rigid or that folds back towards the shaft during insertion. The arms of the head may be, for example, perpendicular to the shaft or they may be slanted. Possibly, the arm configuration is designed to match a anatomical geometry, such as a bone incline. The fins may be distributed with a rotational symmetry around the shaft axis. Alternatively, they are not. Alternatively or additionally, the fins are all at a same axial position along the shaft. In some embodiments, they are not. 
     FIG. 14 is a schematic illustration of a sling grasping attachment  904  for a stapler  900 , in accordance with a preferred embodiment of the invention. As described above, in some cases, even a standard type staple, bone anchor and/or bone screw may be used to attach sling  40  directly to the bone. Such screws and staples usually include a stop for limiting the penetration depth into the bone, which can serve as a tack “head”, in accordance with a preferred embodiment of the invention. The portion of a shaft behind the stop, including for example a threadable hole, may be filed off, especially if they are not required for the structural integrity of the bone insert. However, the standardized staplers, anchor insertion devices and other bone attachment apparatus do not appear to provide for a sling that is engaged by the staple. Attachment  904 , is an example of an attachment which maintains the sling in a desired position and/or orientation relative to the staple, until the staple is inserted into the bone. In this embodiment, attachment  904  comprises a resilient clip that urges and holds the sling against the body of stapler  900 . In other embodiments, the attachment may be mounted over the tacking head, possibly extending the head length. In some cases, for example as shown, a staple  906  may pierce the sling, prior to the act of stapling. In other cases, the tip of the staple is recessed in the stapler and cannot engage the sling. In other embodiments of the invention, other attachments may be provided. In particular, the exact geometry of the attachment may be adapted for a particular stapler model and/or staple type. 
     In a preferred embodiment of the invention, the above described slings and tacks are provided as a kit which includes one or more slings of possibly varying lengths and two or more tacks. 
     Although the above description has focused on female urinary incontinence, a same procedure and apparatus may be used for male incontinence, for example, by attaching the sling to a descending ramous of the pubic bone through an incision in the perineal area. 
     It will be appreciated that the above described apparatus and methods of incontinence treatment may be varied in many ways. In addition, a multiplicity of various features, both of methods and of devices, have been described. It should be appreciated that different features may be combined in different ways. In particular, not all the features shown above in a particular embodiment are necessary in every similar preferred embodiment of the invention. Further, combinations of the above features are also considered to be within the scope of some preferred embodiments of the invention. It should also be appreciated that many of the embodiments are described only as methods or only as apparatus. The scope of the invention also covers machines for creating the devices. In addition, the scope of the invention includes methods of using, constructing, calibrating and/or maintaining the apparatus described herein. When used in the following claims, the terms “comprises”, “comprising”, “includes”, “including” or the like means “including but not limited to”.