Abstract:
Provided is an implantable sling for supporting a body organ. The sling may be used, for example, as a urethral sling, a puborectal sling or a surgical mesh for pelvic organ prolapsed repair. The sling of the invention has a first sling element, having a first sling body and two or more slender first projections extending from the first sling body. The sling may further include a second sling element having a second sling body and two or more slender second projections extending from the second sling body, and one or more detachable connections connecting the first sling element and the second sling element. In some embodiments, the connections are configured to tear when the first and second sling elements are pulled apart.

Description:
PRIORITY INFORMATION 
     The present application claims priority as a national stage entry of International Application No: PCT/IL2013/050973, filed on Nov. 26, 2013. The present application also claims priority from U.S. Provisional Patent Application No. 61/729,825, filed on Nov. 26, 2012. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a removable sling for use in the treatment of various conditions such as urinary stress incontinence, fecal incontinence and pelvic organ prolapse. 
     BACKGROUND OF THE INVENTION 
     Stress urinary incontinence (SUI) is the unintentional urine leakage during times of abdominal stress, such as occurs during coughing, laughing, or sneezing. One cause of SUI is inadequate anatomical support of the urethra which allows the urethra to move out of the retropubic space and rotate into the vagina. This condition is known as “hypermobility of the urethra” or simply “hypermobility”. SUI may also result from insufficient closing pressure of the urethra which prevents the urethra from fully collapsing and sealing. SUI can develop in men as a result of prostate surgery during which the voluntary sphincter mechanism is damaged either partially or totally. 
     Another medical condition suffered by women is pelvic organ prolapse (POP) which refers to prolapse of the organs (urinary bladder, intestines and uterus) normally positioned within the pelvis. Normally these organs are supported by the “pelvic floor”. Weakening of the pelvic floor allows herniation of these organs towards the vagina. 
     Another medical condition is fecal incontinence which is the inability to control bowel movements, causing feces to leak unexpectedly from the rectum. It may be due to a weakened anal sphincter associated with aging or to damaged nerves and muscles of the rectum and anus that can occur during childbirth. 
     Urethral slings have been used to treat hypermobility in women and postoperative incontinence in men. A urethral sling is typically implanted below the urethra to provide support under the urethra and prevent unwanted movement of the urethra towards the vagina or compress the male bulbous urethra. A variety of different slings have been developed that are implanted below the urethra to support it. In women, these slings are generally not intended to raise the urethra but to provide support for the urethra to prevent the unwanted downward urethral movement associated with hypermobility. A typical urethral sling comprises a strip of mesh that is implanted using a transvaginal approach in which opposite ends of the mesh are arranged on opposite sides (towards the sides or upwards) of the urethra so that the mesh loops under the urethra to form a sling. The mesh is typically implanted using needles that attach to the mesh of the sling so that the mesh ends can be inserted into the body and exit out of the body at a desired exit site and then are either anchored to the pubic bones or tissues, left under the skin, or in the periurethral or perivaginal space for self anchoring by tissue proliferation. Excess mesh extending out of the body can be removed and the remainder of the mesh left under the skin. During the first days after its implantation the unanchored sling is held in place by friction, then by tissue ingrowth through the interstices of the mesh. 
     POP can be repaired either by applying sutures to the pelvic floor to reshape the vagina and return the prolapsed organ to their normal position or by placing a layer of mesh to support the prolapsed organs. Surgery either through the vagina or through the abdomen (either open or laparoscopic) is the usual method of POP repair. 
     Fecal incontinence is treated by sphincteroplasty. Patients who are not suitable for such surgery or who have failed sphincteroplasty can be implanted a puborectal sling. 
     Mesh slings are generally successful in treating incontinence or POP but occasionally fail. One cause of failure is improper positioning of the sling, insufficient or excessive tension of the sling during implantation and dislocation of the sling sometime after implantation. Some of the complications which may develop after mesh implantation include failure of the sling to prevent incontinence, postoperative urine retention, sling caused bladder hyperactivity, coital pain, sexual impairment and/or discomfort, infection, vaginal and urethral tissue erosion. In some of these complications there may be an indication to remove the mesh sling. After tissue ingrowth into the spaces of the mesh, complete removal of the implanted mesh is very difficult. During the surgery or immediately after or within the first days after a mesh sling implantation, adjustment of a misplaced mesh sling can only be performed by pulling on the ends of the sling to increase the sling tension or releasing the tension through a vaginal incision. The extent of tension readjustement is limited even after a couple of weeks due to the tissue ingrowth and may not allow proper positioning of the mesh. Mesh slings do not allow late removal by simple surgery. 
     Some of the currently available mesh slings allow readjustment only after a few days following their implantation. United States Patent Publication 20080269547 to Hortenstine discloses an adjustable urethral mesh sling having an expansion chamber that is positioned under the urethra after implantation. A conduit in fluid communication with the expansion chamber allows remote expansion of the expansion chamber. The expanded chamber presses on the urethra and contributes to the closure of the urethral lumen during stress. 
     Any foreign body placed in a living tissue can elicit an inflammatory reaction in the surrounding tissue. This process is usually followed by gradual development of a cocoon-like collagen shell and/or fibrous tissue as a natural barrier around the foreign body (encapsulation). Mature cross-linked collagen and other extracellular matrix proteins gradually contribute to the formation of a hypocellular dense fibrous capsule that becomes impermeable or hypopermeable to many compounds. All soft-tissue implanted devices cause such a reaction. Since non-absorbable and biocompatible, smooth surfaced implants are unaffected by the biological activities of the surrounding tissues during the encapsulation process, they do not adhere to tissues and can be pulled-out easily at anytime. i.e. smooth surfaced monofilament surgical sutures remain within a smooth surfaced capsule and they can be pulled out at anytime much easily than a comparable multifilament braided sutures that are invaded by tissue. Other factors influencing the host response include implant location, size, shape, micromotion, surface chemistry, surface roughness, and porosity. (Dee K C, Puleo D A, Bizios R.  Wound healing. In: An introduction to tissue - biomaterial interactions . Hoboken, N.J.: John Wiley &amp; Sons Inc.; 2002). The process of capsule formation, as well as the structure of the final capsule, is similar in animal models and in humans. (Parker J A, Walboomers X F, Von den Hoff J W, Maltha J C, Jansen J A Soft-tissue response to silicone and poly-L-lactic acid implants with a periodic or random surface micropattern.  J Biomed Mater Res.  2002; 61:91-98). 
     SUMMARY OF THE INVENTION 
     The present invention provides a medical sling that may be used, for example, as a urethral sling, a puborectal sling or a surgical mesh for POP repair. 
     The sling of the invention comprises a first sling element and a second sling element. A first set of one or more finger like projections extend from an end of the first sling element, and a second set of one or more finger line projections extend from an end of the second sling element. The first and second sling elements are integral with each other by means of a plurality of connections between the finger like projections of the sling elements that are configured to allow the first and second sling elements to separate from each other when the first and second sling elements are pulled apart. This allows the sling to be removed from the body. The sling may be removed, for example, in cases of failure of the sling to prevent incontinence, postoperative urine retention, sling caused bladder hyperactivity, coital pain, sexual impairment, discomfort, infection, vaginal and urethral tissue erosion. 
     The sling of the invention may be embedded between two layers of biodegradable and/or bioabsorbable mesh to facilitate fixation of the sling. The biodegradable mesh allows tissue ingrowth through its interstices and fixes the sling during the first weeks after its implantation. The mesh then disintegrates allowing the tissue to enter the longitudinal spaces along the fingers of the sling. 
     The sling of the invention may be made from a biostable or biodegradable polymeric material that is inelastic, soft flexible, and biocompatible. The sling material may be reinforced by a mesh or filaments embedded into a polymer. The sling may be made from a bio stable knitted or woven material that can be unraveled, or from a yarn imbedded in a smooth biostable polymer layers. The knitted material or yarns may be tightly knitted or woven with a porosity below the size of living cells to prevent tissue ingrowth into the material. 
     The sling of the invention may be inflatable, in which case one or both of the first and second sling elements is made from a fluid impervious material and is provided with 1 or 2 ports through which an inflation material is introduced into an interior of the sling element. The inflation material may be, for example, sterile saline. 
     The sling of the invention may be introduced into the body through midline vaginal incisions under the urethra and then each end of the sling is directed through its ipsilateral obturator foramine before exiting the body through a skin incision. The sling ends can have mesh-like segments for self fixation. If a trans-obturator approach is used, the mesh ends should be over the obturator fascia. If an abdominal approach is used the mesh ends should be over the rectus fascia, where the mesh tips can be reached easily to be disconnected from the removable sling, in case the sling has to be removed. 
     For an inflatable sling, the sling is inflated after insertion and the ports of the sling may remain beneath the skin at the level of the obturator foraminae or under the skin at the suprapubic level after implantation. At any time, the amount of inflation fluid inside the inflatable elements can be changed in order to readjust the sling tension when it is determined that the urethra is not supported in a desired manner. 
     When implanted, the sling of the invention may become encapsulated by fibrotic scar tissue. The sling of the invention may have a smooth outer surface which tens to prevent invasion by the surrounding tissue. Spacing between adjacent finger-like projections in the sling allows vascularization of the tissues covering the sling. After encapsulation by collagen, the sling may be removed from the body, leaving behind the encapsulation tissue which may function as an autologous sling. 
     At any time after implantation, the sling may be removed from the body. For removal, the first and second sling elements are detached from each other. In some embodiments, this is accomplished by grasping the ends of the first and second sling elements and simultaneously pulling the first and second sling elements apart causing the connections between the first and second sling elements to be broken. As the two sling elements continue to be pulled apart, the sling elements become separated as they are removed from the body. In other embodiments, fingers in one sling element are stitched to the other sling element by a filament. In these embodiments, the first and second sling elements are detached from each other by removing the filament, and then the two sling elements can be separated from each other by pulling the two sling elements apart. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIGS. 1 a  to 1 f    show urethral slings in accordance with four embodiments of the invention; 
         FIG. 2  shows a cutaway view of an inflation port; 
         FIG. 3  shows details of an inflation finger in accordance with the present invention; 
         FIGS. 4 a  to 4 e    show urethral slings in accordance with yet another embodiment of the invention; 
         FIG. 5  shows a snap-fit attachment between layers of the sling of  FIG. 13 ; 
         FIGS. 6 a  and 6 b    show a woven sling in accordance with one embodiment of the invention; 
         FIG. 7 a    shows the sling of  FIG. 1 a    after implantation in the body using the trans-obturator approach; 
         FIG. 7 b    shows the pubourethral sling of  FIG. 1 a    after implantation in the body either using the trans-abdominal or trans-vaginal approach (the sling becomes U-shaped); 
         FIG. 7 c    shows the sling of  FIG. 1 a    used as a puborectal sling; 
         FIG. 8  shows a unidirectional inflatable sling in accordance with another embodiment of the invention; 
         FIG. 9  shows a bidirectional sling in accordance with yet another embodiment of the invention; 
         FIG. 10  shows detail of an inflation finger of the sling of  FIG. 5 or 6 ; 
         FIG. 11  shows detail of an inflation port of the sling of  FIG. 5 or 6 ; 
         FIG. 12  shows a sling of the invention placed between two layers of biodegradable and/or bioabsorbable mesh; 
         FIG. 13  shows a multilayerd mesh for use in Pelvic Organ Prolapse (POP); 
         FIG. 14  shows a snap-fit attachment between layers of the sling of  FIG. 13 ; 
         FIG. 15  shows a system for muscle stimulation for use in the sling of the invention; and 
         FIGS. 16 and 17  show attachment of sling parts with a monofilament wire. 
     
    
    
     DESCRIPTION OF THE INVENTION 
       FIGS. 1 a  to 1 f    show slings  2   a  to  2   f , respectively, in accordance with various embodiments of the invention. The slings  2   a  to  2   f  comprise a first sling element  4   a  to  4   f , respectively, and a second sling element  6   a  to  6   f , respectively. The first sling element  4   a  to  4   f  is provided with one or more slender finger-like projections  9   a  to  9   f , respectively. The second sling element  6   a  to  6   f  is provided with one or more slender finger-like projections  19   a  to  19   f , respectively. The slings  2   a  to  2   f  differ in the number and lengths of the finger-like projections. Thus, for example, in the sling  2   a , three finger-like projections are shown on each of the elements  4   a  and  6   a . This is by way of example only, and each element can have any number of finger-like projections as required in any application. The number of projections on the two elements may be the same, or may be different. 
     The first and second sling elements are integral with each other by means of a plurality of constrictions  12 . The constrictions  12  are weak points in the sling and are configured to when the first and second sling elements are pulled apart, as explained below. 
     The slings of the invention can be made of a single layer material (non-inflatable) or double-layered (inflatable). Both the single layer and the double layer slings can be reinforced by a mesh or filaments embedded into a polymer. The slings  2   a  to  2   b  are made from a fluid impervious, biocompatible material such as silicone. The material of the slings is preferably inelastic, soft and flexible. 
     The sling of the invention can be either non-inflatable or inflatable. In the inflatable embodiment, as shown in the slings  2   a  to  2   f , the first sling element is provided with a port  8   a  to  8   f  and the second sling element is provided with a port  18   a  to  18   d , respectively. The sling is inflated by introducing an inflation material into an interior of each of the sling fingers via one or both of the ports  8  and  18 . Each of the ports  8  and  18  is provided with a unidirectional valve  100 , shown in the cut-away section shown in  FIG. 2  which allows each element to be filled by inserting the tip of a syringe filled with the inflation material through the valve and then withdrawing the syringe from the valve. A cut-away view of an inflated finger-like projection is shown in  FIG. 3 . Inflation of the sling provides stiffness to the extensions for providing stiffer support to the urethra without causing additional compression to the urethra. Such an increase in stiffness can also be obtained mechanically by stretching the extensions using a flexible wire or ribbons for pushing the tips of the fingers. 
       FIGS. 4 a  to 4 e    show slings  20   a  to  20   e , respectively, in accordance with five additional embodiments of the invention. The slings  20   a  to  20   e  comprise a first sling element  24   a  to  24   e , respectively, and a second sling element  26   e  to  26   e , respectively. The slings  20   a  to  20   e  can be either non-inflatable or inflatable. In the inflatable embodiment, the first sling element is provided with a port  28   a  to  28   e  and the second sling element is provided with a port  38   a  to  38   e , respectively. The port may be the port  100 , shown in  FIG. 2 , as explained above in reference to the slings shown in  FIG. 1 a   . From the ports  28   a  to  28   e  extend one or more finger like projections  29   a  to  29   e . From the ports  38   a  to  38   e  extend one or more finger like projections  39   a  to  39   e , respectively. The slings  20   a  to  20   e  differ in the number and lengths of the finger-like projections. Thus, for example, in the sling  20   a , three finger-like projections are shown on each of the elements  24   a  and  26   a . This is by way of example only, and each element can have any number of finger-like projections and finger lengths as required in any application. The number of projections on the two elements may be the same, or may be different. 
     The first and second sling elements are integral with each other by means of a plurality of constrictions  32 . The constrictions  32  are weak points in the sling and are configured to tear when the first and second sling elements are pulled apart, as explained below. In addition, the projections on the first and second sling elements are attached together at a plurality of weak lateral connections  35 , shown in greater detail in the insert to  FIG. 4 c   . the lateral connections  35  tend to maintain the projections  29  and  39  parallel to each other. 
     The slings  20   a  to  20   e  are made from a fluid impervious, biocompatible material such as silicone. The material of the slings is preferably inelastic and soft and flexible. 
     The slings  20   a  to  20   e  are either inflatable or non-inflatable. In the inflatable embodiment the sling is inflated by introducing an inflation material into an interior of each of the sling fingers via one or both of the ports  28  and  38 . Each of the ports  28  and  38  is provided with a unidirectional valve which allows each element to be filled by inserting the tip of a syringe filled with the inflation material through the valve and then withdrawing the syringe from the valve. 
       FIG. 5  shows a sling  20   f , in accordance with yet another embodiment of the invention. The sling  20   f  comprises a first sling element  24   f , and a second sling element  26   f . The slings  20   f  can be either non-inflatable or inflatable. In the inflatable embodiment, the first sling element is provided with a port  28   f  and the second sling element is provided with a port  38   f . The port may be the port  100 , shown in  FIG. 11 , as explained above in reference to the slings shown in  FIG. 1 . From the port  28   f  extend one or more finger like projections  29   f . From the port  38   f  extend one or more finger like projections  39   f . The sling  20   f  is provided with a plurality of weak points, which in this embodiment are perforations  31 . The perforations  32  are configured to tear when the first and second sling elements are pulled apart, as explained below. In addition, the projections on the first and second sling elements are attached together at a plurality of weak lateral connections  35 , as explained above in reference to the slings  20   a  to  20   e , that tend to maintain the projections  29  and  39  parallel to each other. 
     The sling  20   f  can be made from a fluid impervious, biocompatible material such as silicone. The material of the slings is preferably inelastic and soft and flexible. 
       FIG. 6 a    shows a sling  40  in accordance with yet another embodiment of the invention. The sling  40  has a first end  48  and a second end  58 . The first and second ends are joined by a plurality of narrow strands or fibers  42 , shown in greater detail in  FIG. 4 b   . In each strand are one or more of constrictions  46 , shown in greater detail in the insert to  FIG. 6 b   . The constrictions  46  are weak points in the sling and are configured to-detach when the first and second ends of the sling are pulled apart, as explained below. The sling  40  is not-inflatable. 
       FIG. 7 a    shows a sling  60  in accordance with till another embodiment of the invention. The sling  60  is woven from fibers  62  shown in greater detail in  FIG. 7 b   . The sling  60  comprises a first sling element  63   a  having an end  68   a , and a second sling element  63   b  having an end  68   b . The first and second sling elements are interwoven so as to form an integral unit. The ends  68   a  and  68   b  may be grasped and pulled apart causing the first and second sling elements to detach from each other. 
       FIGS. 8 and 9  show an end  170  and  172 , of a sling  171  and  173 , respectively, in accordance with another embodiment of the invention. Finger-like extensions  174  and  176 , respectively are attached by a monofilament wire  178  to the ends,  170  and  172 , respectively, thus connecting the elements of the sling.  FIGS. 16 and 17  show different connecting schemes. Pulling the end of the wire  178  which is located at the end of the sling, removes the wire  178  and releases the fingers  174  and  176  from the end,  170  and  172 , respectively, allowing removal of the sling components. Alternatively, the elements of the sling may be pulled apart which pulls the wire together with one of the elements of the sling during separation. 
       FIG. 10  shows an inflatable sling  105  in accordance with another embodiment of the invention. The sling  105  has a single inflatable unit having three finger-like projections  102  which is inflated through a port  108 . [The invention, as defined in the claims, is a sling having two parts that separate when the parts are pulled apart. It&#39;s not clear how the embodiment of  FIG. 8  fits into this definition.] 
       FIG. 11  shows an inflatable sling  106  having two inflatable units  108  and  110 . The inflatable unit  108  and  110  has an inflation port  109  and  111 , respectively. 
     The inflatable unit  108  and  110  has two finger-like projections,  112  and  114 , respectively. The projections  112  of the inflatable unit  108  are interdigitated with the projections  114  of the inflatable unit  110 . [It&#39;s not clear what holds this thing together] 
       FIG. 12  shows embedding a sling  125  of the invention between two layers of biodegradable and/or bioabsorbable mesh  126  for early fixation of the sling. The biodegradable material allows tissue ingrowth through its interstices and fixes the sling during the first weeks after its implantation. The mesh then disintegrates allowing the tissue to enter the longitudinal spaces along the fingers of the sling. The two layers of mesh  126  may be attached to one another by means of a snap-fit attachment. In one embodiment, shown in  FIG. 13 , a snap-fit attachment  127 , is achieved by a protrusion  129  in one layer  131  that snap-fits into a hole in the second layer  133 . In another embodiment, shown in  FIG. 14 , a snap fit attachment  139  is formed by mated protrusions  141  and  143  extending from the layers  131  and  133  respectively. A similar attachment can be used for attaching a third or fourth layer. 
       FIG. 15  shows a multilayered mesh sling  130 , in accordance with another embodiment of the invention for use in the treatment of POP. The mesh sling  130  comprises a top sling  132  and a bottom sling  134 . The perforated ends  136  and  140  of the layers are adapted to be fixed by tissue ingrowth. The perforated ends  136  and  140  are connected to fingers  135  at connecting points  137 . The fingered segment of each layer is removable by pulling this segment outward. The pulling causes a disconnection of the fingers from the permanent segment of the layer. The removable segment can be either inflatable or non-inflatable. The top sling  132  has a non-inflatable segment  136  and an inflatable segment  138 . Similarly, the bottom sling  136  has a non-inflatable segment  140  and an inflatable segment  142 . The layers of the sling can be snapped together and/or covered with biodegradable layers for early fixation. 
     The sling  130  can be mono-layered (wider than the suburethral slings and wider fixation ends) or multi-layered. The sling  130  can be removed by pulling its anterior end. The attachments detach from the narrow posterior end which remains attached to the posterior fixation tissues. 
     A sling of the invention, such as the sling  2   a , shown in  FIG. 1 a   , may be implanted, for example, using a trans-obturator approach, as shown in  FIG. 16 a   , a transabdominal or trans-vaginal approach, as shown in  FIG. 16 b   , or implanted as puborectal sling, as shown in  FIG. 16 c   . The sling  2   a  is implanted in an uninflated state as shown in  FIG. 4 . For implantation using the trans-oburator approach, shown in  FIG. 16 a   , the sling is introduced into the body through incisions at the level of one of the obturator foramine and a midline vaginal incision under the urethra  120  and then through the contralateral obturator foramine before exiting the body through a second incision. The ports  8   a  and  18   a  thus remain outside the body after implantation. The tip of a syringe is inserted in to the valve of the port  8   a  and the first element  4   a  is inflated with an inflation fluid expelled from the syringe. The second element  6   a  is inflated via the port  18   a  with a similar amount of inflating material. At any time, the amount of inflation fluid inside the inflatable elements  4   a  and  6   a  can be changed in order to readjust the sling tension when it is determined that the urethra  120  is not supported in a desired manner. 
     The sling ends can have mesh-like segments for self fixation. If a trans-obturator approach is used the mesh ends should be over the obturator fascia. If an abdominal approach is used the mesh ends should be over the rectus fascia, where the mesh tips can be reached easily to be disconnected from the removable sling, in case the slings has to be removed. 
     The sling of the invention may be provided with a muscle stimulating device  130 , shown schematically in  FIG. 12  for stimulating periurethral and/or pelvic muscle contraction for reinforcing the mechanical effect of the sling during a sudden abdominal pressure increase. The stimulating device  130  comprises one or more pressure and/or motion sensors  132  that monitor the pressure and/or motion of the sling. Signals from the sensors are input to a processor  134 . The processor  134  analyzes the sensor signals to detect a sudden increase in the pressure on the sling and/or a sudden increase in the motion of the sling. When a sudden increase in the pressure on the sling and/or a sudden increase in the motion of the sling is detected by the processor  134 , the processor  134  activates one or more electrodes  136  that are implanted in one or more adjacent muscles, such the periurethral and/or the pelvic muscles. Activation of the electrodes  136  causes contraction of the muscles in which the electrodes are implanted. Contraction of the muscles reinforces the mechanical effect of the sling. The voltage across the electrodes may be generated from natural body motions and stored, for example, in a capacitor. Upon detection of a sudden motion, such as sneezing or coughing, the capacitor can be discharged across the electrodes. 
     When implanted, the sling of the invention may become encapsulated by fibrous tissue. However, unlike a mesh sling, the sling  2   a  of the invention has a smooth surface which prevents invasion by the surrounding tissue. Spacing between adjacent finger-like projections in the sling allow vascularization of the tissues covering the sling. After encapsulation by fibrous tissue, the sling may be removed from the body, leaving behind the encapsulation which may function as an autologous sling. 
     At any time after implantation, the sling  2   a  may be removed from the body. For removal, each of the ports  8   a  and  18   a  or sling ends are reached through respective skin incisions and grasped and the two ports or ends are simultaneously pulled away from the body. As the two ports are pulled apart, the connections  12  are disconnected so that the elements  4   a  and  6   a  become separated as they are removed from the body. The linear breaking strength of the disconnection points as measured by straight-pull tensile strength test of the sling may be higher than the suddenly increasing intra-abdominal pressure causing the urine or fecal leak to prevent its in-situ breakage. The smooth inner surface of the capsule and the smooth elements of the sling act as lubrication which facilitates removal of the elements from the body.