Abstract:
A sling assembly including a surgical sling configured to be implanted during a surgical sling procedure. The sling includes first and second regions and a central portion. The sling assembly further includes a removable sheath assembly situated about the surgical sling. The removable sheath assembly includes first and second upper sheaths. The first upper sheath is configured to be situated about the first region of the surgical sling, and the second upper sheath is configured to be situated about the second region of the surgical sling. The removable sheath assembly further includes a lower sheath. The lower sheath is configured to be situated about the central portion of the surgical sling and to be in cooperative association with both the first and second upper sheaths.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a surgical instrument and a method for treating female urinary incontinence. 
     2. Description of the Related Art 
     Urinary incontinence is a significant health concern worldwide. Incontinence may occur when the pelvic floor weakens. There are five basic types of incontinence: stress incontinence, urge incontinence, mixed incontinence, overflow incontinence and functional incontinence. There are a large number of surgical interventions and procedures for addressing incontinence. 
     A variety of surgical procedure options are currently available to treat incontinence. Depending on age, medical condition, and personal preference, surgical procedures can be used to completely restore continence. One type of procedure, found to be an especially successful treatment option for Stress Urinary Incontinence in both men and women, is a sling procedure. 
     A sling procedure is a surgical method involving the placement of a sling to stabilize or support the bladder neck or urethra. There are a variety of different sling procedures. Descriptions of different sling procedures are disclosed in U.S. Pat. Nos. 5,112,344; 5,611,515; 5,842,478; 5,860,425; 5,899,909; 6,039,686, 6,042,534 and 6,110,101. 
     Sling procedures differ in the type of material used for the sling, the method of anchoring the sling material in the body and how the sling material is inserted in the body. The time required for a surgical procedure varies, but is preferably as short as possible. This factor is frequently reported in urology and gynecology literature. See Atherton M. J., et al., A Comparison of Bladder Neck Movement and Elevation After Tension-free Vaginal Tape and Colposuspension, British Journal of Obstetrics and Gynecology, November 2000, Vol. 17, p. 366-1370, Nilsson et al, The Tension-free Vaginal Tape Procedure is Successful in the Majority of Women with Indications for Surgical Treatment of Urinary Stress Incontinence, British Journal of Obstetrics and Gynecology, April 2001, Vol. 108, P. 414-419; and Ulmsten et al., An Ambulatory Surgical Procedure Under Local Anesthesia For Treatment of Female Urinary Incontinence, Int. Urogynecol. J. (1996), v. 7, pps. 81-86. 
     Although serious complications associated with sling procedures are infrequent, they do occur. Complications include urethral obstruction, development of de novo urge incontinence, hemorrhage, prolonged urinary retention, infection, and damage to surrounding tissue and sling erosion. Infection may occur as a result of exposing contaminants from the vagina during the removal of prior art two piece overlapping sheath assemblies via either suprapubic incisions or groin incisions. A two piece overlapping sheath assembly is disclosed in published U.S. patent application No. 2002/0156487-A1. 
     Many slings include a protective sheath used during insertion of the sling. After the sling is implanted, the sheath is removed and discarded. The protective sheath is generally constructed of a material that affords visual examination of the implantable sling and that affords smooth passage of the sling assembly through tissue of the patient. 
     In many cases, the sheath is made of polyethylene. Other materials used to construct the sheath include polypropylene, nylon, polyester or Teflon. The sheath material should be flexible and provide sufficient structural integrity to withstand the various forces exerted on the sheath throughout the sling delivery procedure. Referring to  FIG. 14 , the sheath  44  is configured to have sufficient flexibility to facilitate user manipulation and adequate structural strength to withstand the various forces applied to the sheath  44  during delivery and/or positioning of the sling assembly. It should also conveniently separate from the sling material after the sling is implanted without materially changing the position of the sling. 
     The sheath  44  may comprise two elongate, separable sections  86 . Portion S of the sheath  44  detachably and telescopically overlap near the middle portion of the sling. During sheath removal, the first section and the second section of the sheath are slid off the sling by pulling each end  86  of the sheath  44  away from the middle portion of the sling assembly. Removal of the sheath  44  causes separation of the overlapping sheath sections, thereby exposing the sling. 
     The problem with the telescoping configuration of the first and second sections of the sheath  44  is that there has been a tendency for the two telescoping sections to “stick” to one another during the removal process believed to be due to either friction caused by the respective telescoping sections of the sheath or use of a spacer such as a clamp under the urethra. In the latter, the spacer increases the friction between the two sheaths and causes them to stick. That is, the overlapping section of the first and second sections of the sheath is situated at the point of maximum curvature and hence the point of maximum interference/friction. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a sling assembly including a sheath assembly that is easily removed from a surgical sling after the sling assembly is situated under the patient&#39;s urethra, the sheath assembly including two upper sheaths and a lower sheath. 
     Further, it is an object of the present invention to provide a spacer configured to be placed between the surgical sling and the patient&#39;s urethra after the portion of the sheath assembly situated below the patient&#39;s urethra (i.e., the lower sheath) has been removed. 
     Further, it is an object of the present invention to reduce the amount of exposed material moved from the vaginal region to another part of the patient&#39;s body (e.g., the abdominal or groin region); 
     Finally, it is an object of the present invention to provide a method for removing the three piece sheath assembly after the sling assembly has been placed under the urethra. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a sling assembly having a three piece removable sheath according to the present invention; 
         FIG. 2  is a perspective view of the pubic area of a patient relative to a sling assembly including two needles, two dilators, a surgical sling, and a three piece sheath assembly according to the present invention prior to the surgical sling and the sheath assembly being placed under the patient&#39;s urethra using a suprapubic approach; 
         FIG. 3  illustrates the two needles as they are withdrawn through two suprapubic incisions in order to position the surgical sling and the protective sheath under the patient&#39;s urethra; 
         FIG. 4  illustrates a process of removing the lower sheath after the surgical sling has been positioned underneath the patient&#39;s urethra; 
         FIG. 5  illustrates the process of removing the two upper sheaths after the lower sheath has been removed; 
         FIG. 6  illustrates the placement of the surgical sling after the sheath assembly has been removed and the ends of the sling assembly have been cut-off at the suprapubic incisions; 
         FIG. 7  illustrates the sheath assembly of the present invention in conjunction with a trans-obturator sling assembly; 
         FIG. 8  illustrates the process of removing the lower sheath after the surgical sling has been positioned underneath the patient&#39;s urethra using the trans-obturator sling assembly system; 
         FIG. 9  illustrates the process of removing the two upper sheaths after the surgical sling has been positioned underneath the patient&#39;s urethra using the trans-obturator sling assembly system; 
         FIG. 10  is a magnified view of the pubic area illustrated in  FIG. 9 ; 
         FIG. 11  is a cross-sectional view of the lower sheath and the surgical sling; 
         FIG. 12  is a perspective view of a spacer mechanism with jaws open; 
         FIG. 13  is a perspective view of a spacer mechanism with jaws closed; and 
         FIG. 14  is a perspective view of the prior art sheath assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.  FIG. 1  illustrates a sling assembly  10  including a surgical sling  11  and three sheaths, two upper sheaths  12  and  14  and a lower sheath  20 . The sling  11  and the three sheaths  12 ,  14 , and  20  are made of biocompatible materials having sufficient strength and structural integrity to withstand the various forces exerted upon these components during an implant procedure and/or following implantation within a patient. Suitable implantable materials (i.e., slings) associated with the present invention include synthetic and non-synthetic materials. Suitable non-synthetic implantable materials include human fascia lata, treated animal (e.g. bovine or porcine or equine pericardium) tissue, autologous tissue, cadaver tissue, homografts, xenografts, heterografts, allografts and combinations of such materials. Suitable synthetic materials include knitted polypropylene slings alone, such slings with surrounding sheaths, or silicone coated polymer slings, such as those described in published U.S. patent application No. 2002/0072694-A1. 
     The sheaths  12 ,  14 , and  20  are preferably made of polyethylene. Other materials including, without limitation, polypropylene, nylon, polyester, or Teflon can also be used. In a preferred embodiment, the sling comprises a mesh material. The mesh material may comprise one or more woven, knitted or inter-linked filaments or fibers that form multiple fiber junctions throughout the mesh. The filaments may comprise monofilaments or braided filament. The fiber junctions may be formed via weaving, knitting, braiding, bonding, ultrasonic welding or other junction forming techniques, including combinations thereof. In addition, the size of the resultant openings or pores of the mesh may be sufficient to allow tissue in-growth and fixation within surrounding tissue. As an example, not intended to be limiting, the holes may comprise polygonal shaped holes with diagonals of 0.132 inches and 0.076 inches. 
     The quantity and type of fiber junctions, fiber weave, pattern, and material type influence various sling properties or characteristics. As another example, not intended to be limiting, the mesh may be woven polypropylene monofilament, knitted with a warp tricot. The stitch count may be 27.5 courses/inch (+ or − 2 courses ) and 13 wales/inch (+ or − 2 wales). The thickness of this example is 0.024 inches. Non-mesh sling configurations are also included within the scope of the invention. In a one embodiment, a polypropylene sling mesh is constructed of polypropylene monofilament. The mesh may be precut to a predetermined size (e.g. about 1.1 cm width×35 cm length). An absorbable tensioning suture is preferably threaded into the length of the sling mesh to allow for tensioning adjustment of the sling mesh after placement in the patient is achieved. 
     In a preferred embodiment, the mesh is preferably an elastic, as opposed to a substantially inelastic mesh. A test for differentiating between elastic meshes and substantially inelastic meshes is disclosed in U.S. Pat. application Ser. No. 10/386,897, filed Mar. 11, 2003 (the entire contents of which are herein incorporated by reference). 
     Dilators  54  are optionally attached to the ends of the sling assembly  10 . The dilators  54  atraumatically create and/or expand the passageway through the tissues for sling assembly delivery. 
     Tab portion  24  is preferably connected to the lower sheath  20  via suture  22 . Tab portion  24  is designed and shaped to be pulled by the thumb and one of the fingers through a vaginal incision of the patient. A cross-sectional view is shown in  FIG. 11 . As can be seen from  FIG. 11 , a removal assembly including a tube  70  is situated within lower sheath  20  below sling  11 . The longitudinal length of the tube  70  is perpendicular to the longitudinal length of the lower sheath  20 . Further, the tube  70  is preferably situated at the mid-portion of the lower sheath  20  measured lengthwise. Through holes  74  are placed in the lower sheath  20  adjacent the ends of the tube  70 . Suture  22  is a closed loop threaded through holes  74  and a hole placed in tab  24 . Alternatively, the suture  22  is fastened to tab  24  using any biocompatible adhesive. In either case, the removal assembly should have sufficient strength and structural integrity to withstand the force necessary to remove the lower sheath  20  from the sling  11  by pulling on the tab  24 . 
       FIG. 11  further illustrates the relationship between upper sheath  12  and lower sheath  20 . The lower sheath  20  can be placed telescopically within upper sheath  12  as illustrated in  FIG. 11 . Alternatively, the upper sheaths  12  and  14  can be placed telescopically within the lower sheath  20 . A slit  72  is placed along the longitudinal length of the lower sheath  20  in order to allow the lower sheath  20  to be removed from the sling  11  when the tab  24  is pulled. Alternatively, the slit can comprise a score or other weakening of the sheath material including a kiss cut. 
       FIG. 2  illustrates the sling assembly  10  of the present invention in conjunction with needles  60  and handles  64  used in a suprapubic approach. The sling assembly  10  may be implanted by a wide variety of surgical approaches such as transabdominal (i.e. suprapubic or from above), transvaginal (from below), or transobturator (e.g. with the sling anchored in the obturator foramen). Various surgical tools for implanting sling assemblies, sling assemblies and surgical approaches are disclosed in U.S. Pat. No. 6,612,977; published U.S. patent application Nos. 2002-0107430-A1, 2002-0147382, 2002-0099258-A1 and US-2002-0099259-A1; and U.S. pat. application Ser. No. 10/306,179 filed Nov. 27, 2002, all of the above incorporated herein by reference thereto. The dilators  54  dilate a needle track for ease of sling introduction and positioning within the patient. An end of the needle  60  is preferably keyed to allow for convenient, secure attachment of the needle  60  relative to the dilator  54 . 
     The dilator  54  atraumatically creates and/or expands the passageway through the tissues for sling assembly delivery. The dilator  54  is short relative to a needle  60  for ease of passage of the assembly and to reduce the overall amount of tissue that is deflected at one time. The dilator is less than 2.5 inches in length. The maximum radius of a dilator  54  is less than 10 mm. The tip of the dilator  54  is blunt, as the leading tip of the dilator  54  will pass through tissue that has already been pierced by a needle  60 . As shown in  FIG. 2 , the needles  60  have been passed downward through a vaginal incision  404  and out the vagina  200 . The sling assembly has been associated with the needles  60  using dilators  54 .  FIG. 3  further illustrates suprapubic incisions  400 . The suprapubic incisions  400  enable the needles to be passed downward through the vaginal incision  404 . 
       FIG. 4  illustrates the positioning of the sling assembly  10  underneath the urethra  16 . The lower sheath  20  has been removed by pulling the tab  24  through the vaginal incision  404  and the vagina  200 . Thus, exposing the sling  11 . Because the lower sheath  20  is situated adjacent the urethra  16 , the lower sheath  20  is the sheath most exposed to vaginal contaminants of the three sheaths including upper sheaths  12  and  14 . The position where lower sheath  20  is placed relative to the urethra  16  substantially corresponds to the position of the overlapping portion S of the prior art sheath relative to the urethra. Both the lower sheath  20  and the overlapping portion of the prior art sheath are the most exposed portions of their respective sling assemblies. That is, those portions are exposed to the contaminants of the vaginal region. However, because in the present invention, the lower sling  20  is removed through vaginal incision  404  as opposed to a suprapubic incision, the lower sling  20  is not exposed to the body during removal thereof.  FIG. 4  further shows the sling after the dilators  54  have been cut off, but prior to final trimming. 
     In another embodiment, a spacer is inserted between the exposed sling and the patient&#39;s urethra until final positioning and tensioning adjustments are made to the sling  11 . The spacer can be for example a Hegar dilator, scissors, or Metzenbaum clamps, etc. Alternatively, the spacer can be a device as shown in  FIGS. 12 and 13 . See also U.S. patent application Ser. No. 10/646,082 entitled Surgical Article and filed on Aug. 22, 2003.  FIGS. 12 and 13  illustrate a spacer  90  including jaws  92  and  94 .  FIG. 12  illustrates the jaws  92  and  94  in an open state. The jaws  92  and  94  are positioned over and below the sling assembly  10  in a position where the jaws would clamp the lower sheath  20  when closed.  FIG. 13  illustrates the jaws  92  and  94  clamped on the sheath assembly  10 . Since the lower sheath  20  and the upper sheaths  10  and  12  do not overlap in the center of the sling underneath the urethra  16  and the assembly  10  is not tensioned against a spacer, the lower sheath  20  is easily removed. The upper sheaths  12  and  14  remain associated with the sling  11  at this time. According to one embodiment, a spacer (e.g., spacer  90 ) remains between the exposed sling and the urethra while the upper sheaths  12  and  14  are removed. Because the upper sheaths  12  and  14  do not overlap the lower sheath  20  at the center of the sling  11  underneath the urethra and the sling assembly  10  is not tensioned against a spacer, the upper sheaths  12  and  14  can be removed easily. 
     In another embodiment, the upper sheaths  12  and  14  are removed prior to removing the lower sheath  20  (no spacer is used). Because sheaths are designed to aid in passing the sling into the body with little resistance, if the upper sheaths are not removed prior to removing the lower sheath, the sling may slide up when the upper sheaths are pulled and could cause over tensioning of the sling, placing the patient in retention. By removing the upper sheaths first, the sling is exposed to the patient&#39;s tissue anchoring the sling in place for the removal of the lower sheath. 
     According to another embodiment, a time advantage may be obtained by using a spacing mechanism (e.g., spacer  90 ) and by removing the upper sheaths first. This is due to the fact that if the upper sheaths  12  and  14  are removed prior to removing the lower sheath, the sling will become anchored into the body. If this is done with a spacing mechanism in place, the sling is anchored at the right tension. The spacing mechanism can then be removed and the lower sheath  20  removed vaginally without affecting the tension. By allowing the spacer mechanism to be placed over the lower sheath  20 , the surgical method does not require the step of attaching the spacing mechanism to the sling after insertion of the sling and removal of the lower sheath  20 . According to another embodiment, the sling assembly could be provided with the spacer integrated thereto. Another advantage would be that the sling can be pulled to the proper tension when removing the needles and the attached sling assembly rather than having to leave the sling initially loose to allow placement of the spacer between the urethra and sling after removing the lower sheath. 
       FIG. 5  illustrates removing the upper sheaths  12  and  14  through the suprapubic incisions  400 . The final placement of the sling assembly using a suprapubic approach is illustrated in  FIG. 6 . The ends of the sling  11  are cut off and anchored in the abdominal region at the suprapubic incisions  400 .  FIG. 6  further shows tensioning suture  66 . Tensioning suture  66  may be used to center and properly position the sling assembly  10  under the midurethra after the dilators  54  have been removed. 
       FIG. 7  illustrates the sling assembly according to the present invention as it would be used in conjunction with a trans-obturator sling assembly. U.S. patent applications Ser. No. 10/306,179 filed Nov. 27, 2002 and No. 10/386,897 filed Mar. 11, 2003 describe a trans-obturator sling assembly and a method of use and are hereby incorporated herein by reference. The trans-obturator sling assembly includes a handle  100 , a helical needle  62 , and a sling assembly  10  according to the present invention. A Foley catheter  2  with a balloon is used to move the urethra  16  out of harms way in order to allow, among other things, a vaginal incision to be made. More precisely, a mediane paraurethral incision is made in the region of the middle third of the urethra. A finger is slipped in the vaginal incision and is guided to one side of the urethra in order to locate an obturator foramen. An incision  600 B is made adjacent thereto in the groin region. Handle  100  is used to guide helical needle  62  through the incision  600 B and out the vaginal incision. Dilator  54 B is then attached to the needle  62  and the sling assembly is pulled through the vagina and out of the skin. 
     A finger is slipped in the vaginal incision and is guided to the opposite side of the urethra  16  in order to locate the second obturator foramen. An incision  600 A is made adjacent thereto. A second helical needle shaped and sized to be used on the opposite side of the urethra is then passed through the skin incision  600 A using handle  100  and out the vaginal incision. Dilator  54 A is then attached to the second helical needle and the sling assembly is pulled through the vagina and out of the groin incision  600 A. The sling assembly  10  is consequently positioned underneath the urethra. More particularly, the lower sheath  20  is positioned underneath the urethra  16 . 
       FIG. 8  illustrates the placement of the sling assembly  10  after the lower sheath  20 A has been removed there from via the vaginal incision. As described above regarding the suprapubic approach, suture  22 A is pulled by pulling tab  24 A in order to remove the lower sheath  20 A via the vaginal incision.  FIG. 8  further illustrates that one of the dilators  54  has been cut-off. After the second dilator  54  is removed, as shown in  FIG. 9 , the upper sheaths  12 A and  14 A can be removed. As discussed above with regard to the suprapubic approach, a spacer (e.g., spacer  90 ) can be placed between the sling  11  and the urethra  16  after the lower sling  20 A has been removed. As can be further seen from  FIG. 9 , the end of the sling  42  is anchored outside of the obturator foramen  3 .  FIG. 10  is a magnified view of the pubic region illustrated in  FIG. 9 . 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. For example, the sheath assembly of the present invention can be used during a transvaginal approach. After a sling and the sheath assembly of the present invention is situated under the urethra, the lower sheath can be removed via the vaginal incision and the upper sheaths can be removed via the suprapubic incisions. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.