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Synthetic Midurethral Slings for the Correction of Stress Incontinence


In 1996, Ulmsten and colleagues introduced the first synthetic midurethral sling, which they named the tension-free vaginal tape (TVT) procedure. This procedure introduced the concept of placing a synthetic material (polypropylene) under the midportion of the urethra in a tension-free fashion. The technique quickly gained popularity because it involved minimal vaginal dissection, was easy to learn, and could be performed with the patient under local anesthesia on an outpatient basis. To date, several studies have compared the TVT procedure with more traditional procedures such as the Burch colposuspension and autologous pubovaginal slings and have shown equal to superior cure rates with less morbidity. The success of the original TVT midurethral sling has led to the development of many other retropubic midurethral slings ( Table 55.1 ).

TABLE 55.1
Commercially Available Retropubic Midurethral Sling Kits
Sling Manufacturer Trocar Passage
TVT, TVT Exact Ethicon, Somerville, N.J. Bottom-up
SUPRIS Coloplast, Minneapolis, Minn. Top-down
Lynx suprapubic Boston Scientific, Marlborough, Mass. Top-down
Advantage Boston Scientific Bottom-up
DESARA; Retropubic CALDERA Medical, Agora Hills, Calif. Bottom-up or top-down
TVT , Tension-free vaginal tape.

Delorme described the first transobturator synthetic midurethral sling. The motivation behind the development of this approach was to reduce the risk of bladder perforation and eliminate the risk of bowel or major blood vessel injury, which had been reported due to blind passage of the trocar through the retropubic space. Subsequent studies have shown that a transobturator midurethral sling is as efficacious as a retropubic synthetic midurethral sling in women suffering from primary stress incontinence due to urethral hypermobility. Table 55.2 lists commercially available transobturator and urethral sling kits.

TABLE 55.2
Commercially Available Transobturator Midurethral Sling Kits
Reprinted with permission from Walters MD, Karram MM: Urogynecology and Reconstructive Pelvic Surgery, 4th ed. Philadelphia, Elsevier, 2014.
Sling Manufacturer Trocar Passage
TVT-O Gynecare, Somerville, N.J. Inside-out
TVT-Abbrevo Gynecare Inside-out
DESARA—TOT CALDERA Medical, Agora Hills, Calif. Inside-out or outside-in
Obtryx Boston Scientific, Marlborough, Mass. Outside-in
Aris Coloplast, Minneapolis, Minn. Outside-in
TVT , Tension-free vaginal tape.

More recently, single-incision midurethral slings have been described. This newest version of a polypropylene sling requires only one incision in the vagina because the sling has no exit points. Table 55.3 lists commercially available single-incision slings. This chapter discusses the anatomy and currently recommended techniques for the placement of these various synthetic midurethral slings. Also discussed is how best to manage postoperative retention and/or voiding dysfunction after a synthetic midurethral sling.

TABLE 55.3
Commercially Available Single-Incision Midurethral Sling Kits
Sling Manufacturer
Solyx Boston Scientific, Marlborough, Mass.
Altis Coloplast, Minneapolis, Minn.
DESARA SIS CALDERA Medical, Agora Hills, Calif.

Retropubic Synthetic Midurethral Slings

The TVT procedure was the first retropubic synthetic midurethral sling. This ambulatory procedure aims to restore the pubourethral ligament and suburethral vaginal hammock with specially designed needles attached to a synthetic sling material. The synthetic sling material is made of polypropylene and is approximately 1 cm wide and 40 cm in length. This sling material is attached to two stainless steel needles, which are passed on each side of the urethra blindly through the retropubic space to exit through a previously created stab wound in the suprapubic area. Fig. 55.1 illustrates the original TVT. Because this type of sling requires blind passage of a needle through the retropubic space, it is imperative that the surgeon have a clear understanding of the important anatomic structures of the retropubic space to avoid potential complications ( Figs. 55.2 to 55.5 ). Besides the potential for damaging the urethra or the bladder, there is also potential for injuring important vascular structures, including the obturator neurovascular bundle and the external iliac vessels, as they exit the pelvis (see Figs. 55.2 to 55.5 ). Rarely, small bowel can be injured if the trocar migrates in a cephalad direction away from the back of the pubic bone or if small bowel is adhered in the lower pelvis from previous surgery or infection ( Fig. 55.6 ).

FIG. 55.1, A. Tension-free vaginal tape instrumentation, including (clockwise from top) a Foley catheter guide, a needle introducer/handle, and specially designed needles attached to a synthetic suburethral sling tape. B. Needles have been attached to the handle. A hemostat has been placed on the overlapping plastic sheath.

FIG. 55.2, The relationship of the tension-free vaginal tape (TVT) needle to the vascular anatomy of the anterior abdominal wall and retropubic space. Numbers represent the mean distance from the lateral aspect of the TVT needle to the medial edge of the vessels. a, Artery; v, vein.

FIG. 55.3, A. View of the retropubic space of a fresh cadaver. B. Cooper’s ligament, the obturator neurovascular bundle as it exits the pelvis through the obturator foramen, and the external iliac vessels as they exit the pelvis under the inguinal ligament are marked. C. A tension-free vaginal tape (TVT) needle has been passed in an appropriate fashion on the left side of this cadaver. D. The TVT needle is intentionally continued in a cephalad-lateral direction, and one can see how it can easily come into contact with the obturator neurovascular bundle in the retropubic space. E. The TVT needle is intentionally continued in this direction, and one can see how it could potentially come in contact with the external iliac vessels.

FIG. 55.4, Retropubic view of an embalmed cadaver. Note the appropriate passage of the tension-free vaginal tape needle on the right side and the normal anatomy of other structures in the retropubic space.

FIG. 55.5, Retropubic view of appropriate safe passage of a retropubic tension-free vaginal tape needle (middle illustration). A. Cephalad migration of the needle away from the back of the pubic bone is the most common cause of bladder perforation. B. External rotation of the handle will initially result in penetration of the obturator internus muscle by the needle tip, with the potential to injure aberrant vessels along the lateral pelvic sidewall. C. Continued external rotation of the handle with cephalad migration of the needle may result in injury to the obturator neurovascular bundle or ( D ) the external iliac vessels.

FIG. 55.6, Photograph of a tension-free vaginal tape ( TVT ) that was passed through a loop of small bowel.

A retropubic synthetic sling can be placed in one of two ways, either passing the trocars from a vaginal incision to exit suprapubically (bottom to top) or from a suprapubic incision to exit into the vagina (top to bottom).

Surgical Technique: Bottom to Top

  • 1.

    Anesthesia and preoperative considerations. I prefer to use general anesthesia; however, some surgeons prefer intravenous sedation with local anesthesia to allow the performance of the cough stress test to facilitate appropriate tensioning of the sling. Because approximately 50% of cases are done in conjunction with a prolapse repair, all surgeons need to be well versed at tensioning techniques under general anesthesia. A single dose of a cephalosporin is usually given preoperatively. Sterile urine should be confirmed before the procedure. I prefer to mark the sites of the suprapubic incisions before the vaginal dissection ( Fig. 55.7 ).

    FIG. 55.7, Site of suprapubic incisions for the tension-free vaginal tape procedure.

  • 2.

    Vaginal dissection. The anterior vaginal wall is hydrodistended with a combination of lidocaine and epinephrine, with the goal of completely blanching the anterior vaginal wall at the level of the mid to distal urethra. A scalpel blade is used to make an incision from just below the external urethral meatus to the level of the midurethra. The vaginal wall is sharply dissected with Metzenbaum scissors off the posterior urethra, creating small tunnels to the inferior pubic ramus. Sharp dissection is required because the distal anterior vaginal wall and posterior urethra are fused at this level ( Fig. 55.8 ). Some physicians prefer to hydrodissect the trocar trajectory bilaterally before passing the trocars by using a spinal needle, and suprapubically injecting fluid along the back of the pubic bone.

    FIG. 55.8, A. The external urethral meatus is grasped with an Allis clamp at the 6-o'clock position. B. A small midline incision is made at the level of the midurethra. C. Mayo or Metzenbaum scissors are used to create a tunnel to the inferior pubic ramus. The urogenital diaphragm is not penetrated.

  • 3.

    Trocar passage. A catheter guide is placed in the indwelling Foley catheter so that the urethra and bladder neck can be displaced away from where the trocar is inserted. The trocar tip is inserted into the previously dissected tunnel on each side lateral to the urethra and advanced to the undersurface of the pubic bone. The tip of the trocar should be sandwiched between the index finger of the surgeon’s nondominant hand, placed in the anterior vaginal fornix and the undersurface of the interior pubic ramus. The tip of the needle is carefully advanced through the endopelvic fascia into the retropubic space. When the resistance of the endopelvic fascia is overcome and the tip of the needle is in the retropubic space, the handle of the trocar is dropped and the needle is advanced through the retropubic space as it hugs the back of the pubic bone. The next resistance felt is the rectus muscle and anterior abdominal fascia. The needle is advanced through these structures to exit through the previously made suprapubic stab wound ( Fig. 55.9 ).

    FIG. 55.9, Proper technique for passing a retropubic trocar. A. The tip of the needle is placed in the small tunnel that has been created and should come into direct contact with the inferior pubic ramus, pointing toward the ipsilateral shoulder. With the index finger of the nondominant hand in the vagina and the thumb on the shaft of the needle, the tip is pushed through the urogenital diaphragm. B. Once the resistance of the urogenital diaphragm is overcome, the handle is dropped and the needle is moved in a medial and superior direction, while direct contact with the back of the pubic bone is maintained. Cephalad migration must be avoided. The tip of the needle is then palpated suprapubically and is guided to exit through the previously created stab incision.

  • 4.

    Cystoscopy. Cystoscopy is performed with a 30- or 70-degree scope to evaluate the bladder for inadvertent trocar injury with the trocar in place. If such an injury were to occur, it would generally be visualized in the anterolateral aspect of the bladder (usually the area between the 1-o’clock and 3-o’clock positions on the left side and the 9-o’clock and 11-o’clock positions on the right side). If the trocar is seen or there is any creasing of the bladder mucosa that does not disappear with bladder distention, the trocar should be withdrawn and repassed. Most commonly, when the bladder is perforated (which occurs in approximately 3% to 5% of cases), it is because the surgeon has allowed the trocar to migrate away from the back of the pubic bone in a cephalad direction ( Fig. 55.10 ). During repassing of the trocar, great care should be taken to hug the back of the pubic bone. In such cases, the patient may still proceed with the voiding trial postoperatively without the need for discharge with an indwelling catheter because the bladder perforation is very small and is usually in a high, nondependent portion of the bladder. If excessive hematuria is present or the perforation is in the base or trigone of the bladder, continuous postoperative bladder drainage should be undertaken. The length of drainage should be determined on the basis of the type and extent of the bladder injury.

    FIG. 55.10, A. Bladder perforation with a tension-free vaginal tape (TVT) on the patient’s left side. B. The shaft of the needle is now visible as it is withdrawn back into the vagina. C. The defect that is left in the bladder.

  • 5.

    As the ends of the mesh device are attached to the trocars on each side, the mesh with its plastic sheath is pulled up through the suprapubic stab wound along the trocar trajectory.

  • 6.

    Tensioning. Sling tensioning is very subjective and not standardized. In general, however, the sling is left loosely (tension free) under the urethra. Using a No. 8 Hegar dilator or a right-angle clamp inserted between the posterior urethra and the suburethral portion of the sling will help to facilitate appropriate tensioning. Some surgeons prefer to perform the procedure under local anesthesia and use a cough stress test. In such situations the sling is tensioned to the point at which minimal leakage occurs during coughing. Regardless of tensioning technique, the ultimate endpoint is to create a laxity in the mesh manifested by a ricochet of the mesh back toward the urethra if pulled on vaginally with a right-angle clamp while also avoiding direct mesh contact with the underside of the urethra. After, the plastic sheaths covering the mesh are removed, and tension of the mesh is rechecked. The mesh is resected flush with the skin suprapubically, making sure to mobilize the skin away from the mesh ends before skin closure ( Figs. 55.11 to 55.15 ).

    FIG. 55.11, The tape has been passed suprapubically on both sides. Leakage of urine during a coughing stress test indicates the need for adjustment of the sling material.

    FIG. 55.12, Tension-free vaginal tape needles and a plastic sheath containing Prolene tape have been passed up through suprapubic stab wounds.

    FIG. 55.13, A right-angle clamp stabilizes the Prolene while the plastic sheath is being withdrawn suprapubically.

    FIG. 55.14, Prolene tape after the plastic sheath has been removed.

    FIG. 55.15, Tension-free Prolene tape at the level of the midurethra.

  • 7.

    The vaginal wound is copiously irrigated and closed with a running 3-0 polyglycolic acid suture. The suprapubic stab wounds are closed with absorbable suture or liquid tissue adhesive. Vaginal packing may be inserted temporarily at the completion of the case if the patient is bleeding or concurrent prolapse procedures are being performed.

  • 8.

    The catheter may be removed along with the vaginal packing in the recovery room, and the patient is discharged after confirming voiding efficiency. The procedure is further illustrated in Figs. 55.16 to 55.19 .

    FIG. 55.16, Vaginal incision for a retropubic midurethral sling. Tunnels are created bilaterally to allow trocars to come into direct contact with the inferior pubic ramus.

    FIG. 55.17, Technique for initial passage of trocars through the vaginal incision toward the retropubic space. TVT , Tension-free vaginal tape.

    FIG. 55.18, Technique for passage of trocars through the retropubic space.

    FIG. 55.19, Technique for tensioning a retropubic sling.

Surgical Technique: Top to Bottom

  • 1.

    Vaginal dissection. The vaginal incision should be larger than described for the bottom-to-top technique because the dissection should allow placement of the index finger of the surgeon’s nondominant hand into the incision so as to pick up the tip of the needle as it passes into the vaginal incision.

  • 2.

    Top-to-bottom trocar passage. Before passage of the trocars, complete drainage of the bladder is ensured. At the previously marked puncture sites in the suprapubic region, a stab incision is made on each side. The incisions should be well within the pubic tubercles bilaterally. A trocar is inserted into the first of the suprapubic incisions while aligning with the sagittal axis of the body and then carefully puncturing through the anterior rectus sheath. Angling caudally and “walking off” the superior posterior edge of the pubic bone, the trocar is advanced into the retropubic space maintaining close contact with the posterior surface of the pubic bone. Concurrently, the surgeon’s finger is inserted into the previously dissected periurethral space on the ipsilateral side to provide control of the distal tip of the trocar. In a controlled manner, the trocar is progressively advanced until the tip is visible in the vaginal incision. Figs. 55.20 to 55.22 illustrate the technique of top to bottom trocar passage. Cystoscopy as previously described is performed to confirm that the needle did not penetrate the bladder. The same maneuver is performed on the contralateral side.

    FIG. 55.20, Vaginal incision and dissection for top-to-bottom retropubic midurethral sling .

    FIG. 55.21, Technique for passage of top-to-bottom trocar through vaginal incision . SPARC , Suprapubic arc.

    FIG. 55.22, Side view illustrating how a top-to-bottom trocar should hug the back of the pubic bone.

  • 3.

    Loading of the mesh. The mesh is attached to the trocars, and the trocars are withdrawn through the suprapubic stab wounds. Tensioning of the sling is as previously described for the bottom-to-top technique ( Fig. 55.23 ).

    FIG. 55.23, A. The SPARC (suprapubic arc) procedure (American Medical Systems, Minnetonka, Minn.), which is a suprapubic approach to a retropubic synthetic midurethral sling. B. The connector used with the SPARC procedure allows transfer of the sling into the suprapubic area.

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