Treating stress urinary incontinence with suburethral slings
Recent modifications to suburethral sling procedures have brought them to the forefront of stress urinary incontinence treatment. Here, the authors review the advances and evidence on synthetic and organic slings.
Technique
Conventionally, suburethral slings were placed via a combined vaginal and abdominal approach into the retropubic space of Retzius. Alternatively, the procedure could be performed abdominally by creating a suburethral tunnel via pelvic incisions, but this is the most difficult route.
Most recently, technological advances have simplified the vaginal approach, which utilizes minimal suburethral dissection and small suprapubic incisions. This technique is subdivided into “bottom-up” and “top-down” approaches. In the bottom-up TVT, the sling is inserted into a vaginal incision and threaded up through the patient’s pelvis, exiting from a small suprapubic incision. The topdown SPARC entails a reverse approach, starting from a suprapubic incision and exiting from a vaginal incision. New modifications allow for an abdominal TVT approach, as well, which we describe in detail in a later section.
Surgeons who are familiar with traditional needle suspensions may be more comfortable with the top-down approach. The need for concomitant surgery (e.g., hysterectomy or prolapse repair) not only determines the type of incontinence procedure, but also dictates the approach.
Preparing the patient. Place the patient under regional or local anesthesia with sedation so that an intraoperative cough stress test can be performed. Then administer an intravenous dose of a broad-spectrum antibiotic. Insert a 16 to 18 French Foley catheter into the urethra. Mark the suprapubic region 1 cm above and 1 cm lateral to the pubic symphsis on the left and right sides of the patient. Inject approximately 20 cc of a 1:1 mixture of local anesthetic and normal saline into the marked areas. We typically use 60 cc of 0.25% bupivicaine with epinephrine, diluted 1:1 with 60 cc of normal saline. After administering the local anesthetic suprapubically, inject a similar solution into the anterior vaginal wall suburethrally in the midline and laterally toward the retropubic tunnels.
Making the incisions. Both the TVT and SPARC techniques utilize the same type and location of incisions. As such, make a 0.5-cm incision into the abdominal skin on each side of the midline, approximately 1 cm lateral to midline and 1 cm above the pubic symphsis. Next, make a 1.5- to 2-cm vertical incision in the vaginal mucosa, starting 1.5 cm from the urethral meatus (FIGURE 1). Use Metzenbaum scissors to dissect the vaginal mucosa from the pubocervical fascia sub- and para-urethrally on both sides (FIGURE 2). Insert a Foley catheter guide (similar to the Lowsley retractor) into the catheter and deviate it to the ipsilateral side, thereby retracting the bladder neck to the contralateral side. Proceed with the placement of either the TVT or SPARC sling.
Placing the TVT sling. Attach the TVT introducer to the curved needle trocar on 1 end of the polypropylene sling. Insert the trocar with the tape attached into the vaginal incision and push through the retropubic space, keeping the trocar in close contact with the posterior surface of the pubic bone (FIGURES 3 and 4). Continue pushing the trocar through the urogenital diaphragm until its tip comes through the suprapubic incision on the ipsilateral side (FIGURE 5). It is important to not deviate too laterally, medially, or cephalad during trocar insertion to prevent vessel, bladder, or bowel injury. Perform a cystoscopy to rule out cystotomy. Place the second trocar in a similar manner on the opposite side. After both trocars have been pulled through their respective incisions, perform a tension test.
Placing the SPARC/abdominal TVT sling. Guide the abdominal needles through the previously marked suprapubic incision and the patient’s retropubic cavity (keeping the needle behind the pubic bone), to a finger placed in the vaginal incision (FIGURE 6). Snap the abdominal needle guides with the attached polypropylene mesh to the sling connectors (FIGURE 7). Bring the abdominal needles through the suprapubic incisions. Perform a tension test. As with the TVT sling, perform a cystoscopy after each needle placement to rule out cystotomy. Then pass the sling through the tunnel.
Testing for continence. Once the sling is in place, fill the bladder with 250 cc of water and perform a cough stress test. Adjust sling tension by pulling up on both sling arms until only a few drops of leakage are noted. It is important not to secure the sling too tightly as this may lead to urinary retention, detrusor instability, or urethral erosion. We prefer placing a hemostat between the sling tape and the urethra to avoid over tightening.
Suspending the sling arms. Remove the plastic sheaths after tension adjustment and cut the sling flush with the skin (FIGURE 8). Compared to the conventional bone-anchored slings, the newer tension-free sling devices are not anchored but instead suspended through the retropubic space. At first, the sling is held in place by friction from the opposing tissues. Over time, collagen formation fixes the mesh more strongly within the suburethral and paravaginal tissues.
