Retropubic polypropylene tape sling

Petros and Ulmsten developed tension‐free vaginal tape (TVT), the first minimally invasive retropubic polypropylene tape (RPT) sling procedure performed under local anesthesia for SUI. The TVT procedure begins with the injection of local anesthetic abdominally and vaginally along bilateral trocar paths. Through a 1.5 cm vaginal incision, bilateral periurethral dissection is performed to the inferior aspect of the pubic symphysis. Trocar needles with attached prolene mesh tape, covered by a plastic sheath, are inserted into the vaginal incision and then passed through the urogenital diaphragm, into the retropubic space just deep to the pubic bone and then out through the suprapubic area. Cystoscopy is routinely performed post procedure to rule out bladder perforations. After the tape is placed at the mid urethra and adjusted with a cough test to ensure continence, the plastic sheath is removed and incisions are closed [5, 6].

Initial 3‐year data demonstrated that Petros and Ulmsten’s new RPT sling resulted in 86% cure rates and 11% improvement rates [6]. Long‐term results observed by Nilsson et al. over an 11.5‐year period reported subjective cure rates of 77% and improvement rates of 20% [7]. Randomized controlled trial evidence suggests that TVT has a similar cure rate to colposuspension [8, 9]. Since 1998, several RPT slings have been marketed as either transvaginal or suprapubic needle insertion techniques.

Although the reported efficacy of RPT slings was promising, the blind passage of trocar needles into the retropubic space created a new set of potential complications. A review by Atherton et al. showed that RPT procedures were associated with a 0.2–1% postoperative urinary retention rate, a 3–4% risk of bladder, urethral, or intestinal perforation, and a 1–2.5% risk of major vessel and nerve injury and hematoma in the retropubic space [10]. The incidence of these complications, although infrequent, led surgeons to further explore modifications and improvements in minimally invasive urinary incontinence surgical procedures.

Transobturator polypropylene tape sling

In an attempt to avoid rare, but unwanted, complications associated with the retropubic trocar needle passage, Delorme developed the “outside‐in” transobturator approach to polypropylene sling placement in 2002. By avoiding the retropubic space with trocar passage, the transobturator approach avoids vascular, bowel, and bladder injury while maintaining proper midurethral support [11]. Transobturator tape (TOT) slings involve insertion of trocars around the ishiopubic ramus through the obturator membrane and out through a 1.5 cm midline vaginal incision. After loading the tape onto the trocar, the sling is positioned for midurethral support. In 2004, De Leval reported on a modification of the TOT procedure whereby the trocar was passed “inside‐out” from the vaginal incision to the groin incision [12]. Other than the trocar passage technique, this “inside‐out” TOT sling is similar to the “outside‐in” TOT procedure where the polypropylene tape is positioned at the mid urethra and extends to the obturator space and groin incisions.

Initial TOT sling cure or improvement rates have been shown to be 90% effective, which was comparable to the RPT sling [13–15]. Several other studies have supported the transobturator method and demonstrated TOT slings to be as efficacious as RPT slings [16–22]. Compared to RPT slings, the TOT procedure demonstrates minimal risk of bladder perforation and bowel injury; however, reports of subjective groin pain, possibly related to obturator nerve compression or muscle irritation, have been associated with TOT slings [20]. De novo urgency rates also appear to be less after a TOT sling compared to a RPT sling. Botros et al. found decreased de novo urgency rate with TOT: 8% for TOT versus 33% for transvaginal RPT and 17% for suprapubic RPT [23].

Single‐incision sling

Soon after the introduction of the TOT slings, engineers began designing the next generation of midurethral slings; the single‐incision sling (SIS). Their goal was to mimic the safety and efficacy of traditional RPT and TOT slings, yet lower the complication rate and achieve a better patient experience. The idea was to create a sling that reduced morbidity by avoiding the passage of trocars through the retropubic or transobturator space (and thus limiting injury to major organs), reduced operative time, limited external incisions, minimized anesthesia and postoperative pain, and afforded the possible option of office‐based placement.

There have been seven different SISs introduced to the market since 2006. All of the devices are placed via a single vaginal incision and are made of type 1 uncoated polypropylene mesh; however, each SIS device is unique, and they are not interchangeable products. The SISs differ in sling length, trajectory pathway, delivery device, fixation method, and fixation location (Table 160.1). Because of these significant differences, categorizing all SISs as a group is inappropriate and each SIS should be evaluated on its own merits.

The European Association of Urology 2014 guidelines on the treatment of SUI critically analyzed the data on SIS [24]. Level 1b evidence suggests that SISs are just as efficacious as RPT or TOT at 18 months, but that TVT‐Secur is less effective than conventional midurethral slings at medium‐term follow‐up. Although blood loss and postoperative pain are lower for SIS compared to RPT and TOT, other adverse outcomes cannot be fully assessed (Table 160.2). In addition, not all SIS devices have been subjected to randomized controlled trial evaluation and it may be unsafe to assume that they are collectively technically similar devices. Although results to date are promising, further long‐term efficacy data on SIS are needed. In addition, appropriate patient selection needs further study, as most SIS studies have been reserved for women without prior anti‐incontinence surgery or intrinsic sphincter deficiency.

Contraindications to SIS include: coagulopathy, pregnancy or planned pregnancy, renal insufficiency, immune compromise, and urinary tract infection or obstruction.

On January 4, 2012, the US Food and Drug Administration (FDA) ordered SIS manufacturers to complete postmarket surveillance studies of their products (522 Orders). The FDA’s orders came after considering reports of adverse events from manufacturers, physicians, and patients; the September 2011 meeting of the Obstetrics‐Gynecology Devices Panel meeting at the FDA; and a critical evaluation of the literature. Manufacturers were not only required to submit study plans to the FDA that address safety and efficacy concerns of SIS for SUI, but also to conduct premarket studies comparing SIS to traditional midurethral slings. On June 4, 2012 the first SIS (TVT‐Secur™, Ethicon Women’s Health & Urology, Somerville, NJ, USA) was voluntarily removed from the market due to concerns over commercial viability in light of changing market dynamics and not over safety or efficacy. Subsequently two other SIS devices (MiniArc™, American Medical Systems Inc., Minnetonka, MN, USA and Ajust™, CR Bard Inc., Murray Hill, NJ, USA) have also been voluntarily withdrawn from the market. The four remaining SIS manufacturers are complying with the FDA 522 Orders and beginning their comparative studies on SIS efficacy and safety.

Over the years, data have emerged regarding the safety and efficacy of each SIS. All of the SIS devices have demonstrated minimal invasiveness with less surgical dissection, shorter procedure time, and less attendant morbidity; however, the long‐term results regarding efficacy are now starting to emerge [25–27].