Safety and Efficacy of Single Incision Sling Versus Midurethral Sling in the Treatment of Stress Urinary Incontinence: A Randomized Controlled Trial
Authors: Huser Martin , Hudecek Robert , Belkov Ivan , Horvath Ivan , Jarkovsky Jiri , Tvarozek Samuel 
Published: May 2023

The midurethral sling (MUS) is the criterion standard for SUI treatment in women, with a third-generation MUS utilizing a single vaginal incision (single-incision sling [SIS]) becoming a means for preventing postoperative groin pain associated (rarely) with transobturator sling. However, SIS requires additional long-term evidence of effectiveness through randomized trials comparing their use with MUS. The goal of this study was an evaluation of safety and efficacy of the use of Ophira SIS as compared with inside-out full-length transobturator tape (TOT) sling (MUS) use over long-term follow-up. Primary randomized controlled trial outcomes included SUI objective cure rate evaluations 4 years after MUS operation. Secondary study end points included quality of life, early and late operative complications, subjective cure, recurrent surgery need, and urgency incontinence occurrence.

This study, which took place at the Czech tertiary referral Brno University Hospital Urogynecology Center, was a randomized noninferiority controlled trial held from January 2015 through December 2019. Women with urodynamic SUI, as confirmed via positive cough test during cystometry, were included in this nonblinded study. Exclusion criteria were as follows: urgency or predominant urgency incontinence, pelvic organ prolapse stage 2 or greater, intrinsic sphincter deficiency, previous SUI surgery, previous pelvic organ prolapse surgery, and presence of additional organ pathology. The International Consultation on Incontinence Questionnaire—Short Form was completed to assess symptom impact on patient quality of life. Baseline patient characteristics including body mass index, age, and parity were recorded, and written informed consent for enrollment in the study was collected from all patients.

Randomization occurred via the envelope technique (sequentially numbered opaque envelopes distributed at the time of surgery) to assign patients to an SIS anti-incontinence procedure or MUS. The SIS procedures used Ophira (Promedon) surgical kits, and the MUS procedure used the inside-out Gynecare TVT Obturator System (Ethicon). Senior surgeons with more than 200 previous MUS or SIS procedures performed the operations. The authors assumed a minimum sample size of 64 patients in each group was needed to identify noninferiority.

An independent clinician performed follow-up visits at 4 years postoperation, including an evaluation of objective cure (absence of urinary leakage) as primary study outcome. Subjective cure included the International Consultation on Incontinence Questionnaire—Short Form tiers of 1 (“very much improved),” 2 (“much improved),” or 3 (“improved).” A total of 192 eligible patients participated, with 24 declining randomization for a total of 168 patients (87.5%) being randomized into SIS (n = 84) and MUS groups (n = 84). From these, full completion of the 4-year follow-up took place for 66 SIS patients (78.6%) and 64 MUS patients (76.2%). The results of the analysis indicated that the MUS and SIS groups demonstrated no statistically significant differences in cure rates at 4 years after surgery, with objective (86.4% vs 84.4%) and subjective (83.3% vs 81.3%) cure rates, respectively. The study was not powered to determine differences in secondary outcomes, but a similar proportion in both groups required reoperation for recurrent SUI (6.9%), and no significant pain outcomes were observed in either group.

A strength of the trial is its thorough standardization, as all procedures were implemented by the same urogynecology surgeons with ample experience. The randomized study design coupled with long-term follow-up provided high-quality data. A limitation of the trial is the lack of blinding of the patient (via absence or presence of additional MUS incisions), postoperative assessments were done by unblinded members of the team, and a portion of both groups was lost to follow-up. A similar, but not insignificant, portion of both treatment groups was lost to follow-up, introducing risk of selection bias. Finally, not all SISs on the market can be assumed to be equal because of differing materials, anchoring systems, and insertion techniques, and the specific device used in this study is not commercially available in the United States.

The findings of this study are that the Ophira SIS had comparable curative rates to transobturator MUS among women undergoing SUI surgery. Additional external validation studies are necessary. However, these results can be included in future meta-analyses for fostering understanding of SUI management via SIS systems.