Meta-analysis of female stress urinary incontinence treatments with adjustable single-incision mini-slings and transobturator tension-free vaginal tape surgeries

The incidence rate of female stress urinary incontinence (SUI) in women in the United States is between 23 % and 67 % [ 1, 2]. Its risk factors include obesity and fertility, and studies have shown that when BMI increases by 5, the incidence rate of SUIrisk increases by 20 to 70 % [ 3]. Surgery has become a standard treatment for female stress urinary incontinence, and the surgical treatments can be roughly divided into six categories, namely, Marshall-Marchetti-Krantz operations (represented by the Burch operation), bladder neck suspension operations (represented by the Stamey and Raz operations), anterior vaginal wall repair operations, sling surgery, paraurethral injection, and artificial urinary sphincter [ 4]. As the operations are being improved and updated constantly, we are trying to find a treatment method that is not only effective, simple, easy to perform, with small trauma, and without long-term complications but also economical.

The SIMS-Ajust sling is a novel single-incision sling that appeared on the market in 2009 [ 5]. The patient-reported cure rate of SIMS-Ajust is between 73.9 % and 81.2 %, and its objective cure rate is between 76.8 % and 84.7 % [ 6– 8]. The study on SIMS and SMUS as a whole by Alyaa Mostafa et al. [ 9] showed that after excluding the TVT-S sling, there is no significant difference in patient-reported cure rate and objective cure rate between these two methods. SIMS has an earlier and faster postoperative recovery. However, this report only performed an overall evaluation on single-incision mini-sling operations, including Mini-Arc, Ajust, Ophira, Needleless-Contasure, TFS, and Solyx, and did not include an individualized analysis on SIMS-Ajust. In particular, there is no report on the efficacy of SIMS-Ajust. Compared with the previous report, we have included two new randomized controlled trial literatures published in June and August 2013 [ 7, 10]. In this paper, we systematically evaluate the relevant data on SIMS-Ajust and TVT-O/TOT and further confirm their safety and effectiveness, providing reliable clinical evidence.

A total of five RCT reports were selected, and the Jadad score for all five articles was three points (Table  1) [ 7, 10, 13, 14, 15] (SIMS-Ajust: n = 361, TVT-O/TOT: n = 317). A total of 13 people were lost to follow-up (SIMS-Ajust: n = 3, TVT-O/TOT: n = 10). The excluded papers and the reasons are listed in Table  2 [ 8, 16- 18].

A tension-free midurethral sling is a grade A recommendation according to the guide for stress urinary incontinence treatment [ 19]. Midurethral slings can be divided into three generations [ 20]: In 1995, Ulmsten and Petros [ 21] established retropubic tension-free vaginal tape (TVT) as the first generation of sling operations to treat urinary incontinence, and it was soon widely accepted and considered the standard operation for the treatment of female stress urinary incontinence (SUI). Although this operation has effective results, bladder perforation and other complications [ 22] prompted people to continue to search for other sling methods. The second generation of sling operations for the treatment of urinary incontinence is the transobturator TVT-O and TOT operation, and meta-analysis [ 23] showed no significant difference in efficacy between retropubic vaginal tape operation and transobturator operation. Although this operation avoids bladder perforation, postoperative thigh pain or groin pain becomes a common complication, and its incidence rate is between 1.6 % and 8.2 % [ 24, 25]. Various vaginal single-incision midurethral sling operations are the third generation of urinary incontinence operations [ 20]. Compared with traditional operations, single-incision vaginal sling operations 1) have a shorter sling, with less foreign material being inserted into human body, thereby reducing the adverse reactions to foreign material; 2) have less injury to the patient, thereby reducing possible perforation infections; 3) avoid having bladder, obturator nerves, and blood vessels in the puncture path, which is therefore safer than the traditional retropubic midurethral sling (RP-TVT) and TVT-O/TOT.

The Ajust sling is one of the single-incision vaginal slings that appeared on the market in 2009 [ 5]. Its puncture method is to use a specially designed anchor to fix the sling on the obturator membrane without letting both ends penetrate through the skin. After implantation, the tightness of the sling is adjusted through the device. In comparison, a TVT-O/TOT sling penetrates through the inner side of the thigh. Therefore, anatomically, it seems that SIMS-Ajust might have a lower cure rate or increased cases of repeat continence surgery due to its weaker anchor force. However, in reality, SIMS-Ajust has turned this factor entirely into an advantage. Our meta-analysis of the two tapes showed that SIMS-Ajust had enough anchor force in practice and with low groin pain. After comparing the five studies included in this meta-analysis, we found no significant difference in the patient-reported cure rate and objective cure rate between SIMS-Ajust and TVT-O/TOT. In addition, there is no significant difference in the comparison of the incidence rate of repeat continence surgery between SIMS-Ajust and TVT-O/TOT. The follow-up periods of both the reports included in this study are longer than 12 months. It is reasonable to say that the mid-term efficacy of SIMS-Ajust is reliable. This result indicates that although the SIMS-Ajust puncture path is short, its anchor has enough force to fix the sling in the midurethral position and cure stress urinary incontinence. In a 90-sample study by Mohamed Abdel-Fattah et al. [ 6], there were two cases of less effective slings that failed when removed, which corroborates the reliability of the anchor force from the side. The effectiveness of SIMS-Ajust is similar to the effectiveness of traditional TVT-O/TOT.

Similar to other single incision slings, the Ajust puncture does not require an incision on the inner side of the thigh or suprapubic, which reduces the risks of blood vessel, nerve, and visceral injuries. There are no cases of blood vessel or nerve injuries and other serious complications in the studies included in this meta-analysis. SIMS-Ajust has a low postoperative groin pain incidence rate. In the RCT study of Grigoriadis C. [ 7], SIMS-Ajust has no cases of postoperative groin pain, while TVT-O/TOT has five cases of postoperative groin pain, which disappeared 15 days after the operation. Therefore, in terms of the appearance of groin pain, the advantage of SIMS-Ajust is obvious. The included studies show that SIMS-Ajust has a shorter operation time than SMUS by 1–3 min, indicating that its operation is simpler and more convenient, this shorter may have no contribution to improvement of the safety of the operation. In the comparison of other complications, postoperative pain, lower urinary tract injuries, postoperative voiding difficulties, de novo urgency and/or worsening of preexisting surgery, and vaginal tape erosion are similar for both operation methods. Therefore, we can say that SIMS-Ajust is a safe operation for treating female stress urinary incontinence. Meanwhile, Dwayne Boyers et al. [ 8] performed statistical analysis on the health services and patient quality adjusted life-years (QALYs) of the same group of people in Alyaa Mostafa’s study to assess the health costs, and the results showed that because SIMS-Ajust is performed under local anesthesia, the cost is reduced according to one-year follow-up cost-effectiveness.

There are limitations of this study: (1) the number of included RCT studies is small (5), and none of them are double-blind studies; (2) observation indicators and assessment methods are different, resulting in the loss of some study data; (3) the 95 % confidence interval of some observation indicators is too wide, which requires more studies; and (4) possible gray literature may exist and lead to publication bias.

In summary, SIMS-Ajust surgical treatment for female stress urinary incontinence is safe and effective. SIMS-Ajust surgery, compared with TVT-O/TOT surgery, has the same high patient-reported and objective cure rates and low perioperative complications incidence rate. In addition, it has a short operation time and a low incidence rate of groin pain. However, as some of the studies included in this meta-analysis have a short follow up time, and meta-analysis requires continuous updates, the long-term efficacy needs further observation.

Written informed consent was obtained from the patient’s guardian/parent/next of kin for the publication of this report and any accompanying images.