Single incision slings (SIS) are the newest generation of mid-urethral slings (MUS) used to treat stress urinary incontinence (SUI). Developed to reduce the risk of viscus injury through a shorter length and absence of passage through the retropubic space, SIS have equal short term efficacy to retropubic and transobturator slings (1). However, much of this evidence relates to the Miniarc which is no longer available. It is necessary for each device to have its own efficacy and safety data. The Therapeutic Goods Administration removed SIS from its ARTG listing in January 2018 due to lack of efficacy and safety data. In addition, its decision would have been influenced by the RANZCOG position statement on midurethral slings revised in May 2017 which recommended that single incision slings should only be performed in the context of a randomised controlled trial or where long term prospective audit was available (2). This study aims to compare the medium term efficacy and safety of 2 types of single incision slings, Altis (Coloplast) and Solyx (Boston Scientific), hypothesising both slings to be comparable over all outcomes.

We conducted an ambispective cohort study of women with SUI who had failed conservative therapy, requested surgical management and were offered a SIS. Women who had intrinsic sphincter deficiency, untreated detrusor overactivity, significant voiding dysfunction on urodynamic assessment or prior MUS surgery were not offered this surgery. Those with concurrent prolapse repair or mixed urinary incontinence were included. Data was collected at a single time point > 12 months from their index surgery including clinical examination including cough stress test, patient-reported outcome questionnaires PGI-I, ICIQ-Urinary Incontinence Short Form, Australian Pelvic Floor Questionnaire, and safety data. Institutional ethics approval and patient informed consent was obtained.
Subjective cure was defined as negative response to ICIQ Urinary Incontinence – Short Form Question 6 (leakage during coughing/sneezing and physical activity/exercise). Objective cure was defined as a negative cough stress test with a comfortably full bladder during clinical examination. Data analysis was performed using SPSS version 21.

A total of 111 women (Altis n=63, Solyx n=48) were consecutively operated on for SUI during the 5-year period (2012 - 2017). 9 patients were excluded (n=3 declined to take part, n=4 not contactable, n=2 intrinsic sphincter deficiency and part of another RCT). 102 participants (92%) were included for analysis (Altis n=60, Solyx n=42).
The mean follow-up period for the entire cohort was 32 months (range 12 – 72), with mean of 21.6 months for Altis, and 47 months for Solyx. Mean age was 53.8 years, mean BMI 26.3, and no significant differences in baseline characteristics or functional outcomes between the two groups (Table 1). 
Subjective cure (Altis 71.4% v Solyx 73.7%, p=1.00) and objective cure rates (Altis 93.9% v Solyx 89.2%, p= 0.457) for stress incontinence over the medium term showed no statistical difference, with no significant difference seen in other functional outcomes: PGI-Improvement score, ICIQ-UI Short Form total score, or treatment for overactive bladder (see Table 2). 
Mesh related adverse events were low in both groups with no significant differences seen in minor mesh exposures, minor mesh excision, or sling loosening. There was 1 total sling removal at 1 week in Altis group for significant groin pain and a retropubic sling placed at that time. A total of 4 repeat slings were performed for unsuccessful primary surgery (Altis n=2 v Solyx n=2, p=1.0). Groin pain lasting >1 week was significantly higher in the Altis group. Only 3 cases with groin pain persisted beyond 3 months, all in the Altis group. Groin pain in these 3 patients resolved at 3, 6, and 12 months respectively with analgesia and physiotherapy and all remain pain free (Table 2).

Altis and Solyx minislings appear comparable for treating stress urinary incontinence over medium-term follow-up, with a low rate of serious complications. Strengths of this study include a low loss to follow-up rate, moderate cohort size, and medium-term length of follow-up. Limitations include non-randomisation and lack of control arm.

This study provides further evidence to support the efficacy and safety of Altis and Solyx minislings for treating female stress urinary incontinence over medium term follow-up. In the current climate, device specific efficacy and safety data is essential.

Mostafa A, Lim CP, Hopper L, Madhuvrata P, Abdel-Fattah M. Single-incision mini-slings versus standard midurethral slings in surgical management of female stress urinary incontinence: an updated systematic review and meta-analysis of effectiveness and complications. Eur Urol. 2014 Feb;65(2):402-27
Position Statement on Midurethral Slings, RANZCOG (May 2017)