Midurethral slings are currently composed mostly of polypropylene (PP). PP has been proven to cause fewer complications, mainly due to the fact that it is inert, not sifting, not allergic, and not causing inflammatory reactions. Nevertheless, common complications related to PP tapes are postoperative voiding problems, tape erosions in the vagina or adjacent organs, voiding problems, recurrent urinary infections, etc. Therefore, it is of paramount value to discover novel materials with different and if possible minimal complication profiles in the management of stress urinary incontinence (SUI). It seems that polyvinyldihydrofthoride (PVDF) is theoretically a useful alternative in SUI treatment. PVDF has been massively used in other prosthetic fields of medicine (cardiac valves, orthopedics) and it is related to reduced rates of rejection, erosion, inflammatory reactions, pain or dysfunction (1,2).
The aim of the study is to compare the effectiveness and safety of PP and PVDF transobturator tapes (TOT) for the treatment of female SUI.

This is a clinical, cross-sectional, single-centre study in an academic urogynecologic unit. As no relevant literature exists, a convenience sample of two groups from 30 patients each was considered as adequate for a non-inferiority study. Sixty female patients with SUI who consecutively underwent TOT surgery with PVDF (group PVDF: 30 patients) or PP (group PP: 30 patients) sling between January 2018 and December 2021. Inclusion criteria were: (a) women over the age of 18, (b) Greek speakers, and (c) women with at least moderate SUI/MUI. Informed consent was obtained as appropriately by all the participants and the study protocol was approved by the Ethics Committee of the hospital. All patients before surgery had a clinical examination and a standardized cough test. Symptoms were measured with the use of the ICIQ-UI (short form) questionnaire and the patients had a full urodynamics investigation (uroflowmetry, filling cystometry, pressure-flow studies, and urethral profilometry). All patients had pelvic floor sonographic evaluation (PFUS: urethral mobility assessment, bladder wall thickness (BWT) assessment). All patients had a transobturator mid-urethral sling (PVDF or PP) with a standardized inside-out technique. Then, both groups were examined 6 months post-operatively with: (a) clinical exam and standardized stress test, (b) check for tape erosions, (c) urethral mobility and sling mobility, (d) PGI-I and PGI-S score. Urethral and sling mobility were analyzed according to a standardized and reproducible method described by Schaer et al (1,2). Statistical analysis was performed with MedCalc. An independent paired t-test was used to compare the pre- and post-operative results of the PVDF and PP groups. Statistical significance was defined as p 0.05.

60 patients were recruited. The PVDF group mean age was 61.2±8.0 years and the PP group was 61.6±5.9 years (p=0.84). The mean BMI in the PVDF group was 29.3±3.4 and in the PP group was 29.5±3.3 kg/m2 (p=0.89). The mean parity was 2.1±1.0 for PVDF group and 2.1±0.8 for PP group (p-value: 0.45). In PVDF group 24/30 (80%) and in PP group 22/30 (73%) of patients underwent prolapse surgery simultaneously (p=0.542). Pre-operatively, 83% of the patients in PVDF group and 80% of the PP group had moderate or severe SUI (p=0.866). The main urethral length was 3.33±0.41cm for PVDF group and 3,43±0,35cm for PP group (p=0.19). Pre-operatively, mean Bladder Neck Mobility (BN-MOB) in PVDF and PP groups was 1.26±0.36 and 1.20±0.35, respectively (p=0.48).
In the 6 months examination, 28/30 (93.3%) of PVDF group and 25/30 (83.3%) of PP group had a negative stress test (p=0.644). No tape erosion into the vagina was identified in PVDF group, although in PP group there was an incidence of erosion (1/30, 3.3%). No post-operative pain or dyspareunia was reported by any of the patients, and there was no pathological post-void residual (PVR) in both groups. PVDF group had a statistically significant better PGI-S score than PP group (1.37 vs 2.03, p=0.02) and there wasn’t any statistically significant difference in PGI-S score between the two groups. The mean distance of the sling from the inside urethra orifice was 1.9±0.4cm in PVDF group and 1.9±0.3cm in PP group (p=0.35). The patients in the PVDF group exhibit higher but not statistically significant decrease of urethral mobility post-operatively (0.63±0.34cm vs 0.49±0.56cm, p=0.22). Also, we found a higher but not statistically significant sling mobility in PVDF group (0.82±0.69 vs 0.71±0.24 cm) (p=0.41).

Incontinence surgery is facing a challenge due to the constant improvement of techniques and materials used. Initial approaches with polypropylene meshes of various types and weaves had the result that numerous varieties of materials were gradually abandoned from clinical practice because of increased complications or decreased success rates. Macroporous type I PP tapes were established as the ideal type of material for suburethral incontinence operations. Nevertheless, the inherent disadvantages of PP tapes are the erosion, the migration, and the diminishing of the successful outcome over time. This study provides an initial insight into the use of PVDF tapes. Early experience seems to be promising, with results comparable to those of the PP tapes.

This is one of the first studies where PP slings are compared to PVDF slings for the surgical treatment of SUI. Initial experience with the use of PVDF tapes as sub-urethral slings appears to be satisfactory in terms of safety, functionality, and effectivity. Large, prospective, non-inferiority studies have to be performed in order to demystify the exact efficacy of these tapes in the field of pelvic surgery.

Schaer G.N., Koechli O.R., Schuessler B., Haller U.. Perineal ultrasound for evaluating the bladder neck in urinary stress incontinence. Obstet Gynecol 1995;85: 224–229.
Peschers U.M., Schaer G.N., DeLancey J.O., Schuessler B.. Levator ani function before and after childbirth. Br J Obstet Gynaecol 1997;104: 1004–1008.

Continence 2S2 (2022) 100345
DOI: 10.1016/j.cont.2022.100345