Urethral bulking agents for female stress urinary incontinence

Mixed urinary incontinence: Are there effective treatments?

The aim of this debate article is to discuss whether effective treatments are available for mixed urinary incontinence (MUI). Because patients with MUI have both stress and urgency urinary incontinence (SUI and UUI) episodes and current treatment guidelines currently recommend treating the predominant symptom first, this article presents standard and emerging treatments for both SUI and UUI before discussing how well these treatments meet the medical needs of patients with MUI. Standard treatments presented include noninvasive options such as lifestyle changes and pelvic floor exercises, pharmacological agents, and surgery. Treatment of all three types of urinary incontinence (UI) is usually initiated with noninvasive options, after which treatment options diverge based on UI subtype. Multiple pharmacological agents have been developed for the treatment of UUI and overactive bladder, whereas surgery remains the standard option for SUI and stress-predominant MUI. The divide between UUI and SUI options seems to be propagated in emerging treatments, with most novel pharmacological agents still targeting UUI and even having SUI and stress-predominant MUI as exclusion criteria for participation in clinical trials. Considering that current treatment options focus almost exclusively on treating the predominant symptom of MUI and that emerging pharmacological treatments exclude patients with stress-predominant MUI during the development phase, effective treatments for MUI are lacking both in standard and emerging practice. Ideally, agents with dual mechanisms of action could provide symptom benefit for both the stress and urgency components of MUI.

The Efficacy and Mid-term Durability of Urethral Sphincter Injections of Platelet-Rich Plasma in Treatment of Female Stress Urinary Incontinence

Aims: This study investigated the therapeutic effect of repeated urethral sphincter injections of autologous platelet-rich plasma (PRP) in treatment of stress urinary incontinence (SUI) in women due to intrinsic sphincter deficiency (ISD) refractory to medical treatment or after the first anti-incontinence surgery.

Methods: Twenty-six women with SUI due to urodynamically proven ISD were prospectively enrolled. Five milliliters of PRP (2.5–5 times of the platelet concentrations in peripheral blood) were injected into the external sphincter at 5 sites, with 4 treatments at monthly interval. The primary end-point was post-treatment Global Response Assessment (GRA, scored 0–3) score after four PRP treatments. A GRA ≥ 2 was considered as a successful result. The secondary endpoints included changes in visual analog scale (VAS) of SUI and urodynamic parameters. The follow-up date was 12 months after the fourth PRP treatment.

Results: The mean age was 61.7 ± 15.3 years. The overall success rate was 50% with the post-treatment mean GRA of 1.5 ± 1.1. Complete dryness was achieved in 12 patients (46.2%) after the PRP treatment, and 7 (26.9%) kept total continence at 12 months. The mean VAS of SUI score decreased significantly from 6.4 ± 2.3 to 3.9 ± 2.3 after treatment (p < 0.001). The abdominal leak point pressure increased significantly from 117.5 ± 63.8 to 133.6 ± 61.7 cmH₂O (p = 0.045). No perioperative adverse events or severe complications occurred, except 1 (3.8%) patient reported straining to void which was self-limited.

Conclusion: Repeated urethral sphincter injections of autologous PRP are a safe procedure that provides significant reduction in the severity of female SUI and a mid-term durability, suggesting PRP treatment is effective to increase urethral sphincter resistance for female SUI.

Stress Urinary Incontinence: Slings, Single-Incision Slings, and Nonmesh Approaches

Synthetic midurethral slings offer optimal cure rates for the minimally invasive treatment of stress urinary incontinence in women. Performed via a retropubic or transobturator technique, midurethral sling approaches demonstrate comparable efficacy, with unique adverse event profiles. Single incision slings were introduced to minimize the complication of groin pain with full-length transobturator slings and enhance operative recovery. The earliest therapies for stress urinary incontinence including urethral bulking, retropubic colposuspension, and autologous sling offer alternative methods of surgical management without using synthetic mesh. These methods boast satisfactory efficacy with low rates of complications, and may be ideal for appropriately selected patients.

Transurethral versus suprapubic catheterization to test urethral function in rats

Transurethral and suprapubic catheterization have both been used to test urethral function in rats; however, it is unknown whether these methods affect urethral function or if the order of catheterization affects the results. The aim of this cross-over designed experiment was to compare the effects of catheterization methods and order on leak point pressure (LPP) testing. LPP and simultaneous external urethral sphincter electromyography (EUS EMG) were recorded in anesthetized female virgin Sprague-Dawley rats in a cross-over design to test the effects of transurethral and suprapubic catheterization. There was no significant difference in peak bladder pressure during LPP testing whether measured with a transurethral or suprapubic catheter. There was no significant difference in peak bladder pressure between the first and second catheter insertions. However, peak EMG firing rate, as well as peak EMG amplitude and EMG amplitude difference between peak and baseline were significantly higher after the first catheter insertion compared to the second insertion, regardless of the catheter method. Our results suggest that route of catheterization does not alter urethral function, e.g. create a functional partial outlet obstruction. Either catheterization method could be used for LPP and/or EUS EMG testing in rats.

Use of bioactive extracellular matrix fragments as a urethral bulking agent to treat stress urinary incontinence

Injection of urethral bulking agents is a low-risk, minimally invasive surgical procedure to treat stress urinary incontinence (SUI). In this study, we developed a promising injectable bulking agent comprising extracellular matrix fragments of adipose-derived stem cell sheets (ADSC ECM) and investigated its effectiveness in urethral bulking therapy. The structural integrity and proteins of ADSC sheet ECM were well retained in decellularized ADSC ECM fragments. To locate transplanted ADSC ECM fragments, they were labeled with ultrasmall super-paramagnetic iron oxide nanoparticles, which enabled in vivo monitoring after implantation in a SUI rat model for up to 4 weeks. When ADSC ECM fragments were injected into the rat urethra, they became fully integrated with the surrounding tissue within 1 week. Four weeks after transplantation, host cells had regenerated within the ADSC ECM fragment injection area. Moreover, new smooth muscle tissue had formed around the ADSC ECM fragments, as confirmed by positive staining of myosin. These results indicate that injection of ECM fragments may be a promising minimally invasive approach for treating SUI.

Rapid and precise delivery of cells in the urethral sphincter complex by a novel needle-free waterjet technology

OBJECTIVES

To investigate the therapy of stress urinary incontinence in a preclinical setting cells were injected into the urethrae of minipigs; however, cells injected by William's needle were frequently misplaced or lost; thus, we investigated if needle-free cell injections using a novel waterjet technology facilitates precise injections in the urethral sphincter complex.

MATERIALS AND METHODS

Porcine adipose tissue-derived stromal cells (pADSCs) were isolated from boars, expanded, labelled, and injected in the sphincter of female pigs by waterjet employing two different protocols. After incubation for 15 min or 3 days, the urethrae of the pigs were examined. Injected cells were visualised by imaging and fluorescence microscopy of tissue sections. DNA of injected male cells was verified by polymerase chain reaction (PCR) of the sex-determining region (SRY) gene. Cell injections by William's needle served as controls.

RESULTS

The new waterjet technology delivered pADSCs faster and with better on-site precision than the needle injections. Bleeding during or after waterjet injection or other adverse effects, such as swelling or urinary retention, were not observed. Morphologically intact pADSCs were detected in the urethrae of all pigs treated by waterjet. SRY-PCR of chromosomal DNA and detection of recombinant green fluorescent protein verified the injection of viable cells. In contrast, three of four pigs injected by William's needle displayed no or misplaced cells.

CONCLUSION

Transurethral injection of viable pADSCs by waterjet is a simple, fast, precise, and yet gentle new technology. This is the first proof-of-principle concept study providing evidence that a waterjet injects intact cells exactly in the tissue targeted in a preclinical in vivo situation. To further explore the clinical potential of the waterjet technology longer follow-up, as well as incontinence models have to be studied.

Urethral bulking agents: a retrospective review of primary versus salvage procedure outcomes

PURPOSE

Urethral bulking agents (UBA) have traditionally been offered as salvage procedures for recurrent stress urinary incontinence (SUI). We compare the success of UBA in patients that had undergone a previous procedure for SUI (Salvage-UBA) to the SUI surgery naïve (Primary-UBA). We hypothesised a positive effect in both Primary and Salvage-UBA with potentially poorer rates of response in the salvage group.

METHODS

Retrospective case series of patients having their first UBA (2010-2018). Primary outcome was to assess any difference in patient reported success between groups. Patient-reported improvement was assessed on a 4-point scale: 'cured, improved, no change, worse' and treatment 'success' defined as 'cured' or 'improved'. A multivariate analysis, adjusting for plausible differences between groups, was undertaken in IBM SPSS Statistics (2016).

RESULTS

135 Primary-UBA and 38 Salvage-UBA were performed. Complete follow-up was obtained for 114 patients (66%): 86 Primary and 28 Salvage. Median follow-up time: 33 months. In 2012, 47% (8/17) of all UBA were Salvage-UBA, whilst in 2018, the majority were Primary-UBA (92%, 46/50). Success was not significantly different between Salvage-UBA 75% (21/28) versus Primary-UBA 67% (58/86) (Wald χ² = 0.687, df = 1, p = 0.407). Top-up rates were similar: 14% (n = 4/28, Salvage-UBA) versus 15% (n = 13/86, Primary-UBA) (χ² = 0.011, df = 1, p = 0.914).

CONCLUSION

The number of women opting for UBA has increased substantially. No significant differences were noted for success with Salvage-UBA compared to Primary-UBA.

Is the anchor matter? A short-term follow-up of the effect of mini-invasive mid urethra sling without anchor for urinary incontinence women

OBJECTIVE

Stress urinary incontinence (SUI) is a common disease in aged women, and some of them need surgical correction. Recently, the mid-urethral sling is an accepted surgical approach for SUI. However, complication may occur in this surgery, and some of them are needle-related. Therefore, the needleless system may diminish this-type complication.

MATERIALS AND METHODS

We conducted a retrospective study to evaluate the feasibility of women with SUI undergoing needleless sling surgery in 2017. Assessments were performed by two independent special urogynecologists before, during and post operation periods. We used a category-time-site-pain code following the International Continence Society and International Urogynecological Association (ICS/IUGA) Complication Classification Code (CCC) guidelines.

RESULTS

Thirty-eight women were analyzed. The characteristics of the patients were 66.3 ± 12.8 years old (mean ± standard deviation) of age, 2.8 ± 1.2 of parity, and 25.6 ± 4.2 kg/m² of body mass index. All had history of vaginal delivery for term. The objective cure rate at 2- and 4-week follow-up was 97.4% (n = 37) and 94.7% (n = 36), respectively. The subjective cure rate at 2- and 4-week follow-up was both 89.5% (n = 34). Both objective and subjective cure rates remained constant and similar to the end of 4 weeks. There were 6 patients (15.8%) who had complications according to ICS/IUGA CCC guidelines.

CONCLUSION

This needleless mid-urethral sling procedure seemed to be feasible in the management of women with SUI in this small series and short-term follow-up study, suggesting that a further prospective, randomized, comparative study with other tension-free procedures and mini-sling systems can be conducted.