Molecular Processes in Stress Urinary Incontinence: A Systematic Review of Human and Animal Studies

Stress urinary incontinence (SUI) is a common and burdensome condition. Because of the large knowledge gap around the molecular processes involved in its pathophysiology, the aim of this review was to provide a systematic overview of genetic variants, gene and protein expression changes related to SUI in human and animal studies. On 5 January 2021, a systematic search was performed in Pubmed, Embase, Web of Science, and the Cochrane library. The screening process and quality assessment were performed in duplicate, using predefined inclusion criteria and different quality assessment tools for human and animal studies respectively. The extracted data were grouped in themes per outcome measure, according to their functions in cellular processes, and synthesized in a narrative review. Finally, 107 studies were included, of which 35 used animal models (rats and mice). Resulting from the most examined processes, the evidence suggests that SUI is associated with altered extracellular matrix metabolism, estrogen receptors, oxidative stress, apoptosis, inflammation, neurodegenerative processes, and muscle cell differentiation and contractility. Due to heterogeneity in the studies (e.g., in examined tissues), the precise contribution of the associated genes and proteins in relation to SUI pathophysiology remained unclear. Future research should focus on possible contributors to these alterations.

Pain after midurethral sling; the underestimated role of mesh removal

Introduction

The primary aim of this study was to evaluate the results of midurethral sling (MUS) removal in women who have pain as their single complication of MUS.

Material and methods

We performed a retrospective chart study supplemented with a cross sectional questionnaire. Women who underwent MUS removal for pain as the solitary reason for removal between 2004 and 2018 were included. Primary outcome was change in pain levels assessed by the visual analogue scale (VAS) pain score (range 0–10). Secondary outcome was the recurrence of stress urinary incontinence (SUI).

Results

Twenty-six of 31 patients returned the questionnaire. Median medical file follow-up was 12 months (range 2–66) and 25 months (range 5–104) regarding questionnaires. VAS pain score dropped from 7.8 (SD 1.9) at baseline to 4.5 (SD 3.2) at follow-up (p <.00). Seven (23%) patients were pain-free. Patients undergoing partial vaginal resection (n = 6) had a VAS pain score decrease of 4.7 (p = .02) versus 2.7 (p = .02) for complete vaginal removal (n = 14). Twenty-three (89%) patients experienced SUI at follow-up, whereof 10 (45%) reported (almost) no incidents of SUI.

Conclusions

MUS removal is a viable and safe option with a significant drop in VAS pain score in patients with chronic pain after MUS placement. A post-operative increase of SUI and a possible renewed wish for SUI treatment have to be considered. This should not be a reason to refrain from information and/or referral for surgical removal.

Urodynamic effects of prostatic urethral lift procedure for male voiding LUTS

AIMS

Primary objective is to investigate whether prostatic urethral lift (PUL) results in an improvement of urodynamic parameters that define bladder outlet obstruction (urethral resistance algorithm [URA], Schäfer grade, PdetQmax, PdetOpen).

METHODS

20 patients (main inclusion criteria: ≥ 50 years of age, BPO, IPSS ≥ 13, prostate volume ≤ 60 mL, no middle prostate lobe) were enrolled in the study and a PUL was performed. Patients underwent urodynamic investigation and filled out the IPSS and QoL before and after PUL. A paired T test was used to analyze the results.

RESULTS

The mean age was 68 years (range 55-79), mean prostate volume (TRUS) was 45 mL (range 20-59) and mean PSA was 2.0 ug/L (0.2-4.4). IPSS of the 16 patients reduced significantly (from 22.20 to 14.47, p=0.000). Qmax during pressure flow study improved significantly (from 4.5 ml/s to 7.2 ml/s, p=0.001), no significant difference was found in Qmax during free uroflowmetry. There was no significant difference found in post voiding residual. URA decreased significantly post treatment (from 52 cmH2O to 37 cmH2O, p=0.000). The Schäfer obstruction plot decreased significantly (from 3.5 to 2.6, p= 0.022). Seven patients underwent Greenlight Laser Vaporization of the prostate after the PUL due to unsatisfactory results.

CONCLUSIONS

PUL has desobstructive effects, but they seem clinically modest. The procedure improves urodynamic parameters as well as QoL in males with LUTS based on BPO. However, the mechanism how PUL leads to a remarkable symptom relieve remains unclear and cannot be explained by the desobstructive mechanisms we observed.

Association between levator ani avulsion and urinary incontinence in women: A systematic review and meta-analysis

Background

Urinary incontinence is a bothersome symptom. Although the relationship between stress urinary incontinence (SUI) and vaginal delivery is established, the pathology underlying SUI after vaginal birth remains to be elucidated.

Objectives

To determine whether levator ani muscle avulsion predisposes for SUI in women.

Search strategy

Pubmed and Embase were searched for terms and their variations “levator ani muscle avulsion” and “urinary incontinence”, from inception until 5 November 2019.

Selection criteria

Inclusion criterion: studies describing the relationship between urinary incontinence and levator ani muscle avulsion in women at least 1 year after delivery. Exclusion criterion: studies only analyzing the urethral sphincter or hiatus dimensions.

Data collection and analysis

Odds ratios were used and if not available, were calculated as means of data synthesis, adjusted odds ratios if presented by the study, random‐effects model to compute a pooled estimate.

Results

Seven studies were included, accounting for 2388 women. Comparing women with and without levator ani muscle avulsion, the overall odds ratio for SUI is 0.87 (95% confidence interval 0.56–1.34), and after adjustment for possible confounders was 0.72 (95% confidence interval 0.40–1.30).

Conclusion

There is no relationship between levator ani muscle avulsion and SUI in women.

A systematic review and meta‐analysis was conducted to evaluate the relationship between levator ani muscle avulsion and stress urinary incontinence, which could not be supported.

A New Implanted Posterior Tibial Nerve Stimulator for the Treatment of Overactive Bladder Syndrome: 3-Month Results of a Novel Therapy at a Single Center

PURPOSE

This study was designed to investigate the safety and performance of a new implantable system for tibial nerve stimulation for overactive bladder symptoms.

MATERIALS AND METHODS

A battery-free stimulation device for tibial nerve stimulation (BlueWind Medical, Herzliya, Israel) was implanted in 15 patients. Safety and efficacy assessments were done at 3 months after activation with a 3-day bladder diary, a 24-hour pad test and 2 quality of life questionnaires.

RESULTS

Two males and 13 females were enrolled in the study. Mean age was 54 years (range 19 to 72). Five of 15 patients were previously treated with percutaneous tibial nerve stimulation and 12 experienced urgency urinary incontinence. Median operative time was 34 minutes. At 3 months of followup a significant change was seen in 24-hour frequency from a mean ± SD of 11.8 ± 3.5 to 8.1 ± 2.0 times per day (p = 0.002), the number of severe urinary urgency episodes from 6.5 ± 5.1 to 2.0 ± 2.1 times per day (p = 0.002), the number of severe incontinence episodes from 2.8 ± 5.2 to 0.3 ± 0.4 episodes per day (p = 0.017), urinary loss per day from 243 ± 388 to 39 ± 55 gm (p = 0.038) and improvement in quality of life. After implantation, 3 patients received prolonged antibiotic treatment and 3 received pain medication for 1 week. In 1 patient the device was explanted due to pain and swelling suspicious for infection, although tissue cultures did not reveal a bacterial infection.

CONCLUSIONS

This novel posterior tibial nerve stimulator is safe and easy to implant with good clinical results.

Subject-Controlled, On-demand, Dorsal Genital Nerve Stimulation to Treat Urgency Urinary Incontinence; a Pilot

OBJECTIVES

To evaluate the effect of subject-controlled, on-demand, dorsal genital nerve (DGN) stimulation on non-neurogenic urgency urinary incontinence (UUI) in a domestic setting.

MATERIALS AND METHODS

Non-neurogenic patients >18 years with overactive bladder symptoms and UUI were included. Exclusion criteria were mainly stress urinary incontinence. Patients underwent 1 week of subject-controlled, on-demand, DGN stimulation, delivered by a percutaneously placed electrode near the DGN connected to an external stimulator (pulse-rate 20 Hz, pulse-width 300 μs). Patients activated the stimulator when feeling the urge to void and stimulated for 30 s. The amplitude was set at the highest tolerable level. A bladder diary including a severity score of the UUI episodes/void (scores: 0 = none, 1 = drops, 2 = dashes, 3 = soaks) and a padtest was kept 3 days prior to, during, and 3 days after the test period. The subjective improvement was also scored.

RESULTS

Seven patients (4 males/3 females) were enrolled, the mean age was 55 years (range 23-73). Six completed the test week. In the remaining patient the electrode migrated and was removed. 5/6 finalized the complete bladder diary, 1/6 recorded only the heavy incontinence episodes (score = 3). 4/6 completed the padtest. In all patients who finalized the bladder diary the number of UUI episodes decreased, in 3/5 with ≥60%. The heavy incontinence episodes (score = 3) were resolved in 2/6 patients, and improved ≥80% in the other 4. The severity score of the UUI episodes/void was improved with ≥ 60% in 3/5 patients. The mean subjective improvement was 73%.

CONCLUSION

This feasibility study indicates that subject-controlled, on-demand DGN stimulation using a percutaneously placed electrode is possible over a longer time period, in a home setting, with a positive effect on non-neurogenic overactive bladder symptoms with UUI. Although the placement is an easy procedure, it is difficult to fixate the electrode to keep it in the correct position. Improvements in hardware, like a better fixated electrode and an easy to control stimulator, are necessary to make SODGNS a treatment possibility in the future.

No primary role of ambulatory urodynamics for the management of spinal cord injury patients compared to conventional urodynamics

AIMS

Adequate urodynamic assessment of bladder behavior is essential in spinal cord injury (SCI) patients. Ambulatory urodynamics are more sensitive to detect detrusor overactivity (DO) than conventional urodynamics. The primary objective of this study was to determine the value of ambulatory urodynamics for the diagnosis of DO in SCI patients compared to conventional urodynamics.

METHODS

Twenty-seven SCI patients who were suspected of DO underwent both conventional and ambulatory urodynamics at one day. A single involuntary detrusor contraction (IDC) was defined as a detrusor pressure rise of at least 10 cmH(2)O. DO according to the ICS definition was used in addition to minimize the influence of catheter artifacts. Outcome of urodynamics was used for decisions on treatment.

RESULTS

Ambulatory urodynamics were more sensitive to diagnose IDC and DO. Conventional urodynamics had a sensitivity of 82% and specificity of 75% for DO diagnosis compared to ambulatory urodynamics. Mean maximum detrusor pressures did not differ significantly between both urodynamics. When the maximum detrusor pressure at conventional urodynamics did not exceed 40 cmH(2)O, 83% (10/12) of patients had a mean maximum detrusor pressure under 40 cmH(2)O at ambulatory urodynamics. Although the inter-individual DO diagnostic agreement was lower for ambulatory than conventional urodynamics (58%, K = 0.201 vs. 77%, K = 0552), the treatment agreement was higher for ambulatory urodynamics (58% vs. 42%).

CONCLUSIONS

Ambulatory urodynamics do not seem necessary for diagnosis and risk assessment in SCI patients suspected for DO when conventional urodynamics are done properly. The exact role of urodynamics in treatment decision remains to be determined.

Minimal invasive electrode implantation for conditional stimulation of the dorsal genital nerve in neurogenic detrusor overactivity

STUDY DESIGN

Experimental.

OBJECTIVES

Electrical stimulation of the dorsal genital nerves (DGN) suppresses involuntary detrusor contractions (IDCs) in patients with neurogenic detrusor overactivity (DO). The feasibility of minimal invasive electrode implantation near the DGN and the effectiveness of conditional stimulation to suppress IDCs at different amplitudes in spinal cord injury (SCI) patients with DO were studied.

SETTING

Radboud University Nijmegen MC, The Netherlands.

METHODS

In eight healthy volunteers, a needle electrode was inserted from both a medial and lateral-to-midline site at the level of the pubic bone. Electrode insertion was guided by the genito-anal reflex (GAR) evoked by electrical stimulation and by sensation to this stimulation. In eight SCI patients with DO, the bladder was repeatedly filled and emptied partially in between. Conditional stimulation using a needle electrode was applied when an IDC was observed at urodynamics. Different amplitudes were used during each filling. Control cystometry was carried out before electrode insertion and after stimulation.

RESULTS

The lateral implant approach was preferred, as it was easier to manoeuvre the needle along the pubic bone and fixate the needle. In SCI patients, the electrode was positioned successfully, and IDCs were suppressed (range 1-6 IDC suppressions) with conditional stimulation at maximum tolerable amplitude, except for one patient. Stimulation was less effective at lower amplitudes. Stimulation lowered the intensity of bladder sensations concomitant with IDC.

CONCLUSION

The lateral-to-midline implant approach, in combination with GAR and sensation to stimulation, is feasible for electrode implantation near the DGN in SCI patients. Conditional stimulation effectively suppresses IDCs.

Limited value of bladder sensation as a trigger for conditional neurostimulation in spinal cord injury patients

AIMS

Conditional stimulation of dorsal genital nerves suppresses undesired detrusor contractions (UDC) and consequently increases bladder capacity and prevents incontinence. No clinically applicable sensor exists for reliable bladder activity monitoring as a trigger for conditional stimulation. Primary objective of this study was to determine whether bladder sensation concomitant with UDC may be used for spinal cord injury (SCI) patients to trigger neurostimulation in daily life.

METHODS

Nineteen male and 7 female SCI patients suspected of detrusor overactivity (DO) underwent conventional and 6-hr ambulatory urodynamics. Patients were instructed to do normal daily activities and to activate event buttons of the ambulatory recorder to mark events: physical activity, bladder sensation, micturition or intermittent catheterization, and urinary incontinence. Detection rate was defined as the number of recorded bladder sensation divided by the total number of recorded UDC during ambulatory urodynamics.

RESULTS

Bladder sensation was reported by 73% of patients in daily life. Only 41% of patients had analyzable bladder sensation concomitant with UDC during ambulatory urodynamics. For ambulatory and conventional urodynamics, mean detection rates were 23% and 72%, respectively, with mean recording delays of 57 and 16 sec after UDC onset, respectively.

CONCLUSIONS

Bladder sensation only occurs in a small group of SCI patients combined with a rather low detection rate and long reaction time. Therefore, bladder sensation as a trigger for conditional stimulation does not seem to be suitable for SCI patients with DO. Reliable techniques for chronic bladder activity monitoring are a prerequisite for successful clinical application of conditional stimulation.