SACRAL NERVE STIMULATION FOR TREATMENT OF REFRACTORY URINARY URGE INCONTINENCE

[Invasive neurostimulation in neuro-urology: state of the art]

Modulation or stimulation of the nerves supplying the lower urinary tract is a possible treatment option for dysfunction of the lower urinary tract, pelvic floor and rectum if conservative or minimally invasive treatment approaches fail. This overview shows the possibilities and limitations of sacral neuromodulation, sacral deafferentation with sacral anterior root stimulation and conus deafferentation.Sacral neuromodulation (SNM) is a procedure for the treatment of refractory pelvic floor dysfunction of various origins (idiopathic, neurogenic or post-operative), such as overactive bladder, non-obstructive retention and faecal incontinence. A particular advantage of SNM is the possibility of prior test stimulation with a high prognostic value. The procedure is minimally invasive, reversible and associated with relatively low morbidity rates.Following the introduction of MRI-compatible SNM systems, there has been renewed interest in the treatment of neurogenic bladder dysfunction. A recent meta-analysis reports similar success rates as in the idiopathic patient population.Sacral deafferentation with implantation of a sacral anterior root stimulator (SARS/SDAF) is an excellent therapeutic option for patients with spinal cord injury, which can significantly improve the quality of life of those affected and, in addition to treating neurogenic lower urinary tract dysfunction, can also have a positive effect on neurogenic bowel dysfunction, neurogenic sexual dysfunction or autonomic dysreflexia. If conservative or minimally invasive treatment fails, it is crucial for the success of this procedure to consider SDAF/SARS at an early stage in order to avoid irreversible organic damage.Conus deafferentation (KDAF) is a less invasive surgical treatment option for patients with spinal cord injury for whom sacral deafferentation would be indicated but who would not benefit from the simultaneous implantation of a sacral anterior root stimulator. In principle, these patients also have the option of being subsequently treated with an extradural implant and thus utilising the advantages of anterior root stimulation. Indications for KDAF are autonomic dysreflexia, therapy-refractory detrusor overactivity, recurrent urinary tract infections, urinary incontinence and spasticity triggered by detrusor overactivity. With KDAF, we have a safe and efficient procedure with great potential for improving the spectrum of paraplegiological and neuro-urological treatment.

Tibial Nerve Stimulation for Urge Urinary Incontinence and Overactive Bladder: Narrative Review of Randomized Controlled Trials and Applicability to Implantable Devices

The tibial nerve is an established target for neuromodulation in the management of overactive bladder (OAB) and its associated symptoms, including urge urinary incontinence (UUI). Technologies are currently available to deliver tibial nerve stimulation (TNS) through percutaneous devices or through implantable devices. The benefits and safety of percutaneous TNS have led to it as a guideline-recommended therapy. However, patient compliance is limited by the burden of weekly office visits and the need for maintenance treatments. Further, insurance often only covers a limited number of lifetime visits for percutaneous TNS. These factors and others have led to the development, study, and utilization of implantable TNS devices. Implantable TNS devices deliver the same therapeutic mechanism of action for nerve stimulation with a permanent implanted device that provides at-home stimulation rather than in-office therapy delivery. Additionally, there is an added potential for dynamic and patient-centered stimulation. There is a large body of high-quality evidence published for TNS, including numerous randomized controlled trials published on percutaneous TNS which have consistently demonstrated superior efficacy to sham and similar efficacy to that of anticholinergic medications. Percutaneous TNS also performs better than conservative therapy including pelvic floor muscle training. The percutaneous and implantable approaches deliver nerve stimulation to the same target nerve, using the same mechanism of action. Therefore, data from randomized trials of percutaneous TNS are informative for implantable TNS devices. At the time of this article's publication, at least two implantable TNS devices have received marketing authorization from the Food and Drug Administration (FDA). The objective of this review is to discuss the mechanism of action for TNS and summarize the published literature from clinical trials of percutaneous TNS as a foundation of high-quality evidence for implantable devices targeting the tibial nerve.

Outcomes of sequential third-line therapies in patients with refractory overactive bladder

INTRODUCTION

Sacral neuromodulation (SNM) and onabotulinumtoxinA (BoNTA) injection are third-line therapies for overactive bladder (OAB). Although the efficacy of each third-line treatment has been well established in clinical trials, there is far less information about performing one third-line therapy after the other. Our aim is thus to investigate the outcomes of post-SNM BoNTA and post-BoNTA SNM as "second" third-line treatments.

METHODS

We retrospectively reviewed all OAB patients who had both SNM and BoNTA between 2013 and 2022. The primary endpoint was the response rates (>50% improvements) of the second third-line treatments. Secondary endpoints were the proportion of the patients who achieved total dry, the duration of treatments of patients who had significant responses, and risk factors that are associated with treatment response or duration of treatments.

RESULTS

A total of 172 patients had two third-line therapies. There were 104 patients who had post-SNM BoNTA and 68 patients who had post-BoNTA SNM. In the post-SNM BoNTA group, 62.5% (65/104) had significant responses after BoNTA treatment. In the post-BoNTA SNM group, 61.8% (44/68) had significant responses after SNM treatment. The proportions of patients who became dry were 21.2% and 23.5%, respectively. In the post-SNM BoNTA group, spinal pathology is associated with a lower probability of a significant response (48.9% vs. 73.7%, p-value = 0.0105).

CONCLUSIONS

BoNTA or SNM remains a viable option for refractory OAB after patients fail from one another. Spinal pathology is associated with a poorer response of post-SNM BoNTA.

Fluid intake behavior in women with refractory overactive bladder undergoing third line therapy

INTRODUCTION AND OBJECTIVES

Fluid intake has been shown to be related to urinary symptoms, but no studies to date have investigated the effect of fluid intake on urinary symptoms in women with refractory overactive bladder (OAB). As this group of women are considered to have a possible unique pathophysiologic mechanism of OAB, we investigated the relationship between fluid intake, fluid intake behavior, and urinary symptoms in women with refractory OAB.

METHODS

A prospective cross-sectional study of women with refractory OAB was conducted by assessing the relationship between fluid intake and lower urinary tract symptoms (LUTS) in women undergoing third line OAB therapies. Fluid intake and behavior were measured by the questionnaire based voiding diary and urinary symptoms were measured by the International Consultation on Incontinence Questionnaire for Female Lower Urinary Tract Symptoms (ICIQ-FLUTS). The relationship between fluid intake and symptom severity was assessed using Spearman's rank correlation and χ2  tests.

RESULTS

Of the 126 individuals undergoing third line therapy for OAB, 60 (48%) underwent intradetrusor onabotulinumtoxinA injection (BTX) injection, 42 (33%) peripheral tibial nerve stimulation, and 24 (19%) sacral neuromodulation. The mean total daily fluid intake was 2567.0 ± SD 1292.4 mL and did not differ significantly across treatment groups. Total fluid intake was weakly correlated with worse filling-type LUTS (r = 0.241, p = 0.007), and there was no relationship between LUTS and caffeinated fluid intake. Half (52%) of the subjects reported current fluid restricting behavior to control urinary symptoms, but this behavior was not correlated with LUTS severity (all p > 0.05). Patients that currently use tobacco have greater LUTS (current = 25.8 ± SD 9.5, former = 14.8 ± SD 6.1, never = 15.0 ± SD 6.1; p < 0.001). BMI was also positively correlated with worse incontinence symptoms (r = 0.351, p < 0.001).

CONCLUSIONS

Fluid intake along with other lifestyle factors, including tobacco use and weight, are minimally related to the symptomatology seen in women with refractory OAB. Further studies are needed to assess if behaviors change during treatment with third line therapies, and if these behavioral changes may affect treatment response.

Real-life after sacral nerve modulation implantation: Rate, reasons, and risk factors for mid-term follow-up discontinuation

OBJECTIVES

To evaluate follow-up after implantation of a sacral nerve modulation implantable pulse generator (IPG) and to investigate the reasons and risk factors for follow-up discontinuation.

MATERIALS AND METHODS

All patients who underwent an IPG implantation to treat lower urinary tract symptoms between 2014-2019 within 6 hospital centers located in the district of "Hauts-de-France" (France) were systematically called during the year 2020 for a standardized (tele)consultation. Patients were divided into 3 distinct profiles according to the regularity of their 5-year postoperative follow-up: "Regular follow-up", "Irregular follow-up" and "Lost to follow-up". The primary outcome was the change in the annual proportion of the 3 follow-up profiles over the 5 years following IPG implantation. As secondary outcomes we described the reasons reported for follow-up discontinuation and looked for risk factors associated with.

RESULTS

Overall, 259 patients were included. At the time of data collection, after a mean follow-up of 28.4 (± 19.8) months, 139 patients (53.7%) had a "Regular follow-up", 54 (20.8%) had an "Irregular follow-up" and 66 (25.5%) were "Lost to follow-up". The proportion of patients with a "Regular follow-up" decreased year by year, representing only 46.2% of patients at five-years. 175 patients (67.6%) underwent a standardized (tele)consultation. In multivariate analysis, only "lack of knowledge of the follow-up protocol" was statistically associated with follow-up discontinuation (OR=5.16; 95% CI [2.12-13.57]).

CONCLUSION

The proportion of patients followed up after IPG implantation decreased steadily over the years, often related to a lack of therapeutic education.

LEVEL OF EVIDENCE: 4

[Functional-neurosurgical treatment options for functional pelvic floor disorders : Value of sacral neuromodulation]

BACKGROUND

Sacral neuromodulation is an established minimally invasive therapy indicated for the treatment of functional pelvic floor disorders. While it received its original US Food and Drug Administration (FDA) approval for the treatment of overactive bladder symptoms, it is now regarded as a therapeutic option to treat both urinary/fecal incontinence and retention. In addition, it has proven to be a valuable tool in the treatment of chronic pelvic pain, and preliminary results indicate a potential to elicit improvements in sexual functioning.

OBJECTIVE

This article serves to provide a summary of the therapy and its applications.

METHOD

Selective literature review.

RESULTS

Sacral neuromodulation implants allow for the controlled shifting of the autonomic control of bladder and rectum towards an inhibition or facilitation of voiding, dependent on the patient's needs and under the patient's control. At the same time and depending on the applied stimulation, the implants can interfere with the nerve's conduction of pain signals. This makes them a therapeutic option for pelvic pain that fails to respond to conventional treatment. Finally, there have been first reports suggesting improvements in sexual dysfunction under sacral neuromodulation, thus, potentially opening up a new line of therapy for those disorders.

DISCUSSION

Sacral neuromodulation is a flexible and efficient form of therapy for functional disorders of the pelvic floor. Specifically, the same intervention can treat seemingly contradictory disorders such as urinary/fecal incontinence and retention as well as chronic pain.

Rationale and design of an implant procedure and pivotal study to evaluate safety and effectiveness of Medtronic's tibial neuromodulation device

Percutaneous tibial neuromodulation is a medical guideline recommended therapy for treating symptoms of overactive bladder. Stimulation is delivered to the tibial nerve via a thin needle placed percutaneously for 30 min once a week for 12-weeks, and monthly thereafter. Studies have shown that this therapy can effectively relieve symptoms of overactive bladder; however, the frequent office visits present a barrier to patients and can impact therapy effectiveness. To mitigate the burden of frequent clinic visits, small implantable devices are being developed to deliver tibial neuromodulation. These devices are implanted during a single minimally invasive procedure and deliver stimulation intermittently, similar to percutaneous tibial neuromodulation. Here, we describe the implant procedure and design of a pivotal study evaluating the safety and effectiveness for an implantable tibial neuromodulation device. The Evaluation of Implantable Tibial Neuromodulation (TITAN 2) pivotal study is a prospective, multicenter, investigational device exemption study being conducted at up to 30 sites in the United States and enrolling subjects with symptoms of overactive bladder.

Five-year Results from the Prospective, Multicenter, Observational SOUNDS Study of Patients with Overactive Bladder Treated with the InterStim System for Sacral Neuromodulation

BACKGROUND

Although sacral neuromodulation (SNM) for overactive bladder (OAB) is an established therapy, there is a lack of high-quality, long-term data on real-life practice.

OBJECTIVE

To report on real-life therapeutic effectiveness, quality of life (QoL), disease severity, and safety as well as patient-reported symptom bother after approximately 5 yr of follow-up.

DESIGN, SETTING, AND PARTICIPANTS

A total of 291 OAB patients were enrolled at 25 French sites according to local standard of care. Sacral neuromOdUlation with InterStim therapy for intractable lower uriNary tract DySfunctions (SOUNDS) enrolled both de novo and replacement patients, and a total of 229 patients were permanently implanted.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Over the course of the study, patients were followed up six times with two follow-ups in the year after implantation and annually thereafter. Of the patients, 154 completed the final follow-up after a mean of 57.7 ± 3.9 mo.

RESULTS AND LIMITATIONS

The mean number of daily leaks in urinary urge incontinence (UI) patients was reduced from 4.4 ± 3.3 at baseline to 1.8 ± 2.6 after 5 yr in de novo and from 5.4 ± 4.9 to 2.2 ± 3.0 in replacement patients (both p < 0.001). Likewise, the number of voids in urinary frequency patients was reduced compared with baseline (de novo: reduced from 12.6 ± 4.0 [baseline] to 9.6 ± 4.3 [5 yr]; replacements: reduced from 11.5 ± 4.3 [baseline] to 9.2 ± 3.1 [5 yr]; both p < 0.05). Complete continence rates after 5 yr were 44% (25/57) in de novo and 33% (5/15) in replacement UI patients, and 68% (39/57) and 67% (10/15) of UI patients were categorized as therapy responders by showing a >50% improvement in leaks. Disease severity (Urinary Symptom Profile domain 2), Numeric Rating Scale-based symptom bother, and disease-specific QoL (Ditrovie) improved significantly in both groups at all visits (p < 0.001). Adverse events related to device or procedure occurred in 51% (140/274) of patients, with 66% (152/229) of the events being classified as minor (Clavien-Dindo grade I and II). Surgical revisions were reported in 39% (89/229), which include permanent explants in 15% (34/229) of patients.

CONCLUSIONS

SOUNDS demonstrates the sustained effectiveness and QoL improvements of SNM in OAB patients after 5 yr in real-world conditions while maintaining an acceptable safety profile consistent with literature.

PATIENT SUMMARY

This study confirmed that French overactive bladder patients had a sustained symptom and bother reduction, and improvements in quality of life up to 5 yr after sacral neuromodulation device implantation.

Femtosecond laser hierarchical surface restructuring for next generation neural interfacing electrodes and microelectrode arrays

Long-term implantable neural interfacing devices are able to diagnose, monitor, and treat many cardiac, neurological, retinal and hearing disorders through nerve stimulation, as well as sensing and recording electrical signals to and from neural tissue. To improve specificity, functionality, and performance of these devices, the electrodes and microelectrode arrays-that are the basis of most emerging devices-must be further miniaturized and must possess exceptional electrochemical performance and charge exchange characteristics with neural tissue. In this report, we show for the first time that the electrochemical performance of femtosecond-laser hierarchically-restructured electrodes can be tuned to yield unprecedented performance values that significantly exceed those reported in the literature, e.g. charge storage capacity and specific capacitance were shown to have improved by two orders of magnitude and over 700-fold, respectively, compared to un-restructured electrodes. Additionally, correlation amongst laser parameters, electrochemical performance and surface parameters of the electrodes was established, and while performance metrics exhibit a relatively consistent increasing behavior with laser parameters, surface parameters tend to follow a less predictable trend negating a direct relationship between these surface parameters and performance. To answer the question of what drives such performance and tunability, and whether the widely adopted reasoning of increased surface area and roughening of the electrodes are the key contributors to the observed increase in performance, cross-sectional analysis of the electrodes using focused ion beam shows, for the first time, the existence of subsurface features that may have contributed to the observed electrochemical performance enhancements. This report is the first time that such performance enhancement and tunability are reported for femtosecond-laser hierarchically-restructured electrodes for neural interfacing applications.

[Urinary incontinence: a good diagnosis as a basis for treatment]

Urinary incontinence: a good diagnosis as a basis for treatment Abstract. Abtract: Everyone has experienced incontinence at an early age. However, it also affects approximately 200 million people worldwide at the adult age. This common condition is frequently underreported by patients but can dramatically limit their social life. Subject to appropriate differential diagnosis, urinary incontinence is a condition that can be treated with good results in the majority of patients. This article provides a review of the essential symptomatology and current treatments, so that clinicians confronted with the problem may adopt the appropriate management.

Pooled analysis of the efficacy and safety of tibial nerve stimulation versus antimuscarinic agents in the management of overactive bladder syndrome

OBJECTIVES

The purpose of this meta-analysis was to evaluate the efficacy and safety of tibial nerve stimulation (TNS) versus antimuscarinic agents in the management of overactive bladder (OAB) syndrome.

METHODS

The databases MEDLINE, EMBASE, the Cochrane Controlled Trial Register of Controlled Trials from 2000 to May 2021 were searched to identify randomized controlled trials that referred to the use of TNS and antimuscarinic agents for the treatment of OAB syndrome. A systematic review and meta-analysis was conducted.

RESULTS

Eight publications involving 420 patients were included in the meta-analysis. In the analysis, we found TNS had a comparable effect with antimuscarinic agents on micturition per day, nocturia, urge incontinence, and voided volume (P = .9; .4; .78; .44, respectively). Scores measured by questionnaires Overactive Bladder Symptom Score and Overactive Bladder questionnaire Short Form items also indicated no statistical difference between 2 groups. TNS group had a significantly less discontinuation rate and adverse events (P = .003; .0001).

CONCLUSIONS

TNS is as effective as antimuscarinic agents for the treatment of OAB. Moreover, TNS appears to be more tolerable and safer than antimuscarinic agents.

Female Urgency, Trial of Urodynamics as Routine Evaluation (FUTURE study): a superiority randomised clinical trial to evaluate the effectiveness and cost-effectiveness of invasive urodynamic investigations in management of women with refractory overactive bladder symptoms

BACKGROUND

Overactive bladder (OAB) syndrome is a symptom complex affecting 12-14% of the UK adult female population. Symptoms include urinary urgency, with or without urgency incontinence, increased daytime urinary frequency and nocturia. OAB has a negative impact on women's social, physical, and psychological wellbeing. Initial treatment includes lifestyle modifications, bladder retraining, pelvic floor exercises and pharmacological therapy. However, these measures are unsuccessful in 25-40% of women (refractory OAB). Before considering invasive treatments, such as Botulinum toxin injection or sacral neuromodulation, most guidelines recommend urodynamics to confirm diagnosis of detrusor overactivity (DO). However, urodynamics may fail to show evidence of DO in up to 45% of cases, hence the need to evaluate its effectiveness and cost-effectiveness. FUTURE (Female Urgency, Trial of Urodynamics as Routine Evaluation) aims to test the hypothesis that, in women with refractory OAB, urodynamics and comprehensive clinical assessment is associated with superior patient-reported outcomes following treatment and is more cost-effective, compared to comprehensive clinical assessment only.

METHODS

FUTURE is a pragmatic, multi-centre, superiority randomised controlled trial. Women aged ≥ 18 years with refractory OAB or urgency predominant mixed urinary incontinence, and who have failed/not tolerated conservative and medical treatment, are considered for trial entry. We aim to recruit 1096 women from approximately 60 secondary/tertiary care hospitals across the UK. All consenting women will complete questionnaires at baseline, 3 months, 6 months and 15 months post-randomisation. The primary outcome is participant-reported success at 15 months post-randomisation measured using the Patient Global Impression of Improvement. The primary economic outcome is incremental cost per quality-adjusted life year gained at 15 months. The secondary outcomes include adverse events, impact on other urinary symptoms and health-related quality of life. Qualitative interviews with participants and clinicians and a health economic evaluation will also be conducted. The statistical analysis of the primary outcome will be by intention-to-treat. Results will be presented as estimates and 95% CIs.

DISCUSSION

The FUTURE study will inform patients, clinicians and policy makers whether routine urodynamics improves treatment outcomes in women with refractory OAB and whether it is cost-effective.

TRIAL REGISTRATION

ISRCTN63268739 . Registered on 14 September 2017.

Statewide Success of Staged Sacral Neuromodulation for the Treatment of Urinary Complaints in California (2005-2011)

PURPOSE

Sacral neuromodulation (SNS) is approved by the Food and Drug Administration as a third-line treatment for refractory overactive bladder, idiopathic urinary retention, and fecal incontinence. Prior to implantation of an implantable pulse generator, all patients undergo a trial phase to ensure symptom improvement. The published success rates of progression from the test phase to permanent implant vary widely (range, 24% to >90%). We sought to characterize success rates using a statewide registry.

METHODS

Using nonpublic data, we identified SNS procedures using the California Office of Statewide Planning and Development ambulatory surgery database from 2005 to 2011. A successful trial was defined as receiving a stage 2 generator implantation after trial lead placement. Multivariable logistic regression was performed to identify factors associated with staged success.

RESULTS

During the study period, 1396 patients underwent a staged SNS procedure, with 962 (69%) subsequently undergoing generator placement. Successful trial rates were 72% for overactive bladder wet, 69% for urgency/frequency, 68% for interstitial cystitis, 67% for neurogenic bladder, and 57% for urinary retention. On multivariate logistic regression, only male sex (odds ratio, 0.51) and urinary retention [odds ratio, 0.54) were significantly associated with lower odds of success, whereas age, race/ethnicity, medical insurance, and placement at an academic or high-volume institution had no association.

CONCLUSIONS

The "real world" success rates for staged SNS implantation in California are less than those observed by some academic centers of excellence but better than previously reported for Medicare beneficiaries. Successful trial rates for interstitial cystitis and neurogenic voiding dysfunction are similar to refractory overactive bladder.

Axonics® system for treatment of overactive bladder syndrome and urinary urgency incontinence

Introduction: Overactive bladder and urge urinary incontinence affect millions of women and men and results in billions of dollars in health-care expenses. First- and second-line therapy includes behavioral modifications and/or pharmacotherapies however, many patients' symptoms remain or progress on these treatments. There has been concern regarding the detrimental side effects of the most widely prescribed medications for these bladder symptom management.Areas covered: As a result, there has been increased interest in continuous sacral neuromodulation, an FDA approved therapy for refractory urinary urgency and urge urinary incontinence. In this article, we specifically review current research on the efficacy and patient/provider satisfaction and safety profile of the Axonics® System. In addition, we address the current state of sacral neuromodulation and potential future direction and applicability.Expert opinion: The Axonics® system is a safe effective device for the treatment of overactive bladder and urinary urge incontinence. Additionally, it affords patient's the convenience of a rechargeable, compact, MRI safe system. It should be noted that the rechargeable system, while allowing for approximately 15 years of battery and lead life, may have its challenges in terms of charge burden. Furthermore, this system is easily adapted for experienced implanters of sacral neuromodulating devices.

Sharpened and Mechanically Durable Carbon Fiber Electrode Arrays for Neural Recording

Bioelectric medicine treatments target disorders of the nervous system unresponsive to pharmacological methods. While current stimulation paradigms effectively treat many disorders, the underlying mechanisms are relatively unknown, and current neuroscience recording electrodes are often limited in their specificity to gross averages across many neurons or axons. Here, we develop a novel, durable carbon fiber electrode array adaptable to many neural structures for precise neural recording. Carbon fibers ( [Formula: see text] diameter) were sharpened using a reproducible blowtorchmethod that uses the reflection of fibers against the surface of a water bath. The arrays were developed by partially embedding carbon fibers in medical-grade silicone to improve durability. We recorded acute spontaneous electrophysiology from the rat cervical vagus nerve (CVN), feline dorsal root ganglia (DRG), and rat brain. Blowtorching resulted in fibers of 72.3 ± 33.5-degree tip angle with [Formula: see text] exposed carbon. Observable neural clusters were recorded using sharpened carbon fiber electrodes fromrat CVN ( [Formula: see text]), feline DRG ( [Formula: see text]), and rat brain ( [Formula: see text]). Recordings from the feline DRG included physiologically relevant signals from increased bladder pressure and cutaneous brushing. These results suggest that this carbon fiber array is a uniquely durable and adaptable neural recordingdevice. In the future, this device may be useful as a bioelectric medicine tool for diagnosis and closed-loop neural control of therapeutic treatments and monitoring systems.

Is a 50% improvement threshold adequate to justify progression from sacral neuromodulation testing to implant?

PURPOSE

A ≥50% subjective improvement in urinary symptoms during sacral neuromodulation testing (SNM-I) is currently used as the indication for progression to second-stage implantation (SNM-II). While most patients will have successful SNM-I and proceed to SNM-II, deterioration in efficacy over time has been reported. It remains unclear if the durability of efficacy is related to the initial symptom reduction. We sought to determine if the degree of improvement after SNM-I is sufficient to predict long-term success.

METHODS

The records of all patients who underwent sacral neuromodulation (SNM) for overactive bladder were reviewed. Subjects were divided into those who reported 50%-75% improvement (Group 1) and more than 75% improvement (Group 2) after SNM-I. Differences in clinical variables and long-term device efficacy were compared between groups.

RESULTS

Of 213 patients who underwent SNM-I, 137 underwent permanent device implantation. A total of 76 (55%) and 61 (45%) patients reported 50%-75% (Group 1) and more than 75% (Group 2) symptomatic improvement, respectively. With a mean follow-up of 46 months, 44% of Group 1 patients and 68% of Group 2 patients still had a functioning device providing the symptomatic benefit (p = 0.007). Univariate analyses identified the presence of stress urinary incontinence at baseline and having a more than 75% improvement after SNM-I as predictors of long-term functional success.

CONCLUSIONS

Compared to patients reporting 50%-75% symptomatic reduction after SNM-I, individuals with a more than 75% improvement during SNM-I were more likely to maintain device efficacy over time. Additional study is warranted to determine if the improvement threshold for progression to SNM-II should be increased.

[Functional results and satisfaction in 44 patients after implantation of a NS3-type sacral neurostimulator for refractory idiopathic overactive bladder followed at 43 months, single-center series]

OBJECTIVES

Sacred neuromodulation (SNM) has been used in France since 1997 for the management of non-neurogenic urinary disorders that do not respond to first-line pharmacological treatment. The aim of this study is to analyze the clinical efficacy and satisfaction of patients with refractory idiopathic overactive bladder (OAB) treated with SNM.

METHODS

This single-center retrospective series included 59 patients with refractory OAB of idiopathic origin and eligible for the SNM between January 2010 and December 2017. Demographic data, history of pelvic surgery, complications according to Clavien-Dindo classification, as well as revision and explantation rates were collected. All the patients included underwent a test phase. Therapeutic success for the test phase and definitive implantation was defined by≥50% improvement. Satisfaction was a secondary criteria.

RESULTS

Of the 59 patients tested for SNM, 44 patients had a permanent implantation, of which 36 (82%) were women and 8 (12%) were men. The median age of the study was 55 years old. The median follow-up was 43 months [21,2-66,5]. All of the patients had an idiopathic refractory OAB. The median time between test and final implantation was 28 days [18-35]. The success rate for all patients tested was 60% (34/59). In patients implanted, 34 patients (77%) had clinical improvement. Adverse events had to be managed including multiple re-parameterizations (n=13), device revision (n=16), or even device implantation (n=8). The satisfaction rate was 82% (36/44).

CONCLUSION

With a median follow-up of 43 months, this retrospective study on NMS shows the efficacy of second-line SNM for idiopathic OAB. This technique remains minimally invasive but with significant adverse events when informing our patients.

LEVEL OF EVIDENCE

3.

Systematic Literature Review and Meta-Analysis of Sacral Neuromodulation (SNM) in Patients with Neurogenic Lower Urinary Tract Dysfunction (nLUTD): Over 20 Years' Experience and Future Directions

INTRODUCTION

Sacral neuromodulation (SNM) has been used in carefully selected patients with neurogenic lower urinary tract dysfunctions (nLUTD) for over two decades.

METHODS

The aim of the current work was to perform a systematic literature review and meta-analysis of studies reporting the safety and effectiveness of SNM in patients with nLUTD (neurogenic detrusor overactivity, non-obstructive urinary retention, or a combination of both). For this purpose a systematic literature research was conducted using Embase (OvidSP), MEDLINE (OvidSP), MEDLINE In-Process Citations & Daily Update (OvidSP), MEDLINE (OvidSP) e-Pub ahead of print, Cochrane Central Register of Controlled Trials (CENTRAL), NIH Clinicaltrials.gov, and WHO International Clinical Trials Registry Platform (ICTRP) between 1998 and March 2020, supplemented by a hand search.

RESULTS

Forty-seven studies were included in the systematic literature review. Twenty-one studies comprising a total of 887 patients were included in the meta-analysis of test SNM. The pooled success rate of SNM test stimulation was 66.2% (95% CI 56.9-74.4). Depending on neurogenic conditions test success rates varied greatly. Twenty-four studies with a total of 428 patients were included in the meta-analysis of permanent SNM. The success rate of pooled permanent SNM was 84.2% (95% CI 77.8-89.0). Among the identified studies, the most common adverse events (AEs) were loss of effectiveness, infection, pain at implant site, and lead migration with AE rates of 4.7%, 3.6%, 3.2%, and 3.2%, respectively. Limitations entail lower level of evidence (Oxford classification 3-4) of included studies, significant risk of bias, small sample sizes in some studies, the inclusion of retrospective case series, substantial between-study heterogeneity, heterogeneous patient populations, insufficient disease classification, and variations in terms of outcome parameters as well as techniques. Furthermore, long-term data are limited.

CONCLUSION

This meta-analysis supports not only the benefits of permanent SNM for various nLUTDs but also high overall success rates, similar to idiopathic patients. Current data of the analyzed studies showed that SNM is safe for these patients. However, more vigorous studies and/or registries are needed before definitive conclusions can be drawn.

[Follow-up and evaluation of non-neurogenic OAB treatments]

INTRODUCTION

The purpose of monitoring a patient treated for overactive bladder (OAB) is to ensure the effectiveness of the treatment and to detect any side effects.

OBJECTIVE

To synthesize current knowledge on the follow-up and the evaluation of non-neurogenic OAB treatments.

METHOD

A systematic literature review based on Pubmed, Embase, Google Scholar was conducted in June 2020.

RESULTS

The definition of success of OAB treatments is not consensual. Definitions of success in clinical trials usually use bladder diary data. However, they cannot always be transposed into clinical practice because they do not measure the overall effectiveness of a treatment, reported by the patient, or the satisfaction with the treatment. It is then necessary to have symptom questionnaires with an assessment of quality of life. Indeed, the concept of therapeutic success is different depending on the view of the physician or the patient. It is therefore important to carefully assess with the patient, and before initiating any treatment, the objectives and expected results of the treatment. The definition of "refractory" OAB is heterogeneous but important to select candidates for second-line treatments. Monitoring a patient with OAB is essential to adapt the treatment to efficacy and tolerance, but also to detect any change in symptoms that may reveal another urological disease.

CONCLUSION

The success or failure of OAB treatments depends on the interaction of many factors, including objective criteria measured by the clinician, and subjective criteria of perception of the treatment effectiveness by the patient.

Sacral Nerve Stimulation in Parkinson's Disease Patients With Overactive Bladder Symptoms

OBJECTIVE

To assess the efficacy, safety, and outcomes of sacral nerve stimulation (SNS) for Parkinson's disease (PD) patients with overactive bladder symptoms.

METHODS

We retrospectively reviewed PD patients who underwent Stage I SNS. Demographics, urodynamic data, and baseline voiding function were analyzed. Efficacy and safety of treatment were determined by rate of progression to Stage II, explantation, and surgical revision. Long-term outcomes were assessed using voiding diaries and/or clinic notes.

RESULTS

Sixty percent (9/15) experienced ≥50% improvement in urinary parameters and proceeded to Stage II. There was no significant difference in age, body mass index, comorbidities, PD disease duration, or levodopa equivalent daily dose between successful and nonsuccessful Stage I patients. However, 100% of female patients experienced Stage I success compared to 44% of male PD patients (P = .04). Individuals with >12-month follow-up experienced an average reduction of 6 voids/day. No patients required revision or explantation of their device at latest clinic follow-up (22.2 ± 7.8 months). Higher maximal urethral closure pressures, detrusor pressure at maximum flow rate (PdetQmax), post-void residual volume, and mean bladder outlet obstruction index were observed in the Stage I trial failures.

CONCLUSION

At our institution, PD patients have a similar rate of progression to Stage II compared to the general population. SNS is an effective therapy that should be considered among the treatment options for PD patients with overactive bladder symptoms. Urodynamic parameters associated with obstruction may be predictive of SNS failure in PD patients and may help guide patient selection, however further studies are needed.

An Efficient Noninvasive Neuromodulation Modality for Overactive Bladder Using Time Interfering Current Method

OBJECTIVE

The present study aimed to evaluate a new tibial nerve stimulation (TNS) modality, which uses interferential currents, in terms of the stimulation electric field penetration efficiency into the body and physiological effectiveness.

METHODS

In silico experiments were performed to analyze the penetration efficiency of proposed interferential current therapy (ICT). Based on this, we performed in vivo experiments to measure excitation threshold of ICT for the tibial nerve, which is related to stimulation field near the nerve. Regarding analysis of the physiological effectiveness, in vivo ICT-TNS was performed, and changes in bladder contraction frequency and voiding volume were measured. The penetration efficiency and physiological effectiveness of ICT were evaluated by comparison with those of conventional TNS using transcutaneous electrical nerve stimulation (TENS).

RESULTS

Simulation results showed that ICT has high penetration efficiency, thereby generating stronger field than TENS. These results are consistent with the in vivo results that nerve excitation threshold of ICT is lower than that of TENS. Moreover, ICT-TNS decreased contraction frequency and increased voiding volume, and its performance was profound compared with that of TENS-TNS.

CONCLUSION

The proposed ICT is more efficient in inducing the stimulation field near the tibial nerve placed deep inside the body compared with conventional TENS and shows a good clinical effectiveness for TNS.

SIGNIFICANCE

The high efficiency of ICT increases the safety of noninvasive neurostimulation; therefore, it has clinical potential to become a promising modality for TNS to treat OAB and other peripheral neurostimulations.

Comparing the Efficacy of OnabotulinumtoxinA, Sacral Neuromodulation, and Peripheral Tibial Nerve Stimulation as Third Line Treatment for the Management of Overactive Bladder Symptoms in Adults: Systematic Review and Network Meta-Analysis

The American Urological Association guidelines for the management of non-neurogenic overactive bladder (OAB) recommend the use of OnabotulinumtoxinA, sacral neuromodulation (SNM), and peripheral tibial nerve stimulation (PTNS) as third line treatment options with no treatment hierarchy. The current study used network meta-analysis to compare the efficacy of these three modalities for managing adult OAB syndrome. We performed systematic literature searches of several databases from January 1995 to September 2019 with language restricted to English. All randomized control trials that compared any dose of OnabotulinumtoxinA, SNM, and PTNS with each other or a placebo for the management of adult OAB were included in the study. Overall, 17 randomized control trials, with a follow up of 3–6 months in the predominance of trials (range 1.5–24 months), were included for analysis. For each trial outcome, the results were reported as an average number of episodes of the outcome at baseline. Compared with the placebo, all three treatments were more efficacious for the selected outcome parameters. OnabotulinumtoxinA resulted in a higher number of complications, including urinary tract infection and urine retention. Compared with OnabotulinumtoxinA and PTNS, SNM resulted in the greatest reduction in urinary incontinence episodes and voiding frequency. However, comparison of their long-term efficacy was lacking. Further studies on the long-term effectiveness of the three treatment options, with standardized questionnaires and parameters are warranted.

Effects of Extracorporeal Magnetic Stimulation in Fecal Incontinence

Background

Fecal incontinence (FI) is a common condition that has devastating consequences for patients’ QOL. In some patients, the conventional functional pelvic floor electrical stimulation has been effective but is an invasive and embarrassing treatment. The object of the study was to evaluate the feasibility of functional extracorporeal magnetic stimulation (FMS) in strengthening the pelvic floor muscles without an anal plug and the embarrassment of undressing.

Materials and Methods

Thirty patients (26 female and 4 males) with FI were enrolled. All patients were assessed during a specialized coloproctology evaluation followed by endoanal ultrasonography and anorectal manometry. All patients underwent an FMS treatment once weekly for 8 weeks. Patients’ outcome was assessed by the Cleveland Clinic Fecal Incontinence Score (CCFIS) and by the fecal incontinence QOL questionnaire (FIQL).

Results

After 8 weeks, the number of solid and liquid stool leakage per week was significantly reduced (p<0.05) with a significant improvement of the CCFIS and of the FIQL (p<0.05). Moreover, the authors recorded a missed recruitment of the agonist and antagonists’ defecation muscles.

Conclusion

FMS is a safe, non-invasive and painless treatment for FI. It could be recommended for selected patients with non-surgical FI to ensure a rapid clinical improvement.

[The use of surgical neuromodulation to treat chronic pelvic pain]

Chronic pelvic pain (CPP) is a pain syndrome that is very difficult to treat. The effectiveness of CPP treatment remains low despite the use of integrated approaches. That is why it is necessary to search for new treatment approaches and methods. Surgical neuromodulation has recently been used increasingly often to treat CPP.

OBJECTIVE

To evaluate the effectiveness of different types of neurostimulation in patients with chronic pelvic pain.

MATERIAL AND METHODS

Thirty-two patients were treated at the N.N. Burdenko National Scientific and Practical Center for Neurosurgery. All the patients were diagnosed with CPP and transferred to the Center because of unsatisfactory results of earlier treatment. The mean duration of pain was 8.6 years (range: 1-31 years). Pain intensity and the neuropathic component of the pain syndrome were assessed using the conventional scales and questionnaires (VAS, LANSS, Pain Detect, and DN4). The levels of anxiety, depression, and catastrophic pain were also assessed. The effect of pain on quality of life was evaluated using the modified Brief Pain Inventory (BPI). All the selected patients underwent trial lead implantation at the first stage. Sacral root stimulation was used in 15 patients (unilateral one in 8 patients and bilateral one in 7 patients); three patients underwent spinal cord stimulation; 14 patients were treated with combined neurostimulation.

RESULTS

In 27 (84.37%) patients, the trial period was regarded as positive and the systems were implanted for chronic neurostimulation. After one year of stimulation, the mean VAS score for pain intensity was 3.53 (compared to 8.61 before the surgery). Regarding quality of life, the most significant effects of treatment were as follows: the number of pain paroxysms was reduced; physical self-maintenance, social life, sleep, and sexual activity were improved; and daily physical activity was increased.

CONCLUSION

. Neurostimulation ensures a stable pain relief and improves quality of life in patients with chronic pelvic pain refractory to conservative treatment.

Neuromodulation in urology, state of the art

Sacral neuromodulation is an approved and validated treatment for overactive bladder syndrome, chronic non-obstructive retention, and chronic pelvic pain. Percutaneous tibial nerve stimulation is a less invasive approach of neuromodulation. We performed a literature research to assess the current evidence available about neuromodulation. Both techniques appear to be effective and safe third-line treatments. The overall success rate ranges from 43% to 85% for sacral neuromodulation and from 40% to 79.5% for percutaneous tibial nerve stimulation. Sacral neuromodulation has a higher incidence of complications in comparison to percutaneous tibial nerve stimulation, due to the more invasive surgical technique and the presence of a permanent implant. The incidence of surgical revision ranges between 9% and 33%. The most frequent complication with sacral neuromodulation is pain at implant site (15%-42%), followed by lead migration (4%-21%), pain at lead site (5.4%-19.1%), leg pain (18%), and infection (5.7%-6.1%). The quality of the studies on sacral neuromodulation and percutaneous tibial nerve stimulation in literature is quite modest, because of the shortage of good randomized clinical trial; most of the studies are prospective observational studies with mid-term follow-up.

INFRA-OBTURATOR TENSION SLING FOR URINARY INCONTINENCE TREATMENT

Stress incontinence occurs due to the inability to control an urge to urinate, which affects the quality of daily life. Although there is an existing therapeutics with polymer mesh tape, it is hard to fix around the urethra to restore the function of the pubourethral ligament. Therefore, in this research, an infra-obturator tension (IOT) sling was introduced to minimize the mobility of the bladder and urethra against intra-abdominal pressure. To verify the IOT performance, two different hypotheses were formulated: The hardness and volume of the IOT support the urethra and help prevent it from deforming by intra-abdominal pressure. The rotatory motion of the IOT can bend the urethra at the contact point and help restore the function of pubourethral ligament to increase vaginal tension. For the first hypothesis, a finite element simulation was conducted using three-dimensional geometrical model obtained by the computed tomography images of patients. For the second hypothesis, surgeons performed an IOT insertion operation and analyzed the sling rotation from the patients’ CT images (mean: 21∘). From the results, the mobility of the urethra was decreased because of IOT insertion. The mobility was also decreased because of the subsequent fibrotic changes from the encapsulation of the IOT.

Sacral neuromodulation for female pelvic floor disorders

Objective: To systematically review available studies on the effectiveness and safety of sacral neuromodulation (SNM) in women with various pelvic floor disorders not responding to more conservative treatment, as SNM is indicated in such women.

Methods: Data source: We did a systematic review through the PubMed and the Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement from 1998 to 2018 in English using the keywords ‘Sacral Neuromodulation’ and ‘Sacral Nerve Stimulation’.

Study selection: Randomised controlled trials and prospective studies were selected, with a minimum sample size of 20 patients and ≥6 months of follow-up.

Results: We identified 19 articles. A ≥50% reduction in symptoms qualifies the patient for a permanent implant. Several advances have been introduced into SNM to decrease the invasiveness of the procedure, including a smaller implantable pulse generator battery (improved comfort) and better localisation of the lead wire (improved outcome). The literature reports success for overactive bladder (OAB) to range between 56% and 68% (up to 80%). We report a 5-year therapeutic success rate of 67%. In our previous studies, 38% of our patients with urge urinary incontinence achieved complete continence at 60-months follow-up, with a therapeutic response rate of 57%. Effectiveness in patients with urinary retention and faecal incontinence are about 70% and 85%, respectively. Effectiveness in interstitial cystitis/bladder pain syndrome appears to be lower compared with OAB.

Conclusion: SNM is a safe and effective therapy for women with various pelvic floor disorders.

Abbreviations: BONT: botulinum toxin; FDA: USA Food and Drug Administration; FS: Fowler’s syndrome; FI: faecal incontinence; IC/BPS: interstitial cystitis/bladder pain syndrome; ICIQ-OABqol: International Consultation on Incontinence Modular Questionnaire-Overactive Bladder Symptoms Quality of Life; INS: implantable neurostimulator; OAB: overactive bladder; PET: positron emission tomography; PNE: peripheral nerve evaluation; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PTNM: posterior tibial nerve modulation; PVR: post-void residual urine; QoL: quality of life; RCT: randomised controlled trial; SNM: sacral neuromodulation; (U)UI: (urgency) urinary incontinence

What uro-gynecologists should know about sacral neuromodulation (SNM) for the treatment of refractory overactive bladder

PURPOSE

To inform uro-gynecologists about the current standards and latest developments of sacral neuromodulation (SNM) in women with overactive bladder (OAB).

METHODS

Literature search in the PubMed database for articles published between 1988 and 2019 on SNM for OAB in women.

RESULTS

In total, 361 articles were identified and 51 articles retrieved for the review. SNM shows an objective success rate of 70-80%, OAB cure rate of 17-47% and a subjective satisfaction rate of 80-90%. These benefits have to be weighed against an adverse event rate of approx. 40%. SNM is significantly more successful than switching to another antimuscarinic after failed antimuscarinic drug therapy. Efficacy of SNM is slightly lower compared to bladder wall injections with 200 U botulinum toxin in the first months but efficacy of both treatments appears to be similar after 24 months. MRI examinations of patients with a sacral neurostimulator should only be performed after radiologist consultation. Sacral neurostimulators in patients with another pacemaker system should only be implanted after interdisciplinary consultation. The sacral neuromodulator should be turned off during pregnancy and delivery. SNM for OAB in patients with concomitant female sexual dysfunction or fecal incontinence seems to be beneficial.

CONCLUSIONS

SNM is a successful and recommended second-line treatment of OAB. Sacral neurostimulators should preferably be implanted in SNM-centers because complications and the frequency of revisions are significantly reduced with increasing experience of the surgeon.

What Is New in Neuromodulation for Overactive Bladder?

We reviewed the available studies on efficacy and safety of percutaneous tibial nerve stimulation (PTNS) and sacral nerve modulation (SNM) for overactive bladder (OAB) symptoms not responsive to conservative treatments. We limited our search to randomized trials, in English, with at least 20 adult patients, and 6 mo and 12 wk of follow-up for SNM and PTNS, respectively, published between January 1998 and December 2017. Therapeutic success ranges from 61% to 90% for SNM and from 54% to 79% for PTNS. Both techniques are effective and safe, with no life-threatening adverse effects. PTNS is a less invasive technique that gives good results in short time with fewer side effects.

PATIENT SUMMARY

Sacral nerve modulation and percutaneous tibial nerve stimulation are effective and safe in patients with overactive bladder syndrome not responsive to standard medical therapy.

Development of a Remote-Controlled Implantable Rat Sacral Nerve Stimulation System

OBJECTIVES

Sacral nerve stimulation (SNS) is a surgical treatment of urinary and fecal incontinence. Despite its clinical efficacy, the mechanisms of action of SNS are still poorly known. This may be related to the use of acute stimulation models. Up to date, no rodent model of chronic SNS implants has been developed. Therefore, the aim of this study was to create a fully implantable and remotely controllable stimulating device to establish an animal model of chronic SNS.

MATERIALS AND METHODS

The stimulating device consisted of an implantable pulse generator linked to a platinum electrode. The communication with the device was made through an inductive link which allowed to adjust the stimulation parameters; that is, to turn the device on and off or check the battery status remotely. Rats underwent two surgical procedures. In the first procedure, we achieved chronic sacral stimulation but the implanted electrode was not fixated. In the second procedure, the electrode was fixated in the sacral foramen using dental resin. In both cases, the correct positioning of the electrode was evaluated by computed tomography (CT) imaging and the presence of tail tremor in response to high intensity stimulation. We only tested the function of implanted electrode with fixation using micturition frequency assessment following bipolar or unipolar SNS for three days after recovery.

RESULTS

CT imaging showed that implantation of the electrode required fixation as we found that the second surgical procedure yielded a more precise placement of the implanted electrode. The correct placement of implanted electrode observed with imaging was always correlated with a successful tail tremor response in rats, therefore we pursued our next experiments with the second surgical procedure and only assessed the tail tremor response. We found that both bipolar and unipolar SNS reduced micturition frequency.

CONCLUSION

This stimulating device provides an efficient method to perform chronic SNS studies in rats.

International Continence Society best practice statement for use of sacral neuromodulation

AIMS

Sacral neuromodulation (SNM) is an accepted therapy for a variety of conditions. However, despite over 20 years of experience, it remains a specialized procedure with a number of subtleties. Here we present the recommendations issued from the International Continence Society (ICS) SNM Consensus Panel.

METHODS

Under the auspices of the ICS, eight urologists, three colorectal surgeons and two urogynecologists, covering a wide breadth of geographic and specialty interest representation, met in January 2017 to discuss best practices for neuromodulation. Suggestions for statements were submitted in advance and specific topics were assigned to committee members, who prepared and presented supporting data to the group, at which time each topic was discussed in depth. Best practice statements were formulated based on available data. This document was then circulated to multiple external reviewers after which final edits were made and approved by the group.

RESULTS

The present recommendations, based on the most relevant data available in the literature, as well as expert opinion, address a variety of specific and at times problematic issues associated with SNM. These include the use of SNM for a variety of underlying conditions, need for pre-procedural testing, use of staged versus single-stage procedures, screening for success during the trial phase, ideal anesthesia, device implantation, post-procedural management, trouble-shooting loss of device function, and future directions for research.

CONCLUSIONS

These guidelines undoubtedly constitute a reference document, which will help urologists, gynecologists, and colorectal surgeons optimize their use of SNM for refractory urinary urgency and frequency, UUI, NOR, and FI.

Baseline symptom severity and therapeutic success in a large prospective trial of sacral neuromodulation therapy for overactive bladder patients

INTRODUCTION

The InSite trial is a prospective, multicenter post-approval study of subjects receiving sacral neuromodulation (SNM) therapy with the InterStim^® System. Enrolled subjects had bothersome symptoms of overactive bladder (OAB). The purpose of this analysis was to determine if severity of baseline symptoms had an impact on clinical outcomes.

METHODS

For device implant, therapeutic success was defined as a  ≥50% improvement in average leaks/day, or in voids/day or a return to normal voiding frequency. Groups were dichotomized into less versus more severe based on median number of leaks and voids. Subjects were grouped as less severe <2 leaks/day for UI; <11 voids/day for UF and more severe ≥2 leaks/day for UI;  ≥11 voids/day for UF. Therapeutic success at 12 and 24 months were compared between groups.

RESULTS

Three hundred and forty subjects completed test stimulation and 272 (80%) subjects received a full system implant. On average UI subjects had 1.3 leaks/day in the less severe group and 4.5 leaks/day in the more severe group. UI success rates were not statistically different between severity groups at 12 months or 24 months). At baseline, on average UF subjects had 9.4 voids/day for the less severe group and 15.1 voids/day for the more severe group. UF success rates were not statistically different between severity groups at 12 months or 24 months.

CONCLUSION

Data evaluating efficacy based on symptom severity demonstrates that SNM is effective in treating both less severe and more severely affected groups for both UI and UF at 12 and 24 months.

Specific Changes in Brain Activity during Urgency in Women with Overactive Bladder after Successful Sacral Neuromodulation: A Functional Magnetic Resonance Imaging Study

PURPOSE

The mechanism of sacral neuromodulation is poorly understood. We compared brain activity during urgency before and after sacral neuromodulation in women with overactive bladder and according to the response to treatment.

MATERIALS AND METHODS

Women with refractory overactive bladder who elected sacral neuromodulation were invited to undergo functional magnetic resonance imaging before and after treatment. During imaging the bladder was filled until urgency was experienced. Regions of interest were identified a priori and brain activity in these regions of interest was compared before and after treatment as well as according to the treatment response. Whole brain exploratory analysis with an uncorrected voxel level threshold of p <0.001 was also performed to identify additional brain regions which changed after sacral neuromodulation.

RESULTS

Of the 12 women who underwent a pretreatment functional magnetic resonance imaging examination 7 were successfully treated with sacral neuromodulation and underwent a posttreatment examination. After sacral neuromodulation brain activity decreased in the left anterior cingulate cortex, the bilateral insula, the left dorsolateral prefrontal cortex and the bilateral orbitofrontal cortex (each p <0.05). No new brain regions showed increased activity after sacral neuromodulation. Pretreatment brain activity levels in the bilateral anterior cingulate cortex, the right insula, the bilateral dorsolateral prefrontal cortex, the right orbitofrontal cortex, the right supplementary motor area and the right sensorimotor cortex were higher in women who underwent successful treatment (each p <0.05).

CONCLUSIONS

Brain activity during urgency changes after successful sacral neuromodulation. Sacral neuromodulation may be more effective in women with higher levels of pretreatment brain activity during urgency.

Electrical neuromodulation in the management of lower urinary tract dysfunction: evidence, experience and future prospects

Lower urinary tract dysfunction (LUTD) is common and causes a spectrum of morbidity and decreased quality of life (QoL) for patients. LUTD can range from urinary retention to urge incontinence, and includes a variety of syndromes, with the most common and widely recognized being overactive bladder (OAB). The classic treatments of LUTD and OAB comprise different strategies including behavioral therapies, medications and minimally invasive or invasive surgical procedures. Generally, once patients have tried behavioral modifications and oral medical therapy, and have not experienced adequate relief of their symptoms, the next step is to consider minimally invasive therapies. In the last two decades since FDA approval, sacral nerve stimulation (SNS) has become an accepted intervention, with increasing use and evidence of effectiveness for LUTD, specifically OAB and non-obstructive urinary retention. SNS has shown both objective and subjective improvement in voiding symptoms in several randomized controlled trials (RCTs) when compared to sham or standard medical therapy. The main limitations for more extensive use include relatively high cost, implantation of a device and possibly reoperation secondary to adverse events (AE). Percutaneous tibial nerve stimulation (PTNS) is a less invasive, less direct and less expensive method for neuromodulation, which has also shown effectiveness in several randomized and non-randomized trials, including comparable improvement rates to anticholinergics in OAB management. However, the efficacy of PTNS is only maintained for a short period after the stimulation is delivered. This technique has a much lower rate of AE compared to SNS, but with the inconvenience of weekly visits for stimulation, although implantable devices are on the horizon. In this article we review the mechanism of action, indications, effectiveness and complications related to SNS and PTNS therapy for LUTD.

Efficacy and Safety of Sacral and Percutaneous Tibial Neuromodulation in Non-neurogenic Lower Urinary Tract Dysfunction and Chronic Pelvic Pain: A Systematic Review of the Literature

CONTEXT

Neuromodulation is considered in patients with non-neurogenic lower urinary tract dysfunction (LUTD) not responsive to conservative treatment.

OBJECTIVE

To systematically review the available studies on efficacy and safety of sacral neuromodulation (SNM) and percutaneous tibial nerve stimulation (PTNS) in non-neurogenic LUTDs not responsive to conservative treatments.

EVIDENCE ACQUISITION

A literature research was conducted in PubMed/Medline and Scopus, restricted to articles in English, published between January 1998 and June 2017, with at least 20 patients and 6 mo of follow-up.

EVIDENCE SYNTHESIS

Twenty-one reports were identified. Concerning SNM, the improvement of ≥50% in leakage episodes ranged widely between 29% and 76%. Overall dry rate ranged between 43% and 56%. Overall success/improvement rate in PTNS varied between 54% and 59%. Symptom improvement or efficacy in interstitial cystitis/bladder pain syndrome patients appeared to be lower compared with other indications in both techniques. Safety data showed fewer side effects in patients submitted to PTNS.

CONCLUSIONS

Neuromodulation gives good results and is a safe therapy for patients with overactive bladder or chronic nonobstructive urinary retention with long-lasting efficacy. Moreover, PTNS has been shown to have good success rates and fewer side effects compared with SNM. These data have to be confirmed with long-term follow-up.

PATIENT SUMMARY

Sacral neuromodulation can improve low urinary tract symptoms in selected patients; it appears to be a safe therapy for nonresponders to standard medical therapies. Percutaneous tibial nerve stimulation (PTNS) is a less invasive technique that gives good results in short time with fewer side effects. However, we must consider that PTNS has not been tested in the long term and results are lower if compared with SNM.

Role of sacral neuromodulation in modern urogynaecology practice: a review of recent literature

Sacral neuromodulation (SNM) offers promise in the therapy of many pelvic floor disorders. This innovative treatment has slowly gained popularity. A review of recent literature is presented in relation to its efficacy and complications in various pelvic floor conditions: overactive bladder and urge urinary incontinence, chronic urinary retention, painful bladder syndrome, pelvic pain and double incontinence. It is a minimally invasive, completely reversible safe procedure with good long-term outcomes. However, the treatment is costly, the revision rate is high and patients require life-long follow-up. SNM should always be considered in suitable patients before offering bladder augmentation procedures or urinary diversion or permanent catheterization for bladder dysfunction. SNM should also be considered in patients with double incontinence, after discussion in a urogynaecology/colorectal multidisciplinary team.