Prospective Randomized Crossover Trial Comparing Continuous and Cyclic Stimulation in InterStim Therapy

What Are the Short-term Benefits and Potential Harms of Therapeutic Modalities for the Management of Overactive Bladder Syndrome in Women? A Review of Evidence Under the Auspices of the European Association of Urology, Female Non-neurogenic Lower Urinary Tract Symptoms Guidelines Panel

CONTEXT

Overactive bladder syndrome (OAB) is highly prevalent among women and has a negative impact on their quality of life. The current available treatments for OAB symptoms include conservative, pharmacological, or surgical modalities.

OBJECTIVE

To provide an updated contemporary evidence document regarding OAB treatment options and determine the short-term effectiveness, safety, and potential harms of the available treatment modalities for women with OAB syndrome.

EVIDENCE ACQUISITION

The Medline, Embase, and Cochrane controlled trial databases and clinicaltrial.gov were searched for all relevant publications up to May 2022. The risk of bias assessment followed the recommended tool in the Cochrane Handbook for Systematic Reviews of Interventions, and quality of evidence was assessed using the modified Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. A meta-analysis was performed where appropriate.

EVIDENCE SYNTHESIS

Antimuscarinics and beta-3 agonists were significantly more effective than placebo across most outcomes, with beta-3 agonists being more effective at reducing nocturia episodes and antimuscarinics causing significantly higher adverse events. Onabotulinumtoxin-A (Onabot-A) was more effective than placebo across most outcomes, but with significantly higher rates of acute urinary retention/clean intermittent self-catheterisation (six to eight times) and urinary tract infections (UTIs; two to three times). Onabot-A was also significantly better than antimuscarinics in the cure of urgency urinary incontinence (UUI) but not in the reduction of mean UUI episodes. Success rates of sacral nerve stimulation (SNS) were significantly higher than those of antimuscarinics (61% vs 42%, p = 0.02), with similar rates of adverse events. SNS and Onabot-A were not significantly different in efficacy outcomes. Satisfaction rates were higher with Onabot-A, but with a higher rate of recurrent UTIs (24% vs 10%). SNS was associated with 9% removal rate and 3% revision rate.

CONCLUSIONS

Overactive bladder is a manageable condition, with first-line treatment options including antimuscarinics, beta-3 agonists, and posterior tibial nerve stimulation. Second-line options include Onabot-A bladder injections or SNS. The choice of therapies should be guided by individual patient factors.

PATIENT SUMMARY

Overactive bladder is a manageable condition. All patients should be informed and advised on conservative treatment measures in the first instance. The first-line treatment options for its management include antimuscarinics or beta-3 agonists medication, and posterior tibial nerve stimulation procedures. The second-line options include onabotulinumtoxin-A bladder injections or sacral nerve stimulation procedure. The therapy should be chosen based on individual patient factors.

Closed-loop sacral neuromodulation for bladder function using dorsal root ganglia sensory feedback in an anesthetized feline model

Overactive bladder patients suffer from a frequent, uncontrollable urge to urinate, which can lead to a poor quality of life. We aim to improve open-loop sacral neuromodulation therapy by developing a conditional stimulation paradigm using neural recordings from dorsal root ganglia (DRG) as sensory feedback. Experiments were performed in 5 anesthetized felines. We implemented a Kalman filter-based algorithm to estimate the bladder pressure in real-time using sacral-level DRG neural recordings and initiated sacral root electrical stimulation when the algorithm detected an increase in bladder pressure. Closed-loop neuromodulation was performed during continuous cystometry and compared to bladder fills with continuous and no stimulation. Overall, closed-loop stimulation increased bladder capacity by 13.8% over no stimulation (p < 0.001) and reduced stimulation time versus continuous stimulation by 57.7%. High-confidence bladder single units had a reduced sensitivity during stimulation, with lower linear trendline fits and higher pressure thresholds for firing observed during stimulation trials. This study demonstrates the utility of decoding bladder pressure from neural activity for closed-loop control of sacral neuromodulation. An underlying mechanism for sacral neuromodulation may be a reduction in bladder sensory neuron activity during stimulation. Real-time validation during behavioral studies is necessary prior to clinical translation of closed-loop sacral neuromodulation.

The science behind programming algorithms for sacral neuromodulation

AIM

Sacral neuromodulation (SNM) is a widely adopted treatment for overactive bladder, non-obstructive urinary retention and faecal incontinence. In the majority, it provides sustained clinical benefit. However, it is recognized that, even for these patients, stimulation parameters (such as amplitude, electrode configuration, frequency and pulse width) may vary at both initial device programming and at reprogramming, the latter often being required to optimize effectiveness. Although some recommendations exist for SNM programming, the scientific data to support them are understood by few clinicians.

METHODS

This is a narrative review of the literature covering some of the science behind stimulating a mixed peripheral nerve and available preclinical data in the field of SNM. It covers electrode configuration, amplitude, frequency, pulse width and cycling considerations. The review is targeted at clinicians with an interest in the field and does not seek to provide exhaustive detail on basic neuroscience.

RESULTS AND CONCLUSIONS

Knowledge of the science of neuromodulation provides some guiding principles for programming but these are broad. These principles are not refuted by preclinical data but specific parameters in clinical use are not strongly supported by animal data, even after the limitations of small and large animal models are considered. The review presents a shortlist of programming principles on a theoretical basis but acknowledges that current practice is as much derived from evolved experience as science.

Stimulation Parameters for Sacral Neuromodulation on Lower Urinary Tract and Bowel Dysfunction-Related Clinical Outcome: A Systematic Review

Objective

Sacral neuromodulation (SNM) has been used to treat patients with lower urinary tract dysfunction and bowel dysfunction for many years. Success rates vary between 50% and 80%, indicating that there is much room for improvement. Altering stimulation parameters may result in improved outcome. This paper reports a systematic review of the clinical efficacy of nonconventional stimulation parameters on urinary tract and bowel dysfunction.

Materials and Methods

Three databases were used for the literature search: Ovid (Medline, Embase) and PubMed. Papers were screened by two independent reviewers, who also extracted data from these papers. Clinical papers studying SNM stimulation parameters, that is, intermittent stimulation, frequency, pulse width, and amplitude, in urinary tract and bowel dysfunction were included. Quality of included papers was assessed using standardized guidelines.

Results

Out of 5659 screened papers, 17 papers, studying various stimulation parameters, were included. Overall quality of these papers differed greatly, as some showed no risk of bias, whereas others showed high risk of bias.

Stimulation parameters included intermittent stimulation, frequency, pulse width, amplitude, and unilateral vs. bilateral stimulation. Especially high frequency SNM and either a narrow or wide pulse width seem to improve efficacy in patients with bowel dysfunction. Additionally, implementation of short cycling intervals is promising to improve quality of life for patients with urinary tract or bowel dysfunction.

Conclusion

The results of our systematic review indicate that stimulation parameters may improve efficacy of SNM in treatment of both urinary tract dysfunction and bowel dysfunction.

Programming Algorithms for Sacral Neuromodulation: Clinical Practice and Evidence-Recommendations for Day-to-Day Practice

Background

In sacral neuromodulation (SNM), stimulation programming plays a key role to achieve success of the therapy. However to date, little attention has been given to the best ways to set and optimize SNM programming during the test and chronic stimulation phases of the procedure.

Objective

Standardize and make SNM programming easier and more efficient for the several conditions for which SNM is proposed.

Methods

Systematic literature review and collective clinical experience report.

Results

The basic principles of SNM programming are described. It covers choice of electrode configuration, stimulation amplitude, pulse frequency and pulse widths, while use of cycling is also briefly discussed. Step‐by‐step practical flow charts developed by a group of 13 European experts are presented.

Conclusions

Programming of SNM therapy is not complex. There are few programming settings that seem beneficial or significantly impact patient outcomes. Only four basic electrode configurations could be identified according to four different options to define the cathode. In a majority of patients, the proposed stimulation parameters will allow a satisfactory improvement for long periods of time. A regular follow‐up is, however, necessary to assess and eventually optimize results, as well as to reassure patients.

Electrical stimulation in the treatment of bladder dysfunction: technology update

The urinary bladder has two functions: urine storage and voiding. Clinically, two major categories of lower urinary tract symptoms can be defined: storage symptoms such as incontinence and urgency, and voiding symptoms such as feeling of incomplete bladder emptying and slow urinary stream. Urgency to void with or without incontinence is called overactive bladder (OAB). Slow urinary stream, hesitancy, and straining to void with the feeling of incomplete bladder emptying are often called underactive bladder (UAB). The underlying causes of OAB or UAB can be either non-neurogenic (also referred to as idiopathic) and neurogenic, for example due to spinal cord injury or multiple sclerosis. OAB and UAB can be treated conservatively by lifestyle intervention or medication. In the case that conservative treatment does not provide sufficient benefit, electrical stimulation can be used. Sacral neurostimulation or neuromodulation (SNM) is offered as a third-line therapy to patients with non-neurogenic OAB or UAB. In SNM, the third or fourth sacral nerve root is stimulated and after a test period, a neuromodulator is implanted in the buttock. Until recently only a non-rechargeable neuromodulator was approved for clinical use. However, nowadays, a rechargeable sacral neuromodulator is also on the market, with similar safety and effectiveness to the non-rechargeable SNM system. The rechargeable device was approved for full body 1.5T and 3T MRI in Europe in February 2019. Regarding neurogenic lower urinary tract dysfunction, electrical stimulation only seems to benefit a selected group of patients.

Efficacy and mechanism of sub-sensory sacral (optimised) neuromodulation in adults with faecal incontinence: study protocol for a randomised controlled trial

Background

Faecal incontinence (FI) is a substantial health problem with a prevalence of approximately 8% in community-dwelling populations. Sacral neuromodulation (SNM) is considered the first-line surgical treatment option in adults with FI in whom conservative therapies have failed. The clinical efficacy of SNM has never been rigorously determined in a trial setting and the underlying mechanism of action remains unclear.

Methods/design

The design encompasses a multicentre, randomised, double-blind crossover trial and cohort follow-up study. Ninety participants will be randomised to one of two groups (SNM/SHAM or SHAM/SNM) in an allocation ratio of 1:1. The main inclusion criteria will be adults aged 18–75 years meeting Rome III and ICI definitions of FI, who have failed non-surgical treatments to the UK standard, who have a minimum of eight FI episodes in a 4-week screening period, and who are clinically suitable for SNM. The primary objective is to estimate the clinical efficacy of sub-sensory SNM vs. SHAM at 32 weeks based on the primary outcome of frequency of FI episodes using a 4-week paper diary, using mixed Poisson regression analysis on the intention-to-treat principle. The study is powered (0.9) to detect a 30% reduction in frequency of FI episodes between sub-sensory SNM and SHAM stimulation over a 32-week crossover period.

Secondary objectives include: measurement of established and new clinical outcomes after 1 year of therapy using new (2017 published) optimised therapy (with standardised SNM-lead placement); validation of new electronic outcome measures (events) and a device to record them, and identification of potential biological effects of SNM on underlying anorectal afferent neuronal pathophysiology (hypothesis: SNM leads to increased frequency of perceived transient anal sphincter relaxations; improved conscious sensation of defaecatory urge and cortical/subcortical changes in afferent responses to anorectal electrical stimulation (main techniques: high-resolution anorectal manometry and magnetoencephalography).

Discussion

This trial will determine clinical effect size for sub-sensory chronic electrical stimulation of the sacral innervation. It will provide experimental evidence of modifiable afferent neurophysiology that may aid future patient selection as well as a basic understanding of the pathophysiology of FI.

Trial registration

International Standard Randomised Controlled Trial Number: ISRCTN98760715. Registered on 15 September 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2689-1) contains supplementary material, which is available to authorized users.

Neuromodulation and female pelvic disorders

PURPOSE OF REVIEW

Sacral neuromodulation is a Food and Drug administration approved therapy for the treatment of refractory overactive bladder, urinary retention, and fecal incontinence. The objective of this manuscript is to review the recent literature regarding clinical outcome data and current management strategies for sacral neuromodulation.

RECENT FINDINGS

There have been significant advances in therapy techniques as well as long-term data supporting this therapy for both urinary and fecal incontinence. These include the InSite trial and the long-term follow-up of the fecal incontinence registry trial. In addition, the development of surgical techniques to reduce infection, improvements in programmability of the implantable pulse generator, as well as deciding on best stimulation parameters will be discussed. Finally, introduction of a new animal model to test a chronically implanted lead and stimulator in a large animal model opens the door to many future studies.

SUMMARY

These data help to inform us on the most recent clinical outcomes for sacral neuromodulation, as well as recommendations for best practices for implant technique.

Intermittent sacral neuromodulation for idiopathic urgency urinary incontinence in women

AIMS

SNM has been proven to be effective in the treatment of refractory UUI. Total costs and patient burden due to regular battery changes may prevent broad implementation of this treatment. The aim was to achieve a minimal improvement of 50% in incontinence episodes compared to pre-SNM by using iSNM.

METHODS

This prospective cohort study was performed in women with UUI receiving treatment with SNM for a minimum of 6 months. The neurostimulator was programmed to 8 hr "on" and 16 hr "off" per day for 12 weeks. Prior to iSNM, data were collected during no SNM and cSNM. Bladder diaries and various patient reported outcome measures were collected at predetermined time points: 1-5 weeks, and 8, 12, and 16 weeks. Nonparametric tests were used for the statistical analysis.

RESULTS

Of the 19 patients 63% showed an improvement of >50% of incontinence episodes during iSNM compared to pre-SNM. Bladder diary parameters showed a difference between pre-SNM and iSNM median (P-value); incontinence episodes/24 hr, 4.1-1.0 (P = 0.04), incontinence severity, 2.0-1.0 (P = 0.001), voiding episodes/24 hr, 13.0-8.0 (P = 0.001), and voided volume, 149-219 ml (P = 0.04). The UDI-6, 50.0-27.8 (P = 0.03), and the IIQ-7 scores, 50.0-9.5 (P = 0.04) also showed a significant improvement. No difference was demonstrated between iSNM and cSNM.

CONCLUSIONS

Compared to pre-SNM parameters, iSNM shows an improvement in both objective and subjective outcomes. Specifically no difference was found between iSNM and cSNM, indicating that iSNM could be a feasible and cost-effective alternative. Neurourol. Urodynam. 36:385-389, 2017. © 2015 Wiley Periodicals, Inc.