Sacral Neuromodulation in Women With Idiopathic Detrusor Overactivity Incontinence: Decreased Overactivity but Unchanged Bladder Contraction Strength and Urethral Resistance During Voiding

[Neurogenic, non-obstructive urinary retention: diagnosis and treatment]

Neurogenic, non-obstructive urinary retention has a varied aetiology. The condition can be caused by central-nervous diseases as well as by disorders of the peripheral nervous system. The formation of residual urine may lead to considerable problems that can have a significant impact on a patient's everyday life. A treatment appropriate for the lower urinary tract dysfunction and suited to the patient's situation in life is only possible if a differentiated diagnostic evaluation has been performed. Both conservative and surgical therapeutic strategies are available, while drug treatment approaches are less relevant. Neuromodulative procedures are particularly suitable for causal treatment of the dysfunction. For patients requiring artificial bladder voiding, intermittent self-catheterization is generally preferable to using an indwelling catheter.

Effects of repetitive functional magnetic stimulation in the sacral nerve in patients with neurogenic detrusor overactivity after suprasacral spinal cord injury: a study protocol for a randomized controlled trial

BACKGROUND

Neurogenic detrusor overactivity (NDO) is a serious and common complication after spinal cord injury, affecting patients' quality of life seriously. Therefore, we developed this research protocol to evaluate the efficacy of repetitive functional magnetic stimulation (rFMS) in the sacral nerve in patients with neurogenic detrusor overactivity (NDO) after suprasacral spinal cord injury (SCI) and provide more options for rFMS in treating NDO after suprasacral SCI.

METHODS

This study is a single-center, randomized, parallel-group clinical trial. We will recruit the patients with NDO after suprasacral SCI in the Rehabilitation Department of the Affiliated Hospital of Southwest Medical University from September 2022 to August 2023. They will be assigned to the rFMS group and the sham stimulation group randomly. The sample size is 66, with 33 patients in each group. The rFMS group will receive real rFMS treatment of the sacral nerve (100% stimulation intensity, 5 Hz, 20 min each time, five times a week), and the sham group will receive sham stimulation. Both groups will receive similar treatment strategies, including medication, standard urine management, acupuncture treatment, and health education. The bladder compliance (bladder capacity/detrusor pressure) and pudendal nerve electromyography will be evaluated at baseline, 8th week of treatment. The residual volume of the bladder and bladder diary will be recorded once a week during 8 weeks of treatments. SCI-QOL and NBSS will be evaluated at baseline, the 4th and 8th week of treatment. In addition, the above assessments will be followed up at 8 weeks after the end of treatment.

DISCUSSION

It is expected that the bladder function, symptoms, and quality of life might be significantly improved after rFMS of the sacral nerve.

TRIAL REGISTRATION

The China Clinical Trials Registry has approved this study, registration number: ChiCTR2100045148. Registered on April 7, 2021.

Physical Agent-Based Treatments for Overactive Bladder: A Review

Almost one-fifth of the people in the world experience a decrease in quality of life due to overactive bladder (OAB) syndrome. The main bothersome symptoms are urgency accompanied by urinary frequency and nocturia. This chronic, disabling condition is first managed by reducing fluid intake and pelvic floor muscle training, supplemented with antimuscarinic drugs, if necessary. However, refractory cases often still occur. In more severe cases, invasive surgical interventions can be considered; yet, the success rate is still inconsistent, and there is a high complication rate. This condition is frustrating for patients and challenging for the medical staff involved. Although its pathophysiology has not been fully elucidated, peripheral autonomic somatic and sensory afferent receptors are considered to be involved in this condition. Hence, currently, physical agent-based treatments such as neuromodulation have taken a significant place in the third-line therapy of OAB. The efficacy and safety profiles of electrical and magnetic stimulation continue to evolve. Physical-based agents provide an appealing option owing to their effectiveness and minimal side effects. In addition, more physical therapies using light and shock energy are currently being investigated. Thus, a comprehensive understanding of these modalities is an extremely important aspect to provide the most suitable modalities for patients.

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.

[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.

Sacral Neuromodulation: Mechanism of Action

Although the mechanism of action of sacral neuromodulation (SNM) is still not fully elucidated, it seems to involve modulation of spinal cord reflexes and brain networks by peripheral afferents according to findings from neurophysiology, electroencephalography, positron emission tomography, and magnetic resonance imaging studies. Moreover, motor effects mediated via efferents on direct stimulation cannot be fully excluded. In this mini-review, we summarize current knowledge on the mechanism of action of SNM. PATIENT SUMMARY: We reviewed the literature on the mechanism of action of sacral neuromodulation, in which electrical stimulation is applied to the nerves that regulate bladder activity. The mechanism seems to involve modulation of spinal cord reflexes and brain networks by peripheral sensory and possibly motor neurons.

Acute effect of sacral neuromodulation for treatment of detrusor overactivity on urodynamic parameters

Aim

The aim of this study is to evaluate the acute effects of sacral neuromodulation (SNM) on various urodynamic parameters.

Methods

Patients with overactive bladder and detrusor overactivity (DO) who were planned for percutaneous nerve evaluation (PNE) were included. Directly after the PNE, a urodynamic study (UDS) was performed. The stimulation was turned off during the first UDS (UDS 1), and during the second filling cycle, stimulation was turned on (UDS 2). The UDS was followed by a test phase of 1 week and the bladder diaries were evaluated during an outpatient clinic visit. Primary outcome measures were the differences in UDS parameter values with SNM off and on.

Results

Ten female patients were included in the study and completed the study protocol. Eight patients showed ≥50% improvement of symptoms following a test phase. There were no differences between UDS 1 and UDS 2 in the UDS parameters; bladder volume at first sensation, bladder volume at first DO, highest DO pressure, bladder capacity, maximum flow rate, and pressure at maximum flow rate.

Discussion

None of the aforementioned urodynamic parameters was influenced by acute SNM in patients who responded to SNM. To the best of our knowledge, this is the first study investigating the acute effects of SNM on bladder function.

Predicting a successful outcome in sacral neuromodulation testing: Are urodynamic parameters prognostic?

AIMS

To assess whether the urodynamic parameters of mean voided volume, peak detrusor overactivity (DO) pressure, bladder compliance, capacity, and volume at first detrusor overactivity during filling cystometry can predict a successful outcome at first stage tined lead placement (FSTLP).

METHODS

Ninty-nine consecutive patients with urodynamically proven idiopathic detrusor overactivity (IDO) refractory to medical treatment and opting for Sacral Nerve Stimulation (SNS), were assessed pre and post FSTLP. Data from 3-day frequency-volume charts, and patient reported (subjective) outcomes were used to assess success or failure after FSTLP. Success was defined as improvement in symptoms >50%. Binary logistic regression analysis was used to ascertain whether key parameters at filling cystometrogram were predictors for success prior to FSTLP.

RESULTS

Binary logistic regression analysis did not demonstrate any significant relationship between the five parameters at urodynamics and outcome at FSTLP (B < 0.01, P > 0.16) for all parameters.

CONCLUSIONS

The results from this prospective analysis on patients with IDO refractive to medical therapy referred for SNS would suggest that aside from proving DO at urodynamics as a pre-requisite for intervention as per NICE and EAU guidelines, no parameter is predictive for a successful outcome at FSTLP.

Long-Term Functional Outcomes of S3 Sacral Neuromodulation for the Treatment of Idiopathic Overactive Bladder

OBJECTIVES

To assess the long-term functional outcomes of sacral neuromodulation (SNM) in the treatment of refractory idiopathic overactive bladder (IOAB) and to determine predictive factors for success.

MATERIALS AND METHODS

To obtain long-term data, all consecutive patients suffering from IOAB and treated by SNM at a single tertiary care center between December 1996 and December 2004 were included. Data regarding patient demographics, past medical, and surgical history, bladder diary, complications as well as device revision and removal rates were collected. Success was defined as an improvement ≥ 50% of any clinical parameter.

RESULTS

Overall, 34 patients, with a median age of 57.8 years (IQR 44.8-65.7) were included. Immediately after definitive implantation, 2 (6%) patients were lost to follow-up. After a median follow-up of 9.7 years (IQR 4.7-12.0), SNM was considered successful in 20 (63%) patients. Mean amount of protections used per 24 hours significantly decreased (4.1 preoperatively vs. 1.8 at the last follow-up visit, p = 0.02). Devices were removed in 2 (6%) patients due to pain and lack of efficacy. Twenty-two revision surgeries were performed in 15 (47%) patients. First revision surgery occurred after a mean of 6.2 years (± 3.1). Revision surgeries were mainly performed for end of battery life/device dysfunction (n = 18, 82%). No significant predictor for success was identified.

CONCLUSIONS

With a median follow-up time of 9.7 years, this retrospective SNM study reports a 63% efficacy rate (≥ 50% improvement) for the treatment of refractory IOAB. Moreover, it is a well-tolerated and minimally invasive therapy.

[Botulinum toxin versus sacral neuromodulation for idiopathic detrusor overactivity]

Idiopathic detrusor overactivity (motory urge) negatively affects the live of patients. Conservative treatment is not always effective and has multiple side effects. Sacral neuromodulation is a second line therapy for the treatment of idiopatic detrusor overactivity. Over the last decade, botulinum toxin injections have been increasingly used as alternative although there are only few randomized studies. Goal of this review is to compare efficiacy, safety and cost effectiveness of both methods.

[Sacral neuromodulation for neurogenic bladder dysfunction]

Sacral neuromodulation (SNM) represents a promising option for managing treatment-refractory neurogenic bladder dysfunction. It remains to be seen, however, which types of neurogenic bladder dysfunction and which underlying neurological disorders best respond to SNM. Constant improvements in SNM have been achieved and it is now a minimally invasive approach performed under local anesthesia which should be considered before undertaking larger reconstructive procedures. An electrode is implanted in the S3 or S4 sacral foramen and during a test phase lasting for days to weeks the patient keeps a bladder diary to determine whether SNM has provided a relevant benefit. If the results of the test phase are positive, a neuromodulator is implanted in the gluteal area (or more rarely in the abdominal wall).The mechanism of action of SNM has not been completely clarified, but the afferent nerves most likely play a key role. It appears that SNM produces a modulation of medullary reflexes and brain centers by peripheral afferents. The implanted neuromodulation system does not lead to limitation of the patient's activities. However, it should be noted that high-frequency diathermy and unipolar electrocauterization are contraindicated in patients with neuromodulators, that during extracorporeal shock wave lithotripsy the focal point should not be in the direct vicinity of the neuromodulator or the electrode, that ultrasound and radiotherapy in the region of the implanted components should be avoided, that the neuromodulation should be discontinued in pregnancy, and that MRI examinations should only be conducted when urgently indicated and the neuromodulator is turned off.

Sacral neuromodulation for lower urinary tract dysfunction

OBJECTIVES

To review the technique, indications, results and working mechanisms of sacral neuromodulation (SNM) for lower urinary tract dysfunction.

METHODS

The available literature on SNM for lower urinary tract dysfunction was searched. Based on the information available in the literature and also based on personal experience, the urological indications, technique, mechanisms of action and results of SNM are presented and discussed.

RESULTS

SNM for lower urinary tract dysfunction involves stimulation of the 3rd sacral nerve with an electrode implanted in the sacral foramen and connected to a pulse generator. The technique is accepted by the FDA since 1997. Currently, SNM for lower urinary tract dysfunction has been successfully used in about 26,000 patients with various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. The actual procedure of SNM consists of a minimal invasive technique and is effective in about 70% of the patients who have been implanted with a permanent system. Also, in pelvic pain, interesting results have been described. SNM modulates the micturition reflexes at different levels in the central nervous system.

CONCLUSIONS

Sacral neuromodulation is a safe and effective therapy for various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. It should be the first choice after failure of maximal conservative therapy.

Sacral nerve stimulation: neuromodulation for voiding dysfunction and pain

Voiding dysfunction, which includes incontinence, retention, and chronic pelvic pain, is a relatively frequent problem that can be difficult to manage. Neuromodulation via stimulation of the sacral nerves has been shown to improve these symptoms, although the exact mechanisms remain elusive. Techniques for nerve stimulation may vary, depending on the disease, location of pain, and the patient's anatomy. In addition to placement of electrodes on the sacral nerve roots, modulation has also been reported by peripheral branches of the sacral nerves including the pudendal and posterior tibial nerves. Newer surgical techniques have significantly decreased the morbidity of the procedures and increased the probability of a successful outcome.

Refractory overactive bladder in men: update on novel therapies

Overactive bladder (OAB) in men is an entity that may be challenging to diagnose and treat, especially in the presence of bladder outlet obstruction. The application of oral medical treatments of lower urinary tract symptoms attributed to benign prostatic hyperplasia has traditionally utilized alpha-adrenergic blockers and 5alpha-reductase inhibitors. After failure of oral medical therapies, surgical options are traditionally offered. Even after surgical options are successful, lower urinary tract symptoms that are secondary to OAB persist. These patients merit a trial of antimuscarinic drugs. Additionally, certain patients with concomitant bladder outlet obstruction who have not been surgically relieved can still merit a trial of antimuscarinic drugs without significant risk of developing urinary retention. When these oral antimuscarinic drugs fail, options still remain for treating men with refractory OAB. Successful application of various diagnostic approaches and the initiation of conservative options as well as other options, such as neuromodulation for refractory urgency and urge incontinence, can help the patient. Finally, emerging data support the use of intradetrusor injections of botulinum toxin for refractory OAB.

Functional obstructed voiding in the neurologically normal patient

Voiding dysfunction is common and often is the result of urethral obstruction to urine flow. Obstruction can be due to failure of the sphincteric mechanism to sufficiently relax. Such functional obstructions may have smooth and/or striated muscle components. Identifying and characterizing functional bladder outlet obstruction enables the physician to effectively treat these symptomatic patients.