Long-term outcome of sacral neuromodulation in patients with idiopathic nonobstructive urinary retention: Single-center experience

Systematic review and meta-analysis of urinary incontinence prevalence and population estimates

INTRODUCTION

Incontinence impacts the quality-of-life of people suffering from the disease. However, there is limited information on the prevalence of incontinence due to the stigma, lack of awareness, and underdiagnosis.

OBJECTIVE

This study aims to conduct a systematic review and meta-analysis of overactive bladder (OAB) and nonobstructive urinary retention (NOUR).

METHODS

The authors conducted a systematic review following the PRISMA guidelines using Embase, MEDLINE, and PubMed databases to identify the relevant publications in the English language. Two reviewers independently assessed the articles and extracted the data. Review papers were assessed for content and references. A meta-analysis of proportions was conducted using the RStudio software. To address the age heterogeneity, a subanalysis was conducted. Pooled data were overlayed on the Canadian population and a sample of 10 populous countries to estimate the number of people suffering from incontinence.

RESULTS

Twenty-eight and eight articles were selected for OAB and NOUR, respectively. The pooled prevalence of OAB in men and women was 12% (95% CI: 9%-16%) and 15% (95% CI: 12%-18%), respectively. The estimated prevalence of NOUR was 15.6%-26.1% of men over 60 and 9.3%-20% of women over 60. The subanalysis pooled prevalence of OAB in men and women was 11% (95% CI: 8%-15%) and 12% (95% CI: 9%-16%), respectively. We estimated that 1.4-2.5 million women and 1.3-2.2 million men suffer from OAB in Canada.

CONCLUSION

Urinary incontinence is an under-reported and underdiagnosed prevalent condition that requires appropriate treatment to improve a patient's quality-of-life.

[Sacral neuromodulation for bladder voiding dysfunction: Experience at a French university center]

OBJECTIVE

To report the experience of a university hospital center with sacral neuromodulation for patients with bladder voiding disorders.

MATERIAL AND METHODS

All patients who underwent sacral neuromodulation between 1998 and 2022 for bladder voiding disorders were included. Medical records were analyzed retrospectively, and population, efficacy and follow-up data were collected.

RESULTS

A total of 134 patients underwent test implantation and 122 patients were analyzed. 68 patients (56%) were implanted with a definitive neuromodulation device. Mean age was 43±16 years and BMI 25.5±5.4kg/m2. 74% were women. Bladder voiding disorder was due to sphincter hypertonia in 51% of cases, with associated bladder hypocontractility in 29%. The spontaneous micturition rate after implantation increased from 34% to 92%. Implantation results appeared to be better in patients with sphincter hypertonia, whether or not associated with bladder hypocontractility. The benefit was most often present with a frequency of 5Hz (54.4%). Side-effects were present in 52% of cases at 5 years, and in 85% of cases were pain in relation to the implanted devices. They resolved under medical treatment or after revision of the device (27% of cases at 5 years).

CONCLUSION

SNM is effective in micturition recovery, but has side effects. Urodynamic mechanism and etiology may provide clues for modulating NMS box settings and determining predictive factors for NMS success. Data from other centers are needed to identify reliable predictive factors.

Sacral neuromodulation in patients with detrusor underactivity: Is biological sex an indicator?

OBJECTIVES

This study aimed to report sacral neuromodulation (SNM) outcomes in detrusor underactivity (DU).

METHODS

A multicentric, multinational, retrospective case series was conducted between March 2017 and June 2021 in three different referral centers. Initial test phase stimulation included either a percutaneous nerve evaluation (PNE) or an advanced lead evaluation test phase (ALTP) before permanent SNM implantation. The test phases were performed under local anesthesia, either in the outpatient (PNE) or operating room (ALTP), in the prone position, which was implanted in the third or fourth sacral foramina under fluoroscopic guidance. Patients with favorable response to the initial test phase during the first 2 weeks underwent the implantable pulse generator (IPG) implantation (Medtronic neurostimulation generator device InterStim™). Favorable response was defined as ≥ 50% improvement in symptoms, frequency of clean intermittent catheterization (CIC) and/or decrease in postvoid residual (PVR), increase in voided volume, or improvement in bladder voiding efficiency (BVE) based on the bladder diary.

RESULTS

Fifty-eight patients were recruited with a mean age of 39.95 ± 15.28 years. Among the 58 cases, 36 (62.1%) patients responded to the initial stage. Of these, 12 patients (30.8%) with non-neurogenic etiology and nine patients (52.9%) with neurologic etiology did not respond to the initial test phase; thus, they did not undergo full implantation (p = 0.141). Voided volume, PVR, and the median maximum flow rate (Qmax) improved significantly (p < 0.001) in both sexes; however, there was no statistical difference between both genders. Most female cases (78.3%), and nearly half of the men (51.4%), responded to the test phase and were candidates for the IPG phase. Among the 35 cases who underwent IPG, 27 patients (72.2% of males, and 77.8% of females; p = 0.700) had a favorable response to IPG. 46.6% of patients had a successful outcome at the end of the study.

CONCLUSION

This multicentric study showed that SNM effectively and safely provided symptom improvement in refractory DU in males similar to females which is an important finding as previously it has been suggested that SNM works better in nonobstructive urinary retention in women and not in women.

Efficacy of sacral neuromodulation and percutaneous tibial nerve stimulation in the treatment of chronic nonobstructive urinary retention: A systematic review

AIM

The aim of this systematic review is to provide an updated report on the efficacy and complications of sacral neuromodulation (SNM) and percutaneous tibial nerve stimulation (PTNS) in the treatment of chronic nonobstructive urinary retention (CNOUR), with a focus on the contemporary technique of SNM utilizing the percutaneous placement of tined leads.

METHODS

This systematic review was conducted with the use of PRISMA guidelines and registered with PROSPERO (CRD42020208052). A systematic literature search was conducted in Embase, PubMed, and Cochrane databases. Inclusion criteria include English language and human participants. Exclusion criteria include SNM studies involving less than 10 CNOUR patients, studies containing data obtained using open, surgical implantation of nontined leads, and studies that only reported the test phase success rate with no long-term efficacy data. The risk of bias assessment was conducted using the National Institutes of Health study quality assessment tool.

RESULTS

A total of 16 papers studies were included (11 SNM and 5 PTNS) in this review. The success rate for SNM ranges between 42.5% and 100% (median = 79.2%) for the test stimulation phase and 65.5%-100% (median = 89.1%) in the long term. Most SNM studies reported revision and explantation rates of lesser than 20%. The success rate was much lower for PTNS, in the 50%-60% range and complications were minimal.

CONCLUSION

SNM using the contemporary percutaneous tined lead implantation technique appears to be an effective treatment for CNOUR and is durable in the long term. Compared to SNM, PTNS appears less efficacious with less evidence supporting its use in CNOUR. Further prospective studies are required to define the role of PTNS in the treatment of CNOUR.

Fowler's Syndrome-The Cause of Urinary Retention in Young Women, Often Forgotten, but Significant and Challenging to Treat

Urinary retention in young women is a relatively rare clinical problem and is often underdiagnosed. In particular, functional causes of urinary retention pose a diagnostic challenge. One of them is Fowler’s syndrome, which is associated with impaired urethral relaxation. Fowler’s syndrome is characterized by a large bladder capacity, reduced sensation, increased maximal urethral closure pressure, and detrusor underactivity. Several hypotheses have arisen to explain the cause of urethral relaxation disorders: hormonal changes characteristic of Polycystic Ovary Syndrome (PCOS), causing abnormal stabilization of the muscle membrane, primary failure of relaxation of the striated muscle of the urethra sphincter, and increased urethral afferent activity, inhibiting the bladder afferent signals from reaching the brain by potentiating a spinal mechanism of urinary continence. Currently, sacral neuromodulation is the only intervention that can restore an atypical voiding pattern in women with Fowler’s syndrome. The therapeutic effectiveness exceeds 70%, although the revision rate is relatively high, exceeding 50%. Well-designed, long-term prospective studies comparing sacral neuromodulation (SNM) with other therapies such as pelvic floor muscle physiotherapy are warranted to offer the best patient-tailored treatment.

Application of ultrasound during electrode implantation for sacral neuromodulation in patients with neurogenic bladder secondary to spinal cord disease: a retrospective study

PURPOSE

To compare the use of intraoperative ultrasound with X-ray fluoroscopy during sacral neuromodulation lead electrode placement in patients with neurogenic bladder secondary to spinal cord disease.

METHODS

We reviewed the medical records of 52 patients who underwent sacral neuromodulation (SNM) lead electrode implantation under fluoroscopy or ultrasound guidance from July 2016 to July 2019. The operating time, number of electrode contacts with stimulus responses, minimum voltage that causes a stimulus response, and rate of standard lead electrode placement were used to assess the differences between the two methods. All patients were evaluated by recording bladder diaries, postvoid residual volumes before and during the testing period. Permanent SNM implantation is acceptable if symptoms improve by at least 50%.

RESULTS

The operating time decreased from 87.1 ± 25.19 min in the X-ray group to 68.2 ± 25.20 min (p < 0.05) in the ultrasound group. The number of electrode contacts with stimulus responses, rate of standard lead electrode placement, and implantable pulse generator (IPG) placement rate were not significantly different between the two groups (p > 0.05). There was no radiation exposure during the operation in the ultrasound group. No incisional infections, hematomas, or other critical complications were reported in either groups.

CONCLUSION

Ultrasound can be applied to safely place lead electrode for sacral neuromodulation and leads to no radiation exposure to the patient, surgeon, and operating room staff and a shortened operating time while maintaining the same efficacy as X-ray.

Evaluation of progression from first to second stage sacral neuromodulation and unplanned device removal

OBJECTIVE

Sacral neuromodulation (SNM) is an advanced treatment option for patients with refractory overactive bladder (OAB) symptoms, urinary retention, and bowel disorders; it is usually performed in 2 separate procedures. This study aims to determine a cohort's progression rate from stage 1 to 2 and predict factors for progression and unplanned device removal or revision.

MATERIAL AND METHODS

A retrospective review was conducted in patients who underwent SNM at a single institution between June 2012 and May 2019. Progression rates from stage 1 to 2, patient characteristics, and indications for unplanned SNM removal or revision were recorded. Chi-square, Mann-Whitney U, and Fisher's exact tests were used for data analysis.

RESULTS

A total of 128 patients underwent SNM for 1 or more of the following diagnoses: OAB (n=103), urinary retention (n=15), neurogenic bladder dysfunction (n=4), fecal incontinence (n=2), and constipation (n=4). The progression rate to stage 2 was 92.2% (118/128). Patients who failed to progress to stage 2 had additional diagnoses other than OAB, such as urinary retention or bowel disorders (p=0.007). Fifteen patients (12.7%) required SNM removal or revision within 4 years of surgery. Among these patients, the body mass index was significantly lower (p=0.036).

CONCLUSION

Most patients (92.2%) progressed to stage 2. Patients with only OAB symptoms had a higher progression rate to stage 2. Single full-stage procedures may be considered in select patients to reduce morbidity, time, and costs.

Underactive Bladder and Bladder Outlet Procedures in Women

Purpose of review

This review outlines current options for women suffering from both stress urinary incontinence (SUI) and underactive bladder (UAB). This is often a challenging patient population; however, many treatment options are available including behavioral, pharmacologic, and surgical. Therapies can be divided into those specifically targeting either the bladder or the bladder outlet.

Recent findings

For patients with SUI and UAB, several clinical trials have helped to formulate current guidelines. Also, a number of novel techniques and therapeutic agents are currently under investigation. Current surgical treatments frequently employed for SUI include midurethral slings and urethral bulking agents. In contrast, the current treatments for UAB are limited to either sacral neuromodulation in women with Fowlers syndrome or in the majority, clean intermittent catheterization. Recent studies have investigated the use of adjustable urethral slings and novel modes of neuromodulation with varying degrees of success.

Summary

Choosing the best treatment plan for SUI combined with UAB involves a thorough understanding of a patient's preferences and goals. Fortunately, women have many options that can significantly benefit their quality of life.

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.

What Is New in Neuromodulation?

Neuromodulation encompassing sacral and peripheral modalities is an established, effective, and safe higher-order treatment option approved in the USA for managing refractory overactive bladder, non-obstructive urinary retention, and fecal incontinence. This review highlights the most recent literature, indications, treatment durability, and the latest innovations in this field. Regarding sacral neuromodulation (SNM), recent work suggests improved parameters for optimal lead placement, increased data to support the lasting effects of treatment, and novel applications of this technology to other pelvic disorders. In addition, there are emerging technologies with smaller MRI compatible devices. Newer data on percutaneous tibial nerve stimulation (PTNS) suggests it may be more beneficial for certain patients. With new technology, implantable tibial nerve stimulators are ushering in a new frontier of nerve stimulation in the comfort of the patient's home.

Female underactive bladder - Current status and management

Underactive bladder (UAB) is defined by the International Continence Society as a symptom complex characterized by a slow urinary stream, hesitancy, and straining to void, with or without a feeling of incomplete bladder emptying sometimes with storage symptoms. Until recently, the topic has received little attention in the literature probably due to a lack of consistent definitions and diagnostic criteria. We performed a literature review to identify articles related to the diagnosis and management of UAB, specifically in female patients. UAB is a common clinical entity, occurring in up to 45% of females depending on definitions used. Prevalence increases significantly in elderly women and women who live in long-term care facilities. The exact etiology and pathophysiology for developing UAB is unknown, though it is likely a multifactorial process with contributory neurogenic, cardiovascular, and idiopathic causes. There are currently no validated questionnaires for diagnosing or monitoring treatment for patients with UAB. Management options for females with UAB remain limited, with clean intermittent catheterization, the most commonly used. No pharmacotherapies have consistently been proven to be beneficial. Neuromodulation has had the most promising results in terms of symptom improvement, with newer technologies such as stem-cell therapy and gene therapy requiring more evidence before widespread use. Although UAB has received increased recognition and has been a focus of research in recent years, there remains a lack of diagnostic and therapeutic tools. Future research goals should include the development of targeted therapeutic interventions based on pathophysiologic mechanisms and validated diagnostic questionnaires.

Results of Sacral Neuromodulation Therapy for Urinary Voiding Dysfunction: Five-Year Experience of a Retrospective, Multicenter Study in China

PURPOSE

This five-year, retrospective, multicenter study evaluated the long-term safety and efficiency of sacral neuromodulation (SNM) in Chinese patients with urinary voiding dysfunction.

PATIENTS AND METHODS

This is a Chinese national, multicenter, retrospective study that included 247 patients (51.2% female) who received an implantable pulse generator (IPG) (InterStim, Medtronic, Minneapolis, MN, USA) between 2012 and 2016. Success was considered if the initial ≥50% improvement in any of primary voiding diary variables persisted compared with baseline. The results were further stratified by identifying patients who showed >50% improvement and those although showed <50% improvement but still wanted to receive IPG; these data were collected and analyzed for general improvement.

RESULTS

Following test stimulation, 187 patients (43%) declined implantation and 247 (57%) underwent implantation using InterStim®. Among 247 patients, 34 (13.7%) had overactive bladder (OAB), 59 (23.8%) had interstitial cystitis/bladder pain syndrome (IC/BPS), 47 (19%) had idiopathic urinary retention (IUR), and 107 (44.1%) had neurogenic bladder (NB). IPG efficiency rate for OAB, interstitial cystitis/bladder pain syndrome, idiopathic urinary retention, and neurogenic bladder were 42.5, 72.4, 51.6, and 58.8%, respectively. The mean duration of follow-up was 20.1 ± 12.8 months.

CONCLUSIONS

SNM appears effective in the long term, with a total IPG implantation rate of approximately 57% (ranging between 42.5 and 72.4% depending on indication). Interstitial cystitis/bladder pain syndrome appear to be the best indication for stage I testing. Chinese neurogenic bladder patients are most inclined to choose SNM. SNM is relatively safe, with low postoperation adverse events of 16.1% and reoperation rate of 3.2% during the follow-up period.