Sacral neuromodulation for treatment of lower urinary tract dysfunction

Despite initial reservations, sacral neuromodulation has begun to develop as a new therapeutic tool for the treatment of lower urinary tract dysfunction. It bridges the gap between conservative treatment options and highly invasive procedures, such as urinary diversion. At present, there are no clinical variables that can reliably predict the efficacy of neuromodulation in an individual patient. All patients, regardless of indication, must therefore undergo a test stimulation before they can be offered chronic sacral neuromodulation with an implanted system. Evaluations in various clinical trials have confirmed that sacral neuromodulation, based on unilateral sacral foramen electrode implantation, has statistically significant therapeutic effects compared to controls, in patients with urge syndromes and failure to empty. The patients most likely to benefit from this treatment are those with detrusor hyperactivity or detrusor hypo-activity. Those with pain syndromes are less likely to respond and to benefit from treatment. Acute and subchronic sacral neuromodulation are associated with very low rates of complications. Complications of chronic sacral neuromodulation are caused either by surgery-related morbidity or hardware problems. Conservative treatment options should be exhausted before neuromodulation is considered. This rule has two purposes: First, it postpones surgery, with its potential morbidity, for as long as possible; second, the long-term efficacy of neuromodulation is still unclear and may be limited in some patients. A fully exploited conservative therapy, in combination with subsequent sacral neuromodulation, may therefore be the optimum way to pursue therapeutic options of relatively low invasiveness.     

Sacral neuromodulation and lower urinary tract dysfunction in cerebral palsy

Given the emerging role of sacral neuromodulation in treatment of neurogenic voiding dysfunction, the author describes the use of sacral neuromodulation in a patient with voiding dysfunction caused by cerebral palsy (CP). A 45-year-old patient with cerebral palsy presented with progressive complaints of urgency and overflow incontinence and was found to be in retention. She underwent sacral neuromodulation and had complete resolution of her symptoms. The literature of lower urinary tract dysfunction in CP is reviewed. It is concluded that sacral neuromodulation may be a valuable tool in treating storage and voiding disorders associated with CP.     

Sacral neuromodulation for neurogenic lower urinary tract dysfunction: systematic review and meta-analysis

Context

Treatment of neurogenic lower urinary tract dysfunction (LUTD) is a challenge, because conventional therapies often fail. Sacral neuromodulation (SNM) has become a well-established therapy for refractory non-neurogenic LUTD, but its value in patients with a neurologic cause is unclear.

Objective

To assess the efficacy and safety of SNM for neurogenic LUTD.

Evidence acquisition

Studies were identified by electronic search of PubMed, EMBASE, and ScienceDirect (on 15 April 2010) and hand search of reference lists and review articles. SNM articles were included if they reported on efficacy and/or safety of tested and/or permanently implanted patients suffering from neurogenic LUTD. Two reviewers independently selected studies and extracted data. Study estimates were pooled using Bayesian random-effects meta-analysis.

Evidence synthesis

Of the 26 independent studies (357 patients) included, the evidence level ranged from 2b to 4 according to the Oxford Centre for Evidence-Based Medicine. Half (n = 13) of the included studies reported data on both test phase and permanent SNM; the remaining studies were confined to test phase (n = 4) or permanent SNM (n = 9). The pooled success rate was 68% for the test phase (95% credibility interval [CrI], 50–87) and 92% (95% CrI, 81–98%) for permanent SNM, with a mean follow-up of 26 mo. The pooled adverse event rate was 0% (95% CrI, 0–2%) for the test phase and 24% (95% CrI, 6–48%) for permanent SNM.

Conclusions

There is evidence indicating that SNM may be effective and safe for the treatment of patients with neurogenic LUTD. However, the number of investigated patients is low with high between-study heterogeneity, and there is a lack of randomised, controlled trials. Thus, well-designed, adequately powered studies are urgently needed before more widespread use of SNM for neurogenic LUTD can be recommended.     

Sacral nerve stimulation for neuromodulation of the lower urinary tract

Patients with symptoms of overactive bladder syndrome or non-obstructive urinary retention, refractory to conservative therapy, can nowadays be treated minimally invasively with sacral nerve stimulation (SNS). The use of electric currents to treat urological pathology has a long history but SNS therapy only received FDA approval in 1997. The mechanisms of action are still not known so there are different theories explaining the modulation effect. Recent studies have shown a central modulation effect. Predictive factors which can help to identify the perfect candidates are not known. Over the years the technique of SNS has become less invasive and because of two stage implantation test results have proven to be more reliable. The clinical results for this therapy have proven to be safe and effective and with the technical improvements over the years the re-operation and complication rates have decreased significantly. The clinical results have led to expanding indications because of positive effects in other symptoms. In the field of urology this has resulted in the use of SNS therapy for interstitial cystitis, neurogenic lower urinary dysfunction, and pediatric voiding dysfunction. In the field of gastro-intestinal pathology, SNS therapy is used to treat faecal incontinence and constipation.     

Sacral neuromodulation for refractory lower urinary tract dysfunction: results of a nationwide registry in Switzerland

OBJECTIVE: To assess the efficacy and safety of sacral neuromodulation (SNM) in patients with refractory lower urinary tract dysfunction in Switzerland based on a nationwide registry. PATIENTS AND METHODS: A total of 209 patients (181 females, 28 males) underwent SNM testing between July 2000 and December 2005 in Switzerland. Subjective symptom improvement, bladder/pain diary variables, adverse events, and their management were prospectively registered. RESULTS: SNM testing was successful (defined as improvement of more than 50% in bladder/pain diary variables) in 102 of 209 patients (49%). An implantable pulse generator (IPG) was placed in 91 patients (89% of all successfully tested and 44% of all tested patients). Of the IPG-implanted patients, 71 had urge incontinence, 13 nonobstructive chronic urinary retention, and 7 chronic pelvic pain syndrome. After a median follow-up of 24 mo, SNM was successful in 64 of the 91 IPG-implanted patients (70%) but failed in 27 patients. SNM was continued in 15 of the 27 patients considered failures, because following troubleshooting SNM response improved subjectively and the patients were satisfied. However, improvement in bladder/pain diary variables remained less than 50%. In the other 12 patients both the leads and the IPG were explanted. During the test phase and during/following IPG implantation, 6% (12 of 209) and 11% (10 of 91) adverse event rates and 1% (3 of 209) and 7% (6 of 91) surgical revision rates were reported, respectively. CONCLUSIONS: SNM is an effective and safe treatment for refractory lower urinary tract dysfunction. Adverse events are usually transient and can be treated effectively.     

Sacral neuromodulation: an effective treatment for lower urinary tract symptoms in multiple sclerosis

Introduction and hypothesis

Most subjects with multiple sclerosis (MS) suffer from lower urinary tract symptoms (LUTS). Detrusor overactivity, detrusor hypocontractility and detrusor–sphincter dyssynergia are the most common bladder dysfunctions. Management is not straightforward due to the progressive course of the disease. Sacral neuromodulation (SNM) has received increasing attention among new effective treatments for bladder disorders associated with MS. The aim of this study was to review the published literature on the role of SNM in the treatment of LUTS in patients with MS.

Methods

A literature search was carried out up to December 2014, using relevant search terms in MEDLINE and EMBASE databases. The ClinicalTrials.gov and Controlled-trials.com online trial registries and the abstracts from international scientific meetings were searched for English-language studies containing relevant search terms. Relevant reviews and trials and prospective studies were analysed by two independent reviewers.

Results

Two prospective studies and four retrospective studies were included. Overall, MS patients represented small series (4 to 25 subjects). The longest follow-up was 7 years and the evaluation of the treatment outcomes was not homogeneous among the studies. The definition of objective cure was often unclear. The subjective cure rate was 45 %, patients’ reported satisfaction was 85 % and all the results were stable over time.

Conclusions

SNM seems to be a safe and effective treatment for LUTS in MS patients. Further and larger studies as well as randomized controlled trials are needed to confirm its clinical role in patients with MS.

     

骶神经刺激/调节在下尿路功能障碍的应用

慢性排尿功能障碍临床十分常见,主要包括急迫性尿失禁、尿频尿急综合征、慢性尿潴留和慢性盆腔疼痛综合征.目前临床中,药物和其他保守治疗方法效果不确切,外科手术因创伤大,患者不易接受,因此此类排尿障碍成为当前泌尿外科临床实践的难题之一.20世纪90年代以来,排尿反射的神经调节概念越来越被人们重视,功能性神经电刺激治疗慢性排尿功能障碍得到应用.近年来出现并不断应用于临床的骶神经刺激(sacral nerve stimulation,SNS)和骶神经调节(sacral neuromodulation)为治疗排尿功能障碍患者提供了一种新途径.本文就有关骶神经调控技术(Interstim)的原理、适应证、临床操作技术及相关进展作一简介.     

European experience with bilateral sacral neuromodulation in patients with chronic lower urinary tract dysfunction

Although there is experimental and clinical evidence that bilateral stimulation of the sacral nerves could lead to summation effects, no significant differences in unilateral versus bilateral neuromodulation could be demonstrated in a comparative trial. In some individuals, however, only bilateral stimulation relieved symptoms. Therefore, if a unilateral percutaneous nerve evaluation test fails, a bilateral test should be considered. Further clinical research with long-term follow-up will allow the identification of which patients could benefit from bilateral stimulation with greater specificity and ameliorate further the long-term results achieved with unilateral SNS.     

Sacral neuromodulation for the treatment of bladder dysfunction

S3 nerve root neuromodulation is becoming an accepted therapy for individuals afflicted with lower urinary tract symptoms, such as idiopathic urinary urge incontinence, frequency, urgency, and urinary retention, who fail current standard therapies. This patient population is difficult to treat, and this therapy offers an option that can restore quality of life to these individuals. While the precise pathophysiologic mechanisms underlying these voiding symptoms is unknown based on the physiology of bladder function, it is logical to conclude that they relate to some aberration of the neuromuscular apparatus of the bladder and/or its outlet (the urethra). These pathophysiologic defects are not overtly manifested outside the lower urinary tract because these patients routinely do not have any apparent neurologic deficits. The fact that S3 neuromodulation can clinically improve these lower urinary tract symptoms would support the notion that the neural regulation of the bladder is somehow altered in these patients. This paper presents a review of the current knowledge regarding sacral neuromodulation in treatment of non-neurogenic voiding dysfunction.     

Sacral nerve root stimulation for lower urinary tract dysfunction: overcoming the problem of lead migration

OBJECTIVE: To evaluate lead migration for two different test electrodes and the response to trial stimulation of the S3 nerve root during the selection of patients for a sacral neuromodulation implant to manage lower urinary tract dysfunction. PATIENTS AND METHODS: Twelve women (mean age 49 years, range 23-79; seven with detrusor instability and five with sensory urgency) undergoing peripheral nerve evaluation for refractory lower urinary tract symptoms were recruited. Urodynamics and a urinary diary were completed before and during test stimulation. Two electrodes (the original 041830-002 and new 3057 models, Medtronics Inc, USA) were inserted under local anaesthesia into the S3 nerve roots bilaterally. The location was determined by the functional response to stimulation. Stimulation was applied for one week using the new lead; a positive response was defined as a subjective improvement (> 50%) in urinary symptoms. Lateral sacral X-rays were taken after placement and before removing the lead. The distance from the lead tip to the ventral aspect of the S3 sacral foramen was measured by two assessors. RESULTS: Ten of the women had a positive response; the mean (range) migration of the new lead (on X-ray) was 4 (2-11) mm, and of the old lead was 12 (10-45) mm (P = 0.02). CONCLUSION: The response rate to trial stimulation was greater than in previous studies, possibly reflecting reduced migration of the new lead. The new electrode may reduce the number of test failures caused by lead migration rather than no response.     

Pathophysiology of lower urinary tract dysfunction

Lower urinary tract dysfunction can be considered in terms of two broad categories: problems caused by abnormalities of the filling and storage phase and problems related to the voiding phase. The author prefaces this discussion with a review of normal anatomy and physiology.     

Sacral neuromodulation for urinary retention after pelvic plexus injury

Injury to the pelvic plexus with resultant urinary retention is a known complication of colectomy. We describe a case of urinary retention after colectomy successfully treated with the insertion of a pelvic neuromodulator.     

Current opinion on the working mechanisms of neuromodulation in the treatment of lower urinary tract dysfunction

PURPOSE OF REVIEW: Neuromodulation is a successful treatment for patients with refractory lower urinary tract dysfunction. In the recent years, more applications of various types and ways have been developed and put into clinical practice. It is important, therefore, for urologists to know the existing theories on the working mechanisms that explain the effect. Although much research has been devoted to this subject for the past 35 years, the working mechanism is still unknown. This review presents an overview of the different theories and research into the physiological background of neuromodulation during the past 3 decades with emphasis on recent developments. RECENT FINDINGS: Specific receptors in the spinal cord have been identified, which are involved in the working mechanism of neuromodulation. The maximal effect of neuromodulation is not directly reached, indicating that neuromodulation induces learning changes (i.e. neural plasticity). The carry-over effect could be caused by negative modulation of excitatory synapses in the central micturition reflex pathway. SUMMARY: Neuromodulation in the treatment of stress incontinence probably induces physiological changes in the sphincter muscles and pelvic floor. In the treatment of overactive bladder syndrome, nonobstructive voiding dysfunction and chronic pelvic pain, the mechanism of action seems to be more complicated. Most likely, it is a combination of the different suggested modes of action, involving the neuroaxis at different levels.     

Sacral neuromodulation for urinary retention in a kidney-transplant patient

Bladder outlet obstruction can negatively affect renal function in the kidney transplant population. Functional obstruction represents a clinical challenge as conventional treatments are either ineffective or not recommended. Sacral neuromodulation was successfully used in functional voiding dysfunction in a kidney transplant patient. This is the first case to be reported in the literature.     

Applications of neuromodulation of the lower urinary tract in female urology

Neuromodulation is becoming part of clinical armamentarium for treatment of a variety of lower urinary tract conditions in female urology. Its increased usage stems from need of patients who have exhausted all other therapeutic options for their complex and poorly understood lower urinary tract disorders. Currently neuromodulation may consist of the use of sacral nerve stimulation (SNS) and injectable therapies. Herein, we will discuss the background and development of SNS, its current indications, methods of patient selection and will review the results of the recent published literature on SNS. In addition, we will discuss some of the newer developments in SNS such as Bion device and the future direction in integration of SNS in female urology.