Unilateral versus bilateral sacral neuromodulation in patients with chronic voiding dysfunction

PURPOSE: Bilateral sacral nerve neuromodulation has been proposed as a more effective treatment for chronic voiding dysfunction. However no comparison with the unilateral approach has been performed. We investigated the possible advantage of bilateral sacral neuromodulation. MATERIALS AND METHODS: In a prospective randomized crossover trial we investigated 33 patients who underwent bilateral implantation of a temporary test lead. Unilateral and bilateral test stimulation was continued for 4 to 6 days in all patients. Patients were randomly assigned to start with bilateral or unilateral stimulation. Between the stimulation episodes a 2-day washout interval was scheduled. Voiding diaries were completed at baseline and during the entire stimulation period. Sacral x-rays were taken to confirm lead positioning or possible migration after implantation and at the end of the test stimulation period. After 10 days the temporary leads were removed and voiding diaries were analyzed. RESULTS: After stimulation sacral x-ray revealed test lead migration in 8 patients, leaving 12 patients with urge incontinence and 13 with voiding difficulty and urinary retention available for review. A statistically significant improvement in voiding parameters was seen during the test stimulation period. However no statistically significant improvement was seen due to bilateral stimulation compared to unilateral stimulation. Two patients with urinary retention only started voiding to completion during bilateral stimulation. CONCLUSIONS: Bilateral is in general not superior to unilateral sacral neuromodulation. However, in some individuals bilateral stimulation may be more effective in relieving symptoms. Therefore, if unilateral percutaneous nerve evaluation fails, a bilateral test should be considered.     

Sacral nerve stimulation in the elderly

Sacral neuromodulation has become a widely accepted form of therapy in the overall spectrum of treatment options for urinary urgency and frequency, urge urinary incontinence, and some forms of nonobstructive urinary retention. Voiding dysfunction is very common in geriatric patients, and urgency and urge urinary incontinence are among the most prevalent forms of urinary problems in this population. Despite the fact that many different treatment options are available for these conditions, successful treatment of voiding problems in the elderly is often quite challenging. This may be exacerbated by underlying comorbidities which preclude or limit the utility of some therapies including medications. Published literature on the use and clinical outcomes of sacral nerve stimulation in older adults was reviewed and summarized. Available clinical studies examining the use of sacral neuromodulation in geriatric patients are reviewed and placed in the context of the overall treatment of voiding dysfunction in the elderly population. Sacral neuromodulation may represent a viable, minimally invasive treatment option for some older adults.     

Sacral nerve stimulation in the elderly

Sacral neuromodulation has become a widely accepted form of therapy in the overall spectrum of treatment options for urinary urgency and frequency, urge urinary incontinence, and some forms of nonobstructive urinary retention. Voiding dysfunction is very common in geriatric patients, and urgency and urge urinary incontinence are among the most prevalent forms of urinary problems in this population. Despite the fact that many different treatment options are available for these conditions, successful treatment of voiding problems in the elderly is often quite challenging. This may be exacerbated by underlying comorbidities which preclude or limit the utility of some therapies including medications. Published literature on the use and clinical outcomes of sacral nerve stimulation in older adults was reviewed and summarized. Available clinical studies examining the use of sacral neuromodulation in geriatric patients are reviewed and placed in the context of the overall treatment of voiding dysfunction in the elderly population. Sacral neuromodulation may represent a viable, minimally invasive treatment option for some older adults.     

Electrical neuromodulatory therapy in female voiding dysfunction

Female voiding dysfunction such as urge-frequency syndrome, urge incontinence and unobstructive urinary retention are often refractory to conservative management. Electrical neuromodulation with surface electrodes or with implantable systems has become a valuable addition to the therapeutic options in the last two decades. Interstitial cystitis is an emerging indication. The application of these techniques in non-neurogenic patients is reviewed. The techniques using unimplantable electrodes, anogenital electrical stimulation with plug electrodes, transcutaneous electrical nerve stimulation with surface electrodes, and posterior tibial nerve stimulation using needle electrodes are addressed. Several techniques using implantable systems are discussed, e.g. sacral nerve neuromodulation (Interstim device), pudendal nerve stimulation (Interstim and Bion device) and paraurethral neuromodulation (Miniaturo device). The long-term efficacy of neuromodulation for the established indications is more than half, but 20-50% of the patients initially tested do not respond to a test procedure. The disadvantage is the high surgical revision rate and the high cost of treatment. Technical advances will hopefully be able to address these aspects.     

Neuromodulation by implant for treating lower urinary tract symptoms and dysfunction.

OBJECTIVE: Patients with irritative micturition complaints, pelvic pain, involuntary urine loss or urinary retention are sometimes difficult to treat. The advent of direct sacral nerve stimulation offers a therapeutic alternative if conservative measures fail and surgery is considered. This paper reviews therapeutic neuromodulation by implant for treating lower urinary tract symptoms and dysfunction. METHODS: The international literature is reviewed on topics such as the physiological basis of neuromodulation, techniques of acute testing and chronic implantation, and clinical results. Future developments and ways for possible improvement are discussed. RESULTS: The mode of action of neuromodulation is probably through restoring the correct balance between excitatory and inhibitory impulses from and to the pelvic organs at a sacral and supra-sacral level. Depending on the predefined success criteria, average success rates of definitive implants vary from 50 to 70%. From the data it seems that patients with urge incontinence and urinary retention are the best candidates for neuromodulation. In the literature the lack of standardisation of selection criteria, stimulation parameters and definitions of success is striking. CONCLUSIONS: Neuromodulation by implant is a useful therapeutic alternative. It should at least be considered in patients with therapy-resistant urge incontinence and urinary retention before proceeding to surgery. Issues such as underlying physiology, methodological standardisation, technical improvements, and patient selection must be addressed in future research.     

Current and future techniques of neuromodulation for bladder dysfunction

Recent increase in the use of neuromodulation for the treatment of urinary urgency and frequency, urge incontinence, and nonobstructive urinary retention has coincided with improved knowledge of micturition physiology and concurrent technologic advances in nerve stimulation. Currently, the most common technology for bladder neuromodulation involves stimulation through the S3 foramen, or sacral neuromodulation, although other techniques of neuromodulation continue to be explored. Despite many advances in neuromodulation, the exact mechanism of action remains uncertain. Additionally, which patients will respond to neuromodulation remains unclear, and although there is a standard method for testing, this procedure is invasive and expensive. As we continue to improve patient selection criteria and better understand the mechanism of action, the efficacy and patient satisfaction should continue to increase. Currently, most patients considered for implantation with a neuromodulator are those unresponsive to other conservative treatments for bladder dysfunction.     

Sacral nerve neuromodulation in the treatment of patients with refractory motor urge incontinence: long-term results of a prospective longitudinal study

PURPOSE: Conservative treatment rarely results in a durable cure of patients with urge incontinence and bladder overactivity. Instrumental and surgical procedures often have significant side effects and less than optimal results. We developed a technique of sacral nerve neuromodulation using chronic unilateral electrical stimulation of the S3 sacral nerve to inhibit the micturition reflex to provide effective nondestructive alternative therapy for patients whose condition is refractory to conservative treatment. MATERIALS AND METHODS: Of 85 patients 45 who responded to a test with a temporary electrode underwent implantation of a permanent S3 sacral nerve electrode coupled to a pulse generator. Treatment results were evaluated by urodynamic studies and voiding/incontinence diaries documenting pad use, incontinence episodes, voiding frequency and voided volume. Partial success and cure were defined as 50% to 90% and more than 90% improvement, respectively, in pad use and/or incontinence episodes. RESULTS: Of 45 patients 18 (40%) were cured at an average followup of 47.1 months and 9 (20%) achieved partial success. Median number of pads used and median number of incontinence episodes daily had decreased from 5.4 to 1.2 (p = 0.0001) and 7.1 to 1.3 (p = 0.0001), respectively, 6 months after implantation. Subsequently these results remained almost constant for 5 years. Bladder overactivity disappeared in 19 of the 44 patients (43%). The repeat intervention rate was 37.7% and there was no permanent injury or nerve damage. CONCLUSIONS: Sacral nerve neuromodulation is safe, effective and durable in patients with urge incontinence refractory to conservative treatment.     

Alternative approaches to sacral nerve stimulation

Bladder dysfunction is a very prevalent disorder and often refractory to behavioral and pharmacologic therapies. Sacral nerve stimulation is an approved method of managing urinary urgency, frequency, urge incontinence, and urinary retention. Alternative approaches to neuromodulation are being developed. The purpose of this paper is to describe emerging approaches to neuromodulation for voiding dysfunction. A current review of alternative methods of neuromodulation is discussed. This includes stimulation of the tibial nerve via a percutaneous approach, methods of stimulating the pudendal nerve to obtain afferent stimulation through sacral roots S2–S4, chemo-neuromodulation using botulinum toxin, and anogenital stimulation. These various methods are described and the current literature reviewed. Neuromodulation is an alternative to traditional management of voiding dysfunction. A benefit of neuromodulation is that it is minimally invasive and reversible. New sites of stimulation are being developed to add to our treatment options.     

The Role of Neuromodulation in Patients with Neurogenic Overactive Bladder

To review the treatment options for patients with neurogenic overactive bladder (OAB), specifically the use of sacral neuromodulation (SNM). A search was performed on the available literature on SNM and lower urinary tract dysfunction. Based on published studies available and also on personal experience, the treatment options for neurogenic OAB are reviewed, and specifically, the role for SNM in these patients is discussed. SNM is FDA-approved for patients with urge incontinence, urgency/frequency, and non-obstructive urinary retention. It involves stimulation of the third sacral nerve with an electrode implanted in the sacral foramen and connected to a pulse generator. The procedure is minimally invasive and is effective in about 70?% of patients who have a permanent system. The original trials leading to the approval of SNM excluded patients with neurogenic disease, as it was felt that intact spinal pathways were necessary for neuromodulation to occur. However, similar success rates have been observed in patients with neurogenic OAB. Special considerations for SNM use in patients with neurogenic OAB include recognizing that it is incompatible for patients who will need MRI's due to their progressive neurologic disease. Many treatment options are available for patients with neurogenic OAB. First-line approaches remain conservative with lifestyle changes and anticholinergic medications. SNM has been used successfully in this patient population with good results, though larger randomized trials are lacking.     

Chronic sacral neuromodulation for treatment of neurogenic bladder dysfunction: long-term results with unilateral implants

Objectives. To investigate the therapeutic value of sacral neuromodulation in patients with neurogenic disorders in whom conservative treatment options were unsuccessful. Neurogenic disorders may result in various forms of lower urinary tract dysfunction.Methods. Twenty-seven patients (19 women, 8 men) aged 18 to 63 years (mean 44.9 years) were subjected to percutaneous test stimulation of the sacral spinal nerves. Their urologic symptoms consisted of bladder storage failure (n = 15) due to detrusor hyperreflexia and/or bladder hypersensitivity, failure to empty due to detrusor areflexia (n = 11), and combined bladder hypersensitivity and detrusor areflexia (n = 1). Twelve patients (11 women and 1 man) underwent chronic sacral neuromodulation with unilateral electrode implantation into one of the dorsal S3 foramina. The follow-up was 89.3 months (range 13 to 126).Results. Severe side effects were encountered in 2 patients (1 with infection and 1 with adverse sensation during stimulation) and moderate side effects in another 3 patients. In 1 patient, the implant had to be removed during the immediate postoperative period. In 3 patients, the implant was not effective. In 8 patients, the symptoms of lower urinary tract dysfunction were significantly attenuated (50% or more) for 54 months (range 11 to 96). After this period, all implants became ineffective, except one, which was still in use at the last follow-up visit.Conclusions. Unilateral chronic sacral neuromodulation using sacral foramen electrodes can be a valuable, but only temporary, treatment for neurogenic bladder dysfunction. The technique of chronic sacral neuromodulation should be refined to achieve the same and lasting results with implantation systems as achieved with preoperative test stimulation.     

Expanding indications for neuromodulation

Neuromodulation in one form or another has been studied for decades for various disease states. Although its mechanism of action remains un-explained, numerous clinical success stories suggest it is a therapy with efficacy and durability. Controlled studies have led to the approval of sacral neuromodulation for urinary urgency and frequency, urinary retention, and urinary urge incontinence. The future holds hopeful possibilities for the application of neuromodulation, namely in the areas of interstitial cystitis, in-tractable pain syndromes, fecal incontinence and constipation, spinal cord injury, and erectile dysfunction. Neuromodulators have also been used in nonurologic conditions, including chronic headaches and intractable chest pain. In adults and children, in the neurologically intact and neurologically impaired, neuromodulation has been shown to improve the quality of life of those suffering chronic disease states. Neuromodulation is changing the future of urology. Treatment of voiding dysfunction and likely other disorders, such as pelvic pain, sexual dysfunction, and bowel disorders, will no longer rely only on medications that are "OK" or destructive-reconstructive procedures that suffer from significant complications. Rather, by modulating the nerves, the urologists will treat these disorders in a minimally invasive fashion and neuromodulation will become the first-line therapy before any major surgery is undertaken.     

The role of neuromodulation in the management of urinary urge incontinence

OBJECTIVE: To examine the benefit-risk profile of neuromodulation in treating refractory urinary urge incontinence and other voiding disorders. PATIENTS AND METHODS: The outcome measures from all patients in pivotal clinical trials who had undergone sacral nerve stimulation were analysed retrospectively. RESULTS: Neuromodulation was effective in several clinical studies; the response is durable and the benefit-risk profile good. CONCLUSION: Sacral nerve stimulation is becoming the standard of care for refractory overactive bladder and retention problems. The potential benefit of neuromodulation should be included in female urology and gynaecology training programmes.     

Successful use of sacral neuromodulation after failed bladder augmentation

Sacral neuromodulation has become a standard minimally invasive therapy for refractory urinary urge/frequency and urge incontinence. Prior to the widespread use of sacral neuromodulation, augmentation cystoplasty was a standard treatment for refractory overactive bladder (OAB). The use of sacral neuromodulation following bladder augmentation has not been previously reported in the literature. We report 2 cases of successful sacral neuromodulation in patients with OAB refractory to bladder augmentation.     

Sakrale Neuromodulation in der Urologie

Sacral nerve modulation (SNM) is an innovative, minimally invasive treatment that uses chronic low-level electrical stimulation of the sacral plexus to recruit residual physiological function of urinary bladder detrusor, pelvic floor muscles, and the anorectal continence structures. Classic indications for sacral neuromodulation in urology are refractory overactive bladder symptoms (urinary urgency ± incontinence) and chronic nonobstructive urinary retention. SNM also offers a therapeutic alternative in refractory chronic pelvic pain syndrome. The exact mechanism of action is still unknown, but it is assumed that electrical stimulation of the sacral nerves leads to neuromodulation as well as clinically beneficial effects in the pelvic floor, the sphincter complex, and the distal colorectum. SNM is a multistep procedure. In a test phase of so-called percutaneous or peripheral nerve evaluation (PNE), the effect of sacral neuromodulation is evaluated over days or weeks during which a bladder diary/pain protocol is kept. The predictive value of PNE is high, while morbidity and surgical trauma are low. The screening phase provided by PNE makes this technique unique and offers an ideal instrument for patient selection. After final implantation of the neurostimulator (InterStim II), the long-term success rate is over 60–90%. At our clinic, 42 patients underwent a PNE procedure between January 2009 and June 2010. Of these, 34 patients had a >50% success rate and had been implanted with the InterStim II device (80.9%). The success rates were 83% for overactive bladder and 89% for chronic retention (mean follow-up 7.8 months). In addition to the surgical procedure, the exact indication and postoperative care are important prerequisites of successful therapy. To date, no information on the number of implanted stimulators in Germany is available. This suggests the need for establishment of a national prospective registry. It would also be appropriate that the experts from the implantation centers form a working group.     

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 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 stimulation for faecal incontinence

Faecal incontinence is a common problem. Conservative measures are effective in a significant proportion of patients. Failure of conservative management has until recently meant recourse to surgical intervention. Surgical treatment is often associated with disappointing results. Recently, sacral nerve stimulation (SNS) has been developed as a minimally invasive, effective technique for idiopathic and acquired faecal incontinence. The technique uses chronic low-level electrical stimulation of the sacral nerves, or neuromodulation, to produce a clinically beneficial effect on the distal colon and rectum, the pelvic floor and the anal sphincter complex. SNS is a 2-stage procedure: a diagnostic stage - temporary percutaneous nerve evaluation (PNE), and a therapeutic stage - permanent SNS. The predictive value of PNE is high, and the surgical trauma and morbidity of both procedures extremely low. The technique has been adapted from its original application in urinary dysfunction. It is almost impossible to produce level 1 evidence for this type of intervention; however, the results are superior to other interventions. Patient selection criteria are evolving, but there is a growing body of evidence that supports its use as first-line treatment for faecal incontinence in patients where conservative measures have failed.     

The use of sacral neuromodulation for the treatment of non-obstructive urinary retention secondary to Guillain-Barré syndrome

Guillain-Barré syndrome, an acute autoimmune polyneuropathy and demyelinating disease, is characterized by weakness, sensory loss, areflexia, pain, autonomic dysfunction, and occasionally, micturition disturbances including voiding difficulty, urinary retention, nocturnal urinary frequency, and urge incontinence. Typically, urinary dysfunction resolves simultaneously with other neurologic deficits. We report the case of a 20-year-old woman with Guillain-Barré syndrome and persistent urinary retention 18 months following initial diagnosis. This patient is the first described in the literature to undergo successful treatment with sacral neuromodulation. Immediately following neuromodulator placement, the patient voided spontaneously and has had no voiding dysfunction or postvoid residual after 5 months of follow-up.     

Detrusor overactivity does not predict outcome of sacral neuromodulation test stimulation

The aim of this study is to determine if urodynamic findings in patients with urge incontinence predicts response to sacral neuromodulation test stimulation. One hundred four patients with refractory urinary urge incontinence who had undergone sacral neuromodulation test stimulation were retrospectively reviewed. Pre- and post-test stimulation incontinence parameters and pelvic floor muscle (PFM) contraction strength was documented. Urodynamics were reviewed on all patients, and the presence or absence of detrusor overactivity (DO) was noted. Patients were then divided into two groups: responders to the test stimulation and non-responders. A positive response was considered to be a ≥50% improvement in the number of incontinent episodes per day (IE/day) and/or pad weight with test stimulation. Of the 104 patients evaluated, 64% (N = 67) responded to the test stimulation, while 36% (N = 37) were non-responders. The mean age was 59.7 and 67.0 among responders and non-responders (p = .01). There was a significant difference in the number of IE/day between non-responders and responders (p = .02). There was no relationship found between the presence or absence of DO and the likelihood for test stimulation success, patient demographics or pre test stimulation incontinence variables. Our study provides no statistically significant evidence that the presence or absence of DO on urodynamics predicts a response to sacral neuromodulation test stimulation. An important finding, however, was that patients without demonstrable DO on urodynamics may still have a positive response to sacral neuromodulation.