Sacral nerve stimulation for neuromodulation of the lower urinary tract

[Functional-neurosurgical treatment options for functional pelvic floor disorders : Value of sacral neuromodulation]

BACKGROUND

Sacral neuromodulation is an established minimally invasive therapy indicated for the treatment of functional pelvic floor disorders. While it received its original US Food and Drug Administration (FDA) approval for the treatment of overactive bladder symptoms, it is now regarded as a therapeutic option to treat both urinary/fecal incontinence and retention. In addition, it has proven to be a valuable tool in the treatment of chronic pelvic pain, and preliminary results indicate a potential to elicit improvements in sexual functioning.

OBJECTIVE

This article serves to provide a summary of the therapy and its applications.

METHOD

Selective literature review.

RESULTS

Sacral neuromodulation implants allow for the controlled shifting of the autonomic control of bladder and rectum towards an inhibition or facilitation of voiding, dependent on the patient's needs and under the patient's control. At the same time and depending on the applied stimulation, the implants can interfere with the nerve's conduction of pain signals. This makes them a therapeutic option for pelvic pain that fails to respond to conventional treatment. Finally, there have been first reports suggesting improvements in sexual dysfunction under sacral neuromodulation, thus, potentially opening up a new line of therapy for those disorders.

DISCUSSION

Sacral neuromodulation is a flexible and efficient form of therapy for functional disorders of the pelvic floor. Specifically, the same intervention can treat seemingly contradictory disorders such as urinary/fecal incontinence and retention as well as chronic pain.

The Effect of Sacral Neuromodulation in Ambulatory Spina Bifida Patients with Neurogenic Bladder and Bowel Dysfunction

OBJECTIVE

To assess the effect of sacral neuromodulation (SNM) in ambulatory spina bifida patients with neurogenic bladder and bowel dysfunction.

MATERIALS AND METHODS

We retrospectively reviewed the records of 29 ambulatory spina bifida patients with neurogenic bladder and bowel dysfunction who underwent SNM testing from July 2012 to January 2020. Clinical data and video-urodynamic parameters were collected and compared using the t-test and the chi-square test. The potential risk factors were considered by logistic regression analysis. P < .05 was considered significant.

RESULTS

In the test phase, 21 patients (72.4%) achieved successful improvement of at least 1 symptom. The success rate for chronic urinary retention (26.09%) was significantly lower (P <.05) than that for urgency-frequency syndrome (58.82%) and urinary incontinence (56.25%). The mean neurogenic bowel dysfunction score decreased from 13.3±6.29 to 6.9±5.09 (P <.0001). The urodynamic evaluation showed a significant improvement in the mean maximum cystometric capacity, compliance, and maximum detrusor pressure (P <.05). Implantation was performed in 16 cases (55.17%). The analysis of the risk factors showed that chronic urinary retention was a statistically significant variable (P <.05). No complications were reported in the test phase. The average follow-up time was 41.19±33.06 months. Two patients changed to intermittent catheterization, and 2 patients changed to augmentation cystoplasty.

CONCLUSION

SNM is effective for neurogenic bladder and bowel dysfunction in patients with ambulatory spina bifida, especially in those without chronic urinary retention. And SNM can also significantly improve the urodynamic parameters of these patients during the storage period.

Long-term Outcomes of Sacral Nerve Stimulation in Pelvic Floor Dysfunctions

Purpose

The aim of this study was to analyze the long-term outcomes of sacral nerve stimulation (SNS) in both idiopathic and neurogenic pelvic floor disorders in patients treated at a referral center.

Methods

This retrospective observational study analyzed the records of 106 patients tested at our department from December 1999 to January 2017. The efficacy variables evaluated were the Global Response Assessment (range, 0%–100%) and, according to the clinical indication, other specific variables such International Consultation on Incontinence QuestionnaireShort Form, number of catheterizations or pads/day, and the numerical pain scale. The safety variables analyzed were complications (pain, migration, infection), reinterventions and explants. Patients’ quality of life (QoL) and satisfaction with the procedure were evaluated through telephone interviews.

Results

The clinical indications were overactive bladder (OAB) (n=36), urinary retention (UR) (n=37), bladder pain syndrome/interstitial cystitis (BPS/IC) (n=19), fecal incontinence (FI) (n=8), and double incontinence (DI) (n=6). The implant rates according to the clinical indication were as follows: OAB, 55.6%; UR, 56.8%; BPS/IC, 63.15%; FI, 87.5%; and DI, 66.7%. Clinical and/or statistically significant improvements in all efficacy variables were observed. Loss of therapeutic effect at 75 months of follow-up was observed in 34% of patients. Device-related pain appeared in 25 patients (39%); in 20 patients, it was resolved by reprogramming and 5 patients required device removal. An overall improvement in QoL and high levels of satisfaction with the procedure were observed. More than 90% of patients would recommend SNS to a friend or relative.

Conclusions

SNS is a minimally invasive procedure that offers a real alternative to patients with refractory pelvic floor dysfunction. Its safety profile is very favorable and it provides a long-lasting improvement in symptoms and QoL.

A Cadaveric Study on the Efficacy of Surface Marking and Bony Landmarks Used in Sacral Neuromodulation

Background

Anatomical landmarks and surface markings have long been used in out-patient contexts for conducting percutaneous nerve evaluation procedures, but studies testing the reliability of these anatomical landmarks are scant. There have been reports where the procedure has failed. Could it be possible that the anatomical landmarks that are used are not reliable enough? To answer this question, we used this study to understand the reliability of these anatomical landmarks.

Methods

Twenty cadavers, 10 males and 10 females, were dissected in the sacral region; the landmarks were tested, and the angulation and curve made by the sacral 3 (S3) nerve were also studied.

Results

Sacral 3 was identified mainly at the four o’clock position on the right and at the eight o’clock position on the left side. The Sacral 3 foramen was found at a mean distance of 9.17 ± 0.23 cm from the tip of the coccyx. The mean distance of the lateral margin of S3 from the median sacral ridge was found to be 2.16 ± 0.07 cm.

Conclusion 

The landmark of 9 cm from the coccyx tip is a valid landmark for sacral neuromodulation (SNM) procedures. The tip of the lead should follow the curve of the nerve as close as possible at the four and eight o’clock positions on the right and left side, respectively. However, the length of the coccyx differs from person to person. The proximity of the adjacent foramina to each other and the variations in the emerging of the nerve are a few factors to be considered while performing SNM procedures. Further study with a larger sample is required in order to investigate the course of the nerve, and its relationship to response to SNM.

Managing overactive bladder

Overactive bladder (OAB) is a common and distressing condition which is known to increase with age and has a significant effect on quality of life. Whilst OAB is a symptomatic diagnosis, many patients will require basic investigations prior to initiating the appropriate management. This article will review the initial clinical assessment and management of women complaining of OAB including conservative measures and drug therapy, and will also focus on the role of estrogen. In addition, the management of refractory OAB will also be discussed including more invasive strategies such as neuromodulation, Botulinum Toxin, and reconstructive surgery.

A randomized, controlled trial of transcutaneous tibial nerve stimulation to treat overactive bladder and neurogenic bladder patients

INTRODUCTION

We aimed to determine if transcutaneous tibial nerve stimulation (TTNS) is effective at treating overactive bladder (OAB) symptoms among neurogenic and non-neurogenic patients.

METHODS

We conducted a randomized, double-blind, sham-controlled study. Adult patients were recruited from one of two groups: 1) women with OAB; and 2) patients with neurogenic disease and bladder symptoms. The intervention was stimulation of the posterior tibial nerve, for 30 minutes, three times per week for 12 weeks at home using transcutaneous patch electrodes. The primary outcome was improvement of the patient perception of bladder condition (PPBC). We used ANCOVA (with adjustment for baseline values) and followed the intention-to-treat principle; we reported marginal means (MM) and a p<0.05 was considered significant.

RESULTS

We recruited 50 patients (OAB n=20, neurogenic bladder n=30); 24 were allocated to the sham group and 26 to the active TTNS group. Baseline characteristics in both groups were similar. At the end of the study, there was no significant difference in the PPBC between sham or active groups: 13% (3/24) of sham patients and 15% (4/26) of active TTNS patients were responders (p=0.77), and the MM of the end-of-study PPBC score was 3.3 (95% confidence interval [CI] 2.8-3.7) vs. 2.9 (95% CI 2.5-3.4), respectively (p=0.30). Similarly, there were no significant differences in secondary outcomes (24-hour pad weight, voiding diary parameters, or condition-specific patient-reported outcomes). The results were similar within the OAB and neurogenic bladder subgroups.

CONCLUSIONS

TTNS does not appear to be effective for treating urinary symptoms of people with OAB or neurogenic bladder dysfunction.

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.

Development of a Remote-Controlled Implantable Rat Sacral Nerve Stimulation System

OBJECTIVES

Sacral nerve stimulation (SNS) is a surgical treatment of urinary and fecal incontinence. Despite its clinical efficacy, the mechanisms of action of SNS are still poorly known. This may be related to the use of acute stimulation models. Up to date, no rodent model of chronic SNS implants has been developed. Therefore, the aim of this study was to create a fully implantable and remotely controllable stimulating device to establish an animal model of chronic SNS.

MATERIALS AND METHODS

The stimulating device consisted of an implantable pulse generator linked to a platinum electrode. The communication with the device was made through an inductive link which allowed to adjust the stimulation parameters; that is, to turn the device on and off or check the battery status remotely. Rats underwent two surgical procedures. In the first procedure, we achieved chronic sacral stimulation but the implanted electrode was not fixated. In the second procedure, the electrode was fixated in the sacral foramen using dental resin. In both cases, the correct positioning of the electrode was evaluated by computed tomography (CT) imaging and the presence of tail tremor in response to high intensity stimulation. We only tested the function of implanted electrode with fixation using micturition frequency assessment following bipolar or unipolar SNS for three days after recovery.

RESULTS

CT imaging showed that implantation of the electrode required fixation as we found that the second surgical procedure yielded a more precise placement of the implanted electrode. The correct placement of implanted electrode observed with imaging was always correlated with a successful tail tremor response in rats, therefore we pursued our next experiments with the second surgical procedure and only assessed the tail tremor response. We found that both bipolar and unipolar SNS reduced micturition frequency.

CONCLUSION

This stimulating device provides an efficient method to perform chronic SNS studies in rats.

The foreign body response and morphometric changes associated with mesh-style peripheral nerve cuffs

Nerve cuffs have been used to anchor and protect penetrating electrodes in peripheral nerves and have been used as non-penetrating electrodes for neural recording and nerve stimulation. The material of choice for such applications is silicone, an inert synthetic biomaterial which elicits a minimal chronic foreign body response (FBR). While histological studies of solid silicone cuffs are available, to the best of our knowledge a comparison to other cuff designs is not well documented. Here, we describe the FBR and morphological changes that accompany nerve cuff implantation in the rat sciatic nerve by comparing a metallic mesh with and without a parylene coating to one made of silicone. Two months after implantation, we observed that such implants, irrespective of the cuff type, were associated with a persistent inflammatory response consisting of activated macrophages attached to the implant surfaces, which extended into the endoneurial space of the encapsulated nerve. We also observed foreign body giant cells in the epineurial space that were more prevalent in the mesh cohorts. The mesh cuff groups showed significant changes in several morphometric parameters that were not seen in the silicon group including reductions in nerve fiber packing density and a greater reduction of large diameter fibers. High magnification microscopy also showed greater evidence of foamy macrophages in the endoneurial space of the mesh implanted cohorts. Although the precise mechanisms are unknown, the results showed that mesh style nerve cuffs show a greater inflammatory response and had greater reductions in morphometric changes in the underlying nerve compared to silicone in the absence of a penetrating injury.

STATEMENT OF SIGNIFICANCE

While traditional silicone cuffs have been in use for decades, the inflammatory and morphometric effects of these cuffs on the underlying nerve have not been deeply studied. Further, manipulation of the foreign body response to nerve cuffs by using various materials and/or designs has not been well reported. Therefore, we report the inflammatory response around nerve cuffs of various materials and designs, as well as report morphometric parameters of the underlying nerve. These data provide important information regarding the potential for quantitative morphometric changes associated with the use of nerve cuffs, and, importantly, suggests that these changes are associated with the degree of inflammation associated with the cuff.

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

OBJECTIVE

The objective of this study was to determine the safety and efficacy of sacral neuromodulation (SNM) in patients with idiopathic nonobstructive urinary retention.

MATERIALS AND METHODS

We retrospectively reviewed the files of patients who underwent staged neuromodulation for idiopathic nonobstructive urinary retention from 2004 to 2016 at our hospital. Patients who had a 50% improvement in symptoms after 1 week of stage 1 procedure were qualified for permanent device implantation. Patient data were assessed on efficacy and need for intermittent self-catheterization, complications, and operative revision rates.

RESULTS

Twenty-seven female patients who underwent SNM therapy were analyzed. The mean age of the patients was 32.5 ± 10.8 years. The mean duration of urinary retention was 3.2 ± 1.7 years. All patients were doing intermittent self-catheterization, but few were able to void <100 ml. Twenty-four (88.8%) of the 27 patients demonstrated a >50% improvement in symptoms and underwent permanent device placement. At a median follow-up of 5.7 ± 3.2 years, 20 (83.3%) of the 24 patients demonstrated sustained improvement rates of >50%. Seventeen (70.83%) of 24 patients could void spontaneously with a mean residual urine of 28.1 ± 24.4 ml (P < 0.001). Three (12.5%) were voiding with significant mean decreasing number of catheterizations from 5.6 ± 2.4 to 1.4 ± 2.1 (P < 0.001). Four (16.6%) had their device explanted. Ten (41.6%) of the 24 patients underwent surgical revision. Most of the adverse events were managed by device reprograming.

CONCLUSION

SNM is a highly effective and safe procedure in this subset of the female population with idiopathic refractory nonobstructive urinary retention.

The foreign body response to the Utah Slant Electrode Array in the cat sciatic nerve

As the field of neuroprosthetic research continues to grow, studies describing the foreign body reaction surrounding chronic indwelling electrodes or microelectrode arrays will be critical for assessing biocompatibility. Of particular importance is the reaction surrounding penetrating microelectrodes that are used to stimulate and record from peripheral nerves used for prosthetic control, where such studies on axially penetrating electrodes are limited. Using the Utah Slant Electrode Array and a variety of histological methods, we investigated the foreign body response to the implanted array and its surrounding silicone cuff over long indwelling periods in the cat sciatic nerve. We observed that implanted nerves were associated with increased numbers of activated macrophages at the implant site, as well as distal to the implant, at all time points examined, with the longest observation being 350 days after implantation. We found that implanted cat sciatic nerves undergo a compensatory regenerative response after the initial injury that is accompanied by shifts in nerve fiber composition toward nerve fibers of smaller diameter and evidence of axons growing around microelectrode shafts. Nerve fibers located in fascicles that were not penetrated by the array or were located more than a few hundred microns from the implant appeared normal when examined over the course of a year-long indwelling period.

Sacral neuromodulation for neurogenic bladder and bowel dysfunction with multiple symptoms secondary to spinal cord disease

STUDY DESIGN

Retrospective case series.

OBJECTIVES

The primary aim was to assess the clinical effects of sacral neuromodulation (SNM) for neurogenic bladder and/or bowel dysfunction with multiple symptoms secondary to spinal cord disease or injury.

SETTING

Beijing, China.

METHODS

Between 2011 and 2013, 23 patients with multiple bladder and/or bowel problems secondary to spinal cord disease or injury were treated with a preliminary test SNM. If at least 50% clinical improvement occurred, then the patient underwent a permanent SNM procedure. We evaluated the patients using a bladder diary, post-void residual volume measurement and the Wexner questionnaire score for constipation before the test phase, during the test phase and after the permanent SNM.

RESULTS

In the test phase, the rate of improvement in dysuria (29.4%) was significantly lower than urgency frequency (64.7%), urinary incontinence (69.2%) and constipation (75.0%). An implant was performed in 13 (56.5%) patients, including 4 patients who still used intermittent catheterization to exclude urine after permanent SNM because the symptom of dysuria could not be improved significantly and 1 patient who achieved ⩾50% improvement in lower urinary tract dysfunction but not in constipation. During follow-up (17.5±2.0 months), 1 patient (7.7%) failed and 1 patient had bilateral vesicoureteral reflux.

CONCLUSION

Chronic SNM cannot always resolve all the bladder and bowel symptoms secondary to spinal cord disease or injury, but combined with other treatments may help improve multiple symptoms.

Managing urinary incontinence: what works?

Urinary incontinence is a common condition, which, although not life-threatening, impairs the health-related quality of life of affected individuals. All women complaining of incontinence require a basic assessment and those with complex or refractory symptoms may benefit from urodynamic studies. Initial treatment includes lifestyle advice, behavioral modifications, bladder retraining and pelvic floor muscle training. For those women with persistent stress urinary incontinence following conservative therapy, surgical management might be considered. The development of the minimally invasive, retropubic, synthetic, mid-urethral sling procedures has revolutionized stress incontinence surgery and reduced the popularity of 'traditional' procedures, such as colposuspension and autologous fascial sling. In an attempt to reduce further the morbidity, transobturator and single-incision slings have been introduced. While antimuscarinic agents are the mainstay of the current medical management of urgency urinary incontinence, a recently developed selective β3-adrenergic receptor agonist (mirabegron) offers an alternative pharmacological option. Modalities such as intravesical botulinum toxin and neuromodulation (peripheral or sacral) are available to women with refractory urgency incontinence. Finally, when all other options have been explored and proven unsuccessful, inappropriate or not feasible, reconstructive surgery or catheter insertion might be considered as a last resort. The aim of this paper is to review conservative, medical and surgical management for urinary incontinence by using the best available evidence in the literature.

The management of overactive bladder refractory to medical therapy

Overactive bladder (OAB) is a clinical syndrome describing the symptom complex of urgency, with or without urgency incontinence and is usually associated with frequency and nocturia. Whilst many women may be initially managed using a clinical diagnosis alone a number will fail primary therapy and will require further investigation. Those women with refractory symptoms following initial conservative and medical therapy may benefit from alternative treatment modalities including intravesical Botulinum toxin, neuromodulation or reconstructive surgery. This review, the second of two covering the treatment of intractable OAB symptoms in women, will focus on management following the failure of medical therapy. It will principally focus on the role of Botulinum toxin, neuromodulation and reconstructive surgery.

Electrical stimulation of anal sphincter or pudendal nerve improves anal sphincter pressure

OBJECTIVE

Stimulation of the pudendal nerve or the anal sphincter could provide therapeutic options for fecal incontinence with little involvement of other organs. The goal of this project was to assess the effects of pudendal nerve and anal sphincter stimulation on bladder and anal pressures.

DESIGN

Ten virgin female Sprague Dawley rats were randomly allocated to control (n = 2), perianal stimulation (n = 4), and pudendal nerve stimulation (n = 4) groups. A monopolar electrode was hooked to the pudendal nerve or placed on the anal sphincter. Aballoon catheter was inserted into the anus to measure anal pressure, and a catheter was inserted into the bladder via the urethra to measure bladder pressure. Bladder and anal pressures were measured with different electrical stimulation parameters and different timing of electrical stimulation relative to spontaneous anal sphincter contractions.

RESULTS

Increasing stimulation current had the most dramatic effect on both anal and bladder pressures. An immediate increase in anal pressure was observed when stimulating either the anal sphincter or the pudendal nerve at stimulation values of 1 mA or 2 mA. No increase in anal pressure was observed for lower current values. Bladder pressure increased at high current during anal sphincter stimulation, but not as much as during pudendal nerve stimulation. Increased bladder pressure during anal sphincter stimulation was due to contraction of the abdominal muscles.

CONCLUSION

Electrical stimulation caused an increase in anal pressures with bladder involvement only at high current. These initial results suggest that electrical stimulation can increase anal sphincter pressure, enhancing continence control.

Impact of staged InterStim implantation on the postoperative activities of daily living and pain

OBJECTIVES

To evaluate the short-term effects of staged InterStim implantation on activities of daily living (ADL) and pain.

METHODS

This prospective study assessed women undergoing staged InterStim implantation. The Older Americans Resources and Services Program Multidimensional Functional Assessment Questionnaire asked participants about their ability to complete activities without help or what help they needed following stage I lead placement and stage II neurostimulator implantation. Narcotic use and a visual analog scale (VAS) for pain were recorded daily.

RESULTS

Thirty-eight women underwent stage I with 33 (86.8%) progressing to stage II. On stage I postoperative day (POD) 2, more women required help shopping compared with baseline (40 vs 17%, p < 0.004). The median pain score increased on Stage I POD1 (P < 0.001) and the use of narcotics increased on POD1 and 2 compared with baseline (50% vs 14%, p = 0.001). The same trends were seen following stage II.

CONCLUSIONS

Staged InterStim implantation has minimal impact on ADL, pain or narcotic requirements.

Sacral neuromodulation outcomes in patients with urge urinary incontinence and concomitant urge fecal incontinence

OBJECTIVES

: To study the efficacy and safety of sacral neuromodulation (SNM) in women with dual urge incontinence (DUI).

METHODS

: Women with simultaneous urge urinary and urge fecal incontinence (FI) were prospectively identified and tested to determine eligibility for SNM. Those who experienced at least 50% improvement in their urinary symptoms were offered a full implant. Changes in FI were not considered. Validated questionnaires were administered at baseline and during follow-up. Preimplant urodynamic data were collected. Adverse events were recorded.

RESULTS

: A total of 11 women had DUI. All had greater than 50% improvement in their urinary symptoms and underwent full implantation. Average age was 76 years. Median follow-up was 14 months. There were statistically significant improvements in validated questionnaire scores. No women were able to achieve complete simultaneous urinary and fecal continence. Six women (54%) were able to achieve at least a 50% improvement simultaneously in both their urinary and fecal symptoms. Two women (18%) only experienced a significant improvement in their urinary symptoms. One (9%) only experienced significant improvement in her FI. Two (18%) experienced no significant improvement in either their urinary or fecal symptoms. The urodynamic findings did not correlate with outcome. Two patients had transient implant pain. One implant was removed due to lack of efficacy at patient's request.

CONCLUSIONS

: SNM is a safe and effective treatment for DUI. In patients with DUI, complete continence rates may be lower than with either type of incontinence alone. DUI may be the end-organ manifestations of a common neurologic pathway-overactive stimulation or underactive inhibition.

Sacral neuromodulation therapy: a promising treatment for adolescents with refractory functional constipation

BACKGROUND

Sacral neuromodulation therapy has been successfully applied in adult patients with urinary and fecal incontinence and in adults with constipation not responding to intensive conservative treatment. No data, however, are available on sacral neuromodulation therapy as a treatment option in adolescents with refractory functional constipation.

OBJECTIVES

This study aimed to describe the short-term results of sacral neuromodulation in adolescents with chronic functional constipation refractory to intensive conservative treatment.

DESIGN

This is a retrospective review.

SETTING

This study took place at the Department of Surgery, Maastricht University Medical Centre, The Netherlands.

PATIENTS

Thirteen patients (all girls, age 10-18 years) with functional constipation according to the ROME III criteria not responding to intensive oral and rectal laxative treatment were assigned for sacral neuromodulation.

MAIN OUTCOME MEASURES

When improvement of symptoms was observed during the testing phase, a permanent stimulator was implanted. Patients were prospectively followed up to at least 6 months after implantation of the permanent stimulator by interviews, bowel diaries, and Cleveland Clinic constipation score. Improvement was defined as spontaneous defecation ≥ 2 times a week.

RESULTS

At presentation, none of the patients had spontaneous defecation or felt the urge to defecate. All patients had severe abdominal pain. Regular school absenteeism was present in 10 patients. After the testing phase, all but 2 patients had spontaneous defecation ≥ 2 times a week with a reduction in abdominal pain. After implantation, 11 (of 12) had a normal spontaneous defecation pattern of ≥ 2 times a week without medication, felt the urge to defecate, and perceived less abdominal pain without relapse of symptoms until 6 months after implantation. The average Cleveland Clinic constipation score decreased from 20.9 to 8.4. One lead revision and 2 pacemaker relocations were necessary.

LIMITATIONS

This study is limited by its small sample size, single-institution bias, and retrospective nature.

CONCLUSION

Sacral neuromodulation appears to be a promising new treatment option in adolescents with refractory functional constipation not responding to intensive conservative therapy. Larger randomized studies with long-term follow-up are required.

[Neuro-urological dysfunction of the lower urinary tract in CNS diseases: pathophysiology, epidemiology, and treatment options]

The lower urinary tract (LUT) is regulated by a complex neural network that is subject to supraspinal control. Neurological disorders, especially of the central nervous system (CNS), can rapidly lead to disruption of this control. Multiple sclerosis, Parkinson's disease, multiple system atrophy, and stroke are neurological disorders which quite frequently cause dysfunction of the LUT. With respect to the pathophysiology of bladder dysfunction in CNS diseases there are various hypotheses regarding the individual disorders: disturbances of neural communication between the frontal cortex and pontine micturition center, between the pontine micturition center and the lumbosacral parts of the spinal cord, and between the basal ganglia, thalamus, and anterior cingulate gyrus appear to play a pivotal role in the development of bladder dysfunction. The symptoms and urodynamic presentation of LUT dysfunction can vary considerably depending on the disease and disease progression and can change in the course of the disease. The incidence and prevalence of LUT dysfunctions rise with increasing progression of the underlying neurological disease.Various conservative, minimally invasive, and open surgical procedures are available to prevent harmful sequelae and to improve the quality of life of these patients. As yet, however, few data exist on most of the treatment options in cases of the above-mentioned CNS diseases. Intermittent self-catheterization and antimuscarinic medications are among the most important conservative treatment options. Injection of botulinum neurotoxin type A into the detrusor muscle and increasingly sacral or pudendal neuromodulation are among the most important minimally invasive treatment options. Surgical methods include reconstructive continent or incontinent urinary diversion.When planning therapy the patient's current needs and neurological limitations as well as possible disease progression must be taken into consideration. It is often advisable to consult with and enlist the cooperation of the attending neurologist when planning treatment.

Medium-term outcome of sacral nerve modulation for constipation

BACKGROUND

Sacral nerve modulation has been reported as a minimally invasive and effective treatment for constipation refractory to conservative treatment.

OBJECTIVE

This study aimed to evaluate the efficacy and sustainability of sacral nerve modulation for constipation in the medium term (up to 6 years) and to investigate potential predictors of treatment success.

DESIGN

We performed a retrospective review of prospectively collected data.

SETTINGS

The study was performed at 2 tertiary-care centers in Europe with expertise in pelvic floor disorders and sacral nerve modulation.

PATIENTS

Patients were eligible if they had had symptoms of constipation persisting for at least 1 year, if conservative treatment (dietary modification, laxatives and biofeedback therapy) had failed, and if predefined excluded conditions were not present.

INTERVENTION

The first phase of the treatment process was percutaneous nerve evaluation. If this was successful, patients underwent sacral nerve modulation therapy with an implanted device (tined-lead and implantable pulse generator).

MAIN OUTCOME MEASURE

Follow-up was performed at 1, 3, 6, and 12 months, and yearly thereafter. Outcome was assessed with the Wexner constipation score.

RESULTS

A total of 117 patients (13 men, 104 women) with a mean age of 45.6 (SD, 13.0) years underwent percutaneous nerve evaluation. Of these, 68 patients (58%) had successful percutaneous nerve evaluation and underwent implantation of a device. The mean Wexner score was 17.0 (SD, 3.8) at baseline and 10.2 (SD 5.3) after percutaneous nerve evaluation (p < .001); the improvement was maintained throughout the follow-up period, although the number of patients continuing with sacral nerve modulation at the latest follow-up (median, 37 months; range, 4-92) was only 61 (52% of all patients who underwent percutaneous nerve evaluation). The sole predictive factor of outcome of percutaneous nerve evaluation was age: younger patients were more likely than older patients to have a successful percutaneous nerve evaluation phase.

LIMITATIONS

The study was limited by a lack of consistent outcome measures.

CONCLUSIONS

: Despite improvement in Wexner scores, at the latest follow-up sacral nerve modulation was only being used by slightly more than 50% of the patients who started the first phase of treatment. Further studies are needed to reassess the efficacy and sustainability of sacral nerve modulation.

A modified approach to patient's selection with improved clinical outcomes in sacral nerve modulation

INTRODUCTION

Since the marketing of the percutaneous permanent tined leads (PPTL), many centres rely solely on these instead of the percutaneous nerve evaluation (PNE) as a screening tool. At our centre, we routinely perform PNE. Moreover, with our limited hospital resources, we have adopted a stricter definition of success in the patient selection process using an improvement of more than 60% as a cut-off point. This study presents our experience with sacral nerve stimulation using PPTL as an adjunct to PNE to improve the outcome of the screening method for patients suffering from refractory voiding dysfunction.

METHODS

We reviewed the charts of 106 patients who underwent a PNE between 2001 and 2008. The outcome of the procedures, the complication rates and its long-term effect were reviewed.

RESULTS

Overall, 116 PNE were performed and it was successful in 54%. Forty-five out of the 62 patients with a successful PNE underwent the stage I procedure. Of these, 93% had a successful stage I and were later implanted with the implantable pulse generator (IPG). The remaining 12 patients underwent the simultaneous implantation of the PPTL and IPG using the open procedure and it was successful in 10 of them.

CONCLUSION

The PNE is a good adjunct to the staged procedure to select the appropriate candidates for sacral nerve stimulation, especially with limited resources.

Can sacral neuromodulation improve minor incontinence symptoms in doubly incontinent patients successfully treated for major incontinence symptoms?

OBJECTIVE

To describe the effect of sacral nerve modulation (SNM) on less severe types of incontinence in patients who were successfully implanted for either urinary or fecal incontinence, and who presented with double incontinence. When conservative treatments fail, SNM is a first-line treatment for patients with urge urinary or fecal incontinence.

METHODS

All patients who received SNM between 2005 and 2010 at 5 hospitals and who still had the implant were included in our survey. All received a urinary and fecal change and quality of life questionnaire by mail to complete.

RESULTS

Of the 51 questionnaires sent out, 37 were returned, for a 72.5% response rate. The population was composed of 97.3% women, with a mean age of 56.8 years (SD 14). The main indication for SNM was urge urinary incontinence in 15 patients (40.5%) and fecal incontinence in 22 patients (59.5%). Eighteen patients (48.7%) had improvements in both urinary and fecal incontinence symptoms. The percentage increased to 53.3% (16/30) in the group of patients with urge urinary incontinence associated with fecal incontinence. Patients who reported an improvement in double incontinence symptoms complained more often of urge urinary incontinence than other patients (P=.04).

CONCLUSIONS

Of the doubly incontinent patients who were successfully implanted for a predominant type of incontinence (ie, urinary or fecal incontinence), 48.7% had an improvement in the other type of incontinence. Patients with urge urinary incontinence associated with fecal incontinence were more likely to report an improvement in double incontinence than the other patients.

Sacral neuromodulation for treating neurogenic bladder dysfunction: clinical and urodynamic study

PURPOSE

The efficacy of sacral neuromodulation for treating refractory idiopathic lower urinary tract dysfunction is now well established. Nevertheless, results of this technique in neurological patients are still controversial. The aim of this retrospective study was to assess the results of sacral neuromodulation in neurogenic bladder dysfunction.

MATERIALS AND METHODS

Between 1998 and 2008, a percutaneous nerve evaluation or a two-stage technique was performed in 62 patients (mean age 50.5 ± 14.8 years) with neurogenic lower urinary tract dysfunction. Before and during the temporary stimulation, each patient had a urodynamic evaluation and performed a bladder diary. The test was considered positive if the clinical and urodynamic improvement was over 50% and if the symptoms reappeared after turning the stimulation off.

RESULTS

Lower urinary tract dysfunction was detrusor overactivity in 34 cases and chronic urinary retention in 28 cases. A detrusor-sphincter dyssynergia (DSD) was associated in nine cases. Out of the 62 patients, 41 patients (66.1%) had more than 50% improvement on urodynamic evaluation and bladder diary and 37 were implanted. With a mean follow-up of 4.3 ± 3.7 years, results remained similar to the evaluation phase in 28 cases (75.7%), were partially altered in three cases (8.1%) and lost in six cases (16.2%). In these six cases, neuromodulation failed on average 12.0 ± 12.4 months after implantation.

CONCLUSION

Sacral neuromodulation seems to constitute a serious therapeutic option for patients with neurogenic lower urinary tract dysfunction. However, its results depend on the type of the underlying neurologic disease and in particular, whether it may progress or not.

How sacral nerve stimulation works in patients with faecal incontinence

AIM

Sacral nerve stimulation (SNS) reduces incontinence episodes and improves the quality of life of patients treated for faecal incontinence. However, the exact mechanism of action of this technique remains unclear. The present article reviews the pertinent neuroanatomy and neurophysiology related to SNS and provides explanations for potential mechanisms of action.

METHOD

A systematic review of the literature was performed for studies of the potential mechanisms of action of SNS, using MEDLINE, PubMed, Embase and the Cochrane Library. Articles dealing with the technique, adverse events and economic evaluations of SNS, as well as literature reviews, were excluded, except for reviews dealing with the mechanisms of action of SNS. The following inclusion criteria were used to select articles: (i) articles in English, (ii) randomized, double-blinded, sham-controlled studies, and (iii) cohort studies. Case-control studies or retrospective studies were cited only when randomized or cohort studies could not be found.

RESULTS

We propose three hypotheses to explain the mechanism of action of SNS: (i) a somato-visceral reflex, (ii) a modulation of the perception of afferent information, and (iii) an increase in external anal sphincter activity.

CONCLUSION

The mechanism of action of SNS in patients with faecal incontinence almost certainly depends on the modulation of spinal and/or supraspinal afferent inputs. Further research on humans and animals will be required to gain a better understanding of the mechanisms of action of SNS.

The role of sacral neuromodulation in double incontinence

AIM

Urinary and faecal incontinence are common conditions that are frequently associated. When conservative treatments fail, sacral nerve modulation (SNM) is considered to be a first-line treatment for patients with urge urinary incontinence and for patients with faecal incontinence. This article aims to determine the effect of SNM on the treatment of double incontinence (i.e. urinary and faecal incontinence).

METHOD

We searched for relevant articles in MEDLINE, PubMed and Embase, and for reviews in the Cochrane database. Articles were restricted to the English language.

RESULTS

Only a few studies have studied the efficacy of SNM for double incontinence and in a limited number of patients. Between 30% and 100% of patients with double incontinence experience improvement in urinary and faecal incontinence at medium-term follow up.

CONCLUSION

Further prospective trials are needed to determine which patients with combined problems will benefit from SNM at a long-term follow up.

Status of sacral neuromodulation for refractory constipation

AIM

This review article aims to provide a brief update on the current data on and position of sacral neuromodulation (SNM) in the specialized management of refractory idiopathic constipation.

METHOD

Published evidence from PubMed and our own unpublished data on SNM treatment for refractory idiopathic constipation were used for this evaluation.

RESULTS

Seven studies were found in PubMed that covered this topic. The main focus was on the most recently published multicentre nonrandomized European trial. Summary data from our unpublished study on constipation in children are also included.

CONCLUSIONS

The use of SNM in the treatment of idiopathic constipation is still in its early phase and while the available efficacy and safety data are limited, they show promising results. As there are few alternatives for this difficult patient group, it is worth offering a percutaneous nerve evaluation (PNE) test, which is known to be a good predictor of postimplant treatment success.

Neuromodulation for constipation: sacral and transcutaneous stimulation

Constipation is a frequently occurring digestive ailment that is usually treated conservatively. Neuromodulation is altering function of an organ by altering neural activity. This paper reviews methods of neuromodulation used to treat constipation. This includes direct stimulation of sacral nerves and stimulation across the skin. Direct stimulation of sacral nerves is the most well developed method and is presented in detail. It is generally accepted that the mechanism of action is modulation rather than stimulation so it is called sacral neuromodulation (SNM). SNM involves percutaneous placement of an electrode in the third sacral foramen and implanting a stimulating device under the skin in the buttocks. SNM is founded on the physiological principle that activity in one neural pathway modulates pre-existing activity in another through synaptic interaction. The mechanism of action in constipation may be neuromodulation of the extrinsic neural control of the large bowel or modulation of reflexes inhibiting large bowel function. Limited evidence is available to assess the outcome of SNM in constipation. Results in the medium term seem promising for selected patients with idiopathic slow and normal transit constipation not responding to optimal conservative treatment. Adverse events include electrode migration and infection. The availability of a testing phase provides a predictor of treatment outcome. In addition, transcutaneous stimulation using sticky pad electrodes over the lumbosacral region or acupuncture points has been reported to improve constipation symptoms. In general, the level of evidence is low and further studies are needed.

Long-term outcome and surgical interventions after sacral neuromodulation implant for lower urinary tract symptoms: 14-year experience at 1 center

PURPOSE

Few reports address the reoperation rate after sacral neuromodulation implants. We report our long-term results and reoperations during our 14-year experience with sacral neuromodulation at our center.

MATERIALS AND METHODS

We retrospectively reviewed the patient database at our center to assess the long-term outcome, incidence and cause of surgical re-intervention after InterStim® sacral neuromodulation implantation for lower urinary tract dysfunction between 1994 and 2008.

RESULTS

A total of 96 sacral neuromodulation devices were implanted in 88 women and 8 men. Indications for implantation were bladder pain syndrome in 47.9% of cases, urgency urinary incontinence in 35.4% and idiopathic urinary retention in 16.7%. The explantation rate was 20.8% and median time to removal was 18.5 months. Reasons for explantation in all subgroups were poor result in 12 patients, painful stimulation in 6 and radiation of stimulation to the leg in 2. Median long-term followup was 50.7 months. The long-term success rate was 87.5%, 84.8% and 73% in patients with idiopathic urinary retention, urgency urinary incontinence and bladder pain syndrome, respectively. Overall 39% of patients needed revision of the sacral neuromodulation implant. The main reason for revision was loss of stimulation in 58.5% of cases. The revision rate decreased with the introduction of the tined lead technique from 50% using lead Model 3092 to 31% using lead Model 3893 (Medtronic, Minneapolis, Minnesota). The battery was changed in 8 patients. Mean battery life was 101.8 months.

CONCLUSIONS

Sacral neuromodulation is a minimally invasive procedure with a good long-term outcome. The reoperation rate has improved with advances in surgical technique and equipment.

Selection of ideal candidates for neuromodulation in refractory overactive bladder

Sacral neuromodulation is a minimally invasive, reversible treatment option that has been approved by the US Food and Drug Administration for patients with urgency/frequency and urge incontinence. While long-term success rates are high, the high treatment cost and the need for operative revision or explantation in cases of failure make the selection of ideal candidates particularly important. Because predictive factors for success and the exact mechanism of action are not known, physicians must rely on a preimplantation test procedure, either in the office or in the operating room, to select patients for implantation of a pulse generator. In this paper, we review the recent literature on performing a test procedure with both temporary and permanent leads and the selection of optimal candidates for sacral neuromodulation therapy.

The effect of sacral nerve stimulation on uterine activity: a pilot study

INTRODUCTION

Sacral nerve stimulation (SNS) is a treatment for consecutive therapy resistant faecal incontinence or constipation. Little is known about the effects of SNS on uterocervical function. Therefore, it is advised to turn off the stimulator during pregnancy or to wait with permanent implantation of the stimulator until family completion. Diagnostic ultrasound provides an, non-invasive, opportunity to study various aspects of uterine activity. The purpose of this pilot study was to assess the influence of SNS on endometrial waves of the nonpregnant uterus by ultrasound recordings.

METHOD

Six patients with an implanted SNS were included. Ultrasound recordings were performed with the stimulator turned off and in three stimulation frequencies. Uterine activity is described as wave frequency and wave direction.

RESULTS

All three premenopausal patients showed endometrial activity with the stimulator turned off. This activity was maintained with the stimulator turned on in two patients, but disappeared in one patient. All three postmenopausal patients had no endometrial activity with the stimulator turned off. In one patient there was activity with the stimulator turned on at a frequency of 21 Hz.

CONCLUSION

We have shown some effect of SNS on uterine activity. In premenopausal women we discovered that SNS seems to exhibit no effect or an inhibitory effect rather than an excitatory effect on uterine activity. Based on the preliminary results of this study, we can not recommend any guidelines for SNS usage during conception and pregnancy. A larger study in premenopausal women with SNS is needed to investigate the significance of these changes.

[The sacral neuromodulation in double incontinence treatment: a review]

Urinary and fecal incontinence are common conditions which are frequently associated and defining double incontinence. When conservative treatments fail, sacral nerve modulation (SNM) is considered to be a first-line treatment for patients with urge urinary incontinence and for patients with fecal incontinence. The present article aims to determine the effect of SNM on the treatment of double incontinence. A medline search for clinical studies with SNM and double incontinence was carried out, extracted data were reviewed and analysed. The results of SNM in patients with double incontinence has been reported in seven studies (120 patients). The percentage of patients suffering from double incontinence improved on the urinary and fecal incontinence varied between 32% to 75%. This review reports the effectiveness of the SNM on the urinary and fecal incontinence in this population of double incontinence patients. Its main advantage would be to treat two incontinence by a single treatment. The search of predictive factors of success must be given.

Influence of naloxone on inhibitory pudendal-to-bladder reflex in cats

To determine the involvement of opioid receptors in the inhibitory pudendal-to-bladder reflex, the effect of naloxone (0.01-1 mg/kg, i.v.), an opioid receptor antagonist, on the inhibition of bladder activity evoked by pudendal nerve stimulation was investigated in alpha-chloralose anesthetized cats. The inhibition of reflex isovolumetric bladder contractions induced by pudendal nerve stimulation (5-10 Hz) at intensity threshold (T) for producing complete inhibition was significantly suppressed by naloxone at a high dose (0.3 mg/kg). However, the inhibition elicited at higher intensities (1.5-3 T) was not changed. Naloxone (1 mg/kg) did not alter the frequency dependence of the inhibitory effect of pudendal stimulation. During cystometrograms (CMGs) pudendal nerve stimulation significantly increased bladder capacity to 155.1+/-24.5% and 163.4+/-10% of the control at stimulation intensities of 1 T and 1.5-3 T, respectively. After administration of naloxone (1 mg/kg), the bladder capacity during pudendal nerve stimulation at inhibition threshold (1 T) was not significantly different from control, but it was significantly increased at higher intensities (1.5-3 T). Naloxone alone markedly reduced bladder capacity to 43+/-11.1% of the control, and pudendal stimulation completely reversed this facilitatory effect. This study revealed that activation of opioid receptors contributes to or facilitates the inhibitory pudendal-to-bladder reflex. The reduction in bladder capacity after naloxone treatment also indicates that endogenous opioid peptides mediate a tonic inhibition of micturition. Understanding the neurotransmitter mechanisms involved in the inhibitory pudendal-to-bladder reflex could promote the development of new treatments for bladder overactivity and incontinence.

Percutaneous tibial nerve stimulation for the treatment of urge fecal incontinence

PURPOSE

Percutaneous tibial nerve stimulation has been shown to be an effective treatment in patients with urinary disorders, but its benefit in fecal incontinence is uncertain. This study aimed to assess the efficacy of percutaneous tibial nerve stimulation in the treatment of urge fecal incontinence.

METHODS

This prospective study, conducted over a 14-month period, assessed 31 patients with urge fecal incontinence treated with percutaneous tibial nerve stimulation. The outcomes measured were: 1) reduction in fecal incontinence episodes, 2) improvement in Cleveland Clinic incontinence scores, and 3) improvement in ability to defer defecation. All analysis was performed on an intention-to-treat basis.

RESULTS

The median follow-up was 9 months (range, 3-14). Twenty-one (68%) patients improved following percutaneous tibial nerve stimulation and remain satisfied with the clinical response. Median fecal incontinence episodes per week declined from 4 (range, 0-30) to 0 (range, 0-27) (P < .0001). Median Cleveland Clinic incontinence scores declined from 13 (range, 5-20) to 7 (range, 0-20) (P < .0001). Ability to defer defecation was improved significantly (P < .0001). No morbidity was encountered for any patient.

CONCLUSION

This preliminary study demonstrates that percutaneous tibial nerve stimulation is an effective and very well tolerated treatment for patients with urge fecal incontinence with particular improvement in reducing fecal urgency.