Improving the efficacy of sacral nerve stimulation for faecal incontinence by alteration of stimulation parameters

Electroceuticals for Neurogastroenterology and Motility Disorders

PURPOSE OF REVIEW

To provide an updated overview on use of electrostimulation in gastrointestinal motility disorders and obesity, with a focus on gastric electrical stimulation, vagal nerve stimulation and sacral nerve stimulation.

RECENT FINDINGS

Recent studies on gastric electrical stimulation for chronic vomiting showed a decrease in frequency of vomiting, but without significant improvement in quality of life. Percutaneous vagal nerve stimulation shows some promise for both symptoms of gastroparesis and IBS. Sacral nerve stimulation does not appear effective for constipation. Studies of electroceuticals for treatment of obesity have quite varied results with less clinical penetrance of the technology. Results of studies on the efficacy of electroceuticals have been variable depending on pathology but this area remains promising. Improved mechanistic understanding, technology and more controlled trials will be helpful to establish a clearer role for electrostimulation in treatment of various GI disorders.

Is sacral nerve modulation reprogramming effective after permanent implantation for faecal incontinence?

AIM

Sacral nerve modulation (SNM) is recommended as a first-line surgical therapy for patients with faecal incontinence (FI). During patient follow-up, it is recommended that stimulation settings be reprogrammed to optimize patient outcomes. The aim of the present study was to evaluate the efficacy of stimulator reprogramming in patients with an implanted SNM device to treat FI.

METHOD

The data from patients who received a permanent SNM implant in a single centre from January 2008 to December 2019 were retrospectively analysed. Symptoms that occurred after implantation, the stimulator settings of the SNM device and changes made at each follow-up visit were noted. The efficacy of reprogramming was determined by assessing patient satisfaction.

RESULTS

Of the 117 patients (male/female 4/113; mean age 59.5 ± 11.8 years) with a SNM implant for FI, 84 (72%) had at least one symptom requiring reprogramming of the stimulator, most often during the first year after implantation (p = 0.05). The most frequently reported symptoms were loss of efficacy (68.5%; p = 1 × 10^-3 ) and pain (20.5%; p = 1 × 10^-3 ). Reprogramming was effective 53% of the time when treating loss of efficacy and 76% of the time when treating pain. When the stimulation parameters were reprogrammed at least four consecutive times to correct a symptom, the reprogramming was less effective in treating the symptom (p = 0.02).

CONCLUSION

Regular follow-up of patients with SNM device implants associated with reprogramming of stimulation parameters to improve the treatment of reported symptoms would optimize the efficacy of SNM.

Reprogramming Sacral Neuromodulation for Sub-Optimal Outcomes: Evidence and Recommendations for Clinical Practice

Objectives

In some patients treated for urinary or fecal incontinence with sacral neuromodulation (SNM) persistence of symptoms, a reduction in efficacy or adverse effects of stimulation can occur. In such situations, further programming of the SNM device can help resolve problems. Infrequently hardware failure is detected. This article aims to provide practical guidance to solve sub‐optimal outcomes (troubleshooting) occurring in the course of SNM therapy.

Materials and Methods

A systematic literature review was performed. Collective clinical experience from an expert multidisciplinary group was used to form opinion where evidence was lacking.

Results

Circumstances in which reprogramming is required are described. Actions to undertake include changes of electrode configuration, stimulation amplitude, pulse frequency, and pulse width. Guidance in case of loss of efficacy and adverse effects of stimulation, developed by a group of European experts, is presented. In addition, various hardware failure scenarios and their management are described.

Conclusions

Reprogramming aims to further improve patient symptoms or ensure a comfortable delivery of the therapy. Initial changes of electrode configuration and adjustment of stimulation parameters can be performed at home to avoid unnecessary hospital visits. A logical and stepwise approach to reprogramming can improve the outcome of therapy and restore patient satisfaction.

The role of pulse width manipulation compared to program changes alone for unsatisfactory sacral neuromodulation therapy: A retrospective matched-cohort analysis

AIM

Pulse width (PW) influences neuromodulation by its impact on nerve fiber recruitment. A paucity of data regarding the manipulation of PW in sacral neuromodulation (SNM) exists. This study describes the clinical features and outcomes of PW manipulation for unsatisfactory SNM therapy.

METHODS

A retrospective, single-institution review was performed of reprogrammed SNM patients between 2010 and 2019. Two cohorts were created: those with PW changes ± program changes and age-matched controls with program changes alone. Patients lacking follow-up and non-InterStim II models were excluded.

RESULTS

Out of 710 SNM interrogations, 147 (20.7%) had PW changes and 80 met inclusion criteria. Most PW changes were shortened (61/80, 76.3%). Clinical features did not differ between cohorts except by indication for reprogramming. The most common indication for PW change was painful stimulation (34/80, 43%), whereas in controls it was suboptimal efficacy (76/80, 95%). Clinical success was stratified by indication. There was a higher improvement in efficacy in the PW cohort (61%, 17/28 vs. 36%, 27/76, p = .02). PW manipulation successfully relieved painful stimulation in 50% (17/34 vs. 0/3, p = .23), which was more likely with a shortened compared to extended PW (14/15, 93.3% vs. 0/6, 0%, p < .01). PW resulted in improvement in localization of the stimulus in 94% (17/18 vs. 0/1, p = .10). The subsequent lead revision or explant was significantly higher in the PW cohort (43% vs. 25%, p = .03).

CONCLUSION

PW manipulation may aid the salvage of unsatisfactory SNM therapy. These findings represent an initial assessment of the role of PW in SNM, particularly regarding the efficacy and painful stimuli. The further prospective investigation is warranted.

Long-term outcome of sacral nerve stimulation for faecal incontinence

AIM

Sacral nerve stimulation (SNS) is a minimally invasive treatment for faecal incontinence (FI). We report our experience of patients who have undergone SNS for FI with a minimum of 5 years' follow-up. This is a single centre prospective observational study with the aim to assess the long-term function of SNS.

METHOD

All patients implanted with SNS were identified from our prospective database. The date of implantation, first and last clinic follow-up, surgical complications and St Mark's incontinence scores were abstracted and analysed.

RESULTS

From 1996 to 2014, 381 patients were considered for SNS. Of these, 256 patients met the study inclusion criteria. Median age at implantation was 52 years (range 18-81). The ratio of women to men was 205:51. Indications were urge FI (25%), passive FI (17.9%) and mixed FI (57%). The median of the incontinence score at baseline was 19/24 and this improved to 7/24 at the 6-month follow-up. Of the total cohort, 235 patients received a medium-term follow-up (median 110 months, range 12-270) with a median continence score of 10/24 which was also confirmed at the telephone long-term follow-up on 185 patients (132 months, range 60-276).

CONCLUSION

This study demonstrates that SNS is an effective treatment in the long term. SNS results in an improvement of validated scores for approximately 60% of patients; however, there is a significant reduction of efficacy over time due to underlying causes.

The effect of the number of active electrode poles during tined lead placement on long-term efficacy of sacral neuromodulation in patients with faecal incontinence

AIM

There is an ongoing debate as to whether or not the efficacy of sacral neuromodulation (SNM) is optimized by maximizing the total number of active electrode poles (AEPs) during lead placement because there are more programming options. However, this is at the cost of increased operating time. The aims of this study were to establish if a higher number of AEPs improves SNM efficacy during the trial period and after permanent implantable pulse generator (IPG) placement and if there is there a correlation between number of AEPs and battery life of the first placed IPG.

METHOD

This was a single centre retrospective cohort study of new patients with faecal incontinence who underwent SNM between 2000 and 2018. Exclusion criteria were sphincter defect > 30%, rectocele/enterocele Grade 3 or higher and incomplete records.

RESULTS

In all, 288/456 (63%) patients (women 91%; mean age 58.5 ± 11.7 years) were eligible for analysis. The number of AEPs during lead placement was two (n = 42, 14.5%), three (n = 82, 28.5%) and four (n = 164, 57%). There was no association between the number of AEPs during tined lead placement and long-term efficacy. Neither the success rate of the trial phase nor the battery life after first placed IPG was influenced by the number of AEPs.

CONCLUSION

In this study, the number of AEPs does not seem to influence long-term efficacy of SNM success rate during the trial phase or the battery life of the first placed IPG. However, we also suggest that at the very least there should be two AEPs at lead placement.

A rare case of tined lead migration of InterStim device into the rectum with subsequent novel combined surgical-endoscopic removal technique

After the introduction of self-anchoring tined leads in 2002, lead migration after sacral neuromodulation (SNM) in the form of InterStim^TM (Medtronic, Minneapolis, MN) has been reduced; however, it remains a considerable complication of this otherwise low-risk procedure. As intestinal perforation through lead migration or primary incorrect positioning portrays a rarity and has been scarcely reported in the literature, no algorithm for explantation in such cases has been determined. We present a case of a young man with an SNM device implant (InterStim II^®) because of neurogenic urinary retention, who was admitted with inflammation, localized at the sacral lead insertion site. Our diagnostic algorithm revealed a tined lead electrode protruding into the rectum without concomitant abscess. We performed an interdisciplinary surgical approach combining regular incisions over the sacrum and buttocks for dissection of the lead and the implanted pulse generator, respectively, with an endoscopic transanal lead extraction. This method prevented further bacterial seeding in the surrounding tissues of the colon and, therefore, presacral abscess formation or sacral osteomyelitis. Combined surgical-endoscopic removal of the InterStim device is an effective and safe procedure that should be included in the armamentarium of urologists performing neuromodulation surgery in cases of intestinal perforation.

Stimulation Parameters for Sacral Neuromodulation on Lower Urinary Tract and Bowel Dysfunction-Related Clinical Outcome: A Systematic Review

Objective

Sacral neuromodulation (SNM) has been used to treat patients with lower urinary tract dysfunction and bowel dysfunction for many years. Success rates vary between 50% and 80%, indicating that there is much room for improvement. Altering stimulation parameters may result in improved outcome. This paper reports a systematic review of the clinical efficacy of nonconventional stimulation parameters on urinary tract and bowel dysfunction.

Materials and Methods

Three databases were used for the literature search: Ovid (Medline, Embase) and PubMed. Papers were screened by two independent reviewers, who also extracted data from these papers. Clinical papers studying SNM stimulation parameters, that is, intermittent stimulation, frequency, pulse width, and amplitude, in urinary tract and bowel dysfunction were included. Quality of included papers was assessed using standardized guidelines.

Results

Out of 5659 screened papers, 17 papers, studying various stimulation parameters, were included. Overall quality of these papers differed greatly, as some showed no risk of bias, whereas others showed high risk of bias.

Stimulation parameters included intermittent stimulation, frequency, pulse width, amplitude, and unilateral vs. bilateral stimulation. Especially high frequency SNM and either a narrow or wide pulse width seem to improve efficacy in patients with bowel dysfunction. Additionally, implementation of short cycling intervals is promising to improve quality of life for patients with urinary tract or bowel dysfunction.

Conclusion

The results of our systematic review indicate that stimulation parameters may improve efficacy of SNM in treatment of both urinary tract dysfunction and bowel dysfunction.

Programming Algorithms for Sacral Neuromodulation: Clinical Practice and Evidence-Recommendations for Day-to-Day Practice

Background

In sacral neuromodulation (SNM), stimulation programming plays a key role to achieve success of the therapy. However to date, little attention has been given to the best ways to set and optimize SNM programming during the test and chronic stimulation phases of the procedure.

Objective

Standardize and make SNM programming easier and more efficient for the several conditions for which SNM is proposed.

Methods

Systematic literature review and collective clinical experience report.

Results

The basic principles of SNM programming are described. It covers choice of electrode configuration, stimulation amplitude, pulse frequency and pulse widths, while use of cycling is also briefly discussed. Step‐by‐step practical flow charts developed by a group of 13 European experts are presented.

Conclusions

Programming of SNM therapy is not complex. There are few programming settings that seem beneficial or significantly impact patient outcomes. Only four basic electrode configurations could be identified according to four different options to define the cathode. In a majority of patients, the proposed stimulation parameters will allow a satisfactory improvement for long periods of time. A regular follow‐up is, however, necessary to assess and eventually optimize results, as well as to reassure patients.

Improved longevity and efficacy of sacral nerve stimulation by simple adjustments at follow-up

AIM

Sacral nerve stimulation (SNS) for faecal incontinence (FI) at subsensory amplitudes as low as 50% of the sensory threshold has been found to be effective at 3 months' follow-up. Furthermore, alternative pacemaker settings may improve functional outcome in patients with suboptimal treatment efficacy. In this work we aim to explore if sub-sensory stimulation as low as 50% of sensory threshold is effective at 1-year follow-up. We also aimed to investigate if 31 Hz (frequency) or 90 µs (pulse width) stimulation improved treatment efficacy in dissatisfied patients.

METHOD

All patients in whom the stimulation was effective in controlling FI (satisfied group) were encouraged to have the stimulation amplitude reduced. Those in whom the device was less effective (dissatisfied group) were offered alternative frequency settings or pulse width (31 Hz or 90 µs). Patients were follow-up after 12 months and evaluated by a visual analogue scale (VAS) for patient satisfaction, the Cleveland Clinic Continence Score (CCCS), Rockwood Faecal Incontinence Quality of Life Scale (QoL) and a bowel habit diary.

RESULTS

Two hundred and nineteen patients were contacted, with a response rate of 71% (n = 155). Those who were successfully contacted comprised 110 (71%) patients classed as satisfied and 45 (29%) as dissatisfied. Seventy-five (68%) of the satisfied patients agreed to have their stimulation amplitude reduced. At 1-year follow-up the median amplitude had reduced from 1.5 V [interquartile range (IQR) 0.85-2.0 V] to 0.75 V (IQR 0.45-1.4 V) (P-value < 0.001) representing an overall reduction of 39% (6.6-62.5%). There were no significant differences in VAS, CCCS or QoL despite subsensory stimulation at 1-year follow-up. In 28% of the dissatisfied patients alternative pacemaker settings improved VAS to satisfactory levels.

CONCLUSION

Subsensory stimulation is as effective as stimulation at or above the sensory threshold. High-frequency stimulation (31 Hz) can improve functional outcome in patients with loss of efficacy.

An intravital window to image the colon in real time

Intravital microscopy is a powerful technique to observe dynamic processes with single-cell resolution in live animals. No intravital window has been developed for imaging the colon due to its anatomic location and motility, although the colon is a key organ where the majority of microbiota reside and common diseases such as inflammatory bowel disease, functional gastrointestinal disorders, and colon cancer occur. Here we describe an intravital murine colonic window with a stabilizing ferromagnetic scaffold for chronic imaging, minimizing motion artifacts while maximizing long-term survival by preventing colonic obstruction. Using this setup, we image fluorescently-labeled stem cells, bacteria, and immune cells in live animal colons. Furthermore, we image nerve activity via calcium imaging in real time to demonstrate that electrical sacral nerve stimulation can activate colonic enteric neurons. The simple implantable apparatus enables visualization of live processes in the colon, which will open the window to a broad range of studies.

Performing intravital imaging of the colon in mouse models is challenging due to the colon’s anatomic location and motility. Here, the authors develop a murine colonic window for intravital chronic imaging that maximises long-term animal survival and minimises motion artefacts.

International Continence Society best practice statement for use of sacral neuromodulation

AIMS

Sacral neuromodulation (SNM) is an accepted therapy for a variety of conditions. However, despite over 20 years of experience, it remains a specialized procedure with a number of subtleties. Here we present the recommendations issued from the International Continence Society (ICS) SNM Consensus Panel.

METHODS

Under the auspices of the ICS, eight urologists, three colorectal surgeons and two urogynecologists, covering a wide breadth of geographic and specialty interest representation, met in January 2017 to discuss best practices for neuromodulation. Suggestions for statements were submitted in advance and specific topics were assigned to committee members, who prepared and presented supporting data to the group, at which time each topic was discussed in depth. Best practice statements were formulated based on available data. This document was then circulated to multiple external reviewers after which final edits were made and approved by the group.

RESULTS

The present recommendations, based on the most relevant data available in the literature, as well as expert opinion, address a variety of specific and at times problematic issues associated with SNM. These include the use of SNM for a variety of underlying conditions, need for pre-procedural testing, use of staged versus single-stage procedures, screening for success during the trial phase, ideal anesthesia, device implantation, post-procedural management, trouble-shooting loss of device function, and future directions for research.

CONCLUSIONS

These guidelines undoubtedly constitute a reference document, which will help urologists, gynecologists, and colorectal surgeons optimize their use of SNM for refractory urinary urgency and frequency, UUI, NOR, and FI.

Long-term outcome of intractable constipation treated by sacral neuromodulation: a comparison between children and adults

AIM

Sacral neuromodulation (SNM) is a minimally invasive therapy for functional constipation (FC) and is most often used to treat adults. Recent studies suggest that SNM may also beneficial in children. However, comparative data regarding preferred age of SNM for FC are lacking. Therefore, long-term results of SNM for FC were compared between children and adults.

METHOD

All patients treated with SNM for FC between 2004 and 2015 were evaluated. Outcomes of children (age 10-18 years) were compared with those for adults (≥ 18 years). The primary end-point was a defaecation frequency of three or more times per week, which is consistent with the ROME-III criteria. Secondary outcomes were quality of life (QoL; SF-36) and the Cleveland Clinic Constipation Score.

RESULTS

One hundred and eighty patients (45 children, 135 adults) were eligible for SNM. The mean age was 15.8 (children) and 41.4 years (adults). One hundred and twenty-six patients received permanent SNM (38 children, 88 adults). Mean follow-up was 47 months in both groups. Defaecation frequency increased in both groups after SNM compared with baseline. Defaecation frequency in adults was higher than in children. The increased defaecation frequency was maintained during the entire follow-up period in both groups. QoL of children was impaired compared with the Dutch population with regard to bodily pain, general health and vitality. Adults had worse QoL with regard to physical functioning, bodily pain, general health, vitality and social functioning compared with the Dutch population. QoL of children did not differ from adults.

CONCLUSION

Sacral neuromodulation (SNM) should be considered in children (< 18 years) with FC. However, the indication of SNM for FC remains debatable considering the limited improvements and high costs.

A double-blinded randomized multicentre study to investigate the effect of changes in stimulation parameters on sacral nerve stimulation for constipation

AIM

Sacral nerve stimulation (SNS) may be offered to patients with constipation who have failed to improve with conservative treatment. The response to SNS is variable, with a significant loss of efficacy in some patients. An increased frequency of stimulation may improve the efficacy of SNS for faecal incontinence. This study aimed to see if alteration of the pulse width or frequency improved the outcome for those with constipation.

METHOD

Eleven patients with constipation currently being treated by SNS were recruited from three centres. They were randomized to five different protocols of stimulation each applied for 5 weeks. Group 1 used standard settings (pulse width 210 μs, frequency 14 Hz); in the other four groups (Groups 2-5) the pulse width and/or frequency were halved or doubled. Patients and investigators were blinded to the group allocation.

RESULTS

The Cleveland Clinic constipation score varied significantly between the five groups. Group 1 achieved the lowest score mean (± SD) 13.4 (± 4.4) (P = 0.03). The number of digitations per defaecation was the lowest in Group 4, 90 μs and 14 Hz (P < 0.01). No other variable changed significantly. Standard settings were the most preferred by the recruited patients.

CONCLUSION

Alteration of pulse width or frequency of stimulation had no significant effect on the outcome of SNS for constipation.

Sacral nerve stimulation for faecal incontinence and constipation: a European consensus statement

AIM

In Europe during the last decade sacral nerve stimulation (SNS) or sacral neuromodulation (SNM) has been used to treat faecal incontinence (FI) and constipation. Despite this, there is little consensus on baseline investigations, patient selection and operative technique. A modified Delphi process was conducted to seek consensus on the current practice of SNS/SNM for FI and constipation.

METHOD

A systematic literature search of SNS for FI and constipation was conducted using PubMed. A set of questions derived from the search and expert opinion were answered on-line on two occasions by an international panel of specialists from Europe. A 1-day face-to-face meeting of the experts finalized the discussion.

RESULTS

Three hundred and ninety-three articles were identified from the literature search, of which 147 fulfilled the inclusion criteria. Twenty-two specialists in FI and constipation from Europe participated. Agreement was achieved on 43 (86%) of 50 domains including the set-up of service, patient selection, baseline investigations, operative technique and programming of the device. The median of agreement was 95% (35-100%).

CONCLUSION

Consensus was achieved on the majority of domains of SNS/SNM for FI and constipation. This should serve as a benchmark for safe and quality practice of SNS/SNM in Europe.

Effects of stimulation frequency and intensity in sacral neuromodulation on anorectal inputs to the somatosensory cortex in an experimental model

Introduction

Although sacral neuromodulation (SNM) is an established treatment for faecal incontinence, stimulation parameters have been derived empirically and only one frequency (14 Hz) is employed clinically. The aim of this study was to test a range of stimulation frequencies to establish an optimal frequency of SNM for maximum augmentation of anal canal cortical evoked potentials (EPs) in an animal model.

Methods

In female Wistar rats, anal canal EPs were recorded over the primary somatosensory cortex using a flexible multielectrode array, and the effect of SNM was studied. SNM was applied at 0·1–100 Hz and a frequency response curve plotted. The data were fitted to a quadratic equation.

Results

The magnitude of potentiation of anal canal EPs caused by SNM depended significantly on stimulation frequency (P &lt; 0·001). The frequency–potentiation relationship was parabolic in form, with a clear optimum at 2 Hz. The SNM must be applied for at least 3 min. The theoretical maximal potentiation predicted by the model was not found to be statistically different to actual data recorded (P = 0·514–0·814). The response depended on stimulation amplitude in an ‘all-or-nothing’ fashion. EPs were augmented when the SNM intensity was 0·5 times the motor threshold to tail twitch or greater, but values below this intensity failed to affect the EPs.

Conclusion

The effect of SNM in this animal model is governed principally by frequency, with an optimum of 2 Hz. If animal data can be translated to humans, optimization of SNM frequency may offer a clinically relevant improvement in the efficacy of SNM.

Sacral neuromodulation and peripheral nerve stimulation in patients with anal incontinence: an overview of techniques, complications and troubleshooting

Sacral neuromodulation (SNM) therapy has revolutionized the management of many forms of anal incontinence, with an expanded use and a medium-term efficacy of 75% overall. This review discusses the technique of SNM therapy, along with its complications and troubleshooting and a discussion of the early data pertaining to peripheral posterior tibial nerve stimulation in incontinent patients. Future work needs to define the predictive factors for neurostimulatory success, along with the likely mechanisms of action of their therapeutic action.

A review of posterior tibial nerve stimulation for faecal incontinence

AIM

This review aimed to assess the published results of posterior tibial nerve stimulation (PTNS) for faecal incontinence.

METHOD

A search was performed of PubMed, MEDLINE and Embase to identify studies describing the clinical outcome of PTNS for faecal incontinence.

RESULTS

Thirteen studies were identified. These described the outcome of PTNS for faecal incontinence in 273 patients. Four described transcutaneous PTNS, eight percutaneous PTNS and one compared both methods of PTNS with a sham transcutaneous group. One investigated patients with faecal incontinence and spinal cord injury and another with inflammatory bowel disease. There was marked heterogeneity of the treatment regimens and of the end points used. All reported that PTNS improved faecal incontinence. A > 50% improvement was reported in episodes of faecal incontinence in 63-82% of patients. An improvement was seen in urgency (1-5 min). Improvement was also described in the Cleveland Clinic faecal incontinence score in eight studies. Patients with urge and mixed incontinence appear to benefit more than those with passive incontinence. Treatment regimens ranged in duration from 1-3 months. A residual therapeutic effect is seen after completion of treatment. Follow-up ranged from 1-30 months.

CONCLUSION

PTNS is effective for faecal incontinence. However, many of the published studies are of poor quality. Comparison between studies is difficult owing to differences in the outcome measures used, technique of PTNS and the timing and duration of treatment.

Sacral neuromodulation for bowel dysfunction: a consensus statement from the Italian group

BACKGROUND

Representatives from the Italian centers experienced in sacral neuromodulation (SNM) for the treatment of bowel dysfunction met in order to define the current clinical practice in Italy and to produce a consensus statement regarding indications for this therapy and patient management.

METHODS

Fifty Italian colonproctologists were asked to complete a questionnaire concerning their clinical practice in SNM (290 questions, grouped within 4 broad areas). Physicians expressed their opinion by completing the questionnaire, assigning to each statement their level of agreement according to the 5-point Likert scale; the data were analyzed by attributing to each expert's answers a weight proportional to the degree of experience. During a meeting held 2 months later, the critical aspects of the therapy were re-examined and discussions held with the goal of reaching an agreement on controversial topics. The available literature was reviewed.

RESULTS

Patient selection criteria, etiology, diagnostic investigations, test procedures and implantation, follow-up and evaluation of results have been reviewed. The aim was to achieve an algorithm for patient management, showing the place of SNM in the treatment of bowel dysfunction. The approach in case of treatment failure was also discussed.

CONCLUSIONS

Analysis of the data collected reveals substantial consensus at the national level concerning all the main points with regard to the therapy. The recommendations expressed in this article can be considered as national guidelines and taken into account by the principal international implantation centers.

The effect of sacral nerve stimulation on distal colonic motility in patients with faecal incontinence

BACKGROUND

Sacral nerve stimulation (SNS) is an effective treatment for neurogenic faecal incontinence (FI). However, the clinical improvement that patients experience cannot be explained adequately by changes in anorectal function. The aim of this study was to examine the effect of SNS on colonic propagating sequences (PSs) in patients with FI in whom urgency and incontinence was the predominant symptom.

METHODS

In patients with FI a high-resolution fibre-optic manometry catheter, containing 90 sensors spaced at 1-cm intervals, was positioned colonoscopically and clipped to the caecum. A unipolar or quadripolar tined electrode was implanted into the S3 sacral nerve foramen. Colonic manometry was evaluated in a double-blind randomized crossover trial, using true suprasensory stimulation or sham stimulation. Each stimulation period, lasting 2 h, was preceded by a 2-h basal manometric recording.

RESULTS

All 11 patients studied showed a colonic response to SNS. In ten patients there was a significant increase in the frequency of retrograde PSs throughout the colon during true stimulation compared with sham stimulation (P = 0·014). In one outlier, with baseline retrograde PS frequency nine times that of the nearest patient, a reduction in retrograde PS frequency was recorded. Compared with sham stimulation, SNS had no effect on the frequency of antegrade PSs or high-amplitude PSs.

CONCLUSION

SNS modulates colonic motility in patients with faecal urge incontinence. These data suggest that SNS may improve continence and urgency through alteration of colonic motility, particularly by increasing retrograde PSs in the left colon.

Efficacy of cyclic sacral nerve stimulation for faecal incontinence

BACKGROUND

Sacral nerve stimulation (SNS) is an established treatment option for faecal incontinence. Cyclic stimulation will improve the longevity of the implanted stimulator, but little is known about its efficacy. The aim of this retrospective clinical study was to assess the efficacy of cyclic SNS for faecal incontinence.

METHODS

Sixty-three patients underwent percutaneous nerve evaluation (PNE) test with a 2-week period of continuous SNS. The PNE test was deemed positive in 42 patients (67 %) who underwent implantation with permanent stimulator. All 42 patients were initially stimulated in a cyclic manner with stimulation for 20 s followed by 8 s without. During follow-up, the stimulator was explanted in 2 patients and permanently turned off in one due to the loss of effect. A postal questionnaire including the Wexner score, a general quality of life (Qol) score, and a bowel habit diary was distributed to 39 patients.

RESULTS

The questionnaire was returned by 29/39 (74 %) of the patients. Median duration of follow-up was 16 (range 3-34) months. The Wexner score and the general QoL score were significantly improved compared to pre-treatment values. Some 18 patients (62 %) were still treated with cyclic stimulation at follow-up, reporting more frequent episodes of urgency without incontinence (p = 0.020) compared to symptoms during the PNE test. Patients who had changed to continuous stimulation due to a suboptimal effect during follow-up reported more frequent episodes of urgency with incontinence (p = 0.034), minor soiling (p = 0.045) and days wearing pads (p = 0.027) compared with symptoms during the PNE test.

CONCLUSIONS

Cyclic stimulation seems effective for most patients treated with SNS for faecal incontinence.

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.

Randomized double-blind crossover study of alternative stimulator settings in sacral nerve stimulation for faecal incontinence

Background

Sacral nerve stimulation is an established treatment for faecal incontinence. Nearly half of all patients experience loss of efficacy at some point. Standard reprogramming restores efficacy for some, but not all, patients. This study aimed to determine whether alternative stimulator settings would increase treatment efficacy.

Methods

Patients with sustained loss of efficacy were recruited from two international specialist centres. A number of alternative stimulation parameters were tested using a double-blind randomized crossover study design. Stimulation settings tested were pulse frequencies of 6·9 and 31 Hz, and pulse widths of 90 and 330 µs, compared with one standard setting of 14 Hz/210 µs. Treatment efficacy was evaluated using a disease-specific quality-of-life score (Fecal Incontinence Quality of Life Scale, FIQLS) and a bowel habit diary completed before randomization, during the study period and after 3 months of follow-up with one preferred setting.

Results

Fifteen patients were analysed. With one preferred setting, three of four subdomains in the FIQLS improved significantly. The mean(s.d.) total number of incontinence episodes dropped from 11·7(10·8) to 4·8(4·5) per 3 weeks (P = 0·011) and improvements were maintained after 3 months of follow-up. Optimal pacemaker settings were individual, but a trend towards highest patient satisfaction and improved treatment outcome was evident for high-frequency stimulation (31 Hz/210 µs), which was preferred by eight of the 15 patients.

Conclusion

Patients experiencing loss of efficacy can experience improvement if alternative pacemaker settings are tested. High-frequency stimulation (31 Hz/210 µs) was preferred by more than half of the patients, and improved treatment outcome was sustained at 3 months. Registration number: NCT01254695 (http://www.clinicaltrials.gov).

Functional results and patient satisfaction with sacral nerve stimulation for idiopathic faecal incontinence

AIM

Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence (FI) when conservative modalities have failed to restore continence. This two-centre study aimed to document functional outcome and its relationship to patient satisfaction.

METHOD

Patients treated with SNS for idiopathic FI in Aarhus (Denmark) and Maastricht (The Netherlands) were included. At the most recent follow-up appointment, 127 patients (80%) were identified as receiving active SNS therapy. A questionnaire considering bowel habits, quality of life, and self-reported satisfaction and a 3-week bowel-habit diary were mailed to these patients, and 85% responded.

RESULTS

Patient satisfaction was clearly related to the number of FI episodes. Patients experiencing full continence were all satisfied, and although the satisfaction rate decreased as the number of FI episodes increased, 46% of the patients with more FI episodes at follow-up than at baseline were still satisfied. Per-protocol analysis resulted in a satisfaction rate of 57.3%. In total, 74.7% of the patients receiving active SNS therapy reported a reduction of ≥ 50% in FI episodes, 10.3% of whom were dissatisfied after a median of 46 months of follow-up.

CONCLUSION

There is a clear relationship between patient satisfaction and improved continence. A total of 57.3% of the patients offered SNS therapy were satisfied at follow-up. However, 46% of the patients with more FI episodes at follow-up than at baseline were also satisfied. Therefore, functional outcome of SNS therapy cannot be based only on bowel-habit diaries and bowel scores.

Postoperative issues of sacral nerve stimulation for fecal incontinence and constipation: a systematic literature review and treatment guideline

BACKGROUND

There is a lack of knowledge on the incidence and management of suboptimal therapeutic effect and the complications associated with sacral nerve stimulation for fecal incontinence and constipation.

OBJECTIVE

This study aimed to review current literature on postoperative issues and to propose a treatment algorithm.

DATA SOURCE

PubMed, MEDLINE, and EMBASE were searched using the keywords "sacral nerve stimulation," "sacral neuromodulation," "fecal incontinence," and "constipation" for English-language articles published from January 1980 to August 2010. A further search was conducted on a wider literature using the keywords "complication," "adverse effect," "treatment failure," "equipment failure," "infection," "foreign-body migration," "reoperation," "pain," and "algorithm."

STUDY SELECTION

Four hundred sixty-one titles were identified, and after a title and abstract review, 135 were subjected to full article review; 89 were finally included in this review. Five articles were added by manual search and consensus.

RESULTS

Forty-eight studies were identified as cohort studies reporting on postoperative issues, including 1661 patients who underwent percutaneous nerve evaluation and 1600 patients who proceeded to sacral nerve stimulation therapy. Pooled data showed that the most common problem during percutaneous nerve evaluation was lead displacement (5.3%). The incidence of suboptimal outcome, pain, and infection after implantation was 12.1%, 13.0%, and 3.9%.

LIMITATIONS

There was significant underreporting of untoward events, because 60% of the studies did not report complications during percutaneous nerve evaluation, and suboptimal outcome after implantation was not disclosed in 44% of the studies.

CONCLUSIONS

The incidence of untoward events associated with sacral nerve stimulation appears to be low. However, there is a significant underreporting of the incidence. Using the information from the structured and systematic literature review, we formulated a clinically relevant guideline for reporting and managing postoperative issues. The guideline can provide a framework for clinical practice.

Sacral nerve stimulation for faecal incontinence: results from a single centre over a 10-year period

AIM

Sacral nerve stimulation (SNS) is considered a first-line surgical treatment option for faecal incontinence. There is little information on long-term results. The results of SNS for faecal incontinence performed at a single centre over a 10-year period are reported.

METHOD

A cohort analysis of consecutive patients treated with SNS for faecal incontinence over a 10-year period was carried out. Data were collected prospectively using bowel habit diaries and St Mark's and Cleveland Clinic incontinence scores. Treatment success was defined as a >50% reduction in episodes of faecal incontinence compared with baseline.

RESULTS

Temporary SNS was performed in 118 patients, and 91 (77%) were considered suitable for chronic stimulation. The median period of follow up was 22 (1-138) months. Seventy patients were followed for 1 year with success in 63 (90%). Of 18 patients followed for 5 years, 15 (83%) reported continued success, 11 (61%) maintained full efficacy, 4 (22%) reported some loss, and 3 (17%) reported complete loss. Three patients with a 10-year follow up had no loss in efficacy. Overall, complete loss of efficacy was observed in 14 (16%) patients at a median of 11.5 months following implantation. A further 5 (6%) patients showed deterioration with time. In 9 (47%), no reason for the deterioration in symptoms could be identified.

CONCLUSIONS

SNS can be effective for up to 10 years. Some patients experience deterioration in symptoms over time. The reasons for this are often not evident.

Sacral nerve stimulation for faecal incontinence: optimizing outcome and managing complications

AIM

A knowledge of the principles of neurostimulation is essential to achieve optimal efficacy and minimize adverse effects. The aim of this article was to review the current evidence regarding device programming in the management of patients having sacral nerve stimulation (SNS) for faecal incontinence.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of sacral nerve stimulation, neuromodulation, artificial pacemaker, faecal incontinence, programming, adverse effects and complications. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

Neurostimulator programming is an important component of SNS. Efficacy can be improved or restored with reprogramming. Adverse stimulation is often reversible, and nonstimulation-related complications are correctable. A total loss of efficacy can be explained in over one-half of patients.

CONCLUSION

An improved outcome of SNS can be achieved by selecting the best possible stimulation parameters individualized to each patient. Further research into the optimal settings is needed.

Future indications for sacral nerve stimulation

AIM

The aim of this article was to determine the effect of sacral nerve stimulation (SNS) on the treatment of faecal incontinence, constipation, irritable bowel syndrome, mixed urinary and bowel disorders, spinal injury and neurodegenerative disease, pain syndromes, and sexual dysfunction.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of 'sacral nerve stimulation', 'neuromodulation', 'artificial pacemaker', 'faecal incontinence', 'constipation' and 'anal pain'. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

SNS has been used for the treatment of urinary, bowel and sexual dysfunction, as well as pain resulting from such disorders, and dysfunction arising from nerve injury and degenerative disease. There is a paucity of high quality evidence to support the use of SNS for the majority of novel indications at present.

CONCLUSION

Good quality prospective, cross-over studies are required to determine the true benefits of SNS. Further research into patient selection, operative technique and stimulation parameters for existing indications will ensure a place for SNS in the future treatment algorithm of functional pelvic floor disorders.