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

Sensing in Sacral Neuromodulation: A Feasibility Study in Subjects With Urinary Incontinence and Retention

OBJECTIVES

Sacral neuromodulation (SNM) therapy standard of care relies on visual-motor responses and patient-reported sensory responses in deciding optimized lead placement and programming. Automatic detection of stimulation responses could offer a simple, consistent indicator for optimizing SNM. The purpose of this study was to measure and characterize sacral evoked responses (SERs) resulting from sacral nerve stimulation using a commercial, tined SNM lead.

MATERIALS AND METHODS

A custom external research system with stimulation and sensing hardware was connected to the percutaneous extension of an implanted lead during a staged (tined lead) evaluation for SNM. The system collected SER recordings across a range of prespecified stimulation settings (electrode configuration combinations for bipolar stimulation and bipolar sensing) during intraoperative and postoperative sessions in 21 subjects with overactive bladder (OAB) and nonobstructive urinary retention (NOUR). Motor and sensory thresholds were collected during the same sessions.

RESULTS

SERs were detected in all 21 subjects. SER morphology (number of peaks, magnitude, and timing) varied across electrode configurations within and across subjects. Among subjects and electrode configurations tested, recordings contained SERs at motor threshold and/or sensory threshold in 75% to 80% of subjects.

CONCLUSIONS

This study confirmed that implanted SNM leads can be used to directly record SERs elicited by stimulation in subjects with OAB and NOUR. SERs were readily detectable at typical SNM stimulation settings and procedural time points. Using these SERs as possible objective measures of SNM response has the capability to automate patient-specific SNM therapy, potentially providing consistent lead placement, programming, and/or closed-loop therapy.

A Predictive Model to Identify the Effects of Transcutaneous Sacral Nerve Stimulation With Pelvic Floor Exercises in Fecal Incontinence After Surgery for Anorectal Malformation

INTRODUCTION

Although the combination of transcutaneous sacral nerve stimulation (tSNS) and pelvic floor exercises (PFEs) has shown significant effectiveness in treating fecal incontinence (FI) after surgery for congenital anorectal malformation (CARM), not all patients achieve satisfactory continence. Therefore, identifying which individuals will benefit from this method is crucial.

METHODS

A prospective cohort study enrolled 92 children with FI. All patients underwent tSNS with PFE treatment, and an improved outcome was defined as a Wexner score ≤4. A predictive model to identify the effects of tSNS with PFEs in FI was developed based on the analysis of magnetic resonance imaging and high-resolution anorectal manometry with area under the receiver-operating characteristic curve to evaluate the predictive value of external anal sphincter (EAS) thickness index and anal squeezing pressure (ASP).

RESULTS

tSNS with PFEs improved outcomes in 72 patients and led to poor outcomes in 20 (4 had their rectums deviate from the puborectalis muscle center or puborectal muscle ruptures while 16 lacked EAS with a lower ASP). The areas under the receiver-operating characteristic curve for EAS thickness index and ASP in predicting the effects of tSNS with PFEs were 0.915 (95% confidence interval 0.846-0.983, P = 0.000) and 0.886 (95% confidence interval 0.819-0.952, P = 0.000), respectively. By applying cutoff values of 0.076 for EAS thickness index and 21.95 mm Hg for ASP, tSNS with PFEs was found to be ineffective.

DISCUSSION

tSNS with PFEs is effective for most patients with FI after CARM surgery, except when the rectum deviates from the puborectal muscle center, puborectal muscle rupture occurs, or EAS is absent with a low ASP.

Effect of pulse width variations on sacral neuromodulation for overactive bladder symptoms: A prospective randomized crossover feasibility study

INTRODUCTION/BACKGROUND

The pulse width (PW) parameter in sacral neuromodulation (SNM) is understudied, with no evidence-based guidance available on optimal PW for urinary indications. The aim of this prospective, randomized, single-blinded, 3 × 3 cross over design study was to estimate the effect of two PW settings (60 µs, 420 µs) compared to the industry standard (210 µs) on SNM efficacy, quality of life, and device parameters in patients who were stable and satisfied with their SNM treatment.

METHODS/MATERIALS

Eligible patients were previously implanted and had urge incontinence or urgency-frequency with satisfaction on SNM at time of enrollment. Patients completed a 3-day voiding diary, validated questionnaires, and device interrogations with sensory threshold assessment at baseline and after a 4-week period on each of the three PW settings, to which they were randomized. Eighteen participants completed the study, as called for by power analysis.

RESULTS

Eighteen patients were enrolled in the study. Mean age was 68 years and implant duration at the time of participation was 4.4 years. While PW variations did not produce significant differences in overall objective outcomes, device parameters, including sensory threshold amplitude and battery life differed significantly. Shortened PW necessitated higher amplitude while conserving battery life. Stimulus sensation location, quality, and intensity did not differ between PW. Standard PW was chosen by 11 patients after the study, 5 chose extended, and 2 chose shortened. Those who chose alternative PW achieved significant reductions in urinary frequency from enrollment -2.23 voids/day (p = 0.015). Upon sub-analysis, patients reporting "much better" or "very much better" on extended PW achieved significant reductions in urinary frequency and nocturia at 5.6 and 0.4, compared to 8.5 and 2.16 at baseline (p = 0.005, p = <0.001). Whereas those reporting "much better" or "very much better" on shortened PW achieved significant reductions in urinary frequency at 5.15 compared to 7.35 (p = 0.026). There were no adverse events or complications.

CONCLUSIONS

Overall SNM effectiveness was unchanged with alternative PW; however, 39% of patients preferred alternative to standard PW and achieved significant improvements in urinary symptoms with such. Shorter PW can also provide savings in estimated battery life without sacrificing therapeutic efficacy.

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.

Bioelectronic medicine for the autonomic nervous system: clinical applications and perspectives

Bioelectronic medicine (BM) is an emerging new approach for developing novel neuromodulation therapies for pathologies that have been previously treated with pharmacological approaches. In this review, we will focus on the neuromodulation of autonomic nervous system (ANS) activity with implantable devices, a field of BM that has already demonstrated the ability to treat a variety of conditions, from inflammation to metabolic and cognitive disorders. Recent discoveries about immune responses to ANS stimulation are the laying foundation for a new field holding great potential for medical advancement and therapies and involving an increasing number of research groups around the world, with funding from international public agencies and private investors. Here, we summarize the current achievements and future perspectives for clinical applications of neural decoding and stimulation of the ANS. First, we present the main clinical results achieved so far by different BM approaches and discuss the challenges encountered in fully exploiting the potential of neuromodulatory strategies. Then, we present current preclinical studies aimed at overcoming the present limitations by looking for optimal anatomical targets, developing novel neural interface technology, and conceiving more efficient signal processing strategies. Finally, we explore the prospects for translating these advancements into clinical practice.

A prospective, multicenter, international study to explore the effect of three different amplitude settings in female subjects with urinary urge incontinence receiving interstim therapy

Aims

The aim of this study is to evaluate the effect of sub‐sensory amplitude settings of sacral neuromodulation therapy on overactive bladder symptoms in subjects with urinary urge incontinence.

Methods

Subjects who qualified for a neurostimulator device implant were randomized to one of three amplitude settings (50% of sensory threshold [ST], 80% of ST, and ST). Subjects completed urinary voiding diaries (3‐day), International consultation on incontinence modular questionnaire—overactive bladder symptoms quality of life questionnaire, and patient global impression of improvement (PGI‐I) to assess change in voiding symptoms and quality of life (QoL) from baseline through 12 weeks.

Results

Forty‐eight subjects had a successful test stimulation, 46 were implanted with a neurostimulator device and 43 completed the 12‐week follow‐up visit. The change from baseline to 12 weeks is −3.0 urinary incontinence (UI) episodes/day (95% confidence interval [CI]: −4.4 to −1.7) for the 50% of sensory threshold group, −2.9 UI episodes/day (95% CI: −4.7 to −1.2) for 80% of sensory threshold group, and −3.6 UI episodes/day (95% CI: −5.2 to −1.9) for the sensory threshold group. In each randomized group, improvements were observed in health‐related QoL, its subscales, and symptom interference. Subjects across all three randomization groups reported on the PGI‐I that their bladder condition was better at 12 weeks compared to before they were treated with InterStim therapy.

Conclusion

These findings provide insights into possible advancements in the postimplantation phase of therapy with potential for improved patient comfort and increased device longevity.

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.

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.

Tools for fecal incontinence assessment: lessons for inflammatory bowel disease trials based on a systematic review

BACKGROUND

Fecal incontinence is a disabling condition affecting up to 20% of women.

OBJECTIVE

We investigated fecal incontinence assessment in both inflammatory bowel disease and non-inflammatory bowel disease patients to propose a diagnostic approach for inflammatory bowel disease trials.

METHODS

We searched on Pubmed, Embase and Cochrane Library for all studies on adult inflammatory bowel disease and non-inflammatory bowel disease patients reporting data on fecal incontinence assessment from January 2009 to December 2019.

RESULTS

In total, 328 studies were included; 306 studies enrolled non-inflammatory bowel disease patients and 22 studies enrolled inflammatory bowel disease patients. In non-inflammatory bowel disease trials the most used tools were the Wexner score, fecal incontinence quality of life questionnaire, Vaizey score and fecal incontinence severity index (in 187, 91, 62 and 33 studies). Anal manometry was adopted in 41.2% and endoanal ultrasonography in 34.0% of the studies. In 142 studies (46.4%) fecal incontinence evaluation was performed with a single instrument, while in 64 (20.9%) and 100 (32.7%) studies two or more instruments were used. In inflammatory bowel disease studies the Wexner score, Vaizey score and inflammatory bowel disease quality of life questionnaire were the most commonly adopted tools (in five (22.7%), five (22.7%) and four (18.2%) studies). Anal manometry and endoanal ultrasonography were performed in 45.4% and 18.2% of the studies.

CONCLUSION

Based on prior validation and experience, we propose to use the Wexner score as the first step for fecal incontinence assessment in inflammatory bowel disease trials. Anal manometry and/or endoanal ultrasonography should be taken into account in the case of positive questionnaires.

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.

Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms

The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn's disease in a single trial. Pulses of high-frequency current applied to the vagus nerve have been used to block signalling from the stomach to the brain to reduce appetite with variable outcomes. Bioelectric neuromodulation has also been investigated for postoperative ileus, gastroparesis symptoms and constipation in animal models and some clinical trials. The clinical success of this bioelectric neuromodulation therapy might be enhanced through better knowledge of the targeted nerve pathways and their physiological and pathophysiological roles, optimizing stimulation protocols and determining which patients benefit most from this therapy.

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.

Sacral Neuromodulation for Fecal Incontinence: A Review of the Central Mechanisms of Action

OBJECTIVE

Fecal incontinence (FI) has a devastating effect on the quality of life and results in social isolation. Sacral neuromodulation (SNM) is proven to be an effective, minimal invasive treatment modality for FI. Despite the increasing application of SNM, the exact mechanisms of action remain unclear. The initial assumption of peripheral motor neurostimulation is not supported by increasing evidence, which report effects of SNM outside the pelvic floor. A new hypothesis states that afferent signals to the brain are essential for a successful therapy. This study aimed to review relevant studies on the central mechanism of SNM in FI.

METHODS

Clinical and experimental studies on the central mechanisms, both brain and spinal cord, of SNM for FI up to December 2015 were evaluated.

RESULTS

In total, 8 studies were found describing original data on the central mechanism of SNM for FI. Four studies evaluated the central effects of SNM in a clinical setting and 4 studies evaluated the central effects of SNM in an experimental animal model. Results demonstrated a variety of (sub)cortical and spinal changes after induction of SNM.

CONCLUSION

Review of literature demonstrated evidence for a central mechanism of action of SNM for FI. The corticoanal pathways, brainstem, and specific parts of the spinal cord are involved.

Fecal Incontinence: Epidemiology, Impact, and Treatment

Fecal incontinence (FI) is a chronic and debilitating condition that carries a significant health, economic, and social burden. FI has a considerable psychosocial and financial impact on patients and their families. A variety of treatment modalities are available for FI including behavioral and dietary modifications, pharmacotherapy, pelvic floor physical therapy, bulking agents, anal sphincteroplasty, sacral nerve stimulation, artificial sphincters, magnetic sphincters, posterior anal sling, and colostomy.

Endpoints for therapeutic interventions in faecal incontinence: small step or game changer

Faecal incontinence (FI) is common and its pathophysiology and treatments continue to evolve. However, a standard measure(s) for assessing its clinical outcome has been elusive. Consequently, over 100 measures and scoring systems, each with intrinsic biases have been reported. These include adequate relief or global satisfaction, ≥50% reduction in episodes or days without FI, quality of life (QOL), FI severity scales and composite indices. Earlier scales relied on the frequency and type of solid, liquid or flatus incontinence and effects on life style whereas newer scales have incorporated urgency, use of pads, antidiarrhoeals and amount of leakage, using prospective daily stool diaries or retrospective weekly or single point assessments. Such a plethora of measures have negatively impacted the assessment and outcome of clinical trials, and have made comparisons difficult. So, how does one sort out the grain from the chaff? In a provocative, post-hoc analysis published in this issue, the minimal clinically important difference, i.e. the smallest change detected by an instrument that is associated with a clinically meaningful change was used to assess FI endpoint. Based on this a ≥50% reduction in FI episodes is recommended as a clinically meaningful outcome measure when assessed by prospective stool diary, and it correlates with symptoms and severity. However, this requires further validation in multi-centre, longer duration and therapeutically effective clinical trial(s). Simultaneous assessment of coping strategies, QOL and psychosocial domains can provide further insights regarding the overall impact of treatments. This mini-review discusses the advances and controversies in defining meaningful FI endpoints.

Systematic Review of Surgical Treatments for Fecal Incontinence

BACKGROUND

No systematic review has examined the collective randomized and nonrandomized evidence for fecal incontinence treatment effectiveness across the range of surgical treatments.

OBJECTIVE

The purpose of this study was to assess the efficacy, comparative effectiveness, and harms of surgical treatments for fecal incontinence in adults.

DATA SOURCES

Ovid MEDLINE, EMBASE, Physiotherapy Evidence Database, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine, and the Cochrane Central Register of Controlled Trials, as well as hand searches of systematic reviews, were used as data sources.

STUDY SELECTION

Two investigators screened abstracts for eligibility (surgical treatment of fecal incontinence in adults, published 1980-2015, randomized controlled trial or observational study with comparator; case series were included for adverse effects). Full-text articles were reviewed for patient-reported outcomes. We extracted data, assessed study risk of bias, and evaluated strength of evidence for each treatment-outcome combination.

INTERVENTIONS

Surgical treatments for fecal incontinence were included interventions.

MAIN OUTCOME MEASURES

Fecal incontinence episodes/severity, quality of life, urgency, and pain were measured.

RESULTS

Twenty-two studies met inclusion criteria (13 randomized trials and 9 observational trials); 53 case series were included for harms. Most patients were middle-aged women with mixed FI etiologies. Intervention and outcome heterogeneity precluded meta-analysis. Evidence was insufficient for all of the surgical comparisons. Few studies examined the same comparisons; no studies were high quality. Functional improvements varied; some authors excluded those patients with complications or lost to follow-up from analyses. Complications ranged from minor to major (infection, bowel obstruction, perforation, and fistula) and were most frequent after the artificial bowel sphincter (22%-100%). Major surgical complications often required reoperation; few required permanent colostomy.

LIMITATIONS

Most evidence is intermediate term, with small patient samples and substantial methodologic limitations.

CONCLUSIONS

Evidence was insufficient to support clinical or policy decisions for any surgical treatments for fecal incontinence in adults. More invasive surgical procedures had substantial complications. The lack of compliance with study reporting standards is a modifiable impediment in the field. Future studies should focus on longer-term outcomes and attempt to identify subgroups of adults who might benefit from specific procedures.

Impact of fecal incontinence and its treatment on quality of life in women

Fecal incontinence (FI) is a physically and psychosocially debilitating disorder which negatively impacts quality of life (QOL). It bears a significant burden not only on patients but also on their families, caretakers as well as society as a whole. Even though it is considered a somewhat common condition, especially as women age, the prevalence is often underestimated due to patients' reluctance to report symptoms or seek care. The evaluation and treatment of FI can be also hindered by lack of understanding of the current management options among healthcare providers and how they impact on QOL. This article provides a comprehensive review on the impact of FI and its treatment on QOL in women.

Bilateral compared with unilateral sacral nerve stimulation for faecal incontinence: results of a randomized, single-blinded crossover study

AIM

This randomized single-blinded crossover study aimed to investigate whether bilateral sacral nerve stimulation (SNS) is more efficient than unilateral stimulation for faecal incontinence (FI).

METHOD

Patients with FI who responded during a unilateral test stimulation, with a minimum improvement of 50% were eligible. Twenty-seven patients who were accepted to enter the trial were bilaterally implanted with two permanent leads and pacemakers. Patients were randomized into three periods of 4 weeks' stimulation including unilateral right, unilateral left and bilateral stimulation. Symptoms scores and bowel habit diaries were collected at baseline and in each study period. A 1-week washout was introduced between each study period.

RESULTS

Twenty-seven (25 female) patients with a median age of 63 (36-84) years were bilaterally implanted from May 2009 to June 2012. The median number of episodes of FI per 3 weeks significantly decreased from 17 (3-54) at baseline to 2 (0-20) during stimulation on the right side, 2 (0-42) during stimulation on the left side and 1 (0-25) during bilateral stimulation. The Wexner incontinence score improved significantly from a median of 16 (10-20) at baseline to 9 (0-14) with right-side stimulation, 10 (0-15) with left-side stimulation and 9 (0-14) with bilateral stimulation. The differences between unilateral right or unilateral left and bilateral stimulation were non-significant, for FI episodes (P = 0.3) or for Wexner incontinence score (P = 0.9).

CONCLUSION

Bilateral SNS therapy for FI is not superior to standard unilateral stimulation in the short term. Equal functional results can be obtained regardless of the side of implantation.

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.

A pilot study of chronic pudendal nerve stimulation for faecal incontinence for those who have failed sacral nerve stimulation

BACKGROUND

Sacral nerve stimulation (SNS) is used as a first-line treatment for faecal incontinence when conservative measures have failed. However, one-third of patients fail to benefit from this treatment. We hypothesised that sacral afferent stimulation can be maximised using pudendal nerve stimulation (PNS) and this may be of benefit in this patient group. The aim of this study was to assess chronic PNS for those who failed to improve with SNS.

METHODS

Ten patients who had failed SNS were recruited. All underwent percutaneous insertion of a stimulation lead with four-electrode array adjacent to the pudendal nerve. Continuous bipolar stimulation was administered using an external pulse generator over a 3-week period. Those who experienced a ≥50% reduction in the frequency of incontinent episodes over this period proceeded to chronic stimulation with an implantable pulse generator.

RESULTS

Five patients experienced a ≥50% reduction of incontinent episodes during test stimulation and proceeded to chronic stimulation. In these five patients, at a median (range) follow-up of 24 (6-36) months, the median (inter quartile range) frequency of incontinent episodes reduced from 5 (18.25) to 2.5 (3) per week (p = 0.043). Three patients maintained a ≥50% improvement in soiling. There was an improvement in the St Mark's continence Score from 19 (15-24) to 16 (13-19), p = 0.042. There were no significant changes in ability to defer defecation or in quality of life scores.

CONCLUSIONS

Pudendal nerve stimulation failed to improve the symptoms in the majority of patient who had failed SNS. Only a third experienced any improvement.