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

Unintentionally intentional: unintended effects of spinal stimulation as a platform for multi-modal neurorehabilitation after spinal cord injury

Electrical stimulation of spinal neurons has emerged as a valuable tool to enhance rehabilitation after spinal cord injury. In separate parameterizations, it has shown promise for improving voluntary movement, reducing symptoms of autonomic dysreflexia, improving functions mediated by muscles of the pelvic floor (e.g., bowel, bladder, and sexual function), reducing spasms and spasticity, and decreasing neuropathic pain, among others. This diverse set of actions is related both to the density of sensorimotor neural networks in the spinal cord and to the intrinsic ability of electrical stimulation to modulate neural transmission in multiple spinal networks simultaneously. It also suggests that certain spinal stimulation parameterizations may be capable of providing multi-modal therapeutic benefits, which would directly address the complex, multi-faceted rehabilitation goals of people living with spinal cord injury. This review is intended to identify and characterize reports of spinal stimulation-based therapies specifically designed to provide multi-modal benefits and those that report relevant unintended effects of spinal stimulation paradigms parameterized to enhance a single consequence of spinal cord injury.

Effectiveness, safety and cost-effectiveness of sacral neuromodulation for idiopathic slow-transit constipation: a systematic review

AIM

Sacral neuromodulation (SNM) is a minimally invasive treatment option for functional constipation. Evidence regarding its effectiveness is contradictory, driven by heterogeneous study populations and designs. The aim of this study was to assess the effectiveness, safety and cost-effectiveness of SNM in children and adults with refractory idiopathic slow-transit constipation (STC).

METHOD

OVID Medline, OVID Embase, Cochrane Library, the KSR Evidence Database, the NHS Economic Evaluation Database and the International HTA Database were searched up to 25 May 2023. For effectiveness outcomes, randomized controlled trials (RCTs) were selected. For safety outcomes, all study designs were selected. For cost-effectiveness outcomes, trial- and model-based economic evaluations were selected for review. Study selection, risk of bias and quality assessment, and data extraction were independently performed by two reviewers. For the intervention 'sacral neuromodulation' effectiveness outcomes included defaecation frequency and constipation severity. Safety and cost-effectiveness outcomes were, respectively, adverse events and incremental cost-effectiveness ratios.

RESULTS

Of 1390 records reviewed, 67 studies were selected for full-text screening. For effectiveness, one cross-over and one parallel-group RCT was included, showing contradictory results. Eleven studies on safety were included (four RCTs, three prospective cohort studies and four retrospective cohort studies). Overall infection rates varied between 0% and 22%, whereas reoperation rates varied between 0% and 29%. One trial-based economic evaluation was included, which concluded that SNM was not cost-effective compared with personalized conservative treatment at a time horizon of 6 months. The review findings are limited by the small number of available studies and the heterogeneity in terms of study populations, definitions of refractory idiopathic STC and study designs.

CONCLUSION

Evidence for the (cost-)effectiveness of SNM in children and adults with refractory idiopathic STC is inconclusive. Reoperation rates of up to 29% were reported.

Is percutaneous tibial nerve stimulation (PTNS) effective for fecal incontinence (FI) in adults compared with sham electrical stimulation? A meta-analysis

BACKGROUND

Sacral nerve neuromodulation (SNM) has been considered the optimal second-line treatment for fecal incontinence (FI). However, SNM involves high cost and requires highly skilled operators. Percutaneous tibial nerve stimulation (PTNS) has emerged as an alternative treatment modality for FI, yielding varying clinical outcomes. We conducted this meta-analysis to evaluate the effectiveness and safety of PTNS compared to sham electrical stimulation for FI.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched for studies from May 12, 2012 to May 12, 2022.

RESULTS

Four randomized controlled studies were included in this review, involving a total of 439 adult patients with FI (300 in the PTNS group and 194 in the sham electrical stimulation group). Our meta-analysis revealed that PTNS demonstrated superior efficacy in reducing weekly episodes of FI compared to the control groups (MD - 1.6, 95% CI - 2.94 to - 0.26, p = 0.02, I2 = 30%). Furthermore, a greater proportion of patients in the PTNS group reported more than a 50% reduction in FI episodes per week (RR 0.73, 95% CI 0.57-0.94, p = 0.02, I2 = 6%). However, no significant differences were observed in any domains of the FI Quality of Life (QoL) and St Mark's incontinence scores (MD - 2.41, 95% CI - 5.1 to 0.27, p = 0.08, I2 = 67%). Importantly, no severe adverse events related to PTNS were reported in any of the participants.

CONCLUSIONS

Our meta-analysis revealed that PTNS was more effective than sham stimulation in reducing FI episodes and led to a higher proportion of patients reporting more than a 50% reduction in weekly FI episodes.

Clinical characteristics of phenotypes of fecal incontinence

PURPOSE

Fecal incontinence (FI) is common, but its etiology is complex with large knowledge gaps. Several phenotypes of FI are known, but the phenotype is often not decisive in the chosen therapy. In this study we aimed to assess the association of the clinical characteristics of patients with FI and the various phenotypes, in order to establish a targeted clinical treatment decision tree.

METHODS

We retrospectively studied the charts of patients with FI, who visited our institute from January 2018 until December 2020. Patients were divided into the following groups: passive fecal loss, urge incontinence, combined fecal incontinence with predominantly passive fecal loss, and combined fecal incontinence with predominantly urge incontinence. We compared the characteristics between the passive and urge incontinence groups, the passive  and combined mainly passive groups, and the urge and combined mainly urge groups.

RESULTS

Patients with passive incintinence were older, more often had a flaccid anus with presence of a mucosal prolapse, and had a lower resting pressure on anorectal manometry. Patients with urge incontinence were younger and more often had a history of birth trauma. The combined groups showed characteristics of both of the main types of FI.

CONCLUSION

Differentiating into phenotypes of FI can be clinically meaningful. The patient history and clinical judgement of the consulting specialist, rather than the physical characteristics, seem to be decisive in the categorization. Additional diagnostic testing can be helpful in complicated cases, but should not be used routinely.

[Sacral Neuromodulation for Fecal Incontinence and Constipation: Evidence, Programming and Long-term Management]

BACKGROUND

Over the last two decades, sacral neuromodulation (SNM) has established its role in the treatment of functional pelvic organ-/pelvic floor disorders. Even though the mode of action is not fully understood, SNM has become the preferred surgical treatment of fecal incontinence.

METHODS AND RESULTS

A literature search was carried out on programming sacral neuromodulation and long-term outcomes in treating fecal incontinence and constipation.Sacral neuromodulation was found to be successful in the long term. Over the years, the spectrum of indications has expanded, and now includes patients presenting with anal sphincter lesions. The use of SNM for low anterior resection syndrome (LARS) is currently under clinical investigation. Findings of SNM for constipation are less convincing. In several randomised crossover studies, no success was demonstrated, even though it is possible that subgroups may benefit from the treatment. Currently the application cannot be recommended in general.The pulse generator programming sets the electrode configuration, amplitude, pulse frequency and pulse width. Usually pulse frequency and pulse width follow a default setting (14 Hz, 210 s), while electrode configuration and stimulation amplitude are adjusted individually to the patient need and perception of stimulation.Despite low infection rates and few electrode-/pulse generator dysfunctions, up to 65% of patients require surgical reintervention during long term follow-up - in 50% of cases because of battery depletion, which is an expected event. At least one reprogramming is necessary in about 75% of the patients during the course of the treatment, mostly because of changes in effectiveness, but rarely because of pain. Regular follow-up visits appear to be advisable.

CONCLUSION

Sacral neuromodulation can be considered to be a safe and effective long-term therapy of fecal incontinence. To optimise the therapeutic effect, a structured follow-up regime is advisable.

Sensory brain activation during rectal balloon distention: a pilot study in healthy volunteers to assess safety and feasibility at 1.5T

OBJECTIVE

Although increasing evidence suggests a central mechanism of action for sacral neuromodulation, the exact mechanism remains unclear. We set up a scanning paradigm to measure brain activation related to various stages of rectal filling using rectal balloon distention.

MATERIALS AND METHODS

Six healthy volunteers underwent rectal balloon distention during MRI scanning at a 1.5T scanner with a Tx/Rx head coil. MR images were collected at four levels of distention: empty balloon (EB), first sensation volume (FSV), desire to defecate volume (DDV), maximum tolerable volume (MTV). Data were analyzed using BrainVoyager 20.4. Whole brain and ROI-based fixed-effects general linear model analyses were performed on the fMRI time-course data from all participants.

RESULTS

Rectal filling until FSV evoked the most blood-oxygen-level-dependent responses in several clusters throughout the cortex, followed by the responses evoked by rectal filling until DDV. Interestingly, rectal filling until MTV evoked negative responses compared to baseline throughout the cortex. No negative side effects were found.

DISCUSSION

This study shows that a standardized paradigm for functional MRI combined with rectal filling is feasible and safe in healthy volunteers and is ready to be used in fecal incontinent patients to assess whether their brain activity differs from healthy controls.

Non-retentive faecal incontinence in children: Conventional therapy alone or combined electrical stimulation

AIMS

To compare the effects of functional electrical stimulation (FES) with conventional therapy and conventional therapy alone on improvement of faecal incontinence (FI) symptoms in a number of children with functional non-retentive FI.

METHODS

Data of 28 children with FI were accepted for this retrospective study. The case group (n = 14) underwent FES + conventional therapy and the control group (n = 14) received conventional therapy only. Data of children with faecal retention, inflammatory, anatomic, metabolic and neurological disorders were excluded. Children were assessed with a paediatric FI score questionnaire, and a bowel habit diary both before treatment sessions, after they ended, and after 6 months. A FI quality of life questionnaire was completed before and after treatment for all children.

RESULTS

Full response to the treatment (100% reduction in FI episodes) was significantly observed in 8/14 (57.1%) of children in the case group compared to 2/14 (14.2%) of children in the control group after the ending of treatment sessions (P = 0.005). The baseline mean ± SD of FI episodes per week was 3.7 ± 2.1 among both groups which significantly decreased after the ending of treatment sessions in the case group compared to the control group (1.4 ± 2.1 vs 3 ± 2.7; P = 0.05). Mean ± SD of FI score was significantly reduced in the case group compared to the controls after the ending of treatment sessions (3.9 ± 4.5 vs 8 ± 4.7; P = 0.02) and maintained after 6 months (P = 0.05).

CONCLUSIONS

Functional electrical stimulation is a safe, effective, non-invasive, inexpensive, reproducible and easy-to-use modality for treatment of functional non-retentive faecal incintinence in children.

Neuromodulation Strategies to Reduce Inflammation and Improve Lung Complications in COVID-19 Patients

Since the outbreak of the COVID-19 pandemic, races across academia and industry have been initiated to identify and develop disease modifying or preventative therapeutic strategies has been initiated. The primary focus has been on pharmacological treatment of the immune and respiratory system and the development of a vaccine. The hyperinflammatory state (“cytokine storm”) observed in many cases of COVID-19 indicates a prognostically negative disease progression that may lead to respiratory distress, multiple organ failure, shock, and death. Many critically ill patients continue to be at risk for significant, long-lasting morbidity or mortality. The human immune and respiratory systems are heavily regulated by the central nervous system, and intervention in the signaling of these neural pathways may permit targeted therapeutic control of excessive inflammation and pulmonary bronchoconstriction. Several technologies, both invasive and non-invasive, are available and approved for clinical use, but have not been extensively studied in treatment of the cytokine storm in COVID-19 patients. This manuscript provides an overview of the role of the nervous system in inflammation and respiration, the current understanding of neuromodulatory techniques from preclinical and clinical studies and provides a rationale for testing non-invasive neuromodulation to modulate acute systemic inflammation and respiratory dysfunction caused by SARS-CoV-2 and potentially other pathogens. The authors of this manuscript have co-founded the International Consortium on Neuromodulation for COVID-19 to advocate for and support studies of these technologies in the current coronavirus pandemic.

Fecal Incontinence: The Importance of a Structured Pathophysiological Model

Fecal incontinence has an enormous social and economic impact and may significantly impair quality of life. Even though fecal incontinence is a common complaint in (aging) adults, a structured pathophysiological model of the clinical presentations of fecal incontinence is missing in current literature. The most frequent manifestations of fecal incontinence are passive fecal loss, urge incontinence, or mixed fecal incontinence. At our institution, we treat 400 patients per year with defecation disorders, including a significant number of patients with fecal incontinence. On the basis of this experience, we have tried to create a concept that merges current insight in causes and treatment options in a clinically useful algorithm. By applying the system of anamnesis and physical examination described in this article and expanding it with simple additional anorectal examination, in most patients, one can determine the type of fecal incontinence and choose a targeted therapy.

Long-term results of sacral neuromodulation for the treatment of anorectal diseases

INTRODUCTION

Sacral neuromodulation (SNM) aims to improve anorectal function in patients with disorders of anal continence and rectal emptying. The mechanism of action of SNM is not well known, and its indications are still under evaluation. We report the functional results and morbidity of a prospective cohort treated between 2002 and 2019.

RESULTS

A total of 284 patients (of 423 tested) had implantation of a SNM. Five patients (1.8%) were lost to follow-up. Among those who had implantation, the indications for SNM were anal incontinence (n=376), refractory constipation (n=17), anterior resection syndrome (n=13), solitary rectal ulcer syndrome (n=7), and chronic inflammatory bowel disease (IBD) (n=10). The morbidity rate was 2.7% (Dindo-Clavien>2), 33 patients (11%) required explantation for infection (n=5), pain (n=2), inefficacy (n=24) or other reasons (rectal cancer) (n=3). It was necessary to change the stimulator in 68 patients (24%) during the follow-up period. Regarding the group of patients with anal incontinence, functional results showed improvement of the incontinence score in 40% and of quality of life in 25% after a mean follow-up of 55months.

CONCLUSION

SNM constitutes a mini-invasive treatment associated with low morbidity. Its' efficacy in anal incontinence makes it a priority approach. Other indications are still under evaluation; while results are promising, they are highly variable.

Current Incidence and Risk Factors of Fecal Incontinence After Acute Stroke Affecting Functionally Independent People

Background: Previously published retrospective series show a high prevalence of fecal incontinence (FI) in stroke patients. We aimed to analyze in a prospective series the current incidence of FI in acute stroke in functionally independent patients and its evolution over time and the patient characteristics associated with the appearance of FI in acute stroke. Methods: We included consecutive patients with acute stroke admitted in our stroke unit who fulfilled the following inclusion criteria: a first episode of stroke, aged >18 years, with no previous functional dependency [modified Rankin Scale (mRS) ≤ 2] and without previous known FI. FI was assessed by a multidisciplinary trained team using dedicated questionnaires at 72 ± 24 h (acute phase) and at 90 ± 15 days (chronic phase). Demographic, medical history, clinical and stroke features, mortality, and mRS at 7 days were collected. Results: Three hundred fifty-nine (48.3%) of 749 patients (mean age 65.9 ± 10, 64% male, 84.1% ischemic) fulfilled the inclusion criteria and were prospectively included during a 20-month period. FI was identified in 23 patients (6.4%) at 72 ± 24 h and in 7 (1.9%) at 90 days ± 15 days after stroke onset. FI was more frequent in hemorrhagic strokes (18 vs. 5%, p 0.007) and in more severe strokes [median National Institute of Health Stroke Scale (NIHSS) 18 (14-22) vs. 5 (3-13), p < 0.0001]. No differences were found regarding age, sex, vascular risk factors, or other comorbidities, or affected hemisphere. Patients with NIHSS ≥12 (AUC 0.81, 95% CI 0.71 to 0.89) had a 17-fold increase for the risk of FI (OR 16.9, IC 95% 4.7-60.1) adjusted for covariates. Conclusions: At present, the incidence of FI in acute stroke patients without previous functional dependency is lower than expected, with an association of a more severe and hemorrhagic stroke. Due to its impact on the quality of life, it is necessary to deepen the knowledge of the underlying mechanisms to address therapeutic strategies.

[Anal incontinence]

Anal incontinence describes the uncontrolled transanal passage of gaseous, solid or liquid intestinal contents. It can be a considerable psychosocial burden and impairment of the quality of life for those affected. The cause can be primary damage to the continence organ or incontinence can be a secondary symptom of other diseases. The detailed patient history and clinical examination document the severity of incontinence, impairment of quality of life and pathomorphological changes. The treatment is primarily conservative. A combination of conservative therapeutic approaches can often achieve satisfactory symptom relief. If conservative treatment remains insufficient, surgical measures can be considered. Sphincteroplasty and sacral neuromodulation are the preferred surgical interventions.

Percutaneous tibial nerve stimulation in patients with severe low anterior resection syndrome: randomized clinical trial

BACKGROUND

Treatment of low anterior resection syndrome (LARS) is challenging. Percutaneous tibial nerve stimulation (PTNS) can improve select bowel disorders. An RCT was conducted to assess the efficacy of PTNS compared with sham stimulation in patients with severe LARS.

METHOD

This was a multicentre, double-blind RCT. Patients with major LARS score were allocated to receive PTNS or sham therapy (needle placement simulation without nerve stimulation). The study included 16 sessions of 30 min once a week for 12 consecutive weeks, followed by four additional sessions once a fortnight for the following 4 weeks. The primary endpoint was efficacy of PTNS defined by the LARS score 12 months after treatment. Secondary endpoints included faecal incontinence, quality of life (QoL), and sexual function.

RESULTS

Between September 2016 and July 2018, 46 eligible patients were assigned randomly in a 1 : 1 ratio to PTNS or sham therapy. Baseline characteristics were similar. LARS scores were reduced in both groups, but only patients who received PTNS maintained the effect in the long term (mean(s.d.) score 36.4(3.9) at baseline versus 30.7(11.5) at 12 months; P = 0.018; effect size -5.4, 95 per cent c.i. -9.8 to -1.0), with a mean reduction of 15.7 per cent at 12-month follow-up. The faecal incontinence score was improved after 12 months in the PTNS group (mean(s.d.) score 15.4(5.2) at baseline versus 12.5(6.4) at 12 months; P = 0.018). No major changes in QoL and sexual function were observed in either group. There was no therapy-associated morbidity. Three patients discontinued the study, but none owing to study-related issues.

CONCLUSION

PTNS has positive effects in some patients with major LARS, especially in those with faecal incontinence. Registration number: NCT02517853 (http://www.clinicaltrials.gov).

Case Report: Sacral Nerve Root Pelvic Neural Retraining, With Long-Term Sustainability After the Device Explantation

Introduction: Sacral-Nerve-Neuromodulation (SNM) is an effective treatment increasingly used in patients with urinary (UI) and fecal incontinence (FI). The way it acts in the body at its full potential have not yet been elucidated. The authors review the literature on SNM and the way it possibly works, relating it to a case with an unusually favorable outcome.

Case Presentation: A female presented with UI and FI. Operated for meningocele as a neonate. It the age of 5 bilateral Cohen ureter reimplantation performed for persistent urinary infections due to vesicourethral reflux. At the age of 13, she started complaining about UI associated with a hyper functional detrusor muscle. After a diary incontinence evaluation with a standardized questionnaire, SNM was applied at the age of 18 and was retained for 4 years. She was re-evaluated with a yearly follow-up.

Results: The patient retained the positive effect of SNM even after its removal and in addition showed signs of improvement. The patient developed the sensation of fillingness of the bladder and the rectum, which she never had before the SNM implantation, sensation which she retained 29 months after (last follow-up) device removal, allowing her to control her voids.

Discussion: The modern literature hypothesis that SNM contributes to the plasticity of the nerves through the stimulated area is supported by the present case, in which the SNM effect remained and led to improvements even after its removal. Device settings are presented as they may correlate with the result. This reinforces and expands the frontiers of SNM application and research.

Sacral neuromodulation with the InterStim™ system for faecal incontinence: results from a prospective French multicentre observational study

AIM

The aim of this work was to evaluate the effectiveness, patient satisfaction and quality of life (QoL) and the safety of sacral neuromodulation (SNM) with the InterStim^TM system for the treatment of faecal incontinence (FI) and establish whether results published predominantly by expert sites are generalisable.

METHOD

This is a prospective, multicentre, observational study that invited all French sites treating FI with the InterStim™ system to enrol subjects indicated for an SNM therapy evaluation. Data were collected at three follow-up visits within 1 and 15 months. Therapeutic effectiveness was evaluated by the reduction in leakages per week and improvements over time in the ability to defer defaecation and QoL (as measured with the Faecal Incontinence Quality of Life score). Safety was assessed through reported adverse events.

RESULTS

A total of 221 subjects with a mean age of 62.1 years were tested (184 women) and 178 received a permanent implant. For all implanted subjects with diary data at baseline and follow-up, a reduction in leakage of more than 50% was observed in 80%, 76% and 83% at 1-3, 4-8 and 9-15 months, respectively. The mean number of leakage episodes and urgency improved significantly compared with the baseline (p < 0.0001). Subjects showed improvements in QoL and time to defer defaecation and were generally satisfied with their therapy. The main device-related adverse event was the requirement to undertake reprogramming (in 52% of subjects with actions following an event). The rates of infection (in 6% of subjects) and surgical revision (in 10% of subjects) were in agreement with literature reports.

CONCLUSION

This study confirms the clinical effectiveness, safety and positive effect of SNM on QoL as well as high patient satisfaction for the treatment of FI in real-life.

Non-dynamic graciloplasty is an effective treatment for patients with passive fecal incontinence

BACKGROUND

Fecal incontinence is a multifactorial problem and its etiology is complex. Various therapies are available and different success rates have been described. The aim of this study was to assess the effectiveness and safety of non-dynamic graciloplasty in patients with passive fecal incontinence.

METHODS

We retrospectively studied charts of patients with fecal incontinence treated with graciloplasty at our institution from November 2015 until June 2018. Patients were included according to the following criteria: (1) presence of predominantly passive fecal incontinence and (2) presence of a lax perineal body. Primary outcome was the effectiveness, defined as a significant reduction or absence of the complaints of passive fecal incontinence at 3, 6 and 12 months after surgery. Second, we studied the safety of the procedure evaluating the complications within 30 days after surgery.

RESULTS

Thirty-one patients met the inclusion criteria. Twenty-six of them, in addition to passive incontinence as the main symptom, had some degree of fecal urgency. The median age at the first visit to the outpatient clinic was 64.0 years (IQR 52-68). Most patients were female (n = 29, 94%). At 3 months after graciloplasty, 71% (22 of 31) of patients were successfully treated for their passive fecal incontinence. At 6 months, the success rate of the graciloplasty increased to 77%. At 12 months among the patients who were still seen in the clinic, the success rate was 58% (18/31). Two patients cancelled follow-up visits after 3 months, because of failure to control symptoms in 1 case. After 6 months, 9 patients were given the choice to do telephone follow-up only. Of these 11 patients without in-person follow-up, 10 were contacted 1 year after surgery and in 7 of them, the graciloplasty was effective in controlling their passive fecal incontinence for an overall success rate of 80% (25/31). Of the 26 patients with mixed passive and urge incontinence, 6 (23%) still complained of urge incontinence at 1 year. Of these patients with persistent urge incontinence, 6 underwent sacral nerve stimulation which was successful in 4. Two serious complications occurred within 30 days. A rectal perforation requiring temporary colostomy and a recto-vaginal fistula which was successfully repaired.

CONCLUSION

Non-dynamic graciloplasty is an effective treatment for passive fecal incontinence. Differentiation based on subtypes of fecal incontinence might be important for a pattern-specific approach to treatment. More research is necessary to determine the right indications for more invasive treatments of fecal incontinence.

Evaluation of progression from first to second stage sacral neuromodulation and unplanned device removal

OBJECTIVE

Sacral neuromodulation (SNM) is an advanced treatment option for patients with refractory overactive bladder (OAB) symptoms, urinary retention, and bowel disorders; it is usually performed in 2 separate procedures. This study aims to determine a cohort's progression rate from stage 1 to 2 and predict factors for progression and unplanned device removal or revision.

MATERIAL AND METHODS

A retrospective review was conducted in patients who underwent SNM at a single institution between June 2012 and May 2019. Progression rates from stage 1 to 2, patient characteristics, and indications for unplanned SNM removal or revision were recorded. Chi-square, Mann-Whitney U, and Fisher's exact tests were used for data analysis.

RESULTS

A total of 128 patients underwent SNM for 1 or more of the following diagnoses: OAB (n=103), urinary retention (n=15), neurogenic bladder dysfunction (n=4), fecal incontinence (n=2), and constipation (n=4). The progression rate to stage 2 was 92.2% (118/128). Patients who failed to progress to stage 2 had additional diagnoses other than OAB, such as urinary retention or bowel disorders (p=0.007). Fifteen patients (12.7%) required SNM removal or revision within 4 years of surgery. Among these patients, the body mass index was significantly lower (p=0.036).

CONCLUSION

Most patients (92.2%) progressed to stage 2. Patients with only OAB symptoms had a higher progression rate to stage 2. Single full-stage procedures may be considered in select patients to reduce morbidity, time, and costs.

Effect of sacral neuromodulation on bowel dysfunction in patients with neurogenic bladder

AIM

The aim of this retrospective study was to evaluate the clinical effect of sacral neuromodulation (SNM) on bowel dysfunction in patients with neurogenic bladder using the neurogenic bowel dysfunction (NBD) score.

METHOD

Between July 2012 and July 2019, 41 patients with both neurogenic bladder and bowel dysfunction underwent permanent SNM implantation. The NBD score was used to evaluate the bowel symptoms before the testing phase and at follow-up. The first follow-up was at the time of discharge after permanent implantation. The second follow-up was conducted by telephone after discharge.

RESULTS

The mean NBD score before the testing phase was 11.0 ± 5.83, whilst it significantly decreased to 5.2 ± 5.32 (n = 41, P < 0.05) at the first follow-up (32 ± 3.9 days). Before the testing phase, there were 9 patients with very minor NBD, 10 with minor NBD, 13 with moderate NBD and 9 with severe NBD. At the first follow-up, there were 26 patients with very minor NBD, 7 with minor NBD, 4 with moderate NBD and 4 with severe NBD (P < 0.05). Twenty-six patients were interviewed in the long-term follow-up (34 ± 30.9 months). The NBD score in these 26 patients was 5.6 ± 5.18, which was not significantly different from the NBD score (5.5 ± 5.33) at the first follow-up (n = 26, P > 0.05).

CONCLUSION

SNM facilitates a significant reduction in NBD score in patients with neurogenic bladder and bowel dysfunction. The improvement in NBD symptoms can also be used as a future indicator to determine the clinical efficacy of permanent SNM implantation in the treatment of neurogenic bladder.

Sacral Neuromodulation for Lower Urinary Tract and Bowel Dysfunction in Animal Models: A Systematic Review With Focus on Stimulation Parameter Selection

OBJECTIVE

Conventional sacral neuromodulation (SNM) has shown to be an effective treatment for lower urinary tract and bowel dysfunction, but improvements of clinical outcome are still feasible. Currently, in preclinical research, new stimulation parameters are being investigated to achieve better and longer effects. This systematic review summarizes the status of SNM stimulation parameters and its effect on urinary tract and bowel dysfunction in preclinical research.

MATERIALS AND METHODS

The literature search was conducted using three databases: Ovid (Medline, Embase) and PubMed. Articles were included if they reported on stimulation parameters in animal studies for lower urinary tract or bowel dysfunction as a primary outcome. Methodological quality assessment was performed using the SYRCLE Risk of Bias (RoB) tool for animal studies.

RESULTS

Twenty-two articles were eligible for this systematic review and various aspects of stimulation parameters were included: frequency, intensity, pulse width, stimulation signal, timing of stimulation, and unilateral vs. bilateral stimulation. In general, all experimental studies reported an acute effect of SNM on urinary tract or bowel dysfunction, whereas at the same time, various stimulation settings were used.

CONCLUSIONS

The results of this systematic review indicate that SNM has a positive therapeutic effect on lower urinary tract and bowel dysfunction. Using low-frequency-SNM, high-frequency-SNM, bilateral SNM, and higher pulse widths showed beneficial effects on storage and evacuation dysfunction in animal studies. An increased variability of stimulation parameters may serve as a basis for future improvement of the effect of SNM in patients suffering from urinary tract or bowel dysfunction.

Improvements in Self-Reported Depression Following Treatment of Fecal Incontinence with Sacral Neuromodulation

OBJECTIVE

To evaluate changes in self-reported depression after treatment of fecal incontinence (FI) with sacral neuromodulation.

MATERIALS AND METHODS

This is a subanalysis of data collected from March 2016 to October 2017 for an Institutional Review Board-approved retrospective cohort study. Demographic information, medical history, psychiatric comorbidities, and the Patient-Reported Outcomes Measurement Information System item bank t-scores were extracted from the electronic medical record. The differences in t-scores were compared with a two-sided paired t-test, and a p value <0.05 was considered statistically significant.

RESULTS

Of the cohort (n = 24), most were Caucasian (88%), female (92%), nonsmokers (92%). Median age was 63.5 years (interquartile range 57.5-71.0 years) and median body mass index was 27.7 kg/m² (range 18.3-42.9 kg/m² ). A significant decrease in mean depression t-scores occurred after implantation of a sacral neuromodulation device, -4.5 (95% confidence interval [CI]: -8.7, -0.2, p = 0.04). Self-reported pain interference (p = 0.37) and physical function (p = 0.47) scores were similar following implantation. Individuals with comorbid anxiety reported the greatest improvement in depression (-6.5, 95% CI: -11.8, -1.1, p = 0.02).

CONCLUSIONS

Treatment of FI with sacral neuromodulation was associated with improvement in self-reported depression with the greatest improvement in those with anxiety. Further prospective research is needed to corroborate these findings.

A novel combined anorectal biofeedback and percutaneous tibial nerve stimulation protocol for treating fecal incontinence

BACKGROUND/AIMS

Fecal incontinence (FI) is a common, debilitating condition that causes major impact on quality of life for those affected. Non-surgical treatment options include anorectal biofeedback therapy (BF) and percutaneous tibial nerve stimulation (PTNS), usually performed separately. The aims of the current study were to determine the feasibility, tolerability, safety, and efficacy of performing a combined BF and PTNS treatment protocol.

METHODS

Female patients with urge FI were offered a novel pilot program combining BF with PTNS. The treatment protocol consisted of 13 weekly sessions: an educational session, followed by 5 combined BF and PTNS sessions, 6 PTNS and a final combined session. Anorectal physiology and clinical outcomes were assessed throughout the program. For efficacy, patients were compared with BF only historical FI patients matched for age, parity, and severity of symptoms.

RESULTS

A total of 12/13 (93%) patients completed the full program. Overall attendance rate was 93% (157/169 sessions). Patient comfort score with treatment was rated high at 9.8/10 (SD 0.7) for PTNS and 8.6/10 (SD 1.7) for the BF component. No major side effects were reported. A reduction of at least 50% in FI episodes/week was achieved by 58% of patients by visit 6, and 92% by visit 13. No physiology changes were evident immediately following PTNS compared with before, but pressure during sustained anal squeeze improved by the end of the treatment course. Comparing outcomes with historical matched controls, reductions in weekly FI episodes were more pronounced in the BF only group at visit 6, but not week 13.

CONCLUSIONS

In this pilot study, concurrent PTNS and anorectal biofeedback therapy has been shown to be feasible, comfortable, and low risk. The combined protocol is likely to be an effective treatment for FI, but future research could focus on optimizing patient selection.

Sacral nerve stimulation increases gastric accommodation in rats: a spinal afferent and vagal efferent pathway

Impaired gastric accommodation (GA) has been frequently reported in various gastrointestinal diseases. No standard treatment strategy is available for treating impaired GA. We explored the possible effect of sacral nerve stimulation (SNS) on GA and discovered a spinal afferent and vagal efferent mechanism in rats. Sprague-Dawley rats (450-500 g) with a chronically implanted gastric cannula and ECG electrodes were studied in a series of sessions to study: 1) the effects of SNS with different parameters on gastric tone, compliance, and accommodation using a barostat device; two sets of parameters were tested as follows: parameter 1) 5 Hz, 500 µs, 10 s on 90 s off; 90% motor threshold and parameter 2) same as parameter 1 but 25 Hz; 2) the involvement of spinal afferent pathway via detecting c-fos immunoreactive (IR) cells in the nucleus of the solitary tract (NTS) of the brain; 3) the involvement of vagal efferent activity via the spectral analysis of heart rate variability derived from the ECG; and 4) the nitrergic mechanism, N^ω-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase (NOS) inhibitor, was given before SNS at 5 Hz. Compared with sham-SNS: 1) SNS at 5 Hz inhibited gastric tone and increased gastric compliance and GA. No difference was noted between the stimulation frequencies of 5 and 25 Hz. 2) SNS increased the expression of c-fos in the NTS. 3) SNS increased cardiac vagal efferent activity and decreased the sympathovagal ratio. 4) l-NAME blocked the relaxation effect of SNS. In conclusion, SNS with certain parameters relaxes gastric fundus and improves gastric accommodation mediated via a spinal afferent and vagal efferent pathway.NEW & NOTEWORTHY Currently, there is no adequate medical therapy for impaired gastric accommodation, since medications that relax the fundus often impair antral peristalsis and thus further delay gastric emptying that is commonly seen in patients with functional dyspepsia or gastroparesis. The advantage of the potential sacral nerve stimulation therapy is that it improves gastric accommodation by enhancing vagal activity, and the enhanced vagal activity would lead to enhanced antral peristalsis rather than inhibiting it.