Sacral nerve stimulation for the treatment of faecal incontinence related to dysfunction of the internal anal sphincter

Long-term Outcomes of Sacral Nerve Stimulation on the Treatment of Fecal Incontinence: A Systematic Review

INTRODUCTION

Sacral nerve stimulation (SNS) has now been used as a treatment for fecal incontinence (FI) for >20 years. The aim of this systematic review was to determine the long-term efficacy of SNS on the treatment of FI.

MATERIALS AND METHODS

A comprehensive search of the MEDLINE, Embase, and Cochrane Central data bases was performed to find publications, excluding case reports, reporting outcomes of SNS treatment for FI in adults with ≥36 months of follow-up. Bias was assessed using the Risk of Bias in Non-randomized Studies-of Interventions tool. Data were summarized per reported FI-related outcomes for symptom severity and quality of life.

RESULTS

In total, 3326 publications were identified, and 36 studies containing 3770 subjects were included. All studies had a serious risk of bias. Success was variably defined by each publication and ranged from 59.4% to 87.5% for per-protocol analyses and 20.9% to 87.5% for intention-to-treat analyses. All studies reporting bowel diary data, St Mark's scores, and Cleveland Clinic Incontinence Scores indicated significant improvement with SNS treatment in the long term. Studies that evaluated quality-of-life outcomes also all showed improvements in quality of life as measured by the Fecal Incontinence Quality of Life Scale. The aggregate revision rate was 35.2%, and the explantation rate was 19.7%.

CONCLUSIONS

Improvements in objective and subjective outcomes at ≥36 months support using SNS for the long-term treatment of FI. Interpretation of these data is limited by a lack of comparative trials and heterogeneity of the included studies.

The role of percutaneous tibial nerve stimulation (PTNS) in the treatment of chronic anal fissure: a systematic review

PURPOSE

This study was designed to summarize the current evidence regarding the role of percutaneous tibial nerve stimulation (PTNS) in the treatment of chronic anal fissure (CAF).

METHODS

The present systematic review of the literature was conducted on the basis of the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. The primary endpoint of our study was the CAF recurrence rate. Quality assessment was based on the RoB 2 tool and the Case Series Quality Checklist.

RESULTS

Overall, 5 studies and 102 patients were included. A considerably heterogeneity in the neuromodulation technique and setting was identified. The pooled recurrence rate was estimated at the level of 19% (16/84). Post-interventional pain and Wexner scores were considerably reduced. The 2-month healing rate was 72% (18/25), whereas 73.6% of patients were symptom-free at 6 months.

CONCLUSIONS

PTNS is an effective alternative for the non-operative management of CAF. Due to several limitations further larger and higher quality studies are required.

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.

Middle-term Outcomes of Gatekeeper Implantation for Fecal Incontinence

BACKGROUND

Intersphincteric injectable bulking agents are one of the current treatment options for fecal incontinence, failing behavioral and medical therapy. Gatekeeper showed promising short-term results, but long-term outcomes are unknown.

OBJECTIVE

The purpose of this study was to clinically evaluate a prospective cohort of fecal incontinence patients up to 36 months after implantation of Gatekeeper.

DESIGN

This was a prospective clinical study.

SETTINGS

The study was conducted at a large university tertiary care hospital.

PATIENTS

Consecutive female patients were eligible if fecal incontinence onset was ≥6 months before the first visit and symptoms were refractory to standard conservative measures.

INTERVENTIONS

All of the patients underwent implantation of 4 or 6 Gatekeeper prostheses. Three-dimensional endoanal ultrasonography and high-resolution anorectal manometry were performed preoperatively and postoperatively at 2 and 3 months after implantation.

MAIN OUTCOME MEASURES

The Cleveland Clinic Fecal Incontinence score was calculated at baseline and 1, 3, 12, 24, and 36 months postoperatively.

RESULTS

Twenty patients (all women; median age, 59 y) were enrolled, and all implants were uneventful. Postoperative endoanal ultrasonography showed normal prosthesis localization in 16 patients (80%). At manometry, mean anal resting pressure significantly improved (57.8 ± 7.5 mm Hg; p = 0.0004). Mean preoperative Cleveland Clinic Fecal Incontinence score was 12.4 ± 1.8, with significant improvements initially documented at 3 months (4.9 ± 1.5; p < 0.0001) and sustained up to 36 months (4.9 ± 1.7; p < 0.0001). Patients receiving only 4 (compared with 6) prostheses and those experiencing pudendal neuropathy (compared with those who did not) showed significantly higher Cleveland Clinic Fecal Incontinence score values in the middle term.

LIMITATIONS

The study was limited by its small sample size and absence of quality-of-life data.

CONCLUSIONS

Initial improvements after Gatekeeper implantation for fecal incontinence are sustained in the middle term. Accurate preoperative evaluation of coexistent clinical conditions that may negatively affect outcomes is recommended for patient selection. See Video Abstract at http://links.lww.com/DCR/B109. RESULTADOS A MEDIANO PLAZO EN LA IMPLANTACIÓN DE GATEKEEPER PARA LA INCONTINENCIA FECAL: Los agentes de volumen inyectables interesfintéricos, son opciones actuales de tratamiento para la incontinencia fecal, ante fallas de terapias conductuales y médicas. Gatekeeper mostró resultados prometedores a corto plazo, pero resultados a largo plazo aún son desconocidos.Evaluar clínicamente una cohorte prospectiva de pacientes con incontinencia fecal, hasta 36 meses después de la implantación de Gatekeeper.Estudio clínico prospectivo.El estudio se realizó en un gran hospital universitario de atención terciaria.Fueron elegibles pacientes femeninas consecutivas, si el inicio de la incontinencia fecal, fue al menos 6 meses antes de la primera visita, y que los síntomas fueron refractarios a las medidas conservadoras estandarizadas.Todas las pacientes fueron sometidas a implantación de 4 o 6 prótesis Gatekeeper. Se realizó ecografía endoanal de 3D y manometría anorrectal de alta resolución, antes de la implantación y después a los 2 y 3 meses.Se calculó el puntaje de incontinencia fecal de la Cleveland Clinic al inicio, y a los 1, 3, 12, 24 y 36 meses después de la operación.Se inscribieron veinte pacientes (todas mujeres; con edad media de 59 años), y todos los implantes transcurrieron sin incidentes. La ecografía endoanal postoperatoria, mostró localización normal de la prótesis en 16 (80%) pacientes. A la manometría, la presión media de reposo anal, mejoró significativamente (57.8 ± 7.5 mmHg, p = 0.0004). La puntuación media preoperatoria de la incontinencia fecal de la Cleveland Clinic, fue de 12.35 ± 1.75, con mejoras significativas documentadas inicialmente a los 3 meses (4.9 ± 1.5, p <0.0001) y sostenidas hasta los 36 meses (4.9 ± 1.7, p <0.0001). Los pacientes que recibieron solo 4 prótesis (en comparación con 6) y que padecían neuropatía pudenda (en comparación con aquellas que no la padecían), mostraron valores de puntaje de Incontinencia Fecal de la Clínica Cleveland, significativamente más altos en el mediano plazo.El tamaño pequeño de la muestra y la ausencia de datos en calidad de vida.Las mejoras iniciales después de la implantación de Gatekeeper para la incontinencia fecal, se mantienen en el mediano plazo. Para la selección de pacientes, se recomienda una precisa evaluación preoperatoria de las condiciones clínicas coexistentes, que puedan afectar negativamente los resultados. Consulte Video Resumen en http://links.lww.com/DCR/B109.

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.

Is-it possible to distinguish irritable bowel syndrome with constipation from functional constipation?

BACKGROUND

The Rome III criteria classify patients complaining of constipation into two main groups: patients with functional constipation (FC) and patients with constipation predominant irritable bowel syndrome (IBS-C). The purpose of this study was to identify differences in the intensity of symptoms and total and segmental colonic transit time in these two types of patients.

METHODS

We performed a prospective evaluation of 337 outpatients consecutively referred for chronic constipation and classified according to the Rome III criteria as FC or IBS-C. They were asked to report symptom intensity, on a 10-point Likert scale, for diarrhea, constipation, bloating and abdominal pain. Stool form was reported using the Bristol scale, and colonic transit time was measured by using multiple-ingestion single-marker single-film technique. Statistical analysis was completed by a discriminant analysis.

RESULTS

Female gender and obstructed defecation was more frequent in IBS-C patients than in FC patients. IBS-C patients reported greater symptom intensity than FC patients, but stool form, and total and segmental colonic transit time were not different between the two groups. Multivariate logistic regression showed that only two parameters, bloating and abdominal pain, were related to the IBS-C or to the FC phenotype, and discriminant analysis showed that these two parameters were sufficient to give a correct classification of 71% of the patients.

CONCLUSIONS

Our study suggests that self-evaluation of abdominal pain and bloating is more helpful than colonic transit time in classifying patient as IBS-C or FC.

Internal anal sphincter: Clinical perspective

OBJECTIVE

To summarise current knowledge of Internal anal sphincter.

BACKGROUND

The internal anal sphincter (IAS) is the involuntary ring of smooth muscle in the anal canal and is the major contributor to the resting pressure in the anus. Structural injury or functional weakness of the muscle results in passive incontinence of faeces and flatus. With advent of new assessment and treatment modalities IAS has become an important topic for surgeons. This review was undertaken to summarise our current knowledge of internal anal sphincter and highlight the areas that need further research.

METHOD

The PubMed database was used to identify relevant studies relating to internal anal sphincter.

RESULTS

The available evidence has been summarised and advantages and limitations highlighted for the different diagnostic and therapeutic techniques.

CONCLUSION

Our understanding of the physiology and pharmacology of IAS has increased greatly in the last three decades. Additionally, there has been a rise in diagnostic and therapeutic techniques specifically targeting the IAS. Although these are promising, future research is required before these can be incorporated into the management algorithm.

Lack of effect of sacral nerve stimulation for incontinence in patients with systemic sclerosis

AIM

Systemic sclerosis (SSc) is a multisystem disorder of unknown aetiology leading to the deposition of excessive connective tissue in the skin, blood vessels and internal organs. Gastrointestinal involvement occurs in 90% of cases and the prevalence of faecal incontinence (FI) is 38%. This study comprises the largest case series assessing the efficacy of sacral nerve stimulation (SNS) treatment for incontinence in this patient group.

METHOD

A retrospective analysis on prospectively collected data was performed on all SSc patients from our two centres who had undergone SNS for FI.

RESULTS

Ten female patients of mean age of 54 (37-72) years had temporary SNS performed. The mean duration of FI was 13 (2-25) years. All had passive FI. Each patient had preprocedure anorectal physiology and endoanal ultrasound examinations documenting internal sphincter atrophy/fragmentation or reduced anal resting pressure. Overall there was no statistically significant difference (P = 0.57) in the total Wexner incontinence scores before (mean 15.1 ± 2.6 SD) and during temporary SNS procedures (mean 13.1 ± 3.6 SD). Two patients with a significant improvement went on to have permanent SNS with only one achieving a favourable outcome at 1 year.

CONCLUSION

This study showed that SNS failed to reduce episodes of leakage in nine out of 10 patients with systemic sclerosis affected with incontinence.

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.

Is sacral neuromodulation here to stay? Clinical outcomes of a new treatment for fecal incontinence

INTRODUCTION

Sacral neuromodulation (SNM) was approved by the FDA for the treatment of fecal incontinence (FI) in 2011, and previous industry-sponsored trials have shown excellent clinical outcomes. The purpose of this study is to examine clinical outcomes of patients treated during our initial experience with SNM.

METHODS

A prospective database of patients treated with SNM for FI by one of three colorectal surgeons at two separate institutions was maintained starting in 2011. Patients showing ≥50% improvement of weekly incontinent episodes during test stimulation were offered permanent implantation of the SNM device. Disease severity was tracked using the Wexner score.

RESULTS

A total of 145 patients received a full system implantation (of 152 who received test stimulation). The median preoperative Wexner score of 14 decreased to 3, 3 months after implantation and persisted to 12 months. At 12 months, 95.2% of patients achieved >50% improvement in Wexner Score and 67.6% achieved >75% improvement. The most common adverse event was infection (3.4%). Three patients (2.1%) required lead revision.

CONCLUSIONS

SNM is a safe and effective therapy for the treatment of FI. Postoperative patient surveillance is important, as many patients require programming changes, and some will require a lead revision over time.

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.

Current status: new technologies for the treatment of patients with fecal incontinence

Fecal incontinence is a frequent and debilitating condition that may result from a multitude of different causes. Treatment is often challenging and needs to be individualized. During the last several years, new technologies have been developed, and others are emerging from clinical trials to commercialization. Although their specific roles in the management of fecal incontinence have not yet been completely defined, surgeons have access to them and patients may request them. The purpose of this project is to put into perspective, for both the patient and the practitioner, the relative positions of new and emerging technologies in order to propose a treatment algorithm.

Seven-year follow-up after anterior sphincter reconstruction for faecal incontinence

PURPOSE

The aim was to evaluate the effects of anterior sphincter repair on faecal incontinence and quality of life.

PATIENTS AND METHODS

Fifty-six patients who underwent anterior anal sphincteroplasty between January 2003 and December 2005 were asked to complete questionnaires containing the Wexner Incontinence Score (a score of 0 corresponds to full continence and 20 to total incontinence) and Faecal Incontinence Quality of Life Scale preoperatively, in May 2006 (mean follow-up time, 22.8 months) and in August 2011 (mean follow-up time, 89.3 months). Thirty-nine (69.6 %) patients completed the questionnaires before the operation and in 2006, and 36 (64.3 %) in 2011.

RESULTS

The overall severity of faecal incontinence improved in 26 patients (67 %), and quality of life improved in 2006 as a whole, but after a longer follow-up (in 2011), the severity of faecal incontinence was about the same as preoperatively (median, 12.0 months) in all the patients. Among younger patients (≤50 years), the situation was better, but older patients (>50 years) had an even worse situation than before the operation. In the group of younger patients, the preoperative median of the overall incontinence score was 10.5, and in 2011, it was 9.0, while in the group of older patients, the corresponding numbers were 13.0 and 15.0. In 2011, quality of life was still better than preoperatively as a whole, but the results had deteriorated from those in 2006.

CONCLUSIONS

Initially, both overall faecal incontinence and quality of life improved, but younger patients achieved a greater benefit. However, the results deteriorated with a longer follow-up. Operative management should be considered preferably in relatively young subjects as their results are better.

Sacral nerve stimulation in faecal incontinence associated with an anal sphincter lesion: a systematic review

AIM

The long-term results of sphincteroplasty for faecal incontinence due to an anal sphincter lesion have been disappointing. Initially sacral nerve stimulation was used only in faecal incontinence of neurogenic origin but subsequently the indications have been extended to other conditions. The aim of this review was to evaluate sacral nerve stimulation for incontinence in the presence of a sphincter defect.

METHOD

The MEDLINE, Embase and Cochrane Library databases for the period between 1995 and 2011 were searched for studies in English, with no limitations concerning the study size or the length of follow-up. The major endpoints were clinical efficacy, changes in anorectal manometry and quality of life.

RESULTS

Ten reports (119 patients) satisfied the inclusion criteria. The quality of the studies was low (nine were retrospective, one was prospective). All reported a lesion of the external anal and/or internal anal sphincter on endoanal ultrasound. A definitive implant was performed on 106 (89%) of the 119 patients who underwent a peripheral nerve evaluation test. The weighted average number of incontinent episodes per week decreased from 12.1 to 2.3, the weighted average Cleveland Clinic Score decreased from 16.5 to 3.8, and the ability to defer defaecation, when evaluated, increased significantly. The features at anorectal manometry did not change. The quality of life improved significantly in almost all studies.

CONCLUSION

Sacral nerve stimulation could be a therapeutic option for faecal incontinence in patients with an anal sphincter lesion. However, the quality of the published studies is low. A randomized clinical trial comparing sacral nerve stimulation with other classical surgical procedures at long-term follow-up, although beset with difficulties, should be conducted.

Treatment of fecal incontinence - review of observational studies (OS) and randomized controlled trials (RCT) related to injection of bulking agent into peri-anal tissue

PURPOSE: Novel treatments are needed to augment medical therapy for fecal incontinence. METHODS: Medline and Google search (fecal incontinence and injection treatment), English publications. RESULTS: Twenty-two observational studies and 4 randomized controlled trials were identified. OS mostly with limited sample sizes reported promising results. Repeated injection was necessary in some patients. Effect on anal sphincter pressures was highly variable. Significant improvements in the length of anal high-pressure zone, asymmetry index and maximum tolerable rectal volume were suggested. Four randomized controlled trials (n=176) revealed: 1. Short-term benefits from injection of Bioplastique under ultrasound guidance compared with digital guidance; 2. Silicone biomaterial (PTQ) provided some advantages and was safer than carbon-coated beads (Durasphere); 3. PTQ did not demonstrate clinical benefit compared to control injection of saline; 4. There was significant improvement at 6 weeks post injection, but no difference between Bulkamid and Permacol. A 2010 Cochrane review, however, noted that these data were inconclusive due to limited number and methodological weaknesses. CONCLUSION: Further studies are warranted to assess patient-centered outcomes (e.g. adequate relief) in addition to the attenuation of severity of incontinence symptoms in ambulatory patients. In nursing home residents, cost-effectiveness studies combining injection treatment and prompted voiding (to mitigate constraints of immobility and dementia) in preventing peri-anal skin complications deserves to be considered.

Sacral nerve stimulation for faecal incontinence: its role in the treatment algorithm

AIM

Indications for sacral nerve stimulation (SNS) for faecal incontinence have expanded over the last decade. This report aims to determine the clinical outcome of the current use of SNS in the treatment of faecal incontinence. Its objective is also to review the most recent role of SNS in patients with anal sphincter lesions.

METHOD

The literature was searched using Medline and Cochrane databases. The search was restricted to publications in English. For the analysis, studies with <25 patients were excluded. For SNS in patients with sphincter defects, all papers were included.

RESULTS

Thirteen publications on the clinical outcome of SNS were included. Nine papers were identified reporting the application of SNS in patients with a morphological sphincter lesion. The most common outcome measures of clinical efficacy were frequency of incontinence using the Cleveland Clinic Incontinence Score. All studies demonstrated highly improved function across all outcome measures and improvement was statistically significant in all. Outcomes remain stable at long-term follow up. In patients with sphincteric gaps ranging from 17 to 180°, SNS was clinically effective at short-term follow up. The size of the gap appears to have no impact on outcome.

CONCLUSION

SNS has evolved to become a clinical efficient therapy applicable across a wide spectrum of causes of faecal incontinence with reproducible results. SNS can be considered to be an essential part of the current surgical treatment algorithm for faecal incontinence.

The influence of sacral nerve stimulation on anorectal dysfunction

AIM

Sacral nerve stimulation (SNS) has become an established option in the management of defaecatory disorders. There are many data on the end-organ effects of SNS, but limited consensus on its mechanism of action. The objective of this review was to determine the effect of sacral nerve stimulation (SNS) on anorectal function.

METHOD

Systematic literature review of the effect of sacral nerve stimulation (SNS) on anorectal function.

RESULTS

There was significant heterogeneity of data pertaining to the effects of SNS on anorectal function, with no consistent change in physiological measures identified. Most data supported a mixed mechanism of action on anal motor and rectal sensory functioning.

CONCLUSION

To date, conflicting data exist on the mechanism of action of SNS as determined by end-organ changes in anorectal physiology. Nevertheless, the data as they stand best support a mixed mechanism of action on anal motor and rectal sensory functions.

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.

Relief of fecal incontinence by sacral nerve stimulation linked to focal brain activation

OBJECTIVE

This study aimed to test the hypothesis that sacral nerve stimulation affects afferent vagal projections to the central nervous system associated with frontal cortex activation in patients with fecal incontinence.

PATIENTS

Nine women and one man received temporary sacral nerve stimulation with permanent electrodes as a treatment for fecal incontinence.

INTERVENTIONS

We used positron emission tomography to record indices of regional cerebral blood flow before and after 30 minutes of continuous stimulation. We repeated this procedure after 2 weeks of continued stimulation, before and 30 minutes after arrest of the stimulation.

RESULTS

The initial stimulation activated a region of the contralateral frontal cortex that normally is active during focused attention. After 2 weeks of stimulation, this activation had been replaced by activity in parts of the ipsilateral caudate nucleus, a region of the brain thought to be specifically involved in learning and reward processing.

CONCLUSIONS

Sacral nerve stimulation induces changes in cerebral activity consistent with an effect on afferent projections of the vagus. The initial activation of the frontal cortex may reflect focused attention, whereas the subsequent activation of the caudate nucleus may reflect recruitment of mechanisms involved in learning and reward processing. These changes may contribute to the improved continence, which is an acquired result of the stimulation.