Sacral nerve stimulation for faecal incontinence: response rate, satisfaction and the value of preoperative investigation in patient selection

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.

Current Position of Sacral Neuromodulation in Treatment of Fecal Incontinence

Fecal incontinence (FI) is defined as uncontrolled passage of feces or gas for at least 1-month duration in an individual who previously had control. FI is a common and debilitating condition affecting many individuals. Continence depends on complex relationships between anal sphincters, rectal curvatures, rectoanal sensation, rectal compliance, stool consistency, and neurologic function. Factors, such as pregnancy, chronic diarrhea, diabetes mellitus, previous anorectal surgery, urinary incontinence, smoking, obesity, limited physical activity, white race, and neurologic disease, are known to be the risk factors for FI. Conservative/medical management including biofeedback are recognized as the first-line treatment of the FI. Those who are suitable for surgical intervention and who have failed conservative management, sacral nerve stimulation (SNS) has emerged as the treatment of choice in many patients. The surgical technique involves placement of a tined lead with four electrodes through the S3 sacral foramen. The lead is attached to a battery, which acts as a pulse generator, and is placed under the patient's skin in the lower lumbar region. The use of SNS in the treatment of FI has increased over the years and the beneficial effects of this treatment have been substantiated by multiple studies. This review describes SNS as a modality of treatment for FI and its position in the current medical diaspora in patients with FI.

LONG-TERM EVOLUTION OF CONTINENCE AND QUALITY OF LIFE AFTER SPHINCTEROPLASTY FOR OBSTETRIC FECAL INCONTINENCE

Purpose

This study was performed to evaluate the long-term evolution of continence and patient’s quality of life after surgical treatment for obstetric fecal incontinence.

Methods

A prospective longitudinal study was conducted including consecutive patients who underwent sphincteroplasty for severe obstetric fecal incontinence. The first phase analyzed changes in continence and impact on quality of life. The second phase studied the long-term evolution reevaluating the same group of patients 6 years later. Degree of fecal incontinence was calculated using the Cleveland Clinic Score (CCS). Quality of life assessment was carried out with the Fecal Incontinence Quality of Life scale.

Results

Thirty-five patients with median age of 55 years (range, 28 to 73 years) completed the study. Phase 1 results: after a postoperative follow-up of 30 months (4 to 132 months), CCS had improved significantly from a preoperative of 15.7 ± 3.1 to 6.1 ± 5.0 (P < 0.001). Phase 2 results: median follow-up in phase 2 was 110 months (76 to 204 months). The CCS lowered to 8.4 ± 4.9 (P = 0.04). There were no significant differences between phases 1 and 2 in terms of quality of life; lifestyle (3.47 ± 0.75 vs. 3.16 ± 1.04), coping/behavior (3.13 ± 0.83 vs. 2.80 ± 1.09), depression/self-perception (3.65 ± 0.80 vs. 3.32 ± 0.98), and embarrassment (3.32 ± 0.90 vs. 3.12 ± 1.00).

Conclusion

Sphincteroplasty offers good short-medium term outcomes in continence and quality of life for obstetric fecal incontinence treatment. Functional clinical results deteriorate over time but did not impact on patients’ quality of life.

Adverse events of sacral neuromodulation for fecal incontinence reported to the federal drug administration

AIM: To investigate the nature and severity of AE related to sacral neurostimulation (SNS).

METHODS: Based on Pubmed and Embase searches, we identified published trials and case series of SNS for fecal incontinence (FI) and extracted data on adverse events, requiring an active intervention. Those problems were operationally defined as infection, device removal explant or need for lead and/or generator replacement. In addition, we analyzed the Manufacturer and User Device Experience registry of the Federal Drug Administration for the months of August - October of 2015. Events were included if the report specifically mentioned gastrointestinal (GI), bowel and FI as indication and if the narrative did not focus on bladder symptoms. The classification, reporter, the date of the recorded complaint, time between initial implant and report, the type of AE, steps taken and outcome were extracted from the report. In cases of device removal or replacement, we looked for confirmatory comments by healthcare providers or the manufacturer.

RESULTS: Published studies reported adverse events and reoperation rates for 1954 patients, followed for 27 (1-117) mo. Reoperation rates were 18.6% (14.2-23.9) with device explants accounting for 10.0% (7.8-12.7) of secondary surgeries; rates of device replacement or explant or pocket site and electrode revisions increased with longer follow up. During the period examined, the FDA received 1684 reports of AE related to SNS with FI or GI listed as indication. A total of 652 reports met the inclusion criteria, with 52.7% specifically listing FI. Lack or loss of benefit (48.9%), pain or dysesthesia (27.8%) and complication at the generator implantation site (8.7%) were most commonly listed. Complaints led to secondary surgeries in 29.7% of the AE. Reoperations were performed to explant (38.2%) or replace (46.5%) the device or a lead, or revise the generator pocket (14.6%). Conservative management changes mostly involved changes in stimulation parameters (44.5%), which successfully addressed concerns in 35.2% of cases that included information about treatment results.

CONCLUSION: With reoperation rates around 20%, physicians need to fully disclose the high likelihood of complications and secondary interventions and exhaust non-invasive treatments, including transcutaneous stimulation paradigms.

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.

Long-term outcomes of sacral nerve stimulation for faecal incontinence

BACKGROUND

Sacral nerve stimulation (SNS) has proven short- to medium-term effectiveness for the treatment of faecal incontinence (FI); fewer long-term outcomes have been presented and usually in small series. Here, the long-term effectiveness of SNS was evaluated in a large European cohort of patients with a minimum of 5 years' follow-up.

METHODS

Prospectively registered data from patients with FI who had received SNS for at least 5 years from ten European centres were collated by survey. Daily stool diaries, and Cleveland Clinic and St Mark's incontinence scores were evaluated at baseline, after implantation and at the last follow-up. SNS was considered successful when at least 50 per cent symptom improvement was maintained at last follow-up.

RESULTS

A total of 407 patients underwent temporary stimulation, of whom 272 (66·8 per cent) had an impulse generator implanted; 228 (56·0 per cent) were available for long-term follow-up at a median of 84 (i.q.r. 70-113) months. Significant reductions in the number of FI episodes per week (from median 7 to 0·25) and summative symptom scores (median Cleveland Clinic score from 16 to 7, St Mark's score from 19 to 6) were recorded after implantation (all P < 0·001) and maintained in long-term follow-up. In per-protocol analysis, long-term success was maintained in 71·3 per cent of patients and full continence was achieved in 50·0 per cent; respective values based on intention-to-treat analysis were 47·7 and 33·4 per cent. Predictive analyses determined no significant association between pretreatment variables and successful outcomes. Risk of long-term failure correlated with minor symptom score improvement during the temporary test phase.

CONCLUSION

SNS remains an effective treatment for FI in the long term for approximately half of the patients starting therapy.

Resource implications of running a sacral neuromodulation service: a 10-year experience

AIM

In this study we reviewed our 10-year experience of the medium- to long-term success of sacral nerve stimulation (SNS) for faecal incontinence, with particular reference to the resource implications of running such a service.

METHOD

All patients treated with permanent SNS implants for faecal incontinence from 2001 to 2012 were identified from a prospective database. The patients underwent follow up at 3 and 6 months, with annual review thereafter. They were divided into four groups: group 1, patients optimized after two reviews; group 2, patients optimized after further review; group 3, patients who failed to reach a satisfactory state; and group 4, patients who had a good initial result with subsequent failure.

RESULTS

Eighty-five patients underwent permanent SNS with a median follow up of 24 (range: 3-108) months. Group 1 included 30 (35%) patients; group 2 included 27 (32%) patients [median of two (range: 2-6) additional visits]; group 3 included 18 (21%) patients [median of six (range: 3-10) additional visits]; and group 4 included 10 (12%) patients [median interval to failure was 54 (range: 24-84) months]. Twenty-seven per cent of our patients had an unsatisfactory outcome and the cost of follow up for these patients was £36,854 (48.7% of the total follow-up costs).

CONCLUSION

The study highlights the significant resource implications of running an SNS service with a large proportion of patients requiring prolonged review, with more than one-quarter having an unsatisfactory outcome at a substantial cost.

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.

Sacral nerve stimulation for the treatment of severe faecal incontinence: results after 10 years experience

INTRODUCTION

The objective of this study is to report our experience with sacral nerve stimulation for the treatment of severe faecal incontinence after the first 10 years with this technique.

MATERIAL AND METHODS

Between 2001 and 2011, 49 patients with severe faecal incontinence underwent sacral nerve stimulation. Anorectal manometry, endoanal ultrasound and pudendal nerve latency were performed. Bowel habit diary, severity of faecal incontinence and quality of life scales were evaluated preoperatively and at the end of follow-up.

RESULTS

Morbidity occurred in a third of patients, mostly minor. Four definitive devices were explanted. With a median follow-up of 37 months, severity of faecal incontinence, urge and incontinence episodes significantly improved at the end of follow-up. Patients' subgroup with major follow-up of 5 years significantly improved the severity of faecal incontinence but not the parameters of the bowel habit diary. Quality of life showed no significant improvement. Descriptive data in patients with sphincter defects did not show worse results than with sphincter integrity.

CONCLUSION

Sacral nerve stimulation is a safe technique for severe faecal incontinence with good functional medium-term results. In the long term, severity of the faecal incontinence also improves but studies with larger sample are necessary to show if other clinical parameters and the quality of life support this information. Preliminary results in patients with sphincter defects suggest that this technique could be effective in this group but future studies will have to confirm these findings.

Current management of fecal incontinence: Choosing amongst treatment options to optimize outcomes

The severity of fecal incontinence widely varies and can have dramatic devastating impacts on a person’s life. Fecal incontinence is common, though it is often under-reported by patients. In addition to standard treatment options, new treatments have been developed during the past decade to attempt to effectively treat fecal incontinence with minimal morbidity. Non-operative treatments include dietary modifications, medications, and biofeedback therapy. Currently used surgical treatments include repair (sphincteroplasty), stimulation (sacral nerve stimulation or posterior tibial nerve stimulation), replacement (artificial bowel sphincter or muscle transposition) and diversion (stoma formation). Newer augmentation treatments such as radiofrequency energy delivery and injectable materials, are minimally invasive tools that may be good options before proceeding to surgery in some patients with mild fecal incontinence. In general, more invasive surgical treatments are now reserved for moderate to severe fecal incontinence. Functional and quality of life related outcomes, as well as potential complications of the treatment must be considered and the treatment of fecal incontinence must be individualized to the patient. General indications, techniques, and outcomes profiles for the various treatments of fecal incontinence are discussed in detail. Choosing the most effective treatment for the individual patient is essential to achieve optimal outcomes in the treatment of fecal incontinence.

Systematic review of the clinical effectiveness of neuromodulation in the treatment of faecal incontinence

BACKGROUND

Over the past 18 years neuromodulation therapies have gained support as treatments for faecal incontinence (FI); sacral nerve stimulation (SNS) is the most established of these. A systematic review was performed of current evidence regarding the clinical effectiveness of neuromodulation treatments for FI.

METHODS

The review adhered to the PRISMA framework. A comprehensive search of the literature included PubMed, MEDLINE, Embase and Evidence-Based Medicine Reviews. Methodological quality assessment and data extraction were completed in a systematic fashion.

RESULTS

For SNS, 321 citations were identified initially, of which 61 studies were eligible for inclusion. Of studies on other neuromodulation techniques, 11 were eligible for review: seven on percutaneous tibial nerve stimulation (PTNS) and four on transcutaneous tibial nerve stimulation (TTNS). On intention-to-treat, the median (range) success rates for SNS were 63 (33-66), 58 (52-81) and 54 (50-58) per cent in the short, medium and long terms respectively. The success rate for PTNS was 59 per cent at the longest reported follow-up of 12 months. SNS, PTNS and TTNS techniques also resulted in improvements in Cleveland Clinic Incontinence Score and quality-of-life measures. Despite significant use of neuromodulation in treatment of FI, there is still no consensus on outcome reporting in terms of measures used, aetiologies assessed, length of follow-up or assessment standards.

CONCLUSION

Emerging data for SNS suggest maintenance of its initial therapeutic effect into the long term. The clinical effectiveness of PTNS is comparable to that of SNS at 12 months, although there is no evidence to support its continued effectiveness after this period. PTNS may be a useful treatment before SNS. The clinical effectiveness of TTNS is still uncertain owing to the paucity of available evidence. A consensus to standardize the use of outcome measures is recommended in order that further reports can be compared meaningfully.

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

BACKGROUND

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

OBJECTIVE

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

DATA SOURCE

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

STUDY SELECTION

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Efficacy of sacral nerve stimulation for the treatment of fecal incontinence

BACKGROUND

Sacral nerve stimulation has been shown to be an effective treatment for fecal incontinence and early studies reported success rates of 67% to 100%. However, "success" has been arbitrarily set at a 50% reduction in symptoms, and data are rarely reported with "intention to treat."

OBJECTIVE

This study aimed to assess the true efficacy of sacral nerve stimulation for fecal incontinence compared with the published literature.

DESIGN

This prospective 5-year study was conducted to assess 50 patients with fecal incontinence treated with sacral nerve stimulation. All analyses were performed on an intention-to-treat basis.

SETTINGS

This study took place in a single tertiary referral colorectal department.

PATIENTS

Fifty consecutive patients with fecal incontinence refractory to conservative management were included in the study.

INTERVENTIONS

The interventions performed were temporary evaluation with or without permanent sacral nerve stimulation.

MAIN OUTCOME MEASURES

: Primary outcome measures were 1) attainment of continence, 2) reduction in fecal incontinence episodes, 3) improvement in Cleveland Clinic Fecal Incontinence scores, and 4) improvement in the ability to defer defecation.

RESULTS

Thirteen patients (26%) did not respond at the temporary evaluation stage or were dissatisfied with the result. Ten further patients (20%) did not achieve a 50% reduction in symptoms following permanent implantation. The median follow-up was 17 months (range, 2-55), at which time 27 patients (54%) experienced a 50% or more reduction in symptoms, including 13 (26%) who achieved apparent continence. Median fecal incontinence episodes per fortnight reduced from 14 (range, 0-53) to 2 (range, 0-20; P < .0001). Median Cleveland Clinic Fecal Incontinence scores reduced from 15 (range, 3-20) to 8 (range, 0-17; P < .0001). The ability to defer defecation improved significantly (P < .0001). These results compare favorably with the published literature.

LIMITATIONS

Quality of life was not assessed.

CONCLUSIONS

This study demonstrates that sacral nerve stimulation can be an effective treatment for patients with fecal incontinence; however, when analyzed by intention to treat, the symptoms of fecal incontinence continue in the majority (74%) of patients.

Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: results of trial stimulation in 200 patients

AIM

Sacral nerve stimulation (SNS) has a place in the treatment algorithm for faecal incontinence (FI). However, after implantation, 15-30% of patients with FI fail to respond for unknown reasons. We investigated the effect of SNS on continence and quality of life (QOL) and tried to identify specific predictive factors of the success of permanent SNS in the treatment of FI.

METHOD

Two hundred consecutive patients (six men; median age = 60; range 16-81) underwent permanent implantation for FI. The severity of FI was evaluated by the Cleveland Clinic Score. Quality of life was evaluated by the French version of the American Society of Colon and Rectal Surgeons (ASCRS) quality of life questionnaire (FIQL). All patients underwent a preoperative evaluation. After permanent implantation, severity and QOL scores were reevaluated after six and 12 months and then once a year.

RESULTS

The severity scores were significantly reduced during SNS (P = 0.001). QOL improved in all domains. At the 6-month follow-up, the clinical outcome of the permanent implant was not affected by age, gender, duration of symptoms, QOL, main causes of FI, anorectal manometry or endoanal ultrasound results. Only loose stool consistency (P = 0.01), persistent FI even though diarrhoea was controlled by medical treatment (P = 0.004), and low stimulation intensity (P = 0.02) were associated with improved short-term outcomes. Multivariate analysis confirmed that loose stool consistency and low stimulation intensity were related to a favourable outcome.

CONCLUSION

Stool consistency and low stimulation intensity have been identified as predictive factors for the short-term outcome of SNS.

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.

Sphincteroplasty for fecal incontinence in the era of sacral nerve modulation

The role of sphincteroplasty in the treatment of patients with fecal incontinence due to anal sphincter defects has been questioned because the success rate declines in the long-term. A new emerging treatment for fecal incontinence, sacral nerve stimulation, has been shown to be effective in these patients. However, the success rate of sphincteroplasty may depend of several patient-related and surgical-related factors and the outcome from sphincteroplasty has been evaluated differently (with qualitative data) from that after sacral nerve stimulation (quantitative data using scoring systems and quality of life). Furthermore, the data available so far on the long-term success rate after sacral nerve modulation do not differ substantially from those after sphincteroplasty. The actual data do not support the replacement of sphincteroplasty with sacral nerve stimulation in patients with fecal incontinence secondary to sphincter defects.

Sacral nerve stimulation for fecal incontinence: What has been achieved: Current status

INTRODUCTION: The indications for sacral nerve stimulation (SNS) for fecal incontinence expanded during the last decade. This report aims to analyze the clinical outcome of the current pragmatic use of sacral nerve stimulation in the treatment of fecal incontinence caused by various pathophysiological conditions. Secondly it intends to explore the most recent use of SNS in patients presenting with sphincteric lesions. METHOD: The literature was searched using Medline and Cochrane databases. The search was limited to publications in English. For the analysis, studies with less than 25 patients were excluded. For the presentation of SNS in patients with sphincter defects, all papers were included. RESULTS: Thirteen publications were included in the analysis of clinical outcome of SNS. Ten papers were identified reporting about the application of SNS in patients presenting with a morphological sphincter lesion. The most common outcome measures of clinical efficacy were frequency of incontinence and Cleveland Clinic Incontinence Score. All studies demonstrated a highly improved function, in all outcome measures used. The improvement was significant. The results are reproducible. Also in patients with sphincteric gaps ranging form 17 to 180 degree SNS was clinical efficient. The size of the lesion had not impact on the outcome. CONCLUSION: Sacral spinal nerve stimulation has evolved to become a clinical efficient therapy applicable in a wide spectrum of causes leading to fecal incontinence. It is now considered to be an essential part of the current surgical treatment algorithm for fecal incontinence.