Changing paradigm of sacral neuromodulation and external anal sphincter repair for faecal incontinence in specialist centres.

AIM: The aim of this study was to determine whether the paradigm of surgical intervention for faecal incontinence (FI) has changed between 2000 and 2013. METHOD: This was a multi-centre retrospective study of patients who had undergone either sacral neuromodulation (SNM) or delayed sphincter repair or sphincteroplasty (SR) as a primary surgical intervention for FI in five centres in Europe and one in the United States. The flow of patients according to the intervention, sustainability of the treatment at a minimum follow-up of 5 years, complications and requirement for further interventions were recorded. RESULTS: A total of 461 patients (median age 56 years, range 24-90 years, 41 men) had either SNM or SR as an index operation during the study period [SNM 284 (61.6%), SR 177 (38.4%)]. Among SNM patients, there were 169 revisional operations (change of battery and/or lead, re-siting or removal). At the time of last follow-up 203 patients (71.4%) continued to use SNM. Among SR patients, 30 (16.9%) had complications, most notably wound infection (22, 12.4%). During follow-up 32 patients (18.1%) crossed over to SNM. Comparing two 4-year periods (2000-2003 and 2007-2010), the proportion of patients operated on who had a circumferential sphincter defect of less than 90° was 48 (68%) and 45 (46%), respectively (P = 0.03), while those who had SNM as the primary intervention increased from 29% to 89% (P < 0.05). CONCLUSION: The paradigm of surgical intervention for FI has changed with increasing use of SNM.

Reversal of sensory deficit through sacral neuromodulation in an animal model of fecal incontinence.

BACKGROUND: Sacral neuromodulation (SNM) is a treatment option for intractable fecal incontinence. The mechanism of action is unclear, however, increasing evidence for afferent somatosensory effects exists. This study's aim was to elucidate effects of acute SNM on the cerebral cortex in a rodent model of pudendal nerve injury. METHODS: The effects of 14 Hz and 2 Hz SNM on sensory cortical activation were studied. In 32 anesthetized rats, anal canal evoked potentials (EPs) were recorded over the primary somatosensory cortex. Pudendal nerve injury was produced by 1-hour inflation of two intra-pelvic balloons. Four groups were studied: balloon injury, balloon injury plus either 14 Hz or 2 Hz SNM, sham operation. Immunohistochemistry for the neural plasticity marker polysialylated neural cell adhesion molecule (PSA-NCAM) positive cells (numerical density and location) in the somatosensory cortex was performed. KEY RESULTS: Anal EP amplitudes diminished during balloon inflation; 14 Hz SNM restored diminished anal EPs to initial levels and 2 Hz SNM to above initial levels. Evoked potential latencies were prolonged during balloon inflation. The numerical density of PSA-NCAM positive cells increased in the SNM groups, but not in sham or balloon injury without SNM. Stimulated cortices showed clusters of PSA-NCAM positive cells in layers II, IV, and V. Post SNM changes were similar in both SNM groups. CONCLUSIONS & INFERENCES: Sacral neuromodulation augments anal representation in the sensory cortex and restores afferent pathways following injury. PSA-NCAM positive cell density is increased in stimulated cortices and positive cells are clustered in layers II, IV, and V.

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.

A systematic review of sacral nerve stimulation mechanisms in the treatment of fecal incontinence and constipation.

BACKGROUND: Sacral nerve stimulation (SNS) is now well established as a treatment for fecal incontinence (FI) resistant to conservative measures and may also have utility in the management of chronic constipation; however, mechanism of action is not fully understood. End organ effects of SNS have been studied in both clinical and experimental settings, but interpretation is difficult due to the multitude of techniques used and heterogeneity of reported findings. The aim of this study was to systematically review available evidence on the mechanisms of SNS in the treatment of FI and constipation. METHODS: Two systematic reviews of the literature (performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses framework) were performed to identify manuscripts pertaining to (a) clinical and (b) physiological effects of SNS during the management of hindgut dysfunction. KEY RESULTS: The clinical literature search revealed 161 articles, of which 53 were deemed suitable for analysis. The experimental literature search revealed 43 articles, of which nine were deemed suitable for analysis. These studies reported results of investigative techniques examining changes in cortical, gastrointestinal, colonic, rectal, and anal function. CONCLUSIONS & INFERENCES: The initial hypothesis that the mechanism of SNS was primarily peripheral motor neurostimulation is not supported by the majority of recent studies. Due to the large body of evidence demonstrating effects outside of the anorectum, it appears likely that the influence of SNS on anorectal function occurs at a pelvic afferent or central level.

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

INTRODUCTION: Although sacral neuromodulation (SNM) is an established treatment for faecal incontinence, stimulation parameters have been derived empirically and only one frequency (14 Hz) is employed clinically. The aim of this study was to test a range of stimulation frequencies to establish an optimal frequency of SNM for maximum augmentation of anal canal cortical evoked potentials (EPs) in an animal model. METHODS: In female Wistar rats, anal canal EPs were recorded over the primary somatosensory cortex using a flexible multielectrode array, and the effect of SNM was studied. SNM was applied at 0·1-100 Hz and a frequency response curve plotted. The data were fitted to a quadratic equation. RESULTS: The magnitude of potentiation of anal canal EPs caused by SNM depended significantly on stimulation frequency (P < 0·001). The frequency-potentiation relationship was parabolic in form, with a clear optimum at 2 Hz. The SNM must be applied for at least 3 min. The theoretical maximal potentiation predicted by the model was not found to be statistically different to actual data recorded (P = 0·514-0·814). The response depended on stimulation amplitude in an 'all-or-nothing' fashion. EPs were augmented when the SNM intensity was 0·5 times the motor threshold to tail twitch or greater, but values below this intensity failed to affect the EPs. CONCLUSION: The effect of SNM in this animal model is governed principally by frequency, with an optimum of 2 Hz. If animal data can be translated to humans, optimization of SNM frequency may offer a clinically relevant improvement in the efficacy of SNM. Surgical relevance Sacral neuromodulation (SNM) for faecal incontinence currently employs stimulation parameters that have been derived empirically and may not be optimal. This study used an animal model of SNM and focused on its acute effect on anal canal cortical evoked potentials (EPs). It was found that SNM potentiated EPs, with a clear optimum at a frequency of 2 Hz. If this finding is applicable to the mechanism of action of human SNM, this suggests that there may be a clinically relevant improvement by reducing stimulus frequency from its typical value of 14 Hz to 2 Hz.

Randomised controlled trial comparing early home biofeedback physiotherapy with pelvic floor exercises for the treatment of third-degree tears (EBAPT Trial).

OBJECTIVE: To compare early home biofeedback physiotherapy with pelvic floor exercises (PFEs) for the initial management of women sustaining a primary third-degree tear. DESIGN: Single centre, randomised trial. SETTING: National Maternity Hospital, Dublin, Ireland. POPULATION: A total of 120 women sustaining a primary third-degree tear. METHODS: Women were randomised in a one to three ratio: 30 to early postpartum home biofeedback physiotherapy and 90 to PFEs. MAIN OUTCOME MEASURES: Differences in anorectal manometry results, Cleveland Clinic continence scores and Rockwood faecal incontinence quality of life scale scores after 3 months of postpartum treatment. RESULTS: The mean anal resting pressure was 39 ± 13 mmHg in the early biofeedback physiotherapy group and 43 ± 17 mmHg in the PFE group. The mean anal squeeze pressure was 64 ± 17 mmHg in the biofeedback group and 62 ± 23 mmHg in the PFE group. There was no significant difference in anal resting and squeeze pressure values between the groups (P = 0.123 and P = 0.68, respectively). There were no differences in symptom score and quality of life measurements between the groups. CONCLUSIONS: This study demonstrates no added value in using early home biofeedback physiotherapy in the management of women sustaining third-degree tears. Poor compliance may have contributed because women found it difficult to designate time to using biofeedback.

Sacral nerve stimulation increases activation of the primary somatosensory cortex by anal canal stimulation in an experimental model.

BACKGROUND: Sacral and posterior tibial nerve stimulation may be used to treat faecal incontinence; however, the mechanism of action is unknown. The aim of this study was to establish whether sensory activation of the cerebral cortex by anal canal stimulation was increased by peripheral neuromodulation. METHODS: A multielectrode array was positioned over the right primary somatosensory cortex of anaesthetized rats. A brief burst of electrical stimulation was applied to either the left sacral root or the left posterior tibial nerve, and evoked potentials from anal canal stimulation were signal-averaged at intervals over 1 h. At the end of the experiment, the cerebral cortex was removed and probed for polysialylated neural cell adhesion molecule (PSA-NCAM). RESULTS: Sacral nerve root and posterior tibial nerve stimulation significantly increased the peak amplitude of primary cortical evoked potentials by 54.0 and 45.1 per cent respectively. This change persisted throughout the period of observation. The density of PSA-NCAM-positive cells in the somatosensory cortex underlying the electrode array was increased by approximately 50 per cent in the sacral nerve-stimulated group. CONCLUSION: Brief sacral neuromodulation induces profound changes in anal canal representation on the primary somatosensory cortex, providing a plausible hypothesis concerning the mechanism of action of neuromodulation in the treatment of faecal incontinence.

Sacral nerve stimulation for faecal incontinence.

BACKGROUND: Faecal incontinence resulting from obstetric injury is a socially disabling condition with a significant impact on quality of life. Sacral nerve stimulation (SNS) is a relatively new treatment modality, which offers patients a potential for improved continence. METHODS: We reviewed our initial experience of SNS in 14 patients (mean age 54 years, range 30-72) with faecal incontinence from January 2006 to June 2007. Background demographics, past medical and obstetric history, anal manometry, endoanal ultrasound and pudendal nerve studies were recorded on all patients. All patients who had permanent SNS implants inserted had pre and post operative questionnaires consisting of the Wexner Continence Score and the Rockwood and SF-36 Quality of Life Indices. RESULTS: Out of 14 patients, 13 had incontinence related to obstetric injuries while one was related to a cauda equina syndrome. All patients had a test procedure consisting of placement of temporary electrodes and a 2-week trial of external SNS. Ten patients noted a significant improvement in their continence and these 10 patients subsequently had a permanent SNS device implanted with an overall significant improvement in continence (P < 0.001) and quality of life (P < 0.01). There were no immediate postoperative complications and one late failure consisting of a lead fracture, which was replaced successfully. Four (29%) patients did not have a significant benefit from temporary SNS and two of these patients subsequently had a colostomy. CONCLUSIONS: SNS offers improvement in continence and quality of life in patients with faecal incontinence whose only other option might otherwise be a permanent colostomy.

Randomised clinical trial of a laxative alone versus a laxative and a bulking agent after primary repair of obstetric anal sphincter injury.

OBJECTIVE: To compare two postpartum laxative regimens in women who have undergone primary repair of obstetric anal sphincter injury. DESIGN: Randomised controlled trial. SETTING: National Maternity Hospital, Dublin. POPULATION: A total of 147 postpartum women who had sustained anal sphincter injury at vaginal birth. METHODS: Women were randomised to receive either lactulose alone thrice daily for the first three postpartum days followed by sufficient lactulose to maintain a soft stool over the following 10 days (lactulose group, n = 77) or the lactulose regimen combined with a sachet of ispaghula husk daily for the first 10 postpartum days (Fybogel group, n = 70). All patients kept a diary of bowel habit for the first 10 postpartum days and were invited to return for review at 3 months postpartum. MAIN OUTCOME MEASURES: Patient discomfort with first postpartum bowel motion, incidence of postnatal constipation and incontinence and incontinence score in postnatal period. RESULTS: Pain scores were similar in the two treatment groups; but incontinence in the immediate postnatal period was more frequent with the two preparations compared with lactulose alone (32.86% versus 18.18%, P = 0.03). CONCLUSIONS: This study does not support routine prescribing of a stool-bulking agent in addition to a laxative in the immediate postnatal period for women who have sustained anal sphincter injury at vaginal delivery.

A prospective, randomized study comparing the effect of augmented biofeedback with sensory biofeedback alone on fecal incontinence after obstetric trauma.

PURPOSE: This study was designed to compare prospectively the effects of augmented biofeedback with those of sensory biofeedback alone on fecal incontinence and anorectal manometry after obstetric trauma. METHODS: A consecutive cohort of 40 females with impaired fecal continence after obstetric anal sphincter injury were recruited from a dedicated perineal clinic. Patients were randomly assigned to receive either augmented biofeedback or sensory biofeedback alone. All patients were assessed before and after twelve weeks of biofeedback training, using a fecal continence questionnaire and anorectal manometry. RESULTS: Thirty-nine of 40 females recruited completed the study. Continence scores improved in both treatment groups, but the results were better for those who received augmented biofeedback. Anorectal manometry was unchanged by sensory biofeedback, whereas anal resting and squeeze pressures increased with augmented biofeedback. No change in anal vector symmetry was observed in either group. CONCLUSION: Augmented biofeedback training is superior to sensory biofeedback alone in the treatment of impaired fecal continence after obstetric trauma.