Cost-effectiveness of sacral neuromodulation for chronic refractory constipation in children and adolescents: a Markov model analysis.

AIM: This study aimed to assess the cost-effectiveness of sacral neuromodulation (SNM) compared with conservative treatment in children and adolescents with constipation refractory to conservative management. METHOD: A Markov probabilistic model was used, comparing costs and effectiveness of SNM and conservative treatment in children and adolescents aged 10-18 years with constipation refractory to conservative management. Input for the model regarding transition probabilities, utilities and healthcare costs was based on data from a cohort of patients treated in our centre. This cohort consisted of 30 female patients (mean age 16 years) with functional constipation refractory to conservative management. The mean duration of laxative use in this group was 5.9 years. All patients had a test SNM, followed by a permanent SNM in 27/30. Median follow-up was 22.1 months (range 12.2-36.8). The model was run to simulate a follow-up period of 3 years. RESULTS: The mean cumulative costs for the SNM group and the conservative treatment group were €17 789 (SD €2492) and €7574 (SD €4332) per patient, respectively. The mean quality adjusted life years (QALYs) in the SNM group was 1.74 (SD 0.19), compared with 0.86 (SD 0.14) in the conservatively managed group. The mean incremental cost-effectiveness ratio was €12 328 per QALY (SD €4788). Sensitivity analysis showed that the outcomes were robust to a wide range of model assumptions. CONCLUSION: Chronic constipation seriously affects the quality of life of children and adolescents. Preliminary evidence suggests that SNM can improve symptoms and quality of life at a reasonable cost.

Randomized clinical trial of percutaneous tibial nerve stimulation versus sham electrical stimulation in patients with faecal incontinence.

BACKGROUND: The aim was to assess the effects of percutaneous tibial nerve stimulation (PTNS) in the treatment of faecal incontinence (FI) by means of an RCT. METHODS: Patients aged over 18 years with FI were included in a multicentre, single-blinded RCT. The primary endpoint was reduction in the median or mean number of FI episodes per week. Secondary endpoints were changes in measures of FI severity, and disease-specific and generic quality of life. Outcomes were compared between PTNS and sham stimulation after 9 weeks of treatment. RESULTS: A higher proportion of patients in the PTNS (13 of 29) than in the sham (6 of 30) group showed a reduction of at least 50 per cent in the median number of FI episodes/week (incidence rate ratio (IRR) 2·40, 95 per cent c.i. 1·10 to 5·24; P = 0·028), but not in the mean number of episodes/week (10 of 29 versus 8 of 30; IRR 1·42, 0·69 to 2·92; P = 0·347). The absolute median number of FI episodes per week decreased in the PTNS but not in the sham group (IRR 0·66, 0·44 to 0·98; P = 0·041), as did the mean number (IRR 0·65 (0·45 to 0·97); P = 0·034). Scores on the Cleveland Clinic Florida faecal incontinence scale decreased significantly in both groups, but more steeply in the PTNS group (mean difference -1·3, 95 per cent c.i. -2·6 to 0·0; P = 0·049). The aggregated mental component score of Short Form 36 improved in the PTNS but not in the sham group (mean difference 5·1, 0·5 to 9·6; P = 0·028). CONCLUSION: PTNS may offer a small advantage in the clinical management of FI that is insufficiently responsive to conservative treatment. The key challenge will be to identify patients who may benefit most from this minimally invasive surgical procedure. Registration number: NCT00974909 (http://www.clinicaltrials.gov).

Rectovaginal fistula: a new technique and preliminary results using collagen matrix biomesh.

BACKGROUND: A rectovaginal fistula (RVF) is a debilitating condition that is difficult to treat. Many available techniques are invasive and involve extensive surgery. A local procedure with good closure rates would be preferable as a first step in the treatment of RVF. The aim of this study was the development of a local technique for the closure of RVF with good closure rates to prevent the use of more invasive procedures. METHODS: This was a pilot study. Patients with RVF who had undergone multiple operations in the pelvic area, local radiotherapy, chemotherapy or had been diagnosed with Crohn's disease were included in the study. All had a history of surgery for RVF. A cross-linked collagen matrix biomesh was placed in the rectovaginal septum using a transperineal or a transvaginal approach. The main outcome measure in this study was the closure rate reported as absence of the fistula at 1 year. RESULTS: Twelve patients were included in the study. Absence of fistula at 1 year was 0.64 (95 % confidence interval 0.30-0.85). Three patients (25.0 %) developed a recurrence, two were reoperated on with a gracilis flap transposition, and one was treated with laparoscopic ligation. In one patient (8.3 %), the fistula failed to close within 3 months after the mesh placement. CONCLUSIONS: Our technique shows promising results. A local and simple technique with acceptable closure and morbidity rates, like our local repair with biomesh, would be ideal as a first step in treating RVFs. Long-term results are needed.

Responsiveness and interpretability of incontinence severity scores and FIQL in patients with fecal incontinence: a secondary analysis from a randomized controlled trial.

INTRODUCTION AND HYPOTHESIS: This study aims to assess the responsiveness and interpretability of the Vaizey score, Wexner score, and the Fecal Incontinence Quality of Life Scale (FIQL) for use in the evaluation of patients with fecal incontinence (FI). METHODS: Eighty patients with FI with a mean age of 59.3 (SD ± 11.9) were enrolled in a randomized controlled trial. The patient-reported outcomes were tested for internal and external responsiveness, longitudinal construct validity, and interpretability. RESULTS: All total scores proved to have both adequate to excellent responsiveness and longitudinal construct validity, and changes were in agreement with subjective improvement. Due to variability in minimally important change estimates (Vaizey score -5 to -3, Wexner score -3 to -2, FIQL 1.1 to 1.2), they should be used as indicators. All patient-reported outcomes showed psychometric or practical limitations. CONCLUSIONS: The instruments available to date to evaluate severity and quality of life in FI do not yet attain the highest levels of psychometric soundness. As the focus of patients may differ from that of physicians, it is recommended that several measures should be included for evaluation. So far, there are suggestions that the Wexner score is most suitable for severity assessment and the FIQL for evaluating quality of life.

Cost-effectiveness analysis of sacral neuromodulation for faecal incontinence in The Netherlands.

AIM: Sacral neuromodulation (SNM) plays a major part in the algorithm of management of faecal incontinence, but there are limited data on its cost-effectiveness. This study aimed to analyse this and the quality-adjusted life-years (QALYs) associated with two different treatment algorithms. The first (SNM-) included use of an artificial sphincter [dynamic graciloplasty (DGP) (50%) and artificial bowel sphincter (ABS) (50%)]. The second (SNM+) included SNM (80% of cases) and artificial sphincter (DGP 10%; ABS 10%) The incidence of sphincteroplasty was assumed to be equal in both algorithms. METHOD: A Markov model was developed. A hypothetical cohort of patients was run through both strategies of the model. A mailed EuroQoL-5D questionnaire was used to determine health-related quality of life. Costs were reproduced from the Maastricht University Medical Centre prospective faecal incontinence database. The time scale of the analysis was 5 years. RESULTS: The former treatment protocol cost €22,651 per patient and the latter, after the introduction of SNM, cost €16,473 per patient. The former treatment protocol resulted in a success rate of 0.59 after 5 years, whereas with the introduction of SNM this was 0.82. Adhering to the former treatment protocol yielded 4.14 QALYs and implementing the latter produced 4.21 QALYs. CONCLUSION: The study demonstrated that introducing SNM in the surgical management algorithm for faecal incontinence was both more effective and less costly than DGP or ABS without SNM. This justifies adequate funding for SNM for patients with faecal incontinence.

Sexual response in patients treated with sacral neuromodulation for lower urinary tract symptoms or fecal incontinence.

OBJECTIVES: To determine whether sacral neuromodulation (SNM) for urinary symptoms or fecal incontinence gives improvement of female sexual function and whether improvement is due to physiological or psychological factors. METHODS: Between 2002 and 2008, 8 patients had an array of questionnaires before and after SNM implantation. The questionnaires were: the Questionnaire for Screening for Sexual Dysfunctions, the Golombok Rust Inventory of Sexual Satisfaction, the Symptom Checklist-90, the Maudsley Marital Questionnaire and the McGill-Mah Orgasm Questionnaire. Three of these 8 patients underwent vaginal plethysmography before and after implantation. RESULTS: No statistically significant changes were found, although there seems to be a trend toward improvement in orgasm scores. In plethysmography all 3 patients showed increased vaginal pulse amplitude with the stimulator turned on with both erotic and non-erotic stimuli. CONCLUSIONS: This study does not show a clear effect of SNM on sexual function, although there seems to be an improvement in orgasm scores. The lack of response on psychological questionnaires and the increase in vaginal pulse amplitude after SNM implantation indicate that there might be a physiological response.

Sacral nerve modulation for defaecation and micturition disorders in patients with spina bifida.

AIM: Sacral nerve modulation is a well accepted method for the treatment of defaecation disorders and voiding dysfunction. Results of sacral nerve modulation in patients with spinal cord lesions are not well assessed, but preliminary results look poor. Therefore, the purpose of this study was to assess the effectiveness of sacral nerve modulation for defaecation disorders and voiding dysfunction in patients with spina bifida. METHOD: Consecutive patients with spina bifida suffering from a myelomeningocele and combined faecal and urinary functional disorders that were eligible for peripheral nerve evaluation (PNE) were studied. A permanent sacral nerve modulation implantation was performed after successful PNE. RESULTS: Ten patients (four female) were included in this study with a median age of 26.4 (range 11.1-41.0) years. In two the PNE was not possible. The median faecal incontinence days (6.0 vs 3.5) and episodes (8.5 vs 3.5) per 21 days decreased significantly during the 3-week period of PNE (P = 0.033). Only 3/10 (30%) patients had a more than 50% improvement and proceeded to a permanent sacral nerve modulation implantation. In one patient it was not possible to perform the permanent implant. CONCLUSION: Preliminary results of sacral nerve modulation in a subgroup of spina bifida patients with combined faecal and urinary functional disorders look promising, but long-term results in larger patient groups need to be studied.

Neuromodulation for constipation: sacral and transcutaneous stimulation.

Constipation is a frequently occurring digestive ailment that is usually treated conservatively. Neuromodulation is altering function of an organ by altering neural activity. This paper reviews methods of neuromodulation used to treat constipation. This includes direct stimulation of sacral nerves and stimulation across the skin. Direct stimulation of sacral nerves is the most well developed method and is presented in detail. It is generally accepted that the mechanism of action is modulation rather than stimulation so it is called sacral neuromodulation (SNM). SNM involves percutaneous placement of an electrode in the third sacral foramen and implanting a stimulating device under the skin in the buttocks. SNM is founded on the physiological principle that activity in one neural pathway modulates pre-existing activity in another through synaptic interaction. The mechanism of action in constipation may be neuromodulation of the extrinsic neural control of the large bowel or modulation of reflexes inhibiting large bowel function. Limited evidence is available to assess the outcome of SNM in constipation. Results in the medium term seem promising for selected patients with idiopathic slow and normal transit constipation not responding to optimal conservative treatment. Adverse events include electrode migration and infection. The availability of a testing phase provides a predictor of treatment outcome. In addition, transcutaneous stimulation using sticky pad electrodes over the lumbosacral region or acupuncture points has been reported to improve constipation symptoms. In general, the level of evidence is low and further studies are needed.

Status of sacral neuromodulation for refractory constipation.

AIM: This review article aims to provide a brief update on the current data on and position of sacral neuromodulation (SNM) in the specialized management of refractory idiopathic constipation. METHOD: Published evidence from PubMed and our own unpublished data on SNM treatment for refractory idiopathic constipation were used for this evaluation. RESULTS: Seven studies were found in PubMed that covered this topic. The main focus was on the most recently published multicentre nonrandomized European trial. Summary data from our unpublished study on constipation in children are also included. CONCLUSIONS: The use of SNM in the treatment of idiopathic constipation is still in its early phase and while the available efficacy and safety data are limited, they show promising results. As there are few alternatives for this difficult patient group, it is worth offering a percutaneous nerve evaluation (PNE) test, which is known to be a good predictor of postimplant treatment success.

Sacral neuromodulation: long-term outcome and quality of life in patients with faecal incontinence.

AIM: Since 1994 sacral neuromodulation (SNM) has increasingly been used for the treatment of faecal incontinence, but no long-term data in a large group of patients have so far been published. We report long-term outcome and quality of life in the first 50 patients treated by permanent SNM for faecal incontinence. METHOD: We began to use SNM in 2000. Data from the first 50 patients with faecal incontinence who underwent permanent SNM are presented. Efficacy was assessed using a bowel diary and the Quality of Life score was assessed by the Faecal Incontinence Quality of Life questionnaire (FIQOL) and the standard short form health survey questionnaire (SF-36). RESULTS: Over a median follow up of 7.1 (5.6-8.7) years, forty-two (84%) patients had an improvement in continence of over 50%. Median incontinent episodes and days of incontinence per week decreased significantly during follow up (P<0.002). Improvement was seen in all four categories of the FIQOL scale and in some domains of the SF-36 QOL questionnaire. There were no statistically significant changes in the median resting and squeeze anal canal pressures. CONCLUSION: Initial improvement in continence with SNM was sustained in the majority of patients, with an overall success rate of 80% after a permanent implant at 7 years.

Sacral neuromodulation: does it affect the rectoanal angle in patients with fecal incontinence?

BACKGROUND: In the past decade numerous studies have been published on the successful treatment of fecal incontinence with sacral neuromodulation (SNM). The underlying mechanism of action for lower bowel motility disorders has been unclear. In the present study, the effect of SNM on the rectoanal angle in patients with fecal incontinence was investigated. PATIENTS AND METHODS: In 12 consecutive patients who qualified for SNM an X-defecography study was performed before SNM and at 6 months after permanent implant. Three single lateral rectal views were taken: one during rest, one during squeeze, and one during Valsalva's maneuver, after which the patient was asked to evacuate as rapidly and completely as possible during lateral fluoroscopy. At 6 months two further defecography studies were performed, one during stimulation with the pacemaker on and one with the pacemaker off. RESULTS: The defecography studies showed that the rectoanal angle decreased during rest, squeeze, and Valsalva's maneuver. A slight increase in rectoanal angle was seen during defecation. However, the differences did not reach statistical significance. Sacral neuromodulation improved fecal continence significantly in all patients at 6 months. Median incontinence episodes per week decreased from 6.2 to 1.0 (P = 0.001), and incontinent days per week decreased from 3.7 to 1.0 (P = 0.001) with SNM. There were no significant changes in the median resting and squeeze anal canal pressures, 46.5 versus 49.7 mmHg and 67.1 versus 72.3 mmHg, respectively. Median stimulation amplitude at follow-up was 2.7 V (range: 0.9-5.3 V). CONCLUSIONS: Rectoanal angle did not decrease significantly in patients with fecal incontinence during SNM.

[Retrograde irrigation of the colon: treatment for faecal incontinence after low anterior resection]. / Zelf retrograad spoelen: behandeling van fecale incontinentie na lage anterieure resectie.

Two patients, a woman aged 75 and a man aged 63 years, developed faecal incontinence after low anterior resection. Their external sphincter function was intact. They were advised to irrigate their bowel with normal tap water and reached complete pseudocontinence. Faecal incontinence is not always due to sphincter dysfunction. One of the other causes of incontinence is the lack of compliance of the rectum, as seen in patients with a low anterior resection. The part of the colon that has replaced the original rectum is not able to distend in the same manner as the rectum. Irrigation of the colon is a simple means of allowing the patient to achieve pseudocontinence. When the colon is cleaned it will take one or two days before new faeces arrive and a risk for incontinence occurs. It is important to irrigate with safe tap water at a temperature of around 37 degrees C. Most patients treated in this way feel safe to go out again. The irrigation can be performed in patients without the need for extensive diagnostics. This method of irrigation can be used in other forms of faecal incontinence as well.

Neuromodulation for functional bowel disorders.

In patients with functional bowel disorders not responding to maximal medical treatment, bowel lavage or biofeedback therapy, can nowadays be treated by sacral nerve neuromodulation (SNM). SNM therapy has evolved as a treatment for faecal incontinence and constipation. The exact working mechanism remains unknown. It is known that SNM therapy causes direct stimulation of the anal sphincter and causes changes in rectal sensation and several central nervous system areas. The advantage of SNM therapy is the ability to do a minimally invasive temporary screening phase to assess permanent stimulation outcome. Ideal candidates for SNM therapy are not known. Several studies have described positive and negative predictive factors, but the temporary screening remains the instrument of choice. Clinical results are good and as the technique is developing, fewer complications occur. New indications for SNM include constipation and anorectal or pelvic pain.

Retrograde colonic irrigation for faecal incontinence after low anterior resection.

BACKGROUND AND AIMS: This study aims to evaluate the therapeutic effect of retrograde colonic irrigation in patients with faecal incontinence after a low anterior resection for a rectal carcinoma. MATERIALS AND METHODS: Patients with a previous low anterior resection, who were selected for treatment with retrograde colonic irrigation for faecal incontinence between 2005 and 2008, were included in the study. The data from the patients were gathered by chart research and an interview by phone. RESULTS: Thirty patients were included in the study. Three patients died and one patient was not able to answer questions due to a cognitive disorder. The data of the remaining 26 patients were analysed. Five patients had already stopped with the retrograde colonic irrigation treatment due to side effects. Twelve of the 21 patients (57.46%) who still performed RCI became completely (pseudo)continent, three patients (14.2%) were incontinent for flatus and six patients (29.4%) were still incontinent for liquid stool. Five patients stopped with the retrograde colonic irrigation treatment due to side-effects. CONCLUSION: Retrograde colonic irrigation is an effective method to treat patients with faecal incontinence after a low anterior resection for rectal carcinoma. Retrograde colonic irrigation is not invasive and has only mild side effects.

Prospective study of colonic irrigation for the treatment of defaecation disorders.

BACKGROUND: Retrograde colonic irrigation is a possible treatment for defaecation disorders when conservative treatment or surgery has failed. The aim of this prospective study was to investigate its effectiveness. METHODS: Patients were divided into three groups: those with faecal incontinence (A), constipation (B) or both (C). The Biotrol Irrimatic pump or the irrigation bag was used for colonic irrigation. Patients completed a questionnaire at baseline and after 3, 6 and 12 months, as well as a Short Form 36 health survey and an American Society of Colon and Rectal Surgery quality of life questionnaire at baseline and after 6 months. RESULTS: The study included 39 patients (26 women; mean age 58.0 years). In group A, 11 of 18 patients were pseudocontinent for faeces at 3 months (P < 0.001). Parks' incontinence scores decreased for all patients in this group at 3 months (P < 0.001), 6 months (P = 0.036) and 1 year (P = 0.005). In group B, three of ten patients reported a major improvement. The mean score for the feeling of incomplete evacuation decreased at 3 months (P = 0.007), 6 months (P = 0.013) and 1 year (P = 0.036). In group C, six of ten patients became pseudocontinent for faeces (P = 0.009) and three reported improvement in constipation. The overall quality of life scores improved (P = 0.012). CONCLUSION: Retrograde colonic irrigation is an undervalued but effective alternative treatment for intractable defaecation disorders.

Can the outcome of pelvic-floor rehabilitation in patients with fecal incontinence be predicted?

PURPOSE: Pelvic-floor rehabilitation does not provide the same degree of relief in all fecal incontinent patients. We aimed at studying prospectively the ability of tests to predict the outcome of pelvic-floor rehabilitation in patients with fecal incontinence. MATERIALS AND METHODS: Two hundred fifty consecutive patients (228 women) underwent medical history and a standardized series of tests, including physical examination, anal manometry, pudendal nerve latency testing, anal sensitivity testing, rectal capacity measurement, defecography, endoanal sonography, and endoanal magnetic resonance imaging. Subsequently, patients were referred for pelvic-floor rehabilitation. Outcome of pelvic-floor rehabilitation was quantified by the Vaizey incontinence score. Linear regression analyses were used to identify candidate predictors and to construct a multivariable prediction model for the posttreatment Vaizey score. RESULTS: After pelvic-floor rehabilitation, the mean baseline Vaizey score (18, SD+/-3) was reduced with 3.2 points (p<0.001). In addition to the baseline Vaizey score, three elements from medical history were significantly associated with the posttreatment Vaizey score (presence of passive incontinence, thin stool consistency, primary repair of a rupture after vaginal delivery at childbed) (R2, 0.18). The predictive value was significantly but marginally improved by adding the following test results: perineal and/or perianal scar tissue (physical examination), and maximal squeeze pressure (anal manometry; R2, 0.20; p=0.05). CONCLUSION: Additional tests have a limited role in predicting success of pelvic-floor rehabilitation in patients with fecal incontinence.

Severe anal bleeding in Proteus syndrome: a case report.

Proteus syndrome was originally described by Cohen and Hayden in 1979. The disorder was named Proteus syndrome by Wiedmann and colleagues in 1983 after Proteus, the giant Greek god of the sea. Proteus syndrome is a rare, sporadic, congenital polymorphic condition. Approximately 200 cases have been reported in the literature, but none has been associated with anal bleeding from hemorrhoids. We describe the case of a 21-year-old man with Proteus syndrome with severe anal bleeding. A hemorrhoidectomy was assumed to be too risky because of the massive venous abnormalities seen on CT. The patient was successfully treated by Doppler-guided haemorrhoidal artery ligation (DG-HAL). Six months after surgery, the patient has had no further episodes of anal bleeding.

Electrical stimulation and pelvic floor muscle training with biofeedback in patients with fecal incontinence: a cohort study of 281 patients.

PURPOSE: Pelvic floor rehabilitation is an appealing treatment for patients with fecal incontinence but reported results vary. This study was designed to assess the outcome of pelvic floor rehabilitation in a large series of consecutive patients with fecal incontinence caused by different etiologies. METHODS: A total of 281 patients (252 females) were included. Data about medical history, anal manometry, rectal capacity measurement, and endoanal sonography were collected. Subgroups of patients were defined by anal sphincter complex integrity, and nature and possible underlying causes of fecal incontinence. Subsequently patients were referred for pelvic floor rehabilitation, comprising nine sessions of electric stimulation and pelvic floor muscle training with biofeedback. Pelvic floor rehabilitation outcome was documented with Vaizey score, anal manometry, and rectal capacity measurement findings. RESULTS: Vaizey score improved from baseline in 143 of 239 patients (60 percent), remained unchanged in 56 patients (23 percent), and deteriorated in 40 patients (17 percent). Mean Vaizey score reduced with 3.2 points (P < 0.001). A Vaizey score reduction of >or= 50 percent was observed in 32 patients (13 percent). Mean squeeze pressure (+5.1 mmHg; P = 0.04) and maximal tolerated volume (+11 ml; P = 0.01) improved from baseline. Resting pressure (P = 0.22), sensory threshold (P = 0.52), and urge sensation (P = 0.06) remained unchanged. Subgroup analyses did not show substantial differences in effects of pelvic floor rehabilitation between subgroups. CONCLUSIONS: Pelvic floor rehabilitation leads overall to a modest improvement in severity of fecal incontinence, squeeze pressure, and maximal tolerated volume. Only in a few patients, a substantial improvement of the baseline Vaizey score was observed. Further studies are needed to identify patients who most likely will benefit from pelvic floor rehabilitation.

Sacral neuromodulation; does it affect colonic transit time in patients with faecal incontinence?

OBJECTIVE: Sacral neuromodulation (SNM) has been a successful treatment in urinary voiding disorders for years. A concomitant effect on bowel function was observed leading to the treatment of faecal incontinence with SNM. In this study we describe the effect of SNM on bowel frequency and (segmental) colonic transit time. PATIENTS AND METHODS: Fourteen patients with faecal incontinence who qualified for permanent SNM underwent a colon transit study before and one month after permanent implant. Patients completed a three-week bowel habits diary before and during stimulation. RESULTS: Median incontinence episodes and days per week before SNM were, 8.7 and 4.2, respectively, and both decreased significantly to 0.67 (P = 0001) and 0.5 (P = 0001) during trial screening and to 0.33 (P = 0001) and 0.33 (P = 0001) after permanent implant. The median number of bowel movements per week decreased from 14.7 (6.7-41.7) to 10.0 (3.7-22.7)(P = 0005) during trial screening and to 10.0 (6.0-24.3)(P = 0008) during permanent stimulation. Resting and squeeze pressures did not change significantly during stimulation. Segmental colonic transit time before and during stimulation for right colon, left colon and recto sigmoid were, respectively, 6 (0-25) vs 5 (0-16) hours, 2 (0-29) vs 4 (0-45) hours and 7 (28) vs 8 (0-23) hours. No significant changes were found in both segmental and total colonic transit time; 17 (1-65) vs 25 (0-67) hours. CONCLUSION: SNM in patients with fecal incontinence led to a significant decrease of bowel movements however (segmental) colonic transit time was not influenced.

Effect of sacral neuromodulation on the rectum.

BACKGROUND: Sacral neuromodulation (SNM) is a new treatment for faecal incontinence. At present the exact underlying mechanism is still unclear. Modulation of the sacral reflex arcs might have an effect on rectal sensitivity, wall tension and compliance. METHODS: Fifteen consecutive patients with faecal incontinence who qualified for SNM underwent barostat measurements before and during neuromodulation. An 'infinitely' compliant plastic bag with a volume of 600 ml was placed in the rectum and connected to a computer-controlled barostat system. An isobaric phasic distension protocol was used. Patients were asked to report rectal filling sensations: first sensation (FS), earliest urge to defaecate (EUD) and an irresistible, painful urge to defaecate (maximum tolerated volume; MTV). Rectal wall tension and compliance were calculated. RESULTS: During isobaric phasic distension each patient experienced all rectal filling sensations at the time of stimulation. Median volume thresholds decreased significantly during stimulation, from 98.1 to 44.2 ml for FS (P = 0.003), from 132.3 to 82.8 ml for EUD (P = 0.001) and from 205.8 to 162.8 ml for MTV (P = 0.002). Pressure thresholds tended to be lower for all filling sensations, but only that to evoke MTV was reduced significantly by stimulation (37.3 versus 30.3 mmHg; P = 0.005). Median rectal wall tension for all filling sensations decreased significantly with stimulation. There was no significant difference between compliance before and during stimulation. CONCLUSION: SNM affects rectal sensory perception, but further research is required to clarify the mechanism.