Anorectal malformation with long perineal fistula: one of a special type.

The anorectal malformation with long perineal fistula is a rare anomaly in the spectrum of anorectal malformations. Aim of the study is to describe the series of patients with anorectal malformation with long perineal fistula and compare the outcome with patient with standard perineal fistula. From March 2012 to January 2019, 7 patients who suffered from anorectal malformation with long perineal fistula were retrospectively reviewed. Three were operated on primarily by our department, and 4 cases were re-operated after a perineal anoplasty repair performed elsewhere. Four were operated by laparoscopy assisted anorectoplasty, and 3 cases were repaired by posterior sagittal anorectoplasty. The follow-up outcomes were compared with 71 cases of normal perineal fistula (NPF) in the same period. 7 cases have been followed up for 0.5-4 years (M = 2.57 ± 1.26) after definitive surgery. Their bowel function score was lower than normal perineal fistula (SPF = 12, range: 5-18; NPF = 18.5, range: 18-20). Four cases underwent anorectomanometry. The incidence of rectoanal inhibitory reflex was lower in the special type group. (p = 0.14). Three cases of contrast enema using barium: 2 cases of colorectal dilatation and thickening changes, 1 case showed no obvious abnormalities. Anorectal perineal fistula should be examined by distal colostogram at preoperation. This should be altered in: When suspecting a case of anorectal malformation type long perineal fistula a preoperative contrast enema could give insight of the anatomy befor performing a anoplasty.

A multicenter study of anorectal pressures and rectal sensation measured with portable manometry in healthy women and men.

BACKGROUND: The equipment and methods for performing anorectal manometry and biofeedback therapy are different and not standardized. Normal values are influenced by age and sex. Our aims were to generate reference values, examine effects of gender and age, and compare anorectal pressures measured with diagnostic and biofeedback catheters and a portable manometry system. METHODS: In this multicenter study, anorectal pressures at rest, during squeeze, and evacuation were measured with diagnostic and biofeedback catheters using Mcompass™ portable device in healthy subjects. Balloon expulsion time and rectal sensation were evaluated. The effects of age and gender were assessed. RESULTS: The final dataset comprised 108 (74 women) of 124 participants with normal rectal balloon expulsion time (less than 60 s). During squeeze, anal resting pressure increased by approximately twofold in women and threefold in men. During evacuation, anal pressure exceeded rectal pressure in 87 participants (diagnostic catheter). The specific rectoanal pressures (e.g., resting pressure) were significantly correlated and not different between diagnostic and biofeedback catheters. With the diagnostic catheter, the anal squeeze pressure and rectal pressure during evacuation were greater in men than women (p ≤ 0.02). Among women, women aged 50 years and older had lower anal resting pressure; rectal pressure and the rectoanal gradient during evacuation were greater in older than younger women (p ≤ 0.01). CONCLUSIONS: Anal and rectal pressures measured with diagnostic and biofeedback manometry catheters were correlated and not significantly different. Pressures were influenced by age and sex, providing reference values in men and women.

Effects of psychosensory stimulation on anal pressures: Effects of alfuzosin.

BACKGROUND: Our aim is to explain the lack of clarity in the ways in which anxiety and depression, which are common in defecatory disorders (DD), may contribute to the disorder. In this study, we evaluate the effects of mental stress and relaxation on anal pressures and the mechanisms thereof. METHODS: In 38 healthy women and 36 DD patients, rectoanal pressures were assessed at rest and during mental stressors (ie, word-color conflict [Stroop] and mental arithmetic tests) and mental relaxation, before and after randomization to placebo or the adrenergic α1 -antagonist alfuzosin. KEY RESULTS: During the baseline Stroop test, the anal pressure increased by 6 ± 13 mm Hg (mean ± SD, P = 0.004) in healthy women and 9 ± 10 mm Hg (P = 0.0001) in constipated women. During mental arithmetic, the anal pressure increased in healthy (4 ± 8 mm Hg, P = 0.002) and constipated women (5 ± 9 mm Hg, P = 0.004). After relaxation, anal pressure declined (P = 0.0004) by 3 ± 4 mm Hg in DD patients but not in controls. Alfuzosin reduced (P = 0.0001) anal resting pressure (by 31 ± 19 mm Hg) vs placebo (16 ± 18 mm Hg). However, during the postdrug Stroop test, anal pressure increased (P = 0.0001) in participants who received alfuzosin but not placebo. CONCLUSIONS & INFERENCES: In healthy controls and DD patients, mental stressors likely increased anal pressure by contracting the internal anal sphincter; relaxation reduced anal pressure in DD patients. Alfuzosin reduced anal resting pressure but did not block the Stroop-mediated contractile response, which suggests that this response is not entirely mediated by adrenergic α1 receptors.

Anorectal manometry assessment of sphincter relaxation after local-regional anesthesia with posterior perineal block.

INTRODUCTION: Since the 1970s, in the USA, we witnessed a progressive increase of one-day surgical procedures. This attitude soon gained ground in Europe as well. In proctology, this kind of clinical approach has always been limited by the acute sensitivity of the anal- perineal area and by difficulties in attaining a complete sphincter relaxation with local anesthesia. Posterior perineal block seems to be associated with both a good pain control and an effective sphincter relaxation. MATERIAL AND METHODS: Between January 2017 and January 2018, we enrolled in our study 33 patients suffering from hemorrhoidal disease. They were all subjected to posterior perineal block. We measured anal resting pressure and squeeze pressure before and after anesthesia. Measurements where taken 5 minutes before and 15 minutes after the administration of local. RESULTS: We registered an average decrease of 39,2% of resting pressure and of 45,4% of squeeze pressure. CONCLUSIONS: We may state that perineal posterior block, while reducing striated muscle contractile activity, also causes a relevant reduction of anal basal tone. During surgical procedures done under regional anesthesia, we experienced a good sphincter relaxation, which was comparable, if not equal, to that induced by general anesthesia. In fact, 10 to 15 minutes after performing the block you could observe the elevation of the inferior margin of the exterior sphincter and the concomitant descent of the inferior margin of the internal sphincter (coaxial dislocation). KEY WORDS: Anorectal manometry, Anesthesia, Local-regional, Perineal block.

Home-based versus office-based biofeedback therapy for constipation with dyssynergic defecation: a randomised controlled trial.

BACKGROUND: Office-based biofeedback therapy is effective for constipation with dyssynergic defecation, but must be performed by skilled staff, is only available in selected centres, and requires multiple visits. The efficacy of home-based biofeedback therapy is unknown. We compared clinical and subjective outcomes with home-based and office-based approaches. METHODS: In this randomised controlled trial, eligible patients were adult outpatients (age 18-80 years) who met the Rome III criteria for functional constipation and who had been referred to a tertiary-care centre after non-response to routine management, and who had dyssynergic defecation. Patients were randomly assigned according to a schedule generated in advance by the study biostatistician, in permuted blocks of four, to receive office-based or home-based biofeedback therapy. Office-based biofeedback comprised therapist-guided pelvic floor training for six sessions over 3 months (visits every 2 weeks). Home-based biofeedback comprised 20 min self-training sessions twice per day, in which a self-inserted probe was used to provide visual feedback via a handheld monitoring device of anal sphincter pressure and push effort. Patients recorded in diaries the time of each defecation attempt, stool consistency, straining effort, feeling of incomplete evacuation, need for digital assistance with stooling, and satisfaction with bowel function, from 1 week before enrolment to the end of follow-up. Treatment responders were defined post hoc as those with normalisation of dyssynergic defecation and an increase in the number of complete spontaneous bowel movements per week by 3 months. Cost outcomes calculated from health-care costs and loss of salary were assessed from hospital billing and medical records and questionnaires. Primary outcome measures were the presence of a dyssynergic pattern during attempted defecation, balloon expulsion time, the number of complete spontaneous bowel movements per week, and satisfaction with bowel function, assessed by intention to treat (non-inferiority) and per protocol. This trial is registered with ClinicalTrials.gov, number NCT03202771. FINDINGS: Of 300 patients screened we enrolled 100, from Jan 7, 2005, to Jan 31, 2010. 83 patients completed training (38 [76%] of 50 in the home-based biofeedback group and 45 [90%] of 50 in the office-based biofeedback group). 34 (68%) patients in the home-based group and 35 (70%) in the office-based group were classified as responders. All primary outcomes improved significantly from baseline in the two treatment groups (all p<0·0001). Home-based biofeedback therapy was non-inferior to office-based therapy for number of complete spontaneous bowel movements per week, satisfaction with bowel function, and balloon expulsion time in the intention-to-treat and per-protocol analyses, and for dyssynergia in the per-protocol analysis. No adverse events were reported. The median cost of home-based biofeedback therapy was significantly lower than that for office-based treatment (US$1081·70, IQR 794·90-1399·30 vs $1942·50, 1621·70-2369·00, p=0·009). INTERPRETATION: Home-based and office-based biofeedback therapy for dyssynergic defecation improved bowel symptoms and physiology with similar efficacy. A home-based programme could substantially broaden the availability and use of this treatment. FUNDING: National Institutes of Health.

[Home training as a treatment of faecal incontinence and sphincter dyssynergia]. / Entrenamiento anorrectal domiciliario como tratamiento de la encopresis y disinergia esfinteriana.

OBJECTIVE: The defecation disorders represents the 3% of consultations in pediatrics patients. Our goal was to demonstrate the effectiveness and efficiency of the reeducation of the defecation maneuver through home training in patients with encopresis and sphincter dyssynergia. MATERIAL AND METHODS: Study of patients with fecal incontinence treated with home training at our center between 2014-2015. Anorectal manometry was performed and was valued defecation maneuver by expulsion of rectal probe with or without the ball. Daily sessions were performed using a Foley catheter (18-20Fr.) with progressive filling of the balloon, maximum 20cc. The response to the treatment was assessed in terms of episodes of soiling. RESULTS: Seven patients (6 males and 1 female) with a mean age of 9.7 years (range, 5-15) were included; two patients with anorectal malformation history, 1 Hirschsprung disease, 1 sacrococcygeal teratoma and 3 functional encopresis. Three patients had soiling episodes daily and 4 patients frequently. The mean basal pressure of anal channel was 32.34mmHg (range, 11.74-50.75) with negative defecation maneuver in 2 cases, deficient in 3 and dyssynergic in 2 patients. The mean time of biofeedback therapy to be asymptomatic was 5.14 months (range, 2-11), with a mean of 16.14 months (range, 3-24), with the 7 patients currently maintained clean. CONCLUSIONS: The present study suggests that re-education of defecation maneuver through home training, seems to be an effective and efficient therapy, achieving excellent results in medium term.

OBJETIVO: Los trastornos de la defecación representan el 3% de las consultas en pediatría. Nuestro objetivo fue demostrar la eficacia y eficiencia de la reeducación en la maniobra defecatoria mediante el entrenamiento domiciliario en los pacientes con encopresis y disinergia esfinteriana. MATERIAL Y METODOS: Estudio de los pacientes con encopresis tratados mediante entrenamiento domiciliario en nuestro centro entre 2014-2015. Se realizó manometría anorrectal y fue valorada la maniobra defecatoria mediante la expulsión o no de la sonda rectal con o sin balón. Se realizaron sesiones diarias de forma domiciliaria empleando una sonda de Foley (18-20 Fr.) con llenado progresivo del balón, máximo 20 cc. Se evaluó la respuesta al tratamiento en función de la presencia de manchado. RESULTADOS: Se incluyeron 7 pacientes (6 varones y 1 mujer) con edad media de 9.7 años (rango, 5-15); dos con antecedente de malformación anorrectal, una enfermedad de Hirschsprung, 1 teratoma sacrococcígeo y 3 encopresis funcionales. Tres pacientes presentaban manchado diario y 4 de forma frecuente. La media de presión basal del canal fue de 32,34 mmHg (rango, 11,74-50,75) con maniobra defecatoria negativa en 2 casos, deficiente en 3 y disinérgica en 2. La media de tiempo realizando el entrenamiento intestinal hasta lograr estar asintomáticos fue 5.14 meses (rango, 2-11), con un seguimiento medio de 16,14 meses (rango, 3-24), manteniéndose limpios actualmente los 7 pacientes. CONCLUSIONES: El presente estudio sugiere que la reeducación de la maniobra defecatoria mediante entrenamiento domiciliario parece ser una terapia eficaz y eficiente, logrando excelentes resultados a medio plazo.

Efficacy of Biofeedback Therapy in the Treatment of Dyssynergic Defecation in Community-Dwelling Elderly Women.

AIM OF THE STUDY: The aim of this study was to evaluate the efficacy of biofeedback therapy in the treatment of dyssynergic defecation in chronically constipated community-dwelling elderly women. MATERIALS AND METHODS: After an initial assessment phase carried out during 1 month, 20 chronically constipated women with dyssynergic defecation were randomly assigned to either electromyographic biofeedback (EMG-BF) group (n=10) or control group (n=10). Outcome measures used to evaluate the efficacy of treatment were weekly stool frequency, sensation of incomplete evacuation, difficulty evacuation level, mean EMG-activity (µV) of the external anal sphincter during straining to defecate and Anismus index. RESULTS: The results obtained in this randomized controlled trial showed significant differences between the groups in all the dependent variables after 1 month of treatment. Moreover, there was no difference between the groups neither in age nor in the duration of chronic constipation symptoms. At the follow-up, 3 months later, clinical gains were maintained. CONCLUSIONS: This study demonstrates that the EMG-BF is an effective behavioral therapy for the treatment of dyssynergic defecation in community-dwelling elderly women.

Integrated low-intensity biofeedback therapy in fecal incontinence: evidence that "good" in-home anal sphincter exercise practice makes perfect.

BACKGROUND: Biofeedback therapy (BFT) is an established treatment for fecal incontinence (FI), with access often being restricted to tertiary centers due to resources and the perceived requirement for high-intensity regimes. However, the optimal regime remains unknown. We evaluated outcomes from our low-intensity integrated BFT program in a secondary care center. METHODS: Outcomes of our BFT service for FI were evaluated retrospectively. Response was defined by ≥50% improvement in FI frequency from baseline or complete continence. Responders were compared to non-responders for factors including symptoms, manometry data, sphincter exercise technique and duration of practice, and the number and frequency of sessions. Where patients dropped out, outcomes and the reason for dropout were obtained retrospectively. KEY RESULTS: Fecal incontinence patients (n=205, median 62 years, 72% female) attended a median (IQR) 3 (2) BFT sessions with 55 (36) days between visits. Overall, 146/205 (71%) responded with 97/205 (47%) achieving continence. Fecal incontinence frequency improved dramatically in completed cases (P=0.000). While non-response was associated with males (P=0.03) and dropout (P=0.000), "good" anal sphincter exercise technique (P=0.008) and longer in-home practice (P=0.007) and more sessions (P=0.04) were associated with response. Dropout rate was 80/205 (39%), with the reason for dropout being obtained in 80%. CONCLUSIONS & INFERENCES: Despite low-intensity BFT, comparable outcomes to data from tertiary centers were achieved. Our data emphasize the importance of technique and in-home practice of anal sphincter exercises. Customizing BFT intensity based on predictive factors and encouraging in-home practice may optimize outcomes, reduce dropout rates, and rationalize resources.

Comparison of saddle, lumbar epidural and caudal blocks on anal sphincter tone: A prospective, randomized study.

Objective To compare the effects of saddle, lumbar epidural and caudal blocks on anal sphincter tone using anorectal manometry. Methods Patients undergoing elective anorectal surgery with regional anaesthesia were divided randomly into three groups and received a saddle (SD), lumbar epidural (LE), or caudal (CD) block. Anorectal manometry was performed before and 30 min after each regional block. The degree of motor blockade of the anal sphincter was compared using the maximal resting pressure (MRP) and the maximal squeezing pressure (MSP). Results The study analysis population consisted of 49 patients (SD group, n = 18; LE group, n = 16; CD group, n = 15). No significant differences were observed in the percentage inhibition of the MRP among the three regional anaesthetic groups. However, percentage inhibition of the MSP was significantly greater in the SD group (83.6 ± 13.7%) compared with the LE group (58.4 ± 19.8%) and the CD group (47.8 ± 16.9%). In all groups, MSP was reduced significantly more than MRP after each regional block. Conclusions Saddle block was more effective than lumbar epidural or caudal block for depressing anal sphincter tone. No differences were detected between lumbar epidural and caudal blocks.

Electrical Stimulation Followed by Mesenchymal Stem Cells Improves Anal Sphincter Anatomy and Function in a Rat Model at a Time Remote From Injury.

BACKGROUND: We have explored cell-based therapy to aid anal sphincter repair, but a conditioning injury is required to direct stem cells to the site of injury because symptoms usually manifest at a time remote from injury. OBJECTIVE: We aimed to investigate the effect of local electrical stimulation followed by mesenchymal stem cell delivery on anal sphincter regeneration at a time remote from injury. DESIGN AND MAIN OUTCOME MEASURES: With the use of a rat model, electrical stimulation parameters and cell delivery route were selected based on in vivo cytokine expression and luciferase-labeled cell imaging of the anal sphincter complex. Three weeks after a partial anal sphincter excision, rats were randomly allocated to 4 groups based on different local interventions: no treatment, daily electrical stimulation for 3 days, daily stimulation for 3 days followed by stem cell injection on the third day, and daily electrical stimulation followed by stem cell injection on the first and third days. Histology-assessed anatomy and anal manometry evaluated physiology 4 weeks after intervention. RESULTS: The electrical stimulation parameters that significantly upregulated gene expression of homing cytokines also achieved mesenchymal stem cell retention when injected directly in the anal sphincter complex in comparison with intravascular and intraperitoneal injections. Four weeks after intervention, there was significantly more new muscle in the area of injury and significantly improved anal resting pressure in the group that received daily electrical stimulation for 3 days followed by a single injection of 1 million stem cells on the third day at the site of injury. LIMITATION: This was a pilot study and therefore was not powered for functional outcome. CONCLUSIONS: In this rat injury model with optimized parameters, electrical stimulation with a single local mesenchymal stem cell injection administered 3 weeks after injury significantly improved both new muscle formation in the area of injury and anal sphincter pressures.

Systematic review of the impact of sacral neuromodulation on clinical symptoms and gastrointestinal physiology.

BACKGROUND: Sacral neuromodulation (SNM) has emerged as a treatment option for faecal incontinence (FI). However, its objective effect on symptoms and anorectal function is inconsistently described. This study aimed to systematically review the impact of SNM on clinical symptoms and gastrointestinal physiology in patients with FI, including factors that may predict treatment outcome. METHODS: An electronic search of MEDLINE (1946-2014)/EMBASE database was performed in accordance with PRISMA guidelines. Articles that reported the relevant outcome measures following SNM were included. Clinical outcomes evaluated included: frequency of FI episodes, FI severity score and success rates. Its impact on anorectal and gastrointestinal physiology was also evaluated. RESULTS: Of 554 citations identified, data were extracted from 81 eligible studies. Meta-analysis of the data was precluded due to lack of a comparison group in most studies. After permanent SNM, 'perfect' continence was noted in 13-88% of patients. Most studies reported a reduction in weekly FI episodes (median difference of the mean -7.0 (range: -24.8 to -2.7)) and Wexner scores (median difference of the mean -9 (-14.9 to -6)). A trend towards improved resting and squeeze anal pressures and a reduction in rectal sensory volumes were noted. Studies failed to identify any consistent impact on other physiological parameters or clinicophysiological factors associated with success. CONCLUSION: SNM improves clinical symptoms and reduces number of incontinence episodes and severity scores in patients with FI, in part by improving anorectal physiological function. However, intervention studies with standardized outcome measures and physiological techniques are required to robustly assess the physiological impact of SNM.

Combination therapy with biofeedback, loperamide, and stool-bulking agents is effective for the treatment of fecal incontinence in women - a randomized controlled trial.

OBJECTIVE: Biofeedback and medical treatments have been extensively used for moderate fecal incontinence (FI). There is limited data comparing and combining these two treatments. The objective of this study was to evaluate the effect of biofeedback and medical treatments, separately and in combination. MATERIAL AND METHODS: Sixty-four consecutive female patients, referred to a tertiary centre for FI, were included. The patients were randomized to start with either biofeedback (4-6 months) or medical treatment with loperamide and stool-bulking agents (2 months). Both groups continued with a combination of treatments, i.e. medical treatment was added to biofeedback and vice versa. A two-week prospective bowel symptom diary and anorectal physiology were evaluated at baseline, after single- and combination treatments. RESULTS: Fifty-seven patients completed the study. Median number of leakage episodes during two weeks decreased from 6 to 3 (p < 0.0001) from baseline to completion. The patients showed a significant (1) decrease in number of leakages without forewarning (p = 0.04); (2) decrease in number of stools with urgency (p = 0.001); (3) decrease in number of loose stool consistency; and (4) an increase in rectal sensory thresholds, both for maximum tolerable rectal pressure and first sensation (<0.01). The combination treatment was superior to both single treatments in terms of symptoms and functions. There was no significant difference between the two groups at any time point. CONCLUSIONS: The combination therapy with biofeedback and medical treatment is effective for symptom relief in FI. The symptom improvement was associated with improved fecal consistency, reduced urgency, and increased rectal sensory thresholds.

Influence of a distraction task on pelvic floor muscle contraction.

AIMS: Attention may play a key role in the contraction of pelvic floor muscles in stressful situations, meaning that mental distraction may be involved in urinary incontinence. METHODS: Informed consent was obtained from 20 healthy volunteers. The electromyographic (EMG) activity of the external anal sphincter (EAS) was recorded during voluntary contraction elicited by local stimulation. The trials were carried out twice: combined (or not) with a mental distraction task (PASAT), Paced auditory serial additional test. Reaction time, latency between the stimulus and maximum EAS EMG activity, duration of the contraction, maximum EAS EMG activity, and the area under the EAS EMG activity curve were measured. RESULTS: The mental distraction task led to a 3.98 times greater reaction time (RT), (P = 0.00001 Wilcoxon's test). The RT increased from 217 (IQR: 170-270) to 779 msec (IQR: 550-1,025, P < 0.0001) when the EAS contraction was combined with PASAT. However, the maximum EAS EMG activity was weaker during PASAT than in the absence of a mental distraction task: 0.0850 mv versus 0.0701 mv, that is, 1.21 times weaker (P = 0.00077, Wilcoxon's test). Finally, when the two conditions (respectively with and without the mental distraction task) were compared, no significant difference was found in the area under the EAS EMG activity curve (0.0157 mv sec vs. 0.0162 mv sec, ratio 1.01, P = 0.52). CONCLUSIONS: The mental distraction task altered voluntary contraction of the pelvic floor muscles.

Restoration of anal sphincter function after myoblast cell therapy in incontinent rats.

Fecal incontinence (FI) remains a socially isolating condition with profound impact on quality of life for which autologous myoblast cell therapy represents an attractive treatment option. We developed an animal model of FI and investigated the possibility of improving sphincter function by intrasphincteric injection of syngeneic myoblasts. Several types of anal cryoinjuries were evaluated on anesthetized Fischer rats receiving analgesics. The minimal lesion yielding sustainable anal sphincter deficiency was a 90° cryoinjury of the sphincter, repeated after a 24-h interval. Anal sphincter pressure was evaluated longitudinally by anorectal manometry under local electrostimulation. Myoblasts were prepared using a protocol mimicking a clinical-grade process and further transduced with a GFP-encoding lentiviral vector before intrasphincteric injection. Experimental groups were uninjured controls, cryoinjured + PBS, and cryoinjured + myoblasts (different doses or injection site). Myoblast injection was well tolerated. Transferred myoblasts expressing GFP integrated into the sphincter and differentiated in situ into dystrophin-positive mature myofibers. Posttreatment sphincter pressures increased over time. At day 60, pressures in the treated group were significantly higher than those of PBS-injected controls and not significantly different from those of normal rats. Longitudinal follow-up showed stability of the therapeutic effect on sphincter function over a period of 6 months. Intrasphincteric myoblast injections at the lesion borders were equally as effective as intralesion administration, but an injection opposite to the lesion was not. These results provide proof of principle for myoblast cell therapy to treat FI in a rat model. This strategy is currently being evaluated in humans in a randomized double-blind placebo-controlled clinical trial.

High-resolution anorectal manometry in newborns: normative values and diagnostic utility in Hirschsprung disease.

BACKGROUND: Conventional methods of screening for Hirschsprung disease (HD) in newborns (barium enema, BE; anorectal manometry, ARM; rectal suction biopsy, RSB) have limitations and/or are invasive. High-resolution anorectal manometry (HR-ARM) is a minimally invasive technique that has potential to overcome most of these limitations, but normative data and performance characteristics have not been reported in newborns. The aims of our study were to assess anorectal sphincter metrics including resting pressure (RP), anal canal length (ACL), and rectoanal inhibitory reflex (RAIR) in healthy and asymptomatic newborns, and to explore the role of HR-ARM in the diagnosis of HD using these normal parameters. METHODS: All procedures were performed using solid state HR-ARM equipment (Medical Measurement Systems, Enchede, The Netherland) by a single operator. In the first phase, 180 asymptomatic newborns (term newborns 95, preterm newborns 85) were studied, and anal RP, ACL, and RAIR were measured. In the second phase, 16 newborns with clinical manifestations of HD were studied (9 of whom had histopathologic confirmation), and parameters compared to asymptomatic newborns. KEY RESULTS: Normative RP values were higher in term newborns compared with preterm newborns (p < 0.05), and correlated with age. Progressive maturation of the anal sphincter was evident with chronologic age, both in preterm and term newborns. RAIR was present in all normal subjects. Using absent RAIR as indicative of HD, HR-ARM had a sensitivity 89% and specificity of 83% compared to RSB; these performance characteristics were better than BE (sensitivity 78%, specificity 17%), with significantly higher diagnostic accuracy (80% vs 53%, respectively, p = 0.009). CONCLUSIONS & INFERENCES: Anorectal sphincter pressure progressively matures with incremental increase in RP during the first months of life. HR-ARM is an effective and safe method that complements the diagnosis of HD in newborns.

Anal acoustic reflectometry predicts the outcome of percutaneous nerve evaluation for faecal incontinence.

BACKGROUND: Sacral nerve stimulation (SNS) is effective for some patients with faecal incontinence. Before insertion of a costly implant, percutaneous nerve evaluation (PNE) is undertaken to identify patients likely to report success from SNS. The aim of this study was to determine whether variables of anal sphincter function measured by anal acoustic reflectometry (AAR) could predict the outcome of PNE for faecal incontinence. METHODS: Women with faecal incontinence undergoing PNE were recruited. AAR, followed by anal manometry, was performed on the day of surgery, immediately before PNE. The outcome of PNE was determined by bowel diary results and incontinence severity score. Patients with a successful PNE outcome were compared with those with an unsuccessful outcome; logistic regression analysis was used to identify any independent predictors of success. RESULTS: Fifty-two patients were recruited, of whom 32 (62 per cent) had a successful PNE outcome and 20 (38 per cent) an unsuccessful outcome. The AAR variable opening pressure was significantly greater in patients who subsequently had a successful PNE result compared with the pressure in patients who did not (28 versus 17 cmH2 O; P = 0·008). No difference was seen in the manometric equivalent, maximum resting pressure. Opening pressure was an independent predictor of success with an odds ratio of 1·08 (95 per cent confidence interval 1·01 to 1·16; P = 0·018). CONCLUSION: AAR is a sensitive test of sphincter function and can identify differences between patients who respond to PNE and those who do not. Opening pressure is an independent predictor of success in PNE, and may be of value in the selection of patients for this expensive treatment option.

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.