Habit training versus habit training with direct visual biofeedback in adults with chronic constipation: A randomized controlled trial.

AIM: The aim was to determine whether specialist-led habit training using Habit Training with Biofeedback (HTBF) is more effective than specialist-led habit training alone (HT) for chronic constipation and whether outcomes of interventions are improved by stratification to HTBF or HT based on diagnosis (functional defaecation disorder vs. no functional defaecation disorder) by radio-physiological investigations (INVEST). METHOD: This was a parallel three-arm randomized single-blinded controlled trial, permitting two randomized comparisons: HTBF versus HT alone; INVEST- versus no-INVEST-guided intervention. The inclusion criteria were age 18-70 years; attending specialist hospitals in England; self-reported constipation for >6 months; refractory to basic treatment. The main exclusions were secondary constipation and previous experience of the trial interventions. The primary outcome was the mean change in Patient Assessment of Constipation Quality of Life score at 6 months on intention to treat. The secondary outcomes were validated disease-specific and psychological questionnaires and cost-effectiveness (based on EQ-5D-5L). RESULTS: In all, 182 patients were randomized 3:3:2 (target 384): HT n = 68; HTBF n = 68; INVEST-guided treatment n = 46. All interventions had similar reductions (improvement) in the primary outcome at 6 months (approximately -0.8 points of a 4-point scale) with no statistically significant difference between HT and HTBF (-0.03 points; 95% CI -0.33 to 0.27; P = 0.85) or INVEST versus no-INVEST (0.22; -0.11 to 0.55; P = 0.19). Secondary outcomes showed a benefit for all interventions with no evidence of greater cost-effectiveness of HTBF or INVEST compared with HT. CONCLUSION: The results of the study at 6 months were inconclusive. However, with the caveat of under-recruitment and further attrition at 6 months, a simple, cheaper approach to intervention may be as clinically effective and more cost-effective than more complex and invasive approaches.

Adult-onset megacolon with focal hypoganglionosis: A detailed phenotyping and prospective cohort study.

BACKGROUND: In this prospective cohort study, we evaluated features of "adult-onset megacolon with focal hypoganglionosis." METHODS: We assessed the radiologic, endoscopic, and histopathologic phenotyping and treatment outcomes of 29 patients between 2017 and 2020. Data from community controls, consisting of 19,948 adults undergoing health screenings, were analyzed to identify risk factors. Experts reviewed clinical features and pathological specimens according to the London Classification for gastrointestinal neuromuscular pathology. KEY RESULTS: The median age of the patients with adult-onset megacolon with focal hypoganglionosis at symptom onset was 59 years (range, 32.0-74.9 years), with mean symptom onset only 1 year before diagnosis. All patients had focal stenotic regions with proximal bowel dilatation (mean diameter, 78.8 mm; 95% confidence interval [CI], 72-86). The comparison with community controls showed no obvious risk factors. Ten patients underwent surgery, and all exhibited significant hypoganglionosis: 5.4 myenteric ganglion cells/cm (interquartile range [IQR], 3.7-16.4) in the stenotic regions compared to 278 cells/cm (IQR, 190-338) in the proximal and 95 cells/cm (IQR, 45-213) in the distal colon. Hypoganglionosis was associated with CD3+ T cells along the myenteric plexus. Colectomy was associated with significant symptom improvement compared to medical treatment [change in the Global Bowel Satisfaction score, -5.4 points (surgery) vs. -0.3 points (medical treatment); p < 0.001]. CONCLUSIONS AND INFERENCES: Adult-onset megacolon with focal hypoganglionosis has distinct features characterized by hypoganglionosis due to inflammation. Bowel resection appears to benefit these patients.

The Clinical Impact of Obesity in Patients With Disorders of Defecation: A Cross-Sectional Study of 1,155 Patients.

INTRODUCTION: Obesity is a global epidemic. Its clinical impact on symptoms of fecal incontinence (FI) and/or constipation and underlying anorectal pathophysiology remains uncertain. METHODS: This is a cross-sectional study of consecutive patients meeting Rome IV criteria for FI and/or functional constipation, with data on body mass index (BMI), attending a tertiary center for investigation between 2017 and 2021. Clinical history, symptoms, and anorectal physiologic test results were analyzed according to BMI categories. RESULTS: A total of 1,155 patients (84% female) were included in the analysis (33.5% normal BMI; 34.8% overweight; and 31.7% obese). Obese patients had higher odds of FI to liquid stools (69.9 vs 47.8%, odds ratio [OR] 1.96 [confidence interval: 1.43-2.70]), use of containment products (54.6% vs 32.6%, OR 1.81 [1.31-2.51]), fecal urgency (74.6% vs 60.7%, OR 1.54 [1.11-2.14]), urge FI (63.4% vs 47.3%, OR 1.68 [1.23-2.29]), and vaginal digitation (18.0% vs 9.7%, OR 2.18 [1.26-3.86]). A higher proportion of obese patients had Rome criteria-based FI or coexistent FI and functional constipation (37.3%, 50.3%) compared with overweight patients (33.8%, 44.8%) and patients with normal BMI (28.9%, 41.1%). There was a positive linear association between BMI and anal resting pressure (ß 0.45, R 2 0.25, P = 0.0003), although the odds of anal hypertension were not significantly higher after Benjamini-Hochberg correction. Obese patients more often had a large clinically significant rectocele (34.4% vs 20.6%, OR 2.62 [1.51-4.55]) compared with patients with normal BMI. DISCUSSION: Obesity affects specific defecatory (mainly FI) and prolapse symptoms and pathophysiologic findings (higher anal resting pressure and significant rectocele). Prospective studies are required to determine whether obesity is a modifiable risk factor of FI and constipation.

Systematic review of preoperative and intraoperative colorectal Anastomotic Leak Prediction Scores (ALPS).

OBJECTIVE: To systematically review preoperative and intraoperative Anastomotic Leak Prediction Scores (ALPS) and validation studies to evaluate performance and utility in surgical decision-making. Anastomotic leak (AL) is the most feared complication of colorectal surgery. Individualised leak risk could guide anastomosis and/or diverting stoma. METHODS: Systematic search of Ovid MEDLINE and Embase databases, 30 October 2020, identified existing ALPS and validation studies. All records including >1 risk factor, used to develop new, or to validate existing models for preoperative or intraoperative use to predict colorectal AL, were selected. Data extraction followed CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies guidelines. Models were assessed for applicability for surgical decision-making and risk of bias using Prediction model Risk Of Bias ASsessment Tool. RESULTS: 34 studies were identified containing 31 individual ALPS (12 colonic/colorectal, 19 rectal) and 6 papers with validation studies only. Development dataset patient populations were heterogeneous in terms of numbers, indication for surgery, urgency and stoma inclusion. Heterogeneity precluded meta-analysis. Definitions and timeframe for AL were available in only 22 and 11 ALPS, respectively. 26/31 studies used some form of multivariable logistic regression in their modelling. Models included 3-33 individual predictors. 27/31 studies reported model discrimination performance but just 18/31 reported calibration. 15/31 ALPS were reported with external validation, 9/31 with internal validation alone and 4 published without any validation. 27/31 ALPS and every validation study were scored high risk of bias in model analysis. CONCLUSIONS: Poor reporting practices and methodological shortcomings limit wider adoption of published ALPS. Several models appear to perform well in discriminating patients at highest AL risk but all raise concerns over risk of bias, and nearly all over wider applicability. Large-scale, precisely reported external validation studies are required. PROSPERO REGISTRATION NUMBER: CRD42020164804.

Supported Intervention Versus Intervention Alone for Management of Fecal Incontinence in Patients With Inflammatory Bowel Disease: A Multicenter Mixed-Methods Randomized Controlled Trial.

PURPOSE: The aims of this study were to test a noninvasive self-management intervention supported by specialist nurses versus intervention alone in patients with inflammatory bowel disease (IBD) experiencing fecal incontinence and to conduct a qualitative evaluation of the trial. DESIGN: Multicenter, parallel-group, open-label, mixed-methods randomized controlled trial (RCT). SUBJECTS AND SETTING: The sample comprised patients from a preceding case-finding study who reported fecal incontinence and met study requirements; the RCT was delivered via IBD outpatient clinics in 6 hospitals (5 in major UK cities, 1 rural) between September 2015 and August 2017. Sixteen participants and 11 staff members were interviewed for qualitative evaluation. METHODS: Adults with IBD completed the study activities over a 3-month period following randomization. Each participant received either four 30-minute structured sessions with an IBD clinical nurse specialist and a self-management booklet or the booklet alone. Low retention numbers precluded statistical analysis; individual face-to-face or telephone interviews, recorded digitally and transcribed professionally, were conducted to evaluate the RCT. Transcripts were analyzed thematically using an inductive method. RESULTS: Sixty-seven participants (36%) of the targeted 186 participants were recruited. The groups comprised 32 participants (17% of targeted participants) allocated to the nurse + booklet intervention and 35 (18.8% of targeted participants) allocated to the booklet alone. Less than one-third (n = 21, 31.3%) completed the study. Given the low recruitment and high attrition, statistical analysis of quantitative data was considered futile. Participant interviews were conducted concerning study participation and 4 themes emerged that described experiences of patients and staff. These data provided insights into reasons for low recruitment and high attrition, as well as challenges of delivering resource-heavy studies in busy health service environments. CONCLUSIONS: Alternative approaches to trials of nurse-led interventions in hospital settings are needed as many interfering factors may prevent successful completion.

Safety and Efficacy of Iltamiocel Cellular Therapy for the Treatment of Fecal Incontinence. Results of a Phase 1/2 Study.

OBJECTIVE: To examine the safety and efficacy of iltamiocel, an investigational cellular therapy of autologous muscle-derived cells, as a treatment for fecal incontinence (FI) in adults. BACKGROUND: Limited therapeutic options are available for patients with FI refractory to conservative treatments. Cell therapy using autologous muscle-derived cells represents a promising, minimally invasive approach for restoring anal sphincter function. METHODS: In this multicenter, prospective, non-randomized study, 48 participants were treated with a single iltamiocel dose of 250×10 6 cells. The primary outcome was the incidence of product or procedure-related adverse events (AEs) and serious AEs. Secondary outcomes were changes in the number of FI episodes, Cleveland Clinic Incontinence Score, Fecal Incontinence Quality of Life, and anorectal manometry at 3, 6, and 12 months compared to baseline. RESULTS: No serious AEs and only one product-related AE of inflammation at the injection site were reported. At 12 months, there was a reduction in median FI episodes (-6.0; 95% confidence interval (CI): -10.0, -1.0) and days with episodes (-4.0; 95% CI: -8.0, -1.0). A ≥50% reduction in FI episodes was observed in 53.7% of participants, and 24.4% had complete restoration of continence. Symptom severity and quality of life improved with mean Cleveland Clinic Incontinence Score reduction (-2.9; 95% CI: -3.7, -2.1), and Fecal Incontinence Quality of Life increased (2.2; 95% CI:1.4, 2.9). No significant changes were detected in anorectal manometry measurements. A history of episiotomy was significantly associated with treatment response in multivariate analysis. CONCLUSION: The administration of iltamiocel cellular therapy is safe. Iltamiocel shows promise for significantly improving fecal incontinence symptoms and quality of life.

Implementation of a batched stepped wedge trial evaluating a quality improvement intervention for surgical teams to reduce anastomotic leak after right colectomy.

BACKGROUND: Large-scale quality improvement interventions demand robust trial designs with flexibility for delivery in different contexts, particularly during a pandemic. We describe innovative features of a batched stepped wedge trial, ESCP sAfe Anastomosis proGramme in CoLorectal SurgEry (EAGLE), intended to reduce anastomotic leak following right colectomy, and reflect on lessons learned about the implementation of quality improvement programmes on an international scale. METHODS: Surgical units were recruited and randomised in batches to receive a hospital-level education intervention designed to reduce anastomotic leak, either before, during, or following data collection. All consecutive patients undergoing right colectomy were included. Online learning, patient risk stratification and an in-theatre checklist constituted the intervention. The study was powered to detect an absolute risk reduction of anastomotic leak from 8.1 to 5.6%. Statistical efficiency was optimised using an incomplete stepped wedge trial design and study batches analysed separately then meta-analysed to calculate the intervention effect. An established collaborative group helped nurture strong working relationships between units/countries and a prospectively designed process evaluation will enable evaluation of both the intervention and its implementation. RESULTS: The batched trial design allowed sequential entry of clusters, targeted research training and proved to be robust to pandemic interruptions. Staggered start times in the incomplete stepped wedge design with long lead-in times can reduce motivation and engagement and require careful administration. CONCLUSION: EAGLE's robust but flexible study design allowed completion of the study across globally distributed geographical locations in spite of the pandemic. The primary outcome analysed in conjunction with the process evaluation will ensure a rich understanding of the intervention and the effects of the study design. TRIAL REGISTRATION: National Institute of Health Research Clinical Research Network portfolio IRAS ID: 272,250. Health Research Authority approval 18 October 2019. CLINICALTRIALS: gov, identifier NCT04270721, protocol ID RG_19196.

Cell shape characteristics of human skeletal muscle cells as a predictor of myogenic competency: A new paradigm towards precision cell therapy.

Skeletal muscle-derived cells (SMDC) hold tremendous potential for replenishing dysfunctional muscle lost due to disease or trauma. Current therapeutic usage of SMDC relies on harvesting autologous cells from muscle biopsies that are subsequently expanded in vitro before re-implantation into the patient. Heterogeneity can arise from multiple factors including quality of the starting biopsy, age and comorbidity affecting the processed SMDC. Quality attributes intended for clinical use often focus on minimum levels of myogenic cell marker expression. Such approaches do not evaluate the likelihood of SMDC to differentiate and form myofibres when implanted in vivo, which ultimately determines the likelihood of muscle regeneration. Predicting the therapeutic potency of SMDC in vitro prior to implantation is key to developing successful therapeutics in regenerative medicine and reducing implementation costs. Here, we report on the development of a novel SMDC profiling tool to examine populations of cells in vitro derived from different donors. We developed an image-based pipeline to quantify morphological features and extracted cell shape descriptors. We investigated whether these could predict heterogeneity in the formation of myotubes and correlate with the myogenic fusion index. Several of the early cell shape characteristics were found to negatively correlate with the fusion index. These included total area occupied by cells, area shape, bounding box area, compactness, equivalent diameter, minimum ferret diameter, minor axis length and perimeter of SMDC at 24 h after initiating culture. The information extracted with our approach indicates live cell imaging can detect a range of cell phenotypes based on cell-shape alone and preserving cell integrity could be used to predict propensity to form myotubes in vitro and functional tissue in vivo.

Pathway Of Low Anterior Resection syndrome relief after Surgery (POLARiS) feasibility trial protocol: a multicentre, feasibility cohort study with embedded randomised control trial to compare sacral neuromodulation and transanal irrigation to optimised conservative management in the management of major low anterior resection syndrome following rectal cancer treatment.

INTRODUCTION: Rectal cancer is common with a 60% 5-year survival rate. Treatment usually involves surgery with or without neoadjuvant chemoradiotherapy or adjuvant chemotherapy. Sphincter saving curative treatment can result in debilitating changes to bowel function known as low anterior resection syndrome (LARS). There are currently no clear guidelines on the management of LARS with only limited evidence for different treatment modalities. METHODS AND ANALYSIS: Patients who have undergone an anterior resection for rectal cancer in the last 10 years will be approached for the study. The feasibility trial will take place in four centres with a 9-month recruitment window and 12 months follow-up period. The primary objective is to assess the feasibility of recruitment to the POLARiS trial which will be achieved through assessment of recruitment, retainment and follow-up rates as well as the prevalence of major LARS.Feasibility outcomes will be analysed descriptively through the estimation of proportions with confidence intervals. Longitudinal patient reported outcome measures will be analysed according to scoring manuals and presented descriptively with reporting graphically over time. ETHICS AND DISSEMINATION: Ethical approval has been granted by Wales REC1; Reference 22/WA/0025. The feasibility study is in the process of set up. The results of the feasibility trial will feed into the design of an expanded, international trial. TRIAL REGISTRATION NUMBER: CT05319054.

Rectocele: Incidental or important? Observe or operate? Contemporary diagnosis and management in the multidisciplinary era.

BACKGROUND: More common in older women than younger women, rectoceles may be secondary to pelvic floor weakness and/or pelvic floor dysfunction with impaired rectal evacuation. Rectoceles may be small (<2 cm), medium (2-4 cm), or large (>4 cm). Arguably, large rectoceles are more likely to be associated with symptoms (e.g., difficult defecation). It can be challenging to ascertain the extent to which a rectocele is secondary to pelvic floor dysfunction and/or whether a rectocele, rather than associated pelvic floor dysfunction, is responsible for symptoms. Surgical repair should be considered when initial treatment measures (e.g., bowel modifying agents and pelvic floor biofeedback therapy) are unsuccessful. PURPOSE: We summarize the clinical features, diagnosis, and management of rectoceles, with an emphasis on outcomes after surgical repair. This review accompanies a retrospective analysis of outcomes after multidisciplinary, transvaginal rectocele repair procedures undertaken by three colorectal surgeons in 215 patients at a large teaching hospital in the UK. A majority of patients had a large rectocele. Some patients also underwent an anterior levatorplasty and/or an enterocele repair. All patients were jointly assessed, and some patients underwent surgery by colorectal and urogynecologic surgeons. In this cohort, the perioperative data, efficacy, and harms outcomes are comparable with historical data predominantly derived from retrospective series in which patients had a good outcome (67%-78%), symptoms of difficult defecation improved (30%-50%), and patients had a recurrent rectocele 2 years after surgery (17%). Building on these data, prospective studies that rigorously evaluate outcomes after surgical repair are necessary.

Faecal incontinence in adults.

Faecal incontinence, which is defined by the unintentional loss of solid or liquid stool, has a worldwide prevalence of ≤7% in community-dwelling adults and can markedly impair quality of life. Nonetheless, many patients might not volunteer the symptom owing to embarrassment. Bowel disturbances, particularly diarrhoea, anal sphincter trauma (obstetrical injury or previous surgery), rectal urgency and burden of chronic illness are the main risk factors for faecal incontinence; others include neurological disorders, inflammatory bowel disease and pelvic floor anatomical disturbances. Faecal incontinence is classified by its type (urge, passive or combined), aetiology (anorectal disturbance, bowel symptoms or both) and severity, which is derived from the frequency, volume, consistency and nature (urge or passive) of stool leakage. Guided by the clinical features, diagnostic tests and therapies are implemented stepwise. When simple measures (for example, bowel modifiers such as fibre supplements, laxatives and anti-diarrhoeal agents) fail, anorectal manometry and other tests (endoanal imaging, defecography, rectal compliance and sensation, and anal neurophysiological tests) are performed as necessary. Non-surgical options (diet and lifestyle modification, behavioural measures, including biofeedback therapy, pharmacotherapy for constipation or diarrhoea, and anal or vaginal barrier devices) are often effective, especially in patients with mild faecal incontinence. Thereafter, perianal bulking agents, sacral neuromodulation and other surgeries may be considered when necessary.

Total collagen content and distribution is increased in human colon during advancing age.

BACKGROUND: The effect of ageing on total collagen content of human colon has been poorly investigated. The aim of this study was to determine if ageing altered total collagen content and distribution in the human colon. METHODS: Macroscopically normal ascending colon was obtained at surgery from cancer patients (n = 31) without diagnosis of diverticular disease or inflammatory bowel disease. Masson's trichrome and Picrosirius red stains were employed to identify the total collagen content and distribution within the sublayers of the colonic wall for adult (22-60 years; 6 males, 6 females) and elderly (70 - 91years; 6 males, 4 female) patients. A hydroxyproline assay evaluated the total collagen concentration for adult (30-64 years; 9 male, 6 female) and elderly (66-91 years; 8 male, 8 female) patients. KEY RESULTS: Histological studies showed that the percentage mean intensity of total collagen staining in the mucosa, submucosa and muscularis externa was, respectively, 14(1.9) %, 74(3.2) % and 12(1.5) % in the adult ascending colon. Compared with the adults, the total collagen fibres content was increased in the submucosa (mean intensity; 163.1 ± 11.1 vs. 124.5 ± 7.8; P < 0.05) and muscularis externa (42.5 ± 8.0 vs. 20.6 ± 2.8; P < 0.01) of the elderly patients. There was no change in collagen content of the mucosa. The total collagen concentration was increased in the elderly by 16%. Sex-related differences were not found, and data were combined for analysis. CONCLUSIONS: Greater total collagen content was found in the submucosa and muscularis externa of the elderly human male and female colon. These changes may contribute to a possible loss of function with ageing.

Double-blinded randomised placebo controlled trial of enterosgel (polymethylsiloxane polyhydrate) for the treatment of IBS with diarrhoea (IBS-D).

OBJECTIVE: Irritable bowel syndrome with diarrhoea (IBS-D) is a common and challenging condition that significantly reduces quality of life. Enterosgel (polymethylsiloxane polyhydrate) is an intestinal adsorbent which sequesters harmful molecules and is safe and effective in acute infective diarrhoea. This randomised controlled multicentre trial aimed to investigate its safety and efficacy in patients with IBS-D. DESIGN: After a 2-week screening phase, participants were randomised into an 8-week double-blind phase, followed by an 8-week open-label and follow-up phase. Participants recorded stool consistency, pain and global symptoms in e-diaries and questionnaires. The primary outcome was the percentage of responders on a composite abdominal pain (≥30% decrease in the weekly score) and stool consistency (50% reduction in days per week with at least one stool of BSFS type 6 or 7) score during at least 4 weeks of the treatment period. RESULTS: 440 patients with IBS-D were randomised to the double-blind phase with 393 continuing to the open-label phase. The Primary outcome responder rate by intention-to-treat for enterosgel versus placebo was 37.4% vs 24.3% (OR 1.95, NNT 8, p=0.002). Enterosgel also improved stool consistency (48.5% vs 32.5%, p<0.0001) abdominal pain (53.3% vs 40.2%, p=0.003), stool frequency (treatment effect -0.32 (-0.62 to -0.02)) and urgency (treatment effect -0.59 (-0.85 to -0.33)). 60% of patients reported adequate relief of symptoms after open-label treatment. Adverse event frequency was similar in both groups, with no serious events attributable to enterosgel. CONCLUSION: Enterosgel is safe and effective in IBS-D, providing an alternative to the limited current treatment options. TRIAL REGISTRATION NUMBER: ISRCTN17149988.

Chronic anal pain: A review of causes, diagnosis, and treatment.

Chronic anal pain is difficult to diagnose and treat, especially with no obvious anorectal cause apparent on clinical examination. This review identifies 3 main diagnostic categories for chronic anal pain: local causes, functional anorectal pain, and neuropathic pain syndromes. Conditions covered within these categories include proctalgia fugax, levator ani syndrome, pudendal neuralgia, and coccygodynia. The signs, symptoms, relevant diagnostic tests, and main treatments for each condition are reviewed.

Abnormal Perception of Urge to Defecate: An Important Pathophysiological Mechanism in Women With Chronic Constipation.

INTRODUCTION: Although the association of absent or attenuated "call to stool" with constipation is well-recognized, no studies have systematically evaluated the perception of urge to defecate in a well-defined cohort of patients with chronic constipation (CC). METHODS: A prospective study of 43 healthy adult women and 140 consecutive adult women attending a tertiary center for investigation of CC. All participants completed a 5-day viscerosensory questionnaire, and all women with CC also underwent anorectal physiologic investigations. Normal urge perception and abnormal urge perception were defined using a Naive Bayes model trained in healthy women (95% having normal urge). RESULTS: In total, 181 toilet visits in healthy women and 595 in women with CC were analyzed. Abnormal urge perception occurred in 70 (50.0%) women with CC. In this group, the urge to defecate was more often experienced as abdominal sensation (69.3% vs 41.4%; P < 0.0001), and the viscerosensory referral area was 81% larger (median pixels anterior: 1,849 vs 1,022; P < 0.0001) compared to women with CC and normal urge perception. Abnormal (vs normal) urge in women with CC was associated with more severe constipation (Cleveland Clinic constipation score: 19 vs 15 P < 0.0001), irritable bowel syndrome (45.7% vs 22.9% P < 0.0001), and a functional evacuation disorder on defecography (31.3% vs 14.3% P = 0.023). A distinct pattern of abnormal urge was found in women with CC and rectal hyposensitivity. DISCUSSION: Abnormal urge perception was observed in 50% of women with CC and was frequently described as abdominal sensation, supporting the concept that sensory dysfunction makes an important contribution to the pathophysiology of constipation.

Systematic review and meta-analysis of anal motor and rectal sensory dysfunction in male and female patients undergoing anorectal manometry for symptoms of faecal incontinence.

AIM: Manometry is the best established technique to assess anorectal function in faecal incontinence. By systematic review, pooled prevalences of anal hypotonia/hypocontractility and rectal hypersensitivity/hyposensitivity in male and female patients were determined in controlled studies using anorectal manometry. METHODS: Searches of MEDLINE and Embase were completed. Screening, data extraction and bias assessment were performed by two reviewers. Meta-analysis was performed based on a random effects model with heterogeneity evaluated by I2 . RESULTS: Of 2116 identified records, only 13 studies (2981 faecal incontinence patients; 1028 controls) met the inclusion criteria. Anal tone was evaluated in 10 studies and contractility in 11; rectal sensitivity in five. Only three studies had low risk of bias. Pooled prevalence of anal hypotonia was 44% (95% CI 32-56, I2 = 96.35%) in women and 27% (95% CI 14-40, I2 = 94.12%) in men. The pooled prevalence of anal hypocontractility was 69% (95% CI 57-81; I2 = 98.17%) in women and 36% (95% CI 18-53; I2 = 96.77%) in men. Pooled prevalence of rectal hypersensitivity was 10% (95% CI 4-15; I2 = 80.09%) in women and 4% (95% CI 1-7; I2 = 51.25%) in men, whereas hyposensitivity had a pooled prevalence of 7% (95% CI 5-9; I2 = 0.00%) in women compared to 19% (95% CI 15-23; I2 = 0.00%) in men. CONCLUSIONS: The number of appropriately controlled studies of anorectal manometry is small with fewer still at low risk of bias. Results were subject to gender differences, wide confidence intervals and high heterogeneity indicating the need for international collective effort to harmonize practice and reporting to improve certainty of diagnosis.