Artificial Intelligence in Coloproctology: A Review of Emerging Technologies and Clinical Applications.

Artificial intelligence (AI) has emerged as a transformative tool across several specialties, namely gastroenterology, where it has the potential to optimize both diagnosis and treatment as well as enhance patient care. Coloproctology, due to its highly prevalent pathologies and tremendous potential to cause significant mortality and morbidity, has drawn a lot of attention regarding AI applications. In fact, its application has yielded impressive outcomes in various domains, colonoscopy being one prominent example, where it aids in the detection of polyps and early signs of colorectal cancer with high accuracy and efficiency. With a less explored path but equivalent promise, AI-powered capsule endoscopy ensures accurate and time-efficient video readings, already detecting a wide spectrum of anomalies. High-resolution anoscopy is an area that has been growing in interest in recent years, with efforts being made to integrate AI. There are other areas, such as functional studies, that are currently in the early stages, but evidence is expected to emerge soon. According to the current state of research, AI is anticipated to empower gastroenterologists in the decision-making process, paving the way for a more precise approach to diagnosing and treating patients. This review aims to provide the state-of-the-art use of AI in coloproctology while also reflecting on future directions and perspectives.

Feasibility of IAPWG protocol in performing high-definition three-dimensional anorectal manometry: A prospective, multicentric italian study.

BACKGROUND: The International Anorectal Physiology Working Group (IAPWG) suggests a standardized protocol to perform high-resolution anorectal manometry. The applicability and possible limitations of the IAPWG protocol in performing three-dimensional high-definition anorectal manometry (3D-ARM) have still to be extensively evaluated. METHODS: The IAPWG protocol was applied in performing 3D-ARM. Anorectal manometry (ARM) and a balloon expulsion test (BET) were performed according to IAPGW protocol in 290 patients. KEY RESULTS: A total of 84 males and 206 females (mean age 57.1 ± 15.7 years) were enrolled in six Italian centers. The reasons for which the patients were sent to perform 3D-ARM were: constipation (53.1%), fecal incontinence (26.9%), anal pain (3.1%), postsurgical (3.8%) and presurgical evaluation (4.8%), prolapse (3.4%), anal fissure (2.8%), and other (2.1%). Due to organic and functional conditions (low rectal anterior resections, rectal prolapses, and J-pouch after colectomy), we were unable to perform a complete 3D-ARM on six patients. Overall, a complete 3D-ARM and BET following IAPWG protocol was carried out in 284 patients (97.9%). The following were recorded: rest pressure (81.9 ± 32.0 mmHg) and length of the anal sphincter (37.0 ± 6.2 cm), maximum anal squeeze pressure (201.6 ± 81.3 mmHg), squeeze duration (22.0 ± 8.8 s), maximum rectal (48.7 ± 41.0 mmHg) and minimum anal pressure (73.3 ± 36.5 mmHg) during push, presence/absence of a dyssynergic pattern, cough reflex and rectal sensations (first constant sensation 48.4 ± 29.5 mL, desire to defecate 83.7 ± 52.1 mL, and maximum tolerated volume 149.5 ± 72.6 mL), and presence/absence of rectoanal inhibitory reflex. Mean 3D-ARM registration time was 14 min 7 s ± 3 min 12 s. CONCLUSIONS: This is the first multicentric study that evaluates the applicability of the IAPWG protocol in 3D-ARM performed in different manometric laboratories (both gastroenterological and surgical). The IAPWG protocol was easy to perform and was not time consuming. A diagnosis according to the London Classification was easily obtained in most patients in which 3D-ARM was carried out. No clear limitations to the applicability of the IAPWG protocol were detected.

Evaluation of conventional anorectal manometry and biofeedback therapy in adolescents with functional constipation.

OBJECTIVE: The aim was to evaluate the outcomes of conventional anorectal manometry (ARMM) testing and biofeedback therapy in adolescents with functional constipation. METHODS: A retrospective analysis of ARMM findings in patients aged 10-18 years with intractable constipation over a 4-year period was conducted. RESULTS: Of the 41 patients (mean age, 13.5±2.44 years) included, 20 (48.7%) were male. Rectoanal inhibitory reflex (RAIR) was positive in all patients. Group 1 had 31 patients with dyssynergic defecation (DD) and Group 2 had 10 patients without DD. Anal canal resting pressure, squeeze test pressure, rectal defecation pressure, and first and urge sensation volumes were similar between the groups. Maximum tolerated volume and the relaxation percentage of RAIR were higher in Group 1 than in Group 2 (p<0.05). Among 31 patients referred for biofeedback therapy, 8 (25.6%) completed the program with complete resolution of their symptoms. The mean follow-up period for these patients was 21±14.7 months. CONCLUSION: DD is relatively common in patients with psychosocial adjustment disorders, and it can be diagnosed via ARMM. Despite the low rate of adherence to the therapy in the presented series, biofeedback therapy was highly effective in resolving the symptoms including soiling.

Correlation of Digital Rectal Examination and Anorectal Manometry with Patient-Reported Outcomes Among Women with Fecal Incontinence.

INTRODUCTION AND HYPOTHESIS: Standardized digital rectal examination (DRE) correlates with anorectal manometry (ARM) measures. However, less is known about the relationship between DRE/ARM measures and patient-reported outcomes (PROs), especially among women with fecal incontinence (FI). Our aims were to evaluate associations between DRE and ARM measures and compare PROs with diagnostic evaluation measures for women with FI. METHODS: We analyzed data from the parent clinical trial, Controlling Anal incontinence by Performing Anal exercises with Biofeedback or Loperamide (CAPABLe). We pooled data from randomized women who completed standardized ARM, DRE, and validated PROs at baseline and 12 and 24 weeks post-treatment initiation. PROs included FI severity, impact on quality of life, and bowel diary data. We analyzed ARM pressure and volume data and DRE using the Digital Rectal Examination Scoring System (DRESS) resting and squeeze mean scores. We used Spearman Rank Correlation to measure associations between the ARM measures and mean DRESS scores, and between PROs and ARM/DRESS scores. RESULTS: Among 291 randomized women with ARM and DRE data, the correlation between DRESS and ARM resting measures was 0.196 (p<0.001) and between squeeze measures was 0.247 (p<0.001). At most timepoints, PROs more consistently correlated with squeeze ARM pressures and squeeze DRESS scores than resting measures. CONCLUSIONS: We found weak correlations between ARM and DRE measures and between those measures and PROs. Although DRE and ARM are commonly used diagnostic measures among women with FI, the weak correlations with patient-reported symptoms raises questions about their utility in clinical care.

Effects on anorectal function of endoscopic submucosal dissection for rectal tumors involving the dentate line.

OBJECTIVE: Endoscopic submucosal dissection (ESD) is a specific procedure that uses an electrosurgical knife for en-bloc resectioning large tumors. However, no study has examined the effect of ESD on the defecation function of patients with rectal tumors. We aimed to investigate the potential effects caused by ESD by analyzing changes in the morphology and movement of the anorectum pre- and post-ESD. METHODS: This prospective observational study included 11 patients with anorectal tumors who underwent ESD between April 2020 and February 2022. Pre-ESD assessments included anorectal manometry and defecography. Post-ESD assessments were conducted 2 months later, including anorectal manometry, defecography, and proctoscopy for ulcer and stenosis evaluation. RESULTS: The median patient age was 73 years, including seven males and four females. Eight patients (73%) had a tumor in the lower rectum, and the extent of resection was less than 50% of the rectal lumen. Resection reached the dentate line in six cases (55%). In the patients with post-ESD mucosal defects involving the dentate line, the median of functional anal canal length significantly decreased from (3.4 cm pre-ESD to 2.8 cm post-ESD, p = 0.04). Defecography revealed one case with incomplete evacuation (<50%) and incontinence post-ESD. Interestingly, patients with pre-existing rectoceles noted resolution of lesions post-ESD. None of the patients reported daily constipation or fecal incontinence. CONCLUSIONS: While rectal ESD is unlikely to cause significant real-world defecation difficulties, alterations in rectal and anal canal morphology and function may occur if the dentate line is involved in the resection range.

Anorectal physiology and colonic motility in children with a history of tethered cord syndrome.

OBJECTIVES: The understanding of the impact of tethered cord syndrome (TCS) on the physiology of the colorectal area is limited. Our aim was to describe anorectal and colonic motility in children with TCS and compare the findings to those of children with functional constipation (FC). METHODS: We conducted a retrospective review of children with TCS who had an anorectal manometry (ARM) performed at our institution from January 2011 to September 2023. We recorded demographics, medical and surgical history, clinical symptoms, and treatment at time of ARM, ARM findings (resting pressure, push maneuver, rectal sensation, rectoanal inhibitory reflex [RAIR], and RAIR duration), and the final interpretation of colonic manometry (CM) if performed. We identified age and sex-matched control groups of children with FC. RESULTS: We included 24 children with TCS (50% female) who had ARM testing (median age at ARM 6.0 years, interquartile range 4.0-11.8 years). All children had constipation at time of ARM. Nineteen children had detethering surgery before ARM was performed. No significant differences in ARM parameters were found between children who had detethering surgery before ARM and children with FC. Among the 24 children, 14 also had a CM performed (13/14 after detethering surgery). No significant differences in colonic motility were found between children with a history of TCS and children with FC. CONCLUSIONS: Anorectal physiology and colonic motility are similar between children with a history of TCS and children with FC, suggesting that the underlying pathophysiology of defecatory disorders in children with and without history of TCS is similar.

Anorectal Manometry in Pediatric Colorectal Surgical Care.

BACKGROUND: Pediatric colorectal specialists care for patients with a variety of defecation disorders. Anorectal (AR) manometry testing is a valuable tool in the diagnosis and management of these children. This paper provides a summary of AR manometry techniques and applications as well as a review of AR manometry findings in pediatric patients with severe defecation disorders referred to a pediatric colorectal center. This is the first study describing multi-year experience using a portable AR manometry device in pediatric patients. METHODS: An electronic medical record review was performed (1/2018 to 12/2023) of pediatric patients with defecation disorders who had AR manometry testing. Demographics, diagnostic findings, and outcomes are described. KEY RESULTS: A total of 297 unique patients (56.9% male, n = 169) had AR manometry testing. Of these, 72% (n = 188) had dyssynergic defecation patterns, of which 67.6% (n = 127) had fecal soiling prior to treatment. Pelvic rehabilitation (PR) was administered to 35.4% (n = 105) of all patients. A total of 79.5% (n = 58) of the 73 patients that had fecal soiling at initial presentation and completed PR with physical therapy and a bowel management program were continent after therapy. AR manometry was well tolerated, with no major complications. CONCLUSIONS: AR manometry is a simple test that can help guide the management of pediatric colorectal surgical patients with defecation disorders. As a secondary finding, PR is a useful treatment for patients with dyssynergic stooling.

Current practice in the care of children with functional constipation: What is the hold up?

OBJECTIVES: For children with intractable functional constipation (FC), there are no evidence-based guidelines for subsequent evaluation and treatment. Our objective was to assess the practice patterns of a large, international cohort of pediatric gastroenterologists. METHODS: We administered a survey to physicians who attended the 2nd World Congress of Pediatric Neurogastroenterology and Motility held in Columbus, Ohio (USA) in September 2023. The survey included 29 questions on diagnostic testing, nonpharmacological and pharmacological treatment, and surgical options for children with intractable FC. RESULTS: Ninety physicians from 18 countries completed the survey. For children with intractable FC, anorectal manometry was the most commonly used diagnostic test. North American responders were more likely than Europeans to use stimulant laxatives (97% vs. 77%, p = 0.032), prosecretory medications (69% vs. 8%, p < 0.001), and antegrade continence enemas (ACE; 83% vs. 46%, p = 0.009) for management. Europeans were more likely than North Americans to require colonic transit testing before surgery (85% vs. 30%, p < 0.001). We found major differences in management practices between Americans and the rest of the world, including use of prosecretory drugs (73% vs. 7%, p < 0.001), anal botulinum toxin injections (81% vs. 58%, p = 0.018), ACE (81% vs. 58% p = 0.018), diverting ileostomies (56% vs. 26%, p = 0.006), and colonic resections (42% vs. 16%, p = 0.012). No differences were found when respondents were compared by years of experience. CONCLUSIONS: Practice patterns in the evaluation and treatment of children with intractable FC differ widely among pediatric gastroenterologists from around the world. A clinical guideline regarding diagnostic testing and surgical decision-making is needed.

Analysis of factors that indicated surgery in 400 patients submitted to a complete diagnostic workup for obstructed defecation syndrome and rectal prolapse using a supervised machine learning algorithm.

BACKGROUND: Patient selection is extremely important in obstructed defecation syndrome (ODS) and rectal prolapse (RP) surgery. This study assessed factors that guided the indications for ODS and RP surgery and their specific role in our decision-making process using a machine learning approach. METHODS: This is a retrospective analysis of a long-term prospective observational study on female patients reporting symptoms of ODS who underwent a complete diagnostic workup from January 2010 to December 2021 at an academic tertiary referral center. Clinical, defecographic, and other functional tests data were assessed. A supervised machine learning algorithm using a classification tree model was performed and tested. RESULTS: A total of 400 patients were included. The factors associated with a significantly higher probability of undergoing surgery were follows: as symptoms, perineal splinting, anal or vaginal self-digitations, sensation of external RP, episodes of fecal incontinence and soiling; as physical examination features, evidence of internal and external RP, rectocele, enterocele, or anterior/middle pelvic organs prolapse; as defecographic findings, intra-anal and external RP, rectocele, incomplete rectocele emptying, enterocele, cystocele, and colpo-hysterocele. Surgery was less indicated in patients with dyssynergia, severe anxiety and depression. All these factors were included in a supervised machine learning algorithm. The model showed high accuracy on the test dataset (79%, p < 0.001). CONCLUSIONS: Symptoms assessment and physical examination proved to be fundamental, but other functional tests should also be considered. By adopting a machine learning model in further ODS and RP centers, indications for surgery could be more easily and reliably identified and shared.

Effect of neoadjuvant chemoradiation on anorectal function assessed with anorectal manometry: A systematic review and meta-analysis.

AIM: Improvement in oncological survival for rectal cancer increases attention to anorectal dysfunction. Diagnostic questionnaires can evaluate quality of life but are subjective and dependent on patients' compliance. Anorectal manometry can objectively assess the continence mechanism and identify functional sphincter weakness and rectal compliance. Neoadjuvant chemoradiotherapy is presumed to affect anorectal function. We aim to assess anorectal function in rectal cancer patients who undergo total mesorectal excision, with or without neoadjuvant chemoradiation, using anorectal manometry measurements. METHOD: MEDLINE, Embase, and Cochrane databases were searched for studies comparing perioperative anorectal manometry between neoadjuvant chemoradiation and upfront surgery for rectal cancers. Primary outcomes were resting pressure, squeeze pressure, sensory threshold volume and maximal tolerable volume. RESULTS: Eight studies were included in the systematic review, of which seven were included for metanalysis. 155 patients (45.3%) had neoadjuvant chemoradiation before definitive surgery, and 187 (54.6%) underwent upfront surgery. Most patients were male (238 vs. 118). The standardized mean difference of mean resting pressure, mean and maximum squeeze pressure, maximum resting pressure, sensory threshold volume, and maximal tolerable volume favored the upfront surgery group but without statistical significance. CONCLUSION: Currently available evidence on anorectal manometry protocols failed to show any statistically significant differences in functional outcomes between neoadjuvant chemoradiation and upfront surgery. Further large-scale prospective studies with standardized neoadjuvant chemoradiation and anorectal manometry protocols are needed to validate these findings.

High-Resolution Anorectal Manometry as a Screening Tool for Hirschsprung's Disease: A Comprehensive Retrospective Analysis.

Hirschsprung's disease (HD) is characterized by a congenital absence of enteric ganglion cells in the intestine, posing challenges in diagnosis, particularly in pediatric patients. The gold standard, rectal suction biopsy (RSB), carries risks, prompting an exploration of non-invasive alternatives such as high-resolution anorectal manometry (HR-ARM) for HD screening. We conducted a retrospective analysis of 136 patients suspected of HD between 2018 and 2022, which were stratified into three age groups: ≤12 months, ≤24 months, and >24 months. Criteria for suspicion included delayed meconium passage, unresponsive chronic constipation, and abnormal prior test results. HR-ARM, supplemented by additional tests, confirmed 16 HD cases. HR-ARM exhibited 93.75% sensitivity, 89.47% specificity, 99.03% negative predictive value (NPV), and 55.56% positive predictive value (PPV). Notably, HR-ARM consistently performed well in patients ≤ 2 years old but demonstrated reduced efficacy in older children, which was likely due to complications from chronic constipation. This study underscores HR-ARM's promise as a non-invasive HD screening tool, especially in younger patients. However, its limitations in older children warrant consideration. Establishing standardized protocols, particularly for assessing the recto-anal inhibitory reflex, is crucial. Further research is imperative to optimize HR-ARM's diagnostic role across varied age groups in HD assessment.

Short-term clinical and manometric outcomes of percutaneous tibial nerve stimulation for faecal incontinence: a large single-centre series.

BACKGROUND: Faecal incontinence (FI) is common, with a significant impact on quality of life. Percutaneous tibial nerve stimulation (PTNS) is a therapy for FI; however, its role has recently been questioned. Here we report the short-term clinical and manometric outcomes in a large tertiary centre. METHODS: A retrospective review of a prospective PTNS database was performed, extracting patient-reported FI outcome measures including bowel diary, the St Marks's Incontinence Score (SMIS) and Manchester Health Questionnaire (MHQ). Successful treatment was > 50% improvement in symptoms, whilst a partial response was 25-50% improvement. High-resolution anorectal manometry (HRAM) results before and after PTNS were recorded. RESULTS: Data were available from 135 patients [119 (88%) females; median age: 60 years (range: 27-82years)]. Overall, patients reported a reduction in urge FI (2.5-1) and passive FI episodes (2-1.5; p < 0.05) alongside a reduction in SMIS (16.5-14) and MHQ (517.5-460.0; p < 0.001). Some 76 (56%) patients reported success, whilst a further 20 (15%) reported a partial response. There were statistically significant reductions in rectal balloon thresholds and an increase in incremental squeeze pressure; however, these changes were independent of treatment success. CONCLUSION: Patients report PTNS improves FI symptoms in the short term. Despite this improvement, changes in HRAM parameters were independent of this success. HRAM may be unable to measure the clinical effect of PTNS, or there remains the possibility of a placebo effect. Further work is required to define the role of PTNS in the treatment of FI.

Usefulness of Preoperative Anorectal Manometry for Ostomy Closure: A Cross-sectional Study / Utilidad de la manometría anorrectal prequirúrgica para el cierre de ostomías: un estudio de corte transversal

Abstract Introduction: For several reasons, a patient may be taken to a colostomy for closure as soon as possible. However, their treatment may vary, and predicting adequate continence after colostomy closure can be difficult. The objective is to characterize preoperative manometry because, in Colombia, few cases describe its usefulness. Methods: A descriptive cross-sectional study of adult patients treated in two gastroenterology centers in Colombia between 2018 and 2020. Results: Of 316 patients, 13 were indicated manometry before colostomy closure, predominantly women (69%), with an average age of 51.69 years (standard deviation: 24.18). When evaluating the basal pressures of the anal sphincter, we noted 68% hypotonia, 16% hypertonia, and 16% normal pressures. The voluntary contraction test was abnormal in 25%, and a pattern of dyssynergic defecation was observed in 30%, all with type III patterns. The inhibitory rectoanal reflex was present in 92%, with an abnormal balloon expulsion test in 100% of patients. More than 70% of patients persisted with the colostomy in situ after the first year of construction and 30% beyond 36 months. Conclusions: The present study posits questions about the cost-effectiveness of anorectal manometry before colostomy closure, which requires corroboration by studies with more patients and more robust methodological designs.

Resumen Introducción: Hay varias razones por las que un paciente puede ser llevado a una colostomía con el objetivo de cerrarla lo antes posible, pero su tratamiento puede variar, y predecir una adecuada continencia posterior al cierre de la colostomía puede ser difícil. Se plantea como objetivo realizar una caracterización de la manometría prequirúrgica debido a que en Colombia hay pocos casos que describan su utilidad. Metodología: Estudio observacional descriptivo de corte transversal en pacientes adultos atendidos en dos centros de gastroenterología en Colombia entre el 2018 y el 2020. Resultados: De 316 pacientes, 13 tenían indicación de manometría previo a cierre de colostomía, predominantemente mujeres (69%), con una edad promedio de 51,69 años (desviación estándar: 24,18). Al evaluar las presiones basales del esfínter anal, se evidenció 68% de hipotonía, 16% de hipertonía y 16% de presiones normales. La prueba de contracción voluntaria fue anormal en el 25%, se observó un patrón de disinergia defecatoria en el 30%, todas con patrón tipo III. El reflejo rectoanal inhibitorio estuvo presente en el 92%, con prueba de expulsión de balón anormal en el 100% de los pacientes. Más del 70% de los pacientes persistían con la colostomía in situ después del primer año de su construcción y 30% más allá de 36 meses. Conclusiones: El presente estudio genera cuestionamientos acerca la costo-efectividad de la manometría anorrectal previa al cierre de colostomía, lo cual requiere ser corroborado por estudios con una mayor cantidad de pacientes y diseños metodológicos más robustos.

Relationship of Age and Gender to Motility Test Results and Symptoms in Patients with Chronic Constipation.

BACKGROUND/AIMS: Patients with chronic constipation (CC) exhibit symptoms and functional abnormalities upon testing, but their relationship to age and gender is unclear. We assessed age- and gender-related differences in symptoms, colon transit time, and anorectal motility, sensation, and expulsion. PATIENTS AND METHODS: Retrospective, post hoc data analysis of patients with CC, who underwent Wireless Motility Capsule (WMC), High-Resolution Anorectal Manometry (HR-ARM), Balloon Expulsion Test (BET) and Rectal Sensory Testing (RST). Clinical assessment was made by questionnaires. Standard WMC criteria for colonic transit time (CTT) and the London classification was used for HR-ARM analyses, and regression plots between age, gender, CTT, HR-HRM, RST and BET were calculated. RESULTS: We studied 75 women and 91 men. Abdominal pain, infrequent defecation, incomplete evacuation, defecatory straining, and multiple motility and anorectal function abnormalities were common. Abdominal pain was least frequently, and straining was most frequently associated with a motility abnormality. For each symptom, the highest prevalence was associated with failed BET. There was a significant increase in CTT with age only in men (p = 0.0006). In men, for each year of age there was a CTT increase of 1.02 h. The prevalence of abdominal pain and incomplete evacuation for females was significantly higher than that for males (both P < 0.05). The prevalence of low anal squeeze pressure for females was significantly higher than that for males, and the prevalence of poor rectal sensation for males was significantly higher than that for females (both P < 0.05). A significant decrease in basal anal and squeeze pressures with age occurred in women (p < 0.0001); an increase in age of one year was associated with a decrease in anal base pressure of 1.2 mmHg. Abnormal CTT and HR-ARM tests were associated with increased symptom frequency, but not severity. CONCLUSIONS: There are significant age- and gender-related differences in symptoms, CTT, and HR-HRM parameters, rectal sensation, and expulsion, that may influence the multifaceted management of constipation.

Use of a footstool improves rectal balloon expulsion in some patients with defecatory disorders.

BACKGROUND: Whether patients with defecatory disorders (DDs) with favorable response to a footstool have distinctive anorectal pressure characteristics is unknown. We aimed to identify the clinical phenotype and anorectal pressure profile of patients with DDs who benefit from a footstool. METHODS: This is a retrospective review of patients with high resolution anorectal manometry (HR-ARM) and balloon expulsion test (BET) from a tertiary referral center. BET was repeated with a 7-inch-high footstool in those who failed it after 120 s. Data were compared among groups with respect to BET results. KEY RESULTS: Of the 667 patients with DDs, a total of 251 (38%) had failed BET. A footstool corrected BET in 41 (16%) of those with failed BET. Gender-specific differences were noted in anorectal pressures, among patients with and without normal BET, revealing gender-based nuances in pathophysiology of DDs. Comparing patients who passed BET with footstool with those who did not, the presence of optimal stool consistency, with reduced instances of loose stools and decreased reliance on laxatives were significant. Additionally, in women who benefited from a footstool, lower anal pressures at rest and simulated defecation were observed. Independent factors associated with a successful BET with a footstool in women included age <50, Bristol 3 or 4 stool consistency, lower anal resting pressure and higher rectoanal pressure gradient. CONCLUSION & INFERENCES: Identification of distinctive clinical and anorectal phenotype of patients who benefited from a footstool could provide insight into the factors influencing the efficacy of footstool utilization and allow for an individualized treatment approach in patients with DDs.

Rectal Sensory and Compliance Testing: A Method Comparison Study between High-Resolution Anorectal Manometry and Barostat Investigations.

Abnormal visceral perception and motor function are often observed in patients with fecal incontinence, evacuation disorders and irritable bowel syndrome. The international anorectal physiology working group has proposed a standardization for anorectal function assessment, where rectal sensitivity testing is performed using an elastic balloon attached to a high-resolution anorectal manometry (HRAM) catheter. Rectal compliance, another component of rectal function evaluation, is a pressure-volume relationship that refers to the rectum's ability to stretch and expand as it receives and holds fecal matter. There are no data available regarding the possibility of compliance testing using HRAM, although this is theoretically possible by correcting for the elastic balloon's intrinsic properties. The gold standard for measurement of visceral sensitivity and compliance is the rectal barostat, according to the procedure described by the European COST action GENIEUR group. Data on the agreement between the two different procedures are scarce. Hence, we performed a comparative study of the HRAM and barostat investigations in 26 healthy individuals. We hypothesized that by inflating the balloon before the examination, rectal compliance can be measured with HRAM investigations, and we examined correlations and levels of agreement between the methods. Our results demonstrate that assessing rectal compliance with HRAM is technically possible; however, a strong correlation with the rectal barostat was only observed at the maximum tolerable volume (Spearman's rho = 0.7, p = 0.02). We only found moderate correlations (Spearman's rho = 0.562, p = 0.019) for compliance according to the barostat methodology and for rectal sensibility testing (Spearman's rho = 0.57, p = 0.03 for maximum tolerable volume). Bland-Altman plots showed poor levels of agreement between the methods. We conclude that HRAM and the rectal barostat cannot be used interchangeably for compliance or sensitivity assessments. We suggest the development of a non-elastic balloon with a fixed size and shape to assess rectal sensory function and compliance in HRAM testing.

Comparison of etiological and physiological characteristics of fecal incontinence in men and women.

Fecal incontinence (FI) is often underreported and underestimated in men. Our aims were to clarify the causes and the physiological characteristics of FI in men and to underline the differences between etiological and physiological factors in men and women diagnosed with FI. The study cohort encompassed 200 men and 200 women who underwent anatomical and physiological evaluation for FI in a tertiary referral center specializing in pelvic floor disorders. All patients underwent endoanal ultrasound and anorectal manometry. Evacuation proctography was performed in some patients. Demographic, medical, anatomical, and physiological parameters were compared between the two study groups. Urge incontinence was the most frequent type of FI in both genders. In men, anal fistula, history of anal surgeries, rectal tumors, and pelvic radiotherapy were common etiologic factors, whereas history of pelvic surgeries was more common in women. Associated urinary incontinence was reported more frequently by women. External anal sphincter defects, usually anterior, were more common in women (M: 1.5%, F: 24%, P < 0.0001), whereas internal anal sphincter defect prevalence was similar in men and women (M: 6%, F: 12%, P = 0.19). Decreased resting and squeeze pressures were less common in men (M: 29%, F: 46%, P < 0.0001: M: 44%, F: 66%, P < 0.0001). The incidence of rectal hyposensitivity was higher in men (M: 11.1%, F: 2.8%, P < 0.0001), whereas rectal hypersensitivity was higher in women (M: 5.8%, F: 10.8%, P < 0.0001). Anorectal dyssynergia was more common in men (M: 66%, F: 37%, P < 0.0001). Significantly different etiological factors and physiological characteristics for FI were found in men. Acknowledging these differences is significant and may yield better treatment options.NEW & NOTEWORTHY Fecal incontinence (FI) in men has different etiological factors when compared with women. The prevalence of internal anal sphincter defect among men with FI was similar to women. Different manometric measurements were found among men with FI: decreased anal pressures were less common among men, whereas rectal hyposensitivity and anorectal dyssynergia were more common among men.

Obesity Is Associated with Altered Rectal Sensitivity in Chronic Constipation.

BACKGROUND: Defecation dysfunction may contribute to chronic constipation (CC), but the impact of obesity on anorectal physiology in CC remains unclear. We aimed to evaluate the relationship between obesity and anorectal function on physiologic testing in patients presenting with CC. METHODS: This was a retrospective cohort study of consecutive adults who underwent high resolution anorectal manometry (HRAM) at a tertiary center for CC. Patient demographics, clinical history, surgical/obstetric history, medications, and HRAM results were reviewed. Patients were classified into obese (BMI > 30 kg/m2) vs non-obese (BMI < 30 kg/m2) groups at the time of HRAM. Fisher-exact/student t-test for univariate analyses and general linear regression for multivariable analysis were performed. RESULTS: 383 adults (mean 50.3 years; 85.8% female) with CC were included. On HRAM, patients with obesity had lower anal sphincter resting tone (37.3 vs 48.5 mmHg, p = 0.005) and maximum squeeze pressure (104.8 mmHg vs 120.0 mmHg, p = 0.043). No significant differences in dyssynergia (61% vs 53%, p = 0.294) and failed balloon expulsion (18% vs 25%, p = 0.381) were found between obese and non-obese groups. On balloon distention testing, the maximum tolerated (163.5 vs 147.6 mL, p = 0.042) and urge sensation (113.9 vs 103.7 mL, p = 0.048) volumes were significantly increased among patients with obesity. After adjusting for potential confounders, obesity remained independently associated with increased maximum tolerated volume (ß-coefficient 13.7, p = 0.049). CONCLUSION: Obesity was independently associated with altered rectal sensitivity among patients with CC. Altered rectal sensation may play an important role in CC among patients with obesity. Anorectal physiology testing should be considered to understand the pathophysiology and guide management.

Digital Rectal Exams Are Infrequently Performed Prior to Anorectal Manometry.

BACKGROUND: Digital rectal examination should be performed prior to anorectal manometry; however, real-world data is lacking. AIMS: Characterize real world rates of digital rectal and their sensitivity for detecting dyssynergia compared to anorectal manometry and balloon expulsion test. METHODS: A retrospective single-center study was conducted to examine all patients who underwent anorectal manometry for chronic constipation between 2021 and 2022 at one tertiary center with motility expertise. Primary outcomes consisted of the rate of digital rectal exam prior to anorectal manometry; and secondary outcomes included the sensitivity of digital rectal exam for dyssynergic defecation. RESULTS: Only 42.3% of 142 patients had digital rectal examinations prior to anorectal manometry. Overall sensitivity for detecting dyssynergic defecation was 46.4%, but significantly higher for gastroenterology providers (p = .004), and highest for gastroenterology attendings (82.6%). CONCLUSIONS: Digital rectal examination is infrequently performed when indicated for chronic constipation. Sensitivity for detecting dyssynergic defecation may be impacted by discipline and level of training.

High-resolution anorectal manometry for diagnosing obstructed defecation syndrome associated with moderate rectocele compared to healthy individuals.

BACKGROUND: Few studies have investigated healthy female individuals (HFI) and those with obstructed defecation syndrome associated with moderate rectocele in women (MRW), identified using three-dimensional high-resolution anorectal manometry (3D HRAM) parameters that correlate with age stratification. OBJECTIVE: We aimed to explore the clinical diagnostic values of the MRW and HFI groups using 3D HRAM parameters related to age stratification. METHODS: A prospective non-randomized controlled trial involving 128 cases from the MRW (treatment group, 68 cases) and HFI (control group, 60 cases) groups was conducted using 3D HRAM parameters at Tianjin Union Medical Center between January 2017 and June 2022, and patients were divided into two subgroups based on their ages: the ≥50 and < 50 years subgroups. RESULTS: Multivariate binary logistic regression analysis showed that age (P = 0.024) and rectoanal inhibitory reflex (P = 0.001) were independent factors affecting the disease in the MRW group. Compared to the HFI group, the receiver operating characteristic (ROC) curve demonstrated that the 3D HRAM parameters exhibited a higher diagnostic value for age (Youden index = 0.31), urge to defecate (Youden index = 0.24), and rectoanal pressure differential (Youden index = 0.21) in the MRW group. CONCLUSIONS: Compared to the HFI group, the ROC curve of the 3D HRAM parameters suggests that age, urge to defecate, and rectoanal pressure differential in the MRW group have a significant diagnostic value. Because the Youden index is lower, 3D HRAM cannot be considered the gold standard method for diagnosing MRW.