Understanding the physiology of human defaecation and disorders of continence and evacuation

Review document of the Spanish Association of Neurogastroenterology and Motility on the management of opioid-induced constipation

Opioid-induced constipation (OIC) is a rising problem due to the progressive increase in opioid prescription. In contrast to functional constipation, opioid-induced constipation is not a functional gut disorder but a side effect of opioid use. Opioids produce constipation due to a decrease in gastrointestinal motility and a reduction in gastrointestinal secretions. The treatment of OIC focuses on three basic pillars: optimizing opioid drug indication, preventing constipation onset, and treating constipation should it develop. As with any other cause of constipation, lifestyle adjustments and laxatives should be the first-line option in the pharmacological management of OIC. Osmotic laxatives such as polyethylene glycol (PEG) are the agents of choice. PEG is inert and is neither fermented nor absorbed in the gastrointestinal tract. Furthermore, it has broad clinical applicability due to its favourable safety profile. If first-line treatments fail, peripheral μ-opioid receptor antagonists (PAMORA) are the drugs of choice. They reduce the peripheral effects of OIC with a minimal potential to diminish analgesia or induce a centrally mediated withdrawal syndrome. Different PAMORA are available in the market both for oral and subcutaneous administration, with demonstrated efficacy for the management of OIC in different clinical trials.

Letter: Light in the lumen-The expanding role of intestinal ultrasound for functional symptoms in inflammatory bowel disease. Authors' reply

This article is linked to Aliu et al papers. To view these articles, visit https://doi.org/10.1111/apt.17988 and https://doi.org/10.1111/apt.18161

Centrally Distributed Adiposity as a Modifiable Risk Factor for Fecal Incontinence: United States Population-based Analysis

BACKGROUND AND AIMS

Fecal incontinence (FI) is highly prevalent with substantial impacts on quality of life and health care utilization. The impact of obesity on FI remains unclear, with differing conclusions using body mass index (BMI) as a risk factor. We aimed to determine the association between obesity and FI, and whether this relationship is dependent on the distribution of adiposity (waist circumference-to-height ratio [WHtR]).

METHODS

This was a population-based analysis of the National Health and Nutrition Examination Survey, including participants who responded to the bowel health survey in 2005 to 2010. FI was defined by the accidental bowel leakage of solid stool, liquid, or mucus at least once in the past month. Stepwise multivariable logistic regression models were constructed to assess risk factors for FI.

RESULTS

A total of 7606 participants were included, with an overall FI prevalence of 9.2%. When stratified by quartiles of body measurements, FI was increasingly prevalent from the 1st to the 4th quartile for both WHtR (range, 5.3%-12.5%) and BMI (range, 7.1%-10.5%). WHtR was associated with FI and was a stronger predictor than BMI in all quartiles of body measurement. On multivariable analysis, WHtR remained a significant predictor of FI comparing the 4th with the 1st quartile of body measurements (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.11-2.80; P = .017), whereas BMI was not. A WHtR cutoff of >0.592 optimized the Youden index in prediction of FI in the overall sample.

CONCLUSION

WHtR was independently associated with increased odds of FI in this nationally representative sample of United States adults, whereas BMI was not consistently correlated. This suggests bowel continence may depend more on how body mass is distributed.

Effect of intra-vaginal electric stimulation on bladder compliance in stress urinary incontinence patients: the involvement of autonomic tone

Objective

In addition to the well-established advantage that strengthened pelvic musculature increases urethral resistance in stress urinary incontinence (SUI) patients, intra-vaginal electrical stimulation (iVES) has been shown in preclinical studies to improve bladder capacity via the pudendal-hypogastric mechanism. This study investigated whether iVES also benefits bladder storage in SUI patients by focusing on compliance, a viscoelastic parameter critically defining the bladder's storage function, in a clinical study. Moreover, the potential involvement of stimulation-induced neuromodulation in iVES-modified compliance was investigated by comparing the therapeutic outcomes of SUI patients treated with iVES to those who underwent a trans-obturator tape (TOT) implantation surgery, where a mid-urethral sling was implanted without electric stimulation.

Patients and methods

Urodynamic and viscoelastic data were collected from 21 SUI patients treated with a regimen combining iVES and biofeedback-assisted pelvic floor muscle training (iVES-bPFMT; 20-min iVES and 20-min bPFMT sessions, twice per week, for 3 months). This regimen complied with ethical standards. Data from 21 SUI patients who received TOT implantation were retrospectively analyzed. Mean compliance (Cm), infused volume (Vinf), and threshold pressure (Pthr) from the pressure-flow/volume investigations were assessed.

Results

Compared with the pretreatment control, iVES-bPFMT consistently and significantly increased Cm (18/21; 85%, p = 0.017, N = 21) and Vinf (16/21; 76%, p = 0.046; N = 21) but decreased Pthr (16/21; 76%, p = 0.026, N = 21). In contrast, TOT implantation did not result in consistent or significant changes in Cm, Vinf, or Pthr (p = 0.744, p = 0.295, p = 0.651, respectively; all N = 21).

Conclusion

Our results provide viscoelastic and thermodynamic evidence supporting an additional benefit of iVES-bPFMT to bladder storage in SUI patients by modifying bladder compliance, possibly due to the potentiated hypogastric tone, which did not occur in TOT-treated SUI patients.Clinical trial registration: ClinicalTrials.gov, NCT02185235 and NCT05977231.

Motor dysfunction of the gut in Duchenne muscular dystrophy: A review

BACKGROUND

Duchenne's muscular dystrophy (DMD) is a severe type of hereditary, neuromuscular disorder caused by a mutation in the dystrophin gene resulting in the absence or production of truncated dystrophin protein. Conventionally, clinical descriptions of the disorder focus principally on striated muscle defects; however, DMD manifestations involving gastrointestinal (GI) smooth muscle have been reported, even if not rigorously studied.

PURPOSE

The objective of the present review is to offer a comprehensive perspective on the existing knowledge concerning GI manifestations in DMD, focusing the attention on evidence in DMD patients and mdx mice. This includes an assessment of symptomatology, etiological pathways, and potential corrective approaches. This paper could provide helpful information about DMD gastrointestinal implications that could serve as a valuable orientation for prospective research endeavors in this field. This manuscript emphasizes the effectiveness of mdx mice, a DMD animal model, in unraveling mechanistic insights and exploring the pathological alterations in the GI tract. The gastrointestinal consequences evident in patients with DMD and the mdx mice models are a significant area of focus for researchers. The exploration of this area in depth could facilitate the development of more efficient therapeutic approaches and improve the well-being of individuals impacted by the condition.

Association between dietary inflammatory index and fecal incontinence in American adults: a cross-sectional study from NHANES 2005-2010

Objective

Recent studies have demonstrated that the Dietary Inflammatory Index (DII) is relevant to abnormal gut health. However, there is a lack of studies that have explicitly explored the link between fecal incontinence (FI) and DII. The current study aims to explore the relationship between DII and FI.

Methods

The cross-sectional study enrolled a total of 11,747 participants aged 20-85 from NHANES 2005-2010. Weighted logistic regression was conducted to evaluate the relationship between DII and FI, and restricted cubic spline (RCS) was employed to assess the dose-response relationship between DII and FI. Subgroup analyses were performed according to age, gender, race, and BMI.

Result

DII levels were found to be significantly higher in patients with FI than in the normal population (p = 0.016). After adjusting for all covariates, DII was found to be significantly correlated with FI (model 2: Q4 vs. Q1, OR = 1.49, 95% CI: 1.04-2.14, p = 0.032, p for trend = 0.039). The dose-response curve revealed that there was no non-linear correlation between DII and FI (p-non-linear = 0.234). Subsequent subgroup analyses uncovered that DII was notably associated with FI in the old (Q4 vs. Q1, OR = 1.84, 95% CI: 1.07-3.18, p = 0.030), female (Q4 vs. Q1: OR = 2.02, 95% CI: 1.23-3.33, p = 0.008), non-Hispanic white (Q4 vs. Q1: OR = 1.70, 95% CI: 1.12-2.59, p = 0.015) populations.

Conclusion

DII was positively associated with FI, particularly among old, female and non-Hispanic white individuals. Decreasing daily dietary inflammatory levels may be an effective tactic to prevent FI, but the precise mechanisms need to be further investigated.

Perception of defecation intent: applied methods and technology trends

The aging population has led to a widening gap between the supply and demand for defecation care. To address this issue, the development of defecation care devices is the most direct and effective solution. Pre-defecation care devices offer a more personalized and comfortable alternative to the conventional post-defecation care devices currently available on the market. Furthermore, they facilitate greater patient involvement in the care process. Real-time monitoring and accurate identification of defecation intention are key technologies in the development of pre-defecation nursing devices. Automatic and accurate online monitoring of defecation intention can provide accurate early warning information for differentiated defecation assistance and cleansing care, effectively reducing nursing workload and improving patients' quality of life. However, there are relatively few studies on real-time monitoring and accurate identification of defecation intention. This review summarizes the existing defecation intention sensing technologies and their monitoring principles and research status, and explores the potential development direction of defecation intention sensing systems by comparing the characteristics and application conditions of various sensing technologies, which provides a direction for perception strategies for future defecation intention monitoring and early warning research.

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.

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.

Characterization of obstructive defecation from a structural and a functional perspective

BACKGROUND/AIMS

Defecation disorders can occur as a consequence of functional or structural anorectal dysfunctions during voiding. The aims of this study is to assess the prevalence of structural (SDD) vs functional (FDD) defecation disorders among patients with clinical complaints of obstructive defecation (OD) and their relationship with patients' expulsive capacity.

PATIENTS AND METHODS

Retrospective study of 588 patients with OD studied between 2012 and 2020 with evacuation defecography (ED), and anorectal manometry (ARM) in a subgroup of 294.

RESULTS

90.3% patients were women, age was 58.5±12.4 years. Most (83.7%) had SDD (43.7% rectocele, 45.3% prolapse, 19.3% enterocele, and 8.5% megarectum), all SDD being more prevalent in women except for megarectum. Functional assessments showed: (a) absence of rectification of anorectal angle in 51% of patients and poor pelvic descent in 31.6% at ED and (b) dyssynergic defecation in 89.9%, hypertonic IAS in 44%, and 33.3% rectal hyposensitivity, at ARM. Overall, 46.4% of patients were categorized as pure SDD, 37.3% a combination of SDD+FDD, and 16.3% as having pure FDD. Rectal emptying was impaired in 66.2% of SDD, 71.3% of FDD and in 78% of patients with both (p=0.017).

CONCLUSIONS

There was a high prevalence of SDD in middle-aged women with complaints of OD. Incomplete rectal emptying was more prevalent in FDD than in SDD although FDD and SDD frequently coexist. We recommend a stepwise therapeutic approach always starting with therapy directed to improve FDD and relaxation of striated pelvic floor muscles.

Pleasurable and problematic receptive anal intercourse and diseases of the colon, rectum and anus

The ability to experience pleasurable sexual activity is important for human health. Receptive anal intercourse (RAI) is a common, though frequently stigmatized, pleasurable sexual activity. Little is known about how diseases of the colon, rectum, and anus and their treatments affect RAI. Engaging in RAI with gastrointestinal disease can be difficult due to the unpredictability of symptoms and treatment-related toxic effects. Patients might experience sphincter hypertonicity, gastrointestinal symptom-specific anxiety, altered pelvic blood flow from structural disorders, decreased sensation from cancer-directed therapies or body image issues from stoma creation. These can result in problematic RAI - encompassing anodyspareunia (painful RAI), arousal dysfunction, orgasm dysfunction and decreased sexual desire. Therapeutic strategies for problematic RAI in patients living with gastrointestinal diseases and/or treatment-related dysfunction include pelvic floor muscle strengthening and stretching, psychological interventions, and restorative devices. Providing health-care professionals with a framework to discuss pleasurable RAI and diagnose problematic RAI can help improve patient outcomes. Normalizing RAI, affirming pleasure from RAI and acknowledging that the gastrointestinal system is involved in sexual pleasure, sexual function and sexual health will help transform the scientific paradigm of sexual health to one that is more just and equitable.

Correlation between congenital pelvic floor muscle development assessed by magnetic resonance imaging and postoperative defecation

OBJECTIVE

Children with congenital anorectal malformation (CAM) experience challenges with defecation. This study aims to assess defecation in preschool-age children with CAM and to evaluate the correlation between pelvic floor muscle developed assessed by magnetic resonance imaging (MRI) and postoperative defecation.

METHODS

We collected clinical data and MRI results from 89 male children with CAM. The bowel function scores for children with Perineal (cutaneous) fistula, Rectourethral fistula(Prostatic or Bulbar), and Rectovesical fistula were computed. MRI scans were subjected to image analysis of the striated muscle complex (SMC). The association between pelvic floor muscle score and bowel function score was examined using the Cochran-Armitage Trend Test.

RESULTS

We observed that 77.4% of the SMC scores by MRI for Perineal fistula were good. The Rectourethral fistula SMC score was 40.6% for moderate and 59.4% for poor. The SMC score for Rectovesical fistula was 100% for moderate. Furthermore, 77.4% of patients with Perineal fistula had bowel function scores (BFS) ≥ 17 points. Among those with Rectourethral fistula and Rectovesical fistula, 12.5% and 0 had BFS ≥ 17 points, respectively. An analysis of muscle development and bowel function in patients with Rectovesical fistula, Rectourethral fistula, and Perineal fistula revealed a correlation between SMC development and BFS. Subgroup analysis showed that the Perineal fistula had statistical significance; however, the Rectourethral fistula and Rectovesical fistula were not statistically significant.

CONCLUSION

A correlation exists between pelvic floor muscle development and postoperative defecation in children with Perineal fistula.

The rhizomes of Atractylodes macrocephala relieve loperamide-induced constipation in rats by regulation of tryptophan metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Constipation is one of the most prevalent gastrointestinal tract diseases that seriously affects health-related quality of human life and requires effective treatments without side effect. The rhizome of Atractylodes macrocephala Koidz. (Compositae), called Atractylodes Macrocephala Rhizome (AMR), a commonly used traditional Chinese medicine, has been used to relieve the clinical symptoms of patients with constipation.

AIM OF THE STUDY

To reveal the dose-dependent laxative effect and potential mechanism of AMR on loperamide-induced slow transit constipation (STC) rats.

MATERIALS AND METHODS

Loperamide-induced constipation rat model was established and the dose-dependent laxative effect of AMR was investigated. Untargeted metabolomics based on an UPLC-Q/TOF-MS technique combined with western blot analysis was used to explain the potential mechanism of AMR relieve loperamide-induced constipation in rats.

RESULTS

The results showed that medium dose of AMR (AMR-M, 4.32 g raw herb/kg) and high dose of AMR (AMR-H, 8.64 g raw herb/kg) treatments significantly increased the fecal water content, Bristol score, gastrointestinal transit rate, and recovered the damaged colon tissues of constipated rats, but low dose of AMR (AMR-L, 2.16 g raw herb/kg) did not show laxative effect. Both AMR-M and AMR-H treatments also remarkably reduced the serum levels of vasoactive intestinal peptide (VIP), somatostatin (SS) and dopamine (DA), and increased the levels of motilin (MTL), gastrin (GAS) and 5-hydroxytryptamine (5-HT). Urine metabolomics revealed that constipation development was mainly ascribed to the perturbed tryptophan metabolism, and AMR-M and AMR-H markedly corrected the abnormal levels of five urine tryptophan metabolites, namely 4,6-dihydroxyquinoline, indole, 4,8-dihydroxyquinoline, 5-hydroxytryptamine, and kynurenic acid. Additionally, western blot analysis confirmed that the abnormal expression of rate-limiting enzyme involving in tryptophan metabolism, including tryptophan hydroxylase (TPH), monoamine oxidase (MAO) and indoleamine-2,3-dioxygenase (IDO) in the colon of constipated rats, were mediated by AMR-M and AMR-H.

CONCLUSIONS

The findings provide insight into the mechanisms of STC and AMR could be developed as new therapeutic agent for prevention or healing of constipation.

TMEM16A in smooth muscle cells acts as a pacemaker channel in the internal anal sphincter

Maintenance of fecal continence requires a continuous or basal tone of the internal anal sphincter (IAS). Paradoxically, the basal tone results largely from high-frequency rhythmic contractions of the IAS smooth muscle. However, the cellular and molecular mechanisms that initiate these contractions remain elusive. Here we show that the IAS contains multiple pacemakers. These pacemakers spontaneously generate propagating calcium waves that drive rhythmic contractions and establish the basal tone. These waves are myogenic and act independently of nerve, paracrine or autocrine signals. Using cell-specific gene knockout mice, we further found that TMEM16A Cl- channels in smooth muscle cells (but not in the interstitial cells of Cajal) are indispensable for pacemaking, rhythmic contractions, and basal tone. Our results identify TMEM16A in smooth muscle cells as a critical pacemaker channel that enables the IAS to contract rhythmically and continuously. This study provides cellular and molecular insights into fecal continence.

Unveiling strain-level dynamics in probiotic activity

Divergent gene content among distinct probiotic strains contributes to varied or conflicting clinical efficacies. Zhang et al. unveils a novel bacterial gene signature, particularly the abfA gene cluster, offering a promising avenue for screening probiotics and advancing our understanding of strain-level activities in the context of gastrointestinal health.

Metabolic and Nutritional Issues after Lower Digestive Tract Surgery: The Important Role of the Dietitian in a Multidisciplinary Setting

Many patients undergo small bowel and colon surgery for reasons related to malignancy, inflammatory bowel disease (IBD), mesenteric ischemia, and other benign conditions, including post-operative adhesions, hernias, trauma, volvulus, or diverticula. Some patients arrive in the operating theatre severely malnourished due to an underlying disease, while others develop complications (e.g., anastomotic leaks, abscesses, or strictures) that induce a systemic inflammatory response that can increase their energy and protein requirements. Finally, anatomical and functional changes resulting from surgery can affect either nutritional status due to malabsorption or nutritional support (NS) pathways. The dietitian providing NS to these patients needs to understand the pathophysiology underlying these sequelae and collaborate with other professionals, including surgeons, internists, nurses, and pharmacists. The aim of this review is to provide an overview of the nutritional and metabolic consequences of different types of lower gastrointestinal surgery and the role of the dietitian in providing comprehensive patient care. This article reviews the effects of small bowel resection on macronutrient and micronutrient absorption, the effects of colectomies (e.g., ileocolectomy, low anterior resection, abdominoperineal resection, and proctocolectomy) that require special dietary considerations, nutritional considerations specific to ostomized patients, and clinical practice guidelines for caregivers of patients who have undergone a surgery for local and systemic complications of IBD. Finally, we highlight the valuable contribution of the dietitian in the challenging management of short bowel syndrome and intestinal failure.

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.

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 (β 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.

Normal or diseased? Navigating indeterminate gut behaviour

Introduction Delayed diagnosis of gut disease is a continuing problem, variously attributed to a range of patient, doctor, and health system factors. Gut disease often begins with indeterminate gut behaviours that are hard to classify. Aim This study aimed to investigate delayed diagnosis from the point of view of the patient, or prospective patient. How gut and gut disease was understood, what might prompt them to seek care, and their experiences of seeking care. Methods Using a qualitative design, we interviewed 44 people in New Zealand. Thirty-three had a diagnosis of gut disease, and 11 did not, though some of the patients in this latter group had symptoms. Results Some participants had a smooth trajectory from first noticing gut symptoms to diagnosis. However, a subgroup of 22 participants experienced long periods of troublesome gut behaviours without a diagnosis. For this subgroup of 22 participants, we found people struggled to work out what was normal, thus influencing when they sought health care. Once they sought health care, experiences of that care could be frustrating, and achieving a diagnosis protracted. Some who remained undiagnosed felt abandoned, though had developed strategies to self-manage. Discussion Indeterminate gut behaviours remain complex to deal with and it can difficult for both patients and doctors to assess when a symptom or group of symptoms need further investigation, watchful waiting or the use of other supportive strategies. Effectively communicating with healthcare staff can be a significant problem and there is currently a gap in support for patients in this regard.

Effectiveness of a high fiber diet in improving constipation in patients with defecatory dyssynergy under treatment with anorrectal biofeedback. Exploratory, randomized clinical trial

INTRODUCTION

Fiber is the initial treatment in chronic functional constipation. However, its role in the group of patients with defecatory dyssynergy is not well established. The objective of the study is to evaluate the efficacy and safety of a high fiber diet in patients with defecatory dyssynergy in the treatment with anorectal biofeedback.

PATIENTS AND METHODS

An exploratory, randomized (1:1), double-blind, controlled «add-on» clinical trial was carried out in a reference center in Spain in patients with functional constipation and defecatory dyssynergy according to the ROMEIV criteria.

CONTROL GROUP

treatment with biofeedback and low-fiber diet (15-20g/day). Experimental group: treatment with biofeedback and high fiber diet (25-30g/day). Analyzed: responder (primary endpoint), patient whose defecatory dyssynergy had been corrected (>20% reduction in anal pressure during the defecation maneuver and normal balloon expulsion test); anorectal parameters (anal relaxation, reduced straining); safety (abdominal symptoms: flatulence, pain, borborygmus, bloating).

RESULTS

A total of 44 patients were randomized: 22 per group. The percentage of responders was 75% (15/20; 95%CI: 53 89%) control group and 70% (14/20; 95%CI: 48-85%) experimental group, P=.225. Differences in favor of the control group were only observed in abdominal symptoms: flatulence (P=.028), abdominal distension (P=.041) and digestive comfort (P=.043).

CONCLUSIONS

In patients with defecatory dyssynergy, a high-fiber diet not only does not improve the efficacy of anorectal biofeedback but is associated with a loss of improvement in abdominal symptoms.

Rectal sensitivity and associated factors in patients with different subtypes of functional defecation disorder

OBJECTIVE

To investigate rectal sensitivity and associated factors in patients with different subtypes of functional defecation disorder (FDD).

METHODS

We segregated individuals diagnosed with FDD into two groups based on their defecation patterns: those with dyssynergic defecation and those with inadequate defecatory propulsion. We gathered general information through questionnaires and assessed rectal sensitivity using anorectal manometry. The rectal sensitivity performances of the two groups were compared; the factors related to rectal sensitivity were analyzed to determine the factors associated with rectal sensitivity, and the effect of biofeedback therapy on rectal sensitivity was clarified.

RESULTS

Rectal sensitivity in different subtypes of FDD decreased, and the difference between the two groups was not statistically significant ( P  > 0.05). There were no statistically significant differences in the first constant sensation volume, defecatory desire volume, and maximum tolerable volume between the different subtypes of FDD ( P  > 0.05). Multi-factor binary logistic regression analysis showed that age, constipation symptom score, and diabetes were all independent risk factors for decreased rectal sensitivity ( P  < 0.05). There were no statistically significant differences between the prior- and post-biofeedback therapy in the first constant sensation volume, defecatory desire volume, and maximum tolerable volume ( P  > 0.05).

CONCLUSION

Rectal sensitivity in different subtypes of FDD decreased. Age, constipation symptom score, and diabetes were independent risk factors for decreased rectal sensitivity. Short-term biofeedback therapy did not improve rectal hyposensitivity in patients with FDD.

A pharmacokinetic evaluation of tenapanor for the treatment of irritable bowel syndrome with constipation: an update of the literature

INTRODUCTION

Tenapanor is the latest addition to the second-line pharmacotherapeutic options for the treatment of irritable bowel syndrome with constipation. It is a first-in-class inhibitor of type 3 sodium/hydrogen exchanger (NHE3), characterized by very low oral absorption. Its pharmacological properties are discussed here based on the latest literature.

AREAS COVERED

A general description of tenapanor is provided, highlighting those pharmacokinetic and pharmacodynamic characteristics of the drug which may be of major importance for tolerability and safety. This description is associated with a summary and analysis of currently available toxicological data.

EXPERT OPINION

Plasma concentrations of free tenapanor after oral administration are well below the half maximal inhibitory concentration for NHE3, so that systemic effects of the drug are minimal. Therefore, the action of tenapanor is limited to NHE3 located on the apical membrane of enterocytes. The consequent reduction in intestinal sodium absorption increases the intraluminal content by osmosis, which in turn enhances the propulsive activity of the colon. Diarrhea is the most frequent adverse effect of tenapanor. Increased fecal sodium and water excretion do not appear to expose patients to short- and long-term hydro-electrolyte imbalances.

Colorectal motility patterns and psychiatric traits in functional constipation and constipation-predominant irritable bowel syndrome: A study from China

BACKGROUND

Functional constipation (FC) and constipation-predominant irritable bowel syndrome (IBS-C) represent a spectrum of constipation disorders. However, the majority of previous clinical investigations have focused on Western populations, with limited data originating from China.

AIM

To determine and compare the colorectal motility and psychiatric features of FC and IBS-C in an Eastern Chinese population.

METHODS

Consecutive chronic constipation patients referred to our motility clinic from December 2019 to February 2023 were enrolled. FC and IBS-C diagnoses were established using ROME IV criteria, and patients underwent high-resolution anorectal manometry (ARM) and a colonic transmit test using the Sitz marker study. Constipation-related symptoms were obtained through questionnaires. Anxiety and depression were assessed by the Hamilton anxiety rating scale and the Hamilton Depression Rating Scale-21. The clinical characteristics and colorectal motility patterns of FC and IBS-C patients were compared.

RESULTS

No significant differences in sex, age or abdominal discomfort symptoms were observed between IBS-C and FC patients (all P > 0.05). The proportion of IBS-C patients with delayed colonic transit was higher than that of patients with FC (36.63% vs 15.91%, P < 0.05), while rectosigmoid accumulation of radiopaque markers was more common in the FC group than in the IBS-C group (50% vs 26.73%, P < 0.05). Diverse proportions of these dyssynergic patterns were noted within both the FC and IBS-C groups by ARM. IBS-C patients were found to have a higher prevalence of depression than FC patients (66.30% vs 42.42%, P < 0.05). The scores for feelings of guilt, suicide, psychomotor agitation, diurnal variation, obsessive/compulsive disorder, hopelessness, self-abasedment and gastrointestinal symptoms were significantly higher in IBS-C patients than that in FC patients (P < 0.05). For IBS-C (χ2 = 5.438, P < 0.05) but not FC, patients with normal colon transit time were significantly more likely to have anxiety than those with slow colon transit time. For IBS-C patients but not FC patients, the threshold of first constant sensation, desire to defecate and sustained urgency were all weakly correlated with the degree of anxiety (r = 0.414, r = 0.404, and r = 0.418, respectively, P < 0.05). The proportion of patients with a low threshold of desire to defecate among IBS-C patients with depression was lower than that in those without depression (69.6% vs 41.9%, χ2 = 4.054, P < 0.05).

CONCLUSION

Our findings highlight both overlapping and distinctive patterns of colon transit, dyssynergic patterns, anorectal sensation, psychological distress, and associations of psychiatric and colorectal motility characteristics in FC and IBS-C patients in an Eastern Chinese population, providing valuable insights into the pathophysiological underpinnings of these disorders.

[Functional-neurosurgical treatment options for functional pelvic floor disorders : Value of sacral neuromodulation]

BACKGROUND

Sacral neuromodulation is an established minimally invasive therapy indicated for the treatment of functional pelvic floor disorders. While it received its original US Food and Drug Administration (FDA) approval for the treatment of overactive bladder symptoms, it is now regarded as a therapeutic option to treat both urinary/fecal incontinence and retention. In addition, it has proven to be a valuable tool in the treatment of chronic pelvic pain, and preliminary results indicate a potential to elicit improvements in sexual functioning.

OBJECTIVE

This article serves to provide a summary of the therapy and its applications.

METHOD

Selective literature review.

RESULTS

Sacral neuromodulation implants allow for the controlled shifting of the autonomic control of bladder and rectum towards an inhibition or facilitation of voiding, dependent on the patient's needs and under the patient's control. At the same time and depending on the applied stimulation, the implants can interfere with the nerve's conduction of pain signals. This makes them a therapeutic option for pelvic pain that fails to respond to conventional treatment. Finally, there have been first reports suggesting improvements in sexual dysfunction under sacral neuromodulation, thus, potentially opening up a new line of therapy for those disorders.

DISCUSSION

Sacral neuromodulation is a flexible and efficient form of therapy for functional disorders of the pelvic floor. Specifically, the same intervention can treat seemingly contradictory disorders such as urinary/fecal incontinence and retention as well as chronic pain.

Effectiveness and safety of digital rectal stimulation and abdominal massage for neurogenic bowel dysfunction in stroke patients: a randomized controlled trial protocol

BACKGROUND

Neurogenic bowel dysfunction (NBD) is a prevalent complication among stroke patients, significantly affecting their quality of life, duration of hospitalization, medical expenses, and even mortality. Although current guidelines suggest a conservative strategy for addressing bowel dysfunction, which includes techniques such as digital rectal stimulation (DRS) and abdominal massage, the availability of interventions remains limited in healthcare facilities.

METHODS

This study follows a prospective randomized controlled parallel-group clinical trial design. The control group will receive standard care, while the intervention group will undergo a program that combines DRS and abdominal massage in addition to standard care. The duration of the intervention for both groups will be 6 weeks. The primary outcome measures will be the Wexner score. Furthermore, secondary outcomes measure will be assessed, including Bristol score, Patient Assessment of Constipation-Quality of Life (PAC-QoL), and Fecal Incontinence Quality of Life (FI-QoL).

DISCUSSION

This study aims to evaluate the effectiveness and safety of a bowel rehabilitation program for stroke patients with NBD. The findings will provide information that can contribute to the formulation of bowel management strategies.

TRIAL REGISTRATION

The study has been registered in the Chinese Clinical Registry under the number ChiCTR2300071709. This registration was completed on May 23, 2023. All items from the World Health Organization Trial Registration Data set are described in this manuscript.

Evaluating the risk factors for the development of benign disorders of defaecation: a surgical perspective

PURPOSE

There remains uncertainty as to which risk factors are important for the development of defaecatory problems as a result of heterogeneity of published evidence. Understanding the impact of risk factors may be important in selecting targets for disease prevention or reversal. The aim of this study was to identify and evaluate risk factors for faecal incontinence and chronic constipation.

METHODS

Risk factors for chronic constipation and faecal incontinence were long-listed from scientific literature, then anonymously evaluated (by 50 predominantly colorectal surgical experts from the UK Pelvic Floor Society) using a Delphi technique. Each risk factor was rated as independent, a co-factor, or not a risk factor. Independent risk factors were rated between 1 (not important) and 10 (critically important) with mean (± standard deviation) calculated.

RESULTS

Thirty-eight risk factors for chronic constipation were evaluated. Eighteen were classed as independent and 16 as co-factors. Opioid analgesia (7.87 ± 2.05), eating disorders (7.80 ± 1.72), and history of abuse (7.70 ± 1.89) were scored as most important independent risk factors. Female sex (6.60 ± 2.02) was considered an independent risk factor but increasing age was rated a co-factor. Thirty-three risk factors for faecal incontinence were evaluated. Twenty were classed as independent and eight as co-factors. Third- or fourth-degree tear (8.88 ± 1.57), instrumental delivery (8.47 ± 1.58), and grand multiparity (8.00 ± 1.63) were rated most important. Increasing age (7.41 ± 2.14) and female sex (7.58 ± 2.05) were both considered independent risk factors.

CONCLUSIONS

Several risk factors for chronic constipation and faecal incontinence were selected by Delphi approach. These factors will feed forward into Bayesian models of disease prediction that combine data and expert knowledge.

Slowed Intestinal Transit Induced by Less Mucus in Intestinal Goblet Cell Piezo1-Deficient Mice through Impaired Epithelial Homeostasis

Mucus secreted by goblet cells (GCs) may play an important role in intestinal transit function. Our previous study found that Piezo1 protein is essential for GC function; however, the effect of GC Piezo1 on intestinal transit function is unclear. Our study aimed to investigate the effect of Piezo1 in GCs on intestinal transit and the potential mechanism. We compared intestinal mucus, fecal form, intestinal transit time, intestinal epithelial cell composition, and stem cell function in WT and GC-specific Piezo1-deficient (Piezo1ΔGC) mice. Our results revealed a correlation between mucus and intestinal transit: the less mucus there was, the slower the intestinal transit. Piezo1 deficiency in GCs led to decreased mucus synthesis and also disrupted the ecological niche of colon stem cells (CSCs). Through organoid culture, we found that the capacity of proliferation and differentiation in Piezo1ΔGC mouse CSCs was significantly decreased, which also led to a reduced source of GCs. Further studies found that the reduced Wnt and Notch signals in colon crypts might be the potential mechanism. These results indicated the importance of GC Piezo1 in intestinal transit function, which acts by maintaining the homeostasis of intestinal epithelial cells and mucus.

Piezo1 in Digestive System Function and Dysfunction

Piezo1, a non-selective cation channel directly activated by mechanical forces, is widely expressed in the digestive system and participates in biological functions physiologically and pathologically. In this review, we summarized the latest insights on Piezo1's cellular effect across the entire digestive system, and discussed the role of Piezo1 in various aspects including ingestion and digestion, material metabolism, enteric nervous system, intestinal barrier, and inflammatory response within digestive system. The goal of this comprehensive review is to provide a solid foundation for future research about Piezo1 in digestive system physiologically and pathologically.

DRG afferents that mediate physiologic and pathologic mechanosensation from the distal colon

The properties of dorsal root ganglia (DRG) neurons that innervate the distal colon are poorly defined, hindering our understanding of their roles in normal physiology and gastrointestinal (GI) disease. Here, we report genetically defined subsets of colon-innervating DRG neurons with diverse morphologic and physiologic properties. Four colon-innervating DRG neuron populations are mechanosensitive and exhibit distinct force thresholds to colon distension. The highest threshold population, selectively labeled using Bmpr1b genetic tools, is necessary and sufficient for behavioral responses to high colon distension, which is partly mediated by the mechanosensory ion channel Piezo2. This Aδ-HTMR population mediates behavioral over-reactivity to colon distension caused by inflammation in a model of inflammatory bowel disease. Thus, like cutaneous DRG mechanoreceptor populations, colon-innervating mechanoreceptors exhibit distinct anatomical and physiological properties and tile force threshold space, and genetically defined colon-innervating HTMRs mediate pathophysiological responses to colon distension, revealing a target population for therapeutic intervention.

PIEZO2 in somatosensory neurons controls gastrointestinal transit

The gastrointestinal tract is in a state of constant motion. These movements are tightly regulated by the presence of food and help digestion by mechanically breaking down and propelling gut content. Mechanical sensing in the gut is thought to be essential for regulating motility; however, the identity of the neuronal populations, the molecules involved, and the functional consequences of this sensation are unknown. Here, we show that humans lacking PIEZO2 exhibit impaired bowel sensation and motility. Piezo2 in mouse dorsal root, but not nodose ganglia is required to sense gut content, and this activity slows down food transit rates in the stomach, small intestine, and colon. Indeed, Piezo2 is directly required to detect colon distension in vivo. Our study unveils the mechanosensory mechanisms that regulate the transit of luminal contents throughout the gut, which is a critical process to ensure proper digestion, nutrient absorption, and waste removal.

Inhibited postprandial retrograde cyclic motor pattern in the distal colon of patients with diarrhea-predominant irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) have recurrent lower abdominal pain, associated with altered bowel habit (diarrhea and/or constipation). As bowel habit is altered, abnormalities in colonic motility are likely to contribute; however, characterization of colonic motor patterns in patients with IBS remains poor. Utilizing fiber-optic manometry, we aimed to characterize distal colonic postprandial colon motility in diarrhea-predominant IBS. After an overnight fast, a 72-sensor (spaced at 1-cm intervals) manometry catheter was colonoscopically placed to the proximal colon, in 13 patients with IBS-D and 12 healthy adults. Recordings were taken for 2 h pre and post a 700 kcal meal. Data were analyzed with our two developed automated techniques. In both healthy adults and patients with IBS-D, the dominant frequencies of pressure waves throughout the colon are between 2 and 4 cycles per minute (cpm) and the power of these frequencies increased significantly after a meal. Although these pressure waves formed propagating contractions in both groups, the postprandial propagating contraction increase was significantly smaller in patients compared with healthy adults. In healthy adults during the meal period, retrograde propagation between 2 and 8 cpm was significantly greater than antegrade propagation at the same frequencies. This difference was not observed in IBS-D. Patients with IBS-D show reduced prevalence of the retrograde cyclic motor pattern postprandially compared with the marked prevalence in healthy adults. We hypothesize that this reduction may allow premature rectal filling, leading to postprandial urgency and diarrhea.NEW & NOTEWORTHY Compared with healthy adults this study has shown a significant reduction in the prevalence of the postprandial retrograde cyclic motor pattern in the distal colon of patients with diarrhea-predominant irritable bowel syndrome. We hypothesize that this altered motility may allow for premature rectal filling which contributes to the postprandial urgency and diarrhea experienced by these patients.

Relief from behind: enemas, the back door enforcement to help treating chronic constipation in adults

INTRODUCTION

Chronic constipation is a frequent symptom encountered in the daily clinical practice. The treatment of this condition mainly relies on the use of laxatives. However, patients' satisfaction with this approach is limited, and alternative measures are often added to the treatment. Among these, particularly frequent worldwide is the use of enemas, even though literature data on its scientific validity are scarce.

AREAS COVERED

In this article, by an extensive online search of Medline (through PubMed), Scopus, Cochrane CENTRAL, EMBASE, and the Science Citation Index, the available literature data on the use of enemas in adult patients with chronic constipation, also in the perspective of available guidelines on treatment of this pathological condition, were analyzed.

EXPERT OPINION

Although the use of enemas remains a frequently employed method and it is considered as useful by many physicians as an adjunctive support for the treatment of chronic constipation in adults, this practice is not substantiated by rigorous scientific data, and some studies are available only for specific instances (fecal impaction, transanal irrigation). Thus, waiting for more robust scientific data, enemas treatment should be carried out on an individual patient's basis, according to the experience of the caring physicians.

Complications and Functional Outcome Differences in Carbon Ion Radiotherapy and Surgery for Malignant Bone Tumors of the Pelvis: A Multicenter, Cohort Study

BACKGROUND

Carbon ion radiotherapy (CIRT) is an evolving treatment option for malignant pelvic tumors in patients with poor surgical indications. However, the difference in complications and functional outcomes between CIRT and surgery is poorly understood. This study compares the complications and functional outcomes of CIRT and surgery to facilitate treatment selection.

METHODS

A total of 28 patients who underwent CIRT for pelvic bone tumors while theoretically meeting the surgical resection criteria were included. Sixty-nine patients who underwent surgery for pelvic bone tumors were included as controls. Major complication rates and functional outcomes (ambulatory, pain, urination, constipation) were evaluated and compared at several time points (pretreatment, discharge, and final follow-up) between the groups.

RESULTS

Early (within 90 days) major complications were not observed in the CIRT group but occurred in 30% of the surgery group, which was statistically significant (P < 0.001). In contrast, late (after 90 days) major complications occurred more often in the CIRT group than in the surgery group (18% and 4%, respectively; P = 0.042). From pretreatment until discharge, all functional outcomes in the surgery group deteriorated (P < 0.001 for all) but did not change in the CIRT group (P = 0.77-1.00). At the final follow-up, all functional outcomes showed no significant intergroup difference (P = 0.28-0.92) due to the recovery trend in the surgery group and the deterioration trend in the CIRT group.

CONCLUSIONS

Compared with surgery, CIRT may have favorable safety and stable functional outcomes in the short-term but more late complications. Mid-term functional outcomes were similar between the groups.

Accuracy of Anorectal Manometry to Detect the Rectoanal Inhibitory Reflex in Children: Awake Versus Under General Anesthesia

OBJECTIVES

Our objective was to investigate if there is a difference in the detection of the rectoanal inhibitory reflex (RAIR) when an anorectal manometry (ARM) is performed awake or under general anesthesia.

METHODS

A retrospective review of ARM studies was performed to identify children who had undergone ARMs both while awake and under general anesthesia. We compared ARM outcomes including the detection of the RAIR and anal canal resting pressure.

RESULTS

Thirty-four children had received ARMs both while awake and under general anesthesia (53% female, median age at first ARM 7.5 years [range 3-18 years]). In 9 of 34 (26%) children the RAIR was solely identified during ARM under general anesthesia and not during ARM while awake. In 6 of 9 (66%) this was unrelated to the balloon volumes used during balloon inflations. In 4 of 34 (12%) children, assessment of the RAIR was inconclusive during ARM under general anesthesia due to too low, or loss of anal canal pressure. In 2 of those children, ARMs while awake showed presence of a RAIR. Anal canal resting pressures were higher during ARM while awake versus ARM under general anesthesia (median 70 [interquartile range, IQR 59-85] vs 46 mmHg [IQR 36-65] respectively, P < 0.001).

CONCLUSIONS

General anesthesia may affect the detection of a RAIR in 2 ways. On the one hand, it may facilitate better visualization in children in whom a RAIR could not be visualized while awake. On the other hand, it may cause a loss of anal canal pressure resulting in an inconclusive test result.

Novel Nonablative Radiofrequency Approach for the Treatment of Anal Incontinence: A Phase 1 Clinical Trial

OBJECTIVE

We aimed to describe the action, impact on quality of life, and side effects of perianal nonablative radiofrequency (RF) application in the treatment of anal incontinence (AI) in women.

METHODS

This was a pilot, randomized clinical trial conducted between January and October 2016. We enrolled women who consecutively attended the Attention Center of the Pelvic Floor (CAAP) with complaints of AI for more than six months. Nonablative RF was applied to the perianal region of the participants using Spectra G2 (Tonederm®, Rio Grande do Sul, Brazil). The reduced or complete elimination of the need for protective undergarments (diapers and absorbents) was considered a partial therapeutic response.

RESULTS

Nine participants reported treatment satisfaction, while one reported dissatisfaction with the nonablative RF treatment of AI based on the Likert scale. No patient interrupted treatment sessions because of adverse effects, although adverse effects occurred in six participants. However, the clinical and physical examination of the participants with burning sensations showed no hyperemia or mucosal lesions.

CONCLUSIONS

This study showed a promising reduction of fecal loss, participant satisfaction with treatment, and improved lifestyle, behavior, and depression symptoms with minimal adverse effects.

Proinflammatory Diet Is Associated With Increased Risk of Fecal Incontinence Among Older Women: Prospective Results From the Nurses' Health Study

Fecal incontinence (FI) is a debilitating gastrointestinal disorder with a devastating impact on quality of life,1,2 particularly on older women, partly because of unique risk factors including parity and menopause.2,3 Therefore, identifying modifiable factors, such as diet, are crucial for developing effective prevention strategies for FI among those at risk. We previously found higher dietary fiber intake was associated with lower FI risk,4 providing the first population-based data to connect diet and FI prevention. However, prospective evidence on other dietary factors and FI risk has been limited. Dietary patterns may be associated with gut microbiome characteristics, which may influence inflammatory responses in the gastrointestinal tract5 and drive neurosensory disturbances.6 Moreover, chronic inflammation may drive reduced muscle mass and function,7 and pelvic floor dysfunction is an established FI risk factor.1,2 We hypothesized that a proinflammatory dietary pattern may be associated with increased FI risk and tested this hypothesis in the Nurses' Health Study.

Post-Operative Anorectal Manometry in Children following Anorectal Malformation Repair: A Systematic Review

Despite surgical correction, children with anorectal malformations may experience long-term bowel dysfunction, including fecal incontinence and/or disorders of evacuation. Anorectal manometry is the most widely used test of anorectal function. Although considerable attention has been devoted to its application in the anorectal malformation cohort, there have been few attempts to consolidate the findings obtained. This systematic review aimed to (1) synthesize and evaluate the existing data regarding anorectal manometry results in children following anorectal malformation repair, and (2) evaluate the manometry protocols utilized, including equipment, assessment approach, and interpretation. We reviewed four databases (Embase, MEDLINE, the Cochrane Library, and PubMed) for relevant articles published between 1 January 1985 and 10 March 2022. Studies reporting post-operative anorectal manometry in children (<18 years) following anorectal malformation repair were evaluated for eligibility. Sixty-three studies were eligible for inclusion. Of the combined total cohort of 2155 patients, anorectal manometry results were reported for 1755 children following repair of anorectal malformations. Reduced resting pressure was consistently identified in children with anorectal malformations, particularly in those with more complex malformation types and/or fecal incontinence. Significant variability was identified in relation to manometry equipment, protocols, and interpretation. Few studies provided adequate cohort medical characteristics to facilitate interpretation of anorectal manometry findings within the context of the broader continence mechanism. This review highlights a widespread lack of standardization in the anorectal manometry procedure used to assess anorectal function in children following anorectal malformation repair. Consequently, interpretation and comparison of findings, both within and between institutions, is exceedingly challenging, if not impossible. Standardized manometry protocols, accompanied by a consistent approach to analysis, including definitions of normality and abnormality, are essential to enhance the comparability and clinical relevance of results.

Altered Gut Microbic Flora and Haemorrhoids: Could They Have a Possible Relationship?

To date, the exact pathophysiology of haemorrhoids is poorly understood. The different philosophies on haemorrhoids aetiology may lead to different approaches of treatment. A pathogenic theory involving a correlation between altered anal canal microflora, local inflammation, and muscular dyssynergia is proposed through an extensive review of the literature. Since the middle of the twentieth century, three main theories exist: (1) the varicose vein theory, (2) the vascular hyperplasia theory, and (3) the concept of a sliding anal lining. These phenomena determine changes in the connective tissue (linked to inflammation), including loss of organization, muscular hypertrophy, fragmentation of the anal subepithelial muscle and the elastin component, and vascular changes, including abnormal venous dilatation and vascular thrombosis. Recent studies have reported a possible involvement of gut microbiota in gut motility alteration. Furthermore, dysbiosis seems to represent the leading cause of bowel mucosa inflammation in any intestinal district. The alteration of the gut microbioma in the anorectal district could be responsible for haemorrhoids and other anorectal disorders. A deeper knowledge of the gut microbiota in anorectal disorders lays the basis for unveiling the roles of these various gut microbiota components in anorectal disorder pathogenesis and being conductive to instructing future therapeutics. The therapeutic strategy of antibiotics, prebiotics, probiotics, and fecal microbiota transplantation will benefit the effective application of precision microbiome manipulation in anorectal disorders.

Diverticular disease, diverticulitis and the impact on continence

Diverticulosis and the subsequent progression to diverticular disease and diverticulitis is becoming more prevalent in western countries. The cause for this progression is not known. Diverticulitis is a significant health burden - both financially to healthcare systems, and to the patients it affects in terms of morbidity. There is a dearth of research pertaining to diverticulitis and its impact on continence. This article examines the parallels between irritable bowel syndrome and diverticular disease, which have many symptom similarities, the overlap between the conditions, and the impact on continence. Current studies regarding the role of fibre in managing diverticular disease are also discussed.

Parachute-like pull-through anastomosis for low rectal cancer: a new method for preservation of anal function

BACKGROUND

With recent improvements in surgical technique, oncological outcomes of low rectal cancer have improved over time. But the QoL impairment as a result of anal functional disorder cannot be ignored. And the incidence of anastomosis-related complications cannot be ignored. To address these problems, a personal technique for pull-through coloanal anastomosis (parachute-like intussuscept pull-through anastomosis) was introduced and evaluated. This technique can relatively reduce surgical complications, minimize the impact of anal function, and obviate a colostomy creation.

METHODS

Between June 2020 and April 2021, 14 consecutive patients with rectal cancer underwent laparoscopic-assisted resection of rectal cancer in our hospital. Parachute-like pull-through anastomosis method was performed in all patients. Anal function, perioperative details, and postoperative outcomes were analyzed.

RESULTS

The mean (SD) operative time of first stage was 282.1 min (range 220-370) with an average estimated blood loss of 90.3 mL (range 33-200). And the mean (SD) operative time of second was 46 min (range 25-76) with an average estimated blood loss of 16.1 mL (range 5-50). Wexner scores declined significantly during the median follow-up of 18 months. Four postoperative anastomosis-related complications occurred in 14 patients, including perianastomotic abscess: 1 case (7%), anastomotic stricture: 1 case (7%), and colonic ischemia of the exteriorized colonic segment: 2 cases (14%).

CONCLUSION

The results suggest that the method can facilitate safe and easy completion of coloanal anastomosis, using parachute-like pull-through anastomosis, with acceptable anal function.

Flow simulations of rectal evacuation: towards a quantitative evaluation from video defaecography

Mechanistic understanding of anorectal (patho)physiology is missing to improve the medical care of patients suffering from defaecation disorders. Our objective is to show that complex fluid dynamics modelling of video defaecography may open new perspectives in the diagnosis of defaecation disorders. Based on standard X-ray video defaecographies, we developed a bi-dimensional patient-specific simulation of the expulsion of soft materials, the faeces, by the rectum. The model quantified velocity, pressure and stress fields during the defaecation of a neostool with soft stool-like rheology for patients showing normal and pathological defaecatory function. In normal defaecation, the proximal-distal pressure gradient resulted from both the anorectal junction which formed a converging channel and the anal canal. The flow of the neostool through these anatomical parts was dominated by its shear-thinning viscous properties, rather than its yield stress. Consequently, the evacuation flow rate was significantly affected by variations in pressure applied by the rectum, and much less by the geometry of the anorectal junction. Lastly, we simulated impaired defaecations in the absence of obvious obstructive phenomena. Comparison with normal defaecation allowed us to discuss critical elements which should lead to effective medical management.

Post-operative colonic manometry in children with anorectal malformations: A systematic review

BACKGROUND

Children with anorectal malformations may experience constipation and fecal incontinence following repair. The contribution of altered anorectal function to these persistent symptoms is relatively intuitive; however, colonic motility in this cohort is less well understood. Manometry may be used to directly assess colonic motility.

PURPOSE

The purpose of this systematic review was to synthesize the available evidence regarding post-operative colonic motility in children with anorectal malformations and evaluate the reported equipment and protocols used to perform colonic manometry in this cohort. This systematic review was conducted in compliance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We conducted a systematic review of four databases: Embase, MEDLINE, PubMed, and the Cochrane Library (1^st January 1985-22^nd July 2021). Studies reporting colonic manometry performed in children following anorectal malformation repair were assessed for eligibility. Data were extracted independently by two authors. Four studies were eligible for inclusion. Of the combined total cohort of 151 children, post-operative colonic manometry was conducted in 35. Insufficient reporting of medical characteristics, bowel function, and manometric outcomes restricted comparison between studies, and limited clinical applicability. No results from high-resolution colonic manometry were identified. Despite the prevalence of post-operative bowel dysfunction in children with repaired anorectal malformations, this systematic review highlighted the markedly limited evidence regarding post-operative colonic motility. This cohort may benefit from assessment with high-resolution techniques; however, future work must emphasize adherence to standardized manometry protocols, and include robust reporting of surgical characteristics, bowel function, and manometric outcomes.

Comparison of Anorectal Manometry, Rectal Balloon Expulsion Test, and Defecography for Diagnosing Defecatory Disorders

BACKGROUND & AIMS

The utility of high-resolution anorectal manometry (HR-ARM) for diagnosing defecatory disorders (DDs) is unclear because healthy people may have features of dyssynergia. We aimed to identify objective diagnostic criteria for DD and to ascertain the utility of HR-ARM for diagnosing DD.

METHODS

Constipated patients were assessed with HR-ARM and rectal balloon expulsion time (BET), and a subset underwent defecography. Normal values were established by assessing 184 sex-matched healthy individuals. Logistic regression models evaluated the association of abnormal HR-ARM findings with prolonged BET and reduced rectal evacuation (determined by defecography).

RESULTS

A total of 474 constipated individuals (420 women) underwent HR-ARM and BET, and 158 underwent defecography. BET was prolonged, suggesting a DD, for 152 patients (32%). Rectal evacuation was lower for patients with prolonged vs normal BET. A lower rectoanal gradient during evacuation, reduced anal squeeze increment, and reduced rectal sensation were independently associated with abnormal BETs; the rectoanal gradient was 36% sensitive and 85% specific for prolonged BET. A lower rectoanal gradient and prolonged BET were independently associated with reduced evacuation. Among constipated patients, the probability of reduced rectal evacuation was 14% when the gradient and BET were both normal, 45% when either was abnormal, and 75% when both variables were abnormal.

CONCLUSIONS

HR-ARM, BET, and defecography findings were concordant for constipated patients, and reduced rectoanal gradient was the best HR-ARM predictor of prolonged BET or reduced rectal evacuation. Prolonged BET, reduced gradient, and reduced evacuation each independently supported a diagnosis of DD in constipated patients. We propose the terms probable DD for patients with an isolated abnormal gradient or BET and definite DD for patients with abnormal results from both tests.

Characterisation of parasympathetic ascending nerves in human colon

Background

In the human large bowel, sacral parasympathetic nerves arise from S2 to S4, project to the pelvic plexus ("hypogastric plexus") and have post-ganglionic axons entering the large bowel near the rectosigmoid junction. They then run long distances orally or aborally within the bowel wall forming "ascending nerves" or "shunt fascicles" running in the plane of the myenteric plexus. They form bundles of nerve fibres that can be distinguished from the myenteric plexus by their straight orientation, tendency not to merge with myenteric ganglia and greater width.

Aim

To identify reliable marker(s) to distinguish these bundles of ascending nerves from other extrinsic and intrinsic nerves in human colon.

Methods

Human colonic segments were obtained with informed consent, from adult patients undergoing elective surgery (n = 21). Multi-layer immunohistochemical labelling with neurofilament-H (NF200), myelin basic protein (MBP), von Willebrand factor (vWF), and glucose transporter 1 (GLUT1), and rapid anterograde tracing with biotinamide, were used to compare ascending nerves and lumbar colonic nerves.

Results

The rectosigmoid and rectal specimens had 6-11 ascending nerves spaced around their circumference. Distal colon specimens typically had 1-3 ascending nerves, with one located near the mesenteric taenia coli. No ascending nerves were observed in ascending colon specimens. GLUT1 antisera labelled both sympathetic lumbar colonic nerves and ascending nerves in the gut wall. Lumbar colonic nerves joined the myenteric plexus and quickly lost GLUT1 labelling, whereas GLUT1 staining labelled parasympathetic ascending nerves over many centimetres.

Conclusion

Ascending nerves can be distinguished in the colorectum of humans using GLUT1 labelling combined with NF200.

Current and future perspectives on the utility of provocative tests of anal sphincter function: A state-of-the-art summary

BACKGROUND

The maintenance of fecal continence depends upon coordinated interactions between the pelvic floor, anorectum, and anal sphincter complex orchestrated by central and peripheral neural activities. The current techniques to objectively measure anorectal function rely on fixed diameter catheters placed inside the anal canal with a rectal balloon to obtain measurements of anal resting and squeeze function, and rectal compliance. Until recently it had not been possible to measure the distensibility of the anal canal, or in other words its ability to resist opening against an increasing pressure, which has been proposed as the main determinant of a biological sphincter's function. Anal acoustic reflectometry (AAR) and the functional lumen imaging probe (FLIP) are two novel, provocative techniques that dynamically assess the anal sphincter complex under volume-controlled distension. In doing so, both provide information on the viscoelastic properties of the anal canal and offer new insights into its function.

PURPOSE

This review details the current and potential future applications of AAR and FLIP and highlights the unanswered questions relevant to these new technologies.

A nurse-led educational intervention for relieving idiopathic constipation: a retrospective study

BACKGROUND

Constipation is a common condition. Although numerous articles emphasise the importance of conservative interventions, none have set out a complete educational programme.

AIMS

To describe the results of an evidence-based, nurse-led educational intervention for functional constipation in adults.

METHODS

A retrospective study of patient records with an analysis of Wexner constipation scores and Bristol stool charts was carried out before and after a nurse-led educational programme on nutrition and bowel habits.

FINDINGS

Twenty-nine patients were enrolled (19 women and 10 men), with a median age of 61 (53-71) years, a mean BMI of 24.4±3.88 kg/m² and comparable baseline Wexner and Bristol scores. A statistically significant improvement in Wexner scores (P<0.001) and a clinically relevant but not statistically significant (P=0.682) improvement in Bristol scores were observed.

CONCLUSION

The results suggest this investigation should be repeated on a larger scale. An educational intervention could be included in all consultations on any issue that could affect bowel activity.