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.

Influence of the examination position and distension medium on the rectal sensory test in patients with functional constipation.

PURPOSE: To evaluate the impact of two different parameters (body position and distension medium) on the rectal sensory test in patients with functional constipation and provide data support for the development of standardized operating procedures in clinical practice. METHODS: Based on a single-center process of the rectal sensory test, 39 patients with functional constipation were recruited for rectal sensory test under different body positions and distension mediums. RESULTS: Among the items of the Constipation Scoring System, the score of frequency of bowel movements showed a negative correlation with the first constant sensation volume (r = -0.323, P = 0.045). Conversely, the score of painful evacuation effort showed a positive correlation with the desire to defecate volume (r = 0.343, P = 0.033). There was a statistically significant difference in the first constant sensation volume (when the distension medium was gas) measured in different body positions (left lateral position, sitting position, squatting position), and the data measured in the squatting position were significantly higher than those in left lateral position (P < 0.05). In terms of research on distension medium, it was found that the first constant sensation volume measured in the squatting position (when the distension medium was water) was significantly lower than that of gas (P < 0.05). CONCLUSION: For patients with functional constipation, there are differences in the results of rectal sensory tests between body positions and distension mediums. When conducting multicenter studies, it is necessary to unify the standard operating procedure (SOP) for operational details to ensure consistency and reliability of the test results.

Efficacy of electroacupuncture therapy in patients with functional anorectal pain: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Some Chinese scholars have initially explored the efficacy of electroacupuncture at Baliao acupoint in patients with functional anorectal pain (FAP). However, their studies are performed in a single center, or the sample size is small. Therefore, we aim to further explore the efficacy of electroacupuncture at Baliao acupoint on the treatment of FAP. METHODS: In this multicenter randomized controlled trial, 136 eligible FAP patients will be randomly allocated into an electroacupuncture group or sham electroacupuncture group at a 1:1 ratio. This trial will last for 34 weeks, with 2 weeks of baseline, 4 weeks and 8 weeks of treatment, and 1, 3, and 6 months of follow-up. Outcome assessors and statisticians will be blind. The primary outcome will be clinical treatment efficacy, and secondary outcomes will be pain days per month, quality of life, psychological state assessment, anorectal manometry, pelvic floor electromyography, and patient satisfaction. DISCUSSION: Results of this trial will be contributed to further clarify the value of electroacupuncture at Baliao acupoint as a treatment for FAP in the clinic. TRIAL REGISTRATION: This trial has been registered in Chinese Clinical Trial Registry  https://www.chictr.org.cn/  (ChiCTR2300069757) on March 24, 2023.

Quality of life and functional outcomes after laparoscopic total mesorectal excision (LaTME) and transanal total mesorectal excision (taTME) for rectal cancer. an updated meta-analysis.

PURPOSE: Concerns exist regarding the potential for transanal total mesorectal excision (TaTME) to yield poorer functional outcomes compared to laparoscopic TME (LaTME). The aim of this study is to assess the functional outcomes following taTME and LaTME, focusing on bowel, anorectal, and urogenital disorders and their impact on the patient's QoL. METHODS: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and A Measurement Tool to Assess systematic Reviews (AMSTAR) guidelines. A comprehensive search was conducted in Medline, Embase, Scopus, and Cochrane Library databases. The variables considered are: Low Anterior Resection Syndrome (LARS), International Prostate Symptom Score (IPSS) and Jorge-Wexner scales; European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C29 and QLQ-C30 scales. RESULTS: Eleven studies involving 1020 patients (497-taTME group/ 523-LaTME group) were included. There was no significant difference between the treatments in terms of anorectal function: LARS (MD: 2.81, 95% CI: - 2.45-8.08, p = 0.3; I2 = 97%); Jorge-Wexner scale (MD: -1.3, 95% CI: -3.22-0.62, p = 0.19). EORTC QLQ C30/29 scores were similar between the groups. No significant differences were reported in terms of urogenital function: IPSS (MD: 0.0, 95% CI: - 1.49-1.49, p = 0.99; I2 = 72%). CONCLUSIONS: This review supports previous findings indicating that functional outcomes and QoL are similar for rectal cancer patients who underwent taTME or LaTME. Further research is needed to confirm these findings and understand the long-term impact of the functional sequelae of these surgical approaches.

Assessing anorectal function in patients with recurrent ulcerative colitis.

PURPOSE: Ulcerative colitis (UC) is an inflammatory bowel disease with an unclear etiology that can lead to irreversible changes in distal colonic function in chronic patients. This study investigated anorectal function in recurrent UC patients and identified influencing factors. METHODS: This prospective study enrolled 33 recurrent UC patients and 40 newly diagnosed patients from January 2019 to December 2022. Data collection included clinical records, scores, and anorectal function assessments. Regression analyses were used to identify factors impacting anorectal function. RESULTS: Recurrent UC patients had higher baseline CRP and fecal calprotectin levels, increased anxiety and depression, and more severe fecal incontinence. They also had lower BMIs, serum Hb and albumin (ALB) levels, and Inflammatory Bowel Disease Questionnaire scores than did initial-onset UC patients. Multivariate linear regression analysis revealed that long disease duration (coef. - 0.376, P < 0.001) and high fecal calprotectin level (coef. - 0.656, P < 0.001) independently influenced the initial sensation threshold in recurrent UC patients. Additionally, high fecal calprotectin (coef. - 0.073, P = 0.013) and high Zung Self-Rating Anxiety Scale score (coef. - 0.489, P = 0.001) were identified as two independent determinants of the defecation volume threshold. For the defecation urgency threshold, the independent factors included high disease duration (coef. - 0.358, P = 0.017) and high fecal calprotectin level (coef. - 0.499, P = 0.001). Similarly, the sole independent factor identified for the maximum capacity threshold was high fecal calprotectin (coef. - 0.691, P = 0.001). CONCLUSION: Recurrent UC patients had increased rectal sensitivity and compromised anorectal function, which significantly impacted quality of life. Proactively managing the disease, reducing UC relapses, and addressing anxiety are effective measures for improving anorectal function in these patients.

Evaluation of anorectal function using real-time tissue elastography before and after preoperative chemoradiotherapy.

PURPOSE: This study aimed to clarify the relationship between changes in elasticity and anorectal function before and after chemoradiotherapy. METHODS: This is a single-center prospective cohort study (Department of Surgical Oncology, The University of Tokyo). We established a technique to quantify internal anal sphincter hardness as elasticity using transanal ultrasonography with real-time tissue elastography. Twenty-seven patients with post-chemoradiotherapy rectal cancer during 2019-2022 were included. Real-time tissue elastography with transanal ultrasonography was performed before and after chemoradiotherapy to measure internal anal sphincter hardness as "elasticity" (hardest (0) to softest (255); decreased elasticity indicated sclerotic changes). The relationship between the increase or decrease in elasticity pre- and post-chemoradiotherapy and the maximum resting pressure, maximum squeeze pressure, and Wexner score were the outcome measures. RESULTS: A decrease in elasticity was observed in 16/27 (59.3%) patients after chemoradiotherapy. Patients with and without elasticity decrease after chemoradiotherapy comprised the internal anal sphincter sclerosis and non-sclerosis groups, respectively. The maximum resting pressure post-chemoradiotherapy was significantly high in the internal anal sphincter sclerosis group (63.0 mmHg vs. 47.0 mmHg), and a majority had a worsening Wexner score (60.0% vs. 18.2%) compared with that of the non-sclerosis group. Decreasing elasticity (internal anal sphincter sclerosis) correlated with a higher maximum resting pressure (r = 0.36); no correlation was observed between the degree of elasticity change and maximum squeeze pressure. CONCLUSION: Internal anal sphincter sclerosis due to chemoradiotherapy may correlate to anorectal dysfunction.

Constipated patients with functional defecatory disorder have secondary rectal hyposensitivity due to altered rectal biomechanics.

BACKGROUND AND AIM: Rectal hyposensitivity (RH) is common in constipation and often coexists with functional defecatory disorder (FDD). Rectal sensory thresholds are routinely evaluated with the anorectal manometry probe; however, the gold standard for the assessment of rectal sensitivity is with a barostat, use of which is limited by time constraints and availability. A novel rapid barostat bag (RBB) may facilitate measurements of rectal sensitivity. The aim is to evaluate the relationship between RH (measured by the RBB) and FDD (defined as any minor disorder of rectoanal coordination by the London classification) in constipated patients. METHODS: Consecutive constipated patients referred for anorectal function testing underwent anorectal manometry with the 3D-HDAM probe as well as rectal sensation testing with the RBB pump. RH was defined by volume to first sensation >30%, urge to defecate >80%, or discomfort >100% (normalized to rectal capacity). RESULTS: Fifty-three percent of constipated patients had RH. Patients with FDD had a significantly increased volume to first sensation (134.5 mL vs 102.0, P = 0.02), urge to defecate (187.0 mL vs 149.0, P = 0.04), and rectal capacity (253.5 mL vs 209.0, P = 0.04) compared to constipated patients without FDD. There was no difference in normalized sensory thresholds (percent of rectal capacity) nor the prevalence of hyposensitivity to each sensory threshold nor overall hyposensitivity. CONCLUSION: Patients with FDD, when measured with the RBB, have increased sensory thresholds on volumetric distension, but RH was not observed when sensory threshold volume were normalized to rectal capacity. This may reflect "secondary" RH due to altered rectal biomechanics.

Relation between the internal anal sphincter and defecation disorders in patients with anorectal malformations.

OBJECTIVES: To investigate associations between the rectoanal inhibitory reflex (RAIR), type of congenital anorectal malformations (ARMs), type of operation that patients with ARM had undergone, and objectively measured fecal incontinence and defecation problems. METHODS: We retrospectively included 69 pediatric patients with ARM. All underwent anorectal function tests at the University Medical Center of Groningen during the last 10 years. We assessed anorectal physiology using the Rome IV criteria and anorectal function tests. RESULTS: We found the reflex in 67% of patients and all types of ARMs. All patients who had not been operated on, and those who had undergone less extensive surgery possessed the reflex. In contrast, patients who underwent posterior sagittal anorectoplasty, 44% possessed it. We found no difference between mean rectal volumes in patients with and without the reflex (251 vs. 325 mL, respectively, p = 0.266). We found that over time, patients without the reflex seemed to develop significantly higher rectal volumes than patients who had it. We did not find a significant difference between the reflex and fecal incontinence; however, it seems that the absence of the reflex, resting anal sphincter pressure, and fecal incontinence are related. CONCLUSION: The RAIR seems present in patients with ARM irrespective of their malformation type. Corrective surgery, however, may impair this reflex. Seemingly, its absence results in constipation with enlarged rectal volumes and fecal incontinence. Every effort should be made to preserve this reflex during surgery and to use extensive surgical procedures as sparingly as possible.

Obesity and Roux-en-Y gastric bypass drive changes in miR-31 and miR-215 expression in the human rectal mucosa.

BACKGROUND/OBJECTIVES: Obesity increases colorectal cancer (CRC) risk. However, the effects of weight loss on CRC risk are unclear. Epigenetic mechanisms involving microRNAs that lead to dysregulated gene expression may mediate the effects of obesity and weight loss on CRC risk. We examined the effects of obesity and weight loss following Roux-en-Y gastric bypass (RYGB) on microRNA expression in the human rectal mucosa. SUBJECTS/METHODS: We collected rectal mucosal biopsies from obese patients (n = 22) listed for RYGB and age- and sex-matched healthy non-obese Controls (n = 20), at baseline and six months post-surgery. We quantified microRNA expression in rectal mucosal biopsies using Next Generation Sequencing and bioinformatics analysis to investigate the likely functional consequences of these epigenetic changes. RESULTS: Compared with non-obese individuals, obese individuals showed differential expression of 112 microRNAs (p < 0.05). At six-months post-RYGB, when mean body mass had fallen by 27 kg, 60 microRNAs were differentially expressed, compared with baseline (p < 0.05). The expression of 36 microRNAs differed significantly between both i) obese and non-obese individuals and ii) obese individuals pre- and post-RYGB. Quantitative polymerase chain reaction (qPCR) demonstrated that expression of miR-31 and miR-215 was significantly (p < 0.05) higher, 143-fold and 15-fold respectively, in obese than in non-obese individuals. Weight loss, following RYGB, reduced expression of miR-31 and miR-215 to levels comparable with Controls. These differentially expressed microRNAs are implicated in pathways linked with inflammation, obesity and cancer. CONCLUSION: Our findings show, for the first time, that obesity is associated with dysregulated microRNA expression in the human rectal mucosa. Further, surgically-induced weight loss may normalise microRNA expression in this tissue.

Translumbosacral Anorectal Magnetic Stimulation Test for Fecal Incontinence.

BACKGROUND: Neuropathy may cause fecal incontinence and mixed fecal incontinence/constipation, but its prevalence is unclear, partly due to the lack of comprehensive testing of spino-anorectal innervation. OBJECTIVE: This study aimed to develop and determine the clinical usefulness of a novel test, translumbosacral anorectal magnetic stimulation for fecal incontinence. DESIGN: This observational cohort study was conducted from 2012 to 2018. SETTINGS: This study was performed at a tertiary referral center. PATIENTS: Patients with fecal incontinence, patients with mixed fecal incontinence/constipation, and healthy controls were included. INTERVENTIONS: A translumbosacral anorectal magnetic stimulation test was performed by using an anorectal probe with 4 ring electrodes and magnetic coil, and by stimulating bilateral lumbar and sacral plexuses, uses and recording 8 motor-evoked potentials at anal and rectal sites. MAIN OUTCOME MEASURES: The prevalence of lumbar and/or sacral neuropathy was examined. Secondary outcomes were correlation of neuropathy with anorectal sensorimotor function(s) and morphological changes. RESULTS: We evaluated 220 patients: 144 with fecal incontinence, 76 with mixed fecal incontinence/constipation, and 31 healthy controls. All 8 lumbar and sacral motor-evoked potential latencies were significantly prolonged (p < 0.01) in fecal incontinence and mixed fecal incontinence/constipation groups compared with controls. Neuropathy was patchy and involved 4.0 (3.0) (median (interquartile range)) sites. Lumbar neuropathy was seen in 29% to 65% of the patients in the fecal incontinence group and 22% to 61% of the patients in the mixed fecal incontinence/constipation group, and sacral neuropathy was seen in 24% to 64% and 29% to 61% of these patients. Anal neuropathy was significantly more (p < 0.001) prevalent than rectal neuropathy in both groups. There was no correlation between motor-evoked potential latencies and anal sphincter pressures, rectal sensation, or anal sphincter defects. LIMITATIONS: No comparative analysis with electromyography was performed. CONCLUSION: Lumbar or sacral plexus neuropathy was detected in 40% to 75% of patients with fecal incontinence with a 2-fold greater prevalence at the anal region than the rectum. Lumbosacral neuropathy appears to be an independent mechanism in the pathogenesis of fecal incontinence, unassociated with other sensorimotor dysfunctions. Translumbosacral anorectal magnetic stimulation has a high yield and is a safe and clinically useful neurophysiological test. See Video Abstract at http://links.lww.com/DCR/B728. PRUEBA DE ESTIMULACIN MAGNTICA TRANSLUMBOSACRAL ANORECTAL PARA LA INCONTINENCIA FECAL: ANTECEDENTES:La neuropatía puede causar incontinencia fecal y una combinación de incontinencia fe-cal/estreñimiento, pero su prevalencia no está clara, en parte debido a la falta de pruebas comple-tas de inervación espino-anorrectal.OBJETIVO:Desarrollar y determinar la utilidad clínica de una nueva prueba, estimulación magnética trans-lumbosacral anorrectal para la incontinencia fecal.DISEÑO:Estudio de cohorte observacional del 2012 al 2018.ENTORNO CLINICO:Centro de referencia terciario.PACIENTES:Pacientes con incontinencia fecal, combinación de incontinencia fecal/estreñimiento y controles sanos.INTERVENCIONES:Se realizó una prueba de estimulación magnética translumbosacral anorrectal utilizando una sonda anorrectal con 4 electrodos anulares y bobina magnética, y estimulando los plexos lumbares y sacros bilaterales y registrando ocho potenciales evocados motores las regiones anal y rectal.PRINCIPALES MEDIDAS DE RESULTADO:Se examinó la prevalencia de neuropatía lumbar y/o sacra. Los resultados secundarios fueron la correlación de la neuropatía con las funciones sensitivomotoras anorrectales y cambios morfológi-cos.RESULTADOS:Evaluamos 220 pacientes, 144 con incontinencia fecal, 76 con combinación de incontinencia fe-cal/estreñimiento y 31 sujetos sanos. Las ocho latencias de los potenciales evocadas motoras lum-bares y sacras se prolongaron significativamente (p <0,01) en la incontinencia fecal y el grupo mixto en comparación con los controles. La neuropatía fue irregular y afectaba 4,0 (3,0) (mediana (rango intercuartílico) sitios. Se observó neuropatía lumbar en 29-65% en la incontinencia fecal y 22-61% en el grupo mixto, y neuropatía sacra en 24-64% y 29-61 % de pacientes respectivamen-te. La neuropatía anal fue significativamente más prevalente (p <0,001) que la rectal en ambos grupos. No hubo correlación entre las latencias de los potenciales evocadas motoras y las presio-nes del esfínter anal, la sensación rectal o los defectos del esfínter anal.LIMITACIONES:Sin análisis comparativo con electromiografía.CONCLUSIÓNES:Se detectó neuropatía del plexo lumbar o sacro en el 40-75% de los pacientes con incontinencia fecal con una prevalencia dos veces mayor en la región anal que en el recto. La neuropatía lumbo-sacra parece ser un mecanismo independiente en la patogenia de la incontinencia fecal, no asocia-do con otras disfunciones sensitivomotoras. La estimulación magnética translumbosacral anorrec-tal tiene un alto rendimiento, es una prueba neurofisiológica segura y clínicamente útil. Consulte Video Resumen en http://links.lww.com/DCR/B728.

Mucosal Integrity Testing Can Detect Differences in the Rectums of Patients with Inflammatory Bowel Disease Compared to Controls: A Pilot Study.

BACKGROUND: While the pathogenesis of inflammatory bowel disease (IBD) is incompletely understood, disruption of epithelial integrity is suspected to play a prominent role in disease initiation and progression. Currently, there is no convenient way to measure this in vivo. AIMS: Our aim is to determine whether a mucosal integrity (MI) testing device that has been used to measure MI in the esophagus can also be used to measure barrier function in the colon during colonoscopy. METHODS: Mucosal integrity testing was measured in patients with IBD (n = 17) and controls (n = 7) during colonoscopy. During the procedure, an MI catheter was passed down the working channel of the colonoscope and placed along the mucosal wall to measure MI in the rectum, left, transverse, and right colon. In patients with IBD, MI measurements and biopsies were taken in areas which appeared inflamed when present. We then determined if there was a significant difference in MI between patients with IBD and controls. RESULTS: MI was significantly higher in the rectum of patients with IBD (CD and UC combined) versus control colons [767 (618-991) vs. 531 (418-604) ohms, P < 0.01]. There were no significant differences in MI among patients with IBD versus controls in the right, transverse, or left colon. Within the IBD group, there were no significant differences in MI between inflamed versus non-inflamed rectums. There was no correlation between quality of life scores or endoscopic severity with MI, though this study was likely underpowered to detect these differences. CONCLUSION: Rectal MI is significantly higher in patients with IBD versus controls. Future studies are needed to determine how this information can be used clinically.

Mechanisms, Evaluation, and Management of Chronic Constipation.

With a worldwide prevalence of 15%, chronic constipation is one of the most frequent gastrointestinal diagnoses made in ambulatory medicine clinics, and is a common source cause for referrals to gastroenterologists and colorectal surgeons in the United States. Symptoms vary among patients; straining, incomplete evacuation, and a sense of anorectal blockage are just as important as decreased stool frequency. Chronic constipation is either a primary disorder (such as normal transit, slow transit, or defecatory disorders) or a secondary one (due to medications or, in rare cases, anatomic alterations). Colonic sensorimotor disturbances and pelvic floor dysfunction (such as defecatory disorders) are the most widely recognized pathogenic mechanisms. Guided by efficacy and cost, management of constipation should begin with dietary fiber supplementation and stimulant and/or osmotic laxatives, as appropriate, followed, if necessary, by intestinal secretagogues and/or prokinetic agents. Peripherally acting µ-opiate antagonists are another option for opioid-induced constipation. Anorectal tests to evaluate for defecatory disorders should be performed in patients who do not respond to over-the-counter agents. Colonic transit, followed if necessary with assessment of colonic motility with manometry and/or a barostat, can identify colonic dysmotility. Defecatory disorders often respond to biofeedback therapy. For specific patients, slow-transit constipation may necessitate a colectomy. No studies have compared inexpensive laxatives with newer drugs with different mechanisms. We review the mechanisms, evaluation, and management of chronic constipation. We discuss the importance of meticulous analyses of patient history and physical examination, advantages and disadvantages of diagnostic testing, guidance for individualized treatment, and management of medically refractory patients.

Volumetric Rectal Perception Testing: Is It Clinically Relevant? Results From a Large Patient Cohort.

INTRODUCTION: Rectal perception testing is a recommended component of anorectal physiology testing. Although recent consensus (London) guidelines suggested criteria for categorizing hyporectal and hyper-rectal sensitivity, these were based on scant evidence. Moreover, data regarding diagnostic capabilities and clinical utility of rectal perception testing are lacking. The aims of this study were to determine the association between rectal perception testing and both clinical and physiological variables to enhance the analysis and interpretation of real-life test results. METHODS: Prospectively documented data from 1,618 (92% female) patients referred for anorectal physiology testing were analyzed for 3 rectal perception thresholds (first, urge, and maximal tolerated). Normal values derived from healthy female subjects were used to categorize each threshold into hyposensitive and hypersensitive to examine the clinical relevance of this categorization. RESULTS: There was poor to moderate agreement between the 3 thresholds. Older age, male sex, and constipation were associated with higher perception thresholds, whereas irritable bowel syndrome, fecal incontinence, connective tissue disease, and pelvic radiation were associated with lower perception thresholds to some, but not all, thresholds (P < 0.01 on multivariate analysis for all). The clinical utility and limitations of categorizing thresholds into "hypersensitivity" and "hyposensitivity" were determined. DISCUSSION: Commonly practiced rectal perception testing is correlated with several disease states and thus has clinical relevance. However, most disease states were correlated with 2 or even only 1 abnormal threshold, and agreement between thresholds was limited. This may suggest each threshold measures different pathophysiological pathways. We suggest all 3 thresholds be measured and reported separately in routine clinical testing.

Clinical Impact of Rectal Hyposensitivity: A Cross-Sectional Study of 2,876 Patients With Refractory Functional Constipation.

INTRODUCTION: Normal bowel function requires intact sensory pathways. Diminished rectal sensation (rectal hyposensitivity [RH]) is associated with constipation, although its clinical importance remains unclear. METHODS: Consecutive patients (aged 18-80) attending a tertiary center (2004-2016) for investigation of refractory functional constipation (Rome IV core criteria defined, applied post hoc) were included. Patients completed a clinical symptom questionnaire and underwent anorectal physiologic investigations, including rectal sensory testing (balloon distension) to determine 3 well-established sensory thresholds. Multivariate regression analyses were performed to evaluate associations between RH, symptomology, and allied physiologic investigations. RESULTS: Of 2,876 patients meeting inclusion criteria, 722 (25%) had RH based on ≥1 elevated sensory thresholds (0: n = 2,154 [74.9%]; 1: n = 327 [11.4%]; 2: n = 209 [7.3%]; and 3: n = 186 [6.5%]). A linear relationship existed between increasing number of elevated sensory thresholds and constipation severity (Cleveland Clinic constipation score: mean difference per threshold [95% confidence interval] 0.69 [0.48-0.90]; P < 0.001). Several symptoms were significantly (P < 0.05) associated with RH including: infrequent defecation (odds ratio 1.29 [1.17-1.42]), painful evacuation (1.15 [1.05-1.27]), prolonged toileting (1.14 [1.05-1.24]), and digitation or enema use (1.18 [1.08-1.30]). On defecography, a "functional" evacuation disorder was also associated with RH (1.37 [1.25-1.50], P < 0.001), as was megarectum (2.52 [2.08-3.05], P < 0.001). DISCUSSION: RH occurs in 25% of patients with refractory functional constipation. Increased number of elevated sensory thresholds is associated with more severe constipation phenotype. These data, in the largest study to date, provide for the first time evidence to show that RH is a major pathophysiologic mechanism in constipation, with recognized clinical impact (http://links.lww.com/AJG/B765).(Equation is included in full-text article.).

Translumbosacral Neuromodulation Therapy for Fecal Incontinence: A Randomized Frequency Response Trial.

INTRODUCTION: Treatments for fecal incontinence (FI) remain unsatisfactory because they do not remedy the underlying multifactorial dysfunction(s) including anorectal neuropathy. The aim of this study was to investigate the optimal dose frequency, clinical effects, and safety of a novel treatment, translumbosacral neuromodulation therapy (TNT), aimed at improving neuropathy. METHODS: Patients with FI were randomized to receive 6 sessions of weekly TNT treatments consisting of 600 repetitive magnetic stimulations over each of 2 lumbar and 2 sacral sites with either 1, 5, or 15 Hz frequency. Stool diaries, FI severity indices, anorectal neurophysiology and sensorimotor function, and quality of life were compared. Primary outcome measure was the change in FI episodes/week. Responders were patients with ≥50% decrease in weekly FI episodes. RESULTS: Thirty-three patients with FI participated. FI episodes decreased significantly (∆ ±95% confidence interval, 4.2 ± 2.8 (1 Hz); 2 ± 1.7 (5 Hz); 3.4 ± 2.5 (15 Hz); P < 0.02) in all 3 groups when compared with baseline. The 1 Hz group showed a significantly higher (P = 0.04) responder rate (91 ± 9.1%) when compared with the 5 Hz group (36 ± 18.2%) or 15 Hz (55 ± 18.2%); no difference was found between the 5 and 15 Hz groups (P = 0.667). Anal neuropathy, squeeze pressure, and rectal capacity improved significantly only in the 1 Hz (P < 0.05) group compared with baseline, but not in other groups. Quality of life domains improved significantly (P < 0.05) with 1 and 5 Hz groups. No device-related serious adverse events were noted. DISCUSSION: TNT significantly improves FI symptoms in the short term, and the 1 Hz frequency was overall better than 5 and 15 Hz. Both anorectal neuropathy and physiology significantly improved, demonstrating mechanistic improvement. TNT is a promising, novel, safe, efficacious, and noninvasive treatment for FI (see Visual Abstract, Supplementary Digital Content 3, http://links.lww.com/AJG/B598).

Poststroke Constipation Is Associated With Impaired Rectal Sensation.

OBJECTIVES: Constipation is prevalent in individuals after stroke. However, the pathophysiological mechanisms of poststroke constipation remain unclear. This study was designed (i) to investigate the difference in anorectal motility and rectal sensation among stroke patients with constipation, stroke patients without constipation, and healthy controls (HC), (ii) to evaluate the impact of stroke sites on constipation and rectal sensation, (iii) to explore the role of autonomic functions, and (iv) to determine the independent risk factors for poststroke constipation. METHODS: Seventy-one stroke patients and 24 HC were recruited. General information, clinical characteristics, and relevant questionnaires were collected. Meanwhile, an anorectal manometry test was performed to assess functions of anorectal motility and rectal sensation, and an electrocardiogram was recorded to evaluate autonomic functions. RESULTS: (i) Constipation patients exhibited increased rectal sensation thresholds, compared with patients without constipation or HC (P < 0.001). Almost no difference was detected in anorectal motility parameters among 3 groups. Constipation-associated clinical characteristics, such as spontaneous bowel movements, were weakly or moderately correlated with rectal sensation thresholds (P < 0.05 to P < 0.001 for various parameters). (ii) Patients with brainstem lesions had increased prevalence of constipation and first sensation threshold, compared with patients without brainstem lesions (P = 0.045, P = 0.025, respectively). (iii) There was a weak positive correlation between sympathetic activity and stroke severity and a weak negative one between vagal activity and stroke severity. Rectal sensation thresholds were positively and weakly correlated with sympathetic activity but negatively with vagal activity. (iv) The desire of defecation threshold and the physical activity were independent risk factors for poststroke constipation (P = 0.043, P = 0.025, respectively). DISCUSSION: Poststroke constipation is characterized by elevated thresholds for rectal sensation, rather than altered anorectal motility. Patients with brainstem lesions are predisposed to constipation possibly because of the disruption of afferent pathway from the rectum to the brain. Moreover, the desire of defecation threshold and the physical activity level are factors independently associated with poststroke constipation.

Insula Activity to Visceral Stimulation and Endocrine Stress Responses as Associated With Alexithymia in Patients With Irritable Bowel Syndrome.

OBJECTIVE: Few studies have investigated associations between alexithymia and physiological mechanisms in psychosomatic diseases. We examined associations between alexithymia and 1) perception and brain processing of visceral stimulation and 2) the endocrine responses to corticotrophin-releasing hormone (CRH) in healthy individuals and patients with irritable bowel syndrome (IBS). METHODS: The study included 29 patients with IBS and 35 age- and sex-matched healthy controls (HCs). Alexithymia was measured using the 20-item Toronto Alexithymia Scale (TAS-20). Brain responses to rectal distention and its anticipation were measured by functional magnetic resonance imaging and analyzed at a voxel-level threshold of puncorrected < .001 combined with a cluster-level threshold of pFWE-corrected < .05. On a different day, plasma adrenocorticotropic hormone and cortisol responses after intravenous CRH administration were measured. RESULTS: TAS-20 scores did not differ significantly between patients with IBS and HCs (p = .18). TAS-20 scores correlated positively with the individual rectal discomfort thresholds (ßrobust = 0.49, p = .03) and negatively with the rating of fear before rectal distention (ßrobust = -1.63, p = .04) in patients with IBS but not in HCs. Brain responses to rectal distention in the right insula and other brain regions were positively associated with TAS-20 scores to a greater extent in patients with IBS than in HCs. Individuals with higher TAS-20 scores (both patients with IBS and HCs) demonstrated stronger adrenocorticotropic hormone responses to CRH administration (F(4,224) = 3.54, p = .008). CONCLUSION: Higher alexithymia scores are associated with stronger physiological responses, but lower anticipatory fear ratings and higher discomfort thresholds, particularly in patients with IBS.

Colonic transit in patients after anterior resection: prospective, comparative study using single-photon emission CT/CT scintigraphy.

BACKGROUND: Bowel dysfunction after anterior resection is well documented, but its pathophysiology remains poorly understood. No study has assessed whether postoperative variation in colonic transit contributes to symptoms. This study measured colonic transit using planar scintigraphy and single-photon emission CT (SPECT)/CT in patients after anterior resection, stratified according to postoperative bowel function. METHODS: Symptoms were assessed using the low anterior resection syndrome (LARS) score. Following gallium-67 ingestion, scintigraphy was performed at predefined time points. Nine regions of interest were defined, and geometric centre (GC), percentage isotope retained, GC velocity index and colonic half-clearance time (T½ ) determined. Transit parameters were compared between subgroups based on LARS score using receiver operating characteristic (ROC) curve analyses. RESULTS: Fifty patients (37 men; median age 72·6 (range 44·4-87·7) years) underwent planar and SPECT scintigraphy. Overall, 17 patients had major and nine had minor LARS; 24 did not have LARS. There were significant differences in transit profiles between patients with major LARs and those without LARS: GCs were greater (median 5·94 (range 2·35-7·72) versus 4·30 (2·12-6·47) at 32 h; P = 0·015); the percentage retained isotope was lower (median 53·8 (range 6·5-100) versus 89·9 (38·4-100) per cent at 32 h; P = 0·002); GC velocity indices were greater (median 1·70 (range 1·18-1·92) versus 1·45 (0·98-1·80); P = 0·013); and T½ was shorter (median 38·3 (17·0-65·0) versus 57·0 (32·1-160·0) h; P = 0·003). Percentage tracer retained at 32 h best discriminated major LARS from no LARS (area under curve (AUC) 0·828). CONCLUSION: Patients with major LARS had accelerated colonic transit compared with those without LARS, which may help explain postoperative bowel dysfunction in this group. The percentage tracer retained at 32 h had the greatest AUC value in discriminating such patients.

ANTECEDENTES: La disfunción intestinal después de la resección anterior (anterior resection, AR) está bien documentada, pero su fisiopatología sigue siendo poco conocida. Ningún estudio ha evaluado si la variación postoperatoria en el tránsito colónico contribuye a los síntomas. Este estudio midió el tránsito colónico mediante gammagrafía planar con SPECT/CT en pacientes después de una AR, estratificados según la función intestinal postoperatoria. MÉTODOS: Los síntomas se evaluaron mediante el sistema de puntuación del síndrome de resección anterior baja (low anterior resection syndrome, LARS). Después de la administración oral de galio-67, se realizó una gammagrafía en tiempos predefinidos. Se establecieron nueve regiones de interés y se midió/calculó las siguientes variables: (i) centro geométrico (geometric centre, GC); (ii) porcentaje de isótopo retenido; (iii) velocidad del GC; y (iv) semivida de aclaramiento del colon (T1/2). Se compararon los parámetros de tránsito en diferentes subgrupos de pacientes de acuerdo con su puntuación LARS utilizando análisis de curva ROC RESULTADOS: La gammagrafía planar con SPECT se realizó en 50 pacientes con AR seleccionados al azar (37 varones, media de 72,3 años (DE 9,0)). En total, 17 pacientes presentaban un LARS mayor, 9 tenían un LARS menor y 24 no presentaban LARS. En comparación con los pacientes sin LARS, los pacientes con LARS mayor tenían perfiles de tránsito significativamente diferentes: a las 32 horas, (i) los GC fueron mayores (mediana 5,94 (rango 2,35-7,72) versus 4,30 (2,12-6,47), P = 0,015)); (ii) el porcentaje de isótopo retenido fue menor (mediana 53,8% (error estándar de la media 6,5) versus 89,9% (3,4), P = 0,002)); (iii) las velocidades del GC fueron mayores (1,70 (1,18-1,92) versus 1,45 (0,98-1,80), P = 0,013)); y (iv) las semividas T1/2 fueron más cortas (38,3 horas (17,0-65,0) versus 57,0 (32,1-160), P = 0,003)). El porcentaje de isótopo retenido a las 32 horas fue el parámetro que mejor discriminó los pacientes con LARS mayor de los pacientes sin LARS (AUC 0,828). CONCLUSIÓN: Los pacientes con LARS mayor presentaron un tránsito colónico acelerado en comparación con los pacientes sin LARS, lo que puede contribuir a explicar la disfunción intestinal postoperatoria en dichos pacientes. El marcador de porcentaje de isótopo retenido a las 32 horas tenía un valor de AUC más elevado en la discriminación de estos pacientes.

Functional complaints and quality of life after transanal total mesorectal excision: a meta-analysis.

BACKGROUND: Total mesorectal excision (TME) gives excellent oncological results in rectal cancer treatment, but patients may experience functional problems. A novel approach to performing TME is by single-port transanal minimally invasive surgery. This systematic review evaluated the functional outcomes and quality of life after transanal and laparoscopic TME. METHODS: A comprehensive search in PubMed, the Cochrane Library, Embase and the trial registers was conducted in May 2019. PRISMA guidelines were used. Data for meta-analysis were pooled using a random-effects model. RESULTS: A total of 11 660 studies were identified, from which 14 studies and six conference abstracts involving 846 patients (599 transanal TME, 247 laparoscopic TME) were included. A substantial number of patients experienced functional problems consistent with low anterior resection syndrome (LARS). Meta-analysis found no significant difference in major LARS between the two approaches (risk ratio 1·13, 95 per cent c.i. 0·94 to 1·35; P = 0·18). However, major heterogeneity was present in the studies together with poor reporting of functional baseline assessment. CONCLUSION: No differences in function were observed between transanal and laparoscopic TME.

ANTECEDENTES: La escisión total del mesorrecto (total mesorectal excision, TME) proporciona excelentes resultados oncológicos en el tratamiento del cáncer de recto, pero los pacientes pueden presentar trastornos funcionales. Un abordaje novedoso para realizar la TME es mediante cirugía transanal mínimamente invasiva de puerto único. En esta revisión sistemática se evaluaron los resultados funcionales y la calidad de vida después de TME transanal (TaTME) y TME laparoscópica (LapTME). MÉTODOS: En mayo de 2019 se realizó una búsqueda exhaustiva en las bases de datos de Pubmed, Biblioteca Cochrane, EMBASE y en los registros de ensayos clínicos. Se utilizaron las guías PRISMA. Los datos para el metaanálisis se agruparon utilizando un modelo de efectos aleatorios. RESULTADOS: Se identificaron un total de 11.660 estudios, de los cuales se incluyeron 14 estudios y 6 resúmenes de congresos con 846 pacientes (599 TaTME/247 LapTME). Un número sustancial de pacientes presentó trastornos funcionales consistentes con el síndrome de resección anterior baja (low anterior resection syndrome, LARS). El metaanálisis no encontró diferencias significativas en los porcentajes de LARS grave entre los dos abordajes (razón de oportunidades, odds ratio, OR 1,13; i.c. del 95% 0,94-1,35; P = 0,18). Sin embargo, los estudios globalmente presentaron una gran heterogeneidad, así como una deficiente información sobre la evaluación funcional basal. CONCLUSIÓN: No se observaron diferencias en la función entre TaTME y LapTME.

Visceral pain from colon and rectum: the mechanotransduction and biomechanics.

Visceral pain is the cardinal symptom of functional gastrointestinal (GI) disorders such as the irritable bowel syndrome (IBS) and the leading cause of patients' visit to gastroenterologists. IBS-related visceral pain usually arises from the distal colon and rectum (colorectum), an intraluminal environment that differs greatly from environment outside the body in chemical, biological, thermal, and mechanical conditions. Accordingly, visceral pain is different from cutaneous pain in several key psychophysical characteristics, which likely underlies the unsatisfactory management of visceral pain by drugs developed for other types of pain. Colorectal visceral pain is usually elicited from mechanical distension/stretch, rather than from heating, cutting, pinching, or piercing that usually evoke pain from the skin. Thus, mechanotransduction, i.e., the encoding of colorectal mechanical stimuli by sensory afferents, is crucial to the underlying mechanisms of GI-related visceral pain. This review will focus on colorectal mechanotransduction, the process of converting colorectal mechanical stimuli into trains of action potentials by the sensory afferents to inform the central nervous system (CNS). We will summarize neurophysiological studies on afferent encoding of colorectal mechanical stimuli, highlight recent advances in our understanding of colorectal biomechanics that plays critical roles in mechanotransduction, and review studies on mechano-sensitive ion channels in colorectal afferents. This review calls for focused attention on targeting colorectal mechanotransduction as a new strategy for managing visceral pain, which can also have an added benefit of limited CNS side effects, because mechanotransduction arises from peripheral organs.