Rectal Sensation Research Articles

Chinese expert consensus on clinical diagnosis and treatment of fecal incontinence (2022 edition)

Fecal incontinence is one of the common diseases in the field of colorectal and anal surgery. Its etiology is complex, the treatment response is suboptimal, and there are controversies in clinical care. There is no consensus on the clinical practice of fecal incontinence in China currently. Launched by Anorectal Branch of Chinese Medical Doctor Association, Expert Committee on Anorectal Disease of Anorectal Branch of Chinese Medical Doctor Association, and Clinical Guidelines Committee of Anorectal Branch of Chinese Medical Doctor Association, and organized by the editorial board of Chinese Journal of Gastrointestinal Surgery, Chinese experts on this field were convened to write the Chinese expert consensus on clinical practice of fecal incontinence based on relevant references. After rounds of discussion, the final consensus combines the latest evidence and experts' clinical experience. This expert group suggested that a comprehensive assessment of fecal incontinence should be conducted before treatment, including medical history, relevant scales, physical examination and special examinations. Special examinations include anorectal endoscopy, anorectal manometry, transrectal ultrasound, magnetic resonance, rectal sensation and compliance, balloon ejection test, pelvic floor electromyography, defecography, colonoscopy and pudendal nerve terminal motor latency. Treatment methods include life style modification, medication, surgery, traditional Chinese medicine and other treatments. This consensus aims to standardize the algorithm of fecal incontinence management and improve therapeutic efficacy.

Slow, deep breathing intervention improved symptoms and altered rectal sensitivity in patients with constipation-predominant irritable bowel syndrome.

Limited treatment options have been shown to alter the natural course of irritable bowel syndrome (IBS). Slow, deep breathing (SDB) is a common pain self-management intervention. This pilot study aimed to explore the impact of SDB on measures of autonomic and anorectal functions as well as patient-reported symptoms in constipation-predominant IBS (IBS-C). Eighty-five IBS-C patients were enrolled in this study and randomly assigned to the experimental group (Group A, n = 42) and the control group (Group B, n = 43). SDB was conducted at six breathing cycles per minute with an inhalation for 4 s and exhalation for 6 s at a ratio of 2:3 and repeated for 30 min during the intervention. All subjects underwent high-resolution anorectal manometry (HRAM) and completed the standardized IBS symptom severity system (IBS-SSS) questionnaire. Meanwhile, changes in stool consistency, weekly frequency of complete spontaneous bowel movements (CSBMs), and weekly frequency of spontaneous bowel movements (SBMs) were recorded. All IBS-C patients received electrocardiogram (ECG) recordings for heart rate variability (HRV) analysis at baseline, weeks 3, 6. At baseline, no differences were found between Groups A and B. The IBS-SSS score and its five sub-scores of Group B patients were significantly higher at week 6 than those of Group A patients (all p < 0.001). Furthermore, compared with Group B patients, Group A patients had a significantly higher threshold volume for the first sensation (p < 0.001), desire to defecate (p = 0.017), and maximum tolerable volume (p = 0.018) at week 6 of the SDB treatment. We also noted significant improvements in stool consistency (p = 0.002), weekly SBM frequencies (p < 0.001), and weekly CSBM frequencies (p = 0.018) of Group A patients at week 6 when compared with Group B patients. Finally, the corrected high frequency (HF) of Group A patients was significantly higher than the HF of Group B patients at week 3 (p < 0.001) and at week 6 (p < 0.001). Likewise, patients in Group A had a significantly higher root mean square of the successive differences (RMSSD) than that of patients in Group B at week 3 (p < 0.001) and at week 6 (p < 0.001). We found that a 6-week SDB intervention improved symptoms and altered rectal sensation in IBS-C patients. Moreover, SDB enhanced vagal activity. These findings suggest that the effect of SDB on IBS-C may be due to mechanisms involving autonomic responses.

Reproducibility of high-resolution manometry among healthy and constipated persons.

Although high-resolution manometry (HR_ARM) is commonly used to diagnose defecatory disorders, its intraindividual day-to-day reproducibility is unknown. Since these measurements entail voluntary effort, this study aimed to evaluate the intraindividual day-to-day reproducibility of HR_ARM. In 22 healthy women (35 years [14] mean [SD]) and 53 constipated patients(42 years [13], 46 women), the rectal balloon expulsion time (BET), and anorectal pressures were measured with HR_ARM on 2 days separated by a median (interquartile range) of 15 days (11-53) in healthy and 40 days (8-75) in constipated patients. Anorectal pressures were evaluated at rest (20 s), during squeeze, and duringevacuation. Rectal sensation was also evaluated in constipated patients. The agreement between both measurements was evaluated with Lin's concordance correlation coefficient (CCC) and other tests. Among constipated patients, the anal resting (mean CCC [95%CI] 0.62 [0.43-0.76]) and squeeze pressures (CCC 0.65 [0.47-0.79]), rectoanal gradient during evacuation (CCC 0.42 [0.17-0.62]), and rectal sensory thresholds (CCC for urgency 0.72 [0.52-0.84]) were concordant. Between days 1 and 2, one or more outcomes, characterized as normal or abnormal, differed in 79% of constipated patients, i.e., anal resting and squeeze pressures, the gradient, and the rectal BET differed in, respectively, 25%, 19%, 36%, and 10% of constipated patients. The rectal BET was prolonged in three healthy persons (both days) and either on 1 day (six patients) or 2 days (33 patients) in constipated patients. While HR_ARM variables and the BET are reproducible within healthy and constipated persons, the outcome on repeat testing differed in 79% of constipated patients.

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

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. 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). 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. 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.

Normal Values of High-resolution Anorectal Manometry of Healthy Indians

Background/AimsHigh-resolution anorectal manometry (HRAM) measures anal sphincter function and anorectal co-ordination. This study aims to provide normal data for HRAM and evaluate the effect of gender, age, and body mass index (BMI) on anorectal functions in healthy Indian subjects.MethodsHRAM was performed on 93 healthy volunteers using a 20-channel, water-perfused catheter. We evaluated anorectal pressures, rectal sensation, and balloon expulsion time. Measurements were recorded during rest, squeeze, and simulated defecation (push).ResultsMedian anal resting pressure (88 mmHg vs 94 mmHg, P = NS), anal squeeze pressure (165 mmHg vs 147 mmHg, P = NS) were not significantly different between males and females. Rectal pressure (70 mmHg vs 54 mmHg, P = 0.024) and anal pressure (82 mmHg vs 63 mmHg, P = 0.008) during simulated evacuation without rectal distention, were higher in males. The threshold for the first sensation was lower in females (40 mL vs 30 mL, P = 0.021) but desire to defecate (105 mL vs 90 mL, P = NS) and maximum tolerable volume (160 mL vs 140 mL, P = NS) were not significantly different in males and females. Anal residual pressure (median mmHg 83 vs 71 mmHg, P = 0.025) was higher in subjects < 40 years of age. Maximum anal squeeze pressure (185 mmHg vs 165 mmHg, P = 0.024) and maximum rectal pressure (75 mmHg vs 62 mmHg, P = 0.032) during push higher in BMI < 23 kg/m2.ConclusionsThe present study provides normal data for the Indian population that can be used for comparison and further work. Age, gender, and BMI affect anorectal parameters in HRAM and should be considered while reporting.

Utility of postoperative anorectal manometry in children with anorectal malformation: a systematic review.

Children with anorectal malformation (ARM) often continue to have disturbances in bowel function long after reconstructive surgery. Anorectal manometry may be utilized to evaluate bowel function in these children. We aimed to describe the reported protocols and manometric findings in children with ARM post-reconstructive surgery and to investigate the correlation between manometric evaluation and bowel functional outcome. PubMed, EMBASE, and Google Scholar databases were searched from 1980 to 2021. Data were reviewed and extracted independently by two authors, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Included studies were English articles reporting postoperative assessment of children (≤ 18years) with ARM using anorectal manometry. From 128 articles obtained in the initial search, five retrospective cohort studies and one prospective study fulfilled inclusion criteria. The rectoanal inhibitory reflex and mean anal resting pressure were parameters most often reported to correlate with postoperative bowel function. The least reported parameters among the studies were high-pressure zone, rectal volume, and rectal sensation. Anorectal manometry could be an objective method providing important information for personalized management of postoperative ARM patients with bowel function issues, but lack of standardized protocols limits a comprehensive analysis of their utility.

Transcutaneous Electrical Acustimulation Improves Irritable Bowel Syndrome With Constipation by Accelerating Colon Transit and Reducing Rectal Sensation Using Autonomic Mechanisms.

Slow colon transit and visceral hypersensitivity are recognized as major pathophysiological mechanisms in irritable bowel syndrome with constipation (IBS-C). However, there is a lack of therapies targeting both abdominal pain and colonic motility. This study was designed to investigate the long-term effects and possible mechanisms of transcutaneous electrical acustimulation (TEA) in patients with IBS-C. Fifty-two patients with IBS-C were randomized into 2 groups: daily TEA for 4 weeks (n = 26) and daily sham-TEA for 4 weeks (n = 26). The number of complete spontaneous bowel movements per week (CSBMs/week, primary outcome), Irritable Bowel Syndrome Severity Scoring System, Patient Assessment of Constipation Quality of Life, visual analog scale (VAS) pain score, colonic transit time, and anorectal physiology were evaluated before treatment and at the end of the treatment. Colonic transit was assessed with radiopaque markers. Electrocardiograms were recorded for assessing autonomic functions. (i) TEA improved constipation and abdominal pain. After the treatment, the number of CSBMs/week during the last week in the TEA group was higher than that in the sham-TEA group (3.5 ± 1.6 vs 2.3 ± 0.6, P = 0.002). Similar effects were also noted in the visual analog scale pain score ( P = 0.002) and Irritable Bowel Syndrome Severity Scoring System score ( P = 0.025). In addition, there was a significant improvement in the quality of life of patients with constipation. The Patient Assessment of Constipation Quality of Life total score was significantly decreased in the TEA group ( P = 0.004). (ii) Compared with sham-TEA, TEA improved colon transit ( P = 0.002) and increased the threshold of rectal sensation (desire to defecate, P = 0.004; maximum tolerability, P &lt; 0.001). (iii) TEA increased vagal activity, compared with sham-TEA ( P &lt; 0.05); at the end of the treatment, the vagal activity was significantly correlated with colon transit and the CSBMs/week. TEA improves constipation and symptoms of IBS by accelerating colon transit and reducing rectal sensation, possibly mediated by using the autonomic mechanisms.

ID:15782 Dorsal Root Ganglion Stimulation for Chronic Penile Pain and Fecal Urge With Incontinence

We present the case of a 58-year-old man who underwent DRG stimulation for chronic penile pain with unexpected resolution of fecal urge with incontinence. He initially presented with 8 months of penile pain, 10 years of fecal urgency, and 5 years of fecal incontinence. He had minimal benefit with pelvic physical therapy, Sitz baths, and medications via oral, transdermal, and rectal routes. Magnetic resonance imaging (MRI) lumbar neurogram was unremarkable, and MRI total spine was notable for severe right neuroforaminal narrowing at L4-5. Anorectal manometry and pudendal nerve terminal motor latency testing revealed signs of pelvic floor dyssynergia, including paradoxical puborectalis muscle contraction with Valsalva maneuver and altered rectal sensation. He had minimal relief with bilateral pudendal nerve blocks, left S2 and S3 selective nerve root blocks, and trigger point injections of the left puborectalis muscle.

Biofeedback therapy for anorectal functional disorder: Malaysian colorectal tertiary centre experience

BackgroundAnorectal functional disorder encompasses arrays of conditions including Obstructive Defecation Syndrome (ODS) and Fecal Incontinence (FI). Biofeedback Therapy (BFT) serves as first line therapy to re-train pelvic floor coordination, rectal sensation and strengthening pelvic floor muscle. The aim of this study is determining the efficacy of BFT in our centre. MethodsThis is a retrospective observational cohort study of patients attended biofeedback therapy session from January 2013 to December 2018. Descriptive statistic was used to analyse the data. ResultTotal 99 patients with mean age of 44.6 ± 18.1 with female 56% (n = 55) and male 44% (n = 44) attended BFT session. Overall, 77 had CC (77%) and 23 (23%) had FI. Mean number of sessions was 11.8. Overall improvement rate 42 (42%), no improvement 32 (32%) and defaulted 26 (26%). In patients with CC, 32 (41.6%) had improvement in symptoms, 23 (29.9%) had no improvements, 22 (28.6%) defaulted BFT.Patients with FI, 7 (30.4%) had Obstetric Sphincter Injury, 7 (30.4%) had traumatic anal injury, 3 (13.0%) has Low Anterior Resection Syndrome, 2 (8.7%) had sphincter injury following anal sepsis, 2 (13.0%) had rectocele repair and 1 (4.3%) were idiopathic. 9 patients (39.1%) had stoma created. Overall response rate was: 10 patients (43.5%) had improvement in symptoms, 9 patients (39.1%) had no improvement, 4 patients (17.4%) defaulted therapy. ConclusionOur outcome rate is lower compared to published due the limited access and logistic restrictions. This issue should be given great consideration such as broadening the service and training.

Comparison of biochemical, microbial and mucosal mRNA expression in bile acid diarrhoea and irritable bowel syndrome with diarrhoea

ObjectiveThere are altered mucosal functions in irritable bowel syndrome with diarrhoea (IBS-D); ~30% of patients with IBS-D have abnormal bile acid (BA) metabolism (ABAM) and diarrhoea (summarised as BAD).AimTo compare...

Diagnostic Strategy and Tools for Identifying Defecatory Disorders.

This article reviews the indications, techniques, interpretation, strengths, and weaknesses of tests (anal manometry, anal surface electromyography, rectal balloon expulsion test, barium and MRI defecography, assessment of rectal compliance and sensation, and colonic transit) that are used diagnose defecatory disorders in constipated patients. The selection of tests and the sequence in which they are performed should be individualized to and interpreted in the context of the clinical features. Because anorectal functions are affected by age, results should be interpreted with reference to age- and sex-matched normal values for the same technique.

Review of the indications, methods, and clinical utility of anorectal manometry and the rectal balloon expulsion test.

Anorectal manometry (ARM) comprehensively assesses anorectal sensorimotor functions. This review examines the indications, techniques, interpretation, strengths, and weaknesses of high-resolution ARM (HR-ARM), 3-dimensional high-resolution anorectal manometry (3D-HR-ARM), and portable ARM, and other assessments (i.e., rectal sensation and rectal balloon expulsion test) that are performed alongside manometry. It is based on a literature search of articles related to ARM in adults. HR-ARM and 3D-HR-ARM are useful for diagnosing defecatory disorders (DD), to identify anorectal sensorimotor dysfunction and guide management in patients with fecal incontinence (FI), constipation, megacolon, and megarectum; and to screen for anorectal structural (e.g., rectal intussusception) abnormalities. The rectal balloon expulsion test is a useful, low-cost, radiation-free, outpatient assessment tool for impaired evacuation that is performed and interpreted in conjunction with ARM. The anorectal function tests should be interpreted with reference to age- and sex-matched normal values, clinical features, and results of other tests. A larger database of technique-specific normal values and newer paradigms of analyzing anorectal pressure profiles will increase the precision and diagnostic utility of HR-ARM for identifying abnormal mechanisms of defecation and continence.

Anorectal dysfunction after radical cystectomy for bladder cancer

Objective: To prospectively assess anorectal dysfunction using patient-reported outcomes using validated questionnaires, manovolumetry and endoanal ultrasound before and 12 months after RC. Patients and methods: From 2014 to 2019, we prospectively included 44 patients scheduled for RC. Preoperatively and 12 months after surgery, 41 patients filled in a low anterior resection syndrome score (LARS-score) to assess fecal incontinence, increased frequency, urgency and emptying difficulties and a St Mark’s score to assess fecal incontinence in conjunction with manovolumetry and endoanal ultrasound examinations. Pre- and postoperative patient-reported anorectal dysfunction were assessed by LARS-score and St Marks’s score. At the same time-points, anorectal function was evaluated by measuring mean anal resting and maximal squeeze pressures, volumes and pressures at first desire, urgency to defecate and maximum toleration during manovolumetry. Wilcoxon's signed rank test was used to compare pre- and postoperative outcomes by questionnaires. Results: Postoperatively 6/41 (15%) patients reported flatus incontinence assessed by the LARS-questionnaire, and correspondingly the St Mark’s score increased postoperatively. The median anal resting pressure decreased from 57 mmHg preoperatively to 46 mmHg after RC, but without any postoperative anatomic defects detected by endoanal ultrasound. Volumes and pressures at first desire, urgency to defecate and maximum toleration during manovolumetry all increased after RC, indicating decreased postoperative rectal sensation, as rectal compliance was unaltered. Conclusions: Postoperative flatus incontinence is reported by one out of seven patients after RC, which corresponds to decreased anal resting pressures. The finding of decreased rectal sensation might also contribute to patient-reported symptoms and anorectal dysfunction after RC.

Evaluation of Anorectal Function in Perianal Crohn's Disease: A Pilot Study.

Background: Perianal Crohn’s disease is a disabling condition, with little known about anorectal function in healed/inactive perianal Crohn’s disease; Aim: To evaluate anorectal function in a cohort of patients with treated/healed perianal Crohn’s disease; Methods: Prospective cohort study, including high-resolution anorectal manometry, balloon expulsion test, and 3D-endoanal ultrasound in all patients; Results: Of the 16 patients studied (mean age ± SD, 42 ± 13 years), 12 (75%) were men. A laceration of the internal anal sphincter and/or anal scarring was seen in nine (56%) patients; there was no laceration of the external anal sphincter. Five (56%) of these nine patients had never experienced faecal incontinence. All had normal anal resting and squeeze pressures. Manometry suggested dyssynergia in 11 (69%) patients, with only one (6%) fulfilling the criteria for obstructed defecation. Hyposensitivity for at least one sensory parameter was seen in 11 (69%) patients and hypersensitivity in five (31%) patients; Conclusions: This study detected sphincter abnormalities in more than half of patients, many of whom were asymptomatic. Alterations in rectal sensation were frequently seen, more commonly with rectal hyposensitivity. Trial registration: ClinicalTrials.gov (NCT03819257).

Opioid-Associated Anorectal Dysfunction in Chronic Constipation.

The role of anorectal and defecatory dysfunction in opioid-related constipation is unclear. We aimed to evaluate the relationship between opioid use and rectal sensation, defecatory function, and balloon expulsion on anorectal physiology testing. This was a retrospective cohort study of consecutive adults undergoing high-resolution anorectal manometry (HRAM) at a tertiary center for constipation. Clinical characteristics, medication use, and HRAM findings were obtained. Statistical analyses were performed using Fisher-exact/student t-test for univariate analyses and logistic/general linear regression for multivariable analyses to compare patients with no opioid use, recent (< 3months) use, and distant (> 3months) use. 424 patients (49.8 ± 17.2years; 85.6% female) were included. Compared to those without opioid history, patients with recent use had increased volumes for first rectal sensation (70.4mL vs 59.4, p = 0.043), urge (120.5mL vs 101.5, p = 0.017), and maximal tolerance (170.2mL vs 147.2, p = 0.0018), but not patients with distant use. Recent opioid use was associated with increased risk of dyssynergic defecation (DD) (61.8% vs 46.4%, p = 0.035), but not failed balloon expulsion. On multivariable models controlling for potential confounders, recent opioid use, but not distant use, remained independently correlated with increased volumes for first rectal sensation (β-coefficient 9.78, p = 0.019), urge (β-coefficient 16.7, p = 0.0060), and maximal tolerance (β-coefficient 22.9, p = 0.0032), and higher risk for DD (aOR = 2.18, p = 0.026). Recent opioid use was an independent risk factor for rectal hyposensitivity and DD on HRAM in patients with constipation, but that effect may decrease with discontinuation of use. Anorectal physiology testing should be considered in patients with opioid-associated constipation.

Diagnosis of Functional Gastrointestinal Disorders and Choice of Treatment Regimen in Constipation Patients

Aim. A practical review of functional gastrointestinal disorder diagnosis in constipation patients and the rationale for opting treatment.Key points. Functional constipation commonly afflicts different ages and negatively impacts the quality of life. The current diagnostic algorithm in chronic constipation includes the disease identification according to Rome Criteria IV, red-flag symptom detection and instrumental laboratory examination. Functional constipation is notably often associated with anorectal abnormalities that bear a diagnostic value to elaborate an apt treatment strategy. Anorectal manometry, rectal sensation and balloon expulsion tests are the well-studied and significant probing techniques for objective anorectal zone sensorimotor function assessment in patients with functional constipation. The article reviews modern diagnostic methods in functional defecation disorders.Conclusion. The examination and treatment algorithms presented will help improve diagnosis and apply the most suitable management in a constipation-associated functional digestive pathology.

Gastrointestinal Bleeds.

Gastrointestinal Bleeds.

Intestinal chemosensitivity in irritable bowel syndrome associates with small intestinal TRPV channel expression.

Irritable bowel syndrome (IBS) patients often experience meal-associated symptoms. However, the underlying mechanisms are unclear. To determine small intestinal mechanisms of lipid-induced symptoms and rectal hypersensitivity in IBS METHODS: We recruited 26 IBS patients (12 IBS-C, 14 IBS-D) and 15 healthy volunteers (HV). In vivo permeability was assessed using saccharide excretion assay. Rectal sensitivity was assessed using a barostat before and after small bowel lipid infusion; symptoms were assessed throughout. Next, an extended upper endoscopy with probe-based confocal laser endomicroscopy (pCLE) was performed with changes induced by lipids. Duodenal and jejunal mucosal biopsies were obtained for transcriptomics. Following lipid infusion, a higher proportion of HV than IBS patients reported no pain, no nausea, no fullness and no urgency (P<0.05 for all). In a model adjusted for sex and anxiety, IBS-C and IBS-D patients had lower thresholds for first rectal sensation (P=0.0007) and pain (P=0.004) than HV. In vivo small intestinal permeability and mean pCLE scores were similar between IBS patients and HV. Post-lipid, pCLE scores were higher than pre-lipid but were not different between groups. Baseline duodenal transient receptor potential vanilloid (TRPV) 1 and 3 expression was increased in IBS-D, and TRPV3 in IBS-C. Duodenal TRPV1 expression correlated with abdominal pain (r=0.51, FDR=0.01), and inversely with first rectal sensation (r=-0.48, FDR=0.01) and pain (r=-0.41, FDR=0.02) thresholds. Lipid infusion elicits a greater symptom response in IBS patients than HV, which is associated with small intestinal expression of TRPV channels. TRPV-mediated small intestinal chemosensitivity may mediate post-meal symptoms in IBS.

Barostat or syringe-assisted sensory biofeedback training for constipation with rectal hyposensitivity: A randomized controlled trial.

Rectal hyposensitivity (RH) is a well-known pathophysiological dysfunction in chronic constipation. Whether biofeedback training improves RH and restores bowel function is unknown. To investigate the efficacy of barostat-assisted sensory training (BAST) with syringe-assisted sensory training (SAST) in patients with RH in a randomized controlled trial. Patients with RH and chronic constipation (Rome III) were randomized to receive 6 biweekly sessions of BAST or SAST. Verbal/visual feedback was provided during repeated rectal distensions to improve defecation desire/urge and first sensations with either 10-cm balloon connected to barostat (BAST) or 4-cm balloon connected to syringe and manometry probe (SAST). Sensory thresholds, bowel symptoms, and therapist and patient's rating of treatments were compared. The primary outcome (responders) was the improvement in ≥2sensory thresholds. Sixty-six patients were enrolled: 32 received BAST, 34 received SAST, and 56 completed study. There were significantly more responders in BAST group than SAST (78% vs. 53%, p=0.0320). Rectal sensation normalized in 81% with BAST compared to 56% with SAST (p=0.0270). When compared to baseline, desire and urge to defecate thresholds and bowel satisfaction improved with BAST (p=0.0013; p=0.0002; p=0.0001) and SAST (p=0.0012; p=0.0001; p<0.0001) and number of complete spontaneous bowel movements with BAST (p=0.0029) but without inter-group differences. Therapists rated BAST as superior to SAST (p<0.0001), but patients rated both equally. Sensory biofeedback training was effective and significantly improved rectal sensation and constipation symptoms. Although both techniques were useful, the novel BAST was more efficacious and easier to administer for treating RH.

Ameliorating effects and mechanisms of transcutaneous auricular vagal nerve stimulation on abdominal pain and constipation.

BackgroundAbdominal pain and constipation are 2 main symptoms in patients with constipation-predominant irritable bowel syndrome (IBS-C). This study aimed to investigate the effects and possible mechanisms of transcutaneous auricular vagal nerve stimulation (taVNS) in patients with IBS-C.MethodsForty-two patients with IBS-C were randomized into a 4-week sham-taVNS or taVNS treatment. The primary outcomes were complete spontaneous bowel movements per week (CSBMs/week) and visual analog scale (VAS) for abdominal pain. High-resolution anorectal manometry (HRAM) was performed to evaluate anorectal motor and sensory function. Cytokines and brain gut peptides were analyzed in blood samples. ECG was recorded for the assessment of autonomic function.ResultsCompared with sham-taVNS, (a) taVNS increased CSBMs/week (P = 0.001) and decreased VAS pain score (P = 0.001); (b) improved quality of life (P = 0.020) and decreased IBS symptom score (P = 0.001); (c) improved rectoanal inhibitory reflex (P = 0.014) and improved rectal sensation (P < 0.04); (d) decreased a number of proinflammatory cytokines and serotonin in circulation; and (e) enhanced vagal activity (P = 0.040). The vagal activity was weakly correlated with the CSBMs/week (r = 0.391; P = 0.010) and the VAS pain score (r = –0.347; P = 0.025).ConclusionsNoninvasive taVNS improves both constipation and abdominal pain in patients with IBS-C. The improvement in IBS-C symptoms might be attributed to the integrative effects of taVNS on intestinal functions mediated via the autoimmune mechanisms.Trial registrationwww.chictr.org.cn, no. ChiCTR2000029644.FundingNational Natural Science Foundation of China (grant no. 81970538 for FL).