Rectal Balloon Research Articles

Rectal Distension Increased the Rectoanal Gradient in Patients with Normal Rectal Sensory Function.

Frequent observation of abnormal manometric patterns consistent with dyssynergia in healthy volunteers has warranted the need for reassessment of the current methods to enhance the diagnostic value of anorectal manometry in functional defecatory disorders. Whether rectal distention at simulated evacuation will affect anorectal pressure profile and increase rectoanal gradient is not known. One hundred and eight consecutive patients with chronic constipation, 93 females, median age 53years (interquartile range: 40-65), were studied. Simulated evacuation was performed firstly with empty balloon and subsequently after balloon distention to 50 and 100ml. Anorectal pressures were compared. We also performed subgroup analysis in relation to outcome of balloon expulsion test (BET). In addition, we studied the effect of rectal distension on the rectoanal pressure gradient with respect to rectal sensory function. Rectal balloon distension at simulated evacuation improved rectoanal gradient and decreased the rate of dyssynergia during high-resolution anorectal manometry. In subgroup analysis, the increase in rectoanal gradient and correction of dyssynergia with rectal distension was limited to the patients who had normal BET and normal rectal sensory function. Rate of anal relaxation, residual anal pressures, and rectoanal gradient were significantly different between patients with and without normal BET at 50ml of rectal distension. Rectoanal gradient recorded only after rectal distension, along with BMI and maximum tolerable volumes, could predict BET results independently in patients with chronic constipation. Rectal distension during simulated evacuation will affect the anorectal pressure profile. Increase in rectoanal gradient and correction of dyssynergia was only significant in patients with normal rectal sensory function and normal BET.

Improving the utility of high-resolution manometry for the diagnosis of defecatory disorders in women with chronic constipation.

We compared the utility of existing and modified versions of high-resolution manometry for diagnosing defecatory disorders (DD). In 64 healthy and 136 constipated women, we compared left lateral (LL) and seated manometry, and analyzed with existing (ManoView™) and new methods, for discriminating between constipated patients with normal and prolonged rectal balloon expulsion time (BET). In both positions, the rectoanal gradient (RAG) and, for the new analysis, the pressure topography pattern during evacuation were used to discriminate between constipated patients without and with DD. The BET was prolonged, suggestive of a DD, in 52 patients (38%). During evacuation, rectoanal pressures and the RAG were greater in the seated than the LL position (P≤.001). The new analysis identified 4 rectoanal pressure patterns. In the seated position, the BET was associated with the pattern (P=.0001), being prolonged in, respectively, 45%, 15%, 53%, and 0% of patients with minimal change, anal relaxation, paradoxical contraction, and transmission. Within each pattern, the RAG was greater (ie, less negative, P<.0001) in patients with a normal than a prolonged BET. Compared to the ManoView™ RAG in the LL position, the integrated analysis (ie, pattern and new RAG) in the LL position (P<.01) and the seated ManoView™ gradient (P=.02) were more effective for discriminating between constipated patients without and with DD. Anorectal HRM ideally should be performed in the more physiological seated position and analyzed by a two-tier approach, which incorporates the overall pattern followed by the rectoanal gradient. These findings reinforce the utility of manometry for diagnosing DD.

Effect of electroacupuncture on intestinal epithelial mucosal barrier function in rats with diarrhea-predominant irritable bowel syndrome

To observe the effect of electroacupuncture (EA) on intestinal epithelial mucosal barrier function in diarrhea-predominant irritable bowel syndrome(IBS-D) rats, so as to explore its mechanisms underlying improvement of IBS-D. Forty SD rats (half male and half female) were randomly divided into control, model, EA and medication (Pinaverium Bromide, PB) groups, with 10 rats in each group. The IBS-D model was established by chronic unpredictable mild stress combined with gavage of Senna-leaf solution. EA (2 Hz/15 Hz，0.1-1 mA) was applied to unilateral "Zusanli"(ST36),"Tianshu" (ST25), "Sanyinjiao"(SP6) and "Taichong"(LR3) alternatively for 15 min, once daily for 14 days. Rats of the medication group was treated by gavage of PB (10 mL·kg-1·d-1) for 14 days. The visceral sensitivity (pain) was assessed by using the pressure threshold which the inserted rectal balloon catheter air-inflation (connected to a blood pressure gauge) induced stronger abdominal muscular contraction to force the rat's abdomen to lift the experimental stand surface. The diarrhea index was used to evaluate loose stool grade. The expression of Claudin-1 and Occludin (intestinal epithelial tight junction proteins) of colon tissue was detected by immunohistochemistry. The activity of plasma diamine oxidase (DAO) was assayed by using spectrophotometry. Compared with the control group, the diarrhea index and plasma DAO activity in the model group were significantly increased (P<0.01), while the visceral pain threshold, expression of Claudin-1 and Occludin in the model group were significantly decreased (P<0.01). After the treatment, the diarrhea index and plasma DAO activity were significantly lower in both EA and medication groups than that in the model group (P<0.01), and the visceral pain threshold and expression levels of Claudin-1 and Occludin were obviously increased (P<0.05, P<0.01). No significant differences were found between the EA and medication groups in all the above-mentioned indexes (P>0.05). Electroacupuncture can significantly improve abdominal pain and diarrhea in IBS-D model rats, which may be closely associated with its effects in up-regulating the expression of intestinal epithelial tight junction proteins Claudin-1 and Occludin to restore the function of intestinal epithelial mucosal barrier.

Rectal Hydrogel Spacer Improves Late Gastrointestinal Toxicity Compared to Rectal Balloon Immobilization After Proton Beam Radiation Therapy for Localized Prostate Cancer: A Retrospective Observational Study

Our purpose was to compare dosimetric parameters and late gastrointestinal outcomes between patients treated with proton beam therapy (PBT) for localized prostate cancer with rectal balloon immobilization versus a hydrogel rectal spacer. Patients with localized, clinical stage T1-4 prostate adenocarcinoma were treated at a single institution using conventionally fractionated, dose-escalated PBT from 2013 to 2018. Patient-reported gastrointestinal toxicity was prospectively collected, and the incidence of rectal bleeding was retrospectively reviewed from patient records. One hundred ninety-two patients were treated with rectal balloon immobilization, and 75 were treated with a rectal spacer. Rectal hydrogel spacer significantly improved rectal dosimetry while maintaining excellent target coverage. The 2-year actuarial rate of grade 2+ late rectal bleeding was 19% and 3% in the rectal balloon and hydrogel spacer groups, respectively (P = .003). In univariable analysis, the probability of grade 2+ rectal bleeding was significantly correlated with increasing rectal dose. In multivariable analysis, only receipt of spacer hydrogel (hazard ratio, 0.145; P = .010) and anticoagulation use (hazard ratio, 5.019; P < .001) were significantly associated with grade 2+ bleeding. At 2-year follow-up, patient-reported Expanded Prostate Cancer Index Composite bowel quality of life composite scores were less diminished in the hydrogel spacer group (absolute mean difference, 5.5; P = .030). Use of rectal hydrogel spacer for prostate PBT is associated with a significantly lower incidence of clinically relevant, late rectal bleeding and lower decrement in long-term, patient-reported bowel quality of life compared with rectal balloon immobilization. Our results suggest that hydrogel spacer may improve rectal sparing compared with rectal balloon immobilization during PBT for prostate cancer.

Diagnostic value of the balloon expulsion test compared with anorectal manometry in Indian patients with dyssynergic defecation.

IntroductionDigital rectal examination (DRE) and balloon expulsion test (BET) are simple tests to diagnose dyssynergic defecation (DD).AimTo determine differences in symptoms and manometry findings in patients with abnormal BET and normal BET. The secondary objective was to ascertain the sensitivity and specificity of BET and DRE + BET for the diagnosis of DD in an Indian setting using ARM findings as the gold standard.Material and methodsRetrospective analysis of patients with chronic constipation referred for anorectal manometry (ARM) between December 2012 and March 2019. DD was diagnosed using ARM. Findings on BET and, in a subset of cases, on DRE + BET were compared with ARM findings. The data were analyzed for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Agreement of BET and DRE + BET with ARM was calculated using Cohen’s κ coefficient. A p-value of < 0.05 was considered significant.ResultsA total of 1006 cases (734 males, 73%) formed the study cohort. Patients with abnormal BET more frequently reported digitation, bleeding per rectum, and straining (p < 0.00001). Moreover, they had a significantly higher median basal pressure compared to those with normal BET (80 vs. 67, p = 0.03). DD was significantly more common in those with abnormal BET. The sensitivity, specificity, PPV, and NPV of BET in detecting DD were 28.29%, 97.15%, 81.13%, and 75.78%, respectively. The percentage of agreement was 76.34%, and there was fair degree of correlation between the two tests. In a smaller subset of cases (166), DRE and BET findings were both available for analysis. We noted that the sensitivity, specificity, PPV, and NPV of combined DRE + BET were 57.63%, 88.79%, 73.91%, and 79.17%, respectively. The Cohen’s κ correlation coefficient was 0.49, suggesting moderate agreement.ConclusionsPatients with abnormal BET more frequently report digitation, straining, and bleeding per rectum, and have higher resting anal pressure. BET is a good screening test for DD in an Indian setting.

2113 Biofeedback Therapy With the Rao Protocol for Dyssynergic Defecation Is Effective Among Patients With Inflammatory Bowel Disease

INTRODUCTION: Dyssynergic defecation (DD) symptoms are common in patients with inflammatory bowel disease (IBD). Biofeedback (BFB) is a standard of care treatment for DD, however, few studies have evaluated its efficacy in IBD patients with DD. CASE DESCRIPTION/METHODS: This is a case series that looks at 5 patients with IBD who were enrolled in BFB for DD between 2015 to 2018 at a tertiary referral motility program. All patients had greater than two sessions, survey and high resolution anorectal manometry (HR-ARM) data were collected at baseline and during each DD BFB visit. The Rao protocol for BFB is a physician-led program that consists of an active phase with the number of sessions tailored to each patient’s progress, followed by refresher sessions. A solid state HR-ARM catheter is utilized with sensors in the rectum/pouch and anal canal. Stool retention simulation consists of inflation of a rectal balloon during manometry based BFB. A total of 5 patients were identified for this case series. The average age of the patients was 46 years. Of these 5 patients, 3 had Crohn’s disease and 2 had ulcerative colitis. After completion of BFB, IBD patients experienced a significant improvement in stool form (Bristol stool scale type 2 to 6, P = 0.01), rise in the defecation index (intrarectal/pouch pressure divided by intra-anal pressure during simulated defecation; 0.39 to 0.81, P = 0.04), and complete resolution of DD with a rectal balloon inflated to simulate stool present in the rectum/pouch on final BFB session (P &lt; 0.01). IBD patients did not report a significant improvement in global bowel satisfaction rating on a 10-point Likert scale (2.2 to 3.6, P = 0.22). DISCUSSION: Biofeedback with the Rao protocol in conjunction with use of HR-ARM catheters shows efficacy in the correction of dyssynergia pattern, leading to improvement in objective measures such as defecation index and stool form on diary in IBD patients. Subjective improvement in global bowel satisfaction rating was less than the non-IBD cohort. In conclusion, patients with IBD who are found to have DD should be given consideration for enrollment in a BFB program, which is a labor-intensive approach but has no adverse effects.

121 Opioid Use Are Independently Associated With Rectal Hyposensitivity and Dyssynergic Defecation in Chronic Constipation

INTRODUCTION: The role of defecation dysfunction (DD) and rectal sensitivity in opioid related chronic constipation (CC) is unknown. The purpose of this study is to evaluate the relationship between opioid use and rectal sensation, defecatory function, and balloon expulsion on physiology testing. METHODS: This was a retrospective cohort study of consecutive adult patients who underwent high-resolution anorectal manometry (HRAM) at a tertiary care center for CC. Baseline patient clinical characteristics and HRAM findings were reviewed. Rectal hyposensitivity was defined by increased rectal sensation volume for first sensation, urge, and maximal tolerance. DD was defined by impaired anal sphincter relaxation (&lt;20% decrease from resting pressure) during strain maneuver with or without weak push, defined as inadequate rectal contraction pressure (&lt;40 mmHg increase from baseline). Successful balloon expulsion was defined by evacuation of 50 mL balloon within 2 minutes. Statistical analyses were performed using Fisher exact or student t-test for univariate analyses and logistical or general linear regression for multivariate analyses. RESULTS: 317 patients (mean age 50.3 years; 86.8% female) were included. Patients with recent opioid use (&lt;3 months of HRAM) had significantly increased volume for first rectal sensation (70.4 mL vs 61.5, P = 0.043), urge sensation (120.4 vs 104.5, P = 0.04), and maximal tolerance (170.2 mL vs 149.6, P = 0.0083) when compared to those without recent opioid use. No significant difference in rectal sensation was found in patients with a distant history of opioid use (&gt;3 months) (Figure 1). Patients with recent opioid use also had increased risk of DD (63.4% vs 44.9%, P = 0.029), but no difference in failed balloon expulsion (75.9% vs 74.8%, P = 0.90). On multivariate analyses after controlling for potential confounders including history of irritable bowel syndrome (IBS), age, sex and history of abdominal or pelvic surgeries, recent opioid use (&lt;3 months), but not distant use (&gt;3 months), remained independently associated with increased volume for urge sensation (β-coefficient 14.3, P = 0.03) and maximal tolerance (β-coefficient 22.8, P = 0.006), and higher risk for DD (OR 1.67, P = 0.04) (Table 1). CONCLUSION: Recent opioid use was an independent risk factor for rectal hyposensitivity and DD on HRAM in patients with CC, but that effect may decrease with discontinuation of use. Anorectal physiology testing may be considered in patients on opioids with CC.

469 Efficacy of Biofeedback Therapy for Dyssynergic Constipation Among Elderly Patients

INTRODUCTION: The prevalence of constipation among older adults is estimated to be as high as 40% (Melton et al, 1996). Dyssynergic defecation (DD) is an important cause of constipation for a large proportion of these patients. While biofeedback (BFB) therapy has been shown to be highly effective in correcting DD, it involves operant conditioning which requires learning new techniques and few studies have looked at how older adults respond to BFB. METHODS: This is a retrospective analysis of age 65+ patients enrolled in BFB for DD between 2015 to 2018 at a tertiary referral motility program. For patients that had greater than two sessions, survey and high resolution anorectal manometry (HR-ARM) data were collected at baseline and during each BFB visit. 58 patients met criteria. ARM is utilized with sensors in the rectum and anal canal. Stool retention simulation is performed involving inflation of a rectal balloon during the BFB sessions. RESULTS: Patients described improvement in several meaningful clinical outcomes. The overall median education level was completed high school and some college. Mean global bowel satisfaction on a scale of 1 (very dissatisfied) to 10 (very satisfied) showed a statistically significant increase, 2.77 to 5.01 with BFB (P ≤ 0.0001). In addition, the important symptom of a feeling of incomplete evacuation after stooling decreased from 95% down to 24% (P = 0.0025). Most significantly, 79% of the age 65+ patients showed resolution of their dysyynergia on HR-ARM at their final session (P = 0.0006). The defecation index (DI), intrarectal pressure divided by intra-anal pressure during simulated defecation, also trended towards improvement (0.564 to 0.681, P = 0.12). In terms of types of dyssynergia (1 through 4), subjects with defects in both propulsion and paradoxical contraction of sphincter muscles during defecation, i.e. type 2 dyssynergia, showed the most substantial objective gains in defecation index, with an average increase of 0.486, P-value 0.01 (2 vs 1) and 0.02 (2 vs 3). CONCLUSION: Biofeedback for DD shows meaningful improvement in both patient reported outcomes and objective manometric parameters in older adults. This is an important finding because our data supports the efficacy of BFB among older adults, across all levels of education. Given the profound burden of constipation with DD in older adults, we propose biofeedback therapy continue to be given strong consideration as first line therapy for this population.

Effect of different body position on anorectal manometry for chronic constipation patients.

To analyze the different influence of body position on wireless high-resolution anorectal manometry parameters and in classification for chronic constipation patients. Fifty consecutive patients with chronic constipation and 20 healthy volunteers were included in this study, all of whom accepted the Rome IV constipation questionnaires, underwent rectal balloon expulsion test and wireless high-resolution anorectal manometry. The wireless high-resolution anorectal manometry was performed in the left lateral, seated, and squatting positions for every study subject. The Statistical Product and Service Solutions (SPSS) 21.0 software (IBM Corp., Armonk, NY, USA) was used for statistical analysis. The anal sphincter resting pressure, anal sphincter squeezing pressure, and rectal internal pressure during the evacuation in the seated position and squatting position were significantly higher than those in the left lateral position in both the volunteer group and patient group, without a significant difference between the seated position and squatting position. The initial perception threshold was higher in the patient group than in the volunteer group. The wireless high-resolution anorectal manometry in different positions combined with the rectal balloon expulsion test mainly affects the diagnosis of the subtype of inadequate defecatory propulsion. Compared with the left lateral position test, the wireless high-resolution anorectal manometry in the seated position and squatting positions is more consistent with the human physiological bowel condition, and the result of the test can be affected by the body position. The wireless high-resolution anorectal manometry can differentiate between subtypes during the diagnosis of inadequate defecatory propulsion.

Effect of gender on the etiology of fecal incontinence: Retrospective analysis of a tertiary referral center in Turkey.

Anorectal diseases, including fecal incontinence, are prevalent and have an enormous impact on the quality of life. Therefore, investigating their etiological factors may help to reduce the incidence and/or the severity of the underlying diseases. Referral complaints (constipation, strained defecation, and incontinence) and medical and anorectal manometry records of 883 (562 female/321 male, ages 45.17±1.00 and 48.41±0.63 years, respectively) patients were evaluated retrospectively. Maximal resting pressure (MRP) and maximal squeeze pressure (MSP) measured by stationary pull-through technique, volume of rectoanal inhibitory reflex, and sensory threshold to rectal balloon distention (ST) were obtained by water perfusion system. Data were compared according to referral complaints, age, gender, parity, and underlying diseases. Incontinence was the most frequent referral complaint in 61.2% of females and 67.6% of males. MRP and MSP were significantly lower in incontinent females than in the other groups. In incontinent males, MSP was lower than the strained defecation group, and ST was higher than the constipation group. Age was negatively correlated with MRP for both of the genders and in all groups. Obstetric trauma (85%) and number of parity (3.40±2.59) were significantly higher in incontinent females. Moreover, the most prevalent underlying disease was diabetes in incontinent females (13.7%) and neurological diseases, including traumas, in incontinent males (41.5%). Increasing awareness of labor safety, controlling diabetes mellitus, and preventing obstetric traumas may reduce the prevalence of fecal incontinence.

Reduction in Gastrointestinal Toxicity with Interstitial Hydrogel Spacer during Prostate Proton Therapy

Interstitial hydrogel provides both rectal immobilization and spacing between the prostate and rectum during prostate radiotherapy and reduces the incidence and severity of rectal toxicity. Its use during prostate proton therapy has not yet been evaluated. Patients with localized prostate cancer were treated with definitive proton beam therapy at a single institution on a multi-institutional registry protocol (PCG GU-002). Patients were treated to a dose of 79.2 Gy(RBE) in 44 fractions (762 patients), 70 Gy(RBE) in 28 fractions (102 patients) or 38 Gy(RBE) in 5 fractions (51 patients). Patients were treated in consecutive cohorts with rectal water (RW), rectal balloon (RB) or hydrogel spacer (HS), and followed prospectively for late (>90 days after treatment) adverse events. Toxicity was assessed using CTCAE version 4.0 and compared between cohorts using pairwise chi-square tests. 947 patients treated from 10/10 through 2/17, with median follow-up of 4.4 years and minimum follow-up of 1.5 years. RW was used in 385 patients, RB in 342 patients, and HS in 220 patients. Grade≥3 toxicity did not occur in the HS cohort and was rare in the RW and RB cohorts (<1%). Grade≥2 overall GI toxicity rates were lower for HS (2.2%) relative to RW (14.8%, p<0.001) and RB (17.3%, p<0.001). Grade 2 rectal bleeding was lower for HS (2.2%) relative to RW (10.4%, p<0.001) and RB (12.3%, p<0.001). Interstitial hydrogel spacer during proton therapy reduces the risk of gastrointestinal toxicities and rectal bleeding.

Monitoring Intra-Fraction Prostate Motion Using Kv Triggered Imaging during SBRT

To assess the intra-fraction prostate motion in SBRT treatments using kV triggered imaging of implanted fiducial markers. Seven consecutive patients with prostate cancer underwent SBRT at our institution from Dec 2018 to Feb 2019 were studied. All patients received a total dose of 36.25 or 40 Gy in five fractions with two-arc VMAT using 10 MV FFF beams. All patients had three implanted fiducial markers inside the prostate and one patient (#1) had daily rectal balloon insertion. For each patient, a monitoring structure, “fiducial2mm”, was created by expanding 2 mm of the contoured markers. During treatments, KV triggered images were acquired every 60 degrees of gantry rotation. The centers of the markers were auto detected from the triggered images and compared with the fiducial2mm structure. If any marker center was outside of the fiducial2mm contour, treatment was paused automatically and a new CBCT was required to reposition the patient. Four hundred and sixty kV triggered images were exported for this retrospective analysis. The centers of the markers in the triggered images were detected automatically using an in-house image processing program and compared with the expected marker centers from planning CT. The intra-fraction motion of markers was determined by subtracting the measured marker positions in the triggered images from the expected positions, projected to the patient’s lateral, longitudinal and vertical directions. Fiducial markers were detectable in 450 of the 460 triggered images. Of the seven patients, one (#1) required table position adjustment up to 5 mm during treatment in 3 of the 5 fractions. The remaining six patients had no beam interruption or table position correction during treatments. On average, the intra-fraction motion of prostate, measured by fiducial markers was 2.0 mm. The prostate tended to move inferiorly (p<0.001). Intra-fraction motion was not correlated with treatment time. The motion measured from images taken within 5 minutes from CBCT was not statistically different from the images taken after 5 minutes from CBCT. KV triggered imaging is a useful tool to monitor the intra-fraction prostate motion for patients receiving SBRT. The average intra-fraction prostate motion was 2 mm in 3-D vector. With 2 mm intra-fraction margin, most patients do not have treatment interruption when monitored by triggered imaging.Abstract 3748; Table 1Patient# 1 (w rectal balloon)# 2# 3# 4# 5# 6# 7# of triggered images70626368596068Intra fraction motion [mm]w/o table correctionw table correctionNo table correctionLat (left+, right-)0.1 +/- 1.20.0 +/- 0.8-0.1 +/- 1.00.2 +/- 1.0-0.3 +/- 0.8-0.2 +/- 0.90.4 +/- 0.8-0.3 +/- 0.9Long (sup+, inf-)-2.3 +/- 2.8-0.3 +/- 1.4-0.4 +/- 1.20.2 +/- 1.5-0.8 +/- 1.0-0.6 +/- 1.4-0.9 +/- 1.2-1.6 +/- 0.9Vrt (ant-,post+)0.2 +/- 2.30.7 +/- 1.6-1.0 +/- 1.10.3 +/- 1.40.2 +/- 1.10.9 +/- 1.20.7 +/- 0.90.5 +/- 1.13D vector3.7 +/- 2.52.0 +/- 1.32.0 +/- 0.92.1 +/- 1.01.7 +/- 0.91.8 +/- 1.51.9 +/-1.82.1 +/- 1.0 Open table in a new tab

Are there sex differences in visceral sensitivity in young healthy men and women?

Visceral hypersensitivity plays a key role in the pathophysiology of chronic visceral pain like irritable bowel syndrome (IBS), which is significantly more prevalent in women. Possible sex differences in visceral sensitivity remain poorly studied. We assessed sex differences in visceral sensitivity and their association with subclinical symptoms, trait anxiety, and chronic stress in a large sample of healthy men and women. In 280 young healthy volunteers (50% female), visceral sensory and pain thresholds were determined using rectal balloon distensions. Gastrointestinal (GI) symptoms, chronic stress, and trait anxiety as IBS-related risk factors were assessed with questionnaires. Men and women were compared regarding visceral sensitivity and multiple regression analyses were conducted to evaluate the predictive value of sex and risk factors for visceral sensitivity. Subgroups with high, intermediate, and low sensitivity were compared regarding psychological and biological characteristics. Men and women did not differ in sensory or pain thresholds or in IBS-related risk factors. In multiple regression analyses, no predictor of visceral sensitivity could be identified. While sensitivity subgroups differed in sensory and pain thresholds, the proportions of men and women were comparable, and groups did not differ in IBS-related risk factors. Despite the large sample size, we found no evidence supporting sex differences in visceral sensitivity. At least in healthy young volunteers, our findings suggest that sex, GI symptoms, anxiety, or chronic stress do not contribute to altered visceral sensitivity.

Visceral sensitivity remains stable over time in patients with irritable bowel syndrome, but with individual fluctuations.

Visceral hypersensitivity in irritable bowel syndrome (IBS), measured with rectal balloon distensions, using a barostat, has been suggested to be a phenomenon that is reduced due to habituation at repeated investigations. We investigated the stability of rectal sensitivity in patients with IBS who had undergone a previous rectal barostat study and assessed variations in symptom pattern and severity in relation to rectal sensory function. Irritable bowel syndrome patients, who had previously been undergone a rectal barostat study, were included. All patients underwent a second study 8-12years later. Symptoms were characterized by use of questionnaires. We included 26 subjects (17 females, median age at the index investigation 44.5 (21-61) years). Pressure and volume sensory thresholds were unchanged at the follow-up compared with the index investigation (P>0.05 for all). At the index investigation, 8/26 patients had rectal hypersensitivity of which four were reclassified as normosensitive, and sixfrom normo- to hypersensitive, meaning that 10/26 patients were hypersensitive at the follow-up investigation. IBS-QOL had improved significantly in six of nine domainsat follow-up (P<0.05 for all). There were no differences in anxiety, depression, IBS symptom severity, or somatization (P>0.05) at follow-up. None of these were associated with change in rectal sensitivity at follow-up. Rectal hypersensitivity and IBS symptoms remained stable at the group level over 8-12years in IBS patients, even though individual fluctuations were noted. Our findings contradict previous findings indicating that visceral hypersensitivity is an unstable trait.

Evidence for an association of gut microbial Clostridia with brain functional connectivity and gastrointestinal sensorimotor function in patients with irritable bowel syndrome, based on tripartite network analysis

Background and aimsEvidence from preclinical and clinical studies suggests that interactions among the brain, gut, and microbiota may affect the pathophysiology of irritable bowel syndrome (IBS). As disruptions in central and peripheral serotonergic signaling pathways have been found in patients with IBS, we explored the hypothesis that the abundance of serotonin-modulating microbes of the order Clostridiales is associated with functional connectivity of somatosensory brain regions and gastrointestinal (GI) sensorimotor function.MethodsWe performed a prospective study of 65 patients with IBS and 21 healthy individuals (controls) recruited from 2011 through 2013 at a secondary/tertiary care outpatient clinic in Sweden. Study participants underwent functional brain imaging, rectal balloon distension, a nutrient and lactulose challenge test, and assessment of oroanal transit time within a month. They also submitted stool samples, which were analyzed by 16S ribosomal RNA gene sequencing. A tripartite network analysis based on graph theory was used to investigate the interactions among bacteria in the order Clostridiales, connectivity of brain regions in the somatosensory network, and GI sensorimotor function.ResultsWe found associations between GI sensorimotor function and gut microbes in stool samples from controls, but not in samples from IBS patients. The largest differences between controls and patients with IBS were observed in the Lachnospiraceae incertae sedis, Clostridium XIVa, and Coprococcus subnetworks. We found connectivity of subcortical (thalamus, caudate, and putamen) and cortical (primary and secondary somatosensory cortices) regions to be involved in mediating interactions among these networks.ConclusionsIn a comparison of patients with IBS and controls, we observed disruptions in the interactions between the brain, gut, and gut microbial metabolites in patients with IBS—these involve mainly subcortical but also cortical regions of brain. These disruptions may contribute to altered perception of pain in patients with IBS and may be mediated by microbial modulation of the gut serotonergic system.

Application of Rectal Prolapse Constipation Balloon in Single Auxiliary Defecation

To explore the application value of rectal prolapse constipation balloon in single auxiliary defecation. Forty-one patients with moderate or severe rectocele were treated with a rectocele constipation balloon through the vagina. The defecography and VAS scores were compared before and after implantation. There was a significant difference between the anorectal angle, rectocele, and VAS scores before and after intervention in defecography (P<0.01). A single assisted defecation of the rectocelicular constipation balloon is feasible.

Heterogeneous Dose-Escalated Prostate Stereotactic Body Radiation Therapy for All Risk Prostate Cancer: Quality of Life and Clinical Outcomes of an Institutional Phase 2 Study

Most published prostate SBRT studies treated low to intermediate-risk prostate cancer (CaP) with uniform doses of 35-40 Gy/ 5 fx. Previous attempts at uniform dose escalation to 50 Gy caused high rates of GI toxicity. We hypothesized heterogeneous dose escalation to 50 Gy to regions of the prostate not adjacent to the urethra, rectum and bladder is safe and efficacious. We report outcomes of an institutional phase II protocol. Thirty-five patients were enrolled on an institutional review board approved phase II study. Treatment involved LINAC based VMAT or IMRT with a rectal balloon. The contoured prostate was expanded by 3 mm (0 mm posteriorly). A prescription target of 50 Gy/ 5 fx was delivered to >50% of the portion of PTV >3 mm from sensitive structures (urethra, rectum, bladder), while the seminal vesicles and PTV <3mm from sensitive structures were treated to 36.25 Gy/ 5 fx. Study patients completed the EPIC-26 questionnaire at baseline and 1.5, 4, 8 and 12 months post SBRT. Clinically significant changes in quality of life (QOL) over time were determined using a minimally clinically important difference (MCID), defined as a change of >1/2 the standard deviation of the baseline QOL value. One patient had low, 12 intermediate (4 with multiple risk factors), and 16 high-risk CaP. Median and mean iPSAs were 9.0 and 16.6 ng/ml. Androgen deprivation therapy (median 6 months) was given to 17 patients (59%). Median age was 70 yrs. At median follow-up of 46 months, treatment was well-tolerated. Urinary irritation/obstructive and urinary bother scores declined by MCID threshold from baseline assessment to the first visit at six weeks post SBRT, but subsequently recovered by 4 months. No differences were observed for urinary incontinence, bowel domain, bloody stools, or sexual domain. One patient developed acute grade 2 GU toxicity and 2 patients developed acute grade 2 or higher GI toxicity. One patient developed late grade 2 GU toxicity and 4 patients developed late grade 2 or higher GI toxicity. This includes one patient with a very large prostate (270 cc) and implanted radiofrequency transponders who developed prostatic infection 3 weeks post SBRT, requiring surgical debridement resulting in acute and late grade 4 GI toxicities. Freedom from biochemical failure (nadir +2) at 3 years was 88.9%. Heterogeneous dose-escalated prostate SBRT was well-tolerated in patients with predominantly intermediate and high-risk CaP, with the exception of a single high grade toxicity of likely of infectious etiology. Urinary irritation/obstructive scores and urinary bother scores declined from baseline to six weeks post SBRT, but recovered by fourth months. There was no change in bloody stools or bowel domain scores with SBRT. Further investigation and follow-up is needed to establish the role of heterogeneous dose-escalated SBRT in CaP.

Late Rectal Bleeding in Patients with and Without Pre-Rectal Hydrogel Spacer During Proton Beam Therapy for Prostate Cancer

Rectal toxicity is a potential late complication of radiation therapy for localized prostate cancer. A randomized trial in patients treated with IMRT supported the use of a bio-absorbable hydrogel spacer, inserted between the rectum and prostate, to reduce rectal toxicity. Proton beam therapy (PBT) improves low to moderate dose rectal dosimetry parameters and decreases integral dose compared to IMRT; however, rectal toxicity can still occur given the proximity the prostate to the anterior rectal wall. The benefit of a hydrogel rectal spacer for patients undergoing PBT has not been well studied. We examined the dosimetric impact of rectal spacer and late rectal bleeding rates in patients undergoing PBT. Patients with localized, clinical stage T1-2 prostate adenocarcinoma were treated at a single institution using conventionally fractionated PBT (typically 79.2 CGE in 44 fractions) from 2013 to 2017. Baseline clinical parameters were collected prospectively in an institutional review board-approved registry. Intraprostatic fiducial placement for daily image-guided RT. A subset of patients also had a commercially available hydrogel spacer transperineally inserted in the pre-rectal space at the time of fiducial placement. Daily immobilization with rectal balloon was used in patients who did not undergo spacer placement. Late GI toxicity (after 6 months), including rectal bleeding (RB), was graded using CTCAE v4.0. A total of 192 patients were treated with PBT without spacer and 82 were treated with spacer. Overall, 17%, 58%, and 24% of patients had low, intermediate, and high-risk disease, respectively. Most patients had radiation to the prostate and seminal vesicles only (91%), while 9% had elective nodal coverage. There were no differences between the two groups with regards to age, risk group, aspirin/anticoagulation use, and baseline GI comorbidities (IBD, hemorrhoids, fissures, hypertension). The mean PTV D95% was 79.1 CGE and 78.8 CGE in the non-spacer and spacer cohort, respectively (p=0.23). Use of hydrogel spacer significantly reduced the volume of rectal wall treated in the 50-81 Gy dose range (table). In the entire cohort, RB was associated with a history of smoking, anti-coagulation use, and hypertension. In patients with at least 6 months follow up, median follow up was 18 and 11 months in the non-spacer and spacer groups, respectively. Between the non-spacer and spacer groups, there was a reduction in the 1-year rates of any RB (13.5% vs 6.8%) and Grade 2 or worst RB (6.2% vs 2.3%), but this did not reach statistical significance (log-rank p=0.22 and p=0.50). Insertion of a hydrogel spacer in patients undergoing PBT for prostate cancer improves rectal wall dosimetry and may decrease the rate of late rectal bleeding. Further follow-up is awaited to see if this difference is statistically significant.Abstract SU_26_2253; Table 1Rectal Wall Vx (Gy)No Spacer (%)Spacer (%)P-valueV5030.021.5<0.001V6523.111.3<0.001V7020.27.4<0.001V7516.33.6<0.001V81 (cc)0.2 cc0 cc<0.001 Open table in a new tab

The Rao Protocol for Anal Incontinence Improves Key Patient Reported Outcomes as Well as Objective Endurance on High Resolution Anorectal Manometry

Introduction: In the United States, over 8% of adults are affected by anal incontinence (AI). When therapy mainstays such fiber supplements and anti-diarrheal medications fall short for patients, biofeedback (BFB) therapy is a key intervention, although a universal protocol has not been established. The Rao protocol for BFB is a physician-led program that consists of an active phase tailored to each patient, focusing on increasing sphincter tone and endurance, followed by refresher sessions. A solid state manometry catheter is utilized with sensors in the rectum and anal canal (instead of digital, EMG or ultrasoundbased approaches). Biofeedback is performed with a rectal balloon that can be inflated to simulate stool. Methods: This is a retrospective analysis of patients enrolled in BFB for AI between 2015 to 2018 at a tertiary referral motility program. For patients that had greater than two sessions, survey and high resolution anorectal manometry (HR-ARM) data were collected at baseline and during each AI BFB visit. 36 patients met criteria whose clinical characteristics are presented in table 1. Results: Self-reported mean global stool satisfaction on a scale of 1 (very dissatisfied) to 10 (very satisfied) showed a statistically significant increase from 3.6±2.6 at the start to 5.5±2.6 (p=0.0032) by the final visit. The mean number of AI accidents in one week was significantly reduced from 6±11 to 2±4 (p=0.0497). There were notable reductions in the number of patients using pads, stooling medications, and reporting urge AI symptoms by 20%, 32% and 19%, respectively. HR-ARM features were measured during each session and there was an improvement in endurance, defined as length of time able to maintain 50% of max squeeze pressure. With rectal balloon inflated to simulate stool, mean time (seconds) improved from 22 at session one to 24, and 29 by session three (p=0.0387). Contractile index, an integration of average squeeze over the first 10 seconds, was calculated for each BFB visit but did not show statistically significant change. Conclusion: Biofeedback with the Rao protocol in conjunction with use of HR-ARM catheters shows durable improvement in both meaningful clinical outcomes and objective endurance. The manometric data suggest gains in endurance may be predominantly responsible for the clinical benefits. We propose that the Rao protocol’s endurance training be given important consideration in BFB therapy for AI.425 Figure 1 No Caption available.

Characterization of Simultaneous Pressure Waves as Biomarkers for Colonic Motility Assessed by High-Resolution Colonic Manometry.

Simultaneous pressure waves (SPWs) in manometry recordings of the human colon have been associated with gas expulsion. Our hypothesis was that the SPW might be a critical component of most colonic motor functions, and hence might act as a biomarker for healthy colon motility. To that end, we performed high-resolution colonic manometry (HRCM), for the first time using an 84-sensor (1 cm spaced) water-perfused catheter, in 17 healthy volunteers. Intraluminal pressure patterns were recorded during baseline, proximal and rectal balloon distention, after a meal and following proximal and rectal luminal bisacodyl administration. Quantification was performed using software, based on Image J, developed during this study. Gas expulsion was always associated with SPWs, furthermore, SPWs were associated with water or balloon expulsion. SPWs were prominently emerging at the termination of proximal high amplitude propagating pressure waves (HAPWs); we termed this motor pattern HAPW-SPWs; hence, SPWs were often not a pan-colonic event. SPWs and HAPW-SPWs were observed at baseline with SPW amplitudes of 12.0 ± 8.5 mmHg and 20.2 ± 7.2 mmHg respectively. The SPW occurrence and amplitude significantly increased in response to meal, balloon distention and luminal bisacodyl, associated with 50.3% anal sphincter relaxation at baseline, which significantly increased to 59.0% after a meal, and 69.1% after bisacodyl. Often, full relaxation was achieved. The SPWs associated with gas expulsion had a significantly higher amplitude compared to SPWs without gas expulsion. SPWs could be seen to consist of clusters of high frequency pressure waves, likely associated with a cluster of fast propagating, circular muscle contractions. SPWs were occasionally observed in a highly rhythmic pattern at 1.8 ± 1.2 cycles/min. Unlike HAPWs, the SPWs did not obliterate haustral boundaries thereby explaining how gas can be expelled while solid content can remain restrained by the haustral boundaries. In conclusion, the SPW may become a biomarker for normal gas transit, the gastrocolonic reflex and extrinsic neural reflexes. The SPW assessment reveals coordination of activities in the colon, rectum and anal sphincters. SPWs may become of diagnostic value in patients with colonic dysmotility.