SNS was performed by the standard 2-stage technique (temporary then permanent implanta-tion). During a 4 week period of temporary stimulation, patients were randomized ON-OFF/OFF-ON for two 2-week periods. Prior to insertion (PRE), and during each crossoverperiod, outcome variables (bowel diaries, constipation and GIQoL scores) were assessed,and rectal sensory thresholds determined. Results: All thirteen patients completed the trialwithout complication. Following stimulation, there was a significant increase in percentageof successful bowel movements (PRE: median 34% [0-100] vs ON: 74% [20-100] vs OFF:72% [0-100]; P=0.007), and Wexner constipation scores improved in 11/13 patients, (PRE:median 18 [9-26] vs ON: 12 [6-27] vs OFF: 13 [5-29]; P=0.01). Defaecatory desire volume(DDV) to rectal balloon distension were normalized in 11/13 patients (PRE: median 277ml [120-380] vs ON: 163 ml [90-260] vs OFF: 220 ml [80-340 ml]; P=0.006) and maximumtolerable volume (MTV) in 11/13 (PRE: median 350 ml [270-420] vs ON: 262 ml [100-400] vs OFF: 298 ml [120-410 ml]; P=0.01). There were no significant changes in healthrelated quality of life measures (GIQoL, Sf36). Conclusion: Patients with constipation second-ary to rectal evacuatory dysfunction with rectal hyposensitivity appear to benefit from SNS,at least in the short-term. The physiological results presented support a mechanistic rolefor rectal afferent modulation.

Mo1313

The Number of Retained Rectosigmoid Markers During Colonic TransitTesting Does Not Reliably Predict the Presence of Dyssynergic DefecationMonthira Maneerattanaporn, Jason Baker, William D. Chey

Background/Aims: Subgroups of chronic constipation (CC) include patients with slow transitand/or dyssynergic defecation. Radiopaque markers tests (ROMs) have been used to identifyslow transit CC while anorectal manometry (ARM) & the balloon expulsion test (BET) havebeen used to diagnose dyssynergic defecation (DD). It has been suggested that the retentionof markers in the rectosigmoid on ROM testing identifies patients who are more likely tohave DD. We tested this hypothesis in a cohort of CC patients who had undergone evaluationwith ROM, ARM, and BET. Methods: This was a retrospective cohort study in patientsreferred to a tertiary center who had undergone testing with ROM, ARM and BET forpersistent CC symptoms. ROM testing was performed using the Metcalf method. DD wasdefined by an abnormal ARM (paradoxical anal sphincter contraction during simulateddefecation) or BET (inability to pass a 50 cc water-filled rectal balloon within 60 seconds).Plain films from the ROM study were reviewed and the number of retained rectosigmoidmarkers on Day 4 (D4), Day 7 (D7), and combined (D4+D7) were tabulated. A logisticregression model was created to identify any relationship between the number of retainedrectosigmoid markers and DD. A P-value of <0.05 with OR > 1 were selected to identifythe level of statistical significance. Results: 127 CC pts (F=117, mean age=43.9 (17-80) yrs)were included. 71/127 (56%) had an abnormal ARM or BET and were diagnosed with DD.There were no significant differences in the proportion of patients with slow transit by ROMtesting in those with and without DD (54% vs. 36%, p>0.05). No significant differenceswere found in the number of retained rectosigmoid markers on D4, D7, or combined inpatients with and without DD (table). Of patients with DD, 78% & 79% had fewer than10 rectosigmoid markers on D4 or D7. In a subgroup analysis, only patients with >25retained rectosigmoid markers on D4, D7, or combined were considered. Logistic regressionanalysis demonstrated that retention of the larger number of rectosigmoid markers was alsonot predictive of DD on D4 (P=0.62, OR=0.99[0.96, 1.03]), D7 (P=0.38, OR=1.02[0.98,1.07]), or the sum from D4+D7 (P=0.53, OR=1.01[0.98, 1.03]). Conclusion: Contrary toconventional teaching, we found no difference in the number of retained rectosigmoidmarkers on ROM testing in chronic constipation patients with and without dyssynergicdefecation. ROM testing cannot be reliably used to identify patients in need of an evaluationfor dyssynergic defecation.

Mo1314

Prospective Comparison of Balloon Expulsion, Anorectal Manometry andEvacuation Proctography for the Diagnosis of Rectal Evacuatory DisorderSomnath Palit, Noel N. Thin, Charles H. Knowles, S. Mark Scott

INTRODUCTION: Evacuatory dysfunction can occur due to functional (dyssynergic defaec-ation) or mechanical obstruction (e.g. resulting from anatomical abnormalities such as rectalintussusception, rectocoele etc.). Unfortunately, there is lack of a gold standard investigation;tests are poorly standardized and very few studies have prospectively compared them. Theaim of this study was to compare the three most widely available tests in clinical practice:anorectal manometry (ARM), balloon expulsion test (BET) and evacuation proctography(EP). METHODS: 26 adults (6 M) with chronic constipation referred for anorectal physiologytesting underwent ARM, BET and EP. For ARM, an intrarectal pressure <45 mmHg, or acontraction or failure to relax the anal sphincters during simulated defaecation were consid-ered abnormal. BET was performed in the sitting position, first with a water-filled 50 mlballoon (BET50), and again with a volume that generated a desire to defaecate (BETDDV).Failure to expel the balloon in 60 secs (male) or 90 secs (female) was considered abnormal.EP was performed with barium-oats-water mixture using a volume sufficient to produce astrong desire to defaecate. Impaired evacuation, secondary to poor anal or pelvic floorrelaxation and/or persistent puborectalis impression constituted a functional obstruction.

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Anatomical abnormalities seen during EP were recorded, and also whether they caused amechanical impairment to defaecation. RESULTS: For diagnosis of impaired evacuation,there was substantial agreement between both BET50 and BETDDV and EP (85%, Kappavalue = 0.62, and 89%, Kappa value = 0.65, respectively). An excellent agreement (88%,Kappa value = 0.72) was present between the two balloon expulsion tests. Of the 4 patientswith impaired evacuation on both BET and EP, all 4 had a dyssynergia on ARM. However,manometry alone greatly over-diagnosed dyssynergic defaecation, with 10 out of 19 patientswith normal evacuation parameters on both EP and BET meeting the criteria for dyssynergia.13 of 17 patients with normal expulsion on both BET tests were found to have mechanicalabnormalities on EP. CONCLUSIONS: There is a substantial agreement between balloonexpulsion test and evacuation proctography for identifying dyssynergic defaecation. Proctog-raphy provides morphological information that may account for symptoms of obstructeddefaecation, even when global measures of evacuation are normal. Anorectal manometrygreatly over-diagnoses dyssynergia.

Mo1315

A Randomised, Placebo Controlled, Double Blind Study to Assess the Efficacyof a Probiotic Dairy Product Containing Lactobacillus Casei Shirota onSymptoms in Irritable Bowel SyndromeAnnemieke Yvonne Thijssen, Daisy Jonkers, Vanessa Vankerckhoven, Herman Goossens,Bjorn Winkens, Cees H. Clemens, Ad Masclee

Introduction: Alterations in the gut microbiota composition have been described in IBSpatients and are proposed as one of various pathophysiological mechanism in IBS, whichcan potentially be influenced by probiotic treatment. Several studies with probiotics in IBShave pointed to beneficial results with improvement of IBS symptoms. Aim of the presentstudy was to assess in a randomised placebo controlled double blind trial the effect of aprobiotic product containing Lactobacillus casei Shirota on symptoms in patients with IBS.Materials and methods: IBS patients between 18 and 65 years of age, fulfilling the Rome IIcriteria, were included. Probiotic and placebo product were provided by Yakult Europe,Almere, NL. Patients had to take 2 bottles daily for 8 weeks, containing at least 6.5 x 109CFU living Lactobacillus casei Shirota (LcS) per bottle. All subjects completed a dailysymptom diary (ranging from no to very severe symptoms) during 3 periods of 2 weeks:before intervention (week -2/0), at the end of intervention (week 6/8) and during follow-up (week 14/16). Mean symptom scores (MSS) were based on discomfort, pain, constipation,diarrhoea and bloating. Results: 39 patients (26F; 41 ± 15 yrs) in the probiotic group and41 patients (29F; 42 ± 14 yrs) in the placebo group were included. The compliance was >95% in both groups (LcS in stool, bottles used). Demographic data did not differ betweengroups. An improvement in symptoms of > 30% was predefined as clinically relevant. Afterfollow-up, an improvement > 30% was reached for all symptoms, apart from bloating, inthe probiotic group, but for none of the symptoms in the placebo group. The improvementwas significantly higher in the probiotic group compared to the placebo group for discomfort(34 ± 7%; 12 ± 9%), flatulence (33 ± 7%; 7 ± 10%) and total symptom score (33 ± 7%;10 ± 9%) (all p ≤ 0.05), and showed a non significant improvement for pain (33 ± 12%;-17 ± 25%, p = 0.10) and MSS (34 ± 7%; 13 ± 8%, p = 0.06). Logistic regression showeda possible interaction with gender for the treatment given. In males (13 probiotics / 12placebo), probiotic treatment resulted in a significantly higher improvement in each symptomscore compared to placebo treatment (all p < 0.05). In females (26 probiotics / 29 placebo)treatment did not influence any symptoms (all p > 0.10). Conclusions: Intervention withLactobacillus casei Shirota resulted in a significantly higher percentage of patients withimprovement of symptoms in the probiotic compared to the placebo group. This significantbenefit was observed in males but not in females.

Mo1316

A Single Administration of Pregabalin Modifies Colonic Sensation and MotorFunction in Healthy Adults: Proof of Concept of the Potential Application ofPregabalin in Irritable Bowel SyndromeJohanna Iturrino, Irene A. Busciglio, Duane D. Burton, Alan R. Zinsmeister, MichaelCamilleri

Background: Pregabalin is an α2δ ligand that is used clinically to treat somatic and abdominalpain. A prior study of rectal sensorimotor function using the barostat and dose-escalationin patients with irritable bowel syndrome (IBS) suggested pregabalin reduces rectal painwhile increasing compliance (Houghton et al. Gut 2007;56:1218-25). Our aims were to:(1) quantify the effect of pregabalin on colonic sensory and motor functions; (2) assess therelationship between analgesic effects and its compliance in healthy subjects. Methods: Weconducted a randomized, double-blind, placebo-controlled, parallel-group study of a singleoral administration of 75 or 200mg pregabalin in 60 healthy adults between the ages of 18and 75y. After standardized bowel preparation and fasting overnight, subjects underwent leftcolon intubation with unsedated flexible sigmoidoscopy. We assessed compliance, sensationthresholds, sensation ratings over 4 levels of distension (16, 24, 30, 36mmHg above baselineoperating pressure), fasting and postprandial (1000kcal liquidmeal) colonic tone andmotilityindex (MI, phasic pressure activity). Colonic compliance was determined as the volumeresponse to 4 mmHg pressure increments over 0 to 60mmHg. Pressures corresponding to10 and 50% of Volmax were used as compliance measures. ANCOVA (adjusted for age,gender, BMI and corresponding pre-drug response) and Proportional Hazards models wereused in an interim analysis with 70% of study completed and analyzed. Results: Therewere no clinically important differences among treatment groups for demographics, predrugcompliance, tone,MI and sensation. Pregabalin did not significantly affect colonic compliance,sensation thresholds, colonic fasting tone and MI. However, overall treatment effects (seetable) were numerically different (p=0.055) for postprandial tone and sensation ratings forgas (p=0.08) and pain (p=0.07) averaged over the 4 distension levels (but not the highestdistension analyzed alone). The table shows differences were attributable to pregabalin200mg dose, not the 75mg dose. Conclusion: Single administration of 200mg pregabalinappears to reduce colonic sensation ratings for gas and pain without altering colonic compli-ance, suggesting reduction in afferent function. Pregabalin 200mg may also increase colonictone in response to a meal. These effects suggest that pregabalin has the potential to decrease

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