Oral (pre-recorded) Biliary    OB03 Biliary: Gallstones  Selection of Presentations from Abstract Submissions OB03-02  Sphincter of Oddi Laxity Alters Bile Duct Microbiota and Contributes to the Recurrence of Chelodocholithiasis Qi Zhang, China Q. Zhang1, M. Ye1, X. Bai2, T. Liang2 1HBP Department, Zhejiang University, School of Medicine, the First Affiliated Hospital, China, 2Zhejiang University, School of Medicine, the First Affiliated Hospital, China Background: Chelodocholithiasis is closely associated with bacterial infection and inflammation in the bile ducts. Our previous studies showed that sphincter of Oddi laxity (SOL) significantly altered the bile microbiota and might contribute to biliary stone recurrence. However, the direct association among SOL, bile microbiota, and chelodocholithiasis recurrence has not been well investigated. Methods: We recruited 202 patients with chelodocholithiasis, and obtained the bile samples from the common bile duct. We performed 16S rRNA gene analysis to characterize the bile microbiota, and analyzed the risk factors of chelodocholithiasis. Results: Distinct bile microbial communities were identified in patients with and without SOL with a significantly greater abundance of Rhizobiaceae in SOL patients. SOL patients had a higher risk of biliary stone recurrence with a considerably shorter recurrence time. The abundance of Clostridium was significantly higher in recurrent patients. SOL (P = 0.045, HR = 8.563) and pre-operative gamma-glutamyl transferase level (P = 0.037, HR = 1.002) were two independent risk factors of chelodocholithiasis recurrence. Conclusions: Chelodocholithiasis patients with and without SOL demonstrated significant differences in their microbial communities. SOL is a critical risk factor of chelodocholithiasis recurrence after surgery. The presence of Clostridium is potentially associated with SOL-induced chelodocholithiasis recurrence. OB03-03  Natural History of Retained Common Bile Duct Calculi Noted on Intra-Operative Cholangiography Andy Chen, Australia A. Chen1, R. Tang2, P. Garg1, V. Lam1, T. Pang1 1Department of Surgery, Westmead Hospital, Australia, 2Department of Radiology, Westmead Hospital, Australia Introduction: Incidental common bile duct (CBD) calculi is found in approximately 11% of routine intra-operative cholangiograms (IOC) during laparoscopic cholecystectomy (LC). An uncertain proportion of these may remain asymptomatic or pass spontaneously, and therefore not require invasive intervention. We aim to explore the natural history of retained CBD calculi in asymptomatic patients to guide management for this common incidental operative finding. Methods: Retrospective analysis of LC performed at an Australian tertiary hospital from 2014 to 2018 was undertaken. Records of patients with filling defects noted on IOC were reviewed. Incidental patients were defined by preoperative bilirubin< 40µmol/L and gamma-glutamyl transferase< 500U/L. The main endpoint was the passage of CBD calculus, determined by the absence of choledocholithiasis on postoperative magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP). Results: 1453(87%) patients underwent IOC with LC and filling defects were noted in 116(8%) of these. 75 incidental patients underwent postoperative cholangiography within 30 days at a median of 3(IQR=2-6) days following LC. 32(43%) patients had no residual choledocholithiasis. The median time to stone passage was estimated at 10(95%CI 5.6-14.3) days. Retained choledocholithiasis was detected in 72% of patients where no contrast passed into the duodenum and 48% with duodenal contrast passage but filling defects on IOC (p=0.049). Conclusion: A significant proportion of incidental CBD calculi pass spontaneously within 14 days from LC. Expectant management with follow-up non-invasive imaging may reduce unnecessary ERCP and minimise its associated complications. However, failure of contrast passage into the duodenum on IOC may predict non-passage of choledocholithiasis. OB03-04  The Prevalence of Functional Gastrointestinal Disorders in Patients with Uncomplicated Cholecystolithiasis (PERFECT): a Prospective, Multicenter Observational Study Carmen Sarah Sophie Latenstein, Netherlands C.S.S. Latenstein1, J. de Jong2, D. Boerma3, E. Hazebroek4, J. Heikens5, J. Konsten6, F. Polat7, J. Drenth2, P. de Reuver1 1Surgery, Radboudumc, Netherlands, 2Gastroenterology and Hepatology, Radboudumc, Netherlands, 3Surgery, Antonius Ziekenhuis Nieuwegein, Netherlands, 4Surgery, Rijnstate, Netherlands, 5Surgery, Ziekenhuis Rivierenland, Netherlands, 6Surgery, Viecuri, Netherlands, 7Surgery, Canisius Wilhelmina Ziekenhuis, Netherlands Background: Symptomatic gallstones, functional dyspepsia(FD), and irritable bowel syndrome(IBS) have similar symptom pattern. This study determined the prevalence of FD/IBS in patients with gallstones and assessed the outcome of a cholecystectomy in terms of resolution of biliary colics and abdominal pain. Methods: A multicentre, prospective observational study was conducted. Adult patients with abdominal pain and ultrasonically confirmed gallstones were included. The presence of FD/IBS was assessed with the validated ROME-IV questionnaire. A biliary colic was defined by the ROME-III criteria. Pain-free was defined as an Izbicki Pain Score ≤10. Patients with and without FD/IBS at baseline were compared. Results: Between January 2018-April 2019, 401 patients (51.7 years, 76.3% females) were included. In total, 34.9% (140/401) of the patients with gallstones fulfilled the ROME-IV criteria for FD/IBS, and 64.1% (257/401) fulfilled the ROME-III criteria for biliary colic. Cholecystectomy rate was similar between the groups (73.8% in FD/IBS-group vs. 75.5% in patients without FD/IBS, p=0.720). After follow-up of 24 weeks the biliary colic was resolved in 93.9% of patients with surgery (91.4% in FD/IBS-group vs. 95.1% in patients without FD/IBS, p=0.220). Pain-free after surgery was achieved in 56.8% of patients (40.7% in FD/IBS-group vs. 64.4% in patients without FD/IBS, p< 0.001). Conclusion: One-third of the patients with gallstones fulfil criteria for FD and/or IBS. Cholecystectomy resolves biliary colics in 94% of patients, with similar outcome between patients with and without FD/IBS. However, pain-free after surgery is significantly less in patients with FD/IBS. This study partially explains the poor pain reduction after cholecystectomy. OB03-05  Should Common Bile Duct Exploration Be a Specialist Only Procedure? a 10 Year Review of 551 Consecutive Patients Russell Hodgson, Australia R. Hodgson1,2, D. Heathcock1, C.-T. Kao1, R. Seagar1, M. Tacey1,2, T. Yong1, D. Bird1, N. Houli1,3 1Surgery, Northern Health, Australia, 2Surgery, University of Melbourne, Australia, 3Western Health, Australia Introduction: Common bile duct (CBD) exploration is not commonly performed, despite evidence that it may be superior to ERCP in the treatment of choledocholithiasis. Issues surrounding its uptake in the laparoscopic era include perceived difficulty and lack of training. We aim to determine whether CBD exploration should be performed by 'specialist' CBD surgeons. Methods: A 10-year retrospective audit was performed of patients undergoing CBD exploration for choledocholithiasis at Northern Health, Australia. CBD exploration was performed almost exclusively using choledochoscopy. Northern Health maintains an on-call available 'specialist' CBD surgeon should the operating surgeon choose to utilise their service. Results: 551 patients were identified, of which 489/551 (88.7%) patients had stones successfully cleared. 413 (75.0%) of operations were done by a 'specialist'. Specialists had a higher success rate (90.8% vs 82.6%), possibly as they were more persistent with a longer surgical time (186 min vs 161 min). Method (transcystic or transductal), approach (laparoscopic or open), pre-operative markers, and indication for operation were not different between groups. In addition, there was no significant difference in complication rates. When caseload was evaluated, to be confident of a surgeon having a minimum 80% success rate, approximately 70 procedures over 10 years were required. Discussion: Specialist CBD exploration surgeons have improved success rates compared with non-specialist general surgeons. However non-specialist general surgeons also have a high success rate and, with similar complication rates and to avoid a high learning curve requirement, they should be encouraged to perform CBD exploration in centres without specialist CBD exploration support. OB03-06  Long Term Outcomes of Trans-Cystic Bile Duct Exploration Joel Lewin, Australia C. O'Rourke, J. Lewin, P. Waters, L. Weber, D. Cavallucci, R. Bryant, N. O'Rourke Royal Brisbane Hospital, Australia Introduction: Laparoscopic transcystic common bile duct exploration (LTCBDE) at the time of cholecystectomy for choledocholithasis negates the need for endoscopic retrograde cholangiopancreatography (ERCP), along with its associated complications and cost. The aim of this study was to assess the long-term outcomes associated with TCBDE. Methods: Patients undergoing LTCBDE at the Royal Brisbane Hospital between 1995 and 2019 were retrospectively analysed. LTCBDE was performed using a 5.5-Fr wire basket kit (Cook Australia) under fluoroscopic guidance. Satisfactory completion of the CBD exploration was confirmed by completion cholangiography. Patients had clinical follow up post discharge. Data were analysed using R statistics with a p< 0.05 considered significant. Results: 397 patients underwent LTCBDE, with 262 females. The median age was 52 years old (range 16-88). Median follow up was 5.4 years, and the median length of hospital stay was 1 day (range 0 - 28). 28 patients (7.1%) required postoperative ERCP for failure of complete stone clearance at LTCBDE. Two patients developed mild acute pancreatitis postoperatively after successful duct clearance. Four patients (1%) required ERCP following discharge post LTCBDE, after representing with symptomatic choledocholithiasis. Overall, 91.9% of patients had successful bile duct clearance with LTCBDE. Cost analysis comparing LTCBDE with the average cost of patients undergoing ERCP followed by laparoscopic cholecystectomy showed LTCBDE to be significantly less (p< 0.05). Conclusion: Upfront laparoscopic CBDE is now a well-established practice at this unit. This study reports a high rate of bile duct stone clearance with LTCBDE, with minimal complications and obvious cost benefits. OB03-07  The Outcomes of Laparoscopic Common Bile Duct Exploration and Cholecystectomy: Results from a Prospective Multi-centre Cohort Study (The Choles Study) Andrei Tanase, United Kingdom S. Aroori, A. Tanase, Chole S Peninsula HPB Unit, Plymouth, University Hospitals Plymouth NHS Trust, United Kingdom Background: The aim of this study is to analyse the results of laparoscopic common bile duct exploration (LCBDE) and cholecystectomy (LC) performed across the UK and Ireland during Chole S trial period. Methods: We analysed the data on LCBDEs that were performed during the two-month CholeS Study trial period. Results: During the trial period, 256 patients (2.9%, 173 females, Median age: 59 years) out of 8820 LC underwent LCBDEs. During the same time period, 932 (10.6%) patients underwent endoscopic retrograde cholangio-pancreatography (ERCP) +and sphincterotomy (ES). Eighty percent of patients were either overweight or obese. 73 (28.5%) patients had ERCP and 112 (43.8%) patients had Magnetic resonance cholangio-pancreatography (MRCP), prior to LCBDE. The overall conversion rate was 13%. Two-thirds of patients had intra-operative cholangiogram prior to LCBDE. Median length of operation was 111 min (range: 75-155). Median length of hospital stay was 6 days (range: 4-11) for LCBDEs performed acutely (90/256, 35%) compared to 1 day (range: 1-4) for elective cases. The post-operative complication rate was 22.7%, and the bile leak rate was 5.3%. The all cause 30-day re-admission rate was 11.9% and 30-day mortality was 0.4%. Conclusions: LCBDE is still not commonly used treatment option for CBDS across the UK and Ireland. Nearly half of patients had pre-op MRCP and one fourth of patients had ERCP prior to surgery. Patients that had LCBDE in an acute situation had longer hospital stay compared to elective patients. Further studies are required to find out the reasons for low utilisation of LCBDE.