LAUSR

INTRODUCTION Caecal intubation may be unsuccessful by conventional colonoscopy in some patients. Single balloon-assisted colonoscopy (SBC) and cap-assisted colonoscopy (CAC) were studied to solve this problem. There was no head-to-head comparison between them. METHODS We conducted a randomised study from 2018 to 2021 to compare caecal intubation rate of SBC and CAC in patients with previous incomplete conventional colonoscopy. We recruited patients with incomplete conventional colonoscopy in two hospitals in Hong Kong. Patients were randomised into SBC group and CAC group in 1:1 ratio. In case of failure in caecal intubation by allocated method, alternative modality would be performed as rescue. RESULTS 44 patients were recruited. Caecal intubation rate was superior in SBC group (22/22,100%) than CAC group (16/22,72.7%) (p=0.02). No difference in caecal intubation time, polyp detection rate and diagnostic gain in area not examined previously. SBC induced less discomfort (modified Gloucester comfort score 2.14vs2.63, p=0.03) with use of comparable amount of midazolam and fentanyl as CAC. For patients failed caecal intubation by CAC, all (n=6) were rescued successfully by SBC. Body weight, body mass index (BMI) and waist circumference were greater in rescue subgroup. More patients were obese (BMI≥25 kg/m) in rescue subgroup (67vs19%). None in rescue subgroup had history of successful caecal intubation by conventional colonoscopy (0%vs56%, p=0.046). However, we failed to demonstrate significant association in multivariate analysis owing to small sample size. No adverse event was noted. CONCLUSION Single balloon-assisted colonoscopy is superior to cap-assisted colonoscopy in caecal intubation in patients with previous incomplete conventional colonoscopy.