Extreme anticlockwise endoscopist repositioning for biliary cannulation in left-wall periampullary diverticulum

Background and study aims: A papilla located on the left wall of a periampullary diverticulum creates a mechanically unfavourable axis for biliary cannulation that is not readily corrected from the conventional endoscopist position. We describe the Extreme ABCD (Anticlockwise Bileduct Cannulation Diverticulum) technique, where ‘Extreme’ qualifies the degree of anticlockwise rotation applied - an endoscopist-repositioning manoeuvre designed to address this constraint without additional instrumentation. Patients and methods: Following observation in two index cases, the technique was adopted preemptively in consecutive patients with a confirmed left-wall periampullary papilla. Twentyfour patients were prospectively enrolled between July 2021 and February 2026. The endoscopist repositioned to the patient’s head end and applied extreme anticlockwise duodenoscope rotation to realign the instrument axis. The primary outcome was successful biliary cannulation. Adverse events were graded using the Cotton consensus criteria. Results: Successful biliary cannulation was achieved in 23/24 patients (95.8%), all within 5 minutes of adopting the repositioned stance. Primary guidewire cannulation was achieved in 20/24 (83.3%); the remaining 3 required needle-knife fistulotomy, performed from the same repositioned stance. Trainees were involved in 22 cases and cannulated independently in 16 (72.7%). Three of 24 patients (12.5%) experienced post-sphincterotomy bleeding graded as AGREE Grade I. No post-ERCP pancreatitis or major complications were observed. Conclusions: The Extreme ABCD technique is a simple, equipment-independent repositioning strategy for ERCP in left-wall periampullary diverticular anatomy. In this prospective series, it was associated with a high rate of biliary cannulation without rescue accessories and was feasible in a supervised training environment. Multicentre evaluation is warranted.