Aims
Difficult extraction of common bile duct (CBD) stones remains a major determinant of ERCP safety, duration, and resource use. Although several factors have been proposed, robust real-life predictors applicable across centers are limited. This study aimed to identify simple, universally accessible radiologic and endoscopic parameters associated with difficult CBD stone extraction and to derive a practical predictive score.
Methods
All ERCPs performed for confirmed choledocholithiasis between 2016 and 2024 were retrospectively reviewed. Difficult extraction was defined as incomplete duct clearance during index ERCP, the need for mechanical lithotripsy, or requirement for repeat ERCP. Predictors included pre-procedural imaging findings (CBD diameter and stone burden on US/CT/MRI) and endoscopic parameters (stone size and number at cholangiography, papillary morphology including peri-/intradiverticular papilla, and early difficult-cannulation indicators such as pancreatic duct injection).
Results
Among 773 patients, 224 (29.0%) experienced difficult extraction. Stone size ≥15 mm was the strongest predictor (OR 4.6), followed by stone burden ≥3 stones (OR 1.7) and CBD dilation ≥12 mm (OR 1.6). Papillary anatomic difficulty (distorted or diverticular papilla) and early pancreatic duct injection markedly increased risk (OR 3.0). The strength and consistency of these predictors aligned with international series. Based on the most robust variables, a simple D-ERCP Score (0–6 points) was developed:
• Stone ≥15 mm: +2
• ≥3 stones: +1
• CBD ≥12 mm: +1
• Difficult-cannulation indicator: +2
Risk of difficult extraction increased stepwise: 7% (0–1 points), 28% (2–3 points), and 64% (≥4 points).
Conclusions
Nearly one-third of CBD stone extractions were difficult. Four routinely obtainable parameters—stone size, stone burden, duct dilation, and early difficult-cannulation signs—consistently predicted technical complexity. The D-ERCP Score, derived from a large real-world cohort, provides a practical, universally applicable tool to anticipate difficult extractions, optimize procedural planning, and improve the safety and efficiency of ERCP in routine practice.