Development of a Scoring System for Predicting the Difficulty of Bile Duct Cannulation and Selecting the Appropriate Cannulation Method.

BACKGROUND: Selective biliary cannulation in endoscopic retrograde cholangiopancreatography can be challenging due to factors like papillary morphology. Various patterns indicate cannulation difficulty, but the combinations causing difficulty and the optimal cannulation method for each scenario are unclear. AIMS: This study aimed to identify cannulation difficulty patterns and develop a predictive scoring system for selecting the appropriate cannulation method. METHODS: We retrospectively compared 776 patients with naïve papilla, dividing them into conventional contrast cannulation (N = 510) and salvage technique (N = 266) groups. The salvage group included patients using pancreatic duct guidewire placement and/or wire-guided cannulation due to difficulties with the contrast method. Papillary morphology (Haraldsson's classification), periampullary diverticulum (PAD), and scope operability were analyzed using multiple regression to identify risk factors for cannulation difficulties. Factors were scored based on hazard ratios to access combinations causing difficulties. RESULTS: The salvage group had more older patients and higher frequencies of type 2 (small), type 3 (protruding or pendulous), type 4 (creased or ridged) papillae, PAD, and poor scope operability. Significant risk factors in the multivariate analysis included type 2 [odds ratio (OR) 6.88], type 3 (OR 7.74), type 4 (OR 4.06) papillae, PAD (OR 2.26), and poor scope operability (OR 4.03). Pattern recognition scores were significantly higher in the salvage group (1.31 vs. 3.43, P < 0.0001). CONCLUSIONS: Type 2-4 papillae, PAD, and poor scope operability are significant risk factors for cannulation difficulty. Pattern recognition scores based on these factors can predict cannulation difficulty and aid in selecting between conventional and salvage methods.

Reverse cannulation method as a strategy for aortic aneurysm surgery: A computational fluid dynamics study on minimizing neurological risks.

OBJECTIVES: To evaluate the blood flow velocity and wall shear stress in total arch replacement with a "shaggy" aorta, using computational fluid dynamics, and determine the optimal cannulation method. METHODS: A patient-specific aortic arch aneurysm model was constructed by using computed tomography scans. Three cannulas were assessed, as follows: dispersive with a steep angle, dispersive with a gentle angle, and the endo-hole type. The cannula tips were oriented toward the aortic arch (standard direction) and aortic root (reversed direction), with an ideal angle (base orientation: 0°), tip orientations rotated 20° clockwise and counterclockwise from the base orientation. The variables of interest included the blood flow velocity, streamlines, wall shear stress, and flow distribution. RESULTS: The standard direction resulted in variable accelerated flow and wall shear stress locations based on cannula tip orientation, leading to unstable cerebral branch flow. Minor deviation in the cannula tip angle and cannula type led to significant alterations in flow distribution. Conversely, in the reverse direction for all cannulas, no accelerated blood flow was observed in the proximal aortic arch or cerebral vessel ostia even with angular adjustments, helping maintain a stable cerebral branch flow. Minimal variation in blood flow distribution was observed across all cannula types and angles. CONCLUSIONS: Our simulations indicate that, irrespective of the cannula type or orientation, directing the cannula tip toward the aortic root (reversed direction) prevents accelerated blood flow in critical areas, suggesting its potential as an optimal approach for aortic arch surgery in "shaggy" aorta cases.