Evaluate the outcomes of NKF as an initial method for biliary access.

Introduction

A previous feasibility study has suggested that needle knife fistulotomy (NFK) as an initial method for biliary access in patients with stones is associated with high levels of success and low rate of complications. This study evaluated the outcomes of NKF as an initial method for biliary access, in a large number of patients with any type of biliary pathology (tumors and stones), on the basis of success rate, complications and factors associated with success and complications.

Financial resources

All participants included in this study will perform ERCP, laboratory tests and other complementary diagnostic tests after a duly justified medical prescription. Therefore there are no additional costs or consumption of hospital resources.

Ethical considerations

In this study, participants will be included after informed consent. Anonymity and confidentiality will be safeguarded by assigning an individual numeric code. It will also be explained the possibility of withdrawing from the study at any time, with the guarantee of the total elimination of data. All researchers involved in the study will adhere to the Rules of Ethical Conduct and Best Practices in order to comply with the precepts of the Declaration of Helsinki, the Convention on Human Rights and Biomedicine, the guidelines of the Council for International Organizations of Medical Sciences and the Guide to Good Clinical Practice.

Statistical analysis

Qualitative variables will be summarized using absolute and relative frequencies, and quantitative variables will be summarized using the mean and standard deviation or the median and interquartile range, depending on their distribution profiles. The normality of the quantitative variables will be assessed using the histogram distribution.

Relations between categorical variables will be assessed using a chi-square test and Fisher´s exact test. Differences between two or more groups of independent non-normally distributed quantitative variables will be evaluated using a Kruskal-Wallis test.

To explain the risk of pancreatitis, a binomial logistic regression model with multiple predictors will be performed.

The null hypothesis will be rejected when the test statistics p-values are less than <0.05. Statistical analysis, sample size calculation and graphics will be performed using Stata software (StataCorp. 2015. Stata Statistical Software: Release 14. College Station, StataCorp LP)

Expected results

The results of this study will contribute to a better understanding of what is the best algorithm to follow when performing an ERCP.

Inclusion Criteria:

• ERCP with indication for biliary access
• Naïve papilla

Exclusion Criteria:

• Patients unable to sign or understand the informed consent
• Patients with surgically altered anatomy
• Patients with tumors of the papilla
• Previous sphincterotomy
• Spontaneous papillary fistula
• Papilla not visualized

• ERCP with indication for biliary access
• Naïve papilla (excluding flat or diverticular papillae according to Viana's classification)