The learning curve for needle knife precut sphincterotomy revisited

Background: There is no consensus on what constitutes adequate training for needle knife precut sphincterotomy.

Objective: The purpose of this study was to determine the number of procedures required before effective and safe precut sphincterotomy can be achieved.

Methods: This retrospective study examined the cumulative experience of a single endoscopist from January 2006-December 2015. Precut sphincterotomy success and complication rates were analyzed as a function of number of procedures performed. Acceptable success and complication rates were defined as 85% and 10% respectively. A one-sided binomial test was used to test success and complication rates of every 25 precut sphincterotomies performed.

Results: The index endoscopic retrograde cholangiopancreatography was successful in 141/158 (89.2%) patients who underwent precut sphincterotomy. This increased to 148/158 (93.7%) when endoscopic retrograde cholangiopancreatography was repeated on another day. Six precut sphincterotomies were required to achieve an 85% success probability. This was maintained consistently above 85% after 13 precuts, and was significantly higher (91.2%; p = 0.029) than 85% at the 125th precut. Bleeding and pancreatitis developed in 2/158 (1.3%) and 5/158 (3.2%). Probability of either complications remained below 5% after 50 precuts. No perforation occurred.

Conclusion: At least 13 precut sphincterotomies were required to achieve a sustained success rate greater than 85%. The probability of bleeding or pancreatitis was less than 5% after 50 precut sphincterotomies.