Needle Knife Sphincterotomy Does Not Increase the Risk of Pancreatitis in Patients With Difficult Biliary Cannulation

BACKGROUND & AIMS: Biliary cannulation is unsuccessful during 5%-10% of endoscopic retrograde cholangiopancreatography (ERCP) procedures. Needle knife sphincterotomy (NKS) can improve success of cannulation but is often used as a last resort and is associated with post-ERCP pancreatitis (PEP). We evaluated the safety and efficacy of performing NKS during early stages of difficult cannulation and the relationship between difficult cannulation and the risk of PEP. METHODS: We performed a prospective trial of consecutive patients with an intact papilla who were undergoing ERCP at tertiary referral center; 73 patients were defined as having difficult biliary cannulation according to predefined cannulation parameters. These patients were randomly assigned to groups that received either NKS or continued standard cannulation. Main outcome measures were PEP and successful biliary cannulation. RESULTS: Of 464 patients with an intact papilla undergoing ERCP, 73 met the criteria for difficult cannulation. Cannulation success in difficult cannulation cases was 86%, with a PEP rate of 19%. There was no difference in eventual cannulation success between the groups. However, 65% of the patients assigned to the standard cannulation group required crossover to NKS. There was no significant difference in development of PEP among patients in the early NKS group (20.5%) vs standard cannulation (17.6%). Pancreatic duct stents were inserted in 23 of the patients in the early NKS arm and in 15 in the standard cannulation arm. The number of cannulation attempts (more than 7) increased the risk of PEP (P < .01). On the basis of multivariate analysis, independent risk factors for PEP were failure of early cannulation and failure of biliary cannulation. CONCLUSIONS: Early application of NKS during difficult cannulation does not increase the risk of PEP. The risk of PEP increases greatly after 7-8 attempts at or failure of cannulation. Further studies are required to assess whether early implementation of NKS during difficult cannulation reduces the development of PEP. Australia and New Zealand Clinical Trials registry: ANZTRN 12,612,000,060,842.